MANUFACTURING PROCESS

LAB MANUAL

Lab Report

Section – C

Submitted By:
Waqar Ahmed BSME01183097

Submitted To:
Sir Mustafa Haider

Submission Date:
11th January,2021

DEPARTMENT OF MECHANICAL
ENGINEERING
 LIST OF APPARATUSES

1) Vernier Caliper
2) Micrometer Screw Gauge
3) Hand Operated Injection Molding Machine
4) Solder Iron
5) 250 Amp Welding Machine
6) Power Press
7) Shaper Machine
8) Surface Grinder
9) Horizontal Milling Machine
10) Vertical Milling Machine
11) Lathe Machine
12) CNC Wire Cut Machine
13) Drilling Machine
14) CNC Lathe Machine

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 LIST OF EXPERIMENTS
1) To make different shape products of PVC using hand injection
molding machine
2) To join two or more metals by melting a filler metal (solder)
3) Arc Welding
a) To generate an arc and create a bead
b) To perform the arc welding process to join the two metals using
electrode and welding machine
c) To perform the arc welding process to join the two metals using
electrode and welding machine
d) To make a metallic box using welding process
4) To perform a sheet metal cutting process using power press
5) To prepare horizontal and vertical surface by using shaper
6) To smooth the surface of a flat work piece by using surface grinder
7) To make a spur gear on a horizontal milling machine
8) Vertical Milling Machine
a) To make a hexagonal shape on vertical milling machine
b) To perform circular machining using rotary table
c) To perform different surface machining process using shell end
mill cutters
9) Lathe Machine
a) To do facing and straight turning on job after job centering and
tool centering
b) To do taper turning using compound slide on same job
10) EDM Wire cut
a) Introduction to EDM Wire cut and job references
b) To prepare a job using EDM Wire cut for external cutting
c) To prepare a job using EDM Wire cut for internal cutting
11) To prepare a job by marking punch and drill holes on the metal sheet
using drilling machine and tapping for internal threading

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12) CNC Lathe machine
a) Introduction to CNC Lathe machine and understanding to its
work coordinate system (Absolute and increment system) and
program making for facing and turning processes
b) To make different radii of a job by using CNC Lathe
c) To do internal and external taper turning using CNC Lathe
d) To perform rough and finish turning cycles using CNC Lathe

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 LAYOUT OF MANUFACTURING PROCESSES LAB
SAFETY IN THE MACHINE SHOP
OBJECTIVES
After completing this activity, the students will be able to:
• Identify the safe and unsafe work practices in a shop
• Identify and correct the potential hazards in the shop area
• Performing the required job in a suitable and safe way.

INTRODUCTION
All hand and machine tools can be dangerous if used improperly or carelessly. Working
safely is one of the first things a student should learn because the safe way is usually
the correct and most efficient way.

SAFETY IN THE SHOP

Safety in a machine shop may be divided into two broad categories:
• Those practices that will prevent injury to workers.
• Those practices that will prevent damage to machines and equipment.

PERSONAL GROOMING
1. Always wear approved safety glasses in any area of the machine shop.
• Plain Safety Glasses with side shields
• Plastic Safety Goggles
• Face Shields
Never think that because you are wearing glasses your eyes are safe. If the lenses are
not made of approved safety shatterproof glass, serious eye injury can still occur.

2. Never wear loose clothing when operating any machine.

• Always roll up your sleeves or wear short sleeves
• Remove or tuck in a necktie before starting a machine
• Remove wrist watches, rings, and bracelets; these can get caught in the machine,
causing painful and often serious injury
• Never wear gloves when operating a machine.

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 • Long hair must be protected by a hair net
• Canvas shoes or open-toed sandals must never be worn in a machine shop
because they offer no protection to the feet against sharp chips or falling objects

HOUSEKEEPING
• Always stop the machine before you attempt to clean it.
• Always keep the machine and hand tools clean
• Always use a brush and not a cloth to remove any chips
• Oily surfaces should be cleaned with a cloth.
• Do not place tools and materials on the machine table use a bench near the
machine.
• Keep the floor free from oil and grease.
• Never place tools or materials on the floor close to a machine where they will
interfere with the operator's ability to move safely around the machine.
• Never use compressed air to remove chips from a machine.

SAFE WORK PRACTICES

• Do not operate any machine before understanding its mechanism and knowing
how to stop it quickly
• Always disconnect the power and lock it off at the switch box when making
repairs to any machine. Place a sign on the machine noting that it is out of order.
• Always be sure that the cutting tool and the work piece are properly mounted
before starting the machine
• Keep hands away from moving parts
• Always stop a machine before measuring, cleaning, or making any adjustments
• Do not attempt to lift heavy or odd-shaped objects that are difficult to handle on
your own.
• Be sure the work is clamped securely in the vise or to a machine table.
• It is safer to pull on a wrench than to push on it.

FIRE PREVENTION
• Know the location and the operation of every fire extinguisher in the shop.
• Know the location of the nearest fire exit from the building.

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7
 INTRODUCTION TO THE MEASURING TOOLS
PART 1
OBJECTIVE
To measure the dimensions of a given sample using Vernier caliper
APPARATUS
Vernier Caliper, Given Sample

DESCRIPTION
A Vernier calipers consists of mainly two parts
i) A 2cm wide 15cm long rectangular metal strip .The left end bottom side of
this strip consists of a fixed jaw 1 (A) and at the same end jaw 2(C) at the top
of this strip. On the strip a scale (5) is graduated in Inches along the upper
edge and another scale (4) is graduated in Centimeters along the lower edge.
This is called Main Scale ‘S’.
ii) ii) A metal frame V called vernier slides over the Main Scale ‘S’. At the
bottom of this frame V a button 8(P) is attached, which helps to fix this
vernier at any desired place on the main scale. This verier frame consists of
jaw1 (B) at the bottom and a jaw 2(D) at the top .Two scales are graduated on
this frame corresponding to two scales on the Main Scale ‘S’. The two scales
6 and 7 on the vernier are called Vernier scale.Vernier scale consists of
equal number of divisions. When we move vernier frame over the main scale,
a thin strip (3) will be projected out. The projection will be exactly equal to
the distance between Jaws 1(AB) i.e. the thickness of the object between
jaws.

The lower jaws 1, 1(AB) are used to measure the thickness or external diameter of the
tubes, cylinders or spheres.

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The upper jaws 2, 2 (CD) are used to measure the inner diameters of hallow bodies
like tubes or holes. The thin strip (3) is used to measure the depth of the objects
like test tubes.

THEORY

Principle of vernier calipers – N divisions on the vernier scale is equal to (N-1)

divisions on the main scale.

N(V.S.D) = (N-1) M.S.D

1 V.S.D = (𝑁−1 ) M.S.D

𝑁

Least count (L.C) of vernier calipers: Minimum length or thickness measurable with
the vernier calipers is called its least count.

Least count (L.C) = 1 M.S.D – 1 V.S.D

𝑁−1
L.C = 1 M.S.D – ( )M.S.D
𝑁

L.C = 1 M.S.D [1- 𝑁−1]

𝑁

1 𝑀.𝑆.𝐷 𝑆
L.C = =
𝑁 𝑁

Where S is the value of one Main scale division and N is the number of equal
divisions on the vernier scale.

PROCEDURE

First we have to determine the least count of the given vernier calipers.

To determine the volume of the cylinder we have to determine a) the length of the
cylinder and b) radius of the cylinder and substituting these values in the equation for
the volume of the cylinder we can calculate it.

1) TO DETERMINE THE LENGTH OF THE CYLINDER

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 Given cylinder is held gently between jaws 1, 1 of the vernier calipers. The
reading on the main scale just before the zero of the vernier is noted. This is called
Main scale reading (M.S.R).The number of division (n) on the vernier which
coincides perfectly with any one of the main scale divisions is noted. This is
called vernier coincidence (V.C). The vernier coincidence (V.C=n) is multiplied
by least count to get the fraction of a main scale division. This is added to the
main scale reading (M.S.R) to total reading or total length of the cylinder.

Total reading = M.S.R + (V.C * L.C)

Take the readings, keeping the cylinders between jaws 1, 1 at different positions. Post
the values of M.S.R and vernier coincidence (n) in the table. Take at least 5 readings;
get the average of these 5 readings which is mean length (l) of the cylinder.

2) TO DETERMINE THE DIAMETER OF THE CYLINDER

Place the cylinder diametrically between the jaws 1,1 of the vernier calipers, as in the
above case post the values of M.S.R and vernier coincidence (n) in the table. Take at
least 5 readings, calculate the average of these readings which gives the mean
diameter (d=2r) of the cylinder.

3) TO DETERMINE THE VOLUME OF THE CYLINDER

Substituting the values of mean length (l) of the cylinder and mean diameter (r) of the
cylinder which is already determined, in the formula 𝑉 = 𝜋𝑟2𝑙 𝑐𝑚3

OBSERVATIONS

I) LEAST COUNT OF VERNIER CALIPERS

a) Value of 1 Main scale division = 1 M.S.D = S =.............cm,

b) Number of divisions on the vernier scale N= ............. cm,

Least count L.C = 𝑆 = .............. cm.

𝑁

c) Zero error = x (positive error)

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II) VOLUME OF THE CYLINDER

A) LENGTH OF THE CYLINDER

M.S.R Total Reading

S.No Vernier Coincidence (n) Fraction b=(n-x)*L.C
a(cm) (a+b) cm

1.

2.

3.

4.

5.

Average length of the cylinder l = ……… cm.

B) DIAMETER OF THE CYLINDER

M.S.R Total Reading

S.No Vernier Coincidence (n) Fraction b=(n-x)*L.C
a(cm) (a+b) cm

1.

2.

3.

4.

5.

Average diameter of the cylinder d = 2r = .................. cm,

Mean radius of the cylinder r = d/2 = ................... cm,

Volume of the cylinder 𝑉 = 𝜋𝑟2 𝑙 𝑐𝑚3.

PART 2

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OBJECTIVE
To measure the dimensions of a given sample using micrometer screw gauge
APPARATUS

Micrometer Screw Gauge, Given Sample

DESCRIPTION OF MICROMETER SCREW GAUGE

Screw Gauge consists of U shaped metallic frame. To one side of this U frame a long
hallow cylindrical tube with a nut inside it, the inner side of cylindrical nut contains a
uniform thread cut in it. On the other side of U frame a fixed stud with a plane face
is attached.

A screw S2 is fitted in the cylindrical nut. One side of the screw S2 has a plane face
similar to that of stud. S1 The faces of S1 and S2 are plane and parallel to one another.
The other end of the screw S2 carries a milled head ‘H’ attached to a cap ‘C’ with a
sloping edge. When the head H is rotated, the screw moves” to and fro” in the nut.
The milled head H is provided with a safety device ‘D’ to rotate the head H. When the
object is held between the stud S1 , the screw S2 and the head H is rotated using the
safety device (D), it produces crackling sound when optimum pressure is applied on
the object.

The outer surface of long cylindrical nut consists of a thick horizontal line ‘P’ parallel
to the axis of cylindrical tube. This line ‘P’ is called Index line. Along the index line a
scale is graduated in millimeters. This scale is called Pitch Scale. On the sloping edge

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of the cap ‘C’ a circular scale is graduated, which consists of 100 equal divisions, this
scale is called Head scale.

THEORY

The screw gauge works on the principle of screw. When we rotate the head ‘H’ by
means of safety device ‘D’ through one complete rotation, the distance moved by the
screw for every complete rotation is constant. This constant distance moved by the
screw for one complete rotation of head ‘H ‘is called Pitch of the screw. If the head
scale has 100 equal divisions, then the distance moved by the screw for even 1/100 of
a complete rotation can be measured accurately, this is called least count of screw
gauge.

𝑃𝐼𝑇𝐶𝐻 𝑂𝐹 𝑇𝐻𝐸 𝑆𝐶𝑅𝐸𝑊

Therefore, least count (L.C) =
𝑁𝑈𝑀𝐵𝐸𝑅 𝑂𝐹 𝐷𝐼𝑉𝐼𝑆𝐼𝑂𝑁𝑆 𝑂𝑁 𝐻𝐸𝐴𝐷 𝑆𝐶𝐴𝐿𝐸

PROCEDURE

First we have to determine the least count of the given Screw gauge.

To determine the least, count of the screw gauge, the head ‘H’ is rotated through
certain (say 5) number of complete rotations. The distance moved by the sloped edge
over the pitch scale is measured.

Now substitute these values in the formula of pitch of the screw

𝐷𝐼𝑆𝑇𝐴𝑁𝐶𝐸 𝑀𝑂𝑉𝐸𝐷 𝐵𝑌 𝑆𝐿𝑂𝑃𝐸𝐷 𝐸𝐷𝐺𝐸 𝑂𝑉𝐸𝑅 𝑇𝐻𝐸 𝑃𝐼𝑇𝐶𝐻 𝑆𝐶𝐴𝐿𝐸

=
𝑁𝑈𝑀𝐵𝐸𝑅 𝑂𝐹 𝑅𝑂𝑇𝐴𝑇𝐼𝑂𝑁𝑆 𝑂𝐹 𝑇𝐻𝐸 𝑆𝐶𝑅𝐸𝑊

𝑃𝐼𝑇𝐶𝐻 𝑂𝐹 𝑇𝐻𝐸 𝑆𝐶𝑅𝐸𝑊

Least count L.C =
𝑁𝑈𝑀𝐵𝐸𝑅 𝑂𝐹 𝐷𝐼𝑉𝐼𝑆𝐼𝑂𝑁𝑆 𝑂𝑁 𝐻𝐸𝐴𝐷 𝑆𝐶𝐴𝐿𝐸

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Now check whether the given screw gauges have any ZERO ERROR or not. To
determine the ZERO ERROR, the head H is rotated until the flat end of the screw S-2
touches the plane surface of the stud S1 (do not apply excess pressure) i.e. we have to

rotate the head only by means of safety device ‘D’ only.

When S1 and S2 are in contact, the zero of the head scale perfectly coincides with the
index line as in Fig-(a). In such case there will be no ZERO ERROR and no
correction is required.

When S1 and S2 are in contact, the zero of the head scale is below the index line as in
Fig(b), such ZERO ERROR is called positive ZERO ERROR, and the correction is
negative.

When S1 and S2 are in contact, the zero of the head scale is above the index line as in
Fig(c), such ZERO ERROR is called negative ZERO ERROR, and the correction is
positive.

a) DETERMINE THE THICKNESS OF GLASS PLATE

The given object glass plate is held between the two parallel surfaces of fix stud S1
and screw tip S2. Note the completed number of divisions on pitch scale, which is
called PITCH SCALE READING (P.S.R). The number of the head scale division
coinciding with the index line is noted, which is called OBSERVED HEAD SCALE
READING n’. If the given screw gauge has ZERO ERROR (x) the correction is made
by adding or subtracting the ZERO ERROR (x) from the OBSERVED HEAD
SCALE READING n’.The corrected value (n’-x) or (n’+x) is called the HEAD
SCALE READING (H.S.R) n.

To calculate the fraction, the H.S.R (n) is multiplied by the least count (L.C).

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Thickness of the Glass plate = Total reading = P.S.R + n * L.C ---------- (1)

Changing the position of glass plate, 5 readings should be taken, and recorded in the
table-1. Every time calculate the total thickness of the glass plate using equation (1).

Average of the 5 readings of the glass plate should be calculated, to get the average
thickness (t) of the given glass plate.

b) DETERMINE THE RADIUS(R) OF THE GIVEN METAL WIRE:

The given object metal wire is held between the two parallel surfaces of fix stud S1
and screw tip S2. Note the completed number of divisions on pitch scale, which is
called PITCH SCALE READING (P.S.R). The number of the head scale division
coinciding with the index line is noted, which is called OBSERVED HEAD SCALE
READING n’. If the given screw gauge has ZERO ERROR (x) the correction is made
by adding or subtracting the ZERO ERROR (x) from the OBSERVED HEAD
SCALE READING n’. The corrected value (n’-x) or (n’+x) is called the HEAD
SCALE READING (H.S.R) n.

To calculate the fraction, the H.S.R (n) is multiplied by the least count (L.C).

Diameter of the given wire = Total reading = P.S.R + n * L.C

Changing the position of metal wire, 5 readings should be taken, and recorded in the
table-2. Every time calculate the total diameter (d) of the metal wire using equation
(1).

Average of the 5 diameter of the metal wire should be calculated, to get the average
diameter (d) of the given metal wire.

Radius (r) of the metal wire =𝑑 mm.

2

OBSERVATIONS

i) Zero error =

ii) Zero correction = mm

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iii) Distance moved by the head for 5 complete revolutions = mm

iv) Number of head scale divisions =

𝐷𝐼𝑆𝑇𝐴𝑁𝐶𝐸 𝑀𝑂𝑉𝐸𝐷 𝐵𝑌 𝑆𝐿𝑂𝑃𝐸𝐷 𝐸𝐷𝐺𝐸 𝑂𝑉𝐸𝑅 𝑇𝐻𝐸 𝑃𝐼𝑇𝐶𝐻 𝑆𝐶𝐴𝐿𝐸

v) Pitch of the screw =
𝑁𝑈𝑀𝐵𝐸𝑅 𝑂𝐹 𝑅𝑂𝑇𝐴𝑇𝐼𝑂𝑁𝑆 𝑂𝐹 𝑇𝐻𝐸 𝑆𝐶𝑅𝐸𝑊

𝑃𝐼𝑇𝐶𝐻 𝑂𝐹 𝑇𝐻𝐸 𝑆𝐶𝑅𝐸𝑊

vi) Least count (L.C) =
𝑁𝑈𝑀𝐵𝐸𝑅 𝑂𝐹 𝐷𝐼𝑉𝐼𝑆𝐼𝑂𝑁𝑆 𝑂𝑁 𝐻𝐸𝐴𝐷 𝑆𝐶𝐴𝐿𝐸

TABLE -1

(THICKNESS OF GLASS PLATE)

Pitch Observed Correction ( Corrected Fraction b=n*L. Total

Scale H.S.R (n x) H.S.R n=n C reading (a+
S.N Readin ’) ’-x b) mm
o g
(P.S.R)
am

1.

2.

3.

4.

5.

Average thickness of the glass plate (t) = mm

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TABLE – 2

(DIAMETER OF THE METAL WIRE)

Pitch Observed Correction ( Corrected H.S Fraction b=n* Total

Scale H.S.R (n x) .R n=n’-x L.C reading (a+
S.N Readin ’) b) mm
o g
(P.S.R
) amm

1.

2.

3.

4.

5.

Average diameter d = mm

Average radius r = = mm.

COMMENTS

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 EXPERIMENT # 1
OBJECTIVE

To make different shape products of Plastic (PVC) using hand Injection molding
machine and different dies.

APPARATUS

Hand operated injection molding machine, PVC granules, and die of desired shape,
etc.

PROCEDURE

1) Adjust the die at the base of the machine accurately.

2) Pour the PVC granules into the Hooper.
3) Allow granules remain in the heater until they melt and then push them into the
cavity of the die with the help of handle.
4) Make sure that the die is filled completely with that melted PVC, and then pull
that handle to remove the force.

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5) Detach the die and allow it to cool for some time.

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PROCEDURE

6) Adjust the die at the base of the machine accurately.

7) Pour the PVC granules into the Hooper.
8) Allow granules remain in the heater until they melt and then push them into the
cavity of the die with the help of handle.
9) Make sure that the die is filled completely with that melted PVC, and then pull
that handle to remove the force.

10) Detach the die and allow it to cool for some time.

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 11) When plastic becomes solid, open that dies carefully and take your desired
shape product of plastic (PVC).

COMMENTS
After performing this experiment, we are able to use the injection molding machine
and different types of dies and also know about the different types of PVC.

PVC comes in two basic forms: rigid and flexible. The rigid form of PVC is used in

construction for pipe and in profile.

EXPERIMENT # 2
OBJECTIVE

To join two or more metals by melting a filler metal (solder)

APPARATUS

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Solder iron, solder wire (filler), solder paste, damp sponge, solder stand, etc.

22
THEORY

Soldering is a process in which two or more metal items are joined together by melting
and flowing a filler metal solder into the joint, the filler metal having a lower melting
point than the work piece. Soldering differs from welding in that soldering does not
involve melting the work pieces.

In soldering solder fills the joint by capillary action between closely fitted or closely
placed components.

SOLDERS
Solders are usually tin –lead alloys in various proportions. Because of toxicity of the
Lead and its adverse effects on environment, lead free solders are continually being

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developed and used. These solders are essentially tin-based solders, typical
compositions being 96.5% Sn, 3.5% Ag and 42% Sn, 58% Bi.

PROCEDURE

1) Place the soldering iron in its stand and plug in. The iron will take a few minutes
to reach its operating temperature of about 400°C.
2) Wait a few minutes for the soldering iron to warm up. You can check if it is
ready by trying to melt a little solder on the tip.
3) Wipe the tip of the iron on the damp sponge. This will clean the tip.
4) Melt a little solder on the tip of the iron. This is called 'tinning' and it will help
the heat to flow from the iron's tip to the joint.
5) Hold the soldering iron like a pen, near the base of the handle. Imagine you are
going to write your name! Remember to never touch the hot element or tip.
6) Touch the soldering iron onto the joint to be made. Make sure it touches both
the component lead and the track.
7) Hold the tip there for a few seconds and feed a little solder onto the joint. Apply
the solder to the joint, not the iron. Remove the solder, then the iron, while
keeping the joint still.

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COMMENTS
After performing this experiment, we are able to know about the soldering process
and capillary action and the procedure of joining two or more metals by the help of
solder materials.

INTRODUCTION TO WELDING PROCESS

Solid materials need to be joined together in order that they may be fabricated into
useful shapes for various applications such as industrial, commercial, domestic, art
ware and other uses. Depending on the material and the application, different joining
processes are adopted such as, mechanical (bolts, rivets etc.), chemical (adhesive) or
thermal (welding, brazing or soldering). Thermal processes are extensively used for
joining of most common engineering materials, namely, metals. This exercise is
designed to demonstrate specifically: gas welding, arc welding, resistance welding,
brazing.

WELDING PROCESSES

Welding is a process in which two materials, usually metals, and is permanently joined
together by coalescence, resulting from temperature, pressure, and metallurgical
conditions. The particular combination of temperature and pressure can range from high
temperature with no pressure to high pressure with any increase in temperature. Thus,
welding can be achieved under a wide variety of conditions and numerous welding
processes have been developed and are routinely used in manufacturing.
To obtain coalescence between two metals following requirements need to be met:
• Perfectly smooth, flat or matching surfaces
• Clean surfaces, free from oxides, absorbed gases, grease and other
contaminants
• Metals with no internal impurities. These are difficult conditions to obtain.
Surface roughness is overcome by pressure or by melting two surfaces so that
fusion occurs. Contaminants are removed by mechanical or chemical cleaning
prior to welding or by causing sufficient metal flow along the interface so that
they are removed away from the weld zone friction welding is a solid state

25
 welding technique. In many processes the contaminants are removed by fluxing
agents.
The production of quality welds requires
• A satisfactory heat and/or pressure source
• A means of protecting or cleaning the metal
• Caution to avoid, or compensate for, harmful metallurgical effects.

ARC WELDING

In this process a joint is established by fusing the material near the region of joint by
means of an electric arc struck between the material to be joined and an electrode. A
high current low voltage electric power supply generates an arc of intense heat reaching
a temperature of approximately 3800oC. The electrode held externally may act as a filler
rod or it is fed independently of the electrode. Due to higher levels of heat input, joints
in thicker materials can be obtained by the arc welding process. It is extensively used
in a variety of structural applications.
There are so many types of the basic arc welding process such as shielded metal arc
welding.

WELDING TECHNIQUE

Successful MMA welding depends on the following factors:

1. Selection of the correct electrode
2. Selection of the correct size of the electrode for the job
3. Correct welding current
4. Correct arc length
5. Correct angle of electrode to work
6. Correct travel speed
7. Correct preparation of work to be welded.

ELECTRODE SELECTION

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As a general rule, the selection of an electrode is straight forward, In that it is only a
matter of selecting an electrode of similar Composition to the parent metal. However,
for some metals there is a choice of several electrodes, each of which has particular
Properties to suit specific classes of work. Often, one electrode in the group will be
more suitable for general applications due to its all-round qualities. The table below
shows just a few of the wide range of electrodes, with their typical areas of application.
For example, the average welder will carry out most fabrication using mild steel and
for this material has a choice of various standard electrodes.

ELECTRODE SIZE

The size of the electrode generally depends on the thickness of the section being
welded, and the thicker the section the larger the Electrode required. In the case of light
sheet, the electrode size used is generally slightly larger than the work being welded.

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This means that, if 2.0 mm sheet is being welded, 2.5 mm diameter electrode is the
recommended size. The following table gives the maximum size of electrodes that may
be used for various thicknesses of section.

RECOMMENDED ELECTRODE SIZES

ELECTRODE ANGLE

The angle that the electrode makes with the work is important to ensure a smooth,
even transfer of metal.
The recommended angles for use in the various welding positions are covered later.

CORRECT TRAVEL SPEED

The electrode should be moved along in the direction of the joint being welded at a
speed that will give the size of run required. At the same time, the electrode is fed
downwards to keep the correct arc length at all times. As a guide for general
applications, the table below gives recommended run lengths for the down hand
position. Correct travel speed for normal welding applications varies between
approximately 100 and 300 mm per minute, depending on electrode size, size of run
required and the amperage used.
Excessive travel speeds lead to poor fusion, lack of penetration etc, while too slow a
rate of travel will frequently lead to arc instability, slag inclusions and poor mechanical
properties.

28
WELDING CURRENT

Correct current selection for a particular job is an important factor in arc welding.
With the current set too low, difficulty is experienced in striking and maintaining a
stable arc. The electrode tends to stick to the work, penetration is poor and beads with
a distinct rounded profile will be deposited. Excessive current is accompanied by
overheating of the electrode.

It will cause undercut and burning through of the material, and will give excessive
spatter. Normal current for a particular job may be considered as the maximum, which
can be used without burning through the work, over-heating the electrode or
producing a rough spattered surface (i.e. the current in the middle of the range
specified on the electrode package is considered to be the optimum).
In the case, of welding machines with separate terminals for different size electrodes,
ensure that the welding lead is connected to the correct terminal for the size electrode
being used. When using machines with adjustable current, set on the current range
specified. The limits of this range should not normally be exceeded. The following
table shows the current ranges generally recommended.

GENERALLY RECOMMENDED CURRENT

29
 EXPERIMENT # 3a

OBJECTIVE
To generate an arc and create a weld bead

APPARATUS
Gloves, safety helmet, 250 amp welding machine, hammer and cleaner, work piece,
electrode, etc.

PROCEDURE

Welding is more than dragging a welding rod across a piece of steel and gluing it to
another one. The process begins with properly fitting and securing the work pieces, or

30
metal to be welded, together. For thicker pieces, you may want to grind a bevel so
subsequent beads can be placed in the groove to fill it completely with a solid weld.
Here are the basic steps for completing a simple weld.

1) Strike the arc. This is the process of creating an electric arc between the
electrode and the work piece. If the electrode simply allows the current to pass
directly into the grounded work piece, there will not be enough heat produced
to melt and fuse metal together.
2) Move the arc to create a bead. The bead is the metal from the melting electrode
flowing together with molten metal from the base metal to fill the space between
the pieces being joined by welding.
3) Shape the weld bead. This is done by weaving the arc back and forth across the
weld path either in a zig zag or in motion so the metal spreads to the width that
you want your finished weld bead to be.
4) Chip and brush the weld between passes. Each time you complete a pass, or trip
from one end to the other of your weld, you need to remove the slag, or the
melted electrode flux material, from the surface of the weld bead so only clean
molten metal will be filling the weld on the subsequent pass.

COMMENTS
After performing this experiment, we came to know about the weld bend by generating
an arc and also know about the safety precautions. We also get to know about the
working of 250amp welding machine and its different uses in daily life.

31
 EXPERIMENT # 3b
OBJECTIVE
To perform the arc welding process to join two plates using electrode and welding
machine (Butt Joint).

APPARATUS
Gloves, safety helmet, 250 amp welding machine, hammer and cleaner, work piece,
electrode, etc.

32
PROCEDURE

Before you start to weld, ensure that you have all the required equipment and
accessories. Listed below are some additional welding rules that should be followed.
1) Clear the welding area of all debris and clutter.
2) Do not use gloves or clothing that contains oil or grease.
3) Check that all wiring and cables are installed properly.
4) Ensure that the machine is grounded and dry.
5) Follow all manufacturers’ directions on operating the welding machine.
6) Have on hand a protective screen to protect others in the welding area from
FLASH bums.
7) Always keep fire-fighting equipment on hand.

First of all, place the plates at a suitable place and clean them to perform welding
process. Wear the safety helmet and gloves. Hold the consumable electrode at one end.

33
In this Method we use, Electric Arc welding process which is based on providing an
electric circuit comprising the Electric current source the feed and return path, the
electrode and the work piece. The arc welding process involves the creation of a
suitable small gap between the electrode and the work piece. When the circuit is made
a large current flows and an arc is formed between the electrode and the work piece.
The resulting high temperature causes the work piece and the electrode to melt. Hence
we can join two plates easily. When the weld solidifies a crust is formed from the
impurities created in the weld process (Slag). This is easily chipped away.

COMMENTS
In this experiment we know about the different types of joints we can produce by
using arc welding process and also know about the safety precautions we adopt.

EXPERIMENT 3c
OBJECTIVE
To perform the arc welding process to join two metals using electrode and welding
machine (T joint).

APPARATUS
Gloves, safety helmet, 250 amp welding machine, hammer and cleaner, work piece,
electrode, etc.

34
PROCEDURE

1) Place the material at a suitable place and clean them to perform welding process.
2) Hold the consumable electrode at one end.
3) In this Method we use, Electric Arc welding process which is based on
providing an electric circuit comprising the Electric current source the feed and
return path, the electrode and the work piece.
4) The arc welding process involves the creation of a suitable small gap between
the electrode and the work piece.
5) When the circuit is made a large current flows and an arc is formed between the
electrode and the work piece.
6) The resulting high temperatures causing the work piece and the electrode to
melt. Hence we can join two pipes easily.
7) When the weld solidifies a crust is formed from the impurities created in the
weld process (Slag).
8) This is easily chipped away.
PRECAUTIONS

Before you start to weld, ensure that you have all the required equipment and
accessories. Listed below are some additional welding rules that should be followed.

35
 • Clear the welding area of all debris and clutter.
• Do not use gloves or clothing that contains oil or grease.
• Check that all wiring and cables are installed properly.
• Ensure that the machine is grounded and dry.
• Follow all manufacturers’ directions on operating the welding machine.
• Have on hand a protective screen to protect others in the welding area from
FLASH bums.
• Always keep fire-fighting equipment on hand.

COMMENTS
After performing this experiment, we know about the process to make the T
joint between two metals by using arc welding process and also know about the
safety precautions.

EXPERIMENT 3d
OBJECTIVE
To perform the arc welding process to make a metallic box

APPARATUS
Gloves, safety helmet, 250 amp welding machine, hammer and cleaner, work piece,
electrode, etc.

36
PROCEDURE

Before you start to weld, ensure that you have all the required equipment and
accessories. Listed below are some additional welding rules that should be followed.
1) Clear the welding area of all debris and clutter.
2) Do not use gloves or clothing that contains oil or grease.

3) Check that all wiring and cables are installed properly.

4) Ensure that the machine is grounded and dry.
5) Cut the materials according to drawing
6) Follow all manufacturers’ directions on operating the welding machine.
7) Have on hand a protective screen to protect others in the welding area from
FLASH bums.
8) Always keep fire-fighting equipment on hand.

COMMENTS
In this experiment we get to know about the procedure to make the metallic box with
the help of using arc welding process and also know about the safety precautions. We
also came to know about the different procedure we adopt to make metallic box rather
than arc welding process.

37
 EXPERIMENT # 4
OBJECTIVE
To perform a sheet metal cutting process using power press.

38
APPARATUS
Power Press, Metal Sheet

THEORY

A Power press is a machine that houses the stamping tools (tooling) and carries them
around according to the kinematics indicated by the user (process set-up). The
39
knowledge of the press used for a stamping operation provides us with useful clues
regarding:

• Value and distribution of restraining forces

• Tool deformation caused by stamping forces
• Contact and/or gap between tools and blank

PROCEDURE

A sheet formed part is usually obtained through a number of operation (phases)

Each operation can be decomposed in several phases. It may be necessary to

model each of them

1) Gravity fall
2) Holding
3) Forming
4) Trimming, flanging
5) Spring back

Most problems in sheet metal forming come from a bad control of holding,
restraining and spring back.
GRAVITY FALL
The blank adapts to the blank holder shape
HOLDING
The die pushes on the blank holder and squeezes the blank.
Holding controls, the shape of the blank and the contact between the blank and the
punch.

FORMING
The die goes down until it squeezes the blank onto the punch.
The forming operation can in turn be divided in two parts:

40
 • First the volume of the part is created. This is mostly controlled by the
production surface and by the restraining system

• Last the geometry details are formed. This is controlled by the geometry of the
part

TRIMMING AND SPRING-BACK

Plastic deformation leaves some stresses locked through metal thickness. After the
extraction from the tools these stresses are released originating a different shape than
that of the tools. Spring-back before trimming is sometimes important for the design
of the tools and robots of the press.
Spring-back after trimming may change the shape of the part to the point that it is
impossible to assemble.

COMMENTS
After performing this experiment, we came to know about the gravity fall, holding
and forming in detail and also know about the working of power press and procedure
to cut the metal sheet by using power press.

EXPERIMENT # 5

41
OBJECTIVE
To prepare horizontal surfaces, vertical surfaces and slots using a shaper.

APPARATUS
Shaping tool, Mild steel, work piece, Steel rule, vernier caliper, try square
PROCEDURE

1) Cut a flat piece of required dimensions with the help of hack saw.

42
 2) Fix the shaping tool on shaper appropriately.
3) Fix the job in the vice of shaping machine.
4) Machine the top surface first
5) Invert the job surface and machine the remaining surfaces in a sequence.
6) Mark the piece for making the groove.
7) Make the groove according the marking.

PRECAUTIONS
• Work piece should be firmly gripped in the vice.
• Use the machine at low speeds.
• Hand gloves, apron and shoes must be used while working.

WORK PIECE DIMENSIONS

Remove 2mm from all sides

COMMENTS
After performing this experiment, we know about the working of shaper machine and
to prepare the horizontal, vertical and slots in different metals of their given
dimension by using shaper machine.

43
 EXPERIMENT # 6

OBJECTIVE
To smooth the surface of a work piece using surface grinder

APPARATUS
Surface grinder, work piece of metal, vernier calipers, steel rule.etc

44
THEORY
Surface grinding is used to produce a smooth finish on flat surfaces. It is a widely used
abrasive machining process in which a spinning wheel covered in rough particles
(grinding wheel) cuts chips of metallic or non-metallic substance from a work piece,
making a face of it flat or smooth.

PROCEDURE

1) Adjust the height valve, located on the grinder head, so that the grinder blade is
as far from the magnetized palette as possible.
2) Place the work piece on the magnetized palette.
3) Toggle the palette lever, located near the control panel and typically marked by
a red dot. This will magnetize the palette and keep your metal block from
moving.
4) Readjust the grinder height so that it is approximately 2 inches from the surface
of the metal block. You do not want to start the grinder when it is touching the
metal block, as the grinder wheel could be damaged as it starts to spin.
5) Activate the grinder. This is typically done by turning the ignition key, then
pressing the green or red colored start button. The grinder will begin spinning
and lower itself in a pre-set back-and-forth pattern, rotating a half-inch back and
forth until it makes contact with the surface of metal block

6) Watch the surface of the metal. If you leave the block in place , the grinder will
eventually grind it to dust.

COMMENTS
In this experiment we get to know about the working of surface grinder and know
about the different parts of surface grinder. We also get to know about the procedure to
smooth the different materials or metals by using surface grinder.

45
 EXPERIMENT # 7

OBJECTIVE

To make a spur gear on horizontal milling machine

APPARATUS

46
Milling Machine, Steel rule, Vernier Calipers with depth gauge, Mild steel work piece,
Side and face milling cutter.

PROCEDURE
1) Work piece of metal as per required dimension is cut on power hacksaw.
2) Required dimension is marked on the work piece using try square and Scriber.
3) Side and face milling cutter is fixed in the arbor appropriately.
4) The job is fixed in vice of milling machine.
5) The side milling from all four sides of the job is done using small cuts till marking is
achieved.
6) The piece is marked for maintaining the height.

7) The top surface is milled till the required height is achieved

47
PRECAUTIONS
1) Work piece should be firmly gripped in the vice.
2) Coolant is to be used where required.
3) Do not try to over speed the machine.
4) Hand gloves, apron and appropriate shoes are recommended.

COMMENTS

After performing this experiment, we get to know about the different types of gear
and the working of horizontal milling machine. We also get to know about the
procedure to make the spur gear by using horizontal milling machine.

EXPERIMENT # 8a
OBJECTIVE

48
To make a hexagonal shape on vertical milling machine

APPARATUS
Vernier calipers, vertical milling machine, drill, Teflon.

PROCEDURE

49
1) Prepare the work piece and hold the work piece in the vice of vertical milling
machine then check the center of the tool by taking the tool or moving the work
piece exactly below the cut.
2) Turn on the machine and start the machining process. Feed the work piece
manually when it passes the drill.
3) Operate the machine carefully to make a required diameter of the specimen.
4) Cutting should be done on both side of the work piece.
5) After finishing the job, loose the jaw of vice and take out the work piece and clean
the machine.
COMMENTS
In this experiment we get to know about the working of vertical milling machine and
also know about the different shapes we can make of the material by using vertical
milling machine. We also know about the procedure to make the hexagonal shape of
material by using vertical milling machine.

50
 EXPERIMENT # 8b

OBJECTIVE
To perform circular machining using rotary table on milling machine.

APPARATUS
Vernier calipers, vertical milling machine, drill, Teflon.

51
DESCRIPTION
The Rotary Table
• Circular milling attachment
• Used on plain universal vertical milling machines and slotters
• Provide rotary motion to work piece
• Cut radii, circular grooves and circular sections
• Two types

52
 – hand feed and power feed

Rotary Table Construction

• Base bolted to milling machine table

• Rotary table fits into base
• Worm gear on bottom of rotary table
• Worm shaft mounted in base and meshes with and drives worm gear
• Hand wheel mounted on outer end of worm shaft
– Vernier scale on collar permits setting to within 2 minutes of a degree

PROCEDURE

a) To Center Rotary Table with Vertical Mill Spindle

1. Square vertical head with machine table

2. Mount rotary table on milling machine
3. Place test plug in center hole
4. Mount indicator with grasshopper leg in machine spindle
5. With indicator just clearing top of test plug, rotate machine spindle by hand
align plug with spindle
6. Bring indicator into contact with diameter of plug and rotate spindle
7. Adjust machine table by longitudinal and crossfeed handles until dial indicator
registers no movement
8. Lock machine table and saddle, recheck alignment
9. Readjust if necessary

b) Method to Center Work piece on Rotary Table

1. Align rotary table with vertical head spindle

2. Lightly clamp work piece to rotary table in approximate center
3. Disengage rotary table worm mechanism
4. Mount indicator in machine spindle or on milling machine table

53
 5. Bring indicator into contact with surface to be indicated and revolve rotary
table by hand
6. With soft metal bar, tap work until no movement registered on indicator in
complete revolution of table
7. Clamp work piece tightly and recheck accuracy of setup

c) Radius Milling Procedure

1. Align vertical milling machine spindle at 90º to table

2. Mount circular milling attachment
3. Center rotary table with machine spindle
4. Set longitudinal feed dials and cross feed dial to zero
5. Mount work on rotary table
6. Move either cross feed or longitudinal feed an amount equal to radius required
7. Lock both table and saddle
8. Mount proper end mill
9. Rotate work to starting point of cut
10. Set depth of cut and machine slot to size

COMMENTS
In this experiment we get to know about the circular machining using rotary table on
vertical milling machine and its different parts. The milling machine has got the cutter
installed up on it which helps in removing the material from the surface of the work
piece. Its advantages are that it provides flexible computer control options for cutting
purposes and allows us to make a cut in any orientation which aids us in circular
machining by the help rotary table.

54
 EXPERIMENT # 8c

OBJECTIVE
To perform different surface machining process using shell End Mill cutters

APPARATUS
Vernier calipers, vertical milling machine, drill, Teflon.

PROCEDURE

55
 1) Prepare the work piece and hold the work piece in the bed of milling
machine using clamp for fixation.
2) Shell Cutter is attached to the Toll head is attached to the shell cutter is set
in the tapered portion of the spindle and tight it through the rod available
in tool box.
3) Now turn on the machine and start the machining process. Feed the work
piece manually.
4) The bed moves from left to right as the shell end cutter moves in clock wise
direction.
5) There is also an adjustment such that the tool moves and the milling bed
remains fixed.
6) After finishing the job, loose spindle and take out tool.
7) The work piece is removed from the milling bed.

COMMENTS
In this experiment we get to know about the different surface machining process using
shell End Mill cutters. A shell mill is any of various milling cutters whose construction
takes a modular form, with the shank made separately from the body of the cutter,
which is called a "shell". By using this process, we were able to do multiple process
such as machining process and cutting processes etc. on the work piece.

56
 EXPERIMENT # 9

OBJECTIVE

To do facing and straight turning on job after job centering and tool centering using lathe
machine.

APPARATUS

57
Single point cutting tool, parting tool, drill bits, drill chuck , Mild steel rod, Steel rule,
vernier caliper, sine bar.

PROCEDURE

Job is fixed in three jaw chuck for proper job centering.

1) Single point cutting tool is fixed in the tool post after tool centering and

facing operation is completed.

2) A rough cut is used to turn the outer periphery.

3) Final turning and step turning operation is completed in sequence.

4) The compound slide is set at the taper angle as per calculation with the center line

58
 and tapering operation is completed through different cuts.

5) Radius tool is fixed in tool post for making radius and operation is completed.

6) For maintaining the proper length of the job parting off tool is used and parting
operation is completed.

COMMENTS

In this experiment we get to know about the working of lathe machine and its different
parts and also know about the facing and turning process performs on work piece. A lathe
is a machine tool that rotates a work piece about an axis of rotation to perform
various operations such as cutting, sanding, knurling, drilling etc.

EXPERIMENT # 9b

OBJECTIVE

To do taper turning using compound slide on the same job as done in experiment no 15.
APPARATUS

59
Single point cutting tool, parting tool, drill bits, drill chuck, Mild steel rod, Steel rule,
vernier caliper, sine bar.

PROCEDURE

The Compound Slide Method

60
The compound slide is set to travel at half of the taper angle. The tool is then fed across
the work by hand, cutting the taper as it goes.

1) Job is fixed in three jaw chuck for proper job centering.

2) Single point cutting tool is fixed in the tool post after tool centering

3) The compound slide is set at the taper angle as per calculation with the center line
and tapering operation is completed through different cuts.

COMMENTS

In this experiment we get to know about the another process we can perform on lathe
machine that is taper turning using compound slide. The process of taper turning can
also be done by the aid of the lathe machine as it is a multiple job preforming machine
and it was able to complete the task with ease and accuracy.

61
 EXPERIMENT # 10

OBJECTIVE
Introduction of CNC wire cut EDM.

WORKING AND PRINCIPLE

Wire Cut EDM works on the principle of Electrical Discharge Wire Cutting (EDWC),
most commonly known as Wire Cut EDM. It is a spark erosion procedure to produce
complex 2-Dimentional and 3-Dimentional shapes through electrically conductive
work pieces. This machine is used only for manufacture parts which are electrically
conductive. Wire Cut EDM differs from conventional EDM is that a thin, 0.05-0.3 mm
in diameter wire used for manufacturing of our product. The wire wound around a
spool, feeds through the work piece and is takes upon two section spool. A D.C. power
supply device, high frequency pulses of electricity required for wire and work piece to
get required process using discharge of electron. This can be achieved with the help of
gap which is provided in between wire and work piece so the electric discharge occurs
and metal removing process done by the use of which we have produce required
produce on the Wire Cut EDM.With Wire Cut EDM technique complicated cutting
process can be achieved very easily as compare to either our conventional
manufacturing process or use of high cost and very precise manufacturing machine
which are very expensive. The high degree of accuracy obtainable and the fine surface
finish is also achieved with the help of this machine. Finishes make Wire Cut EDM
particular valuable for the applications of involving the material of press stamping dies,
extrusion dies, prototype parts and excess the fabrication of conventional EDM
electrode.

62
 Fig-1: -Schematic Diagram of Wire Cut EDM

TECHNICAL SPECIFICATIONS FOR WIRE-CUT EDM

CONTROL PANEL EZ-01

▪ Control Mode : CNC close loop

▪ Simultaneously Controlled Axis : X, Y, U, V.
▪ Control Panel Size : 550 X 800 X 1830 mm.
▪ Control Panel Weight : 175 kg.
▪ Input Program Format : G code
▪ Display : 15”color CRT
▪ Minimum Input Command : 0.001 mm.
▪ Minimum Increment : 0.001 mm.
▪ Interpolation Function : Linear, Circular
▪ Power Requirement : 415V / 50Hz / 3ph / 1.5Kva max.

63
 MACHINE TOOL
▪ X, Y axis travel : 250 X 320 mm.
▪ Maximum work piece size : 450 X 300 mm.
▪ Max thickness Machineable : 140 / 200 / 400 mm.
▪ Max work piece weight : 120 kg.
▪ Max taper cutting angle : 3 degrees at 100 mm job height
▪ Machine Tool Size (L x W x H) : 1400 X 700 X 1700 mm.
▪ Machine Tool Weight : 800 kg.
▪ Wire Diameter : 0.15-0.25 mm. (0.25 mm. std.)
▪ Best Surface Finish (Ra) : <= 3 µm.
▪ Max Cutting Speed : 50 mm/min.
▪ Max Dry Run Speed : 25 mm/min.
▪ Table Movement Using Pendent Unit : 120 mm/min.
▪ Heat Affected Zone : 10 µm.

MAIN FEATURES OF WIRE CUT EDM

1) The highly precise machine tool includes high precision ball screw, ceramic
rolling guide, high-speed wire-feed mechanism and diamond guides.
2) Tension controllable wire driving system keeps constant wire tension.
3) Complicated profiles can be generated on IBM compatible PC. Manual
programming can be done for simple programs and it can be directly entered
using keyboard.
4) Automatic center-find, edge find, pause at wire breaks, pause at short circuit,
program can be restarted after power failure from the same point where power
was interrupted.
5) X, Y, U, V, table displacement and the figure displayed on CRT screen.
6) Automatic stop after end of jobs.
7) Automatic wire radius compensation ensures work-pieces accuracy.
8) Unique Features: Wire is reused which drastically reduces machining cost.

64
WIRE LOAD PROCEDURE

1) Move wire drum assembly towards right so that LHS sensor gets operated. Load
wire as shown in figure.
2) Fix one end of wire (start) on wire drum.
3) Set wire feed speed to minimum.
4) Make wire feed motor ON and slowly increase wire feed speed so as to run wire
feed motor at lower speed.
5) Observe wire gets wound evenly on a wire drum.
6) Make wire feed motor off as soon as RHS sensor gets operated.
7) Fix another end of wire (end) on wire drum.
8) Move both sensing strips inside by approximately 5 mm.

Start
LHS

Wire Drum Wire Spool Wire Drum Wire Path Wire Brk Sensor

Fig-2: - Wire Load Procedure

KEYBOARDS AND CONTROL PANEL DESCRIPTION

KEYS

a) ‘F1’ – CNT FND: Used for center finding operation. Wire must be threaded
through hole/cavity for which center find operation is to be performed.
b) ‘F2’ – EDG FND: Used for edge finding operation. Wire must be loaded before
performing this operation. Press F2 and then arrow keys or pendent keys to move

65
 table in that direction. Edge find operation can terminate whenever gap short
condition is detected.
c) ‘F3’ – BCK ORG: Returns back to origin through shortest path. Use this key when
‘spark’ is inactive and it is necessary to return to start point of current program.
d) ‘F4’ – WBRK BN: Wire break sensor enable key. If selected wire feed motor
turned off when wire break gets detected.
e) ‘F5’ – DRY RUN: Use this key for dry run operation. File must be loaded before
performing this operation. Use + or – keys for increasing or decreasing dry run
speed.
f) ‘F6’ – GAPSHT RETRACE: Use this key to retrace maximum 200 steps if gap
short occurred in spark mode. If gap short is not recovered within 200 steps there
must be some other problem and back to origin operation must be performed after
removing wire.
g) ‘F7’ – No BUZZ: If selected will not sound.
h) ‘F8’ – ROTATE: Select ROTATE operation and use +/- keys to rotate selected
profile by +/-90 degrees.
i) ‘F9’ – DRO: if selected X, Y, U, V co-ordinate can manually updated. Disable in
spark and dry run mode.
j) ‘F10’ – BLK STP: If block step is selected machine will pause after execution of
each block. Effective in spark and dry run operation.
k) ‘Alt-F’: Used for loading new file.
l) ‘R’: Press for resetting sparking time (SPRK TIMG) to 0. Disable in spark mode.
m) ‘F’: Press of altering wire feed speed.
n) ‘G’: Press for altering gap voltage setting.
o) ‘L’: Press for altering pulse setting. Set pulse position 1 for finishing and 4 for
speed.
p) ‘S’: Press for making spark On/Off.
q) ‘P’: Press for making coolant pump On/Off.
r) ‘W’: Press for making wire feed motor On/Off.
s) ‘Alt-W’: Used for wire vertically adjustment. First press Alt-W and then arrow
keys to move U/V motor for wire vertically. Key other than arrow keys exit this
mode.
t) ‘Alt-X’: Exit from Execute menu/screen and come to command prompt
INTERLOCK
66
 1) WIRE BREAK: Indicates wire break condition. If wire break sensor is enabled
wire break condition turn off wire feed rotor.
2) GAP SHORT: Indicates gap short condition.
3) TABLE LIMIT: Indicates table limit switch is operated. Spark or dry run mode
aborted if table limit inter lock glows. Table movement is possible only using
pendent unit.

INDICATORS

TRIP: Indicates machine trip condition. Check for one of the following:-

1) Check input three phase voltages. Over-voltage or Under-voltage condition trip the
machine.
2) Emergency Off switches on front panel trips the machine.
3) Mechanical limit switch for wire feed motor assembly trips the machine. This
condition occurs if wire feed direction control sensors fails to operate.

TAPER CUTTING USING WIRE CUT EDM

UPPER WIRE GUIDE C1

JOB
D1

D2
LOWER WIRE GUIDE C2

JOB STAND

Fig-3:- Schematic Diagram Of Upper & Lower Guide With Job Stand

1. Z axis position (Z): Reading on Z axis scale during machining.

67
 2. Guide Span: (Ref. Fig.) It is calculated by formula,
GUIDE SPAN = D1+C1+C2-Z

Where, Z is reading on Z axis scale.

3. Work Table Height: It is distance between lower wire guide and bottom
surface of work piece i.e. Work table height= D2+C2
Here C is distance between edge of the wire and diamond hole. For this value
ref. the value written on the guide or machine file.

4. Additional Work Table Height (Program Height): Distance between bottom

surface of the work piece and the plane at work piece on which programmed
profile is desired

• Initial values of guide span and work table height pasted inside back door of panel

H
h

Fig-4: - Taper Cutting

TAPER G52(RIGHT) G51(LEFT) G52(RIGHT)

G51(LEFT)
ADDITIONAL
WORKTABLE H 0 H-h h
HEIGHT
DIRECTION OF MOTION IS CONSIDERED AS CLOCKWISE
OBSERVATIONS

• Work piece material-………….

68
 • Work piece size-………………
• Voltage-………..
• Current-………..
• Pulse rate-………
• Wire diameter-………
• Cutting speed-………..

COMMENTS
In this experiment we get to know about the Electrical Discharge Machining (EDM)
that is a controlled metal-removal process that is used to remove metal by means of
electric spark erosion. In this process an electric spark is used as the cutting tool to cut
(erode) the work piece to produce the finished part to the desired shape. It is a spark
erosion procedure to produce complex 2-Dimentional and 3-Dimentional shapes
through electrically conductive work pieces. Wire Cut EDM differs from conventional
EDM is that a thin, 0.05-0.3 mm in diameter.

69
 EXPERIMENT # 10b

OBJECTIVE

To prepare a job using EDM Wire Cut machine for external cutting process.

APPARATUS

CNC wire cut machine, Vernier caliper, CNC wire cut tool box dial indicator.

PROCEDURE

1) Use the software for process which is “HF System (V7.03)”.

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 2) After opening the software, a tool bar will be shown.
3) Select “Program” tap.
4) “Clear” screen for new drawing.
5) Select “Read” to load the file.
6) Open the “File of DXF (DXF represent the format)”.
7) Select the drive name i.e. [DXF]I:4.
8) Dialogue box will appear as follows:
a) Call all
b) No read
Select option (1) to process.
9) Program loads and the drawing previews on the main screen.

NOTE: Select full screen for your own convenience.

10) Select “Detrace” (Line or Arc) option for line cut.

11) Go back to the main program. Then lead in outline.
12) Various methods of cutting will be shown.
13) Select “Point Method”.
14) Then give the cut path with the help of pointer i.e.(0,0)
15) Program will ask direction to start. Select “Left”
16) Select “Next” from the program.
17) Offset (mm) will be required. Give the value i.e. 0.12.

(OBJECT PREVIEWS)

18) Select “Next” to proceed.

19) Select the options “2D list of 3B” from the window appeared.
20) Now select “Save list of 3B” to save the file in drive i.e. [.3B]123.(Note:
Overwrite the file if needed.)
21) Then “Exit”.
22) After reaching on the main screen, select “Read” option.
23) Select options “Read 3-B code”
24) Now select the file i.e. 123.3B.
25) The program will be shown.
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 26) To run the program press “+ Cut”.
27) The machine will start cutting.

PRECAUTIONS

1) Cutting oil must be used during the operation.

2) To save the cutting oil during the operation must use cover guards.
3) During the working operation electric voltage must be constant.
4) Do not tough the work piece during the operation.

COMMENTS
In wire electrical discharge machining (WEDM), also known as wire-cut
EDM and wire cutting is fed as the work piece. The work piece was easily
manufactured as the machine was easy and simple to use and did all the work
automatically after the program was entered and run-ed.

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 EXPERIMENT # 10c

OBJECTIVE

To prepare a job using EDM Wire cut machine for internal cutting process.

APPARATUS

CNC wire cut machine, vernier caliper, CNC wire cut tool box dial indicator.

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PROCEDURE

1) Use the software for this process which is “HF System (V7.03)”.
2) After opening the software, a tool bar will be shown.
3) Select “Program” tap.
4) “Clear” screen for new drawing.
5) Select “Read” to load the file.
6) Open the “File of DXF (DXF represent the format)”.
7) Select the drive name i.e. [DXF] I: 4.
8) Dialogue box will appear as follows:
1. Call all
2. No read
Select option (1) to process.
9) Program loads and the drawing previews on the main screen.
NOTE: Select full screen for your own convenience.

10) Select “Detrace” (Line or Arc) option for line cut.

11) Go back to the main program. Then lead in outline.
12) Various methods of cutting will be shown.
13) Select “Point Method”.
14) Then give the cut path with the help of pointer i.e. (0,0)
15) Program will ask direction to start. Select “Left”
16) Select “Next” from the program.
17) Offset (mm) will be required. Give the value i.e.- 0.12.

(OBJECT PREVIEWS)

18) Select “Next” to proceed.

19) Select the options “2D list of 3B” from the window appeared.
20) Now select “Save list of 3B” to save the file in drive i.e. [.3B]123.
(Note: Overwrite the file if needed.)
21) Then “Exit”.
22) After reaching on the main screen, select “Read” option.
23) Select options “Read 3-B code”
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 24) Now select the file i.e. 123.3B.
25) The program will be shown.
26) To run the program press “+ Cut”.
27) The machine will start cutting.

PRECAUTIONS

1) Cutting oil must be used during the operation.

2) To save the cutting oil during the operation must use cover guards.
3) During the working operation electric voltage must be constant.
4) Do not tough the work piece during the operation.

COMMENTS
We can start this process by HF SYSTEM software afterwards We can operate this
machine in the way that we feed it all the commands all of which correspond to the
dimensions that we want as an end product and we start the machine and once started
the machine tends to complete the process on its own.

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 EXPERIMENT # 11

OBJECTIVE

To prepare a job by marking punch and drill holes on the metal sheet using drilling
machine and tapping for internal threading.

APPARATUS

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Drilling machine, Drill chuck. machine vice, hammer, centre punch, hacksaw, drill bits
and tap with tap wrench , Mild steel flat, Steel rule, vernier caliper, scriber.
TABLE FOR TAP DRILL SIZES

METRIC HOLE MINOR HOLE MINOR

THREAD DIA.MIN DIA. MAX

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 M1.6 x 0.35 1.373 1.418
M2.0 x 0.40 1.740 1.792
M2.5 x 0.45 2.210 2.261
M3.0 x 0.50 2.667 2.743
M3.5 x 0.60 3.099 3.200
M4.0 x 0.70 3.556 3.632
M4.5 x 0.75 4.013 4.115
M5.0 x 0.80 4.318 4.470
M6.0 x 1.00 5.156 5.359
M7.0 x 1.00 6.147 6.350
M8.0 x 1.00 7.163 7.341
M8.0 x 1.25 6.934 7.188

PROCEDURE

1) A flat piece of required dimension is to be cut using hacksaw.

2) Both edges are filled and checked for squareness using try square.
3) Chalk solution is applied on the surface of metal and left to dry.

4) Dried metal piece is marked as per dimension given in the drawing using steel rule
and scriber.

5) Centre of the hole is marked using punch and hammer.

6) Job is clamped in the vice of drilling machine keeping the marked surface upward
and enlarges the centre of the hole using centre in the drilling.

7) The centre drill is taken out and the drills of required sizes are fitted in the drill
chuck of the machine and drill the job.

PRECAUTIONS

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 1) Feed to be applied slowly in the beginning.
2) Heavy feed may damage the drill bits. Don’t use too much pressure on the
feed handle.
3) Coolant is to be used.
4) Hand gloves, apron and shoes must be used while working.
5) Work piece should be firmly tightened in the vice of the machine.

COMMENTS
In this experiment we know about the working and use of drill machine that is a machine
tool which is used to drill the work piece. Internal threading is done by using a tool
called a TAP in a hole drilled to a specific diameter for the thread size and pitch you
want to cut. By using the drill machine we can easily draw the hole and by utilizing the
tap to mark the punches on the work piece.

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 EXPERIMENT # 12a

OBJECTIVE

Introduction to CNC Lathe machine and program making for facing and turning

THE VICE

This holds the material to be cut or shaped. Material must be held securely otherwise it
may 'fly' out of the vice when the CNC begins to machine. Normally the vice will be
like a clamp that holds the material in the correct position.

THE GUARD

The guard protects the person using the CNC. When the CNC is machining the material
small pieces can be 'shoot' off the material at high speed. This could be dangerous if a

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piece hit the person operating the machine. The guard completely encloses the the
dangerous areas of the CNC.

THE CHUCK

This holds the material that is to be shaped. The material must be placed in it very
carefully so that when the CNC is working the material is not thrown out at high speed.

THE MOTOR

The motor is enclosed inside the machine. This is the part that rotates the chuck at high
speed.

THE LATHE BED

Base of the machine. Usually a CNC is bolted down so that it cannot move through the
vibration of the machine when it is working.

THE CUTTING TOOL

This is usually made from high quality steel and it is the part that actually cuts the
material to be shaped.

CNC TURNING CENTRES

Turning Centre with increase capacity tool change is also making a strong appearance
in modern production shop. These CNC machines are capable of executing many
different types of lathe cutting operations simultaneously on a rotating part.

TYPES OF PROGRAMMING

1) MANUAL PROGRAMMING
This refers to the act of creating Numerical Control program entirely through “manual
calculations.”

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2) AUTOMATIC PROGRAMMING
As the geometry to be machined get complex like 3D profile, it becomes difficult to
create programs through manual calculations. Such programs are created by the help
of special-purpose computer software.

GENERAL STRUCTURE OF PROGRAM

Here bellow is the definition of each display area under system main screen
(refer to Fig3.2)

1, title bar: the top column shows current date and time

2, program name display area: show the program which will execute or being
running

3, program display area: show the program content which will execute or being
running and also its process.

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 4, feed speed display area: show the instruction speed, override, real speed and
speed ratio of feed axis. “F500”in the column means the speed is 500mm/min;
“100%” behind means real running speed is 500mm/min x 100%

5, spindle speed display area: show current speed, rate, real running speed and
speed ratio of spindle instruction. “S800”in the column means the speed is
800r/min; “100%”behind means the real running speed is 800r/min x 100%.

6, spindle real speed display

7, G00 speed ratio display: in auto mode, the real running speed of G00 is “G00
speed X 100%”
8, Status display: to display system status---auto or manual mode, also
continuous, increment, MPG in manual mode; step, continuous, real machining,
simulation, stop, run status and relevant information in auto mode.

9, M code display: to display M code status

10, tool status display: to display relevant information of tool

11, machined time display: to display executed time of current program

12 coordinate display: dynamic coordinate display, viz. display current selected

coordinates (it may be machine coordinates or work piece coordinates).

13, information display: display information relevant to system, machine. Such

as alarm, soft/hard limit

WORD

A word is the basic instruction unit to command CNC system to complete the control
function, composed of an English letter (called instruction address) and the following
number (operation instruction with/without sign). The instruction address describes

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the meaning of its following operation instruction and there may be different
meaning in the same instruction address when the different words are combined
together. See Table 1-2 words in the system.

G - INSTRCUTIONS
G instruction consists of instruction address G and its following 1 2 bits instruction
value, used for defining the motion mode of tool relative to the work piece, defining
the coordinates and so on.

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APPARATUS
CNC Lathe machine, High speed steel, Vernier caliper, Teflon
PROCEDURE
1) Give the data in digit and alphabet form through the panel of the CNC lathe
machine according to the drawing.
2) Adjust the job on the chuck of CNC machine.
3) Start the machine and enter the program.
4) Center the tool with job by using XZ coordinates in absolute system.
5) Start facing and turning operations on job.
PROGRAM

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COMMENTS
A CNC lathe is typically designed to utilize modern versions of carbide tooling and
processes or by using CNC Simulator. It is an automatic machine which is able to
perform all the all the tasks not only effectively but also with great accuracy. By
entering the commands of facing and turning at specific speeds we can get our desired
results with less effort because of the CNC lathe.

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 EXPERIMENT # 12b
OBJECTIVE
To make a shape of a job by using G02 and G03 codes.

APPARATUS
CNC Lathe machine, High speed single cutting tool, chuck key, Vernier caliper, Teflon.

G02 and G03 Codes

Circular arc interpolation (G02/G03)
Mainly apply in execution of circular arc interpolation cutting on specified flat surface
with G02 (clockwise) or G03 (counterclockwise).
Format：G02 (G03) X (U) - Z (W) - K- I- (R-) F- ; ZX flat surface (Mode)

Explanation

G02/G03 instruct tool to execute circular arc machining in clockwise or

counterclockwise.
We can judge it is G02 or G03 circular arc interpolation According to rotary direction
of interpolation on flat surface. The machining flat surface is the flat which in the face
of observer along Y-axis’ indication. Refer to fig

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 The interpolation direction of G02/G03

G03: counterclockwise circular arc interpolation.

X, Z: in absolute programming, the coordinates value of arc end point in work
coordinates.
U, W: in increment programming, the displacement of arc end point relative to arc
starting point.
I, K: the increment of the center relative to arc starting point( equals to the coordinates
value of center minus the coordinates value of arc starting point, as fig4.13), in absolute
or incremental programming, the two are specified in incremental mode ; in diameter
or radius programming, “I” is radius value .

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R: circular arc radius, when circular arc angle is more than 180 degrees, “R” will be
expressed with negative value.
F: The synthetical feeding speed of two programmed axes
Note: clockwise or counterclockwise is the rotary direction looked from the positive
direction of the coordinates axis of the flat surface perpendicular to the circular arc.

As fig. Shows, use circular arc interpolation instruction to program

Programming example using G02/G03

PROCEDURE

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 1) Give the data in digit and alphabet form through the panel of the CNC lathe
machine according to the drawing.
2) Adjust the job on the chuck of CNC machine.
3) Start the machine and enter the program.
4) Center the tool with job by using XZ coordinates in absolute system.
5) Start facing and turning operations on job.
• G02 Clockwise
• G03 Counter clock wise

PROGRAM

COMMENTS
On the CNC lathe machine or CNC Simulator the G02 and G03 commands are used for
making round dimensions on the work piece, the G02 being used for clock-wise and
G03 being used for counter-clockwise dimensional cuts. The round metallic slabs and
arches are best made from these commands with high precision.

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 EXPERIMENT # 12c

OBJECTIVE

To do internal and external tapering using G77 code

APPARATUS

CNC Lathe machine, High speed single cutting tool, chuck key, Vernier caliper, Teflon.

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PROCEDURE:

1) Give the data in digit and alphabet form through the panel of the CNC lathe
machine according to the drawing.
2) Adjust the job on the chuck of CNC machine.
3) Start the machine and enter the program.
4) Center the tool with job by using XZ coordinates in absolute system.

PROGRAM

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COMMENTS
In CNC lathe or CNC Simulator the G77 code is used for the external tapering process.
We can feed data in digit and alphabet form through the panel of the CNC lathe machine
according to the drawing. By processing the codes the machine the start to work and by
holding the work piece in its jaws it will perform the external tampering with accuracy
as well as precision.

EXPERIMENT # 12d

OBJECTIVE
To perform rough and finish turning cycles using CNC Lathe

APPARATUS

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CNC Lathe machine, High speed single cutting tool, chuck key, Vernier caliper, Teflon.

FINISH TURNING CYCLE: G70

Format: G70 P_ L_
P: specify the real starting line number
L: specify real ending line number

ROUGH CYLINDRICAL TURNING COMPOUND-CYC: G71

Format: G71 L_ Q_ R_ I_ K_ F_ S_ T_

EXPLANATION

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L: describe the program block quantity of final track (not include current block and
start from the next block). Range: 1---99.
Q: feed value per time in X-axis direction, denote by radius value, no symbol. If no
define, will decide by user parameter N0.6
R: retracting value per time in X-axis direction, denote by radius value, no symbol. If
no define, will decide by user parameter N0.7
I: finish machining allowance in X-axis direction, denote by diameter/radius value, no
symbol. If no define, will decide by user parameter N0.8
K: finish machining allowance in Z-axis direction, no symbol. If no define, will decide
by user parameter N0.9
F: cutting feed speed
S: spindle speed
T: tool.

NOTE

1) There are four kinds of shape raised by using G71 instruction (as figure), but no
matter what kind
Shape, the tool move and cut parallel with Z-axis.
2) There can only be G01, G02, G03 instructions in the program blocks from A to B,
but, must ensure the
Dimension data of X and Z is simplex increasing or decreasing.
3) Sub-program can’t be called in the program blocks from A to B.

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4) Cutting instruction of finish turning cycle should closely follow behind instruction
G71.
5) Finish turning allowance I in X-axis direction use radius to express allowance.
6) All the addresses of Q, R, I, K in the instruction are non-symbol, the direction both
feed and retraction is automatically determined by system.
7) If the addresses of Q, R, I, K in the instruction are not specified, will decide by “user
parameter”
8) The addresses of Q, R, I, K in the instruction are not mode.
9） user parameter No.10 decide whether instruction execute auto finish turning.

N1 T0102 （select tool No.1, establish work coordinates system）

N2 M03 S500 M08 （spindle CW at speed 500r/min, cool open）
N4 G00 X60 Z10 （rapid positioning）
N5 G71 L3 Q3 R1 I0.5 K0.5 F150 （encircle rough turning Cycle）
N6 X20 Z0
N7 Z-30
N8 X50

N9 G00 X60 Z10 （rapid retract tool）

N10 M09 M05 （spindle stops, cool close ）

N11 M30 （program end ）

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PROCEDURE

1) Give the data in digit and alphabet form through the panel of the CNC lathe
machine according to the drawing.
2) Adjust the job on the chuck of CNC machine.
3) Start the machine and enter the program.
4) Center the tool with job by using XZ coordinates in absolute system.

PROGRAM

COMMENTS
The rough turning cycle can be done by the command Format: G71 L_ Q_ R_ I_ K_
F_ S_ T_ and the finish turning cycle is done by the command Format: G70 P_ L_. In
the rough turning process no matter what kind the tool moves and cuts parallel with
Z-axis. Finish turning allowance I in X-axis direction use radius to express allowance.
By giving the instructions the machine will automatically preform the task with great
accuracy and precision.

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