GATEWAY
Traditional
Machining
Department of Mechanical Engineering, The Ohio State University
Sl. #29
GATEWAY
Chip Formation (Traditional Machining)
In any traditional machining process, chips are formed by a
shearing process
Shear
Plane
Shear
Plane
Shear
Plane
Department of Mechanical Engineering, The Ohio State University
Sl. #30
Ref: Manufacturing Processes for Engineering Materials by S. Kalpakjian, Addison Wesley, 2nd Ed., 1991
GATEWAY
Chip Types
Continuous
Built Up Edge (BUE)
BUE
Segmented
Discontinuous
Department of Mechanical Engineering, The Ohio State University
Sl. #31
Ref: Manufacturing Processes for Engineering Materials Fig 8.4, p 478.
GATEWAY
Tool Geometry
The shape and orientation of the cutting tool greatly affects
the chip formation mechanics
Rake
Angle 
tc
2
to
Clearance Angle
1

3

Shear Angle
Department of Mechanical Engineering, The Ohio State University
Sl. #32
GATEWAY
Rake Angle
Of particular importance is the rake angle that the tool
makes with the workpiece normal
Positive Rake
Cutter
Velocity
Neutral Rake
Cutter
Velocity
Negative Rake
Cutter
Velocity
-
+
0
Workpiece
Normal
Workpiece
Normal
Workpiece
Normal
Department of Mechanical Engineering, The Ohio State University
Sl. #33
GATEWAY
Tool Wear
Department of Mechanical Engineering, The Ohio State University
Sl. #34
GATEWAY
Cutting Parameters (Vertical Milling)
Depth of Cut- measured along workpiece normal
Step over Distance- (also called radial depth of cut)- Measured
in tangent plane of workpiece and perpendicular to
cutter travel or workpiece feed
f
w
s is step over distance
d is depth of cut
f is feed direction of
workpiece
s
Department of Mechanical Engineering, The Ohio State University
Sl. #35
GATEWAY
Feeds/Speeds
Milling Maching Cutting Speeds- Terminology of Machine Tools(Krar, Oswald) Table 61-1
High Speed Steel Cutter
Carbide Cutter
Material
sfm
m/min
sfm
m/min
Machine Steel
70-100
21-30
150-250
45-75
Tool Steel
60-70
18-20
125-200
40-60
Cast Iron
50-80
15-25
125-200
40-60
Bronze
65-120
20-35
200-400
60-120
Aluminum
500-1000
150-300
1000-2000
300-600
Recommended Feed per Tooth High Speed Steel Cutters - Terminology of Machine Tools(Krar, Oswald) Table 61-2
Helical
Slotting &
Form
Circular
Face Mills
Mills
Side Mills
End Mills
Relieved
Saws
Material
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
Aluminum
.022
.55
.018
.45
.013
.33
.011
.28
.007
.18
.005
.13
Brass & bronze
.014
.35
.011
.28
.008
.20
.007
.18
.004
.10
.003
.08
(medium)
Cast iron
.013
.33
.010
.25
.007
.18
.007
.18
.004
.10
.003
.08
(medium)
Machine steel
.012
.30
.010
.25
.007
.18
.006
.15
.004
.10
.003
.08
Tool steel
.010
.25
.008
.20
.006
.15
.005
.13
.003
.08
.003
.08
(medium)
Stainless steel
.006
.15
.005
.13
.004
.10
.003
.08
.002
.05
.002
.05
Department of Mechanical Engineering, The Ohio State University
Sl. #36
GATEWAY
Feeds & Speeds
Recommended Feed per Tooth Cem. Carbide Tip Cutters - Terminology of Machine Tools(Krar, Oswald) Table 61-3
Helical
Slotting &
Form
Circular
Face Mills
Mills
Side Mills
End Mills
Relieved
Saws
Material
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
Aluminum
.020
.50
.016
.40
.012
.30
.010
.25
.006
.15
.005
.13
Brass & bronze
.012
.30
.010
.25
.007
.18
.006
.15
.004
.10
.003
.08
(medium)
Cast iron
.016
.40
.013
.33
.010
.25
.008
.20
.005
.13
.004
.10
(medium)
Machine steel
.016
.40
.013
.33
.009
.23
.008
.20
.005
.13
.004
.10
Tool steel
.014
.35
.011
.28
.008
.20
.007
.18
.004
.10
.004
.10
(medium)
Stainless steel
.010
.25
.008
.20
.006
.15
.005
.13
.003
.08
.003
.08
Lathe Feed & Speeds- Machine Tool Practices (Kibbe, et al)Table I-5
Low-Carbon High Carbon Alloy Steel
Aluminum
Material
Steel
Steel-anneal Normalized
Alloys
Speed (sfm)
Roughing
90
50
45
200
Finishing
120
65
60
300
Feed (ipr)
Roughing .010-.020
.010-.020
.010-.020
.015-.030
Finishing .003-.005
.003-.005
.003-.005
.005-.010
Cast Iron
Bronze
70
80
100
130
.010-.020
.003-.010
.010-.020
.003-.010
Department of Mechanical Engineering, The Ohio State University
Sl. #37
Ref: From Machinery’s Handbook 21st ed
GATEWAY
Feeds & Speeds
Cutting Speeds for Drilling (fpm)
Material
Cutting speed (fpm)
Wrought Aluminum Alloys (Cold Drawn)
300
Free Cutting Brass (Cold Drawn)
175
Wrought Magnesium Alloys (Cold Drawn)
350
Mold Steels- P20 & P21
60
1040 Plain Carbon Steel (CD ,Hardness 175-225HB)
75
"For ordinary twist drills (HSS- high speed steel) the feed rate used is...
0.001-0.003 in/rev for drills smaller than 1/8 in. (dia.);
0.002-0.006 in/rev for 1/8 to 1/4 in. dia. drills;
0.004-0.010 in/rev for 1/4 to 1/2 in. dia. drills;
0.007-0.015 in/rev for 1/2 to 1 in. dia. drills; and,
0.010-0.025 in/rev for drills larger than 1 inch. (dia)
The lower values in the feed ranges should be used for hard materials such as tool steels,
superalloys, and work hardening stainless steels; the higher values in the feed ranges
should be used to drill soft materials such as aluminum and brass."
Department of Mechanical Engineering, The Ohio State University
Sl. #38
Ref: From Machinery’s Handbook 21st ed
GATEWAY
“Optimal” Feeds & Speeds
• FW Taylor studied the effects of the feed, depth of cut, and
cutting speed:
1) Cutting Speed is the dominating factor in determining tool life
2) Feeds and Depths of Cut are the dominant forces in determining
the force acting on the tool
• In the “typical operating range”, tool life (T) and
cutting speed (V) are related according to Taylor’s
Equation
VT n  C
where n & C are experimentally determined constants
• Taylor recommended using the maximum allowable feed
and depth of cut, then selecting V to balance tool wear with
cycle time for the process
Department of Mechanical Engineering, The Ohio State University
Sl. #39
GATEWAY
Cutting Speeds
Cutting Rates- Often given speeds in SFM (surface feet/min),
but control spindle rotation in RPM (rev/min).
Formula for spindle RPM comes from basic kinematics v= x r
 v R
 in radians per minute, v in inches per minute
and R & D in inches - R  D 2 D = cutter diameter
To find  in Revolution s per minute, given V in SFM
V  ft
 
min    12 in   1 rev 

 


D (in)   1 ft   2 rad 
2


 
 D  12  sometimes approximat ed as    4 DV 
 V
Note: Use the maximum effective cutting diameter of tool
Department of Mechanical Engineering, The Ohio State University
Sl. #40
GATEWAY
Cutting Diameter
To select the correct radius (or diameter) to use in the formula-Determine what the spindle is rotating
Find the perpendicular distance from the axis of rotation to the furthest point
where cutting occurs
Double it to get the diameter
Flat Nosed End Mill
d=cutter diameter
Ball Nosed End Mill
if ball is not “buried” in
workpiece, then d will be
less than cutter diameter
i.e. NO cutting occurs at
full tool diameter
Lathe- part turns(NOT tool)
r is from center to tool
if turning down- d is
workpiece diameter
Axis of
Revolution
Axis
d
Cutting
Edge
d
d
Axis of
Revolution
Department of Mechanical Engineering, The Ohio State University
Sl. #41
Cutting
Edge
GATEWAY
Feed Rates
Feed Rates are commonly given as Advance Per Tooth (APT)
To get the feed rate in surface inches per minute use:
f  (APT)N
f is the feed rate in inches/min
 is the cutter speed rev/min
N is the number of teeth on the cutter
Feeds on lathes and drills can be in ipr (inches per revolution):
N is no longer required in formula: f  (ipr)
More properly one wishes to control the chip load or nominal
chip thickness tl. If the cutter is NOT fully loaded, one must
increase the feed (APT) to keep the same chip load (tl).
Most tabulated values of the APT assume a fully loaded cutterthey are really listings of the required chip load tl.
Department of Mechanical Engineering, The Ohio State University
Sl. #42
GATEWAY
Chip Load and Advance Per Tooth
APT
APT
tl
tl
Step over distance (radial
depth of cut) at least
1/2 tool diameter
chip load (t )= APT
Step over distance (radial
depth of cut) less than
1/2 tool diameter
chip load (t ) < APT
l
Department
of Mechanical Engineering, The Ohio Statel University
Sl. #43
GATEWAY
Shallow Cuts with Ball Nosed End Mill
Decrease in Effective
Cutting Diameter
Decrease in
Chip Load
APT
Rnom
Rnom
t
d
l
Rcut
Rcut 
2
2
Rnom
  Rnom  d 
Notice how the chip load
(tl) is less than the APT
for a shallow cut
Department of Mechanical Engineering, The Ohio State University
Sl. #44
GATEWAY
RCTF- Ball Nose @ Small Depth of Cut
Nominal Tool Diameter
0.375
0.5
0.625
0.75
1
1.25
1.5
2
2.5
3
Dia. (Effective Diameter at DOC) / RCTF (Radial Chip Thinning Factor)
DOC
0.063
0.125
0.188
0.250
0.313
0.375
0.438
0.500
0.563
0.625
0.688
0.750
0.813
0.875
0.938
1.000
1.250
1.500
Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF
0.28 0.7 0.33 0.7 0.38 0.6 0.41 0.5 0.48 0.5 0.54 0.4 0.60 0.4 0.70 0.3 0.78 0.3 0.86 0.3
0.35 0.9 0.43 0.9 0.50 0.8 0.56 0.7 0.66 0.6 0.75 0.5 0.83 0.4 0.97 0.4 1.09 0.4 1.20 0.4
0.38 1.0 0.48 0.97 0.57 0.9 0.65 0.9 0.78 0.8 0.89 0.7 0.99 0.6 1.17 0.6 1.32 0.5 1.45 0.5
0.50 1.0 0.61 0.98 0.71 0.95 0.87 0.9 1.00 0.8 1.12 0.7 1.32 0.7 1.50 0.6 1.66 0.6
0.63 1.0 0.74 1.0 0.93 0.95 1.08 0.9 1.22 0.7 1.45 0.7 1.65 0.7 1.83 0.6
0.75 1.0 0.97 0.95 1.15 0.95 1.30 0.8 1.56 0.8 1.79 0.7 1.98 0.7
0.99 1.0 1.19 0.95 1.36 0.8 1.65 0.8 1.90 0.8 2.12 0.7
1.00 1.0 1.22 0.95 1.41 0.9 1.73 0.8 2.00 0.8 2.24 0.7
1.24 1.0 1.45 0.9 1.80 0.9 2.09 0.8 2.34 0.8
1.25 1.0 1.48 0.95 1.85 0.9 2.17 0.9 2.44 0.8
1.49 0.95 1.90 0.95 2.23 0.9 2.52 0.8
1.50 1.0 1.94 0.95 2.29 0.9 2.60 0.9
1.96 0.95 2.34 0.9 2.67 0.9
1.98 0.95 2.38 0.95 2.73 0.9
2.00 1.0 2.42 0.95 2.78 0.9
2.00 1.0 2.45 0.95 2.83 0.9
2.50 1.0 2.96 0.95
3.00 1.0
Department of Mechanical Engineering, The Ohio State University
Sl. #45
Ref: Figure O-51, Kibbe, et al. Machine Tool Practices 5th Ed, Prentice Hall,1995.
GATEWAY
RCTF- Peripheral Milling w/ Flat Nose
.05
.06
.08
.10
.12
.14
.16
.18
.20
.25
.5
.4
.3
.8
.7
.6
.9
1.0
.95
Department of Mechanical Engineering, The Ohio State University
Sl. #46
Ref: Figure O-49, Kibbe, et al. Machine Tool Practices 5th Ed, Prentice Hall,1995.
GATEWAY
Feeds w/ Radial Chip Thinning Factor
Proper feeds come from finding the required advance per tooth (APT) to get
correct chip load (feed value commonly given in books)
let APT 






t
l




CTF 
R
RCTF  Radial Chip Thinnin g Factor
f  ( APT ) N 
As we use it, the RCTF is a “first pass” improvement
1) RCTFs for FLAT end mill with small step over distance
2) RCTFs for BALL end mill with small depth of cut
3) Anything over tool radius is assumed to be fully loaded
In some cases tables incorporate RCTFs and give true APT
But usually what you look up in a table is really tl
Department of Mechanical Engineering, The Ohio State University
Sl. #47
GATEWAY
Feeds/Speeds
F
Milling Maching Cutting Speeds- Terminology of Machine Tools(Krar, Oswald) Table 61-1
High Speed Steel Cutter
Carbide Cutter
Material
sfm
m/min
sfm
m/min
Machine Steel
70-100
21-30
150-250
45-75
Tool Steel
60-70
18-20
125-200
40-60
Cast Iron
50-80
15-25
125-200
40-60
Bronze
65-120
20-35
200-400
60-120
Aluminum
500-1000
150-300
1000-2000
300-600
Recommended Feed per Tooth High Speed Steel Cutters - Terminology of Machine Tools(Krar, Oswald) Table 61-2
Helical
Slotting &
Form
Circular
Face Mills
Mills
Side Mills
End Mills
Relieved
Saws
Material
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
Aluminum
.022
.55
.018
.45
.013
.33
.011
.28
.007
.18
.005
.13
Brass & bronze
.014
.35
.011
.28
.008
.20
.007
.18
.004
.10
.003
.08
(medium)
Cast iron
.013
.33
.010
.25
.007
.18
.007
.18
.004
.10
.003
.08
(medium)
Machine steel
.012
.30
.010
.25
.007
.18
.006
.15
.004
.10
.003
.08
Tool steel
.010
.25
.008
.20
.006
.15
.005
.13
.003
.08
.003
.08
(medium)
Stainless steel
.006
.15
.005
.13
.004
.10
.003
.08
.002
.05
.002
.05
Department of Mechanical Engineering, The Ohio State University
Sl. #48
GATEWAY
Feeds & Speeds - Example 1
Estimate the cutting speed and feed rate required for a 3/4”
diameter 2 flute HSS end mill in Cast Iron, with a depth of cut
of 0.375” and a step over distance of 0.375.”
The spindle rotational speed is given by:
 V D12  50 0.7512  250 RPM
The machine feed rate is given by:
f  (APT )N  2500.00721.75 ipm
Department of Mechanical Engineering, The Ohio State University
Sl. #49
GATEWAY
Feeds & Speeds - Example 2
Estimate the depth of cut, the cutting speed, and feed rate
required when rough turning a bronze shaft, from a diameter of
2.000” to 1.800.”
Depth of cut 1 2*(DO  Di )
1 2*(2.000 1.800) 0.100"
Refer to tables to get recommended speed and feed.
Department of Mechanical Engineering, The Ohio State University
Sl. #50
GATEWAY
Feeds/Speeds for Example 2
F
F
Lathe Feed & Speeds- Machine Tool Practices (Kibbe, et al)Table I-5
Low-Carbon High Carbon Alloy Steel
Aluminum
Material
Steel
Steel-anneal Normalized
Alloys
Speed (sfm)
Roughing
90
50
45
200
Finishing
120
65
60
300
Feed (ipr)
Roughing .010-.020
.010-.020
.010-.020
.015-.030
Finishing .003-.005
.003-.005
.003-.005
.005-.010
Cast Iron
Bronze
70
80
100
130
.010-.020
.003-.010
.010-.020
.003-.010
Department of Mechanical Engineering, The Ohio State University
Sl. #51
GATEWAY
Feeds & Speeds - Example 2 (Cont’d)
Estimate the depth of cut, the cutting speed, and feed rate
required when rough turning a bronze shaft, from a diameter of
2.000” to 1.800.”
Depth of cut 1 2*(DO  Di )
1 2*(2.000 1.800) 0.100"
Recommended rates- cutting=100 sfm, feed=0.010 ipr
The recommended speed is
V
 
 12
D

 10012 
190
 
 

 2


RPM
The recommended feed is
f  (APT )190*(0.010)1.9 ipm
Department of Mechanical Engineering, The Ohio State University
Sl. #52
GATEWAY
Feeds & Speeds - Example 3
Estimate the cutting speed and feed rate required for a 1/2”
diameter HSS 2 flute ball nose end mill in “medium” tool steel,
with a depth of cut of 0.0625” and a step over distance of 0.250.”
The ball end mill depth of cut is less than the radius. Therefore
the effective diameter must be computed:
2  R
D 2* Rnom
 nom d 
2
2
0.5002 0.500
2


 0.0625

  

 2 
 2

 0.33 in
Find speeds and feeds from table.
Department of Mechanical Engineering, The Ohio State University
Sl. #53
GATEWAY
Feeds/Speeds for Example 3
F
Milling Maching Cutting Speeds- Terminology of Machine Tools(Krar, Oswald) Table 61-1
High Speed Steel Cutter
Carbide Cutter
Material
sfm
m/min
sfm
m/min
Machine Steel
70-100
21-30
150-250
45-75
Tool Steel
60-70
18-20
125-200
40-60
Cast Iron
50-80
15-25
125-200
40-60
Bronze
65-120
20-35
200-400
60-120
Aluminum
500-1000
150-300
1000-2000
300-600
Recommended Feed per Tooth High Speed Steel Cutters - Terminology of Machine Tools(Krar, Oswald) Table 61-2
Helical
Slotting &
Form
Circular
Face Mills
Mills
Side Mills
End Mills
Relieved
Saws
Material
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
in.
mm
Aluminum
.022
.55
.018
.45
.013
.33
.011
.28
.007
.18
.005
.13
Brass & bronze
.014
.35
.011
.28
.008
.20
.007
.18
.004
.10
.003
.08
(medium)
Cast iron
.013
.33
.010
.25
.007
.18
.007
.18
.004
.10
.003
.08
(medium)
Machine steel
.012
.30
.010
.25
.007
.18
.006
.15
.004
.10
.003
.08
Tool steel
.010
.25
.008
.20
.006
.15
.005
.13
.003
.08
.003
.08
(medium)
Stainless steel
.006
.15
.005
.13
.004
.10
.003
.08
.002
.05
.002
.05
Department of Mechanical Engineering, The Ohio State University
Sl. #54
GATEWAY
Feeds & Speeds - Example 3 (Cont’d)
Estimate the cutting speed and feed rate required for a 1/2”
diameter HSS 2 flute ball nose end mill in “medium” tool steel,
with a depth of cut of 0.0625” and a step over distance of 0.250.”
D 0.33 in
V  60 sfm and APT =0.005 in
The recommended speed is:
V
 
 
 12
D 

 12
 60
 
 
  0.33 


 690

RPM
Find the chip reduction factor from table.
Department of Mechanical Engineering, The Ohio State University
Sl. #55
GATEWAY
RCTF- Ball Nose @ Small Depth of Cut for Ex 3
Nominal Tool Diameter
0.375
0.5
0.625
0.75
1
1.25
1.5
2
2.5
3
Dia. (Effective Diameter at DOC) / RCTF (Radial Chip Thinning Factor)
DOC
0.063
0.125
0.188
0.250
0.313
0.375
0.438
0.500
0.563
0.625
0.688
0.750
0.813
0.875
0.938
1.000
1.250
1.500
Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF Dia. RCTF
0.28 0.7 0.33 0.7 0.38 0.6 0.41 0.5 0.48 0.5 0.54 0.4 0.60 0.4 0.70 0.3 0.78 0.3 0.86 0.3
0.35 0.9 0.43 0.9 0.50 0.8 0.56 0.7 0.66 0.6 0.75 0.5 0.83 0.4 0.97 0.4 1.09 0.4 1.20 0.4
0.38 1.0 0.48 0.97 0.57 0.9 0.65 0.9 0.78 0.8 0.89 0.7 0.99 0.6 1.17 0.6 1.32 0.5 1.45 0.5
0.50 1.0 0.61 0.98 0.71 0.95 0.87 0.9 1.00 0.8 1.12 0.7 1.32 0.7 1.50 0.6 1.66 0.6
0.63 1.0 0.74 1.0 0.93 0.95 1.08 0.9 1.22 0.7 1.45 0.7 1.65 0.7 1.83 0.6
0.75 1.0 0.97 0.95 1.15 0.95 1.30 0.8 1.56 0.8 1.79 0.7 1.98 0.7
0.99 1.0 1.19 0.95 1.36 0.8 1.65 0.8 1.90 0.8 2.12 0.7
1.00 1.0 1.22 0.95 1.41 0.9 1.73 0.8 2.00 0.8 2.24 0.7
1.24 1.0 1.45 0.9 1.80 0.9 2.09 0.8 2.34 0.8
1.25 1.0 1.48 0.95 1.85 0.9 2.17 0.9 2.44 0.8
1.49 0.95 1.90 0.95 2.23 0.9 2.52 0.8
1.50 1.0 1.94 0.95 2.29 0.9 2.60 0.9
1.96 0.95 2.34 0.9 2.67 0.9
1.98 0.95 2.38 0.95 2.73 0.9
2.00 1.0 2.42 0.95 2.78 0.9
2.00 1.0 2.45 0.95 2.83 0.9
2.50 1.0 2.96 0.95
3.00 1.0
Department of Mechanical Engineering, The Ohio State University
Sl. #56
Ref: Figure O-51, Kibbe, et al. Machine Tool Practices 5th Ed, Prentice Hall,1995.
GATEWAY
Feeds & Speeds - Example 3 (Cont’d)
Estimate the cutting speed and feed rate required for a 1/2”
diameter HSS 2 flute ball nose end mill in “medium” tool steel,
with a depth of cut of 0.0625” and a step over distance of 0.250.”
D 0.33 in
V  60 sfm and APT =0.005 in
 690 RPM
Look up tables give RCTF =0.7
The recommended feed rate is:
f  (APT ) N  690 0.0050.729.9 ipm
Department of Mechanical Engineering, The Ohio State University
Sl. #57
GATEWAY
Machinability
Machinability generally involves three factors
1) Surface Finish
2) Tool Life
3) Force and Power Requirements
Machinability Ratings are the cutting speeds required to obtain
a tool life of T=60 min-- (in general, for a given material,
higher speeds decrease the tool life, & slower speeds increase it
Standard is AISI 1112 steel- rating of 100
for a tool life of 60 min, use cutting speed of 100 SFM (AISI 1112)
Machinability of Various Materials
Free Cutting Brass
2011 wrought Al
Nickel
AISI 1112 Steel
300
200
200
100
Pearlitic Gray Iron
3140 steel
Inconel
Precip-Harden'g Steel
70
55
30
20
Department of Mechanical Engineering, The Ohio State University
Sl. #58
From example 8.5, Kalpakjian. Manufacturing Processes for Engineering Materials 2nd Ed, Addison-Wesley 1991.
GATEWAY
Power & Force Estimation
Power, P, requirements can then be determined as...
P  u  MRR
where MRR is the Material Removal Rate
Torque, , is found from P   where  is the spindle speed
u  MRR


Fp, the force in the direction of the cutting velocity, V, is
Fp 
P u MRR

V
V
Department of Mechanical Engineering, The Ohio State University
Sl. #59
GATEWAY
Specific Energies of Machining
  0.010 in 



u can be determined from u  uo 1 
o 
 100  tl

0.2
where  is the effective rake angle (in degrees) &
tl is the undeformed (nominal) chip thickness (in inches)
Material
 lbf  in 
uo 
3 
 in 
Aluminum Alloys
100,000
Gray Cast Iron
Free Machining Brass
Free Machining Steel (AISI 1213)
“Mild” Steel (AISI 1018)
Titanium Alloys
Stainless Steels
High Temp. Alloys
150,000
150,000
250,000
300,000
500,000
700,000
700,000
Department of Mechanical Engineering, The Ohio State University
Sl. #60
Ref: Shaw. Metal Cutting Principles, Clarendon Press 1984, p. 43
GATEWAY
Cutting Power - Example 1
Find the power for an 8” HSS face mill (10 teeth, e=30o) to
remove 0.1” from Cold Drawn, Wrought Aluminum, with a step
over distance of 4.0” at a speed of 600 fpm and an APT 0.022.”
Compute the speed and feed.
V 12  600 12 
         290 RPM
D   8  
f  ( APT )N  290(0.022 )(10 )  64
in
min
The material removal rate is:
 in 3 
MRR  f  w d  64  0.1 4  25.6 

min 
Department of Mechanical Engineering, The Ohio State University
Sl. #61
GATEWAY
Cutting Power - Example 1(cont’d)
Find the power for an 8” HSS face mill (10 teeth, e=30o) to
remove 0.1” from Cold Drawn, Wrought Aluminum, with a step
over distance of 4.0” at a speed of 600 fpm and an APT 0.022.”
  290 RPM
in
f  64
min
in3
MRR  25.6
min
t1  APT  0.022 in
lb in
u0  105 f 3
in
0.2

0.010 in 


u  u0 1 

 100Þ
 t1 
lb f in  30Þ0.010 in 0.2  1 hp  min 
5

 
 10
1

3 



in
100Þ
0.22  395950lb f in 
Power at spindle  PS  u  MRR  0.15125.6  3.86 hp
Department of Mechanical Engineering, The Ohio State University
Sl. #62
0.2

 0.010 in 

u  u0 1 

 100  t1 
GATEWAY
Cutting Power - Example 2
Estimate the work required to turn down an annealed 304
stainless rod 6 in long from a diameter of 0.500” to a
diameter of 0.480.” (Assume e=13o, & ipr=0.003”)
lb f in
& t1  ipr  0.003"
in3
0.2

0.010 in 


u  u0 1 

 100Þ
 t1 
13Þ 0.010 in 0.2
5 lb f in 
3 lb f in




 7 *10
1

775
*10
in 3  100Þ 0.003 
in 3
u0  7 *105

do2  di2 ( L )

4

 (0.5 )2  (0.480 )2 (6 )  0.092 in3
4
Volume Re moved  V 

lb in 
E  u V  775 *10 3 f 3 0.092 in3   71,300 lb f in
in 

Department of Mechanical Engineering, The Ohio State University
Sl. #63
GATEWAY
Summary
Factors for Chip production:
• rake angle
• clearance angle
• shear angle
Factors that affect machining parameters:
• effective diameter
• depth of cut
• radial depth of cut (if applicable)
• speeds (tip and spindle)
• feed rate
• material
• tool material
Department of Mechanical Engineering, The Ohio State University
Sl. #64
GATEWAY
Credits

This module is intended as a supplement to design classes in mechanical
engineering. It was developed at The Ohio State University under the NSF
sponsored Gateway Coalition (grant EEC-9109794). Contributing members
include:

Gary Kinzel …………………………………….. Project supervisor
Chris Hubert and Alan Bonifas ..……………... Primary authors
Phuong Pham and Matt Detrick ……….…….. Module revisions
L. Pham …………………………………….….. Audio voice



References:
Machinery’s Handbook 21st ed
Kalpakjian, S. and Addison Wesley, Manufacturing Processes for Engineering Materials , 2nd
Ed., 1991
Kibbe, et al. Machine Tool Practices 5th Ed, Prentice Hall,1995
Shaw. Metal Cutting Principles, Clarendon Press
Department of Mechanical Engineering, The Ohio State University
Sl. #65
GATEWAY
Disclaimer
This information is provided “as is” for general educational purposes; it can
change over time and should be interpreted with regards to this particular
circumstance. While much effort is made to provide complete information,
Ohio State University and Gateway do not guarantee the accuracy and
reliability of any information contained or displayed in the presentation. We
disclaim any warranty, expressed or implied, including the warranties of fitness
for a particular purpose. We do not assume any legal liability or responsibility
for the accuracy, completeness, reliability, timeliness or usefulness of any
information, or processes disclosed. Nor will Ohio State University or
Gateway be held liable for any improper or incorrect use of the information
described and/or contain herein and assumes no responsibility for anyone’s use
of the information. Reference to any specific commercial product, process, or
service by trade name, trademark, manufacture, or otherwise does not
necessarily constitute or imply its endorsement.
Department of Mechanical Engineering, The Ohio State University
Sl. #66