Mechanical Workshop Module
Nanang Ali Sutisna
Mechanical Workshop
Module
Sutisna
Production Process Lab
President University
Nanang Ali Sutisna
Mechanical Workshop
Module
Production Process Lab
President University
Mechanical Workshop
Module
Nanang Ali Sutisna
Production Process Laboratory
Mechanical EngineeringPresident University
2020
Preface
This module is intended to be used by first year Mechanical
Engineering students as a guideline to do their laboratory tasks at
mechanical workshop in President University.
The module will help the
student in using machines and equipment available in the workshop to
achieve the learning objectives, such as lathe, drilling and milling machines.
The module also provide the standard work preparation sheet for
student and evaluation sheet for instructor.
At last, the author hopes that this module will benefit everyone who
learn how to do mechanical workshop for the first time.
10 December 2019
i
Table Of Content
Preface ...............................................................................................................................i
Table Of Content ............................................................................................................... ii
List Of Table ..................................................................................................................... iv
List Of Figure .....................................................................................................................v
General Objectives ........................................................................................................... 1
Introduction ....................................................................................................................... 2
Manufacturing Process.................................................................................................. 2
Processing Operation .................................................................................................... 2
Material modifying process: ....................................................................................... 2
Shape modifying: ....................................................................................................... 2
Material Retention: ..................................................................................................... 3
Joining process: ......................................................................................................... 3
Fundamental of Machining ............................................................................................ 4
Production Process Practice ......................................................................................... 5
Module 1 - Bench Work ...................................................................................................... 6
Specific Objectives ........................................................................................................ 7
Manual Process ............................................................................................................ 8
Engineer Files ............................................................................................................... 8
The Hacksaw ................................................................................................................ 9
Drilling ......................................................................................................................... 10
Drilling Machine Components .................................................................................. 10
Tool holding ............................................................................................................. 13
Clamping ................................................................................................................. 14
Cutting tools on drilling machines ............................................................................ 14
Twist drill.................................................................................................................. 14
Machine reamer ....................................................................................................... 15
Countersink ............................................................................................................. 15
Counterbore............................................................................................................. 15
Benchwork Exercise .................................................................................................... 16
Safety Guidelines .................................................................................................... 16
Material and Tools ................................................................................................... 16
Operation Steps: ...................................................................................................... 17
Evaluation Sheet...................................................................................................... 23
Module 2 Milling .............................................................................................................. 24
ii
Specific Objectives ...................................................................................................... 25
Fundamental of Milling ............................................................................................. 26
Milling Machine Function ......................................................................................... 26
Types of Milling Machine ......................................................................................... 26
Components of Milling Machine ............................................................................... 27
Calculation of feed and spindle speed ..................................................................... 30
Milling Exercise ........................................................................................................... 34
Safety Guidelines .................................................................................................... 34
Material, Machine and Tools .................................................................................... 34
Operation Steps: ...................................................................................................... 35
2.
Facing............................................................................................................... 35
3.
Pocketing .......................................................................................................... 35
4.
Cleaning and oiling ........................................................................................... 36
Evaluation Sheet...................................................................................................... 41
Module 3 Turning ............................................................................................................ 42
Specific Objectives ...................................................................................................... 43
Fundamental of Lathe ................................................................................................. 44
Lathe Function ............................................................................................................ 44
Calculation of feed and spindle speed ......................................................................... 49
Cutting Speed .......................................................................................................... 49
Spindle Speed ......................................................................................................... 49
Feed (f) .................................................................................................................... 51
Turning Exercise ......................................................................................................... 52
Safety Guidelines .................................................................................................... 52
Material, Machine and Tools .................................................................................... 52
Operation Steps: ...................................................................................................... 53
Evaluation Sheet...................................................................................................... 59
Module 4 Welding ........................................................................................................... 60
Specific Objectives ...................................................................................................... 61
Fundamental of Welding ............................................................................................. 62
Shielded Metal Arc Welding Exercise .......................................................................... 68
Safety Guidelines..................................................................................................... 68
Material, Machine and Tools .................................................................................... 68
Operation Steps: ...................................................................................................... 68
Evaluation Sheet...................................................................................................... 70
iii
List Of Table
Table 1 Selection of hacksaw blades .............................................................................. 10
Table 2 Cutting speed (Vc) for selected materials and cutting tools ................................ 31
Table 3 Milling Feed & Cutting speed ............................................................................ 32
Table 4 Cutting speed (Vc) for selected materials and cutting tools ................................ 50
iv
List Of Figure
Figure 1 Components of file .............................................................................................. 8
Figure 2 Types of files....................................................................................................... 9
Figure 3 Components of hacksaw ..................................................................................... 9
Figure 4 Drilling Machine ................................................................................................ 11
Figure 5 Components of drilling machine ........................................................................ 12
Figure 6 Tool holding device ........................................................................................... 13
Figure 7 Clamping device ............................................................................................... 14
Figure 8 Countersink tool(left) and Counterbore tool (right)............................................. 15
Figure 9 Verticall Milling Machine (left) and Horizontal Milling Machine (right).................. 26
Figure 10 Vertical Milling Machine components ......................................................... 28
Figure 11 Horizontal Milling Machine components ..................................................... 29
Figure 12 Types of welding ............................................................................................. 62
Figure 13 Oxyfuel gas welding ........................................................................................ 63
Figure 14 Gas Tungsten Arc welding ............................................................................. 63
Figure 15 Shielded Metal Arc Welding ........................................................................... 65
Figure 16 Sub Merged Arc Welding ............................................................................... 66
Figure 17 Gas Mertal Arc Welding ................................................................................. 66
Figure 18 Flux cored Arc welding ................................................................................... 67
Figure 19 Butt join welding ............................................................................................. 69
Figure 20 T join welding ................................................................................................. 69
v
General Objectives
The general objectives of Mechanical Workshop Practice:
1. Understand various manufacturing process in mechanical workshop,
such as manual process, machining process, and welding process.
2. Know and practice workshop safety related to manual process,
machining process and welding.
3. Differentiate different types of hand tools and be able to use the hand
tools for producing a simple part
4. Know the function of milling machine and use the machine to produce
a simple part
5. Know the function of lathe machine and use the machine to produce a
simple part
6. Know arc welding process and use it to join a given parts
1
Introduction
Manufacturing Process
Manufacturing is derived from the Latin word manufactus, means made
by hand. Now, manufacturing means making products from raw material by
using various processes, either use of hand tools, machinery or even
computers.
Production process is sequence of process for converting raw
materials or semi-finished products into finished products.
The activities of altering raw material into finished goods with
application of different types of tools, equipment, machine tools,
manufacturing set up and processes, is known as production
Processing Operation
Processing operation means the use of energy to alter workpiece
shape, properties, or appearance in order to add value to the materials.
There several processing operations as follows:
Material modifying process:
Property modifying:
 heat treatment
 surface treatment
Shape modifying:
 Material removal: removing excess material from the work piece, this
includes machining operation such as milling, drilling, and turning.
Other process in this category is grinding and non conventional
2
machining such as EDM, Laser, Electron Beam, and Electrochemical.
 Material Addition: the process of adding layer by layer of material to
form 3D object, The term additive manufacturing includes 3D printing,
rapid prototyping, direct digital manufacturing (DDM).
Material Retention:
 Deformation process: apply force exceeding yield strength to shape the
work piece: e.g. forging and extrusion
 Apply heat or mechanical force to change the geometry of work
materials: e.g. casting, molding, and powder metallurgy involving
pressing and sintering.
Joining process:
 Permanent Join: the join can not open or separated without causing
any damage, e,g welding, bonding
 Non-permanent join: the join can open or separated without causing
any damage, e,g bolted, key, pin join
 Semi permanent join: the join can open or separated with a marginal
damage to any one of the joined element, such as riveted join.
3
Fundamental of Machining
Production process by means of material removal can be done either
by hand or by machine. Machining process is classified into conventional
machining, non-conventional/advanced machining and finishing as describe
in below picture. We will discuss milling, turning, and drilling process in this
module.
4
Production Process Practice
This module is designed as a student manual of production process
exercises involving manual operation using hand tools, machining
operation, welding, and measurement as follows:
1. Bench Work: Use of marking tools,
file, hack saw, and drilling
machine
2. Milling Machine
3. Lathe Machine
4. Arc Welding
5. Basic Workshop Measurement
The exercises will produce a stationary desk assembly as in below
picture. Additional exercise is a basic joining parts using arc welding
operation.
5
Module 1 - Bench Work
TOPICS
Filing, Hand sawing,
Drilling, Counterboring
6
Specific Objectives
After you have studied this course and completed all the
exercises you will be able to:
1. Identify work safety aspects on working with hand tools
and drilling machine, including the safety for tools and
machine
2. Create marking to indicate the work piece outline or the
position of holes, slot etc. using the right tools and
measurement device
3. Use the correct hand files to shape the work piece
according to the required design, with the right way and
attitude
4. Use the hacksaw to cut excess material of the work piece,
with the right way and attitude
5. Use drilling machine to create holes and counter bore on
work piece according to design, with the right way and
attitude
7
Manual Process
Hand tools are used to remove small amounts of material, usually from
small areas of the workpiece. This may be done because no machine is
available, the workpiece is too large to go on a machine, the shape is too
intricate or simply that it would be too expensive to set up a machine to do
the work.
Engineer Files
Files are used to perform a wide variety of tasks, from simple removal
of sharp edges to producing intricate shapes where the use of a machine is
impracticable. They can be obtained in a variety of shapes and in lengths
from 150 mm to 350 mm. When a file has a single series of teeth cut across
its face it is known as single-cut file, and with two sets of teeth cut across its
face it is known as double-cut file.
Figure 1 Components of file
Always use a properly fitted handle of the correct size – on no account
should a file be used without a handle or with a handle which is split;
one slip and the tang could pierce your hand.
Files are identified either by their general shape – i.e. hand, flat or pillar – or
by their cross-section – i.e. square, three-square, round, half- round or knife.
8
Figure 2 Types of files
The Hacksaw
The hacksaw is used to cut metal. Where large amounts of waste
metal have to be removed, this is more easily done by hacksawing away the
surplus rather than by filing. If the workpiece is left slightly too large, a file
can then be used to obtain the final size and surface.
Figure 3 Components of hacksaw
The hacksaw blade fits into a hacksaw frame on two holding pins, one
of which is adjustable in order to tension the blade. The hacksaw frame
should be rigid, hold the blade in correct alignment, tension the blade easily
and have a comfortable grip.
9
Table 1 gives recommendations for the number of teeth per 25 mm on
blades used for hard and soft materials of varying thickness.
Table 1 Selection of hacksaw blades
Account should a file be used without a handle or with a handle
which is split; one slip and the tang could pierce your hand.
Drilling
The majority of drilling work is carried out on pillar drilling machines, so
called because the machine elements are arranged on a vertical pillar. The
machines in the heavy-duty range have power feed, are driven from the
motor through a gearbox, and have a drilling capacity in steel up to 50 mm
diameter. Smaller sensitive machines, (see below Figure) have a hand feed,
giving the sensitivity, are belt driven from the motor through pulleys, and
have a maximum drilling capacity in steel ranging from 5 mm up to 25 mm
diameter. These machines may be bench- or floor-mounted.
Drilling Machine Components
1. Base – provides a solid foundation for the machine, into which the
pillar is securely clamped.
2. Pillar – provides a solid support for the drill head and worktable.
3. Worktable – provides a flat surface in correct alignment with the
drill spindle upon which the workpiece can be positioned. Tee slots
10
are provided for clamping purposes. The worktable can be raised,
lowered and swung about the pillar and be securely clamped in the
required position.
4. Motor – provides the drive to the spindle through a five-step pulley
system and a twospeed gearbox, Fig. 8.2. Thus five pulley speeds
with A and B in mesh and five with C and D in mesh give a range
of 10 spindle speeds from 80 to 4000 rev/min.
Figure 4 Drilling Machine
11
5. Handwheel – provides feed to the drill by means of a rack and
pinion on the quill.
6. Quill – this is the housing inside which the spindle rotates. Only
the longitudinal movement is transmitted by the quill, which itself
does not rotate.
7. Spindle – provides the means of locating, holding and driving the
cutting tools and obtains its drive through the pulley.
8. Depth stop – provides a means of drilling a number of holes to a
constant depth.
9. Sop/start – the machine shown is switched on by a shrouded
push- button starter with a cover plate which can be padlocked to
prevent unauthorised access. A mushroom-headed stop button is
situated on the starter, and the machine can also be switched off
using the emergency kick-stop switch at the front of the base. A
safety switch is also incorporated under the belt guard and
automatically stops the spindle should the guard be lifted while the
machine is running.
10. Drill guard – provided to protect the operator from contact with
the revolving chuck and drill while still retaining visibility of the
operation. These guards range from simple acrylic shields to a
fully telescopic metal construction with acrylic windows.
Figure 5 Components of drilling machine
12
Tool holding
Drills and similar tools with parallel shanks are held in a drill chuck,
Many different typesof chuck are available, each being adjustable over its
complete range, and give good gripping power. By rotating the outer sleeve,
the jaws can be opened and closed. To ensure maximum grip, the chuck
should be tightened using the correct size of chuck key. This prevents the
drill from spinning during use and chewing up the drill shank.
A hazard in the use of chucks is the possibility of leaving a chuck key in
position. When the machine is then switched on, the chuck key can fly in
any direction and cause serious injury. When you remove a drill from the
chuck, always remember to remove the chuck key. Never leave it in the
chuck for even the shortest time.
Figure 6 Tool holding device
13
Clamping
Work is held on a drilling machine by clamping to the worktable, in a
vice or, in the case of production work, in a jig. It is sufficient to say here that
work held in a jig will be accurately drilled more quickly than by the other
methods, but large quantities of the workpiece must be required to justify
the additional cost of the equipment.
Figure 7 Clamping device
Cutting tools on drilling machines
Various cutting tools besides twist drills are used on a drilling machine,
and some of them are described below.
Twist drill
Twist drills are available with parallel shanks up to 16 mm diameter and
with taper shanks up to 100 mm diameter and are made from high- speed
steel. Standard lengths are known as jobber-series twist drills, short drills
are known as stub series, and long drills as long series and extra long
series. Different helix angles are available for drilling a range of materials,
14
Machine reamer
A reamer is used to produce a hole of greater accuracy than can be
obtained using a drill. The hole is drilled undersize by an amount depending
upon the diameter; the required finished size is then obtained with the
reamer.
Countersink
Countersink cutters are used to cut a large chamfer of the correct
angle, usually 90°, as a seating for countersink-head screws. Countersinks
should be run at a fairly slow speed to avoid chatter. They are available with
parallel and taper shanks
Figure 8 Countersink tool(left) and Counterbore tool (right)
Counterbore
A counterbore cutter is used to enlarge an existing hole to provide a flat
and square seating for a screw, bolt or nut under the workpiece surface. A
pilot is provided which locates in the existing hole and guides the tool during
cutting. These pilots may be a solid part of the tool or detachable when the
cutter is used on a series of different-size holes.
15
Benchwork Exercise
Safety Guidelines
1. Use safety protection device such as safety glasses, gloves, safety
shoes, etc.
2. Do not use surface plate measurement table for placing sharp and
heavy tools other than measurement tools.
3. Get used to place hand tools and measurement tools at safe place
and do not place on top of each other.
4. Use the tool according to its function.
Material and Tools
1. Aluminum 5083 plate, size 67x80x17 mm
2. Marking tools:
a. Scriber
b. Divider
c. Steel square
d. Drift punch
e. Hammer
3. Measurement tools:
a. Steel ruler
b. Vernier Caliper 4.
4.
Hand tools:
a. 12” flat bastard hand file
b. 10” flat smooth hand file
c. Hack saw
5.
Drilling and Counter boring:
a. Drill bit Ǿ8 mm
b. Drill bit Ǿ10 mm
c. Counter bore Ǿ 12 mm
Drilling machine
Coolant
Brush
6.
7.
8.
16
Operation Steps:
1. Prepare Datum side
a. Place the work piece on table vise
b. Do flat filing on datum A side
c. Do flat filing on datum B side, perpendicular to side A. Use steel
square to measure perpendicularity of both side.
2. Marking
a. Mark the outline using scriber, steel ruler, and steel square
b. Mark the hole positions as shown in the below picture, using
scriber, steel ruler, and steel square.
c. Mark the hole centre using drift punch, use light pressure on
hammer
d. Mark the round corner using divider
e. Mark the chamfer corner using scriber and ruler
17
3. Flat filing the other two sides
a. Do flat filing on the side parallel to side A, and perpendicular to
side B.
b. Do flat filing on the other side parallel to side B, and
perpendicular to side A. Use steel square to measure
perpendicularity of both side.
4. Cutting and filing the corners
a. Use the hacksaw to cut the chamfered corners and round
corners
b. Do flat filing on the chamfered corner
c. Do round filing on the other two corners.
5. Drilling holes
a. Place the work piece on drilling vise and secure it with
appropriate tightening
b. Position the work piece so that the drill bit is on the hole centre
position.
c. Drill all holes with 8mm drill bit, follow the depth according to
drawing
d. Drill two holes with 10 mm drill bit, follow the depth according to
drawing
e. Use coolant as necessary on each drilling operation
f. After completed, remove the work piece from the vise.
6. Cleaning and oiling
a. Clean the machine from chip and excess coolant
b. Apply oil on machine surface to prevent rust.
c. Clean the surrounding floor from chip , excess coolant and oil
18
19
18
WORK PREPARATION
Student name
Subject
Job name
Sketch
:
: Mechanical Workshop
:
No.
Operations
Machine name :
Material
:
Time
:
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
20
Sketch
No.
Operations
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
21
Sketch
Cs : Cutting speed, m/min
No.
Operations
n : Spindle speed, rpm
Prepared by
Student,
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
f : feed, mm/min
Approved by
Instructor,
22
Evaluation Sheet
Student Name : ………………………..
Start
: …………
Group/Class
: ………………………..
Finish
: ………….
Job Name
: Bench work
Duration
: ………….
Weight
20%
70%
10%
Evaluation items
Measurement
Result
Mark
Max
A. Process
1. Use of tools
2. Working steps
3. Machne & Tool safety
4. Machine & tool maintenance
5. Work attitude
4
4
4
4
4
B. Product
1. Length 75 mm
2. Width 65 mm
3. Fillet R 10 mm
4. Chamfer 5x45o
5. Hole 1 position
6. Hole 2 position
7. Hole 3 position
8. Hole 4 position
9. Surface roughness
9
9
9
9
7
7
7
7
6
B. Time
1. According to allocated time
2. Faster than allocated time
3. Slower than allocated time
8
10
6
Total
Instructor:
Date:
23
Module 2 Milling
TOPICS
Face Milling and Pocketing
24
Specific Objectives
After you have studied this course and completed all the exercises
you will be able to:
1. Identify work safety aspects on working with milling machine,
including the safety for tools and machine
2. Use the milling machine to do facing operation using the right tools
and machining parameters, with the right way and attitude
3. Use the milling machine to do pocketing operation using the right
tools and machining parameters, with the right way and attitude
4. Apply autonomous machine maintenance by cleaning and oiling the
machine and tools after use.
25
Fundamental of Milling
Milling is a process performed with a machine in which the cutters
rotate to remove the material from the work piece at a certain direction. The
cutter may also be held at an angle relative to the tool axis. With the help of
the milling machines one can perform many operations to form the
workpiece into a various shape of products.
Milling Machine Function
Milling machining is one of the very common manufacturing processes used
in machinery shops and industries to manufacture high precision products
and parts in different shapes and sizes.
Types of Milling Machine
1. Vertical Milling Machine
2. Horizontal Milling Machine
Figure 9 Verticall Milling Machine (left) and Horizontal Milling Machine (right)
26
Components of Milling Machine
1. Column & Base. Column including base is the main casting that
supports all other parts of milling machine. The column contains an oil
reservoir and a pump which lubricates the spindle. The column rests on
the base and base contains coolant reservoir and a pump which is used
during machining operation that requires coolant.
2. Knee. It is a casting that supports the saddle and table. All gearing
mechanism is enclosed within the knee. It is fastened to the column by
dovetail ways. The knee is supported and adjusted by a vertical
positioning screw (elevating screw). The elevating screw is used to
adjust the knee up and down by raising or lowering the lever either with
the help of hand or power feed.
3. Saddle and Swivel Table. Saddle is present on the knee and supports
the table. It slides on a horizontal dovetail on the knee and dovetail is
parallel to the axis of the spindle ( in horizontal milling m/c). The swivel
table (in universal machines only) is attached to the saddle that can be
swiveled (revolved) horizontally in either direction.
4. Power Feed Mechanism. It is the knee which contains the power feed
mechanism. It is used to control the longitudinal ( left and right),
transverse ( in and out) and vertical (up and down) feeds. To get the
desired rate of feed on the machine, the feed selection lever is
positioned as indicated on the feed selection plates. On some universal
knee and column milling machine, the feed is obtained by turning the
speed selection handle until the desired rate of feed is indicated on the
feed dial. Most of the milling machines have a rapid traverse lever that
can be engaged when a temporary increase in the speed of the
longitudinal, transverse or vertical feeds is required. For example this
lever would be engaged when the operator is positioning or aligning the
work.
27
Figure 10 Vertical Milling Machine components
5. Table. It is a rectangular casting which is present on the top of the
saddle. It is used to hold the work or work holding devices. It contains
several T-slots for holding the work and work holding devices (i.e. jigs
and fixtures). The table can be operated by hand or by power.To move
the table by hand, engage and turn the longitudinal hand crank. To move
it through power, engage the longitudinal direction feed control lever.
6. Spindle. It is the shaft which is used to hold and drives the cutting tools
of the milling machine. Spindle is mounted on the bearings and
supported by the column. Spindle is driven by the electric motor through
gear trains. The gear trains are present within the column. The face of
the spindle which lies near to the table has an internal taper machined
28
on it. The internal taper at the front face of the spindle permits only
tapered cutter holder or arbor. It has two keys at the front face which
provides positive drive for the cutter holder or arbor. The drawbolt and
jamnut is used to secure the holder and arbor in the spindle.
Figure 11 Horizontal Milling Machine components
7. Over Arm / Overhanging Arm. It is a horizontal beam present at the
top face of the column. It may be a single casting which slides on the
dovetail ways present on the top face of the column. The overarm is
used to fastened arbor support. It may consist of one or two cylindrical
bars which slide through the holes in the column.
8. Arbor Support. It is a casting with bearing that supports the outer end
of the arbor. It also helps in aligning the outer end of the arbor with the
spindle. It prevents the springing of outer end of the arbor during cutting
operations. There are generally two types of arbor supports used in the
29
milling machine. The first one has small diameter bearing hole, 1-inch in
maximum diameter. And the other one has large diameter bearing hole,
usually upto 23/4 inches. The arbor support has an oil reservoir that
lubricates the bearing surfaces. It can be clamped anywhere on the
overarm. The arbor support is used only in the horizontal types of milling
machine.
9. Ram. The overhanging arm in the vertical machine is called ram. One
end of the ram is mounted on the top of the column and on the other end
milling head is attached.
Calculation of feed and spindle speed
Cutting Speed
When the milling process takes place, the rotating tool cut the moving
workpiece and produce cuts or incisions that resemble chip, the flakes can
also be shaped like powder (depending on the material). The machine
ability produces an incision length every minute called cutting speed (Vc),
which can be calculated with the following formula:
Where:
Vc
Cutting Speed (m/min)
D
Cutter Diameter (mm)
π
3.14
n
Main Axis Spindle Speed (rpm)
30
Spindle Speed
Since the cutting speed is normally known in advance from many
sources, we can use the same formula to calculate the spindle speed
required to do milling process, as follows:
Table 2 Cutting speed (Vc) for selected materials and cutting tools
HSS
Carbide
Material
Fine cut
Rough cut
Fine cut
Rough cut
Tool steel
75 - 100
25 – 45
185 - 230
110 - 140
Low carbon steel
70 - 90
25 - 40
170 - 215
90 - 120
Mild carbon steel
60 - 85
20 - 40
140 - 185
75 – 110
Cast iron
40 – 45
25 - 30
110 - 140
60 – 75
Bronze
85 – 110
45 - 0
185 – 215
120 – 150
Aluminum
70 – 110
30 - 45
140 - 215
60 - 90
Example
What is the spindle speed for fine milling when the workpiece material is
aluminum, the tools is carbide and the tool diameter is Ø10? Substitute
π=3.14,
Answer
Substitute π =3.14, D= 10, into the formula.
Let’s take Vc = 120 m/min
n = (Vc × 1000) / π x D
= (120 × 1000) / 3.14 x 10
= 3821 (rpm)
Spindle speed is ≈ 3800 rpm.
31
Table 3 Milling Feed & Cutting speed
32
Feed per Tooth (fz)
A value for calculating the table feed. The feed per tooth value is
calculated from the recommended maximum chip thickness value.
Table Feed (vf)
Also known as machine feed, or feed speed. It is the feed of the tool in
relation to the workpiece in distance per time unit related to feed per tooth
and number of teeth in the cutter. The number of available cutter teeth in the
tool (z) varies considerably and is used to determine the table. Feed per
revolution (f) in mm/rev is a value used specifically for feed calculations and
often to determine the finishing capability of a cutter.
vf
Table Feed (mm/min)
z
Insert Number
fz
Feed per Tooth (mm/tooth)
n
Main Axis Spindle Speed (rpm
)
Problem
What is the table feed when feed per tooth is 0.1mm/tooth, insert
number is 10, and main axis spindle speed is 500 rpm?
Answer
Substitute the above figures into the formula.
vf= fz×z×n = 0.1×10×500 = 500 mm/min
The table feed is 500 mm/min.
33
Milling Exercise
Safety Guidelines
1. Use safety protection device such as safety glasses, gloves, safety
shoes, etc.
2. Do not use surface plate measurement table for placing sharp and
heavy tools other than measurement tools.
3. Get used to place tools and measurement tools at safe place and
do not place on top of each other.
4. Use the tool according to its function.
Material, Machine and Tools
1. Aluminum 5083 plate, size 65x75x17 mm
2. Vertical Milling Machine and tools:
a. Spindle adaptor
b. Collet
c. Tightening and removing tools
3.Measurement tools:
a. Vernier Caliper
b. Bevel protector
4.Cutting tools:
a. Flat end mill Ǿ20 mm
b. Flat end mill Ǿ10 mm
c. Counter sink for hole deburring
5.Cooling oil and applicator
34
Operation Steps:
1. Preparation:
a. Hold and secure the work piece on table vise, use parallel plate to
support and apply rubber/plastic hammering if necessary. Do not
use hammer to tighten the vise.
b. Prepare cooling oil and applicator.
2. Facing
a. Select the spindle speed according to tool diameter and work piece
material.
b. Hold Ǿ20 mm cutter in machine spindle, use appropriate holding
device such as collet, adaptor, or chuck.
c. Do facing at 1 mm depth, using back and forth motion. Apply step
over and overhang about half of cutter diameter.
3. Pocketing
a. Select the spindle speed according to tool diameter and work piece
material.
b. Hold Ǿ10 mm cutter in machine spindle, use appropriate holding
device such as collet, adaptor, or chuck.
c. Do pocketing at 1 mm depth, using spiral motion from outside
inward. Apply step over about half of cutter diameter.
d. Move the cutter down 1 mm at initial position, and do next level of
pocketing.
e. Do level by level pocketing at max depth of cut of 1 mm, until reach
the depth 0f 9.5 mm
35
f. Do pocket finishing until the depth of 10 mm.
4. Cleaning and oiling
a. Remove and clean the tools and holding devices
b. Clean the machine from chip and excess coolant
c. Apply oil on machine surface to prevent rust.
d. Clean the surrounding floor from chip , excess coolant and oil
36
37
WORK PREPARATION
Student name
Subject
Job name
Sketch
:
: Mechanical Workshop
:
No.
Operations
Machine name : MILLING
Material
: AL 5083
Time
:
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
38
Sketch
No.
Operations
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
39
Sketch
No.
Cs : Cutting speed, m/min
Operations
n : Spindle speed, rpm
Prepared by
Student,
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
f : feed, mm/min
Approved by
Instructor,
40
Evaluation Sheet
Student Name
: ………………………..
Start
: …………
Group/Class
: ………………………..
Finish
: ………….
Job Name
: Pocket Milling
Duration
: ………….
Weight
Evaluation items
Measurement
Result
Mark
Max Total
A. Process
20%
1. Use of tools
4
2. Working steps
4
3. Machne & Tool safety
4
4. Machine & tool maintenance
4
5. Work attitude
4
B. Product
70%
1. Pocket length 65 mm
18
2. Pocket width 40 mm
18
3. Pocket depth 10 mm
14
4. Top Face roughness
10
5. Pocket surface roughness
10
B. Time
10%
1. According to allocated time
8
2. Faster than allocated time
10
3. Slower than allocated time
6
Instructor:
Date:
41
Module 3 Turning
TOPICS
Facing, Flat Turning, Step Turning
Drilling, Chamfering
42
Specific Objectives
After you have studied this course and completed all the exercises you
will be able to:
1. Identify work safety aspects on working with lathe machine,
including the safety for tools and machine
2. Use the lathe machine to do facing operation using the right
tools and machining parameters, with the right way and
attitude
3. Use the lathe machine to do flat turning operation using the
right tools and machining parameters, with the right way
and attitude
4. Use the lathe machine to do step turning operation using
the right tools and machining parameters, with the right way
and attitude
5. Use the lathe machine to do drilling or internal turning
operation using the right tools and machining parameters,
with the right way and attitude
6. Apply autonomous machine maintenance by cleaning and
oiling the machine and tools after use.
43
Fundamental of Lathe
Lathe is one of the machine tools used to process raw material by
removing certain part of the workpiece to obtain a particular shape. Material
removal is done by means of incision, wherein the workpiece rotates at a
certain speed and the lathe tool moves in a translational manner parallel to
the rotary axis of the workpiece. The swivel movement of the workpiece is
called the relative cutting motion and the translational motion of the tool is
called the feeding motion. Lathe objects usually have a cylindrical cross
section. With a lathe we can make cylindrical material into straight, tapered,
threaded and grooved rounded shapes.
Lathe Function
Lathe Machine has a function to shape a different form of material,
surface turning, drilling, reaming, threading, hole, stepped cylinder, knurling,
etc. Material that can be process with a lathe can be wood, mild steel
(SS400), Carbon steel, Aluminum, stainless steel, brass, bronze, teflon,
PVC, PP or other non-metallic material. The turning process is usually to
make product in the form of shafts, cylinder rods, tubes, pipes, bolts, nuts,
pins or other round objects.
Components of Lathe
1. Bed: Usually made of cast iron. Provides a heavy rigid frame on
which all the main components are mounted.
2. Ways: Inner and outer guide rails that are precision machined
parallel to assure accuracy of movement.
3. Headstock: mounted in a fixed position on the inner ways, usually
at the left end. Using a chuck, it rotates the work.
4. Gearbox: inside the headstock, providing multiple speeds with a
geometric ratio by moving levers.
44
45
5. Spindle: Hole through the headstock to which bar stock can be fed,
which allows shafts that are up to 2 times the length between lathe
centers to be worked on one end at a time.
6. Chuck: 3-jaw (self centering) or 4-jaw (independent) to clamp part
being machined.
7. Face plate: allows the mounting of difficult workpieces that are not
round, square or triangular.
8. Carriage: Moves on the outer ways. Used for mounting and moving
most the cutting tools.
9. Cross Slide: Mounted on the traverse slide of the carriage, and
uses a handwheel to feed tools into the workpiece.
10. Tool Post: To mount tool holders in which the cutting bits are
clamped.
11. Top Slide: Mounted to the cross slide, it pivots around the tool post.
12. Apron: Attached to the front of the carriage, it has the mechanism
and controls for moving the carriage and cross slide.
13. Saddle: The carriage typically comprises a top casting known as
saddle.
14. Split Nut: When closed around the lead screw, the carriage is
driven along by direct drive without using a clutch.
15. Quick Change Gearbox: Controls the movement of the carriage
using levers.
16. Handwheels: for moving carriage, cross slide, or top slide
manually,
46
17. Feed Rod: Has a keyway, with two reversing pinion gears, either of
which can be meshed with the mating bevel gear to forward or
reverse the carriage using a clutch.
18. Lead Screw: For cutting threads.
19. Tailstock: Fits on the inner ways of the bed and can slide towards
any position the headstock to fit the length of the work piece. An
optional taper turning attachment would be mounted to it.
20. Tailstock Quill: Has a Morse taper to hold a lathe center, drill bit or
other tool.
21. Steady Rest: Clamped to the lathe ways, it uses adjustable fingers
to contact the workpiece and align it. Can be used in place of
tailstock or in the middle to support long or unstable parts being
machined.
22. Follow Rest: Bolted to the lathe carriage, it uses adjustable fingers
47
to bear against the workpiece opposite the cutting tool to prevent
deflection.
23. Coolant outlet: channeling the coolant fluid
24. ON/OFF button: to switch ON or OFF the machine.
25. Brake pedal: to stop quickly the machine rotation.
48
Calculation of feed and spindle speed
Cutting Speed
When the turning process takes place, the steady still tool cut the
rotating workpiece and produce cuts or incisions that resemble chip, the
flakes can also be shaped like powder (depending on the material). The
machine ability produces an incision length every minute called cutting
speed (Vc), which can be calculated with the following formula:
Where:
Vc
Cutting Speed (m/min)
D
Workpiece Diameter (mm)
π
3.14
n
Main Axis Spindle Speed (rpm)
Spindle Speed
Since the cutting speed is normally known in advance from many
sources, we can use the same formula to calculate the spindle speed
required to do turning process, as follows:
49
Table 4 Cutting speed (Vc) for selected materials and cutting tools
HSS
Carbide
Material
Fine cut
Rough cut
Fine cut
Rough cut
Tool steel
75 - 100
25 – 45
185 - 230
110 - 140
Low carbon steel
70 - 90
25 - 40
170 - 215
90 - 120
Mild carbon steel
60 - 85
20 - 40
140 - 185
75 – 110
Cast iron
40 – 45
25 - 30
110 - 140
60 – 75
Bronze
85 – 110
45 - 0
185 – 215
120 – 150
Aluminum
70 – 110
30 - 45
140 - 215
60 - 90
Example
What is the spindle speed for rough cutting when the workpiece
material is aluminum, the tools is carbide and the external diameter is Ø50?
Substitute π=3.14,
Answer
Substitute π =3.14, D= 50, into the formula.
Let’s take Vc = 80 m/min
n = (Vc × 1000) / π x D
= (80 × 1000) / 3.14 x 50
= 509 (rpm)
Spindle speed is 509 rpm.
50
Feed (f)
The distance the tool advances into the material in one revolution is
called "feed". It is specified as mm per revolution (mm/rev).
Where:
f
Feed per revolution (mm/rev.)
l
Cutting length per Min (mm/min)
n
Main Axis Spindle Speed (rpm)
Example
What is the feed per revolution when main axis spindle speed is 500 rpm
and cutting length per minute is 120mm/min ?
Answer
Substitute n=500, I=120 into the formula f = l / n = 120 / 500= 0.24 (mm/rev)
The answer is 0.24 mm/rev.
47
51
Turning Exercise
Safety Guidelines
1. Use safety protection device such as safety glasses, gloves, safety
shoes, etc.
2. Do not use surface plate measurement table for placing sharp and
heavy tools other than measurement tools.
3. Get used to place tools and measurement tools at safe place and do
not place on top of each other.
4. Use the tool according to its function.
Material, Machine and Tools
1. Aluminum 5083 round bar Ǿ20 x 45 mm
2. Horizontal Lathe Machine and tools:
a. Drill chuck
b. Tightening and removing tools
3. Measurement tools:
a. Vernier Caliper
4. Cutting tools:
a. Facing tool
b. Flat turning tool
c. Chamfering tool
d. Centre drill
e. Drill bit Ǿ6 mm and Ǿ12 mm
5. Counter sink for hole deburring 5.Cooling oil and applicator
52
Operation Steps:
1. Preparation:
a. Hold and secure the work piece in three jaws chuck. Allow 20 mm
length inside the chuck
b. Make sure the work piece is concentric with machine spindle axis.
c. Prepare cooling oil and applicator.
2. Facing
a. Select and adjust the facing tool at the right position
b. Select the spindle speed according to work piece diameter and
material.
c. Do facing with light cut until flat.
3. Step turning
a. Select and adjust the tool at the right position
b. Select the spindle according to tool diameter and work piece
material.
c. Do turning of Ǿ16 mm at 20 mm length
d. Do turning of Ǿ8 mm at 15 mm length
e. Do chamfering 0.5 x 45o
f.
Remove the work piece from chuck
4. Flat turning
a. Select and adjust the tool at the right position
b. Select the spindle according to tool diameter and work piece
material.
c. Reverse the workpiece to cut another end, and hold in the chuck at
least 15 mm length
d. Do turning of Ǿ14 mm at 25 mm length
e. Do chamfering 0.5 x 45o
53
Do NOT remove the work piece from chuck
5. Drilling
a. Select the spindle according to centre drill diameter and work
piece material
b. Hold and secure the drill chuck at tail stock.
c. Hold the centre drill in drill chuck
d. Start drilling until aboout 1 mm depth
e. Change the centre drill with 6 mm drill bit
f. Drill until depth of 23 mm
g. Change the 6mm drill bit with 10 mm drill bit
h. Drill until depth of 23 mm
i. Change 10 mm drill bit with counter sink tool
j. Do hole deburring using counter sink tool
k. Remove the work piece
6. Cleaning and oiling
a. Remove and clean the tools and holding devices
b. Clean the machine from chip and excess coolant
c. Apply oil on machine surface to prevent rust.
d. Clean the surrounding floor from chip , excess coolant and oil
54
55
51
WORK PREPARATION
Student name
Subject
Job name
Sketch
:
: Mechanical Workshop
:
No.
Operations
Machine name : LATHE
Material
: AL 5083
Time
:
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
56
Sketch
No.
Operations
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
57
Sketch
No.
Cs : Cutting speed, m/min
Operations
n : Spindle speed, rpm
Prepared by
Student,
Est.
Time
Clamping
Device
Cutting tools
Cs
n
f
Measuring tool
f : feed, mm/min
Approved by
Instructor,
58
Evaluation Sheet
Student Name
: ………………………..
Start
: …………
Group/Class
: ………………………..
Finish
: ………….
Job Name
: Pen Holder Turning
Duration
: ………….
Weight
Evaluation items
Measurement
Result
Mark
Max
Total
A. Process
20%
1. Use of tools
4
2. Working steps
4
3. Machne & Tool safety
4
4. Machine & tool maintenance
4
5. Work attitude
4
B. Product
70%
1. Diameter 16 mm
9
2. Diameter 14 mm
9
3. Diameter 8 mm
9
4. Hole Diameter 10
7
5. Length 25 mm
7
6. Length 5 mm
7
7. Length 15 mm
7
8. Hole Depth 23 mm
7
9. Surface roughness
8
B. Time
10%
1. According to allocated time
8
2. Faster than allocated time
10
3. Slower than allocated time
6
Instructor:
Date:
59
Module 4 Welding
TOPICS
Butt Joint Welding & T Joint Welding
60
Specific Objectives
After you have studied this course and completed all the exercises you
will be able to:
1. Identify work safety aspects on welding operation, including the
safety for tools and machine
2. Use the welding machine to do butt join welding operation using the
welding parameters, with the right way and attitude
3. Use the welding machine to do T join welding operation using the
welding parameters, with the right way and attitude
4. Apply autonomous maintenance by cleaning the machine and tools
after use.
61
Fundamental of Welding
Welding is the process of joining
metal
permanently.
Welding
processes are generally classified into three basic categories:
1. Fusion welding
2. Solid-state welding
3. Brazing and soldering.
Fusion Welding is defined as the melting together and coalescing of
materials by means of heat, usually supplied by chemical or electrical
means; filler metals may or may not be used. Fusion welding is composed
of consumable and non-consumable electrode arc Welding and highenergy-beam Welding processes. Below are the example of join that can be
made by weldinng process.
Figure 12 Types of welding
1. Oxyfuel-gas welding (OFW) is a general term used to describe any
welding process that uses a fuel gas combined with oxygen to produce a
flame. The flame is the source of the heat that is used to melt the metals
at the joint. The most common gas welding process uses acetylene; the
process is known as oxyacetylene-gas welding (OAW) and is typically
used for structural metal fabrication and repair work. Developed in the
early 1900s, OAW utilizes the heat generated by the combustion of
acetylene gas (CZHZ) in a mixture with oxygen.
62
Figure 13 Oxyfuel gas welding
2. Arc Welding, developed in the mid-18005, the heat required is obtained
from electrical energy. The process involves either a consumable or a
non-consumable electrode. An AC or a DC power supply produces an
arc between the tip of the electrode and the workpiece to be welded.
The arc generates temperatures of about 30,000°C, which are much
higher than those developed in oxyfuel-gas welding.
In non-consumable electrode welding processes, the electrode is
typically a tungsten electrode. Because of the high temperatures
involved, an externally supplied shielding gas is necessary to prevent
oxidation of the weld zone. Typically, direct current is used, and its
polarity (the direction of current flow) is important.
Figure 14 Gas Tungsten Arc welding
63
a. Gas Tungsten-arc Welding. In gas tungsten-are welding (GTAW),
formerly known as TIG (for “tungsten inert gas”) welding, the filler
metal is supplied from a filler wire. Because the tungsten electrode is
not consumed in this operation, a constant and stable arc gap is
maintained at a constant current level. The filler metals are similar to
the metals to be welded, and flux is not used. The shielding gas is
usually argon or helium (or a mixture of the two). Welding with GTAW
may be done without filler metals-for example, in the welding of closefit joints.
b. Plasma-arc Welding. In plasma-arc welding (PAW), developed in the
1960s, a concentrated plasma arc is produced and directed towards
the weld area. The arc is stable and reaches temperatures as high
as 33,000°C. A plasma is an ionized hot
c. gas composed of nearly equal numbers of electrons and ions. The
plasma is initiated betweenthe tungsten electrode and the orifice by a
low-current pilot arc. What makes plasma-arc welding unlike other
processes is that the plasma arc is concentrated because it is forced
through a relatively small orifice.
d. Atomic-hydrogen Welding. In atomic-hydrogen welding (AHW), an
arc is generated between two tungsten electrodes in a shielding
atmosphere of hydrogen gas. The arc is maintained independently of
the workpiece or parts being welded. The hydrogen gas normally is
diatomic (HZ), but where the temperatures are over 6,000°C near
the
arc,
the hydrogen breaks down into its atomic form,
simultaneously absorbing a large amount of heat from the arc. When
the hydrogen strikes the cold surface of the workpieces to be joined, it
recombines into its diatomic form and rapidly releases the stored
heat.
On the other hand, there are several consumable-electrode arc- welding
64
processes:
a. Shielded Metal-arc Welding, (SMAW) is one of the oldest,
simplest, and most versatile joining processes. About 5 0% of all
industrial and maintenance welding currently is performed by this
process. The electric arc is generated by touching the tip of a coated
electrode against the workpiece and withdrawing it quickly to a
distance sufficient to maintain the arc. The electrodes are in the
shapes of thin, long rods that are held manually. A bare section at
the end of the electrode is clamped to one terminal of the power
source, while the other terminal is connected to the workpiece being
welded. The current, which may be DC or AC, usually ranges from
50 to 300 A.
Figure 15 Shielded Metal Arc Welding
b. Submerged-arc Welding. In submerged-arc welding (SAW), the
weld arc is shielded by a granular flux consisting of lime, silica,
manganese oxide, calcium fluoride, and other compounds. The flux
is fed into the weld zone from a hopper by gravity flow through a
nozzle. The thick layer of flux completely covers the molten metal. It
prevents spatter and sparks and suppresses the intense ultraviolet
radiation and fumes characteristic of the SMAW process. The flux
also acts as a thermal insulator by promoting deep penetration of
65
heat into the workpiece. The unused flux can be recovered (using a
recovery tube), treated, and reused.
Figure 16 Sub Merged Arc Welding
c. Gas Metal-arc Welding. In gas metal-arc welding (GMAW),
developed in the 19505 and formerly called metal inert-gas (MIG)
welding, the Weld area is shielded by an effectively inert atmosphere
of argon, helium, carbon dioxide, or various other gas mixtures. The
consumable bare Wire is fed automatically through a nozzle into the
Weld arc by a Wire-feed drive motor. In addition to using inert
shielding gases, deoxidizers usually are present in the electrode
metal itself in order to prevent oxidation of the molten-weld puddle.
Multiple-weld layers can be deposited at the joint.
Figure 17 Gas Mertal Arc Welding
66
d. Flux-cored Arc Welding. The flux-cored arc welding (FCAW)
process is similar to gas metal-arc Welding, except that the
electrode is tubular in shape and is filled with flux (hence the term
flux-cored). Cored electrodes produce a more stable arc, improve
weld contour, and produce better mechanical properties of the weld
metal. The flux in these electrodes is much more flexible than the
brittle coating used on SMAW electrodes, so the tubular electrode
can be provided in long coiled lengths.
Figure 18 Flux cored Arc welding
67
Shielded Metal Arc Welding
Exercise
Safety Guidelines
1. Use safety protection device such as welding google or welding mask ,
gloves, safety shoes, etc.
2. Get used to place tools and measurement tools at safe place and do
not place on top of each other.
3. Use the tool according to its function.
Material, Machine and Tools
1. Steel plate, size 40x100x 3 mm: 4 pieces
2. Welding Machine
3. Electrode RB 26 - 2,6 mm
4. Clamping tools, welding hammer
5. Steel square:
Operation Steps:
Butt joint Welding:
a.
Position the materials with 2-3 mm distance from each other
b.
Select welding current at about 70-80 A
c.
Place welding electrode in the holder
d.
Turn On the machine
e.
Start welding until finish
68
Figure 19 Butt join welding
T joint Welding:
a. Position the materials at T position from each other
b. Select welding current at about 70-80 A
c. Place welding electrode in the holder
d. Start welding until finish
Cleaning
a. Remove and clean the tools and holding devices
b. Clean the machine from excess materials
c. Clean the surrounding floor
Figure 20 T join welding
69
Evaluation Sheet
Student Name
: ………………………..
Start
: …………
Group/Class
: ………………………..
Finish
: ………….
Job Name
: Butt and T Join Welding
Duration
: ………….
Weight
Evaluation items
Measureme
nt Result
Mark
Max
Total
A. Process
20%
1. Use of tools
4
2. Working steps
4
3. Machne & Tool safety
4
4. Machine & tool maintenance
4
5. Work attitude
4
B. Product
70%
1. Joint continuity
9
2. Completeness of Fusion
9
3. Completeness of Penetration
9
4. No Undercut
7
5. No slug Inclusion
7
6. No porosity
7
7. No Crack
7
8. No warpage
7
9. No spatter
8
B. Time
10%
1. According to allocated time
8
2. Faster than allocated time
10
3. Slower than allocated time
6
Instructor:
Date:
70