Milling Technical Guide: Applications, Products & Recommendations

MILLING Introduction D2 APPLICATIONS Getting started D3 Milling different materials D 32 Shoulder milling Face milling Profile and turn milling Slot and thread milling Dedicated methods Trouble shooting D 42 D 54 D 66 D 84 D 100 D 128 PRODUCTS 90° shoulder milling cutters D 134 CoroMill® 490, CoroMill® 390, CoroMill® 290, CoroMill® 690, Coromant Finishing Long Edge Cutter, CoroMill® 790, CoroMill® Century 10° – 75° face and plunge milling cutters D 146 CoroMill® 345, CoroMill® 245, CoroMill® 365, AUTO, CoroMill® 360, T-Max 45, CoroMill® 210, Cormant Plunge cutter Round insert cutters D 161 CoroMill® 200, CoroMill®300 Ball nose cutters D 164 CoroMill® 216, CoroMill® 216F Finishing Slot, groove, side/face and thread milling cutters CoroMill® 327, CoroMill® 328, CoroMill® 329, T-Max Q-Cutter, CoroMill® 331 D 166 Solid carbide and exchangeable head cutters CoroMill® Plura, CoroMill® 316 D 178 Extended offer D 186 Grade information D 188 Feed recommendations D 192 D1 MTG09 Milling D1-D21.indd 2 2009-08-12 08:12:01 MTG09 Milling D1-D21.indd 1 2009-11-24 13:06:51 Milling – introduction General turning A Parting and grooving B Threading C Milling D Drilling E Boring F Tool holding/ Machines G When the first CoroMill cutters were introduced in the early 90s, a new standard was set on the market when it comes to productivity, accuracy and realiability. Since then, the CoroMill family has grown and developed in a remarkable way. Today’s comprehensive range of milling solutions meets every need and machining trend. Unique and innovative technologies have always been the basis for all CoroMill concepts and the latest developments are no exception, for example, the smart insert and tip seat designs which are the prerequisites for the unmatched performance of cutters, such as the CoroMill 345, CoroMill 490, CoroMill 690, etc. The new exchangable head (EH) coupling system, which enables the versatility of the CoroMill 316 end mill range, is another example of an innovation, developed by Sandvik Coromant. Trends Machines and machining methods • Increased flexibility with 5-axes machining centres and multi-task machines • Smaller, less stable machines - light and fast milling techniques – lower depths of cut • Fewer machines/set-ups to complete a component • Longer tool lengths Components and material • Stronger, lighter and more corrosion-resistant materials • Thin-walled components • Near net shape castings and forgings Together with a wide assortment of insert geometries and grades, a suitable CoroMill solution is always available, irrespective of workpiece material and machining conditions. Materials H Introduction Information/ Index I D2 MTG09 Milling D1-D21.indd 2 2009-11-24 13:06:53 Milling – getting started General turning Getting started A Milling methods Milling is the most flexible machining method available and can machine almost any shape. The downside of this flexibility is that many variables are built into the process, making it more challengng to optimize. This chapter identifies these variables and helps you choose the best method and tools, depending on the application. Parting and grooving B Getting started provides an overview of the milling products, machine types, definitions of variables and general recommendations, see pages D 3 – D 31. Milling recommendations from a workpiece material perspective are given in Milling in different materials, see pages D 32 – D 41. It answers questions like: Should cutting fluid be used when milling titanium? What cutter type is best suited for aluminium? Can ceramic inserts be used in cast iron? etc. C Threading Milling used to be divided into face, shoulder, slot and profile milling, but with the development of machines and softwares, the number of methods has grown and turn-milling, thread milling, circular ramping, trochoidal milling, etc. are very common in today's operations. In this chapter, milling has been divided into the following areas: D Milling • Face milling, see page D 54. • Shoulder milling, see page D 42. • Profile and turn milling, see page D 66. • Slot and thread milling, see page D 84. • Dedicated methods, see page D 100. The last section explains methods like ramping, plunging, trochoidal, etc. Drilling E Boring F Tool holding/ Machines G Choice of method Three different areas should be considered to determine the best method and tooling solution. Materials H P M K N S H 2. Component material, shape and quantity 3. Machine parameters I D3 MTG09 Milling D1-D21.indd 3 Information/ Index 1. Milling component feature 2009-11-24 13:07:07 General turning A Parting and grooving B Initial considerations 1. The milled configuration Milling has been evolved into a method that machines a very broad range of operations. In addition to all the conventional applications, milling is a strong alternative for producing holes, threads, cavities and surfaces that used to be turned, drilled or tapped. The configurations to be milled have to to be carefully considered. These can be located deep, requiring extended tooling, or contain interruptions and inclusions. Threading C Milling – getting started D 2. The component Milling Workpiece surfaces can be demanding, with cast skin or forging scale. In cases of bad rigidity, caused by thin sections or weak clamping, dedicated tooling and strategies have to be used. E Drilling The workpiece material and its machinability must also be analyzed to establish optimal cutting data. 3. The machine G The machine is of great importance for the choice of milling method. Face/shoulder or slot milling can be performed in 3-axes machines, while milling 3D profiles require alternatively 4- or 5-axes machines. Tool holding/ Machines Boring F P M K N S H Turning centres today often have milling capability due to driven tools, and machining centres often have turning capability. CAM developments mean that 5-axis machines are increasingly common. They offer increased flexibility, but stability can be a limitation. For more information about machines for milling, see page D 10. Materials H Information/ Index I D4 MTG09 Milling D1-D21.indd 4 2009-11-24 13:07:12 A General turning Milling – getting started Choice of method – example Face milling 45° entering angle 90° entering angle Parting and grooving B 10° entering angle C Advantages + High productivity + Optimized for face milling Disadvantages – Moderate depth of cut CoroMill® 490 Advantages + Versatile cutter that can be used for many other operations + Low axial forces – favourable for thin walled components + Relatively large depth of cut in relation to the insert size Advantages + High productivity + Extremely high feed + Axial cutting force direction – favourable for spindle stability Disadvantages – Low depth of cut D Milling Disadvantages – Lower productivity CoroMill® 210 Threading CoroMill® 345 High productivity The basic choice Versatile Mixed production High productivity Problem solver E Drilling Opening up a cavity/pocket F Drilling + plunge milling Circular ramping Boring Drilling + circular milling The basic choice for pockets Disadvantages – Low material removal Problem solver Long overhangs Advantages + Reduced tools – no drill needed + Flexible – produces wide range of sizes + No cutting fluid required – good for open machines + Suitable for all machine concepts and configurations H Disadvantages – Less productive for large cavities Materials Disadvantages – Requires a stable machine – Chip evacuation – horizontal machine – Careful programming required Advantages + Problem solver in long overhang applications + Simple programming suitable for older/ multi-spindle machines The basic choice for 3D cavities I D5 MTG09 Milling D1-D21.indd 5 Information/ Index Advantages + High material removal for non-round holes + First choice in aerospace frame titanium structural parts Tool holding/ Machines G 2009-11-24 13:07:13 General turning A Milling – getting started Application overview – milling Shoulder milling see page D 42 Parting and grooving B C Face milling Threading see page D 54 High feed D Wiper Profile and turn milling Milling see page D 66 E Turn milling Drilling Roughing to finishing of concave and convex surfaces F Slot and thread milling Boring see page D 84 Radial slot milling G Axial slot milling Thread milling Tool holding/ Machines Dedicated methods see page D 100 Circular milling Plunge milling H Chamfer milling Materials Closed angles Slicing Linear and circular ramping Information/ Index I D6 MTG09 Milling D1-D21.indd 6 2009-11-24 13:07:32 Product overview – milling 90° shoulder milling cutters CoroMill® Plura CoroMill® 316 CoroMill® 390 A General turning Milling – getting started CoroMill® 490 D 179 D 183 D 136 D 134 CoroMill® 690 CoroMill® 790 CoroMill® Century CoroMill® 290 S N N D 140 D 143 Cutters with a 90˚ entering angle are very versatile and the most common type of cutter. Shoulder face mills, end mills and long edge cutters are all included in this group. • CoroMill 490 is the first choice cutter for general shoulder face milling. • The CoroMill 390 is a concept of end mills, shoulder face mills and long edge cutters with good ramping capabilities. Vibration dampened tools and a wide range of radius inserts are available for dedicated operations. D 144 Threading Page C D 139 • The solid carbide cutters, CoroMill Plura and CoroMill 316, with exchangeable heads, cover the smaller diameter range. D • CoroMill 690 is a long edge cutter dedicated for titanium milling. • CoroMill 790 is the cutter, mainly used for aluminium, with the best ramping capability. • Other cutters in this group are the Coromant finishing long edge cutter and the Sandvik Auto-FS finishing face mill. Milling Page Parting and grooving B Drilling E 10° - 75° face and plunge milling cutters CoroMill® 245 D 179 D 183 D 158 D 148 CoroMill® 345 CoroMill® 360 CoroMill® 365 Page D 146 This wide range of cutters are used mainly for face milling operations, but cutters with very small entering angles that are suitable for plunge milling also belong to this group. • CoroMill 345 is the basic concept for for general face milling and CoroMill 245 the complementary choice. • CoroMill 365 is mainly used for cast iron. D 155 Auto D 152 T-Max 45 D 156 G D 150 • CoroMill 360 is the real heavy duty milling cutter. • CoroMill 210 and the corresponding versions of CoroMill 316 and CoroMill Plura are well adapted for use with high feed face milling techniques. These cutters are excellent for ramping operations and CoroMill 210 can also be used for plunge milling. • Other cutters in this group are the Sandvik Auto for cast iron milling and the T-Max 45 for heavy machining. ➤ D7 MTG09 Milling D1-D21.indd 7 H Materials Page F Boring CoroMill® 210 Tool holding/ Machines CoroMill® 316 High feed I Information/ Index CoroMill® Plura High feed 2009-11-24 13:07:36 General turning A Milling – getting started ➤ Round insert and large radius cutters Parting and grooving B C Page CoroMill® Plura Large radius CoroMill® 316 Large radius CoroMill® 200 CoroMill® 300 D 178 D 182 D 164 D 162 Round insert cutters are very versatile, and are used for both demanding face milling as well as profiling operations, and have excellent ramping capabilities. Threading • The light cutting CoroMill 300 is the first choice. Also available in toroid end mill design as an alternative to ball nose cutters. • CoroMill 200 is the tough choice for more demanding applications. • CoroMill Plura and CoroMill 316 with large radius can be regarded as round insert cutters. D Ball nose cutters CoroMill® 316 D 178 D 182 CoroMill® Ball nose Milling CoroMill® Plura E Page D 164 D 165 Drilling Ball nose cutters are primarily used for profile milling of 3D shapes (sculptured surfaces). • Ball nose designs of the CoroMill Plura and CoroMill 316 are suitable for roughing or finishing operations. • The indexible insert cutter CoroMill 216 is a roughing and semi-roughing cutter, while CoroMill 216F is dedicated for finishing operations. Boring F Slot, groove, side/face and thread milling cutters Tool holding/ Machines G Materials H Page CoroMill® Plura CoroMill® 327 CoroMill® 328 CoroMill® 329 CoroMill® 331 D 95 D 166 D 168 D 170 These cutters were primarily developed for milling deep or shallow grooves. When the groove is produced in a helical path, they can form a thread. • CoroMill 327 and 328 have optimized insert designs for threading and circlip grooving, respectively. • The CoroMill 329 is for general milling of grooves and shallow slots. The Q-cutter is a complementary tool for slots that exceed the reach of the CoroMill 329. • CoroMill 331 is a comprehensive concept for all types of side and face milling operations, including back-facing. Information/ Index I D8 MTG09 Milling D1-D21.indd 8 2009-11-24 13:07:38 A General turning Milling – getting started Tool maintenance Check the insert seats regularly to ensure that they have not been damaged during machining or handling. Make sure that the insert seats are free from dirt or metal chips from machining. B Parting and grooving Replace worn or damaged screws and washers. Use a torque wrench to ensure correct screw-tightening. To get the best performance, we recommend cleaning all male and female parts and lubricating them with oil at least once a year. Lubricant should be applied, when needed, to the screw thread as well as the screw head face. C To get the best performance out of the milling tools, a torque wrench should be used to obtain the correct tightening of the assembled boring tool and insert. Torque that is set too high will affect the performance of the tool negatively and cause insert, washer and screw breakage. D Milling Torque that is set too low will cause slide or insert movement, vibrations and degrade the cutting result. See Main catalogue to find the correct tightening torque. Threading Torque wrench E F Boring • Chips are very hot with sharp edges and should not be moved with bare hands. Chips can cause burns to the skin or damage to the eyes. • Be sure that the insert and component are tight and secured in their holders to prevent them from coming loose during use. Too much overhang can result in vibration and tool breakage. • Use appropriate safety guards or machine encapsulations to securely collect particles such as chips or cutting elements, which may spin off. • Make sure that the machine has the required torque and power needed for rough milling operations, large depths of cut or large diameters. Drilling Safety precautions – danger points Warning! Max spindle revolution At high RPM's, the weight of the insert and clamping elements increase, which can effect the clamping arrangement. It is recommended that all high speed manufacturing takes place only in a well-protected machine set-up. Correct insert clamping is achieved by tightening the 16 mm screw, using a torque of 2 Nm, and the 22 mm insert with 5 Nm. Note: A 19 gram insert weighs 350 kg at 37,500 rpm. Tool holding/ Machines G H Materials Before mounting the insert, make sure that the insert and its seat are in perfect condition and free from burrs or any particles, which may seriously affect the clamping arrangement. D9 MTG09 Milling D1-D21.indd 9 Information/ Index I 2009-11-24 13:07:38 General turning A Parting and grooving B Machines for milling Machine tool configuration – number of axes Previously, machines could be split into four categories – horizontal or vertical, and turning or milling. Today, machines are developing in all directions. Turning centres now have milling capability due to driven tools, and machining centres have turning capability – turn mill or mill turn machines. CAM developments mean that five-axis machines are increasingly common. The results of these trends create new demands and opportunities for tooling: • Increased flexibility • Fewer machines/set-ups to complete a component • Reduced stability • Longer tool lengths • Lower depth of cuts. Vertical machining centre with a fifth A-axis. Threading C Milling – getting started D Vertical machining centre with a fifth B-axis. Milling Spindle orientation – horizontal or vertical? Drilling E Boring F Horizontal: • Favourable for milling larger components. • Facilitates chip evacuation in cavity milling, and prevents re-cutting. • Less mass to accelerate/decelerate. • Often, four axes provide access to three sides. • Ergonomic and economic pallet technology. • Most common machine type for use of side and face milling cutters. Small vertical machining centers: • Small total envelope, requires little space in the workshop. • Well suited to high speed/feed – light and fast. Horizontal machining centre with 5 axes. Large vertical machining centers: • Provide better stability while the workpiece is resting on the table. • Suitable for larger and heavier workpieces. • Column types for huge components. • Can work with longer and heavier tool set-ups. Tool holding/ Machines G Materials H Multi-task machine with 5 axes. Stability The condition and stability of the machine have an effect on the quality of the surface, and can also impair tool life. Excessive wear on the spindle bearings or feed mechanism can result in a poor surface structure. The stability of the entire tool set-up is of outmost importance. Factors such as tool overhang, Coromant Capto coupling, tuned adaptors, etc. should be considered. Namnlöst-1 1 Information/ Index I 2009-08-31 09:29:34 Vertical and horizontal 3-axis machines. D 10 MTG09 Milling D1-D21.indd 10 2009-11-24 13:07:45 Power and torque Torque Basically, the power requirements in milling vary along with the: A General turning Milling – getting started • amount of metal to be removed • average chip thickness • cutter geometry • cutting speed. The greater the metal removal rate (Q cm³/min), the higher the power requirement. Low spindle speeds for roughing of exotic materials place great importance on the availability of sufficient power and torque. Power Spindle speed A machine with insufficient torque and power will produce fluctuating chip thickness, which in turn causes unstable performance. Parting and grooving B C The majority of modern machining centres have direct driven spindles. Ever increasing spindle speed capacity and/or capability results in: Threading • Lower torque at higher rpm • Lower power at lower rpm Therefore, machines with high rpm capabilities have limitations for roughing wíth larger diameter cutters, which require low rpm and high power. Machining strategies need to be adapted. This explains the trend in light and fast machining – which uses a smaller cutter diameter, small depth of cut, ap/ae, and high feed per tooth, fz. D Milling Machines for components requiring high power at low rpm can be geared to produce an optimum performance for both roughing and finishing. E Drilling Spindle sizes ISO 30, 40, 50 and 60 spindles have natural built-in advantages and limitations. F The size of the spindle will define the maximum milling cutter diameter and the depth of cut that the machine is capable of handling. Boring Heavy roughing requires a larger spindle, whereas high speed milling requires lower torque, making a smaller spindle more suitable. Although there are exceptions, due to varying machine tool conditions, a general rule for selecting the cutter size is: G Tool holding/ Machines ISO 60 – “larger cutters”. ISO 50/Coromat Capto size C8 – Dc 160 mm. ISO 40/Coromat Capto size C6 – Dc 100 mm. ISO 30/Coromat Capto size C4 – Dc 50 mm. Components requiring long edge cutters require, at a minimum, an ISO 50 or Coromant Capto size C8 spindle. H Tool coupling integrated in the spindle provides the best stability. Materials On gantry machines and other larger machine tools, cutters may be direct mounted on the spindle nose, which provides extreme stability and the smallest possible protrusion. Large gantry heavy duty milling machine. D 11 MTG09 Milling D1-D21.indd 11 Information/ Index I 2009-11-24 13:07:47 General turning A Parting and grooving B Threading C Milling D E Milling – getting started Milling definitions The milling cutter Entering angle – kr (degrees) The major cutting edge angle (kr) of the cutter is the dominant factor affecting the cutting force direction and the chip thickness, see page D 18. Cutter diameter – Dc (mm) The cutter diameter (Dc) is measured over the point PK, where the main cutting edge meets the parallel land. Dc is the diameter that in most cases appears in the ordering code, with the exception of the CoroMill 300, for which D3 is used. The most important diameter to consider is (Dcap) – the effective cutting diameter at the actual depth of cut (ap) – used for calculation of the true cutting speed, see page D 76. D3 is the largest diameter of the insert, for some cutters it is equal to Dc. Cutting depth – ap (mm) The cutting depth (ap) is the difference between the uncut and the cut surface in axial direction. Maximum ap is primarily limited by the insert size and machine power. Drilling Another critical factor in roughing operations is torque, and in finishing operations, it is vibration. F Boring Cutting width – ae (mm) The radial width of the cutter (ae) engaged in cut. Especially critical in plunging step over, and for vibration in corner milling, where maximum ae is especially critical. G Tool holding/ Machines Radial immersion – ae / Dc Radial immersion (ae / Dc) is the width of the cut in relation to the diameter of the cutter. H Number of effective cutting edges on the tool – zc Materials For determining the table feed (vf) and the productivity. This often has a critical influence on chip evacuation and operational stability. The total number of cutting edges on the tool – zn I Information/ Index zc < zn zc = zn / 2 D 12 MTG09 Milling D1-D21.indd 12 2009-12-06 08:38:36 A General turning Milling – getting started Pitch – u (mm) Distance between the effective cutting edges (u). For a specific Sandvik Coromant cutter diameter, you can choose between different pitches: coarse (-L), close (-M), extra close (- H). An X added to the code, denotes a cutter version whose pitch is slightly closer than its basic design. Parting and grooving B Differential pitch Indicates an unequal space between the teeth on a cutter. This is a very effective way to minimize vibration tendencies. For more information about pitch, see page D 17. C Threading The milling insert Insert geometry γ M γ β Parameter H β β L D γ Geometry M Milling L H E Edge strength Cutting forces Power consumption Low Medium High Max. chip thickness Drilling Heat generated A closer study of the cutting edge geometry reveals two important angles on the insert: • rake angle (γ) • cutting edge angle (β) F Boring The macro geometry is developed for work under light, medium or heavy conditions. • L (Light) geometry has a more positive, but weaker edge (large γ, small β) • H (Heavy) geometry has a stronger, but less positive edge (small γ, large β) The macro geometry affects many parameters in the cutting process. An insert with a strong cutting edge can work at higher loads, but also generates higher cutting forces, consumes more power and generates more heat. G Tool holding/ Machines Material optimized geometries are designated with the ISO classification letter. For example, geometries for cast iron: KL, KM, KH. The most important part of the cutting edge for producing the surface is the parallel land bs1 or, when applicable, a convex wiper land bs2, or corner radius rε. Corner radius (r) r Parallel land (bs1) Radius (Rbo) Wiper land (bs2) bs1 I D 13 MTG09 Milling D1-D21.indd 13 Information/ Index Insert corner design Materials H 2009-12-06 08:38:56 General turning A Parting and grooving B The milling process Cutting speed – vc (m/min) This indicates the surface speed at diameter and forms a basic value for calculating cutting data. Recommended cutting speeds for all materials and for different hex values are available in the Main catalogue. Effective or true cutting speed Indicates the surface speed at the effective diameter (Dcap). This value is necessary for determining the true cutting data at the actual depth of cut (ap). This is a particularly important value when using round insert cutters, ball nose end mills and all cutters with larger corner radii, as well as cutters with an entering angle smaller than 90 degrees. vc = Dcap × π × n 1000 Threading C Milling – getting started Milling D Drilling E The number of revolutions the milling tool makes per minute on the spindle. This is a machine oriented value, which is calculated from the recommended cutting speed value for an operation. Feed per tooth – fz (mm/tooth) A basic value for calculating cutting data, such as table feed. It is also calculated with consideration of maximum chip thickness (hex) and entering angle. Recommended (fz) starting values for most CoroMill cutters are available on page D 192 and in the Main catalogue. For the CoroMill Plura, the type of machined material is also taken into account. Boring F Spindle speed – n (rpm) fz = G vf n × zc Tool holding/ Machines Feed per revolution – fn (mm/rev) Auxiliary value indicating how far the tool moves during one complete rotation. It is used specifically for feed calculations and often to determine the finishing capability of a cutter. H Materials Feed per minute – vƒ (mm/min) The table feed, machine feed or feed speed in mm/min It represents the movement of the tool in relation to the workpiece, dependent on feed per tooth (fz) and number of teeth in the cutter (zn). I Information/ Index Namnlöst-1 1 D 14 MTG09 Milling D1-D21.indd 14 2009-12-06 08:48:10 A General turning Milling – getting started Maximum chip thickness – hex (mm) This value is a result of the cutter engagement as it is related to (fz), (ae) and (kr). The chip thickness is an important consideration when deciding the feed per tooth, to ensure that the most productive table feed is employed. See page D 20. Parting and grooving B Average chip thickness – hm (mm) A useful value in determining the specific cutting force, used for net power calculations. C Threading Metal removal rate – Q (cm³/min) The volume of metal removed in cubic mm per minute. It is established using the values for cutting depth, width and feed. D Specific cutting force – kct (N/mm²) Milling A factor used for power calculations. The specific cutting force relates to the material resistance when cut at a specific chip thickness value. For more information, see Materials, Chapter H. E Machine tool oriented values, which assist in calculating the net power to ensure that the machine can handle the cutter and operation. Pc = ap × ae × vf × kc ηmt × 60 × 106 For more formulas and calculations, see Information/ index, Chapter I. Machining time – Tc (min) F The definitions used are the most common on the market. When multiple expressions exists to describe the same function, the Sandvik Coromant nomenclature is used. G High Speed Machining The designation HSM is not used in this guide. HSM refers to topics dealt with separately in different sections. Linear ramping A simultaneous straight movement in axial and radial feed directions. Circular milling A circular tool path on a constant z-level (circular interpolation). Waterline milling Milling on a constant z-level. Point milling A shallow radial cut with round insert or ball nose cutters in which the cutting zone is moved away from the tool centre. Scallop A configuration with cusps that occurs when producing sculptured surfaces. Tool holding/ Machines Expressions used in the guide Boring Machining length (lm) divided by the table feed (vf). Drilling Power Pc and efficiency ηmt H Materials Circular ramping A circular ramping tool path (helical interpolation). D 15 MTG09 Milling D1-D21.indd 15 Information/ Index I 2009-11-24 13:07:50 Milling – getting started Definition - Productivity in milling B The seven examples below show how cutting data can be increased above normal recommendations and contribute to a higher productivity: Productivity in milling, when defined as metal removal rate, Q cm³/min, can be optimized in many different ways. Choosing the right tool for the application is important, but the choice of cutting parameters is equally critical. 1 Face milling C Application Threading Parting and grooving General turning A vc n fz z vf ap ae Cutting parameters D 2 Peripheral milling 3 4 5 6 7 Profile milling Face milling Face milling Face milling Face milling Small ent.angle Heavy duty Wiper Cast iron High High High High Small High High Small Aluminium Small ae/Dc Finishing High High High High High High High High Small Small High Small High High High Milling Q = vf x ap x ae/1000 (cm³/min), where vf = fz x n x zn (mm/min) Drilling E Boring F 2. Peripheral milling – High cutting speed, vc, and feed, fz When the cutter has a small radial depth of cut, ae, the time in cut per rev. is short, consequently the cutting edge temperature will be low. This means that the cutting speed can be raised above normal recommendations. Also, the feed, fz, can be increased, because the maximum chip thickness, hex, will be low. The feed will be limited by the surface finish requirement. For more information, see page D 50 3. Profile milling – High spindle speed, n This milling technique is often called High Speed Machining (HSM) and is typical in finishing or super-finishing profiling operations with a ball nose end mill. For more information, see page D 76. 4. Face milling with small entering angle and high feed, fz Cutters with very small entering angles enabla a dramatic increase in the feed, fz, due to the chip thinning effect when ap is small. For more information, see page D 20. 5. Heavy duty milling – large depth of cut – heavy duty In heavy duty applications, large insert cutters with large diameters are used. Cutting speed is normal, but high ap and fz, combined with a large ae, make it very productive. For more information, see page D 62. 6. Finishing with wiper inserts In a finishing operation with a large face milling cutter, the feed, fz, normally has to be kept low. However, by using wiper inserts in the cutter, the feed can be raised 2–3 times without sacrificing the surface quality. For more information, see page D 64. 7. Face milling – extra close pitch cutter In milling short-chipping materials, like grey cast iron, a face milling cutter with an extra close pitch can be used, resulting in high table feed. Also, in HRSA material where cutting speed is normally low, an extra close pitch results in a high table feed. Tool holding/ Machines G 1. Face milling – High cutting speed, vc In machining aluminium, and sometimes in machining cast iron with CBN or ceramic inserts, cutting speeds of more than 1000 m/min can be used, which results in a very high table feed, vf. Also, this type of machining can be called High Speed Machining (HSM). Materials H Information/ Index I "Light and fast" technique: Methods 2, 3 and 4 are based upon small depth of cut, ae, and/or ap, which generate low cutting forces and heat, making it possible to increase speed and/or feed. D 16 MTG09 Milling D1-D21.indd 16 2009-11-24 13:07:52 Milling – getting started General turning General guidelines A When choosing the most suitable number of effective cutting edges, zc, for the operation, it is also essential to consider the pitch (distance between the cutting edges). All CoroMill cutters are available in evenly pitched versions. However, increasing the number of edges changes the design of the tool. Shorter distances between tool edges mean that there is less space left for chip evacuation and, in most cases, the cutter must be evenly pitched. Depending on size and the number of cutting edges, some cutters are also available in a differentially pitched version (unequal spacing of the teeth around the cutter). Power requirement is often a factor that limits the possible number of cutting edges that are engaged in cut. Sandvik Coromant offers three pitches for cutters to optimize the particular application: C Coarse –L Close –M Extra close –H The pitch mainly affects: • Productivity • Stability • Power consumption • Suitable workpiece material. The closer pitched cutters, -M and -H, are used when stability is good and for low ae applications. This ensures that more than one tooth is always engaged in cut. Threading Differentially pitched cutters are advantageous because they break up harmonic vibrations and therefore increase stability, especially useful with a high ae and a long overhang. B Parting and grooving Pitch and the number of cutting edges D Milling By increasing the number of cutting edges, the table feed can be increased, while retaining the same cutting speed and feed per tooth, without generating any more heat at the cutting edge. Drilling E Evenly or differentially pitched cutters, depending on concept, with medium number of edges. • First choice for roughing in stable conditions • Good productivity • Good chip space for roughing in ISO P, M and S materials. Extra close pitch –H Evenly pitched cutters with maximum number of inserts. • First choice for high productivity with low ae (more than one edge in contact) • Roughing and finishing in ISO K materials • Roughing in ISO S materials in combination with round inserts. F G Tool holding/ Machines Differentially pitched cutters with reduced number of edges. • First choice for unstable operations due to lowest cutting forces • Limited power • Extended tooling • Full slotting operations • Long-chipping materials ISO N (large chip pocket). Close pitch –M Boring Coarse pitch –L Materials H Note: An X added to the code, describes a cutter version that has a slightly closer pitch than its basic design. D 17 MTG09 Milling D1-D21.indd 17 Information/ Index I 2009-11-24 13:07:52 General turning Milling – getting started Entering angle B The most common entering angles are 90°, 45°, 10° and those eliminated by round inserts, such as cutters using ball nose inserts at smaller depths of cut. Parting and grooving A • Decreasing the entering angle, kr, on straight edges reduces chip thickness, hex, for a given feed rate, fz. This chip thinning effect spreads the amount of material over a larger part of the cutting edge. • Smaller entering angles provide a more gradual entry into the cut, reducing radial pressure and protecting the cutting edge. • Higher axial forces at decreasing entering angles will increase the pressure on the workpiece. This is the angle between the main, leading cutting edge of the insert and the workpiece surface. Chip thickness, cutting forces and tool life are all especially affected by the entering angle. Threading C 90° cutters • Main application area is square shoulder milling. • Generates mostly radial forces, in direction of the feed. • The surface being machined will not be exposed to high axial pressure, which is advantageous for milling workpieces with a weak structure or thin walls, and in cases of unstable fixture. D Milling Cutter assortment: CoroMill 290, CoroMill 390, CoroMill 490, CoroMill 590, CoroMill 690, CoroMill 790, CoroMill Plura and Auto-FS – and for special purposes, the side and face milling and grooving cutters: CoroMill 331, CoroMill 327/328 and the T-Max Q-cutter. Drilling E Boring F Tool holding/ Machines G • General choice for face milling. • Generates well balanced radial and axial cutting forces. • Smooth entry into cut. • Low tendency for vibrations when milling with long overhangs or smaller/weaker tool holders and couplings. • Especially suitable for milling workpieces in short-chipping materials that easily fritter if excessive radial forces act on the gradually reduced amount of material left at the end of a cut. • Formation of a thinner chip allows for high productivity in many applications, because of the opportunity for higher table feed while maintaining a moderate cutting edge load. Cutter assortment: CoroMill 245, CoroMill 345, T-Max 45 and Sandvik Auto programme. Materials H 45° cutters Information/ Index I D 18 MTG09 Milling D1-D21.indd 18 2009-11-24 13:07:53 A General turning Milling – getting started 60° to 75° cutters • Special purpose face mills offering larger depth of cut, compared to the general choice face mills. • Lower axial forces, compared to 45° face mills. • Better edge strength, compared to 90° cutters. B Parting and grooving Cutter assortment: CoroMill 360, CoroMill 365, Auto AF. Threading C • High-feed and plunge milling cutters. • The thin chip generated, allows for very high feeds per tooth, fz, at small depths of cut and, consequently, for extreme table feeds, vf. • The dominating axial cutting force is directed towards the spindle and stabilizes it. This is favorable for long and weak set-ups, as it limits vibration tendencies. • For plunge milling of cavities, or whenever use of an extended cutter is required. • Effective in hole making using three axes. Cutter assortment: CoroMill 210, CoroMill 316 and CoroMill Plura high feed cutters. D Milling 10° cutters Drilling E F Boring Round inserts or cutters with a large corner radius • Efficient roughing and general purpose cutters. • Corner radius provides very strong cutting edge. • High table feed rate capability due to thinner chips generated along the long cutting edge. • The chip-thining effect makes these cutters suitable for machining titanium and heat resistant alloys. • Depending on cutting depth variations, ap, the entering angle changes from zero up to 90°, altering the cutting force direction along the edge radius, and consequently the resulting pressure during the operation. Tool holding/ Machines G Cutter assortment: CoroMill 200, CoroMill 300 and – at smaller depths of cut – CoroMill 390 radius insert cutters; the ball nose cutters CoroMill 216 and CoroMill 216F. Also, the solid carbide end mills, CoroMill Plura and CoroMill 316, are available in ball nose versions with a large corner radius. Materials H D 19 MTG09 Milling D1-D21.indd 19 Information/ Index I 2009-11-24 13:07:53 General turning A Parting and grooving B Milling – getting started Maximum chip thickness Maximum chip thickness is the most important parameter for achieving a productive and reliable milling process. Effective cutting will only take place when this is maintained at a value correctly matched to the milling cutter in use. • A thin chip with a hex value that is too low, is the most common cause of poor performance resulting in low productivity. This can negatively affect tool life and chip formation. • A value that is too high will overload the cutting edge, which can lead to breakage. Threading C Feed per tooth can be increased in the three following situations due to the chip thinning effect when: 1. Using straight edge cutters with entering angles lower than 90°. 2. Using round inserts or large radius inserts, at smaller depths of cut, ap. 3. Peripheral milling at a small radial engagement, ae/De. Milling D Chip thinning allows for increased feed E 1. Straight edge insert Drilling For straight edge inserts, chip thickness, hex, is equal to fz when entering angle is 90 degrees. As entering angle, kr, decreases, fz can be increased. Example: If the maximum chip thickness, hex, is 0.1 and the entering angle, kr, is 45°, the feed recommendation, fz, is 1.4 x 0.1 = 0.14 mm/tooth. Boring F Entering angle Modification factor kr hex (mm) G Tool holding/ Machines fz (mm/tooth): 1.0 1.0 1.1 1.4 5.8 90° 75° 65° 45° 10° min. 0.1 0.10 0.10 0.11 0.14 0.58 start 0.15 0.15 0.16 0.17 0.21 0.86 max. 0.2 0.20 0.21 0.22 0.28 1.15 H k=90° kr 45° kr 10° Materials hex = fz x sin kr Information/ Index I D 20 MTG09 Milling D1-D21.indd 20 2009-12-06 09:07:21 2. Round and radius insert cutters • Best performance is achieved when the entering angle, kr, remains under 60°, when using round insert cutters or ball nose end mills at limited depths of cut. This means that the depth of cut should not exceed 25% x insert diameter, iC. <60° <25% iC • For larger depths of cut, it is better to use square inserts with a constant kr of 45°. A General turning Milling – getting started • The chip thickness, hex, varies with round inserts, and depends on the entering angle. With low ap/iC ratios, the feed can be increased considerably in order to raise the chip thickness to a desired level. coskr = Parting and grooving B (0.5 iC - ap) 0.5 iC • Round inserts have a higher maximum chip thickness capability than straight edge solutions, due to the stronger insert shape and longer cutting length. Threading C fz = hex × iC D 2 × √ ap × iC − ap² Example: CoroMill 300 insert geometry E-PL Max. chip thickness, hex (mm) Milling Feed per tooth, fz (mm) ap (mm) Min. 0.1 0.1 0.1 0.1 Start 0.15 0.2 0.2 0.2 Max. 0.2 0.25 0.25 0.25 0.5 0.31 0.46 0.50 0.57 1 0.23 0.33 0.36 0.41 1.5 0.19 0.28 0.30 0.34 2 0.17 0.25 0.27 0.30 2.5 3 3.5 4 0.23 0.25 0.28 0.23 0.26 0.24 0.23 E Drilling iC 8 10 12 16 3. Peripheral milling F The hex value varies depending on the cutter diameter and working engagement, the radial immersion of a cutter, ae/Dc. When this is smaller than 50%, maximum chip thickness is reduced relative to fz. Boring Feed can be increased by the modification value in the table below depending on the ratio, ae/Dc. Example: Dc 20 mm – ae = 2 mm, ae/Dc = 10% hex = 0.1 mm, fz = 0.17 mm/tooth. Tool holding/ Machines G Modification factor fz (mm/tooth): ae/Dc 1.0 1.16 1.25 1.4 1.66 2.3 Namnlöst-1 1 min. 0.1 0.10 0.12 0.13 0.14 0.17 0.23 start 0.15 0.15 0.17 0.19 0.21 0.25 0.34 max. 0.2 0.20 0.23 0.25 0.28 0.33 0.46 2009-08-31 09:29:34 Materials 50-100% 25% 20% 15% 10% 5% H hex (mm) I D 21 MTG09 Milling D1-D21.indd 21 Information/ Index Width of cut diameter ratio 2009-11-24 13:07:54 General turning A Parting and grooving B Threading C Milling D Milling – getting started Chip formation through cutter position The load on the cutting edge Each time a milling edge enters a cut, it is subjected to a shock load. The right type of contact between edge and material at the entry and also at the exit of a cut must be considered for successful milling. Down-milling In down-milling (climb milling), the cutting tool is fed with the direction of rotation. • Down-milling is always preferred wherever the machine tool, fixture and workpiece will allow. • In peripheral down-milling, the chip thickness will decrease from the start of cut, gradually reaching zero at the end of cut. This prevents the edge from rubbing and burnishing against the surface before engaging in the cut. • The large chip thickness is advantageous, and the cutting forces tend to pull the workpiece into the cutter, holding the cutting edge in the cut. Exceptions, when up-milling is preferred: • However, as the cutter tends to be pulled into the workpiece, the machine needs to handle the table-feed play using back-lash elimination. • If the tool pulls into the workpiece, feed is unintentionally increased which can lead to excessive chip thickness and edge breaking. • Up-milling may be advantageous when large variations in working allowance occur. Note: When using ceramic inserts in heat resistant alloys, up-milling is recommended, because ceramics are sensitive to impact at workpiece entry. Drilling E Boring F Tool holding/ Machines G In up-milling (conventional milling), the feed direction of the cutting tool is opposite to its rotation. • The chip thickness starts at zero and increases toward the end of the cut. Cutting forces tend to push the cutter and workpiece away from each other. • High tensile stresses, caused when the edge is leaving the workpiece, will often result in rapid edge failure. • The cutting edge has to be forced into the cut, creating a rubbing or burnishing effect due to friction, high temperatures and, often times, contact with a work-hardened surface caused by the preceding edge. All this reduces the tool life. • Forces, mainly radial, will tend to lift the workpiece from the table. • Thick chips at the exit from the cut will reduce tool life. • The large thickness and higher temperature at the exit will sometimes cause chips to stick or weld to the cutting edge, which will then carry them around to the start of the next cut, or cause momentary edge frittering. Work piece fixturs Feed direction of the tool places different demands on the workpiece fixture. During up-milling, it should resist lifting forces. During down-milling, it should resist pulling forces. Materials H Up-milling Information/ Index I D 22 Kopia av MTG09 Milling D22-D41.indd 22 Namnlöst-1 1 2010-01-14 13:05:28 A General turning Milling – getting started Chip formation through cutter position The cutting edge in a radial direction engages with the workpiece in three different phases: 1. Entrance into cut 2. Arc of engagement in cut 3. Exit from cut Parting and grooving B Threading C ϕ = +30° ϕ = –30° ϕ = 0° • The least sensitive of the three cutting zones, when using carbide inserts. • Carbide handles the compressive stresses at the impact of entering well. E Drilling 1. Entrance into cut Milling D Boring F Namnlöst-1 1 ϕ = 0° ϕ = +30° 2009-08-31 09:29:34 G Tool holding/ Machines ϕ = –30° 2. Exit from cut H Materials • Exiting from the workpiece is the most sensitive of the three cutting zones. • A thick chip will often cause a drastic reduction in tool life when using carbide inserts. The chip lacks support at the final point of cut and tries to bend, which generates a tensile force on the carbide that can create a fracture on the edge. D 23 Kopia av MTG09 Milling D22-D41.indd 23 Information/ Index I 2010-01-14 13:05:30 General turning A Parting and grooving B 3. Arc of engagement in cut • The maximum possible arc of engagement is 180° (ae = 100% Dc) when slotting. • For finish milling, the arc can be very small. • The grade requirements are quite different, depending on the percentage of radial immersion, ae/Dc. • The larger the arc of engagement, the greater the heat transferred into the cutting edge. • With a large arc of engagement, CVD coated grades provide the best heat barrier. • With a small arc of engagement, the chip thickness is normally smaller, and the sharper edge on PVD coated grades generates less heat and reduced cutting forces. Large (max.) arc of engagement • Long time in cut • High radial forces • More heat generated • CVD coated grades Threading C Milling – getting started Small arc of engagement • Short time in cut and less heat => higher vc • Thinner chip => higher fz • Higher vc and fz can be applied • Sharp edges • PVD coated grades Milling D Drilling E F Boring Summary of cutter positions Tool holding/ Machines G • Avoid thick chip thickness on exit - always use down milling. • Do not position the cutter symetrically on the centre line. • By moving the milling cutter off the centre (to the left) a more constant and favorable direction of the cutting forces will be obtained, minimizing vibration tendencies. • The cutter diameter, Dc, should be 20-50% larger than the width of cut, ae. • Available spindle power must also be considered, because it also influences the choice of pitch. H • Cutter Dc should be +20–50% large than ae • Cutter on centre line can generate vibrations Materials • Position the cutter off-centre (to the left) to achive a thicher chip at entry. Information/ Index I D 24 Kopia av MTG09 Milling D22-D41.indd 24 2010-01-14 13:05:31 A General turning Milling – getting started Entering the component When the cutter is programmed to enter straight into the workpiece, thick chips will be produced at the exit until the cutter is fully engaged. This can dramatically reduce tool life, especially in harder steels, titanium and heat resistant alloys. B Parting and grooving Also, from a vibration point of view, it is essential to enter the workpiece smoothly. There are two ways to solve this problem: 1. Lower feed Reduce feed to 50% until the cutter is fully engaged. 2. Roll into cut Program a roll into cut in a clockwise motion (counter-clockwise will not solve the thick chip thickness problem). By rolling into cut, the chip thickness on exit is always zero, allowing for higher feed and longer tool life. C Threading Thick chip on exit of cut until cutter is fully engaged. Milling D E Keep cutter constantly engaged F In face milling, sharp changes of cutter direction generate thick chips on exit. Boring • Rolling around all corners should always be applied as a key step to provide a robust, optimized process. • Width of cut, ae, should be 70% of Dc to ensure maximum coverage of the corner. • Keep cutter constantly engaged. • Program around interruptions and holes when possible. Drilling Sharp changes of direction in a cut will cause the same problem as occurs when entering straight into the workpiece. Tool holding/ Machines G In peripheral milling, roll around external corners. Materials H Namnlöst-1 1 I Programme around holes and interruptions. D 25 MTG09 Milling D22-D41.indd 25 Information/ Index Keep cutter constantly engaged. 2009-11-24 11:17:24 General turning A Parting and grooving B Threading C D Milling – getting started Milling in corners Considerations Machining into corners requires careful considerations of the suitable arc of cutter engagement, and also of the appropriate feed rate. • When feeding the cutter into internal corners, the radial arc of engagement will increase and place extra demands on the cutting edge. • Often, the process becomes unstable, creating vibration and an insecure process. • Wobbling cutting forces often create undercutting of the corner. • There is also a risk for frittering the tool edges, or total tool break down. The problem ae 90% Dc ae 20% Dc Corner radius = 50% x Dc Taditional corner milling Solution – limit the arc of engagement Using a programmed radius (circular milling) to reduce the arc of engagement and a radial cut will reduce the vibration tendencies, which will allow higher depths of cut and feed rates. • Mill a bigger corner radius than stated in the drawing. This can sometimes be favorable, as it allows the use of a bigger cutter diameter in roughing, which maintains high productivity. • Alternately use a smaller Dc cutter to mill the desired corner radius. Roughing A programmed radius of 50% Dc is optimal. Solution No 1 ae 20% Dc ae 55% Dc Milling Corner radius = 75% x Dc Drilling E Finishing For finishing, it is not always possible to have such a large radius; however, the cutter diameter should be no larger than 1.5 x component radius (e.g. corner radius 10 mm = max 15 mm). Mill a bigger component radius Solution No 2 ae 20% Dc F ae 40% Dc Corner radius = 100% x Dc Boring Use a smaller cutter Tool holding/ Machines G Centre line or periphery feed A machine is designed for either centre line feed, vf, (without radius compensation) or periphery feed, vfm (with radius compensation). If the machine requires a centre line feed, and periphery feed is programmed instead (on machines without radius compensation), the fz value will become too high, with the subsequent risk of insert breakdown. Materials H Programming Information/ Index I Centre line, vf, or periphery feed, vfm. D 26 MTG09 Milling D22-D41.indd 26 2009-11-24 11:17:24 A General turning Milling – getting started Centre line feed programming The NC codes generated will program the centre of the cutter rather than the periphery. For straight line cutting (G1), the feed at the wall of the component, vfm, is the same as the programmed feed, vf, while the periphery feed around a radius (G2) will be higher than the tool centre feed. Therefore the table feed, vf, needs to be reduced to maintain the feed per tooth, fz. A reduction factor is found in the table, and is dependent on: • Cutting diameter to component radius – Dc/radm • Radial immersion – ae/Dc Without centre line feed reduction, fz will increase in corners. Parting and grooving B Threading C D With centre line feed reduction. Milling Centre line feed reduction Reduction factor value for feed in corners (k) E ae/Dc 0.05 0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95 2.00 0.22 0.34 0.40 0.45 0.48 0.53 0.60 0.67 0.75 0.86 1.80 0.30 0.34 0.42 0.46 0.50 0.53 0.60 0.67 0.75 0.86 1.60 0.44 0.42 0.44 0.49 0.53 0.56 0.60 0.67 0.75 0.86 1.40 0.55 0.54 0.54 0.52 0.56 0.59 0.62 0.67 0.75 0.86 1.20 0.63 0.64 0.64 0.64 0.62 0.65 0.63 0.71 0.75 0.86 1.00 0.71 0.72 0.72 0.73 0.74 0.62 0.77 0.79 0.83 0.86 0.80 0.78 0.79 0.79 0.80 0.82 0.83 0.85 0.87 0.89 0.94 0.84 0.85 0.86 0.86 0.87 0.88 0.90 0.91 0.93 0.96 0.90 0.90 0.91 0.92 0.92 0.93 0.94 0.95 0.96 0.98 0.20 0.95 0.96 0.96 0.96 0.96 0.97 0.97 0.98 0.98 0.99 vf reduced = k × vf F Boring 0.60 0.40 Drilling Dc/radm G Feed reduction prior to corner Tool holding/ Machines Reducing the feed before reaching the corner is especially essential when milling at high speeds. As the cutter is still feeding straight towards the end of the G1 line, the arc of engagement starts to increase. Therefore, the feed has to be reduced before the corner is reached, i.e. within the ln range that is 50% x Dc. H Materials A machine control with an advanced look ahead function will manage the changes in feed rate automatically. D 27 MTG09 Milling D22-D41.indd 27 I Information/ Index Reduce the feed at a distance: ln = 50% Dc 2009-11-24 11:17:25 General turning Milling – getting started Milling dry or with cutting fluid B The effect of cutting fluid Parting and grooving A • The temperature variations are exacerbated when the cutting edge goes into and out of cut. • The cutting edge is thus subjected to thermal shocks and cyclic stresses that can result in cracking and, in the worst case, can lead to a premature end to the tools effective life. • The hotter the cutting zone is, the more unsuitable the use of cutting fluid becomes. In finishing operations, the application of cutting fluid will not reduce the tool life as much as in roughing, due to the reduced level of heat generation. Threading C The milling operation is an inherently intermittent process. This causes the temperatures generated at the cutting edge to constantly fluctuate between various levels of hot (~1000°C) and cold. Thermal cracks on the cutting edge D Milling Dry milling extends the life of the cutting edge • In dry milling, temperature variations do take place, but remain within the design scope of the carbide grade. • Rough milling operations should allways be run dry. E Drilling Exceptions, when cutting fluid can be justified F • Finishing of stainless steel and aluminium: – to prevent smearing of metal particles into the surface texture. • Milling of heat resistant alloys at low cutting speeds: – to lubricate and to cool down the component. • Milling of thin walled components: – to prevent geometrical distortion. • Micro-lubrication systems, i.e. compressed air with small amount of special oil, can be applied to assist chip evacuation in deep cavities. Boring • Milling in cast iron: – to dampen and flush away dust for environmental, health and component quality reasons. G Tool holding/ Machines Compressed air +++ Oil mist ++ + In micro-lubrication systems the amount of “oil mist” is only a few ml of oil per hour and is evacuated via the normal, filtered ventilating system. Copious flow through Cutting fluid (-) Materials H External flow If milling has to be performed wet, cutting fluid should be applied copiously. Information/ Index I D 28 MTG09 Milling D22-D41.indd 28 2009-11-24 11:17:31 Surface generation Axially generated surface Corner radius (r) Parallel land (bs1) The face milled surface is generated by the parallel facet, bs. Depending on the axial tolerance and run-out of the cutter, the insert with the lowest position will create the surface finish. B As soon as the feed per rev. exceeds the width of this land, the axial run-out of the cutter will affect the surface profile. Radius (Rbo) Wiper land (bs2) Parting and grooving To generate a good surface, it is important to ensure that the feed per revolution (fn = fz x zn) is less than 80% of bs. Extra close pitch cutters increase the feed per revolution, The larger the diameter cutter, the greater the fn, requiring a larger bs. A General turning Milling – getting started Parallel land (bs1) C Threading For the best surface finish use: • Wiper inserts or milling inserts with bs at least 25% larger than fn • Cermet inserts for mirror finish • Cutting fluid to avoid smearing. Round inserts, or inserts with a large corner radius, although extremely productive, will not generate a high quality surface. The larger the cutter's diameter, the worse the surface finish. D Milling For more information about finish milling using wiper inserts, see Face milling, page D 64. Drilling E Radially generated surface When using an end mill, shoulder mill or a side and face mill cutter, a radial surface is generated. For more information, see Shoulder milling, edging, page D 51. Boring F G Tool holding/ Machines Sculptured surface generation When using a ball nose end mill, a sculptured surface is generated. For more information, see Profile milling, page D 78. Materials H D 29 MTG09 Milling D22-D41.indd 29 Information/ Index I 2009-11-24 11:17:33 General turning A Parting and grooving B Threading C How to reduce vibrations Vibrations can arise due to limitations in the cutting tool, the holding tool, the machine, the workpiece or the fixture. Longer overhang Decreased tool stability The cutting tool • For face milling, the direction of the cutting forces must be considered: – With a kr 90° cutter, the dominant forces focus in the radial direction. This creates deflection of the cutter at long overhangs; however, the small axial force is advantageous when millng thin walled/vibration sensitive components. – Cutters with kr 45° generate evenly distributed axial and radial forces. – Round insert cutters direct most of the forces up the spindle, particularly at small depths of cut. Also, the CoroMill 210 with kr 10° transmits the forces primarily into the spindle, which reduces vibrations generated due to long tool overhangs. • Choose the smallest diameter possible for the operation • Dc should be 20-50% larger than ae • Choose a coarse pitch and/or differential pitch cutter. • A cutter with a low weight is advantageous e.g, CoroMill Century with aluminium body. Decreased workpiece stability At long tool overhangs, use a small entering angle=high axial cutting force. With thin walled, unstable workpieces use a large entering angle = small axial cutting force. Milling D Milling – getting started Drilling E Boring F Tool holding/ Machines G The holding tool The Coromant Capto® modular holding tool system enables tools to be assembled to the required length, while maintaining high stability and smallest run-out. • Keep the tooling assembly as rigid and short as possible. • Choose the largest possible adaptor diameter/size. • Use Coromant Capto adaptors with oversize cutters to avoid reduction adaptors, see picture. • For small milling cutters, use a tapered adaptor if possible. • In operations where the final pass is located deep in the component, change to extended tools at pre-determined positions, see picture. Adapt cutting data for each tool length. • For spindle speeds over 20 000 rpm, use balanced cutting and holding tools. Oversized cutters allow the largest possible coupling size. Always use the shortest possible tool length. Extend length succesively. H Materials Silent Tools dampened milling cutters For overhangs greater than 4 times the tool diameter, vibration tendencies can become more apparent, and Silent Tools damped cutters can dramatically improve the productivity. For more information, see Tool holding, Chapter G. Information/ Index I D 30 MTG09 Milling D22-D41.indd 30 2009-11-24 11:17:42 A General turning Milling – getting started The cutting edge To minimize the cutting force: • Choose a light cutting geometry, -L, with a sharp edge, and a grade with a thin coating. • Reduce cutting forces by using inserts with small corner radii and small parallel lands. Parting and grooving B Sometimes adding more damping to a system can decrease the vibration tendencies: • Use a more negative cutting edge geometry and a slightly worn cutting edge. C D Milling • Always position the cutter off-centre in relation to the milled surface. • With kr 90° long edge cutters or end mills use low radial immersion – max ae = 25% Dc and high axial cut – max ap = 100% De. • In face milling, use a small depth of cut, ap, and high feed, fz, with round inserts or high feed cutters with small entering angles. • Avoid vibrations in corners by programming a large path radius, see milling of corners, page D 26. • If the chip thickness becomes too low, the cutting edge will rub rather than cut, causing vibration. In such instances, the feed per tooth should be increased. Threading Cutting data and tool path programming E The machine condition can have a large influence on vibration tendencies. Excessive wear on the spindle bearing or feed mechanism will result in poor machining properties. • Choose machining strategies and cutting force directions to take full advantage of the machine stability. F Each machine spindle has natural areas which are prone to vibration. The areas of stable cutting are described as stability lobes, and increase as the rpm increases. • Even small increases as low as 50 rpm, can move a cutting process from unstable, with vibration, to stable. Boring For weak fixturs, feed direction into machine table Drilling The machine tool Workpiece and its fixture Pass 2 Pass 1 Milling components with thin wall/base and/or when the fixture is weak. • The fixture should be close to the machine table. • Optimize the tool path and feed direction towards the machine's/fixture’s strongest node to obtain the most stable cutting conditions. • Avoid machining in directions where the workpiece is poorly supported. • Up-milling can reduce vibration tendencies when fixture and/or workpiece are weak in a specific direction. Pass 3 Pass 4 Pass 6 Pass 5 Pass 7 Pass 8 Tool holding/ Machines G H D 31 MTG09 Milling D22-D41.indd 31 I Information/ Index Note that the first step should be made at half the depth of the second, third, etc. For more detailed information, see Shoulder milling, page D 52. Materials finish allowance 2009-11-24 11:17:44 General turning A Parting and grooving B Threading C Milling D E Milling different materials – Steel milling P Steel milling The machinability of steel differs, depending on alloying elements, heat treatment and manufacturing process (forged, cast, etc.) For more detailed information about materials and classifications, see Materials, Chapter H. Cutting data recommendations, see Main catalogue. Main issues • In soft, low carbon steels, built-up edge and burr formation on the workpiece are the main issues. • In harder steels, the positioning of the cutter becomes more important to avoid edge chipping. Suitable cutters and inserts • Most CoroMill cutters are well suited for steel machining with a comprehensive assortment of insert grades and geometries. • Note, that CoroMill Century (with steel body) and CoroMill 790, originally developed for aluminium, also perform very well in finishing steel. • The only tools not suitable for steel are the AUTO-cutters dedicated for grey cast iron. • PL, PM, PH and WL, WM, WH geometries • The GC4200-series of MT-CVD coated grades are the basic choice. However, for smaller diameter cutters, below Dc 32mm, and for shoulder milling cutters, k=90°, grade GC1030 is the first choice. • In harder steels, use GC1030 and GC1010. Cutting speed vc m/min 400 350 300 250 GC1030 200 GC4230 150 Drilling GC4220 100 GC4240 GC4220 GC4230 GC1030 GC4240 GC4220 GC4230 GC1030 50 F 0 60 – 240 241 – 330 > 330 Boring Cutting speed and grade recommendations related to material hardness. Tool holding/ Machines G H Application hints All recommendations provided on the previous pages in Getting started are valid for steel milling. Materials Recommendations, such as positioning of the cutter to avoid a large chip thickness on the exit, and to always run dry without cutting fluid, should always be considered, especially in roughing operations. Information/ Index I D 32 MTG09 Milling D22-D41.indd 32 2009-11-24 11:17:47 Grade guideline – face milling Wear resistance/hardness Dry conditions Maximum productivity conditions. Improved wear resistance. PD performance. High vc and fz. C Edge line security Low vc and fz. Edge line security with low cutting data. Smearing materials. Low carbon steels. Adhesive wear. Built-up edge. Small Dc. Insert bulk toughness Threading Toughness First choice in average conditions Predictable choice in difficult conditions. Larger Dc. D Grade guideline – end milling CoroMill® 490, CoroMill® 390, CoroMill® 316 Wear resistance/ hardness Milling Dry and wet conditions B Parting and grooving Dry and wet conditions A General turning Milling different materials – Steel milling Maximum productivity when crater wear and PD-resistance are crucial wear mechanisms. E Drilling Productive choice, large engagements and high cutting data. First choice in good to average conditions. F First choice in good to difficult conditions. Boring Toughness CoroMill® Plura Wear resistance/hardness G Tool holding/ Machines Finishing in hardened steels, e.g. D&M applications H Materials General end milling, finishing, semi-finishing and roughing in all ISO groups Roughing in difficult conditions, tough edge behaviour D 33 MTG09 Milling D22-D41.indd 33 Information/ Index I Toughness 2009-12-06 09:34:54 General turning A Parting and grooving B Milling different materials – Stainless steel milling M Stainless steel milling The machinability of stainless steels differs, depending on alloying elements, heat treatment and manufacturing process (forged, cast, etc.) For more detailed information about materials and classifications, see Materials, Chapter H. For cutting data recommendations, see Main catalogue. C Threading Ferritic/martensitic Milling D Drilling E Boring F Tool holding/ Machines G Ferritic and annealed martensitic stainless steels have a machinability that is comparable to low alloyed steels, and therefore, the recommendations for steel milling can be used. Austenitic and duplex stainless Material Classification: M1.x, M2.x and M3.x Edge chipping on the insert. Burr formation and bad surface finish. Main issues • The dominant wear criteria when milling austenitic and duplex stainless steels are: chipping on the edges due to thermal cracks, notch wear and built-up edge/smearing. • On the component, burr formation and surface finish problems are the main issues. Suitable cutters and inserts • Most CoroMill cutters can be used in austenitic and duplex stainless steel simply by choosing a dedicated insert geometry and grade. • In face milling, CoroMill 245 and CoroMill 300 are more suitable than CoroMill 345 and CoroMill 200, due to the more positive cutter geometry. • Use cutters with round inserts or small entering angles to minimize notch wear. • Use positive insert geometries (-ML, -WL). • GC2030 (PVD) is the first choice. • GC2040 (MT-CVD) is the complementary grade for tough conditions and cast stainless steel, where abrasive wear dominates. • GC1030 (PVD) is the universal choice for mixed production (ISO P, M and S) • If thermal cracks appear, change to a harder/more wear resistant grade, i.e. from GC2040 to GC2030. • For CoroMill Plura, grade GC1630 is the basic choice and GC1640 is a complementary choice at an increased demand for toughness and an internal cutting fluid supply is needed. Thermal cracks due to cutting fluid Cutting speed vc m/min 300 250 GC1030 200 GC2030 150 GC2040 GC1030 GC2030 GC2040 100 50 0 Austenitic Duplex Materials H Material Classification: P5.x Information/ Index I D 34 MTG09 Milling D22-D41.indd 34 2009-11-24 11:18:02 A General turning Milling different materials – Stainless steel milling Application hints Roughing • Use high cutting speeds (vc = 150-250 m/min) to avoid built-up edge. • In roughing, always run dry, without cutting fluid, to minimize problems with thermal cracks. Parting and grooving B Finishing • In finishing, cutting fluid, or preferably mist coolant/minimal lubrication, is sometimes necessary to improve the surface finish. There are fewer problems with thermal cracks in finish milling, because the heat generated in the cutting zone is lower. • With a cermet grade, CT530, sufficient surface finish can be obtained without cutting fluid. • A feed, fz, that is too low can cause higher insert wear because the edge is cutting in the deformation hardened zone. Threading C D Milling CoroMill® indexable insert cutters Wear resistance/hardness Drilling E First choice F Boring Tough choice Toughness G CoroMill® Plura Tool holding/ Machines Wear resistance/hardness For finishing H Materials First choice Tough choice D 35 Information/ Index I Toughness General turning A Parting and grooving B Threading C Milling D Drilling E K Cast iron milling Cast iron can be divided into malleable, grey, nodular, compact graphite iron (CGI), and austempered ductile iron (ADI). For more detailed information about materials and classifications, see Materials, Chapter H. For cutting data recommendations, see Main catalogue. Grey cast iron Material Classification: K2.x Main issues • The dominant wear criteria when milling grey cast iron are abrasive flank wear and thermal cracks. • On the component, frittering at the cutter exit side of the workpiece, and surface finish problems are the main issues. Suitable cutters and inserts There are several cutter concepts that have been developed primarily for milling grey cast iron: • CoroMill 365 allround cutter. • AUTO R roughing cutter. • AUTO-AF adjustable finishing cutter. • AUTO-FS non-adjustable finishing cutter. CoroMill 245 cassettes are available for AUTO-AF cutter bodies as an alternative. • Wiper inserts, see page D 64, are available for all of the above cutter concepts. • Most other CoroMill cutters can also be used in grey cast iron simply by choosing a dedicated insert geometry and grade. • CoroMill 345 is a good choice for mixed production of steel and cast iron. • Use K-geometries -KL, -KM, -KH and -KW (wiper). • Grade recommendations for indexable insert cutters, see Application hints below. • For CoroMill Plura solid carbide endmills, grade GC1620, and for CoroMill 316 grade GC1030 are the basic choices. Typical insert wear Frittering on the component Boring F Milling different materials – Cast iron milling Application hints H Roughing • Preferably run dry, without cutting fluid, to minimize problems with thermal cracks. Use carbide inserts with thick coatings. GC3040 is the first choice and GC3220 an optimizer for higher speeds. Materials Tool holding/ Machines G • If workpiece frittering is a problem – check flank wear – lower the feed, fz, in order to reduce chip thickness. – use a more positive geometry, -KL Information/ Index I ➤ D 36 MTG09 Milling D22-D41.indd 36 2009-11-24 11:18:12 A General turning Milling different materials – Cast iron milling • If cutting fluid must be used to avoid dust, etc. choose the wet milling grades. K20W is the basic choice and K15W and GC3040 are complementary grades. • Coated carbide is always the first choice, but ceramics (CC6190) can also be used. Note that the cutting speed, vc, should be very high, above 800 m/min. Burr formation on the workpiece limits the cutting speed. No cutting fluid should be used. Finishing • Use carbide inserts with thin coatings, or, alternately, an uncoated carbide, e.g. GC3220 in dry and K15 W in wet conditions. • Cubic boron nitride (CB50) can be used for finishing at high speeds in grey cast iron. No cutting fluid should be used. B Parting and grooving ➤ C Material Classification: K3.x Ferritic and ferritic/perlitic nodular cast iron The machinability of ferritic nodular cast iron is very similar to that of low alloyed steel. Therefore, the milling recommendations provided for ISO P materials should be used regarding selection of tools, insert geometries and grades. The first choice grade is GC1020. Threading Nodular cast iron D Perlitic nodular cast iron Milling Is more abrasive, therefore ISO K grades are recommended. Cutter recommendations are the same as for grey cast iron; however, sharper, more positive insert geometries should be selected, for example –KX and –KL for AUTO-R cutters, to minimize burr formation on the component. 900 600 250 200 The first choice grade is GC1020. 150 GC1020 is the basic choice for both dry and wet conditions. An alternative for dry conditions is K20D, and for wet conditions K20W. 100 Cirular milling can be a very good alternative method to conventional cylinder boring in CGI. GC6190 CB50 Drilling Perlitic content less than 90% This type of CGI, which often has a perlitic structure of around 80%, is the most common being milled. Typical components are engine blocks, cylinder heads and exhaust manifolds. E GC3220 K20W GC1020 GC3040 K20D K20W F GC1020 K20W GC3040 GC1020 0 GCI NCI CGI ADI Boring Material Classification: K4.x Cutting speed vc m/min G Tool holding/ Machines Compact graphite iron (CGI) Austempered ductile iron (ADI) Material Classification: K5.x H Roughing is normally carried out in the non-hardened condition and can be compared with milling of a high alloyed steel. Materials The finishing operation, however, is performed in the hardened material, which is very abrasive. This can be compared with milling of hard steels, ISO H. Grades with high resistance against abrasive wear are prefered. GC1020 is the first choice for both dry and wet conditions, the complementary grade for harder ADI-materials is GC1010. In comparison with NCI, the tool life in ADI is reduced to approx. 40%, and the cutting forces are approx. 40% higher. D 37 MTG09 Milling D22-D41.indd 37 Information/ Index I 2009-11-24 11:18:12 General turning A Parting and grooving B Milling different materials – Aluminium milling N Aluminium milling The machinability of aluminium differs primarily depending on the Si-content. Hypo-euthectic is the most common type, with a Si-content below 13%. The ISO N material group includes not only aluminium, but also magnesium, copper and zinc based alloys. For more detailed information about materials and classifications, see Materials, Chapter H. For cutting data recommendations, see Main catalogue. Aluminium with Si-content below 13% D Main issues • The dominant wear criteria are built-up edge/smearing on the edges, leading to burr formation and surface finish problems. • In cast aluminium sand inclusion can sometimes be a problem. • Good chip formation and evacuation are crucial for avoiding scratch marks on the component surface. Milling Threading C Drilling E Suitable cutter concepts Cutters developed primarily for milling of aluminium are: • CoroMill Century • CoroMill 790 • CoroMill Plura R216.32, R216.33 and R216.42 Most other CoroMill cutters can be used in aluminium simply by choosing a dedicated insert geometry and grade. CoroMill 790 dedicated for aluminium. CoroMill Century for face milling of aluminium. PCD-tipped insert, CoroMill Century Choose positive insert geometries with sharp edges • Use uncoated carbide grades (H13A, H10) when Si-content is below approx. 8% • When the Si-content is above approx. 8%, PCD-inserts (CD10) normally provide better machining cost efficiencies. Boring F Material Classification: N1.1-3 Tool holding/ Machines G • Unlike most other milling applications, cutting fluid should always be used in aluminium to avoid smearing on the insert edges and to improve surface finish. • A higher cutting speed generally improves the performance and does not negatively effect tool life. • A hex value of 0.10-0.20 mm is recommended. Values that are too low can lead to burr formation. Warning: Make sure that the maximum rpm for the cutter is not exceeded! • Due to the high table feeds, a machine with ”look-ahead” function should be used to avoid dimensional errors. • Tool life is always limited by the burr formation or surface finish on the component. Wear on the insert is difficult to use as a tool life criteria. Cutting speed vc m/min 4000 CD10 3000 2000 1000 0 H10 H13A SiC < 8% SiC > 8% Materials H Application hints Information/ Index I D 38 MTG09 Milling D22-D41.indd 38 2010-01-27 10:40:12 Milling different materials – HRSA and titanium milling HRSA and titanium milling General turning S A Heat resistant super alloys (HRSA) fall into three material groups; nickel-based, iron-based and cobalt-based alloys. Titanium can be pure or alloyed. The machinability of both HRSA and titanium is poor, especially in the aged condition, which imposes particular demands on the cutting tools. For more detailed information, see Materials, Chapter H, and application guide ”Heat resistant super alloys”, order No. C-2920:24, or ”Titanium machining”, order No. C-2920:22. Parting and grooving B Threading C General recommendations D E Drilling Suitable cutter concepts and inserts • Use round insert cutters (CoroMill 300, CoroMill 200) whenever possible to increase the chip thinning effect. • The CoroMill 690 long edge cutter is optimized for titanium machining. For cutting depths below 5 mm, the entering angle should be less than 45°. In practice, a round, positive-rake insert is recommended. • Cutter accuracy in both radial and axial directions is essential to maintain a constant tooth load and a smooth operation, and to prevent premature failure of individual cutter teeth. • The cutting edge geometry should always be positive with an optimized edge-rounding, to prevent chip adherence at the point where the edge exits the cut. • The number of cutting teeth actually in cut during the milling cycle should be as high as possible. This will provide good productivity if there is stability. Use extra close pitch cutters. Use round insert cutters to minimize notch wear F Stay in cut ae 30% of Dc Boring Main issues • Milling HRSA and titanium often requires machines with high rigidity, and high power and torque at low rpm. • Notch wear and edge chipping are the most common wear types. • High heat generation limits the cutting speed. Milling valid both for HRSA and titanium alloys G vc Tool holding/ Machines ae fz ap z H Changes have varying impacts on tool life; the cutting speed, vc, has the greatest impact, followed by ae, etc. D 39 Namnlöst-1 1 MTG09 Milling D22-D41.indd 39 I Information/ Index = Reduction in tool life as cutting parameter is increased Materials = Tool life 2009-08-31 09:29:34 2009-11-24 11:18:18 General turning A Parting and grooving B Threading C D Milling different materials – HRSA and titanium milling Cutting fluid Unlike milling in most other materials, coolant is always recommended to assist in chip removal, to control heat at the cutting edge, and to prevent the re-cutting of chips. High pressure coolant (70 bars) applied through the spindle/tools is always to be preferred instead of an external supply and low pressure. Exception: Cutting fluid should not be applied when milling with ceramic inserts due to the thermal shock. Cutting fluid supplied through the cutter is advantageous when using carbide inserts Insert/tool wear The two most common causes of tool failure and poor surface finishing are: • Excessive flank wear and edge line frittering. • Notch wear. • The best practice is to index the cutting edges at frequent intervals, to ensure a reliable process. • Flank wear around the cutting edge should not exceed 0.2 mm for a cutter with a 90 degree entering angle, like the CoroMill 490, or a maximum of 0.3 mm for round inserts. Milling Grade and geometry recommendations • GC2040 for roughing and difficult conditions • GC1030 for semi-roughing and finishing • Use positive geometries, like -ML and -PL • GC1620 is the basic choice for CoroMill Plura solid carbide end mills Typical insert wear Cutting speed vc m/min 100 50 GC1030 GC2040 0 ISO S Titanium GC1030 GC2040 ISO S HRSA Drilling E CoroMill 690 F Boring Ceramic inserts cutter for roughing HRSA Tool holding/ Machines G Ceramic insert cutter for HRSA. Note: • Ceramic inserts are NOT recommended in titanium • Cutting fluid should NOT be used with ceramic inserts. Materials H • Ceramic milling typically runs at 20 to 30 times the speed of carbide, although at lower feed rates (~0.1 mm/tooth), which results in high productivity gains. Due to intermittent cutting, it is a much cooler operation than turning. For this reason, speeds of 700-1000 m/min when milling are adapted, compared with 200–300 m/min for turning. • Ceramics have a high tendency for notching, which is why round inserts are primarily used to ensure a low entering angle. • Never use coolant. • Ceramics have a negative effect on the surface integrity and topography, and are therefore not used when machining close to the finished component shape. • The primary application for grade CC6060 (sialon) is milling Inconel 718 engine castings and oil drilling equipment, in both cases due to the high metal removal rates. • Maximum flank wear when using ceramic inserts in HRSA is 0.6 mm. • Cutter assortment – please contact your local Sandvik Coromant representative for ordering. Information/ Index I D 40 MTG09 Milling D22-D41.indd 40 2009-11-24 11:18:20 A This group contains hardened and tempered steels with hardness >45 – 65 HRC. For more detailed information about materials and classifications, see Materials, Chapter H. For cutting data recommendations, see Main catalogue. B H Parting and grooving Milling hard steel General turning Milling different materials – milling hard steel Typical components being milled are: • Tool steel inserts for stamping dies • Plastic moulds • Forging dies • Die casting dies • Fuel supply pumps C Threading Main issues • Abrasive flank wear on the insert. • Workpiece frittering. D E Stamping dies Gear housing Drilling • Most CoroMill cutters can be used in hardened steel simply by choosing a dedicated insert geometry and grade. • Use positive insert geometries with sharp edges. This will reduce the cutting forces and produce a softer cutting action. • Grade GC1010 is optimized for hard steels. • GC1030 is a complementary choice for unstable conditions, i.e. roughing in welded-on materials. • For finishing with CoroMill Plura, choose grade GC1610. Milling Suitable cutter concepts The CBN grade, CB50, can be used in finishing operations. F Boring Grade GC1010 is optimized for hard steels G Application hints Tool holding/ Machines • Run dry, avoid cutting fluid. • Trochoidal milling (see page D 121) is a suitable method, which enables high table feeds in combination with low cutting forces, generating low cutting edge and workpiece temperatures which are beneficial for productivity, tool life and component tolerances. • The machining strategy to run "light but fast" should also be applied in face milling, i.e. small depths of cut, both ae and ap. Use an extra close pitch cutter and relatively high cutting speeds. Materials H Trochoidal milling D 41 MTG09 Milling D22-D41.indd 41 Information/ Index I 2009-11-24 11:18:26 General turning A Shoulder milling – application overview Shoulder milling Application overview Parting and grooving B Shoulder/face milling Choice of tools D 44 C Threading How to apply D 46 Milling D Drilling E Boring F Choice of tools D 50 Tool holding/ Machines G Edging How to apply D 50 Materials H Information/ Index I D 42 MTG09 Milling D42-D59.indd 42 2009-11-24 11:28:18 A General turning Shoulder milling – application overview Shoulder milling Choice of tools D 45 B Parting and grooving How to apply D48 Threading C Milling D Drilling E F Boring Deep located Tool holding/ Machines G Materials H Milling Trouble shooting D 128 D 43 MTG09 Milling D42-D59.indd 43 Information/ Index I 2009-11-24 11:28:21 Shoulder face milling – choice of tools Shoulder face milling B Shoulder milling generates two faces simultaneously, which requires peripheral milling in combination with face milling. Parting and grooving General turning A Shoulder milling can be performed by traditional square shoulder cutters, and also by using end milling cutters, long edge cutters and side and face milling cutters. Due to these numerous options, it is essential to consider the operational requirements carefully to make an optimal choice. Threading C Achieving a true, ninety degree shoulder, is one of the most important requirements. D Milling Choice of tools Shoulder face milling CoroMill® 490 CoroMill® 390 CoroMill® 290 CoroMill® Century CoroMill® 331 20 – 80 40 – 200 40 – 250 40 – 200 80 – 315 Max. cutting depth (ap), mm 5.5 15.7 10.7 10 10.6 True 90° shoulder +++ ++ + + ++ P M K N S H P M K N S H Drilling E Boring F G Cutter dia. (Dc), mm Material Tool holding/ Machines Materials K N P M K N S H Shoulder milling cutters Shoulder face mills of conventional designs are often capable of milling “true”, 90 degree shallow shoulders. H P · First choice cutter is the accurate and light cutting CoroMill 490. This cutter provides the precision for milling deeper shoulders by using repeated passes with very limited cusps. · CoroMill 390 cutter product range offers a wide range of inserts, in particular a complete series of inserts with corner radii, which contribute to its success as a general purpose cutter. It is also the first choice cutter for shallow, heavy duty shoulder milling. · CoroMill Century is the first choice cutter for high speed finishing of aluminium, but is also suitable for milling other materials. · Many shoulder face mills are universal cutters, and can be used advantageously for making holes. They offer a good alternative to face milling cutters when milling axially deflecting surfaces or for milling close to vertical faces. · The side and face milling cutter, CoroMill 331, is a slot milling cutter than can also be used advantageously for milling wide, shallow shoulders. It can also be employed for some special purpose milling operations, such as back-face milling. Information/ Index I D 44 MTG09 Milling D42-D59.indd 44 2009-11-24 11:28:24 Shoulder milling – end milling cutters CoroMill® Plura CoroMill® 316 CoroMill® 490 CoroMill® 390 CoroMill® 390 Dampened CoroMill® 790 A General turning Shoulder face milling – choice of tools Cutter dia. (Dc), mm 10 – 20 10 – 25 20 – 80 12 – 40 20 – 40 25 – 100 Max. cutting depth (ap), mm 38 11 5.5 15.7 10 12 / 18 True 90° shoulder +++ +++ +++ ++ ++ ++ P M K N S H P M K N S P M K N S H P M K N S H P M K N S H N C Threading Material Parting and grooving B End milling cutters · CoroMill 790 is the first choice cutter for milling non-ferrous materials. · First choice for universal milling is the CoroMill 390. A vibration dampening version allows for effective machining of deep located surfaces. · CoroMill Plura solid carbide end mills are available in a huge number of versions for most milling conditions. D Milling The indexable insert and solid carbide end mills offer good solutions for shoulders requiring accessibility. E Shoulder milling – long edge cutters CoroMill® 690 Long edge cutter Coromant Finishing Long edge cutter Drilling CoroMill® 390 Long edge cutter 50 – 100 50 – 80 85 112 150 True 90° shoulder Material G +++ P M K N S H S P M K N S H Tool holding/ Machines Max. cutting depth (ap), mm 32 – 200 Long edge milling cutters Long edge cutters are generally used for milling deeper shoulders. · First choice for general roughing is CoroMill 390; under stable conditions, it is capable of heavy metal removal. · CoroMill 690 is the first choice cutter for milling of titanium. · Among cutters of this type, the light cutting Sandvik Coromant finishing long edge cutter produces a superior surface finish. Note: All the above cutters can perform edging operations and milling of ledge type shoulders. H Materials Cutter dia. (Dc), mm Boring F D 45 MTG09 Milling D42-D59.indd 45 Information/ Index I 2009-11-24 11:28:25 General turning A Parting and grooving B C Shoulder face milling – how to apply How to apply Application checklist and hints • Down-milling is always the first choice, and is especially important for shoulder milling due to the 90° entering angle. • Machining should be performed in a manner that directs the cutting forces towards the support points of the fixture insofar as this is possible. Up-milling can, therefore, be a favorable alternative in some cases. • Selection of cutter pitch is dependant on the stability of the entire system, including: the machine tool, workpiece and its clamping, as well as the workpiece material. Threading • In ISO 40 machines and smaller, coarse-pitch cutters are recommended, due to limited stability. • Coarse-pitch cutters are also recommended for machining components mounted high up on a cube fixture. For more information about workpiece rigidity and mounting stability, see Getting started, page D 31. D • The positioning of the cutter on the workpiece is extremely important and should receive extra attention. Milling • When Dc/ae >10, the feed, fz, should be adjusted in accordance with the hex value to achieve a good result and avoid edge breakdown. E • If the shoulder depth is smaller than 75% of the cutting edge length, the quality of the vertical surface does not normally require extra finishing. • Choose a tougher carbide insert grade than for face milling. • If CoroMill long edge cutters are used, the conditions are demanding, therefore, an even tougher grade may be required. • When vibrations occur, decrease vc and increase fz, check against the recommended hex value! F • Ensure that enough machine power is available for the chosen cutting data. See chapter I, for information about how to calculate this. Boring Drilling • The deeper the cut, the more important it is to choose a lower cutting speed in order to avoid vibrations. Tool holding/ Machines G Materials H Information/ Index I D 46 MTG09 Milling D42-D59.indd 46 2009-11-24 11:28:27 A General turning Shoulder face milling – how to apply Tool holding B Parting and grooving • Pay special attention to power requirements when taking large cuts, particularly with long edge cutters. • Tool mounting has the greatest influence on the milling result for cutters smaller than 50 mm. • The larger the cutting depth, the more important the size and stability of the coupling become: since the radial forces are considerable when using shoulder face mills, particularly long edge milling cutters. C • Coromant Capto couplings provide optimum stability and the smallest deflection for all types of cutters – particularly important with long or extended tooling. Threading • For more information about extended and vibration dampened adaptors, Silent Tools, see Getting started, page D 30 and Profile milling, page D 71. Milling D Rolling into cut E • Smooth entrances into the cut are essential for avoiding vibrations and extending tool life, particularly when milling shoulders. Drilling • Program the cutter to roll into cut; always generate a chip thickness on exit that is zero: together this will ensure both, higher feed and longer tool life. • This method is most suitable for applications in which you are milling around external corners, as it avoids sharp changes in the cut. For more information about rolling into cut, see Getting started, page D 25. F Boring • Keep the cutter engaged in a continuous cut. Tool holding/ Machines G Materials H D 47 MTG09 Milling D42-D59.indd 47 Information/ Index I 2009-11-24 11:28:27 Shoulder face milling– how to apply How to apply B This frequently used operation is generally performed by shoulder face mills and end mills. A shallow cut allows for a larger radial cut. Parting and grooving General turning A Often these cutters can replace face mills, in particular when the axial pressure on the component is a limitation, and when there is a demand for accessibility close to vertical faces or fixture sections. • Oversized shoulder cutter options provide for optimal accessibility when milling shallow shoulders located deep. • An extra robust version of the CoroMill 390 shoulder cutter is, under stable condition, capable of heavy removal rates. It also functions reliably under demanding conditions, like milling through interruptions. Threading C Milling of shallow shoulders D Milling of deep shoulders Milling Use repeated passes with shoulder face mills and end mills Drilling E Boring F Tool holding/ Machines G To minimize surface errors, such as scallops and transition-edges between the passes, a high precision cutter that is able to produce true 90º shoulders is an absolute requirement. If shoulder depth is smaller than 75% of the cutting edge length, the quality of the vertical surface does not normally require extra finishing. Use a single pass with a long edge milling cutter The long edge cutter is a good solution for deeper, larger and usually heavier shoulder milling applications: • High metal removal capacity. • Generally used for rough milling, as the resulting surface texture is characterized by side milling at high feed rates. These cutters make demands on: • Stability • Spindle condition • Chip evacuation • Tool holding • Power. Radial forces are considerable making this a tough side milling application. H Shorter long edge cutters are suitable for: • Radially large but shallow shoulders. • Full slotting at a depth equal to the diameter, which can make up for machine limitations. Materials Longer versions are intended for: • Milling of shoulders with moderate radial depth. • Edging in powerful, stable machines. Information/ Index I D 48 MTG09 Milling D42-D59.indd 48 2009-11-24 11:28:28 A General turning Shoulder face milling – how to apply Milling of shoulders located deep • Oversized shoulder cutter options provide for optimal accessibility in milling shallow shoulders located deep. For those shoulders that are located at even larger depths, use extensions with the Coromant Capto coupling. B Parting and grooving • Long edge cutters are also available in oversized versions to be used for deeper shoulders located deep. However, the radial depths of cut are more limited. Threading C Milling D E Milling of shoulders using side and face milling cutters Drilling Side and face milling cutters are also used for milling shoulders, particularly if the configuration is narrow yet radially wide. These cutters are often the only possible solution for back-facing of hidden shoulders and faces. F Left Boring Right R331.52 L331.52 R331.52 L331.52 L331.52 R331.52 G Tool holding/ Machines L331.52 H Materials R331.52 The right choice of a CoroMill 331 cutter for facing and back-facing in right and left-hand spindles. D 49 MTG09 Milling D42-D59.indd 49 Information/ Index I 2009-11-24 11:28:28 Edging – choice of tools Edging - peripheral milling B Machining an edge is really a side milling operation applied in contouring tool passes. Side milling and edging are options of peripheral milling. Parting and grooving General turning A Threading C Milling D • Thin edges are generally produced by end milling cutters, while deeper or thicker edges are generated by end mills using repeated “shoulder milling” passes, or by long edge cutters in a single pass. • Shoulders with depths of twice the diameter are effectively machined using long edge milling cutters or CoroMill Plura solid carbide cutters. For such deep shoulders, or thick component edges, a radial depth of cut of 0.5 times the diameter is recommended. • Side and face milling cutters can also be used for edging or peripheral milling. • A large helix ensures a sufficient number of teeth in cut and a smooth cutting action for edging at small radial cutting depths. • A close pitch or extra close pitch type of cutter is especially suitable for edging. This is also true when milling thinner edges or shallow ledge type shoulders using 90º end mills. Drilling E Choice of tools Boring F Tool holding/ Machines G H How to apply Application checklist and hints • A critical factor in peripheral milling is achieving a suitable feed per tooth, fz. • The feed value, fz, has to compensate for the cutter engagement, which influences the chip thickness, see Getting started, page D 20. • Feed per tooth, fz, should be multiplied by the modification factor. • This will give a higher feed rate with a smaller arc of engagement, and at the same time ensure that the chip thickness is large enough. Materials • However, the modification factor may not always be fully applicable: surface texture and climbing tendencies may limit the feed rate. Information/ Index I D 50 MTG09 Milling D42-D59.indd 50 2009-11-24 11:28:30 Surface texture – radially generated As mentioned, surface texture and climbing tendencies may limit the feed rate, especially when the radial depth of cut is small. h= fz2 4×D B Parting and grooving When using the side of an end mill to mill a profile, a series of ‘cusps’ are generated. The height of the cusp, - h, is determined by: • Cutter diameter, Dc • Feed per tooth, fz • Tool indicator reading of the run-out, TIR. C When there is no run-out in the cutter, the height of the cusp, h, will be equally high and can be calculated using the formula: Threading Indexable insert cutters will always have a higher TIR than solid carbide cutters. Also, the larger the cutter diameter, the greater the number of teeth, which increases the distance between the high and low spots of the cusp. A General turning Edging – how to apply For best surface finish: • Use a solid carbide CoroMill Plura or CoroMill 316. • Use a high precision power chuck (CororGrip or HydroGrip) with Coromant Capto coupling. • Use the shortest possible overhang. D Milling Feed recommendation (disregard hex): • Indexable insert cutters, start value fz = 0.15 mm/tooth • Solid carbide cutters, start value fz = 0.10 mm/tooth E F Boring When there is a run-out in the cutter, the feed per tooth, fz, and consequently the height of the cusp, h, will vary depending on the TIR. Drilling Note: The worst surface quality is achieved if only one cutting edge generates the surface, due to bad run-out of the cutter. G Profile depth/cusp height Rt = Tool holding/ Machines Rt = h fz2 4×D H fz fz run-out I Surface with and without run-out. D 51 MTG09 Milling D42-D59.indd 51 Information/ Index For information about axial edging using face milling cutters, see Face milling, page D 59. Materials For more information about cutter size, engagement and position relative to the workpiece, chip formation and rolling into cut, see Getting started, page D 22. 2009-11-24 11:28:31 Shoulder milling – how to apply Shoulder milling of thin and deflecting walls B • Machining strategies for thin wall sections will vary, depending on height and thickness of the wall. Parting and grooving General turning A C • The number of passes will be determined in all cases by the wall dimensions and the axial depth of cut. • Consider stability of both the cutter and the wall. • Use of high speed techniques, i.e. small ap/ae and high vc, facilitates milling of thin walls, as they reduce the time of tool engagement and consequently, the impulse and the deflection. • Down-milling should be applied. Threading • Equal methods are used for milling aluminium and titanium. Milling D Small height to thickness ratio <15:1: E • Machine one side of the wall in non-overlapping passes. "Thinwalls" • Repeat on the opposite side. Drilling • Leave an allowance on both sides for subsequent finishing. Boring F Tool holding/ Machines G Moderate height to thickness ratio <30:1 "Waterline" milling: • Alternate sides, machining to given depths, in nonoverlapping passes. Alternately Step support milling: • A similar approach, but overlap between passes on opposite sides of the wall: this provides more support at the point being machined. The first pass should be at a reduced depth of cut, ap/2. • In either case, leave an allowance on both sides for subsequent finishing of 0.2 – 1.0 mm. H Materials The passes should be made in a zig zag path. Information/ Index I D 52 MTG09 Milling D42-D59.indd 52 2009-11-24 11:28:32 A General turning Shoulder milling – how to apply Very large height to thickness ratio >30:1 In addition to alternating sides of the wall while machining, approach the desired wall thickness in stages, using a "christmas tree" routine. Pass 2 • Move down the wall in this stepwise manner. Parting and grooving B • The thinner section is always supported by thicker sections below them as they are machined. Pass 1 Pass 3 Pass 4 Pass 6 Pass 5 C Thin walls Waterline Threading >30:1 Step support D Pass 1 Pass 5 Pass 2 Pass 6 Pass 3 Pass 2 Pass 1 Pass 2 Pass 3 Pass 4 Pass 4 Pass 6 Pass 5 Pass 6 Pass 7 Pass 8 Pass 8 Pass 3 Pass 5 Milling Pass 4 Pass 1 Pass 7 E Pass 9 <15:1 <30:1 Finishing allowance Finishing allowance Drilling Finishing allowance Shoulder milling of thin walled base F Machining thin bases: • Use circular ramping at the centre of the base area to required depth. Boring • Mill outwards in a circular ramping path from that point. If this involves milling a surface whose opposite side has already been machined: G • Use a tool with a minimum number of cutting edges. Tool holding/ Machines • Apply as little contact pressure to this side as possible. If the component has a hole at the centre of the base: • Leave a support leg in place when machining the first side. • Machine the second side. H Materials • Remove the support leg after both sides have been completed. D 53 MTG09 Milling D42-D59.indd 53 Information/ Index I 2009-12-06 09:09:59 General turning A Face milling – application overview Face milling Application overview Parting and grooving B General face milling Choice of tools D 57 C Threading How to apply D 58 Milling D Drilling E Heavy duty milling F Choice of tools D 62 Boring How to apply D 63 Tool holding/ Machines G Materials H Information/ Index I D 54 MTG09 Milling D42-D59.indd 54 2009-11-24 11:28:36 A General turning Face milling – application overview Parting and grooving B High feed milling Choice of tools D 60 How to apply D 61 Threading C D Milling Finishing with wiper inserts Choice of tools D 64 E Drilling How to apply D 65 F K See page D 36 N Boring Material optimized cutters See page D 38 Tool holding/ Machines G Materials H Milling Trouble shooting D 128 D 55 MTG09 Milling D42-D59.indd 55 Information/ Index I 2009-11-24 11:28:42 Face milling – choice of tools Face milling B Face milling is the most common milling operation and can be performed using a wide range of different tools. Cutters with a 45º entering angle are most frequently used, but round insert cutters, square shoulder cutters and side and face mills are also used for certain conditions. Parting and grooving General turning A Threading C D Overview of face milling cutters The diagram below shows the main application area for different cutter concepts, in terms depth of cut, ap, and feed per tooth, fz. Milling ap CoroMill 390 LE CoroMill 690 E CoroMill 245 CoroMill 345 Heavy duty cutters Drilling CoroMill 360 CoroMill 390 CoroMill 490 F Round cutters CoroMill 200 CoroMill 300 Boring CoroMill 210 45° cutters 90° cutters G Tool holding/ Machines fz Materials H Information/ Index I Direction of cutting forces generated by different entering angles. D 56 MTG09 Milling D42-D59.indd 56 2009-11-24 11:28:49 General face milling – choice of tools General turning General face milling A Choice of tools 45°cutters CoroMill® 245 CoroMill® 345 Sandvik AUTO • First choice for general purpose • Reduce vibrations on long overhangs • Chip thinning effect allows increased productivity 6/10 6 6 Cutter dia. (Dc), mm 32 – 250 40 – 250 80 – 500 Material P M K N S H P M K S H K CoroMill® 490 CoroMill® 290 CoroMill® 390 D Milling 90°cutters • Thin walled components • Weak-fixtured components • Where 90° form is required 5.5 10.7 10/15.7 Cutter dia. (Dc), mm 20 – 80 40 – 250 12 – 42/ 400 – 200 Material P M K N S H P K CoroMill® 200 CoroMill® 300 F Boring Round insert cutters P M K N S H Drilling E Max. cutting depth (ap), mm 7/8 Cutter dia. (Dc), mm 25 – 160 10 – 42/ 25 – 125 Material P M K N S H P M K N S H H Materials See page D 150. 10°cutters I See page D 60. D 57 Information/ Index 10 Max. cutting depth (ap), mm Tool holding/ Machines G 60°– 65°cutters MTG09 Milling D42-D59.indd 57 Threading C Max. cutting depth (ap), mm • General purpose cutter • Strongest cutting edge • Many edges per insert • Especially suitable for heat-resistant alloys, ISO S. • Smooth cutting action Parting and grooving B 2009-11-24 15:41:38 General turning A Parting and grooving B General face milling – how to apply How to apply Application checklist and hints • Consider machine tool stability, spindle size and type (vertical or horizontal) and available power. • Use a cutter diameter that is 20 to 50% larger than the workpiece. C Threading • Consider maximum chip thickness when positioning the cutter for optimum feed. • Position the cutter off centre to produce the thinnest chip at exit. D Milling • Program the cutter to roll into the cut and reduce the feed to obtain a smooth entry. Roll into cut E Drilling • Apply down-milling for favourable chip formation, i.e. thick to thin chip. • Avoid entries and exits through tool path programming. Boring F • Frequent entering and exiting the workpiece should be avoided if possible. It can create unfavorable stresses on the cutting edge, or cause dwell and chatter tendencies. It is recommended that you program a tool path that keeps the milling cutter in full contact, rather than performing several parallel passes. When changing direction, include a small radial tool path to keep the cutter moving and constantly engaged. Tool holding/ Machines G Intermittent face milling of surfaces with interruptions • If possible, avoid milling over interruptions (holes or slots). Such intermittent cuts are demanding on the cutting edges as they cause multiple entries and exits. • Alternately, reduce the recommended feed rate by 50% over the workpiece area that contains the interruptions. Materials H Keep cutter constantly engaged. Namnlöst-1 1 Avoid milling over interruptions. Information/ Index I ➤ D 58 Namnlöst-1 1 MTG09 Milling D42-D59.indd 58 2009-11-24 11:28:51 A General turning General face milling – how to apply ➤ Face milling of thin-walled and deflecting sections • Consider the direction of the main cutting forces in relation to the stability of the workpiece and the fixture. • When milling axially-weak components, use a 90° shoulder milling cutter, as it directs the major portion of the cutting forces in an axial direction. • Alternately, use a light-cutting, face milling cutter. • Avoid axial depths of cut that are smaller than 0.5–2 mm to minimize axial forces. • Use a coarse-pitched cutter to obtain the smallest possible number of edges in cut. • Use sharp, positive (-L) edges to minimize cutting forces. Parting and grooving B Threading C The hints summerized above are more thoroughly described in Getting started, see pages D 20–D 31. D Edging of thin sections using face milling cutters Milling • The cutter should be positioned off centre for face milling operations on the edges of thin sections. The cut becomes smoother and the cutting forces are directed more uniformly along the wall, which reduces the risk of vibration. • Select a cutter pitch for these operations that maintains more than one insert in the cut at all times. • Use the lightest insert geometry possible (light instead of medium, or medium instead of heavy). • Select a smaller insert radius and shorter parallel land to lower the risk of vibration in thin-walled components. • Use low cutting data, small cutting depth, ap, and low feed/tooth, fz. Drilling E Boring F Tool holding/ Machines G Materials H For more information about cutter size, engagement and position in relation to the workpiece, and chip formation, see Getting started, page D 22–D 25. D 59 MTG09 Milling D42-D59.indd 59 Information/ Index I 2009-11-24 11:28:56 Hig feed milling – choice of tools High feed milling B Face milling with a very high feed per tooth (up to 4 mm/tooth) is possible when using cutters that have small entering angles or when using round insert cutters, due to the chip thinning effect. Although the depth of cut is limited to less than 2 mm, the extreme feed makes it a highly productive milling method. Parting and grooving General turning A Threading C Specific cutter concepts are dedicated for extreme high feed milling at small axial depths of cut. A small entering angle is the precondition required for applying a light and fast, high feed. D Choice of tools CoroMill® 316 CoroMill® Plura CoroMill® 200 CoroMill® 300 Milling CoroMill® 210 E Round insert cutters 1.3 1.3 10 7/8 Cutter dia. (Dc), mm 25 – 160 10 – 25 4 – 20 25 – 160 10 – 42/ 25 – 125 F Material P M K N S H P M K N S P M K N S H P M K N S H P M K N S H Boring Max. cutting depth (ap), mm 1.2 – 2 Drilling High feed cutters Tool holding/ Machines G CoroMill® 210 • The most productive high feed face mill with a 10° entering angle, allowing for very high feed per tooth, fz. CoroMill® Plura and CoroMill® 316 • More than double the feed rates compared to conventional end mills at small depths of cut, ap. • High precision tools optimized for high speed machining of hardened steel. • Roughing to semi-finishing of contours and asymmetrical configurations at extreme feed rates. Note: Do not exceed the maximum recommended ap for CoroMill 210, CoroMill Plura and CoroMill 316. For round insert and radius cutters, the ap value should be kept far below the maximum recommended value to allow high feed milling. CoroMill® 200 and CoroMill® 300 • Round insert cutters. • Increased chip thinning effect at reduced axial cut. • Smooth cutting action. • General purpose cutters for tough or light conditions. Materials H Information/ Index I D 60 MTG09 Milling D60-D79.indd 60 2009-11-24 11:37:08 Hig feed milling – how to apply General turning How to apply A Cutters with a small entering angle B Parting and grooving Maximum chip thickness is dramatically reduced by a low entering angle. This allows extremely high feed rates to be used without over-loading the inserts. For CoroMill 210: • This is true despite the limited depths of cut allowed by the ten degree entering angle; maximum 2.0 mm with the 14 mm insert, and 1.2 mm with the 9 mm insert. • In very favorable conditions, a feed per tooth, fz, of up to 4 mm/tooth can be used, and metal removal rate values (Q) up to 1400 cm³/min can be achieved. C CoroMill 210 iC Dimensions, mm D Uncut material iC R b ap x 9 2.5 7.05 1.2 0.79 14 3.5 12.0 2.0 1.48 Milling As always, the feed rate has to be reduced and adapted depending upon specific conditions and to avoid vibrations, which can damage the inserts. Threading Note: Avoid machining all the way against a 90° shoulder, because the positive effect of a low approach angle will be lost, i.e. the depth of cut will dramatically increase. E Drilling When using the CoroMill 210 in high feed applications, the same cutting data can be programmed as would be used for a round insert cutter with an insert radius R, see table. Round insert cutters When using high feed milling techniques with a round insert cutter, such as CoroMill 200 or CoroMill 300, the depth of cut should be kept low (max. 10% of insert diameter, iC, otherwise the chip thinning effect is reduced and the feed has to be decreased, see illustration. F Boring Note: When using round insert cutters, it is important to reduce the feed when approaching a wall/shoulder, because the depth of cut suddenly increases. Strong inserts for general roughing • The best performance is achieved when the depth of cut is smaller than 25% x insert diameter, iC. G Tool holding/ Machines Chip thickness, hex, varies with round inserts and depends on the depth of cut, ap. H Materials Namnlöst-1 1 On round inserts, the chip load and entering angle vary with the depth of cut. D 61 Information/ Index I Namnlöst-1 1 MTG09 Milling D60-D79.indd 61 2009-11-24 11:37:08 Heavy duty face milling – choice of tools Heavy duty face milling B These applications include rough milling of heavy forged or hot rolled material blanks, castings, and welded structures in large gantry mills and powerful milling machines, or machining centres. Parting and grooving General turning A Threading C Milling D Large amounts of material have to be removed, generating high temperatures and high cutting forces, which places specific demands on the milling inserts: • Heavy loads on the main edge at full depth of cut. • Wear at the corner by the abrasive scale when cutting depth approaches zero. A 60º entering angle is optimal for a heavy duty milling cutter. This design provides: • Good depth of cut capacity, relatively even cutting forces and a chip thinning effect that allows for high feed rates. • The axial allowance of the design allows the insert to have a generous parallel land, which generates good surface finishes. Choice of tools E CoroMill® 245-18 T-Max 45 CoroMill® 390-18 CoroMill® 300-20 60° 45° 45° 90° Round inserts Max. cutting depth (ap), mm 13 / 18 10 12 15.7 10 Cutter dia. (Dc), mm 160 – 500 32 – 250 100 – 400 40 – 200 66 – 200 Material P M K S P M K N S H P M K H P M K N S H P M K S H Drilling CoroMill® 360 Boring F Entering angle (kr), mm Tool holding/ Machines G CoroMill® 245, insert size 18 • A medium duty face mill that provides the lightest cutting ability. • Capable of cutting depths of 6–8 mm within a feed range of 0.2 – 0.6 mm. • First choice face mill for tough conditions in larger machining centres. • Can be used with wiper inserts for milling surfaces with good finishes. Materials H CoroMill® 360 • Designed for efficient tool handling, which results in short down-time and secure, quick insert indexing in the machine. • Depth of cut capability up to 18 mm, for good metal removal and machining of uneven, wavy surfaces. • High productivity – feed rates of 0.4 – 0.7 mm per tooth. • Generous parallel land for good semi-finishing results. • Strong insert corner to resist abrasive surface scale at small depths of cut. • Cutter strength, for security in very demanding cuts. Information/ Index I D 62 MTG09 Milling D60-D79.indd 62 2009-11-24 11:37:10 CoroMill® 300, insert size 20 A medium duty cutter with strong edges for tough conditions, like milling through scale and interruptions. The round insert geometry provides a smooth cutting action. Eight cutting edges can be utilized under favourable conditions. Maximum depth of cut is 10 mm. The maximum recommended chip thickness varies widely up to 0.55 mm per tooth, depending on the insert geometry and depth of cut. For complete information, see page D 162. T-Max 45 A 45° high performance face mill, primarily designed to handle demanding conditions in general, and operations involving long spindle overhang, where the feed per insert is limited by vibration tendencies. • Depth of cut capability up to 12 mm and feed range up to 0.5 mm allow for efficient metal removal. • Thick inserts with 2 mm of parallel or wiper land, which can be axially adjusted, make this cutter a reliable roughing tool; although it is also capable of finish milling. • Spring loaded insert clamping mechanism for easy handling and rapid insert indexing. General turning CoroMill® 390-18 First coice for medium duty face and shoulder milling. A B Parting and grooving Heavy duty face milling – how to apply Threading C D How to apply Milling Application checklist and hints Entrance into cut E Because of the tough conditions common in heavy duty milling, entrance into cut is often critical; it is preferable that it take place progressively. • If possible, program the tool path for rolling into cut. • If not, reduce the feed until the cutter is fully engaged. Drilling Cutter position and size In heavy duty milling, where many passes often have to be performed to mill a large surface, it is important to follow the recommendations regarding: • Cutter position and engagement • Cutter size in relation to machine tool capacity • Tool path, to avoid unfavorable exits F Boring For recommendations, see Getting started, page D 22. Be observant of high temperatures Demanding, heavy duty milling generates high temperatures. When magnetic tables are used to clamp the component, the large volumes of chips that are produced will often be retained around the cutter. Consequences include interrupted or partial chip evacuation, and re-cutting of chips, which are hazardous for tool life. To avoid this, keep the working area free of chips. Tool holding/ Machines G H Prevent the vulnerable insert corners from rubbing against abrasive skin and scale by increasing the depth of cut to move the surface contact point to the stronger main edge of the insert. Materials Note: When mounting indexing inserts with cutter, use gloves to avoid inconvenience or injury due to heat. D 63 MTG09 Milling D60-D79.indd 63 Information/ Index I 2009-11-24 11:37:13 Finishing with wiper inserts – choice of tools Finishing with wiper inserts B Excellent surface finishes can be achieved with standard inserts in combination with one or more wiper inserts. Wiper inserts work most usefully at a high feed per revolution, fn, in larger diameter cutters with extra close pitch and setting facilities. Parting and grooving General turning A Threading C Feed per revolution can be increased approx. four times while still maintaining good surface quality. Wiper inserts can be used in milling in most materials to produce good surface textures – even under unfavorable conditions. Choice of tools CoroMill® 345 CoroMill® 245 CoroMill® 365 CoroMill® Century AUTO-AF AUTO-FS Entering angle (kr), mm 45° 45° 65° 90° 75° 90° Max. cutting depth (ap), mm 6 10 6 10 1 8.1 Cutter dia. (Dc), mm 40 – 250 32 – 250 40 – 250 40 – 200 80 – 500 125 – 500 Surface finish (Ra) < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Material P K P M K N S H P K P M K N S H K K Milling D Drilling E Boring F Tool holding/ Machines G H CoroMill® 245 A wide range of wiper inserts are available for finishing of most materials. Larger diameter cutters of cassette design have facilities for axial setting. CoroMill® 345 A wiper insert is available that has two right-hand and two left-hand wiper edges. CoroMill® 365 Two wiper inserts are available • One with two right and two left-hand edges • One with an extra long wiper and with one right and one left-hand edge. AUTO-AF All cutter sizes have adjustable cassettes with insert seats suitable for either L-type or F-type wipers, with a longer wiper edge. Larger diameter cutters are of Cap design. AUTO-FS Larger diameter cutters are of Cap design and axially adjustable by using shims. A wiper insert with four edges is available. Materials Larger diameter Cap cutter versions are axially adjustable by using shims. CoroMill® Century A system for highly accurate setting allows the use of wipers in more than one insert seat in larger cutters, and in all insert seats in smaller cutters, which provides for extreme productivity while maintaining the high surface finish. The insert grades available cover wiper finishing of most materials. Information/ Index I D 64 MTG09 Milling D60-D79.indd 64 2009-11-24 11:37:15 Finishing with wiper inserts – how to apply General turning How to apply Mirror finish at high feeds • A wiper land protrudes below the milling inserts by approximately 0.05 mm, when mounted in cutters with fixed insert seats. For CoroMill cutters of cassette design, the wiper edge can be adjusted to this position with great accuracy. The protrusion subjects wiper inserts to greater loads than conventional inserts, which can lead to vibration. Therefore, wipers should be used for light machining at moderate cutting depths and in limited numbers. With one Wiper insert Standard inserts only Parting and grooving • When feed per revolution, fn, increases in large cutter diameters with a higher number of inserts, the need for wiper inserts becomes essential for maintaining surface finishes. • The cutter's axial run-out, which depends on spindle inclination, cutter size, mounting and the accuracy of its setting, influences the waviness of the machined surface. The crowned wiper land will compensate for this and produce a step-free surface. A feed per revolution limited to 60% of the wiper land will ensure this. B Surface roughness C fn = feed /revolution fn1 ≤ 0.8 x bs1 bs1 Feed fn fn2 ≤ 0.6 x bs2 Threading • When fn exceeds 80% of the length of the parallel land, bs, on standard inserts, a wiper edge will improve the surface. A D bs2 bs1 Milling • Depth of cut should be light to limit the axial forces and to reduce the risk of vibration. In finishing, the recommended axial depth of cut is 0.8 – 1.0 mm. E Drilling • Extra care is required when mounting a wiper insert to correctly position its long edge. F Boring Example: • The width of the parallel land, bs, on the insert is 1.5 mm. • There are 10 inserts in the cutter, and the feed per tooth, fz, is 0.3 mm. Feed per revolution, fn, will be 3 mm, i.e. twice the length of the parallel land. • To ensure a good surface finish, feed per revolution should be a maximum of 80% of 1.5 mm = 1.2 mm. • A corresponding wiper insert will have a parallel land with a width of approx. 8 mm. • Result: Feed per revolution could be increased from 1.2 mm to 60% of 8 mm = 4.8 mm. Note: Other limitations, such as machine power, must be taken into consideration. Tool holding/ Machines G Additional hints to achieve a “mirror finish” • Use high cutting speed and/or Cermet inserts to obtain a shiny surface. • Use cutting fluid or oil mist for sticky ISO M and S materials. • PVD-coated inserts with sharp edges and an ap of 0.5 – 0.8 mm produce the best surface finish. Materials H D 65 MTG09 Milling D60-D79.indd 65 Information/ Index I 2009-11-24 11:37:15 General turning A Profile milling – application overview Profile milling Application overview Parting and grooving B Profile Milling Choice of tools D 68 C Threading How to apply D 70 Milling D Drilling E Boring F Tool holding/ Machines G Materials H Information/ Index I D 66 MTG09 Milling D60-D79.indd 66 2009-11-24 11:37:17 A General turning Profile milling – application overview Turn milling Choice of tools D 81 B Parting and grooving How to apply D 82 Threading C Milling D Drilling E Blade milling – Profile and turn milling Boring F Tool holding/ Machines G Materials H Milling Trouble shooting D 128 D 67 MTG09 Milling D60-D79.indd 67 Information/ Index I 2009-11-24 11:37:21 Profile milling – choice of tools Profile milling B Profile milling covers multi-axis milling of convex and concave shapes in two and three dimensions. Parting and grooving General turning A Threading C The machining process should be divided into at least three operation types: • Roughing/semi-roughing • Semi-finishing • Finishing. Super-finishing, often performed using high-speed machining techniques, is sometimes required. Milling of remaining stock, so called rest milling, is included in semi-finishing and finishing operations. For best accuracy and productivity it is recommended to perform roughing and finishing in separate machines, and to use dedicated cutting tools for each operation. The finishing operation should be carried out in a 4/5-axis machine tool with advanced software and programming techniques. This can considerably reduce, or even completely eliminate, time consuming manual completion work. The final result will be a product with better geometrical accuracy and a higher surface structure quality. Milling D The larger the component and the more complicated the configuration to machine, the more important the process planning becomes. Drilling E F Choice of tools Roughing and semi-roughing cutters CoroMill® 316 CoroMill® 216 Boring CoroMill® Plura Tool holding/ Machines G H Design VFD corner radius BNE Cutter dia. (Dc), mm 4 – 20 1 – 20 Materials Max. cutting depth (ap), mm Information/ Index I Material BNE Corner radius BNE 10 – 25 10 – 50 38 13 44.6 P M K N S H P M K N S P M K N S H VFD = Variable flute depth BNE = Ball nose end mill D 68 MTG09 Milling D60-D79.indd 68 2009-11-24 11:37:24 A General turning Profile milling – choice of tools Roughing and semi-roughing cutters CoroMill® 300 CoroMill® 200 Parting and grooving CoroMill® 390 B CoroMill® 790 Design Radius Toroid Round Round Radius Cutter dia. (Dc), mm 12 – 200 10 – 42 25 – 125 25 – 160 25 – 54 40 – 100 7/8 10 12/18 P M K N S H P M K N S H N Max. cutting depth (ap), mm 40 – 200 P M K N S H D Milling Material 12 – 42 Threading C E Finishing and super-finishing cutters CoroMill® 316 CoroMill® 216F CoroMill® 790 Drilling CoroMill® Plura Cutter dia. (Dc), mm Max. cutting depth (ap), mm Material VFD corner radius BNE 4 – 20 1 – 20 BNE Corner radius BNE Radius G 10 – 25 8 – 32 25 – 54 40 – 100 38 13 4.8 12/18 P M K N S H P M K N S P M K N S H P M K N S H Tool holding/ Machines Design Boring F H Materials BNE = Ball nose end mill D 69 MTG09 Milling D60-D79.indd 69 Information/ Index I 2009-11-24 11:37:24 General turning A Parting and grooving B Threading C How to apply Application checklist and hints The profile of the component should be studied carefully in order to select the right tools and find the best suited maching method: • Define minimum radii and maximum cavity depth. • Estimate the amount of material to be removed. • Consider tool set-up and clamping of workpiece in order to avoid vibrations, see page D 30. • All machining should be performed on dedicated machines to achieve good geometrical accuracy on the profile. • By using separate, accurate machine tools for finishing and super-finishing operations, the need for time-consuming manual polishing can be reduced, or in some cases eliminated. • Some advanced programming may be necessary to obtain large savings. • Use CoroMill Plura end mill with high speed technique to machine near net shapes and achieve the best possible finish, see page D 75. • Roughing and semi-finishing of large components are, as a rule, most productively done with conventional methods and tooling. An exception is aluminium, for which high cutting speeds are also used for roughing. Vibrations – methods for their reduction E Vibration is an obstacle in milling deep profiles using long overhangs. Common methods to overcome this problem are to reduce depth of cut, speed or feed. Drilling Milling D Profile milling – how to apply Boring F • Use stiff modular tools with good run-out accuracy. • Modular tools increase the flexibility and possible number of combinations. • Use damped tools or extension bars when total tool length, from the gauge line to the lowest point of cutting edge, exceeds 4−5 times diameter at the gauge line. • Use extensions made of heavy metal, if bending stiffness must be radically increased. • Use balanced cutting and holding tools for spindle speeds over 20,000 rpm. • Choose the largest possible diameter on the extensions and adaptors relative to the cutter diameter. • 1 mm in radial difference between the holding and the cutting tool is enough. Use oversized cutters. • Plunge milling is an alternative method for milling with extra long tools, see Dedicated methods, page D 116. Tool holding/ Machines G Materials H Information/ Index I D 70 MTG09 Milling D60-D79.indd 70 2009-11-24 11:37:29 A General turning Profile milling – how to apply Extend tool length gradually To maintain maximum productivity in roughing operations, where the final pass is located deep in the component, it is important to work with a series of extensions for the cutter. B Parting and grooving • Start with the shortest extension, as longer extensions limit productivity and tend to generate vibration. • Change to extended tools at pre-determined positions in the program. The geometry of the cavity determines the point of change. • Adapt cutting data to each tool length to maintain maximum productivity. Threading C • When opening up a cavity, it is important to choose a method that minimizes ap, and also leaves a constant stock for the subsequent profile milling operation. • Shoulder face/end mills or long edge cutters will leave a stair-case stock that has to be removed. This generates varying cutting forces and tool deflections. The result is an uneven stock for finishing, which will influence the geome trical accuracy of the final shape. • Use of round insert cutters (CoroMill 300 or CoroMill 200) will generate smooth transitions between the passes and leave less stock in more even quantities for the profiling operation, resulting in a better component quality. • A third alternative is to use a high feed cutter (CoroMill 210) to open the cavity. This will also result in a small, and even constant, stock, due to the small depth of cut, i.e. small stair-case steps. E Drilling For more information, see page D 102. Methods for opening up and widening a hole. D Milling Opening up from a solid workpiece Round insert cutter High feed cutter – Larger and uneven stock remaining + Small stock remaining + Small stock remaining F Boring Square shoulder cutter Tool holding/ Machines G Materials H D 71 MTG09 Milling D60-D79.indd 71 Information/ Index I 2009-11-24 11:37:30 General turning A Parting and grooving B Contouring or copy milling tool paths? The traditional and easiest method for programing tool paths for a cavity is to use the normal copy milling technique, with many entrances and exits into the material. However, this means that powerful softwares, machines and cutting tools are used in a very limited way. An open minded approach to the choice of methods, tool paths, milling and holding tools is essential. Instead of using programming techniques that are limited to "slicing off" material at a constant Z-value, it is highly advan tageous to use contouring tool paths in combination with down-milling. The results include: • A considerably shorter machining time. • Better machine and tool utilisation. • Improved geometrical quality of the machined shape. • Less time-consuming finishing and manual polishing work. The initial programming work is more difficult and will take somewhat longer; however, this is quickly recouped as the machine cost per hour is normally triple that of a workstation. Threading C Profile milling – how to apply D Copy milling Favourable Common + Cutting speed control - ve − Heavy load on the insert centre point Milling Contour milling Drilling E F + Enabling HSM + High feed rates + Productivity + Long insert life Boring + Security − Reduced feed rates − Reduced tool life − Mechanical impact − Form errors − Longer programs and cutting time Tool holding/ Machines G For both contouring and copy milling, it is preferred to use a machine with software that has look ahead functions to avoid tool path deviations. Materials H Look ahead function Information/ Index I D 72 MTG09 Milling D60-D79.indd 72 2009-11-24 11:37:32 A General turning Profile milling – how to apply Contouring • Use a contouring type of tool path as, such “Waterline milling”, as the best method to ensure down milling. B Parting and grooving • Contouring with the periphery of the milling cutter often results in a higher productivity, as more teeth are effectively in the cut on a larger tool diameter. • If the spindle speed is limited in the machine, contouring will help maintain and control the cutting speed. • Contouring also creates fewer quick changes in the work load and direction. In high speed and feed milling, and in hardened materials, this is of specific importance as the cutting edge and the process are more vulnerable to any changes that can create differences in deflection or create vibration. C Threading • For good tool life, stay in the cut continuously, and for as long as possible. Note! Avoid cutting with centre of the tool when cutting speed is zero. Milling D Drilling E Tool path strategy F Helical contouring, three – five axes. Finishing Boring Z – constant contouring, two axes. Roughing to finishing Waterline milling Z - constant countouring Countouring in a ramping tool path Tool holding/ Machines G • Common when CAM- controlled maximum scallop function is available • Smooth changes of direction H • Easy programming • Wide tool choice • Good form accuracy and surface finish • Controlled scallop height • Constant engagement Materials • Smooth engagement and retraction • Short programs • Short tool D 73 MTG09 Milling D60-D79.indd 73 Information/ Index I 2009-11-24 11:37:37 General turning A Parting and grooving B Threading C Profile milling – how to apply Copy milling A copy milling tool path is often a combination of up- and downmilling, and requires a lot of unfavorable engagements and disengagements in the cut. • Use a feed speed control with a look ahead function. Otherwise, the deceleration will not be fast enough to avoid damages to the tool centre. Each entrance and exit means that the tool will deflect, leaving an elevated mark on the surface. • There will be a large contact length when the cutter hits the wall, with risk for deflection, vibration or tool breakage. The cutting forces and the bending of the tool will then decrease, and there will be a slight undercutting of material in the exit area. • When using ball nose end mills, the most critical area is at the tool centre, since the cutting speed is zero. Avoid using the tool centre area and apply point milling by tilting the spindle or the workpiece to improve the conditions. Conclusions: • Copy milling along steep walls should be avoided as much as possible. When plunging, the chip thickness is large and cutting speed should be low. • It is somewhat better for the cutting process to perform up-copying along steep walls as the chip thickness has its maximum at a more favourable cutting speed. • There is a risk of edge frittering at the tool centre, especially when the cutter hits the bottom area. Milling D Drilling E F Risk for gouging Up-copying: Maximum chip thickness at recommended vc. D&M 04 Application technology Down-copying: Large chip thickness at very low vc. Tool path strategy Boring G At bottom of cavity: Risk of frittering at tool centre. Form errors are common, especially when using high speed machining technique. 7. Copy milling  Surface errors  Unfavourable method Tool holding/ Machines 100 %  Reversing 100 %up and down milling 100 %  Alternating 50 deflection/ 20° forces % cutting 40 % 60 % 45° 45°  Frequent accelerations and H Materials CoroMill decelerations limits level of 90° productivity  Shortens tool life  Requires more manual labour Feed reduction to avoid shortened tool life Reversed up and down-milling will expose the tool to alternating deflection and cutting forces. By216-R reducing feed rate of the tool path, the risk for edge frittering is 216-FthePlura Plurain the 300 critical 200 sections 390 reduced, and a safer cutting process with longer tool life is echieved. Please note, click on any of the icons above to access the relevant product family. Information/ Index I D 74 MTG09 Milling D60-D79.indd 74 2009-11-24 11:37:37 A General turning Profile milling – how to apply Parting and grooving B Roughing Semi-finishing Threading C Finishing and super-finishing D Milling Constant stock allows near net shape milling A constant stock is one of the truly basic criteria for high and constant productivity in profile milling, especially when using high speeds. • The best quality in finishing is achieved when preceding operations leave as little and as constant an amount of stock as possible. • To reach maximum productivity in these operations, common in die and mould making, it is important to adapt the size of the milling cutters to specific operations. • The goal should always be to come as close as possible to the requirements specified for the final shape. It is often more favorable to de-escalate the sizes on different cutters, from bigger to smaller, especially in light roughing and semi-finishing, instead of using only one diameter throughout each operation. Drilling • Safe cutting process. Benefits with a constant stock • Some semi-finishing and practically all finishing operations can be performed partially manned, or even sometimes unmanned. • Impact on the machine tool guide ways, ball screws and spindle bearings will be less negative. F Boring • The primary goal is to create an evenly distributed working allowance, or stock, to obtain few changes in work load and direction for each tool used. E Tool holding/ Machines G Materials H D 75 MTG09 Milling D60-D79.indd 75 Information/ Index I 2009-12-06 09:27:14 General turning A Parting and grooving B Profile milling – how to apply True cutting speed If using a nominal diameter value of the tool when calculating the cutting speed of a ball nose or round insert cutter, the true cutting speed, vc, will be much lower, if the depth of cut, ap, is shallow. Table feed and productivity will be severely hampered. π × n × Dcap 1000 m/min Base calculations of cutting speed on true or effective diameter in cut, Dcap. Shoulder end mill C Round insert cutter Ball nose cutter Dc = 6 mm Threading vc = 250 m/min n = 13 262 rpm D vc = Dc = 6 mm vc = 250 m/min n = 36 942 rpm Dc = Dcap = 6 mm Dcap = D3 - iC + √ iC² - (iC - 2 × ap )² Dcap = 2.15 mm Milling Dcap = 2 × √ ap × (Dc - ap) Drilling E • When using a ball nose end mill, the most critical area of the cutting edge is the tool centre, where the cutting speed is close to zero, which is unfavorable for the cutting process. Chip evacuation at the tool centre is critical, due to the narrow space at the chisel edge. • Therefore, tilting the spindle or the workpiece 10 to 15 degrees is recommended, which moves the cutting zone away from the tool centre. - The minimum cutting speed will be higher. - Improved tool life and chip formation. - Better surface finish. Boring F Point milling – tilted cutter Tool holding/ Machines G CoroMill® Plura and CoroMill® 316 - centre cutting cutters Central part, z = 2 Materials H Information/ Index I Peripheral part, z = 4 Z=2 Z=4 To ensure four effective cutting edges, the cutter should be tilted approx. 10-15 degrees. D 76 MTG09 Milling D60-D79.indd 76 2009-11-24 11:37:42 Shallow cut Allows higher cutting speed, vc, and feed/tooth, fz When using a round insert or a ball nose cutter at a lower depth of cut, the cutting speed, vc, can be increased due to the short engagement time for the cutting edge. The time for heat propagation in the cutting zone becomes shorter, i.e. the cutting edge and the workpiece temperature are both kept low. Parting and grooving B Also, the feed/tooth, fz, can be increased, due to the chip thinning effect, see Getting started, page D 20. Shallow cut Threading C Example shallow cut: Non-tilted versus tilted cutter D This example show the possibilities for increasing the cutting speed when the ae/ap is small, and also the advantages of using a tilted cutter. Milling CoroMill Plura ball nose cutter Dc = 10 mm, grade GC 1610. Material: Steel, 400HB Cutting data recommendation for a deep cut ap - Dc/2 : vc = 170 m/min fz = 0.08 mm/r = hex • Semi-finishing ap = 2 mm Dc = 10 mm Dcap = 8 mm Dc = 10 mm Dcap = 8.9 mm vc = 300 m/min n = 11 940 rpm vc = 300 m/min n = 10 700 rpm hex = 0.08 mm fz = 0.12 mm/tooth zc = 2 fn = 0.24 mm/r hex = 0.08 mm fz = 0.12 mm/tooth zc = 4 fn = 0.48 mm/r vf = 2 860 mm/min vf = 5 100 mm/min A non-tilted cutter is not recommended for super- finishing Dc = 10 mm Dcap = 4.4 mm Feed per tooth, fz, is the same for both the non-tilted and the tilted cutter, but the effective No of edges, zc, differs near the centre as described on the previous page. • Super-finishing ae = 0.1 mm The cutting speed can be increased by the factor 3-5 due to the extremely short contact time: vc = 850 m/min n = 61 100 rpm vc = 5 x 170 = 850 m/min Note: In super-finishing a two teeth cutter zn = 2, should be used to minimize the run-out. With this extremely small ap, the fz will be limited by the surface finish demands. Therefore, hex must be disregarded. A good rule of thumb in super-finishing is to use approx. the same fz as the ae. G Namnlöst-1 1 hex = 0.02 mm fz = 0.12 mm/tooth zc = 2 fn = 0.24 mm/r H vf = 14 600 mm/min Materials vc = 300 m/min F Boring Tilted cutter (10°) Tool holding/ Machines Non-tilted cutter Drilling E Operation The speed can be further increased by approx. 75% due to the shallow cut and short engagement time: A General turning Profile milling – how to apply fz = 0.12 mm/r D 77 MTG09 Milling D60-D79.indd 77 Information/ Index I 2009-11-24 11:37:42 General turning A Parting and grooving B Generation of sculptured surfaces A ball nose cutter or a radius shaped cutting edge will form a surface with a certain cusp height, h, depending on: • Width, ae, of cut • Feed per tooth, fz. Other important factors are the dept of cut, ap, which influences the cutting forces and the tool indicator reading of the run-out – TIR. For best results: • Use high precision HydroGrip chucks with Coromant Capto coupling. • Minimize tool overhang. Threading C Profile milling – how to apply D Milling Down milling with a cutter tilted approx. 10° in two directions ensures a good surface finish and a reliable performance. Finishing and super-finishing If the feed per tooth is much smaller than the width and depth of cut, the surface generated will have a much smaller cusp height in the feed direction. It is beneficial to achieve a smooth, symmetrical surface texture in all directions, which can be easily polished afterwards, regardless of the polishing method selected. This is obtained when fz ≈ ae. Always use a tilted two teeth-cutter in super-finsishing to achive the best surface texture. Drilling E Roughing and semi-roughing Boring F Tool holding/ Machines G Materials H Information/ Index I Semi-roughing with fz much smaller than ae. Super-finishing with a tilted cutter and fz equal to ae. D 78 MTG09 Milling D60-D79.indd 78 2009-11-24 11:37:43 A General turning Profile milling Parting and grooving B C CoroMill® 390 Threading CoroMill® Plura Milling D Drilling E F CoroMill® 316 Boring CoroMill® 300 Tool holding/ Machines G Materials H I CoroMill® 216 D 79 MTG09 Milling D60-D79.indd 79 Information/ Index CoroMill® 300 toroid 2009-11-24 11:37:57 Turn milling – choice of tools Turn milling B Turn milling is defined as the milling of a curved surface while rotating the workpiece around its centre point. Parting and grooving General turning A Threading C D Eccentric forms or shapes that differ considerably from those that conventional milling or turning methods produce can often be turn milled. The method allows for high metal removal with superb chip control. • A cylindrical surface can be produced only when feeding the milling cutter in a radial direction during rotation. • By simultaneously moving the cutter in two directions, it is possible to produce eccentric surfaces, e.g. cams on shafts. • Movement in more than 2 axes requires a tool with ramping capabilities. • To machine a conical shape, 5 axes are required. • Turn milling of complex profiles, e.g. turbine blades, requires simultaneous movement in 5 (or 4) axes, 2 or 3 for the workpiece and 1 or 2 for the tool. Milling • It is possible to produce components, such as turbine blades, by feeding the cutter in more than 2 axes while simultaneously rotating the component. E Drilling Choice of method F Face turn milling – 4/5 axes Periphery turn milling – 3/4 axes Main method for external machining. Same principle as for circular milling/ramping, but with component rotating. Boring Used mainly for internal features. Tool holding/ Machines G Materials H + Short tool extensions + Smaller tool diameters/low torque + External/slender components + Profiling − Not a natural cylindrical surface − Internal. Information/ Index I + Internal machining + Cylindrical surface + Narrow slots + Thread milling + Roundness − Profiling − Larger diameters/high torque − Long overhangs. D 80 MTG09 Milling D80-D99.indd 80 2009-11-24 12:49:59 A Turn milling cutters for roughing B 90° end mill CoroMill® 390 Long edge CoroMill® 390LE 45° face mill CoroMill® 245 High feed CoroMill® 210 Parting and grooving Choice of tools General turning Turn milling – choice of tools Round insert CoroMill® 300 +++ ++ – + Width of cut – (ae) ++ ++ ++ – +++ Table feed – (vf) ++ + ++ +++ +++ Metal removal – Q (cm3/ min.) + +++ ++ + +++ Bottom cutting + – – – +++ Power/stability ++ – ++ + +++ Surface finish +++ + +++ – ++ Difficult materials + + ++ ++ +++ Rough to finish +++ + +++ – ++ D Milling ++ E Drilling Depth of cut – (ap) Threading C Turn milling cutters for finishing F 90° indexable insert end mill CoroMill® 390 90° indexable insert face mill CoroMill® Century Round insert CoroMill® 300 Boring 90° solid end mill CoroMill® Plura +++ +++ + Number of wipers 4 1 1 to full 0 Feed per tooth – + +(*+++) ++ Metal removal – Q (cm2/ min.) – + +(*+++) ++ Against shoulder +++ +++ +++ – Difficult material + + + +++ Narrow profile +++ + + – H Materials +++ * Only when cutting axially and fully loaded with wipers. I D 81 MTG09 Milling D80-D99.indd 81 Information/ Index Surface flatness Tool holding/ Machines G 2009-11-24 12:50:00 General turning A Parting and grooving B How to apply Cutter position - rectangular inserts/wiper In face turn milling, one wiper insert is used to generate the straight line contact between the cutter and the machined surface in order to create the cylindrical part of the component. Because the milled surface is convex, the wiper land has to be flat instead of crowned. To cover the full width of the cutter, the tool has to be placed with at least two offsets, first Ew1 during first revolution of the work piece and then moved to Ew2 for a second cut. Location of cutter Width of cut 1 = First cut 2 = Second cut Threading C Turn milling – how to apply Milling D E Cutter position - round inserts/non wiper For producing the flatest possible surface, a small diameter cutter with a width of cut, ae, less than 40% of the effective cutter diameter, Dc, is optimal. Drilling However, the ae needs to be increased in order to obtain the best productivity. This can be done by increasing: • Cutter diameter F To gain acceptable cusp height, the cutter needs to be offset from the centre. The amount of offset depends on the ae, and is taken from the diagram for the respective ae/Dc. Boring • Ratio of radial engagement – ae/Dc. Tool holding/ Machines G H 2009-08-31 09:29 Materials Namnlöst-1 1 Information/ Index I D 82 MTG09 Milling D80-D99.indd 82 2009-11-24 12:50:00 A General turning Turn milling – how to apply Offset and width of cut For milling a surface that is wider than the cutter diameter, it is necessary to remain in the initial position and then to move the cutter in the axial direction to the required length, which is, however, not more than 80% of the aez1 per revolution. If a 90° shoulder is required, the cutter has to move to second a position, Ew2. Parting and grooving B C Width of cut Threading Wiper width The milling tool should be fed into the workpiece in the radial direction. The workpiece rotation speed should correspond to the feed/tooth recommended for the insert. The cutter should be fed out axially. E Drilling Infeed principle Milling D vf/2 F vf Boring vf/2 Tool holding/ Machines G Programming Detailed information about turn milling programming is provided in the Turn Milling application guide, C-2920:26. Contact your local Sandvik Coromant representative for more information. Materials H D 83 MTG09 Milling D80-D99.indd 83 Information/ Index I 2009-11-24 12:50:01 General turning A Slot and thread milling – application overview Slot and thread milling Application overview Parting and grooving B Side and face milling C Choice of tools D 87 Threading How to apply D 88 Milling D Drilling E F Boring Thread milling Choice of tools D 95 G Tool holding/ Machines How to apply D 97 Materials H Information/ Index I D 84 MTG09 Milling D80-D99.indd 84 2009-11-24 12:50:06 A General turning Slot and thread milling – application overview Parting and grooving B End milling of slots C Choice of tools D 91 Threading How to apply D 92 Milling D Drilling E Boring F Tool holding/ Machines G Materials H Milling Trouble shooting D 128 D 85 MTG09 Milling D80-D99.indd 85 Information/ Index I 2009-11-24 12:50:07 Slot milling – comparsion of cutter concepts Slot milling B Slot milling is an operation in which side and face milling are often preferred to end milling. Parting and grooving General turning A Threading C • Slots or grooves can be short or long, closed or open, straight or non-straight, deep or shallow, wide or narrow. • Tool selection is normally determined by the width and depth of the slot and, to some extent, length. • Available machine type and frequency of operation determine, whether an end mill, long edge cutter or side and face milling cutter should be used. • Side and face cutters offer the most efficient method for milling large volumes of long, deep slots, particularly when horizontal milling machines are used. The growth of vertical milling machines and machining centres, however, means that end mills and long edge cutters are also frequently used in a variety of slot milling operations. Milling D E Comparison of cutter concepts End milling + Open slots + Deep slots + Adjustable width/tolerances + Gang milling + Cutting off + Large product range for different widths/depths + Closed slots + Shallow slots + Non-linear slots + Versatility – additional methods: • Trochoidal slot milling for difficult materials (hard steels, HRSA, etc.) • Plunge milling as a problem solver for long tool overhangs • Additional semi-finishing/finishing operations can be added easily • An endmill can be used for operations other than slot milling Drilling Side and face milling Boring F Tool holding/ Machines G – Closed slots – Linear grooving only – Chip evacuation – Deep slots – High forces – Vibration sensitive if deflected Materials H Information/ Index I D 86 MTG09 Milling D80-D99.indd 86 2009-11-24 12:50:16 A Side and face milling cutters can handle long, deep, open slots in a more efficient manner, and provide the best stability and productivity for this type of milling. They can also be built into a “gang” to machine more than one surface in the same plane at the same time. B Parting and grooving Side and face milling General turning Side and face milling – choice of tools Threading C Choice of tools D CoroMill® 331 CoroMill® 329 T-Max Q-cutter CoroMill® 327 CoroMill® 328 Milling Side milling cutters 10/26.5 2.5 – 4 6.1 5.15 5.15 Max. cutting depth (ar), mm 34.0/114.5 18 119 6.5 5.0 Cutter dia. (Dc), mm 40 – 125/ 80 – 315 125 – 160 80 – 315 9.7 – 27.7 39 – 80 Material P M K N S H P M K N S H P M K N S H P M K N S H P M K N S H F Boring Max. cutting width (ap), mm Drilling E CoroMill® 331 Multi-purpose cutter with high precision capability. The most productive cutter for producing slots and for cutting off. Wide slots can be produced by several CoroMill cutters mounted together in a gang. CoroMill® 329 Versatile tool for producing accurate slots, plain bottom grooves and for cutting off. CoroMill® 327 Internal grooving and chamfering in holes over 10 mm in diameter. Full radius for standard seal rings, and circlip grooves and chamfering. CoroMill® 328 General grooving, circlip grooving and chamfering in holes over 39 mm in diameter. General grooving externally and internally. H Materials T-Max® Q-cutter Complementary cutter for narrow slots and plain bottom grooves. Basic choice for cutting off. Tool holding/ Machines G D 87 MTG09 Milling D80-D99.indd 87 Information/ Index I 2009-11-24 12:50:20 General turning A Parting and grooving B Threading C Milling D Drilling E Boring F Tool holding/ Machines G How to apply Application checklist and hints • Choose cutter size, pitch and position so that at least one edge is in the cut at all times. • Check chip thickness to achieve the optimum feed per tooth. • Reduce feed on entry due to thick chip exit. • In demanding milling, check the requirements for power and torque. • Stiff arbors and overhang are very important in applications in which arbors have a free end. Fixture and arbor support must be strong to handle up-milling cutting forces. Down-milling • First choice method. • Use a firm stop in the direction of tangential cutting forces to prevent them from forcing the workpiece down against the table. The feed direction corresponds with the cutting forces, which means that rigidity and eliminating backlash are also important, since the cutter has a tendency to climb. Up-milling: • Alternative in applications where problems arise due to insufficient rigidity, or when working on exotic materials. • Solves problems generated by weak set-ups and chip jamming in deeper grooves. Fly-wheel: • Good complement for weak set-ups and when available power and torque are low. • Position the flywheel as close to the tool as possible. • Strengthening the workpiece mounting is always a good investment. Milling open slots using side and face milling cutters Calculating feed per tooth A critical factor in peripheral milling using side and face milling cutters, like CoroMill 331, is achieving a suitable feed per tooth, fz. Insufficient values cause serious disadvantages, so that extra care should always be taken when calculating this. The feed per tooth, fz, should be decreased for deeper slots and increased for shallower ones in order to maintain the recommended maximum chip thickness. For information about how to optimize feed, see Getting started, Maximum chip thickness, peripheral milling, page D 20. Materials H Side and face milling – how to apply Information/ Index I ➤ D 88 MTG09 Milling D80-D99.indd 88 2009-11-24 12:50:20 Side and face milling – how to apply A ae/Dc (%) fz (mm/tooth) General turning 25 0.12 10 0.17 5 0.23 ➤ Note: Because two inserts work together to cut the full slot width, feed is calculated using half the number of inserts zn. B Parting and grooving Example: When full slotting with a CoroMill 331 with an insert size 05 and geometry PL, maximum chip thickness should be 0.10 mm which equals: Depth of cut In general, a CoroMill 331 will machine slots to a depth ae of 4 x width ap. For deeper slots, a special cutter can be ordered, see page D 186. If deeper slots are to be machined, feed per tooth should be decreased. If the slot is shallower, increase feed. C Threading Note: The depth of a slot can be limited by the diameter of the arbor boss, the deformation strength of the driving keys, and the capacity of the chip pockets. D Fly-wheel – on horizontal machines Milling Only a few teeth are engaged at any one time in side and face milling operations, which can generate heavy torsional vibrations due to the intermittent machining. This is detrimental to the machining result and to productivity. • Employing a fly-wheel is often a good solution for reducing these vibrations. • Problems caused by insufficient power, torque and stability in the machine are often solved by the correct use of fly-wheels. • The need for a fly-wheel is greater in a small machine with low power, or in a machine with greater wear, than in a larger, more stable and powerful machine. • Position the fly-wheel as close to the tool as possible. • Using a fly-wheel results in smoother machining, which in turn leads to a reduction in noise and vibration, and a longer tool life. • In addition to up-milling, a fly-wheel can be fitted to the arbor on which the milling cutter is set up. • In order to further improve stability when side and face milling, use the largest possible fly-wheel that the application permits. • Combining a number of round carbon steel discs, each with a centre hole and key groove to fit the arbor, remains the best method for constructing a fly-wheel. • The effect of the weight of a fly-wheel increases as the diameter of the fly-wheel increases. This means that if circumstances permit a large diameter, the weight of the fly-wheel can be reduced. • Fly-wheel weight can, if necessary, be distributed over several fly-wheels where space permits. • Higher spindle speeds and a larger cut reduce the need for a fly-wheel. • Use the smallest possible milling cutter diameter – spindle speed can be increased for a particular cutting speed. Drilling E Boring F Tool holding/ Machines G Materials H D 89 MTG09 Milling D80-D99.indd 89 Information/ Index I 2009-11-24 12:50:20 General turning A Parting and grooving B Side and face milling – how to apply Gang milling using cutters mounted in a staggered pattern CoroMill 331 cutters, CoroMill 329, T-Max Q-cutter and CoroMill 328 versions that have bore mounting with keyways can be arranged in a staggered pattern for milling more than one slot at the same time. Displacing the cutters half a pitch in relation to each other assists in avoiding vibration. This also reduces the need for fly-wheels. Threading C D One of the keyways is displaced from the centre-line by half a pitch. Milling Milling of narrow and shallow slots and grooves The CoroMill 327/328 cutters have multiple edge inserts that are available in shapes to fit most types of small grooves. E Drilling Common applications include the machining of internal circlip and sealring grooves, and of small straight or circular external grooves, particularly on components that cannot be rotated. Boring F Internal grooving • A smooth entrance should be programmed when using circular milling. • Consider the relationship between the cutter diameter and the hole diameter, Dc/ Dw. The smaller the relationship, the larger the engagement will be. G Tool holding/ Machines Cutting speed and chip thickness recommendations for CoroMill® 327 vc, m/min: P 200 (150-400) M 100 (80-160) H K 250 (200-400) hex, mm: Materials 0.04 (0.01 – 0.07) Suitable cutting data for CoroMill 328 are recommended on page D197. Information/ Index I D 90 MTG09 Milling D80-D99.indd 90 2009-11-24 12:50:25 A End milling is selected for shorter, shallower slots, especially closed grooves and pockets, and for milling key-ways. B Parting and grooving End milling of slots General turning End milling of slots – choice of tools End mills are the only tools that can mill closed slots that are: • Straight, curved or angled • Wider than tool diameter, designated pockets. Heavier slotting operations are often performed using long edge milling cutters. Threading C Choice of tools D CoroMill® 690 CoroMill® 390 CoroMill® 490 CoroMill® 316 CoroMill® Plura Milling End milling and long edge cutters 15.7/85 5.5 11 38 50 – 84 12 – 42/32 – 200 20 – 80 10 – 25 2 – 20 Ramping* No Yes No Yes Yes Material S P M K N S H P M K S H P M K N S P M K N S H Cutter dia. (Dc), mm F Boring 112 Max. cutting depth (ap), mm Drilling E *Ramping is a suitable method for closed slots, see Dedicated methods, page D 104. Tool holding/ Machines G Materials H D 91 MTG09 Milling D80-D99.indd 91 Information/ Index I 2009-12-06 09:40:34 General turning A Parting and grooving B End milling of slots – how to apply How to apply Application checklist and hints • Use light-cutting end mills with a long predictable tool life mounted in high-performance chucks. • Minimize the distance from the tool chuck to the cutting edge to achieve the shortest possible overhang. C Threading • For long tool overhangs, make shallow cuts with heavier feeds. • Consider feed per edge to produce satisfactory chip thickness. Use coarse pitch cutters to avoid thin chips, which can cause vibrations, bad surfaces and burr formation. D Milling • Use the largest possible tool size to achieve the best diameter/length relationship for stability. • Use down-milling as often as possible to achieve the most favorable cutting action. E Drilling • Make sure to evacuate chips out of the groove. Use compressed air to avoid chip congestion. • Use Coromant Capto coupling for best stability and support towards the spindle. F Boring For information about how to enhance the milled groove or pocket to the required shape and quality, see Dedicated methods, page D 120. Tool holding/ Machines G Materials H Grooving using end milling cutters Machining a groove or slot, often called full slotting, involves three machined faces: • Slots closed at both ends are pockets, requiring end mills that can work in the axial direction. For more information about pocketing, see page D 115. • Full slotting with an end mill is a demanding operation. The axial cutting depth should be generally reduced to around 70% of the edge length. Machine rigidity and chip evacuation should also be considered in determining the best method for the operation. • End mills are sensitive to the effects of cutting forces. Deflection and vibration may be limiting factors, especially at high machining rates and with long overhangs. Information/ Index I D 92 MTG09 Milling D80-D99.indd 92 2009-11-24 12:50:31 A General turning End milling of slots – how to apply Keyway slotting This operation requires some specific guidance, in addition to the general recommendations for milling of straight surfaces and grooving. B Parting and grooving A slot milled in a single step will not have a perfectly square form due to the direction of the cutting forces and the tendency of the tool to bend. The best accuracy and productivity will be achieved if the operation employs an undersized end mill, and is divided into two steps: C 1. Key slot milling – roughing of full slot. 2. Side milling – finishing all around the slot, using up-milling to create true square corners. Threading The radial depth of cut should be kept low in finishing operations to avoid deflection of the cutter, which is a major cause of bad surface finish and/or deviation from a true 90° shoulder. D Milling Key slot milling in two steps. E Methods for opening up a closed slot or pocket in a solid blank Drilling In preparation for milling long and narrow, full-width slots, linear ramping is the most common method, after drilling, for opening up a pocket. For shallow slots, peck milling can also be an alternative. Circular ramping is used for milling wider slots and pockets. For more information, see Dedicated methods, page D 102. Boring F Tool holding/ Machines G Materials H D 93 MTG09 Milling D80-D99.indd 93 Information/ Index I 2009-11-24 12:50:34 General turning A End milling of slots – how to apply Comparison of three different methods Conventional slot milling Trochoidal milling Plunge milling + Conventional 3-axes machines can be used + High removal rates under stable conditions + Simple programming + Wide choice of tools – Generates high radial cutting forces – Vibration sensitive – deep slots require repeated passes + Generates low radial cutting forces - less vibration sensitivity + Minimal deflection when milling deep slots + A productive method for: • machining hard steels and HRSA (ISO H and S) • vibration sensitive applications + The slot width should be maximum 70% of the cutter diameter, Dc + Good chip evacuation + Low heat generation – More programming is required + A problem solver in vibration sensitive applications: • with long tool overhangs • in deep slotting • with weak machines or set-ups – Low productivity under stable conditions – Requires a rest milling/finishing operation – End cutting might obstruct chip evacuation – Limited choice of tools For more information, see Dedicated methods, page D 121. For more information, see Dedicated methods, page D 116. Parting and grooving B Threading C Milling D Drilling E Boring F Rough slotting with long edge milling cutters • Cutters with large metal removal capacity are generally used for rough machining. • Shorter versions may produce slots up to a depth equal to the diameter, in stable and powerful milling machines. • Use stable ISO 50 spindles, as these cutters are more likely to accommodate considerable radial forces. • Check power and torque requirements, as these are often limiting factors for optimum results. • Consider the optimal pitch for each type of operation. Materials Information/ Index H M Application area: Long set-up Universal Short set-up Shoulder milling: Deep ap /ae Medium ap /ae Moderate ap /ae Slot milling: Moderate ap Limited – ➡ vc m/min: I L ➡ H Pitch ➡ Tool holding/ Machines G Longer designs are primarily intended for edging operations, see Shoulder milling, page D 50. D 94 A Thread milling in non-rotating components is a good alternative to tapping, and can also be an alternative to thread turning. B Parting and grooving Thread milling General turning Thread milling – choice of tools With CoroMill thread milling cutters, it is possible to create threads very near to a shoulder or bottom of a hole. The interrupted cut in milling provides good chip control in long-chipping materials. Threading C Choice of tools D CoroMill® 327 CoroMill® 328 Pitch, mm 0.7 – 3 1 – 4.5 1.5 – 6 Cutter dia. (Dc), mm 3.2 – 19 11.7 – 21.7 39 – 80 Material P M K N S H P M K N S H P M K N S H E Drilling CoroMill® Plura Milling CoroMill Plura end mill cutters as well as CoroMill 327 and CoroMill 328 offer geometries optimized for thread milling. Boring F General information G Tool holding/ Machines • Select the shortest tool whenever possible. • The ordering information provides the smallest internal thread size that each tool can produce. The same thread mill can also be used for any larger size threads of the same pitch. See Main catalogue for more information. Materials H For information about thread standards and thread turning vs thread milling, see Threading, Chapter C. For pre-drilling recommendations, see Information/Index, Chapter I, Thread charts. D 95 MTG09 Milling D80-D99.indd 95 Information/ Index I 2009-11-24 12:50:44 General turning A Parting and grooving B C Thread milling – choice of tools Use of CoroMill® cutters for threading Advantages • Same tool for right and left-hand threads. • Same tool for a wide range of thread diameters with no upper limit for bore size. • Full thread close to the bottom of blind holes as well. • Can be adjusted to specified tolerances. • Preferred solutions for long reach requirements and to avoid vibration. • Good chip control. • Good chip evacuation provides secure performance. • Provide favorable results in hardened materials, and when machinability and chip formation are bad. • Internal cutting fluid supply facilitates threading in difficult to machine materials. • In the event of tool breakage , it is easy to remove the cutter without damage to the workpiece. Threading Disadvantages Milling D • Thread milling cutters will always produce feed marks. Depending on pitch size, hole size and radial immersion, the thread will deviate from the perfect profile. • Relatively high cutting forces with the CoroMill Plura can cause tool deflection and slightly distorted/tapered threads. • Pitch is individual for each CoroMill Plura. Drilling E Boring F Singlepoint threading with CoroMill® 327 and CoroMill® 328 • Same insert for different pitches. • Low cutting forces make these cutters a good alternate choice for internal medium to large threads, and for when stability is bad – such as for milling threads requiring long tool overhangs and/or in thin walled components. • Low power requirements. • First choice for creating larger, external threads on asymmetric components. • For small batch sizes and mixed production. Tool holding/ Machines G H Multipoint threading with CoroMill® Plura Materials • Completes a thread in only one single 360° pass. • For selection of tools, cutting data and for programming, see the CoroMill Plura Guide. Information/ Index I D 96 MTG09 Milling D80-D99.indd 96 2009-11-24 12:50:47 Thread milling – how to apply General turning How to apply A General • Always engage and retract the CoroMill Plura, the CoroMill 327 and the CoroMill 328 following a smooth tool path. Parting and grooving B • Down-milling is preferable. • When milling threads in hardened steel or in other difficult to cut materials, it may be necessary to separate the operation into several passes by reducing ae or fz. C Threading Right-hand threads All cutters are initially positioned as close as possible to the bottom of the hole and then moved counter-clockwise upwards. D Pitch Milling Left-hand threads Milling a left-hand thread follows in the opposite direction, from top to bottom, yet, also in a counter-clockwise path. E Down-milling is recommended. Drilling Pitch F Boring Thread profile deviation • Thread milling cutters will create a negligible, small form error thread profile. • This depends on the relationship between the threading diameter and cutting diameter, and also on the pitch. • A good rule is that the relationship between the threading diameter and the cutting diameter should be no less than 1.5. Tool holding/ Machines G Materials H D 97 MTG09 Milling D80-D99.indd 97 Information/ Index I 2009-11-24 12:50:48 General turning A External threading – CoroMill® 327 and CoroMill® 328 All threading inserts are primarily used for internal threading. However, all partial profile inserts (v-profile) can be used for external threading as well. Note: Be aware of the depth of the thread. Example: CoroMill 327 with ordering code 327R12-22 100VM-TH. C Conclusion: • For internal threading, pitch 2 is enough, since ar is 1.2 mm (ar maximum 1.2 mm). • For external threading, pitch 2 is not enough, since ar is 1.4 mm (ar maximum 1.2 mm). • Use pitch 2.5 to 3.5 to produce the threads. Threading Parting and grooving B Thread milling – how to apply Recommendation: • Pitch 1 to 2 mm (minimum 1, maximum 2) • ar maximum 1.2 mm Milling D Drilling E • Thread milling requires a machine tool capable of simultaneous movements in the X, Y and Z axes. • The X and Y axes determine the diameter of the thread, while the Z axis will control the pitch. • Thread milling is preferably performed dry. • Different micro-lubrication systems, which use compressed air along with small amounts of special types of oil, can be favorably employed to assist in chip evacuation. Boring F Machine tool requirements G Programming Tool holding/ Machines General • Programming with radius correction allows for easy adjustment of thread tolerances. • In case a thread tolerance is produced too tightly, compensation can be applied by a small adjustment (reduction) of the radius correction value. Materials H The cutting diameter of each tool has to be considered carefully when the operation is programmed. Information/ Index I D 98 MTG09 Milling D80-D99.indd 98 2010-01-04 14:13:54 A General turning Thread milling – how to apply CoroMill® Plura CoroMill Plura has an individual radius programming (RPRG) value marked on the shank of the tool. • The RPRG value indicates each cutter's exact pitch diameter and the radius correction required for optimum thread quality. • The RPRG value is normally entered into the tool memory offset. • Using the RPRG will prevent the first thread from being too large, as long as the operational conditions are good. Parting and grooving B C Threading Tool radius programming value. D Cutting data recommendations Milling • In internal applications, the periphery of the tool will rotate faster than centre-line of the tool. • Programming of the feed rate (mm/min) on most milling machines is based on the centre-line of the spindle. This fact must be included in the calculations for the thread milling in order to avoid shortened tool life, vibration, or complete breakdown. • CoroMill Plura thread milling cutters have a larger surface area contact than end mills of equal lengths, and often a less favorable length to diameter ratio. • The same cutting speed that is used for conventional end mills can be used for thread milling cutters. • For shallow cuts, the feed rate should not exceed 0.15 to produce a good thread surface. Drilling E F vfm × (Dm – Dcap) Dm Boring vf = Tool holding/ Machines G Materials H D 99 MTG09 Milling D80-D99.indd 99 Information/ Index I 2009-11-24 12:50:49 General turning A Dedicated methods – application overview Dedicated methods Application overview Parting and grooving B C Peck milling Choice of tools D 119 Linear ramping How to apply D 119 Choice of tools D 102 Threading How to apply D 108 Milling D Drilling E F Circular ramping Circular milling Boring Choice of tools D 102 How to apply D 110 Tool holding/ Machines G H Chamfering Materials Choice of tools D 126 How to apply D 127 Information/ Index I D 100 MTG09 Milling D100-D115.indd 100 2009-11-26 10:17:02 A General turning Dedicated methods – application overview Closed pockets Choice of tools D 125 Parting and grooving B How to apply D 125 C Threading Plunge milling Choice of tools D 116 Cavity milling D How to apply D 117 Milling How to apply D 115 Drilling E Boring F G Tool holding/ Machines Slicing methods Choice of tools D 120 How to apply D 121 Materials H Milling Trouble shooting D 128 D 101 MTG09 Milling D100-D115.indd 101 Information/ Index I 2009-11-24 12:56:15 General turning A Overview - holes and cavities Creating openings in a solid workpiece Parting and grooving B Dedicated methods – overview C Threading Linear ramping Opening a slot Linear ramping (2-axis simultaneously) is always to be preferred in comparison to peck milling. Peck milling is an alternative method, but it often produces long chips and generates undesirable cutting forces on the cutter. Milling D Peck milling Drilling E F Boring Namnlöst-1 1 Tool holding/ Machines G Drilling Circular ramping Ramping a cavity Opening a hole or a cavity Drilling is the traditional and fastest method for producing a hole, but chip breaking can be a challenge in some materials, and it lacks the flexibility to produce varying diameters and non-round shapes. Circular ramping (3-axis simultaneously) is a less productive method compared with drilling, but can be a good alternative in case of: • Large diameter holes when machine power is limited. • Smaller series production. A rule of thumb for diameters larger than 25 mm: milling is cost efficient up to a series of approx. 500 holes. • When a range of hole sizes are to be machined. • Limited tool magazine space to store many drill sizes. • Production of blind holes, when a flat bottom is required • Non-rigid, thin walled components. • Interrupted cuts. • Materials difficult to drill, due to chip breaking and chip evacuation. • No cutting fluid is available. • Cavities/pockets (“non-round holes”). 2009-08-31 09:29:34 H Materials Namnlöst-1 1 Information/ Index I D 102 MTG09 Milling D100-D115.indd 102 Namnlöst-1 1 2009-08-31 09:29:34 2009-11-24 12:56:21 A General turning Dedicated methods – overview Widening a hole or a cavity Parting and grooving B Boring Circular ramping Circular milling C Boring is normally the fastest method, for the same reasons as drilling, but milling is sometimes a good alternative, see previous page. Two alternate milling methods can be used: Circular ramping (3-axis) or circular milling (2-axes). Circular ramping is to be prefered when the hole is deeper than ap max, or in vibration sensitive applications. Also the roundness/concentricity of the hole becomes better when ramping, especially at long overhangs. Roundness will be improved if the workpiece is rotated instead of moving the milling cutter in a circular path in both circular ramping and milling operations. Threading Widening a hole D Widening a cavity E Internal shoulder milling Namnlöst-1 1 Plunge milling Drilling • Ramping (3-axes) has an advantage because it only requires one tool and can produce 3D-shapes, making is suitable in profile milling. If applied with high feed techniques (light and fast), the cutting forces will be directed in a favorable manner that minimizes vibration problems. • Plunge milling often solves problems with long overhangs and/or deep cavities. • Internal shoulder milling requires more programming than plunge milling, but is faster. Milling Internal shoulder milling and plunge milling require a starting hole and should be compared to ramping a cavity directly into a solid block, see previous page. 2009-08-31 09:29:34 Boring F Tool holding/ Machines G Plunging in corners Slicing technique – light and fast Slicing in corners Trochoidal H When the roughing of a cavity is completed, stock often remains, especially in corners. Plunge milling with a smaller cutter is one method for coming closer to the finished shape. Slicing (light and fast) is another technique often used in corner milling. Trochoidal milling is one type of slicing technique that is also used for milling slots, pockets etc. Namnlöst-1 1 Materials Rest (remaning stock) milling 2009-08-31 09:29:34 D 103 MTG09 Milling D100-D115.indd 103 Information/ Index I 2009-11-24 12:56:32 Linear ramping (2-axes) / circular milling (2-axes) / circular ramping (3-axes) Linear ramping (2-axes) B Linear ramping is commonly used as an efficient way to approach the workpiece when machining closed slots/pockets/ cavities, and it eliminates the need for a drill. Parting and grooving General turning A C Linear ramping is defined as simultaneous feeding in the axial direction (Z) and in one radial direction (X or Y), i.e. two-axes ramping. Circular ramping is always prefered to straight ramping (full slotting), because the radial cut is reduced and allows for pure down-milling and better chip evacuation. Threading A counter-clockwise rotation ensures down-milling. Linear ramping for opening a closed slot. Milling D Drilling E Circular milling is an alternate method to the traditional use of boring tools. Circular milling can be performed by moving most 90 degree cutters in a circular tool path. Boring F Circular milling (2-axes) Tool holding/ Machines G Materials H Information/ Index I D 104 MTG09 Milling D100-D115.indd 104 2009-11-24 12:56:34 A Feeding the cutter in a circular ramping path, moving simultaneously in the X , Y and Z directions, is often used for opening up a cavity/pocket. It is also an alternate hole making method to drilling and boring, see comparison on page D 102. B Parting and grooving Circular ramping (3-axes) General turning Linear ramping (2-axes) / circular milling (2-axes) / circular ramping (3-axes) C Circular ramping in a solid workpiece. Threading P = pitch (mm/rev) Milling D E Drilling Circular ramping to widen a hole. Circular ramping - first choice cutters Hole diameter (mm) Flat bottom M Through hole Flat bottom K Through hole Flat bottom N Through hole Flat bottom S Through hole 28 CoroMill® Plura/CoroMill® 316 CoroMill® Plura/ CoroMill® 316 30 32 34 36 38 40 CoroMill® 390 CoroMill® 390 48 50 52 54 56 58 60 CoroMill® 210 G CoroMill® 300 CoroMill® 300 CoroMill® Plura/CoroMill® 316 CoroMill® 390 CoroMill® 210 CoroMill® 390 CoroMill® Plura/CoroMill® 316 CoroMill® 210 CoroMill® 390 CoroMill® 390 CoroMill® Plura/CoroMill® 316 CoroMill® Plura/ CoroMill® 316 46 CoroMill® 390 CoroMill® Plura/CoroMill® 316 CoroMill® Plura/ CoroMill® 316 44 CoroMill® 210 CoroMill® Plura/ CoroMill® 316 CoroMill® Plura/ CoroMill® 316 42 Boring 26 CoroMill® 390 Tool holding/ Machines P Through hole 24 H CoroMill® 790 CoroMill® 790 CoroMill® 390 Materials Flat bottom 22 CoroMill® 300 CoroMill® 210 I D 105 MTG09 Milling D100-D115.indd 105 Information/ Index 20 F 2009-11-24 12:56:36 General turning A Choice of tools Cutters that can perform linear ramping can also perform circular ramping. Note: When machining a blind hole, the minimum Dm will be larger if a flat bottom profile is required. It can be calculated using the formula specified on page D 111. Parting and grooving B Dedicated methods – choice of tools Linear ramping Threading C Linear Circular Linear ap < 0.55 x Dc Hole quality H7 H7 Max. ap = 0.9 x Dc Through hole ap = 0.55 x Dc Dm min P mm/r a° lm Through hole Dc alt. D3 (mm) Milling Dm min P mm/r a° lm 4 4.8 0.26 6.7 30.6 6 7.2 0.43 6.7 46.0 8 9.6 0.53 6.7 61.3 10 12 0.66 6.7 76.6 12 0.78 10 31.2 12 14.4 1.39 10 61.2 14.4 0.89 10 37.4 16 19.2 1.77 10 81.7 19.2 1.1 10 49.9 20 24 2.21 10 102.1 24 1.37 10 62.4 30 1.65 10 78.0 25 Circular ramping hole depth P = pitch CoroMill® 390 Drilling Boring Tool holding/ Machines Materials Information/ Index Corner radius end mill < ap CoroMill® 790 Insert size 11 and 18* re=0.8 mm Insert size 17 with re=0.8 mm Insert size 16 with re=0.8 mm Insert size 22 with re=0.8 mm F I VFD, Helix 50° Max. hole depth E H CoroMill® 316 Circular D G CoroMill® Plura Circular Linear Circular Linear < l3** Linear Circular Max. hole depth < l3** Hole quality H9 Max. H9 Max. H7 Max. H7 Max Through hole ap = 10 / 15* mm Through hole ap = 15 mm Through hole ap = 12 mm Through hole ap = 18 mm a° lm Dm min P mm/r a° lm Dm min P mm/r a° lm Dm min P mm/r a° lm 99 45.7 74 Dc alt. D3 (mm) < l3** Linear Circular < l3** Dm min P mm/r 12 14 0.4 6.0 16 20 2.0 10.5 54 20 24 2.0 5.5 104 25 39 3.0 5.0 114 33 6.0 15.5 59 28.8 4.3 19 32 53 3.3 3.6 159 47 4.5 6.7 135 42.8 8.1 13 66 36 61 2.7 2.6 220 50.8 9.3 11 78 40 78* 7.0* 6.8* 132* 58.8 10.2 9 89 51 11.5 18 44 86* 6.5* 6.0* 149* 60.8 10.8 8 101 59 13.7 16 84 50 98* 6.0* 5.5* 163* 78.8 11.6 7 118 71 15.7 13 100 54 106* 4.5* 5.0* 179* 86.8 11.9 6 130 79 11.7 12 111 63 124* 4.0* 4.0* 225* 97 18 9 134 66 130* 3.5* 3.7* 243* 103 18 9 141 80 158* 3.0* 3.1* 290* 131 18 7 176 63 4.0 3.9 231 83 1.0 2.8 323 109 1.6 2.1 430 143 1.6 1.6 565 * Insert size 18 has dedicated ramping geometries -xMR ** Note: If oversized cutters then depth can be up to 3xD. D 106 MTG09 Milling D100-D115.indd 106 2009-11-24 12:56:36 A General turning Dedicated methods – choice of tools Insert size 09 Circular Insert size 14 Linear B CoroMill® 300 Circular Insert size 08 Linear Circular Parting and grooving CoroMill® 210 Insert size 10 Linear Circular Linear Max. hole depth < l3** Hole quality H13 Max. H13 Max. H13 Max. H13 Max. Through hole ap = 1.2 mm Through hole ap = 2.0 mm Through hole ap = 4 mm Through hole ap = 5 mm P mm/r a° Dm min a° Dm min P mm/r a° lm Dm min Dc alt. D3 (mm) lm < l3** P mm/r lm < l3** P mm/r a° lm C 32 1.2 14.5 4.6 36.4 2 8.0 28.5 32.4 2.5 13.5 20.8 32 46 1.2 8 8.5 50.4 2 5.0 45.7 46.4 2.5 7.5 38.0 35 52 1.2 7 9.7 56.4 2 4.0 57.2 36 54 1.2 7 9.7 66.4 2 3.5 65.4 52.4 2.5 6.5 43.9 42 66 1.2 5 13.7 70.4 2 3.0 76.3 62.4 2.5 5.0 57.2 D 50 82 1.2 3.5 19.6 66.4 2.5 4.5 63.5 52 86 1.2 3.3 20.8 63 108 1.2 2.6 66 114 1.2 2.4 40 86.4 2 2.5 91.6 76 2 5.8 19.6 90.4 2 2.0 114.5 26.4 98 2 3.8 30.1 112.4 2 1.5 152.8 28.6 104 2 3.2 35.7 118.4 2 1.5 152.8 132 2 2.4 47.7 146.4 2 1.0 229.2 80 Milling 25 Threading Dm min < l3** E Circular Insert size 16 Linear Circular Insert size 20 Linear F Linear Max. hole depth < l3** Hole quality H13 Max. H13 Max. H13 Max. Through hole ap = 6 mm Through hole ap = 8 mm Through hole ap = 10 mm Dm min P mm/r a° lm Dm min P mm/r a° lm 65.2 60.5 Dc alt. D3 (mm) < l3** Circular < l3** P mm/r a° lm 32 42.6 3 12.0 28.2 34 46.6 3 11.5 29.5 35 48.6 3 10.5 32.4 40 58.6 3 8.0 42.7 42 62.6 3 7.5 45.6 50 78.6 3 5.5 62.3 52 82.6 3 5.0 68.6 75.6 4 7.0 63 104.6 3 3.5 98.1 97.6 4 5.0 91.4 66 110.6 3 3.5 98.1 103.6 4 4.5 101.6 96 5 9.4 80 138.6 3 2.5 137.4 G Tool holding/ Machines Dm min Boring Insert size 12 Drilling CoroMill® 300 4 3.5 130.8 124 5 6.7 85.2 171.6 4 2.5 183.2 164 5 4.8 119.2 125 221.6 4 1.5 305.5 124 5 3.5 163.5 Materials 131.6 100 H ** Note: If oversized cutters then depth can be up to 3xD. D 107 MTG09 Milling D100-D115.indd 107 Information/ Index I 2009-11-24 12:56:37 Dedicated methods – choice of tools General turning A Parting and grooving B CoroMill® 200 Insert size 10 Circular Insert size 12 Linear Circular Insert size 16 Linear Circular Linear Hole quality H13 Max. H13 Max. H13 Max. H13 Max. Through hole ap = 5 mm Through hole ap = 6 mm Through hole ap = 8 mm Through hole ap = 10 mm Dm min P mm/r a° lm Dm min P mm/r a° lm Dm min P mm/r a° lm 32 42 3 13 26 40 58 3 9.5 32 50 4 13 35 50 78 3 6.5 49 70 4 11 35 62 5 13 43 63 104 3 4.5 68 96 4 7 48 88 5 11 45 80 138 3 3.5 98 130 4 5 70 122 5 7 67 100 178 3 2.5 137 170 4 3.5 102 162 5 5 95 220 4 2.5 131 212 5 3.5 127 282 5 2.5 191 25 Threading Dm min P mm/r a° lm 32 2.5 13 22 125 < l3** Circular < l3** C 160 < l3** ** Note: If oversized cutters then depth can be up to 3xD. Milling D Linear Max. hole depth Dc alt. D3 (mm) < l3** Insert size 20 E Drilling How to apply F Two axes ramping – linear A demanding cutting process There are three cutting processes that occur simultaneously during the ramping operation: Boring 1) Periphery cutting with the leading insert. 2) Bottom cutting with the leading insert. 3) Bottom cutting with the trailing insert. There is also added stress on the tool due to full slotting, which means that ae=Dc, creating large radial forces and long chips. Tool holding/ Machines G The cutting forces are both axial and radial. Materials H Information/ Index I D 108 MTG09 Milling D100-D115.indd 108 2009-11-24 12:56:38 A General turning Dedicated methods – how to apply Machining recommendations • Reduce feed to 75% of normal. • When slot milling is performed directly after ramping, it is important to continue at a lower feed, for a distance that corresponds to the cutter diameter, until the trailing insert has stopped cutting. • Use cutting fluid to help with chip evacuation. • Reduce the radius on the tool to reduce the area of contact. • Straight ramping should be limited to narrow slots less than 30 mm wide, if access for helical ramping is limited. Parting and grooving B When ramping in several passes to produce a deep slot, the productivity can be easily increased by ramping in both directions (progressive ramping) instead of ramping in only one (single pass ramping). Note: When feeding the cutter at the maximum ramping angle, it must be lifted the distance h before changing direction. This prevents damage to the central part of the cutter body. Threading C Progressive ramping D Milling Single pass ramping. Tool path correction: E Drilling h = Tang a (Dc - (2 x iW)) F Boring Progressive ramping at maximum ramping angle. Insert radius affects maximum ramping angle Example CoroMill® 790 G The curves in the diagram are valid for minimim and maximum radii. For intermediate radii, please interpolate. Tool holding/ Machines (a) Ramping angle 30° rε = 0.5 mm rε = 6.35 mm 15° rε = 0.5 mm 10° rε = 5.0 mm 5° H = Insert size 22 = Insert size 16 Materials 20° 0° 20 30 40 50 60 70 80 90 100 110 120 130 I Tool diameter, Dc mm D 109 MTG09 Milling D100-D115.indd 109 Information/ Index 25° 2009-11-24 12:56:39 General turning A Parting and grooving B Dedicated methods – how to apply Circular ramping – hole making Circular ramping (also called helical interpolation, spiral interpolation, orbital drilling, etc.) is an alternative to drilling. It is a simultaneous movement in a circular path (X and Y) together with an axial feed (Z) at a defined pitch. Compared to linear ramping (full slotting), helical interpolation is a much smoother process because the radial cut is reduced, it allows for pure down-milling, and provides better chip evacuation. A counter-clockwise rotation ensures down-milling. Threading C Milling D Process considerations There are three key considerations in circular ramping: if not correctly applied, problems will occur. 1. Cutter diameter selection for hole size 2. Pitch per revolution 3. Feed rate E Drilling 1. Cutter diameter selection for hole size Boring F Tool holding/ Machines G H The cutter size selection is very important when using cutters that are not centre cutters. If the cutter is too large, the insert does not inscribe the centre line of the hole, and a pip will be formed which will foul on the bottom of the cutter. Materials Cutter diameter ensures that the insert cuts over the centre line of the hole. Cutter diameter is too small and will leave a core in the middle – like trepanning. This is acceptable for large cut-outs (‘man holes’) but the core needs to be supported as it drops off. I Information/ Index Namnlöst-1 1 2009-08-31 09:29:34 D 110 MTG09 Milling D100-D115.indd 110 2009-11-24 12:56:41 A General turning Dedicated methods – how to apply Maximum diameter hole • The maximum hole diameter, Dm, which can be produced in one continuous spiral, is 2 x D3. • This is full slotting and will leave a pip in the centre of a blind hole. • The pip is removed by feeding to centre for a flat bottom. Parting and grooving B Threading C Max. hole diameter Dm D Milling Max. Dm = D3 x 2 Dm Min. D3 = 2 E Minimum diameter flat bottom Drilling • To ensure that no pip is left on the bottom of a blind hole, the insert radius size needs to be considered. • If the cutter is too big, the pip cannot be removed by feeding to centre. • For CoroMill 390, the wiper length, bs, also needs to be added to the radius size. Boring F Tool holding/ Machines G H Dm 2 + (re + bs) Min. Dm = (D3 – (re + bs )) x 2 Max. D3 = Dm 2 Materials Max. D3 = CoroMill® 300 – min. hole diameter Dm + 0.5 iC Min. Dm = (D3 – 0.5 iC) x 2 I D 111 MTG09 Milling D100-D115.indd 111 Information/ Index CoroMill® 390 – min. hole diameter Dm 2009-12-06 09:44:16 General turning A Parting and grooving B Dedicated methods – how to apply Minimum diameter through hole • The minimum diameter that avoids collision of the cutter body due to non-centre cutting. • b is the maximum stepover allowed for plunging, and is the same for the maximum overlap. • For round inserts, b should be calculated as b = 0.8 x iC. • Pip cannot be removed. Threading C D Milling b E CoroMill® 390 – min. hole diameter Dm CoroMill® 300 – min. hole diameter Dm Max. D3 = Max. D3 = Dm 2 +b Min. Dm = (D3 – b) x 2 Dm 2 + 0.8 iC Min. Dm = (D3 – 0.8 iC) x 2 Drilling 2. Pitch (P) The pitch can never be larger then the maximum ap for the cutter concept, and depends on the hole diameter, the cutter diameter and the ramp angle. Boring F The feed value always depends on the hex-value which corresponds with the peripheral feed rate, vfm. However, many machines require a tool centre feed, vf, which has to be calculated accordingly: Tool holding/ Machines G 3. Feed rate H fz = hex vf = Dvf Dm × vfm Materials Dvf = programmed cutter path Programmed feed rate: vfm = when using radius compensation vf = when using the tool centre feed I Information/ Index vfm = n × fz × zc D 112 MTG09 Milling D100-D115.indd 112 2009-12-06 09:44:34 A General turning Dedicated methods – how to apply Widening an existing hole Widening an existing hole can be performed either by circular ramping or circular milling. Circular ramping – 3 axes B Parting and grooving • Constant ramping. • No entry or exits. • Cutter constantly engaged. • Ramping action – bottom cutting. First choice: • Depth of hole is greater than the maximum ap for tool. • Best hole concentricity and roundness. • In vibration sensitive applications. C Threading Dvf = Dm – Dc D Circular milling – 2 axes E Dvf1 = Drilling Dvf = Dm – Dc Dvf 2 F Namnlöst-1 1 Boring First choice: • Program tool path more than 360 degrees to avoid step marks. • Only one pass is required. – Cutter with high ap capability (CoroMill Plura, CoroMill 390 long edge cutter). – Shallow hole. • Ramping capability poor or nonexistent – long edge without axial support. Milling • Constant Z. • Entering and exiting for each level. • Rolling entrance into cut should be programmed. • Hole tolerance is not as good as helical. • Step marks at each pass. Tool holding/ Machines G Entrance into cut – rolling into cut ensures thin chips on exit. Low engagement angle – reduces vibrations and ensures high productivity. Materials H D 113 MTG09 Milling D100-D115.indd 113 Information/ Index I 2009-11-24 12:56:47 General turning A Parting and grooving B Dedicated methods – how to apply Calculating feed Feed needs to be reduced due to: • Increased ae relative to straight cutting, which reduces the chip thinning effect. • Peripheral feed is greater than the tool centre feed. • Calculate feed based upon Dvf. fz = hex vf = vfm = n × fz × zc sin ß Dvf Dm × vfm Threading C D Circular external milling/ramping Milling Compared to internal circular milling/ramping: E • The tool centre feed, vf, is increased instead of reduced. • The radial depth, ae, becomes much smaller when milling externally, therefore, a higher cutting speed can be used. • hex is calculated in the same way as for edging. • The programming technique is otherwise very similar to internal milling of holes. Drilling For complete information, calculations and formulas, see Information/Index, Chapter I. F Boring External circular ramping (3-axes). vf = vfm × (Dm + Dcap) Dm ae eff = Dw - Dm 2 Tool holding/ Machines G H Materials External circular milling (2-axes). Information/ Index I D 114 MTG09 Milling D100-D115.indd 114 2009-11-24 12:56:50 A General turning Dedicated methods – how to apply Opening up/widening a cavity or pocket There are two clear strategies: 1. Circular ramping (3-axes) – small ap Use a cutter with a small entering angle, CoroMill 210 or corresponding CoroMill 316 or CoroMill Plura high feed cutters. A round insert cutter is another alternative. For more information, see High feed milling, page D 60. Parting and grooving B This “light and fast” technique provides an excellent metal removal rate and is the first choice for less stable machines (acc. to ISO 40) and when the cavity has a profiled shape, i.e. die and mould. Note: Avoid machining all the way against a 90° shoulder because the effect of a low approach angle will be lost, i.e. the depth of cut increases dramatically. C Cutting parameters: Threading • Maximum cutter diameter = 1.5 x component corner radius • Circular ramp to depth – counter-clockwise • Roll into the next cut • Radial cut – max. ae = 70% Dc • Axial cut for round insert cutter 25% iC • Tool path radius in the corner = Dc • Reduce corner feed, see page D 26. Milling D Ramping counter-clockwise tool path. E Drilling 2. Circular milling (2-axes) – large ap Drill a hole, and then change to a shoulder end mill or a long edge cutter. A typical application area is found in aerospace framing – titanium machining. Application hints Ensure good chip evacuation to prevent re-cutting of chips/chip jamming: • Horizontal spindle (ISO 50) is prefered. • High pressure coolant or compressed air with through tool coolant. • Dc should be no greater than 75% of hole dia. Use a large axial cut – maximum ap = 2 x Dc. F Boring The drilled hole should be entered in a circular path: • Control radial engagement, maximum ae = 30% of Dc. Control radial engagement to minimize vibration in corners, and to maximize productivity: • Use the largest radius possible in the corners, spiral morph programming. • Use the largest Dc possible and complete rest milling separately at no greater than 1.5 x the corner radius. Tool holding/ Machines G Spiral morph programming. I D 115 MTG09 Milling D100-D115.indd 115 Information/ Index Small corner radius. Materials H 2009-11-24 12:56:54 Plunge milling – choice of tools Plunge milling B In plunge milling, the cutting is performed at the end of the tool instead of at the periphery, which is advantageous due to the change in the direction of the cutting forces from predominately radial to axial. In general, plunge milling is an alternate method when side millling is not possible due to vibrations. For example: Parting and grooving General turning A C • When the tool overhang is greater than 4 x Dc • When the stability is bad • For semi-finishing of corners • For difficult to cut materials like titanium. Threading It can also be an alternative when machine power or torque is a limitation. Note: Under favorable conditions plunge milling is not the first choice due to a lower metal removal rate. Milling D E Choice of tools Plunge drilling Plunging with drilling tools can be more effective up to approx. Dc = 35 mm, see Drilling, Chapter E. Drilling Cutter selection is determined primarily by the diameter. CoroMill 210 and Coromant plunge cutter R215 are dedicated for plunging. F Application Feed per tooth Insert size (mm) (mm) fz Cutter dia. Max. step over b range (mm) Dc 0.1 8 25 – 66 14 0.15 13 52 – 160 Heavy duty – large diameter with long overhang 25 0.15 22 80 – 160 CoroMill® Plura Small deep corner radii – 0.05 100% Dc 1 – 25 CoroMill® 316 Small deep corner radii – 0.05 100% Dc 10 – 25 CoroMill® 390 Slotting and roughing corners 5.5 12 – 80 8.5 25 – 125 CoroMill® 490 Roughing corners 08 0.15 2 mm 20 – 125 I CoroMill® 300 Slotting in difficult materials 5 ～ 20 0.15 80% iC 10 – 200 Boring 09 Materials Concept Tool holding/ Machines G Information/ Index H CoroMill® 210 First choice for roughing with long overhang Coromant plunge cutter R215 11 17 0.15 D 116 MTG09 Milling D116-D132.indd 116 2009-11-24 13:09:33 Plunge milling – how to apply General turning How to apply A Cutting process B Parting and grooving Plunge milling varies considerably from traditional milling. It uses the end of the tool to cut instead of the periphery, which beneficially changes the direction of the cutting forces from predominantly radial to axial. It can be compared to a boring operation with interrupted cuts. Power consumption and noise are low. Plunge milling = interrupted boring. Axial cutting forces. Traditional milling. Mainly radial forces. Threading C D Milling ae s Drilling E General hints Boring F G = rapid traverse Avoid re-cutting on return stroke. Gradually decrease plunge depth. Pc = 60 × 106 s x ae x vf x kc 60 × 106 H ➡ Materials Pc = D3 x ae x vf x kc ➡ I Power consumption calculation. D 117 MTG09 Milling D116-D132.indd 117 Tool holding/ Machines = program table feed Information/ Index • Horizontal machine facilitates chip evacuation. • Start milling from bottom and work up. • Use cutting fluid or compressed air to facilitate chip evacuation. • In comparison with traditional methods, plunge milling requires a lower feed per tooth. • Ensure that more than one tooth is engaged. • Use extra close pitch cutters. • Use maximum ae – depending on insert size. • Use s = 0.75 x Dc when moving sideways. • Gradually decrease plunge depth to minimize vibration. • Use a "hook program" to prevent re-cutting on the return stroke. Feed 1 mm away from wall at the end of the cut. Note: A drilling cycle is not recommended due to re-cutting which can cause vibration during retraction. • Always strive to leave a constant stock for a subsequent finishing operation. 2009-11-24 13:09:36 General turning A Parting and grooving B Plunge milling – how to apply Slots • Plunging is an effective technique for machining deep and closed slots. • Chip evacuation becomes essential. A horizontal set-up and the use of cutting fluid or compressed air will assist in this process. • A drill is recommended for deep and narrow slots, as it provides the best chip evacuation and highest step-over rate, see chapter E. C Threading Cavities/pockets Milling D • Chip evacuation is critical, just like in closed slotting. • Use a horizontal set-up and cutting fluid or compressed air. • Chip evacuation can be further improved by driling the largest possible start hole. 1.5 x Dc is recommended. • Reduce feed in the first two plunge steps. • Move sideways and try to prevent full slotting. E Drilling Corners The CoroMill Plura, CoroMill 390 end mill or the Coromant U Plunge drill (see Drilling, Chapter E) are all suitable. The drill allows cuts of up to 75% of the cutter diameter, which can be advantageous in narrow corners. Boring F Plunge milling of the remaining stock (rest milling) after a roughing operation in deep 90 degree corners can be advantageous. Tool holding/ Machines G Corner machining Dc = 12.7 mm Start radius = 16 mm Materials H End radius = 6 mm Information/ Index I D 118 MTG09 Milling D116-D132.indd 118 2009-11-24 13:09:40 A Peck milling is an alternative to ramping for opening up in solid material. B Parting and grooving Peck milling General turning Peck milling – choice of tools However, it requires excessive power, produce long chips and places undesirable cutting forces on the cutter and should therefore only be used when: • The machine lacks ramping capability • Producing short closed slots. Threading C Choice of tools D CoroMill® 316 CoroMill® 390 CoroMill® 790 Milling CoroMill® Plura 0.9 x Dc 0.55 x Dc 11: 1.0 mm 17: 1.5 mm 16: 1.1 mm 22: 1.2 mm Cutter dia. (Dc), mm 2 − 25 10 − 25 12 − 40 25 − 100 Centre cutting (drilling) Yes Yes No No P M K N S H P M K N S H P M K N S H P M K N S H Material F Boring Max. drill depth Drilling E How to apply G Centre cutting - drilling end mills (end milling cutter) Tool holding/ Machines The drill depth of a centre cutting end mill is limited by the length of the chip flute, and also by the the chip evacuation capability. For deeper slots, use a peck cycle. When drilling, use a low feed: approx. 50% of the feed recommended for milling. Note: consider ap max for full slotting milling. H Non-centre cutting end milling Materials CoroMill 390 and 790 are non-centre cutting end mills that can be used for a peck milling cycle. Note that the drill depth is very limited. Use a coarse pitch cutter for maximum chip room. D 119 MTG09 Milling D116-D132.indd 119 Information/ Index I Max. drill depth 2009-11-24 13:09:43 Slicing methods – choice of tools Slicing methods B These milling methods were originally developed for roughing and semi-roughing of difficult materials, like hard steels, ISO H, and HRSA-materials, and ISO S, but can also be used in other materials, especially in vibration sensitive applications. Parting and grooving General turning A Threading C D The techniques are based on a small radial depth of cut, ae, which: • Generates a low radial cutting force that places less demand on stability and enables a large depth of cut, ap. • Means that only one tooth is in cut at a time, which minimizes vibration tendency. • Reduces the heat in the cutting zone due to the short contact time, making it possible to use higher cutting speeds. • Generates a small chip thickness, hex, but a high feed, fz. It can be divided into: • trochoidal milling – primarily used for machining slots. • slicing – usually used for semi-roughing of corners. Milling Both these slicing methods have proven to be very secure and productive methods. Drilling E Choice of tools CoroMill® Plura CoroMill® 316 CoroMill® 490 CoroMill® 390 CoroMill® 390 Long edge cutter CoroMill® 690 Long edge cutter 7.0 − 54.0 5.5 − 13.0 5.5 15.7 71.0 112.0 Cutter dia. (Dc), mm 2 − 25 10 − 25 20 − 66 12 − 40 32 − 200 50 − 100 Material P M K N S H P M K N S P M K H P M K N S H P M K N S H S Boring F Tool holding/ Machines G Comments: • The most commonly used tool for slicing operations is the CoroMill Plura. • CoroMill 316, CoroMill 490 or CoroMill 390 are alternatives when the depth of cut is lower. • The slicing technique can also be used with long edge cutters that combine small ae with large ap. Materials H Max. cutting depth (ap), mm Information/ Index I D 120 MTG09 Milling D116-D132.indd 120 2009-11-24 13:09:45 Slicing methods – how to apply General turning How to apply A Parting and grooving B C Effect Benefit • Thin chip thickness • Small arc of engagement • Lower cutting force/deflection • Reduced temperature at cutting zone • Deeper axial cuts • Higher speeds D Milling Factor Threading Slicing uses a higher cutting speed, vc, and an axial cut, ap, but with only small radial engagements, ae, and feed per tooth, fz. This is possible due to: Trochoidal milling E Application area Drilling An excellent method for slotting when vibration is a problem; it is also suitable for rough milling of confined cavities, pockets and grooves. Definition Trochoidal milling can be defined as circular milling that includes simultaneous forward movements. The cutter removes repeated "slices“ of material in a sequence of continuous spiral tool paths in its radial direction. F It requires specialized programming and machine tool capabilities. Boring The tool is programmed with a roll entry into and exit from cut, with the radial pitch, w, kept low, which means that: • The controlled arc of engagement generates low cutting forces, which enable high axial depths of cut. • The whole cutting edge length is utilized, ensuring that the heat and wear are uniform and spread out, leading to longer tool life than traditional slot milling. • Due to the short arc of engagement, multi-edge tools are used, which enable high table feeds with secure tool life. • The maximum radial cut, ae, should not exceed 20% of the cutter diameter. Tool holding/ Machines G H ap ≤ 2 x Dc Materials ae = small vf = high Namnlöst-1 1 vc = up to 10 times that of conventional methods D 121 MTG09 Milling D116-D132.indd 121 Information/ Index I 2009-11-24 13:09:47 Slicing methods – how to apply For groove widths less than 2 x Dc B Considerations Parting and grooving General turning A 1) The radial cut is constantly changing and, at the greatest immersion, it is higher than the programmed step over, w. 2) It is important to keep the cutter diameter to a slot width ratio below 70%, and the radial pitch, w, below 10% of Dc. 3) The feed is constant, however, the tool centre feed, vf, varies from the periphery feed, vfm. When the feed is programmed based on the tool centre, then the peripheral feed must be calculated. Threading C max The tool is programmed on a continuous spiral path that feeds in the radial direction to form a groove or a profile. The feed is constant, with a continuously varying radial cut. 50% of the time the tool is out of cut. D vfm = n × fz × zn Milling Cutting parameters E • Max. cutter dia • Step over • Radial cut max. Dc = 70% slot width w = max. 10% Dc ae = 20% Dc • Axial cut • Start feed per tooth ap = up to 2 x Dc fz = 0.1 mm Dvf = Dm – Dc vf = Calculate programmed feed vf Dvf Dm × vfm 1 – Narrow groove – Inconel 718 (44HRC) Number of slots/component 24 Width 12 mm Length 25 mm Depth 16 mm Boring Drilling Machining cases using trochoidal milling Tool life 10 slots Time/slot 1'35" G Tool – R216.24-08050-EAK 19P 1620 12 8 Depth of cut ap 16 mm Tool centre dia. Dvf 4 mm Tool holding/ Machines 0.8 Cutter dia. Dc 8 mm Step over w 0.67 mm Number of teeth zn 4 Feed per tooth fz 0.09 mm Cutting speed vc 75 m/min Periphery feed vfm 1047 mm/min H Spindle speed n 2984 m/min Tool centre feed vf 349 mm/min Materials F Trochoidal milling provides a far more secure process, when compared to traditional slotting or plunging, with increased tool life and reduced tooling costs, as a 12 mm tool replaces a 8 mm tool. Information/ Index I D 122 MTG09 Milling D116-D132.indd 122 2009-11-24 13:09:49 A General turning Slicing methods – how to apply For grooves wider than 2 x Dc A continuous spiral path, such as those programmed for the narrow groove where 50% of the time is spent with the tool out of the cut, can be optimized as the groove, becomes wider: B Parting and grooving 1. Roll into cut – programmed radius (radm) = 50% of Dc. 2. G1 with ae = 0.1 x Dc. 3. Roll out of cut – programmed radius (radm) = 50% of Dc. 4. Rapid movement to next start position. 5. Repeat cycle. C Cutting parameters • Radial depth – CoroMill Plura – CoroMill 390/490 ae = 10% Dc ae = 20% Dc Groove width Threading ap = up to 2 x Dc fz = 0.1 mm radfv = 0.5 x G1 • Axial cut • Start feed per tooth • Radius feed D 2 – Wide groove – Scallop Ø8 8 Width 45 mm Depth 16 mm Thickness 4 mm 45 15 10 rad Milling Number of slots/component E Tool 2 – CoroMill Plura – Ø 12 mm R390-016A16-11H R390-11T308M-PL 1030 R216.24-12050AK26P 1620 Drilling Tool 1 – CoroMill 390 – Ø 16 mm F a) Stainless steel – 316 zn vc n fz vf ap ae m/min r/min mm mm/min mm mm Q Time cm³/min min+sec CoroMill 390 16 2 200 3978 0.15 1194 5 2 11.9 0'25'' CoroMill Plura 12 4 170 4509 0.06 1082 5 1 5.4 1'00'' zn vc n fz vf ap ae Q m/min r/min mm mm/min mm mm Boring Diameter, Dc mm G b) HRSA – Inconel 718 (44 HRC) Diameter, Dc mm Time cm³/min min+sec CoroMill 390 16 2 30 597 0.10 119 5 2 1.2 2'45'' CoroMill Plura 12 4 75 1989 0.08 637 5 1 3.2 1'15'' Tool holding/ Machines Tool H CoroMill® 390 vs CoroMill® Plura • Stainless steel – CoroMill 390 offers the fastest time – 140% faster than CoroMill Plura. In stainless steel, the CoroMill 390 performed without material "clogging" or jamming in the flutes, which allowed for a faster radial cut, ae, and higher feed per tooth, fz, than the CoroMill Plura. • HRSA – CoroMill Plura was 120% faster than CoroMill 390. In the harder HRSA, the extra teeth and high helix of the CoroMill Plura produced a much smoother operation. Materials Tool D 123 MTG09 Milling D116-D132.indd 123 Information/ Index I 2009-11-24 13:09:54 General turning A Parting and grooving B Threading C Slicing – corner milling Application area Slicing is a semi-roughing technique used in corner milling where the larger tool used in the previous operation could not reach. Definition Unlike trochoidal milling, no roll into or from cut is required, as the radial cut builds from zero to a maximum in the middle, and then drops back to zero again. Multiple passes successively remove material, ensuring consistent low radial immersion/engagement angle and low cutting forces. Considerations: Feed rate reduction in corners: • As with all radius contouring, when programming with a tool centre feed, vf, the feed rate needs to be reduced relative to the tool periphery feed, vfm, to maintain a constant feed per tooth. • Depth of cut can become too great to be able to run at same high feed as with straight line cutting, depending upon cutter diameter to corner radius relationship. • However, the ratio between programmed cutter path diameter, Dvf, and hole diameter, Dm, is constantly increasing towards the finished corner radius; which means that the feed needs to continually decrease for each pass. • Process becomes unstable and vibration occurs. • A machine tool with good dynamic stability and tool centre feed reduction control is essential for successful milling of internal corners. Slicing Dvf = Dm – Dc E Drilling vf = Dvf and vf continually decreased for each pass F radw radm ae max Boring Conventional vfm = n × fz × zn Milling D Slicing methods – how to apply ae max θ Dc G Dvf radw (20 mm) w ae tot θ Dc × vfm Angle of corner radw radm fin. rad Dvf Dm radw (20 mm) radm (6 mm) w θ radm (6 mm) Namnlöst-1 1 Dvf w = radial step over radm = component end radius radw = component start radius H Cutting parameters Materials Tool holding/ Machines ae tot Typical values for a CoroMill Plura R216.24-xxx50-xxK xxP • Maximum cutter diameter Dc = 1.75 x radm • Radial step over w = 10% Dc • High axial cut ap = up to 2 x Dc • Start feed per tooth fz = 0.1 mm • Cutting speed – approx. 3-6 times the normal recommendation. ae tot = 5.8 mm ae tot = 14 mm For the same start and end radii, the number of passes required will vary depending upon the corner angle. For corners with angles less than 60˚, plunging using the CoroMill 390 or a plunge drill can be a good solution, see page D 118. Information/ Index I D 124 MTG09 Milling D116-D132.indd 124 2009-11-24 13:09:56 A Closed angles, less than 90 degrees, are a common component feature in pockets and cavities. A machine with 4- or 5-axes is needed to machine a closed angle. B Parting and grooving Closed pockets/angles General turning Closed pockets/angles – choice of tools 4-axes: If only one side of the pockes has a closed angle and the bottom shape is flat. 5-axes: If there is a corner with closed angles on both sides. If there is a radius at the bottom profile. Threading C Choice of tools D Milling CoroMill® Plura Max. cutting depth (ap), mm 10.0 – 45.0 Cutter dia. (Dc), mm 3.8 – 15.18 Material P M K N S H Drilling E Milling of a blisk impellar is one application example of milling closed angles. F Boring How to apply Machining recommendation G 1. Prior to the radius machining, shoulder milling of the wall should be performed with a square end mill for best stability. Tool holding/ Machines 2. The radius is machined with a ball nose end mill. H Materials Use a square end mill for best stability when machining the peripheral wall. 2009-08-31 09:29:34 The final machining of the radius should be performed with a conical ball nose end mill. I D 125 MTG09 Milling D116-D132.indd 125 Information/ Index Namnlöst-1 1 2009-11-24 13:10:00 Chamfering – choice of tools Chamfering B Chamfers, V-cuts, undercuts, preparation for welding, and deburring operations along the workpiece edges are frequent operations. Depending upon the type of machine and set-up, these operations can be performed in a varity of ways. A small face mill, a long edge cutter, an end mill or a dedicated chamfering cutters can be used. Parting and grooving General turning A Threading C D Choice of tools CoroMill® 316 CoroTurn® XS CoroMill® 327 CoroMill® 328 U-Max 30, 45, 60 15, 30, 45, 60 30 45, 60 60 45, 60 Max. chamfer depth 7.4 6.5 0.6 1.7 1.8 7.9 F Back chamfering min. hole diameter (mm) – – 6 12 40 27 P M K N S H P M K N S P M N S P M K N S H P M K N S H P M K N S H Milling CoroMill® Plura Drilling Dedicated chamfering cutters E Entering angle (degrees) Boring Material G Complementary cutters for chamfering Tool holding/ Machines In 4- and 5-axes machines, where the spindle or the workpiece can be tilted, a number of tools can be used for chamfering and deburring such as: Materials H • 90 degree end mills such as CoroMill Plura, CoroMill 316, CoroMill 390, CoroMill 490, CoroMill 790 • 45 degree face mills such as CoroMill 245 and CoroMill 345 • For large chamfers, long edge cutters can be used. Information/ Index I D 126 MTG09 Milling D116-D132.indd 126 2009-11-24 13:10:04 Chamfering – how to apply General turning How to apply A Cutting data B Parting and grooving Normally the depth of cut, ap, and width of cut, ae, are small in relation to the cutter diameter. This means the higher cutting speed recommendations for small engagement should be used. The feed per tooth, fz, can also be considerably increased, see page D 21. The demands of the surface finish limit fz. Threading C D Chamfering a hole Milling With CoroMill 327, CoroMill 328 and CoroTurn XS, it is possible to chamfer the hole after completing the threading operation, using the same tool and insert. This is performed using a circular milling path, see the programming sequence below. Drilling E Boring F 1. Position the cutter centrally over the drilled hole, with the cutter rotating, and move axially to flange depth (Z = flange height – chamfer size). 3. Interpolate 360° 4. Feed back to hole centre Zero point for tool length and radius. Tool holding/ Machines G H 5. Retract cutter Materials 2. Feed the cutter to engage with the radius compensation (Y = hole radius). Note: To adjust chamfer size, alter Z position (do not adjust diameter as this can cause rubbing on the hole). D 127 MTG09 Milling D116-D132.indd 127 Information/ Index I 2009-11-24 13:10:06 General turning A Parting and grooving B Trouble shooting Tool wear Look at the edge, analyze the wear and optimize the cutting data from your conclusion. Cause Solution Rapid wear causing poor surface finish or out of tolerance. • Reduce cutting speed, vc • Select a more wear-resistant grade • Increase feed, fz Flank wear • Cutting speed too high • Insufficient wear resistance • Feed, fz, too low Threading C Milling – trouble shooting D Excessive wear causing short tool life. Milling • Vibration • Re-cutting of chips • Burr formation on component • Poor surface finish • Heat generation • Excessive noise E Uneven wear causing corner damage. Drilling • Tool run-out • Vibration • Short tool life • Bad surface finish • High noise level • Radial forces too high Boring F • Reduce run-out below 0.02 mm • Check chuck and collet • Minimize tool protrusion • Fewer teeth in cut • Larger tool diameter • For CoroMill Plura and CoroMill 316, select a higher helix geometry (gp ≥45°) • Split axial cutting depth, ap, into more than one pass • Reduce feed, fz • Reduce cutting speed, vc • HSM requires shallow passes • Improve clamping of tool and workpiece Crater wear Excessive wear causing a weakened edge. Cutting edge breakthrough on the trailing edge causes poor surface finish. G • Diffusion wear due to cutting temperatures that are too high on the rake face Tool holding/ Machines • Increase feed, fz • Down milling • Evacuate chips effectively using compressed air • Check recommended cutting data • Select an Al203 coated grade • Select a positive insert geometry • First reduce the speed to obtain a lower temperature, and then reduce the feed Plastic deformation Plastic deformation of edge, depression or flank impression, leading to poor chip control, poor surface finish and insert breakage. H • Select a more wear resistant (harder) grade • Reduce cutting speed, vc • Reduce feed, fz Materials • Cutting temperature and pressure too high Information/ Index I D 128 MTG09 Milling D116-D132.indd 128 2009-11-24 13:10:07 Cause Solution The part of the cutting edge not in cut is damaged by chip hammering. Both the top side and the support for the insert can be damaged, leading to poor surface texture and excessive flank wear. • Select a tougher grade • Select an insert with a stronger cutting edge • Increase cutting speed, vc • Select a positive geometry • Reduce the feed at the beginning of cut • Improve stability Chipping Small cutting edge fractures (frittering) causing poor surface finish and excessive flank wear. • Select a tougher grade • Select an insert with a stronger geometry • Increase cutting speed, vc, or select a positive geometry • Reduce feed at the beginning of the cut C Threading • Grade too brittle • Insert geometry too weak • Built-up edge B Parting and grooving • The chips are deflected against the cutting edge A General turning Milling – trouble shooting D Notch wear Notch wear causing poor surface finish and risk of edge breakage. Milling • Work hardening materials • Skin and scale • Reduce cutting speed, vc • Select a tougher grade • Increase cutting speed, vc Thermal cracks Small cracks perpendicular to the cutting edge causing frittering and poor surface finish. E Drilling Thermal cracks due to temperature variations caused by: • Intermittent machining • Varying cutting fluid supply • Select a tougher grade with better resistance to thermal shocks • Cutting fluid should be applied copiously or not at all, for more information, see Getting started, page D 28. F Built-up edge (B.U.E) Built-up edge causing poor surface finish and cutting edge frittering when the B.U.E. is torn away. • Increase cutting speed • Change to a more suitable insert geometry Boring • Cutting zone temperature is too low. • Very sticky material, such as low-carbon steel, stainless steels, and aluminium. G • Low cutting speed, vc • Low feed, fz • Negative cutting geometry • Poor surface finish • Increase cutting speed, vc • Increase feed, fz • Select a positive geometry • Use oil mist or cutting fluid Tool holding/ Machines Workpiece material is welded to the cutting edge due to: Materials H D 129 MTG09 Milling D116-D132.indd 129 Information/ Index I 2009-11-24 13:10:07 General turning A Milling – trouble shooting Cause Solution Vibration (see also Getting started, page D 30) • Weak fixture • Assess the direction of the cutting forces and provide adequate support or improve the fixture • Reduce the cutting forces by decreasing the cutting depth, ap • Select a coarse and differentially pitched cutter with a more positive cutting action • Select a L-geometry with a small corner radius and small parallel land • Select a fine-grain, uncoated insert, or a thinner coating • Avoid machining where the workpiece has poor support against the cutting forces • Axially weak workpiece • Consider a square shoulder cutter (90-degree entering angle) with positive geometry • Select an insert with L-geometry • Decrease axial cutting force – lower depth of cut, smaller corner radius and parallel land • Select a coarse-pitch cutter with differential pitch • Check tool wear • Check tool holder run-out • Improve clamping of tool • Too long tool overhang • Minimize overhang • Use coarse-pitch cutters with differential pitch • Balance radial and axial cutting forces – 45 degree entering angle, large corner radius or round insert cutter • Increase feed per tooth • Use a light-cutting insert geometry – L/M • Reduce axial depth of cut, af • Use up-milling in finishing • Use oversize cutters and Coromant Capto coupling adaptors • For CoroMill Plura and CoroMill 316, try a tool with fewer teeth and/or a higher helix angle • Milling square shoulder with weak spindle • Select smallest possible cutter diameter • Select positive and light cutting cutter and insert • Try up-milling • Check spindle deflection to see if acceptable for machine • Irregular table feed • Try up-milling • Tighten machine feed mechanism: adjust the feed screw on CNC machines. Adjust the locking screw or replace the ball screw on conventional machines. • Cutting data • Reduce cutting speed, vc • Increase feed, fz • Change cutting depth, ap • Bad stability • Reduce overhang • Better stability • Vibration in corners • Program large corner radii with reduced feed rate Parting and grooving B Threading C Milling D Drilling E Boring F Tool holding/ Machines G Materials H Information/ Index I D 130 MTG09 Milling D116-D132.indd 130 2009-11-24 13:10:07 Solution Common obstacle when full slotting – especially in long-chipping materials • Improve chip evacuation by using rich and well directed cutting fluid or compressed air • Reduce feed, fz • Split deep cuts into several passes • Try up-milling in deep slotting • Use coarse pitch cutters • Use CoroMill Plura and CoroMill 316 with two or maximum three cutting edges and/or a higher helix angle Chip jamming • Insert corner damage • Edge chipping and breakage • Re-cutting of chips General turning Cause A B Parting and grooving Milling – trouble shooting C Appears in full slotting and pocketing – especially in titanium. Also common when milling deep cavities and pockets on vertical machines. D Milling • Cutting edge fractures • Harmful for tool life and security • Chip jamming • Evacuate chips effectively by compressed air or copious cutting fluid flow – preferably supplied internally through the tool • Change cutter position and tool path strategy • Reduce feed, fz • Split deep cuts into several passes Threading Re-cutting of chips Unsatisfactory surface finish E • Set cutter axially or classify inserts. Check height with indicator • Check spindle run-out and cutter mounting surfaces • Decrease feed per rev to max. 70% of the width of the parallel land • Use wiper inserts if possible (finishing operations) • Vibration • See section “Vibration” • Built-up edge formation • Increase cutting speed, vc, to elevate machining temperature • Turn off cutting fluid • Use sharp cutting edge inserts, with smooth rake side • Use positive insert geometry • Try a cermet grade with higher cutting data • Back-cutting • Check spindle tilt (Tilt spindle approx 0.10 mm/1000 mm) • Axial run-out TIR of spindle should not exceed 7 microns during finishing • Reduce the radial cutting forces (decrease the depth of cut, ap) • Select a smaller cutter diameter • Check the parallelism on the parallel lands and on wiper insert used (should not be standing on ”heel or toe”) • Make sure the cutter is not wobbling – adjust the mounting surfaces Drilling • Excessive feed per revolution Boring F Tool holding/ Machines G H • Decrease feed, fz • Select a close or extra-close pitch cutter • Re-position the cutter to give a thinner chip at cutter exit • Select a more suitable entering angle (45-degrees) and lighter cutting geometry • Choose a sharp insert • Monitor flank wear to avoid excessive wear Materials • Workpiece frittering D 131 MTG09 Milling D116-D132.indd 131 Information/ Index I 2009-11-24 13:10:08 A Milling – trouble shooting General turning Cause Burr formation • Material specific – HRSA/stainless steel • Notch main wear mechanism Parting and grooving B • Use large radius giving low insert entry angle • Keep depth of cut below radius • CoroMill 300 – maximum ap = 0.25 x iC • CoroMill 390 radius inserts – max. • ap = 0.5 x radius Machine power Be aware of the power curve as the machine may lose efficiency if the rpm is too low. The power requirements in milling vary with the: • Amount of metal to removed • Average chip thickness • Cutter geometry • Cutting speed. Threading C Solution D • Go from close to coarse pitch, i.e. fewer teeth • A positive cutter is more power efficient than a negative cutter • Reduce cutting speed before table feed • Use a smaller cutter and make several passes • Reduce depth of cut, ap Milling For more information about power and torque, see Getting started, page D 11. Drilling E Boring F Tool holding/ Machines G Materials H Information/ Index I D 132 MTG09 Milling D116-D132.indd 132 2009-11-24 13:10:09 General turning A Parting and grooving B Milling – grade information Grade information The cutting tool materials are generally divided into basic and complementary grades, indicated in an ISO/ANSI chart, and are described by the relation between wear resistance and toughness. • Basic grades cover a wide range of applications and should be the first choice. • Complementary grades contribute to widths and other alternatives within the range. Threading The position and form of the grade symbols indicate the suitable field of application = Basic grades  C Centre of the field of application Recommended field of application Wear resistance Toughness = Complementary grades D Steel Complementary grades Milling Basic grades Drilling E Boring F Tool holding/ Machines G GC1030 (HC) – P30 (P25 – P50) GC2030 (HC) – P25 (P15 – P35) • All-round grade for modern machining with a good balance of security and productivity. Coated carbide grade for light to heavy milling (both wet and dry) in unalloyed and low alloyed steels. First choice in face milling and an optimizer for higher productivity in shoulder milling. • PVD coated carbide grade. GC1030 is the first choice in unstabl conditions such as long edge, chip jamming, deep shoulder and end milling, long overhang, turn mill operations, etc. Can be used as a backup choice in tough operations. In combination with periphery ground inserts, the first choice for sticky materials, e.g. low carbon steel. • PVD coated carbide grade for milling of low carbon steels that tend to create built-up edge. Also very suitable for 90 degree milling in mixed materials. GC4220 (HC) – P15 (P05-P25) • Coated carbide grade optimized for best produc tivity in steel milling. Grade for dry machining with high chip removal rate. GC4240 (HC) – P40 (P30 – P50) • Tough coated carbide grade for demanding operations in steel milling. For end mill and square shoulder concepts, grade GC4240 should be used in more stable conditions, such as short overhangs, face milling, shallow shoulder milling, etc. For other concepts, grade GC4240 is the first or backup choice in tough operations. Benefits of security. Suitable for small batch production of mixed material. Workes well both with or without coolant. GC1025 (HC) – P10 (P05 – P20) • PVD coated carbide grade for light milling of steel. In combination with periphery ground inserts, the first choice for sticky materials, e.g. low carbon steels. CT530 (HT) – P20 (P05 – P30) • Cermet grade for light milling operations, mainly without coolant. The high resistance to plastic deformation and smearing/built-up edge make it suitalble for a wide cutting speed range. Ideal grade for Wiper inserts. GC2040 (HC) – P40 (P30 – P50) • Coated carbide grade for milling of steels, when a combination of sharp cutting edges and a tough grade is needed at low speeds. Very useful for small batch production of mixed materials. GC3040 (HC) – P20 (P10 – P30) • Coated carbide grade with very good abrasive wear resistance, for rough milling of steel at medium to high speeds. SM30 (HW) – P30 (P20 – P40) • Uncoated carbide grade for medium to rough milling at low to moderate cutting speeds. Good edge security in hard materials and in unstable conditions. GC1010 (HC) – P10 (P05-P30) • PVD coated carbide grade for milling within application area of typical pre-hardened and plastic mould steel, from 36 HRc and above. Materials H GC4230 (HC) – P25 (P10-P40) Information/ Index I D 188 MTG09 Milling D182-D197.indd 188 2009-11-24 13:30:25 Hardmetals: HW ncoated hardmetal containing primarily U tungsten carbide (WC). HT ncoated hardmetal, also called cermet, U containing primarily titanium carbides (TIC) or titanium nitrides (TIN) or both. Ceramics: Diamond: CA xide ceramics containing primarily O aluminium oxide (Al2O3). DP CM ixed ceramics containing primarily aluminium M oxide (Al2O3) but containing components other than oxides. CN itride ceramics containing primarily silicon N nitride (Si3N4). CC Ceramics as above, but coated. Polycrystalline diamond ¹) Boron nitride: Cubic boron nitride ¹) BN 1) Polycrystalline diamond and cubic boron nitride are also called super-hard cutting materials. HC Hardmetals as above, but coated. B Parting and grooving Letter symbols specifying the designation of hard cutting materials: A General turning Milling – grade information P ISO P = Steel N ISO N = Non-ferrous material M ISO M = Stainless steel S ISO S = Heat resistant super alloys K ISO K = Cast iron H ISO H = Hardened steel Threading C D Austenitic/martensitic stainless steel Complementary grades Milling Basic grades Drilling E GC1025 (HC) – M15 (M10 – M20) GC2040 (HC) – M30 (M20 – M40) SM30( HW) – M30 (M25 – M35) • PVD coated carbide grade for light milling of stainless steel. In combination with periphery ground inserts, the first choice for sticky and workhardening materials. • Coated carbide grade for milling of stainless steels with abrasive tendencies, e. g. cast components, ferritic/martensitic stainless steels and PH-steels at medium speeds. Also useful for small batch production of mixed materials. • Uncoated carbide grade for medium to rough milling at low to moderate cutting speeds. Good edge security in unstable conditions. • PVD coated carbide grade for light milling of stainless steel. In combination with periphery ground inserts, the first choice for sticky and workhardening materials. GC2030 (HC) – M25 (M15 – M35) • Coated carbide grade for light to heavy milling in martensitic stainless steels. • Coated carbide grade for medium to heavy operations in stainless steel castings. Very suitable for small batch production of mixed materials. G CT530 (HT) – M20 (M10 – M30) • Cermet grade for light milling of austenitic/duplex stainless steels. The high resistance to plastic deformation/smearing/built-up edge makes it suitable for a wide cutting speed range in dry conditions. H Materials • PVD coated carbide grade for milling of stainless steels (mainly austenitic types) at medium to high speeds. In combination with positive geometries, also suitable for heat resistant material and titanium. GC4240 (HC) – M40 (M20 – M40) Tool holding/ Machines GC1030 (HC) – M15 (M10 – M20) GC4230 (HC) – M15 (M10 – M25) Boring F D 189 MTG09 Milling D182-D197.indd 189 Information/ Index I 2009-11-24 13:30:26 General turning A Milling – grade information Cast iron Basic grades Complementary grades Parting and grooving B Threading C D GC3040 (HC) – K30 (K20 – K40) K20W (HC) K25 (K15-K35) H13A (HW) – K25 (K15 – K30) • Tough coated carbide grade for demanding milling of cast iron e.g. nodular cast iron, wet conditions or high tensile iron. Long predictable tool life at low to medium cutting speeds. • Coated carbide grade for medium to rough milling of grey cast iron under wet conditions. To be used at low to medium speeds. • Uncoated carbide grade with wear resistance and toughness for light to medium milling at moderate cutting speeds. Ideal choice for milling of ferritic nodular cast iron. K15W (HC) – K15 (K10 – K25) GC3220 (HC) – K20 (K05 – K25) • CVD coated carbide grade for medium to rough milling of grey cast iron, mainly under dry conditions. Long predictable tool life at medium to high cutting speeds. GC1020 (HC) – K20 (K15 – K35) Milling • PVD coated carbide grade for medium to rough milling of grey and nodular cast iron under wet conditions. To be used at medium to high speeds with predictable tool life. • CB50 is a cubic boron nitride tipped grade. It provides a high edge toughness combined with good wear resistance. CB50 is well suited for machining of cast iron under favourable conditions. CC6190 (CN) – K15 (K05 – K20) • Silicon nitride ceramic grade for roughing to semifinishing of grey cast iron at high cutting speeds. K20D (HC) - K20 (K10-K30) • MTCVD coated grade for medium to rough milling of cast iron. Mainly without coolant. Long tool life with high speed capability. H1P (HW) – K05 (K01 – K10) • Uncoated carbide grade for finishing of cast iron, bronze and brass. Also suitable for wiper inserts. GC1010 (HC) – K10 (K05-K25) • PVD-coated carbide grade for finishing milling in grey and nodular cast iron. A long tool life can be predicted with a sustained surface finish. GC4220 (HC) – K25 (K15 – K30) • Coated carbide grade for light to heavy milling of cast iron at medium speeds. To complement GC3000 grades in operations. GC4230 (HC) – K30 (K25 – K35) • Coated carbide grade for light to heavy milling of nodular cast iron. GC4240 (HC) – K35 (K30 – K40) • Coated carbide grade for medium to heavy operations at low speeds where the demand for toughness is high. Drilling E CB50 (BN) – K05 (K01 – K10) • Coated carbide grade for milling of grey cast iron under wet conditions. To be used at medium speeds. F Non-ferrous metals, plastics, wood Complementary grades Boring Basic grades Tool holding/ Machines G CD10 (DP) – N05 (N01 – N10) CT530 (HT) – N15 (N10 – N25) H10F (HW) – N20 (N15 – N25) • Polycrystalline diamond tipped grade for machining of non-ferrous and non-metallic materials. Provides long tool life, clean cut and good surface finish. Cermet grade mainly recommended at high RPM when milling aluminium due to the low tendency for built-up edge and low weight of the inserts. Uncoated carbide grade suitable for milling aluminium alloys in combination with "sharp" cutting edges. H H10 (HW) – N10 (N05 – N15) GC1025 (HC) – N15 (N10 – N25) • Uncoated fine-grained carbide grade, that provides excellent edge sharpness for milling aluminium. PVD coated carbide grade for rough milling of aluminium alloys in combination with ground cutting edges. GC1030 (HC) - N15 (N10-N25) PVD coated carbide grade for rough milling of aluminium alloys in combination with ground cutting edges. Materials H13A (HW) – N15 (N10 – N20) • Uncoated carbide grade suitable for milling aluminium alloys in combination with "sharp" cutting edges. Information/ Index I D 190 MTG09 Milling D182-D197.indd 190 2009-11-24 13:30:26 Milling – grade information Basic grades General turning Heat-resistant alloys/Titanium alloys A Complementary grades Parting and grooving B GC1025 (HC) – S15 (S10 – S20) GC2030 (HC) – S25 (S15 – S35) GC2040 (HC) – S30 (S20 – S40) • PVD coated carbide grade for milling heat resistant super alloys at medium speeds. Good resistance to built-up edge and plastic deformation. • PVD coated carbide grade for semi-finishing to light roughing of heat resistant super alloys at low speeds. • Coated carbide grade for milling of cast heatresistant alloys. H10F (HW) – S30 (S25 – S35) GC1030 (HC) – S15 (S10 – S20) • Uncoated carbide grade with fine grain sizes. High notch wear resistance makes it suitable for milling of aerospace materials, e.g. titanium. • PVD coated carbide grade for milling of heat resi stant super alloys at medium speeds. Good resi stance to built-up edge and plastic deformation. C • Uncoated carbide grade with good abrasive wear resistance and toughness for milling heat resistant alloys at moderate cutting speeds and feeds. Threading H13A (HW) – S20 (S15 – S25) D Basic grades Milling Hardened steel Complementary grades Drilling E GC1030 (HC) - H10 (H10-H20) GC3040 (HC) – H25 (H20 – H30) • CB50 is a cubic boron nitride tipped grade. It provides a high edge toughness combined with good wear resistance. CB50 is well suited for machining hardened steel under favorable conditions. • PVD coated carbide grade for milling hardened components at low feeds and moderate speeds. • Coated carbide grade for rough milling hardened steel at fair conditions and low to medium speeds. GC4220 (HC) – H25 (H15 – H30) GC1025 (HC) – H15 (H10 – H20) • Coated carbide grade for light roughing under favorable conditions of hardened steels, up to HRc 60. Can handle high temperatures. • PVD coated carbide grade for milling hardened components at low feeds and moderate speeds. CC6190 (HC) – H10 (H05 – H15) • Silicon nitride ceramic grade suitable for semifinish milling of chilled cast iron at medium to high speeds. GC1010 (HC) – H10 (H05-H25) H1P (HW) – H10 (H05 – H15) CT530 (HT) – H25 (H10 – H25) • Cermet grade for finish milling of hardened steel components at low to medium speeds. • Uncoated carbide grade for finishing chilled cast iron at medium speeds. G Tool holding/ Machines • PVD-coated carbide grade for machining in hardened steel. Can handle large portion of machining demands, from roughing to finishing operations. Due to exeptional plastic deformation resistance, thermal crack resistance and good wear resistance, the grade can withstand long periods in cut. Suitable for machining hardened steel from 36 HRc and above. Boring F CB50 (BN) – H05 (H01 – H10) Materials H D 191 MTG09 Milling D182-D197.indd 191 Information/ Index I 2009-11-24 13:30:26 General turning A Parting and grooving B Milling – feed recommendations Shoulder milling κr = 90° Insert geometry CoroMill® 490 M-PL M-PM M-PH E-ML E-MM M-MM Max. chip thickness, hex (mm) Starting value (min.- max.) Starting value (min.- max.) 0.10 0.17 0.22 (0.05 – 0.15) (0.10 – 0.20) (0.15 – 0.25) 0.10 0.17 0.22 (0.05 – 0.15) (0.10 – 0.20) (0.15 – 0.25) 0.15 0.17 0.17 (0.12 – 0.18) (0.15 – 0.20) (0.15 – 0.20) 0.15 0.17 0.17 (0.12 – 0.18) (0.15 – 0.20) (0.15 – 0.20) 0.10 0.17 0.25 (0.05 – 0.15) (0.10 – 0.20) (0.15 – 0.30) 0.10 0.17 0.25 (0.05 – 0.15) (0.10 – 0.20) (0.15 – 0.30) R490 Threading CoroMill® 390 D Milling R390 Drilling E Boring F CoroMill® 290 E-PL E-ML E-KL E-NL Light 11 0.08 0.10 0.08 0.20 (0.05 – 0.12) (0.05 – 0.15) (0.05 – 0.12) (0.10 – 0.30) 0.08 0.10 0.08 0.20 (0.05 – 0.12) (0.05 – 0.15) (0.05 – 0.12) (0.10 – 0.30) M-PL M-KL Light 11 0.08 0.10 (0.05 – 0.15) (0.08 – 0.15) 0.08 0.10 (0.05 – 0.15) (0.08 – 0.15) E-PL E-ML E-KL E-NL Light 17 0.08 0.10 0.08 0.20 (0.05 – 0.12) (0.05 – 0.15) (0.05 – 0.12) (0.10 – 0.30) 0.08 0.10 0.08 0.20 (0.05 – 0.12) (0.05 – 0.15) (0.05 – 0.12) (0.10 – 0.30) M-PL M-KL E-PM E-MM E-KM Light 17 0.08 0.10 0.10 0.13 0.12 0.10 0.13 0.12 (0.05 – 0.15) (0.08 – 0.15) (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) 0.08 0.10 0.10 0.13 0.12 0.10 0.13 0.12 (0.05 – 0.15) (0.08 – 0.15) (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) 0.10 0.15 0.15 0.10 0.15 0.15 (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) 0.10 0.15 0.15 0.10 0.15 0.15 (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) (0.08 – 0.15) (0.08 – 0.20) (0.12 – 0.20) Tool holding/ Machines R290 rε = 0.8 R290.90 rε = 2.0 Materials 11 Medium E-PM E-MM E-KM M-PM M-MM M-KM M-PH M-MH M-KH Medium Heavy 11 0.12 0.16 0.15 (0.08 – 0.20) (0.08 – 0.22) (0.12 – 0.22) 0.12 0.16 0.15 (0.08 – 0.20) (0.08 – 0.22) (0.12 – 0.22) M-PH M-KH H-PL H-ML H-KL Heavy 17 Light 18 0.20 0.20 0.10 0.10 0.10 (0.15 – 0.35) (0.15 – 0.35) (0.05 – 0.19) (0.05 – 0.19) (0.05 – 0.19) 0.20 0.20 0.10 0.10 0.10 (0.15 – 0.35) (0.15 – 0.35) (0.05 – 0.19) (0.05 – 0.19) (0.05 – 0.19) M-PM M-MM M-KM Medium 18 E PCD 11 0.20 0.20 0.20 0.15 (0.08 – 0.30) (0.08 – 0.30) (0.08 – 0.30) (0.10 – 0.25) 0.20 0.20 0.20 0.15 (0.08 – 0.30) (0.08 – 0.30) (0.08 – 0.30) (0.10 – 0.25) E PCD 17 0.15 (0.10 – 0.25) 0.15 (0.10 – 0.25) M-PL M-KL Light 0.08 0.10 (0.05 – 0.15) (0.08 – 0.15) 0.08 0.10 (0.05 – 0.15) (0.08 – 0.15) 0.06 0.08 0.10 (0.05 – 0.09) (0.07 – 0.12) (0.08 – 0.15) 0.06 0.08 0.10 (0.05 – 0.09) (0.07 – 0.12) (0.08 – 0.15) 0.17 (0.10 – 0.20) 0.17 (0.10 – 0.20) Medium } M-PM M-KM M-KM M-PL M-ML M-KL M-WL M-PM M-MM M-KM M-WM M-PH M-KH M-WH I Medium M-PM M-MM M-KM E-PL E-KL E-ML H Information/ Index 08 M-KL M-KM M-KH C G Insert size Feed per tooth, fz (mm/tooth) 11 17 17 Light 12 Medium 12 Light 12 0.17 (0.10 – 0.20) 0.17 (0.10 – 0.20) Medium 12 0.12 (0.08 – 0.15) 0.12 (0.08 – 0.15) Heavy 12 0.25 (0.10 – 0.30) 0.25 (0.10 – 0.30) E Ceramic 0.10 (0.05 – 0.15) 0.10 (0.05 – 0.15) E CBN 0.10 (0.05 – 0.18) 0.10 (0.05 – 0.18) D 192 MTG09 Milling D182-D197.indd 192 2009-11-26 08:34:18 κr = 90° Feed per tooth, fz (mm/tooth) Max. chip thickness, hex (mm) Insert size Starting value (min.- max.) Starting value (min.- max.) M-P-SL M-E-SL 10 0.10 (0.05 – 0.2) 0.10 (0.05 – 0.15) M-P-SL M-E-SL 14 0.12 (0.05 – 0.2) 0.12 (0.05 – 0.15) Insert geometry CoroMill® 690 General turning Shoulder milling A B Parting and grooving Milling – feed recommendations C -ML2 -ML 18*/19 0.15 (0.05 – 0.2) 0.12 (0.02 – 0.08) -2 -AL * 18 end cutting insert CoroMill® 790 D 16 16 16 22 22 22 H-NL H-NM H-PL H-NL H-NM H-PL 0.2 0.3 0.15 0.3 0.6 0.15 (0.1 – 0.3) (0.1 – 0.4) (0.10 – 0.20) (0.10 – 0.40) (0.20 – 0.60) (0.10 – 0.20) 0.2 0.3 0.05 0.3 0.6 0.05 (0.1 – 0.3) (0.1 – 0.4) (0.02 – 0.08) (0.10 – 0.40) (0.20 – 0.60) (0.02 – 0.08) E Drilling R790 Threading -PL2 -PL Milling Coromant finishing long edge CoroMill® Century R590 -NL CD10 0.15 (0.05 – 0.30) 0.15 (0.05 – 0.30) -NL H10 0.20 (0.10 – 0.40) 0.20 (0.10 – 0.40) 0.17 (0.1 – 0.3) 0.17 (0.1 – 0.3) R/L262.4 R/L262.42 SBEN SBEX SBEX-11 Finishing R260.90 CDE Roughing Boring AUTO-FS F Tool holding/ Machines G T-Line 0.17 (0.1 – 0.3) 0.17 (0.1 – 0.3) Materials H D 193 MTG09 Milling D182-D197.indd 193 Information/ Index I 2009-11-24 13:30:28 General turning A Parting and grooving B Milling – feed recommendations Face milling κr = 75° - 10° CoroMill® 345 C Threading CoroMill® 245 R245 Insert geometry Milling Starting value (min.- max.) 0.15 (0.07 – 0.20) 0.10 (0.07 – 0.14) Medium 0.30 (0.15 – 0.45) 0.21 (0.10 – 0.32) M-PH M-KH Heavy 0.45 0.40 (0.35 – 0.55) (0.30 – 0.50) 0.32 0.28 (0.25 – 0.39) (0.21 – 0.35) 0.14 (0.08–0.21) 0.10 (0.06 – 0.15) 0.11 (0.07–0.17) CT530, H13A, H10 0.08 (0.06 – 0.12) Light 0.17 (0.08 – 0.21) 0.12 (0.06 – 0.15) Medium 0.24 0.12 (0.10 – 0.28) (0.08 – 0.18) CT530, H13A 0.17 0.09 (0.07 – 0.20) (0.06 – 0.13) 0.23 (0.10 – 0.28) 0.16 (0.07 – 0.20) 0.35 (0.10 – 0.42) 0.25 (0.07 – 0.30) 0.24 (0.10 – 0.28) 0.17 (0.07 – 0.20) E-PL E-ML E-KL } M-PH M-KH Light Heavy E-AL E Ceramic 0.21 (0.10 – 0.30) CC6190 0.15 0.07 – 0.20 E CBN 0.14 (0.07 – 0.21) CB50 0.10 (0.06 – 0.15 E PCD 0.14 (0.07 – 0.21) CD10 0.10 (0.06 – 0.15 0.20 0.22 0.22 0.25 (0.12 – 0.28) (0.15 – 0.28) (0.12 – 0.35) (0.15 – 0.35) 0.18 0.20 0.20 0.23 (0.11 – 0.25) (0.14 – 0.25) (0.11 – 0.32) (0.14 – 0.32) 0.17 (0.08 – 0.21) 0.12 (0.06 – 0.15) 0.24 (0.1 – 0.42) 0.17 (0.07 – 0.30) 0.24 (0.1 – 0.28) 0.17 (0.07 – 0.20) 0.35 0.24 (0.1 – 0.70) (0.1 – 0.28) 0.25 0.17 (0.07 – 0.50) (0.07 – 0.20) 0.16 (0.08 – 0.21) 0.15 (0.08 – 0.20) -PL -PM -KL -KM Drilling (min.- max.) M-PM M-MM M-KM 13 K-MM CoroMill® 365 Starting value Light M-PM, M-KM M-PM, M-KM E Max. chip thickness, hex (mm) E-PL E-ML E-KL M-PL M-KL M-PL M-KL D Insert size Feed per tooth, fz (mm/tooth) 15 Boring F Sandvik AUTO Tool holding/ Machines G R/L260.3 AUTO-AF H N260.8-F N260.8-L Materials R/L260.8 R/L260.82 TNHF-WL TNEF-WL TNHF-CA TNEF-CA TNHF-65 TNEF-65 TNJN TNEN TNCN Information/ Index I D 194 MTG09 Milling D182-D197.indd 194 2009-11-24 13:30:29 κr = 75° - 10° CoroMill® 360 Insert geometry PM MM KH Feed per tooth, fz (mm/tooth) Max. chip thickness, hex (mm) Insert size Starting value (min.- max.) Starting value (min.- max.) B 19 28 0.45 (0.3 – 0.7) 0.40 (0.25 – 0.60) Parting and grooving Face and plunge milling A General turning Milling – feed recommendations T-MAX® 45 R260.7 LNCX -11 -31 -32 0.35 0.35 0.35 (0.10 – 1.0) (0.10 – 0.70) (0.10 – 0.70) 0.25 0.25 0.25 (0.07 – 0.70) (0.07 – 0.50) (0.07 – 0.50) Threading C CoroMill® 210 Milling D Face milling M-PM M-KM M-MM E-PM E-MM E-KM 1.0 1.5 (0.4 – 2.0) (0.5 – 3.0) 0.17 0.26 (0.07 – 0.35) (0.08 – 0.52) (0.01 – 0.2) (0.10 – 0.25) 0.17 0.26 (0.07 – 0.35) (0.08 – 0.52) E Plunge milling 09 14 0.15 0.20 Drilling R210 09 14 F LPMH-PM LPMH-MM 25 0.20 (0.10 – 0.30) Boring Coromant plunge cutter Tool holding/ Machines G Materials H D 195 MTG09 Milling D182-D197.indd 195 Information/ Index I 2009-11-24 13:30:30 General turning A Milling – feed recommendations Round insert and Ball Nose Parting and grooving B Max. chip thickness, hex (mm) Starting value Starting value (min.- max.) CoroMill® 200 R200 Light 10 – 20 0.08 (0.05 – 0.12) -PM -KM -MM -WM Medium 10 – 20 0.17 (0.10 – 0.20) -PH -KH -WH Heavy 10 – 20 0.25 (0.10 – 0.30) CBN 12 0.10 (0.05 – 0.15) 12 – 16 0.20 (0.07 – 0.30) 8 10 12 16 20 0.13 0.13 0.15 0.18 0.2 (0.05 – 0.15) (0.05 – 0.15) (0.05 – 0.20) (0.05 – 0.20) (0.05 – 0.25) 0.08 0.10 0.13 0.18 0.18 0.2 0.25 (0.05 – 0.12) (0.05 – 0.15) (0.05 – 0.20) (0.05 – 0.25) (0.05 – 0.25) (0.05 – 0.30) (0.05 – 0.40) 0.13 0.15 0.15 0.18 0.20 (0.07 – 0.20) (0.07 – 0.25) (0.07 – 0.25) (0.07 – 0.25) (0.07 – 0.30) 0.15 0.20 0.20 0.25 0.35 (0.07 – 0.25) (0.07 – 0.30) (0.07 – 0.30) (0.07 – 0.40) (0.07 – 0.55) 0.10 0.10 0.15 0.15 0.17 0.17 0.20 0.25 (0.08 – 0.21) (0.08 – 0.21) (0.08 – 0.25) (0.08 – 0.25) (0.08 – 0.28) (0.08 – 0.28) (0.10 – 0.42) (0.10 – 0.42) 0.10 0.10 0.10 0.15 0.15 0.17 0.17 0.20 0.20 (0.05-0.21) (0.05-0.21) (0.05-0.21) (0.05-0.25) (0.05-0.25) (0.05-0.28) (0.05-0.28) (0.05-0.35) (0.05-0.35) 0.07 0.07 0.09 0.11 0.11 0.13 0.13 0.13 (0.05-0.18) (0.05-0.18) (0.07-0.22) (0.07-0.25) (0.07-0.25) (0.07-0.29) (0.07-0.29) (0.07-0.29) Threading -PL -ML -KL Ceramic CoroMill® 300 E-PM E-MM Light R300 E-PM E-MM Medium M-PM M-MM Medium M-PH M-MH M-KH Heavy Milling Drilling E Detailed feed table, see Main catalogue. F Ball Nose Boring CoroMill® Ball Nose R216 -12 .. M-M -16 .. M-M -20 .. M-M -25 .. M-M -30 .. M-M -32 .. M-M -40 .. M-M -50 .. M-M 5 7 8 10 12 16 20 8 10 12 16 20 8 10 12 16 20 Face milling round insert (ap<iC/2) mm. fz = Tool holding/ Machines -10 .. E-M -12 .. E-M -16 .. E-M -20 .. E-M -25 .. E-M -30 .. E-M -32 .. E-M -40 .. E-M -50 .. E-M H Materials CoroMill® Ball Nose Finishing R216F I -08 .. E-L -10 .. E-L -12 .. E-L -16 .. E-L -20 .. E-L -25 .. E-L -30 .. E-L -32 .. E-L hex × iC 2 × √ ap × iC − ap² Side milling (ae<Dcap/2) and round insert (ap<iC/2) mm. fz = hex × iC × Dcap 4 × √ ap × iC × ap² × √ Dcap × ae − ae² Feed per tooth (mm/tooth), cutter centered. fz = G Information/ Index (min.- max.) Round C D Insert size, iC Insert geometry Feed per tooth, fz (mm/tooth) Dc × hex Dcap Feed per tooth (mm/tooth), side milling. D3 × hex fz = √D ² – (D cap cap – 2 × ae)² 0.12 0.12 0.15 0.17 0.17 0.20 0.20 0.20 (0.10-0.25) (0.10-0.25) (0.15-0.35) (0.15-0.35) (0.15-0.35) (0.15-0.40) (0.15-0.40) (0.15-0.40) D 196 MTG09 Milling D182-D197.indd 196 2009-11-24 13:30:42 Side and face mills Insert geometry CoroMill® 327 -GM -GMM -GC -CH -TH -THM -RM Feed per tooth, fz (mm/tooth) Max. chip thickness, hex (mm) Insert size Starting value (min. - max.) Starting value (min. - max.) 06, 09, 12, 14 0.15 (0.07 – 0.25) 0.06 (0.02 – 0.1) General turning Slot milling A B Parting and grooving Milling – feed recommendations C CoroMill® 328 -GM -GC -TH 13 (0.1 – 0.2) 0.1 (0.05 – 0.15) 0.1 (0.07 – 0.17) 0.07 (0.05 – 0.12) 0.15 08, 11, 13, 14 0.18 (0.05 – 0.22) 0.10 (0.05 – 0.15) (0.07 – 0.22) 0.12 (0.08 – 0.15) 04, 05 0.19 08, 11, 13, 14 0.25 (0.08 – 0.29) 0.13 (0.08 – 0.20) (0.1 – 0.29) 0.17 (0.10 – 0.20) -PL, ML, -KL 0.11 (0.07 – 0.17) 0.08 (0.05 – 0.12) -WM, -PM, -MM -KM 0.24 (0.10 – 0.28) 0.17 (0.10 – 0.20) -WH, -KH, -PH 0.35 (0.10 – 0.42) 0.25 (0.10 – 0.30) 0.09 0.09 0.09 (0.02 – 0.12) (0.02 – 0.12) (0.02 – 0.12) 0.06 0.08 0.08 (0.02 – 0.06) (0.02 – 0.13) (0.02 – 0.13) Threading 0.15 Seat size CoroMill® 329 D Milling -D, -E -F, -G -H, -J, -K -PL, ML, -KL, -WL, -NL N/R331.32 R331.35 R/L331.52 -PM, -MM, -KM, -WM 04, 05 RCHT/RCKT F 2–4 5–6 G Tool holding/ Machines 330.20 -AA -AA -XE H Materials 330.20 Boring For slotting I D 197 Information/ Index T-MAX® Q-Cutter E Drilling CoroMill® 331

Milling Technical Guide: Applications, Products & Recommendations

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