Darshan Institute of Engineering & Technology · 2019-11-19 · Figure 4.2 Power source for TIG...

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Darshan Institute of Engineering & Technology Certificate This is to certify that Mr./Ms.__________________________________________ Enrollment No. ____________________ Branch: - Mechanical Engineering Semester: IV has satisfactory completed the course in the subject Manufacturing Processes II (2141908) in this institute. Date of Submission: - __________________________ Staff in Charge Head of Department

Transcript of Darshan Institute of Engineering & Technology · 2019-11-19 · Figure 4.2 Power source for TIG...

Darshan Institute of Engineering & Technology

Certificate

This is to certify that Mr./Ms.__________________________________________

Enrollment No. ____________________ Branch: - Mechanical Engineering

Semester: IV has satisfactory completed the course in the subject Manufacturing

Processes – II (2141908) in this institute.

Date of Submission: - __________________________

Staff in Charge Head of Department

DARSHAN INSTITUTE OF ENGG. & TECH.

Department of Mechanical Engineering

B.E. Semester – VI

Manufacturing Processes – II (2141908)

List of Experiments

Sr.

No. Title

Date of

Performance

Date of

Submission Sign Remark

1. Preparation of Wooden Pattern

for Sand Casting Process.

2. Demonstration of Various Stages

of Sand Casting Process.

3. Practice of Manual Metal Arc

(MMA) Welding process.

4. Practice of Tungsten Inert Gas

(TIG) Welding Process.

5. Practice of Metal Inert Gas

(MIG) Welding Process..

6. Practice of Oxy - Acetylene Gas

Welding Process.

7. To Study about Plastic

Processing Technology.

8. To Study about Sheet Metal

Forming Processes.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.1

EXPERIMENT – 2

AIM: Demonstration of Various Stages of Sand Casting Process.

2.1 INTRODUCTION

Several casting processes have been developed to suit economic production of cast

products with desired mechanical properties, dimensional accuracy, surface finish

etc.

The various processes differ primarily in mold material (whether sand, metal or

other material) and pouring method (gravity, pressure or vacuum).

Any casting process involves three basic steps, i.e. mould making, melting and

pouring of metals into the mould cavity, and removal and finishing of casting after

complete solidification.

Figure 2.1 Flow chart of sand casting process

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.2

Figure 2.2 Mould for sand casting process

2.2 MOULD MAKING

1. Place the drag part of the pattern with parting surface down on ground or molding

board at the center of the drag (flask).

2. Riddle moulding sand to a depth of about 2 cm in the drag and pack this sand

carefully around the pattern with fingers.

3. Heap more moulding sand in the drag and ram with rammer carefully.

4. Strike off the excess sand using strike bar.

5. Make vent holes to within 1 cm of the pattern surface in the drag.

6. Turn this complete drag and place the cope portion (flask) over it.

7. Place the cope half of the pattern over the drag pattern matching the guide pins and

apply parting sand over the parting surface. Also place the sprue pin and riser pin in

proper positions.

8. Remove the sprue and riser pins and make a pouring basin. Separate the cope and

drag halves, and place them with their parting faces up.

9. Moisten sand at the copes of the pattern and remove pattern halves carefully using

draw spikes.

10. Cut gate and runner in the drag. Repair and clean the cavities in the two mould

halves.

11. Place the core in position, assembled the two mould halves assemble and clamp

them together.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.3

Figure 2.3 Mould making for sand casting

Figure 2.4 Mould of mechanical components

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.4

2.3 MELTING AND POURING

1. Melt the metal in the furnace. Use appropriate fluxes at proper stages and measure

metal temperature from time to time.

2. Pour the molten metal into the pouring ladle at a higher temperature (say 100 0C

higher than the pouring temperature). As soon as the desired pouring temperature is

reached, pour the liquid metal into the mould in a steady stream with ladle close to

the pouring basin of the mould. Do not allow any dross or slag to go in.

A) Sand mould open B) Sand Mould closed

Figure 2.5 Pouring liquid metal into mould

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.5

Table 2.1 Melting and pouring temperature of various metals

Sr. No. Material Melting temperature

(0C)

Pouring temperature

(0C)

1. Grey cast iron 1370 1510 – 1590

2. Cast steel 1480 1600 – 1720

3. Copper 1083 1130 – 1200

4. Nickel 1453 1500 – 1590

5. Aluminum 660 700 – 780

6. Zinc 420 450 – 480

7. Lead 327 350 – 380

8. Tin 232 280 – 290

9. Cu – Ni alloy

(Cu – 96%, Ni – 4%)

1175 1220 – 1280

10. Gun metal

(Cu – 85%, Sn – 5%, Zn

– 5%, Pb – 5%)

1040 1100 – 1180

REPORT THE FOLLOWING

1. Various types of sand and their composition.

2. Type of moulding sand used in experiment.

3. Melting and poring temperature of the material used for the casting.

Table 2.2 Commonly used material for casting in industry (ASTM standard)

Material Composition

Melting

temperature

(cC)

WCB

WCC

LCB

LCC

CF3

CF8

CF3M

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.6

WC1

Table 2.3 Commonly used material for casting in industry (DIN standard)

Material Composition

Melting

temperature

(cC)

1.0619

1.0625

1.1131

1.6220

1.5422

1.5419

1.7357

1.7379

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 2.7

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 3.1

EXPERIMENT – 3

AIM: Practice of Manual Metal Arc (MMA) Welding process.

3.1 INTRODUCTION

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.

3.2 PRINCIPLE OF ARC WELDING PROCESS

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 3800 0C.

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.

Various types of arc welding processes are listed below.

1. Manual metal arc welding 2. Submerged arc welding

3. TIG welding 4. Plasma arc welding

5. MIG welding

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 3.2

Figure 3.1 Principle of arc welding process

3.3 ELECTRODE DESIGNATION SYSTEM AND STANDARD RANGE OF USE

Various electrodes can be used for various application. Selection of electrode is made

on the basis of thickness of material, welding machine specification, type of joint,

length of joint, position of welding etc.

Figure 3.2 Electrode designation system

After selecting a proper combination, selection of welding parameter is required for

sound weld. Table 3.1 suggests some welding parameter range for various application.

Table 3.1 Standard current and voltage range of E7018 electrode (MFG. by HONAVAR Electrodes Pvt.

Ltd, India)

Electrode Diameter (mm) Length (mm) Current (Amp) Voltage (V)

2.5 350 80 – 100 24 – 25

3.15 450 100 – 135 24 – 25

4.0 450 140 – 190 24 – 25

5.0 450 180 – 250 24 – 25

6.3 450 250 – 320 24 – 25

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 3.3

REPORT THE FOLLOWING

1. Position of welding during practice.

2. Designation of electrode and welding parameters used during practice.

3. List various coating materials used. Also suggest polarity for specific coating material.

4. List various manufacturers and their welding parameter range of welding electrode.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 3.4

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.1

EXPERIMENT – 4

AIM: Practice of Tungsten Inert Gas (TIG) Welding Process.

4.1 PRINCIPLE OF TIG WELDING PROCESS

TIG welding works on same principle of arc welding. In a TIG welding process, a high

intense arc is produced between tungsten electrode and work piece.

In this welding mostly work piece is connected to the positive terminal and electrode

is connected to negative terminal. This arc produces heat energy which is further

used to join metal plate by fusion welding.

A shielding gas is also used which protect the weld surface from oxidization.

Figure 4.1 Principle of TIG welding process

4.2 EQUIPMENTS

4.2.1 Power Source

The first unit of equipment’s is power source. A high current power source needed

for TIG welding. It uses both AC and DC power source.

Mostly DC current is used for stainless steel, Mild Steel, Copper, Titanium, Nickel

alloy, etc. and AC current is used for aluminum, aluminum alloy and magnesium.

Power source consist a transformer, a rectifier and electronic controls. Mostly 10 –

35 V is required at 5-300 A current for proper arc generation.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.2

Figure 4.2 Power source for TIG welding

4.2.2 TIG Torch

It is a most important part of TIG welding. This torch has three main parts, tungsten

electrode, collets and nozzle.

This torch is either water cooled or air cooled. In this torch, collet is used to hold the

tungsten electrode. These are available in varying diameter according to diameter of

tungsten electrode.

The nozzle allows the arc and shielded gases to flow into welding zone. The nozzle

cross section is small which gives high intense arc.

There are passes of shielded gases at nozzle. The nozzle of TIG needs to replace in

regular interval because it wears out due to presence of intense spark.

Alumina gas lens nozzles are available in various size for various application.

A) B)

Figure 4.3 A) TIG Tourch B) Alumina gas lens nozzles

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.3

Table 4.1 Alumina gas lens nozzle size chart

Description Size I.D. (mm)

Alumina gas lens nozzle 4 11

Alumina gas lens nozzle 5 8

Alumina gas lens nozzle 6 19

Alumina gas lens nozzle 7 16

Alumina gas lens nozzle 8 13

Large alumina gas lens nozzle 12 19

Large alumina gas lens nozzle 10 16

Alumina gas lens nozzle 8 13

Alumina gas lens nozzle 7 11

Alumina gas lens nozzle 6 10

Alumina gas lens nozzle 5 8

Alumina gas lens nozzle 4 6

Alumina gas lens nozzle 11 18

Large alumina gas lens nozzle 8 13

Large alumina gas lens nozzle 6 10

Large E alumina gas lens nozzle 8 13

Large E alumina gas lens nozzle 6 10

4.2.3 Shielding Gas Supply System:

Normally argon or other inert gases are used as shielded gas. The main purpose of

shielded gas to protects the weld from oxidization.

Shielded gas does not allow coming oxygen or other air into welded zone. The

selection of inert gas is depending upon metal to be welded.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.4

Figure 4.4 Shielding gas (Argon) cylinder and regulator

Some suggested nozzle sizes along with the gas flow rate which can be used for

various material thickness are given in table below.

Table 4.2 Suggested nozzle sizes and gas flow rate

Material thickness (mm) Gas nozzle diameter (mm) Shielding gas flow rate (litre/min)

Argon Helium

Up to 1 9.5 3.4 7.5

1 to 3 9.5 4.5 9.5

3 to 5 12.5 5.6 11.8

5 to 9 12.5 7.0 14.2

9 to 12 16 8.0 16.5

>12 25 12.0 21.0

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.5

Table 4.3 Electrode sizes and current ranges

Typical current range (Amp)

DC AC

DCEN 70 % penetration Wave (50/50) balanced

Tungsten

diameter

(mm)

Gas

cup I.D

(mm)

Ceriated,

Lanthanated,

Thoriated

Pure

Ceriated,

Lanthanated,

Thoriated

Pure

Ceriated,

Lanthanated,

Thoriated

1.016 9.525 15 – 80 20 – 60 15 – 80 10 – 30 20 – 60

1.524 9.525 70 – 150 50 – 100 70 – 150 30 – 80 60 – 120

2.362 12.7 150 – 250 100 – 160 140 – 235 110 – 130 100 – 180

2.5 25 260 – 340 170 – 240 240 – 300 140 – 180 190 – 290

4.2.4 Filler Material:

For welding of thin sheets filler material is not used.

For welding of thick sheets, filler material is used in form of rods which are directly

feed into weld zone manually.

Figure 4.5 Filler wire for TIG welding

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.6

Figure 4.6 – TIG welding process set-up

REPORT THE FOLLOWING:

1. Type and size of electrode used in welding process.

2. Size of gas nozzle used with TIG torch.

3. Base metal type, its thickness and melting temperature.

4. Type and diameter of filler wire used.

5. Type of power source used and value of amperage during practice.

6. List down well known manufacturers of TIG welding machines with its specifications.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 4.7

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.1

EXPERIMENT – 5

AIM: Practice of Metal Inert Gas (MIG) Welding Process.

5.1 PRINCIPLE OF MIG WELDING PROCESS

MIG works on same principle of TIG or arc welding. It works on basic principle of

heat generation due to electric arc.

This heat is further used to melt consumable electrode and base plates metal

which solidify together and makes a strong joint.

The shielded gases are also supplied through nozzle which protect the weld zone

from other reactive gases. This gives good surface finish and a stronger joint.

Figure 5.1 Principle of MIG welding process

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.2

5.2 EQUIPMENTS

MIG welding setup is shown in figure 5.2. Basic components are power source, MIG torch,

shielding gas system and wire feeding system.

Figure 5.2 MIG welding equipment

5.2.1 Power Source

In this type of welding process, a DC power supply is used with reverse polarity.

Reverse polarity means the electrode or in case of MIG welding electrode wire is

connected positive terminal and work piece to negative terminal.

It is due to principle of electric circuit which state that 70% of heat is always on

positive side. So reverse polarity ensures that the maximum amount of heat liberate

at tool side which melt the filler metal in proper way.

Straight polarity can cause unstable arc that result into large spatter. The power

source consists a power supply, a transformer, a rectifier which change AC into DC

and some electronic controls which control the current supply according to weld

requirement.

5.2.2 MIG Torch

This torch is slightly different as used in TIG welding. In this torch there is a

mechanism which hold the wire and supply it continuously with the help of wire

feed.

The front end of the torch is fitted with a nozzle. The nozzle is used to supply inert

gases. These gases form a shielding area around the weld zone and protect it from

oxidization.

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.3

The welding torch is air cooled or water cooled according to the requirement. For

high current supplied, the torch is water cooled and for low supply it is air cooled.

Figure 5.3 Typical MIG torch

5.2.3 Shielding Gas Supply System

The primary function of shielding gases is to protect weld area from other

reactive gases like oxygen etc. which can affect the strength of welding joint.

These shielding gases are also form plasma which helps in welding.

The choice of gas is depending on the welding material. Mostly argon, helium

and other inert gases are used as shielding gas

A) B) C)

Figure 5.4 A) Co2 gas cylinder B) Regulator C) Preheater

5.2.4 Wire Feeder System

We know that MIG welding needs continuous consumable electrode supply for

welding two plates. This consumable electrode used in form of wire. These wire

is continuously supplied by wire feed mechanism or system.

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.4

It controls the speed of the wire and also pushes the wire form welding torch to

welding area. These are available in different shapes and sizes.

It consists a wire pool holder, a driving motor, a set of driving rollers and wire

feed controls.

The wire feed speed is directly control the current supply through power supply.

If the wire feeding speed is high, it required more current in welding zone to

produce proper heat for melting of it.

Figure 5.5 Wire feeding system

Figure 5.6 Feeding wire spool

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.5

Table 5.1 Ranges of wire feed rate in CO2 welding (Ador Welding Ltd., India)

Wire feed speed (m/min)

Wire diameter (mm) Spray type arc (30-40 V) Short circuit arc (16-22V)

0.8 5.0 – 15 (150-250 amp) 2.5 – 7.5 (60-160 amp)

1.2 5.0 – 15 (200-350 amp) 2.0 – 3.8 (100-175 amp)

1.6 5.0 – 8.8 (350-500 amp) 1.5 – 2.0 (120-180 amp)

2.4 3.8 – 7.5 (500-750 amp) 1.25 – 1.6 (150-200 amp)

Table 5.2 Typical arc voltage for MIG welding of various metals (Ador Welding Ltd., India)

Drop transfer

(Electrode diameter = 1.6mm)

Short circuit arcs

(Electrode diameter = 0.9mm)

Metal Ar He 25%Ar

75%He

Ar – O2

(1-5%) CO2 Ar

Ar –

O2 (1-

5%)

75%Ar

25%He CO2

Al 25 30 29 - - 19 - - -

Mg 26 - 28 - - 16 - - -

Carbon Steel - - - 28 30 17 18 19 20

Low alloy steel - - - 28 30 17 18 19 20

SS 24 30 28 26 - 18 19 21 -

Ni 26 30 28 - - 22 - - -

Ni – Cu alloy 26 30 28 - - 22 - - -

Ni – Cr – Fe alloy 26 36 33 - - 22 22 - -

Cu 30 32 30 - - 24 - - -

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.6

Table 5.3 Spray transfer currents for a variety of electrodes (Ador Welding Ltd., India)

Wire electrode

material

Wire electrode

diameter (mm)

Min. Arc current

(Amp)

Mild steel 0.76 150

Mild steel 0.89 165

Mild steel 1.14 220

Mild steel 1.59 275

Stainless steel 0.89 170

Stainless steel 1.14 225

Stainless steel 1.59 285

Aluminium 0.76 95

Aluminium 1.14 135

Aluminium 1.59 180

Deoxidized copper 0.859 180

Deoxidized copper 1.14 210

Deoxidized copper 1.59 310

Silicon bronze 0.89 165

Silicon bronze 1.14 205

Silicon bronze 1.59 270

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.7

Table 5.4 Mild steel butt welds welding parameters (Electrode dia. = 0.8 mm)

(Ador Welding Ltd., India)

Thickness (mm) Gap (mm) Wire feed (m/min) Arc (V) Current (A)

1 0 2.8 – 3.8 16 – 17 65 – 80

1.2 0 3.2 – 4.0 18 – 19 70 – 85

1.6 0.5 4.0 – 4.8 19 – 20 85 – 95

2.0 0.8 5.8 – 7.0 19 – 20 110 – 125

2.5 0.8 7.0 – 8.4 20 – 21 125 – 140

3.0 1.5 7.0 – 8.4 20 – 21 125 – 140

REPORT THE FOLLOWING:

1. Type and size of electrode used in welding process.

2. Base metal type, its thickness and melting temperature.

3. Type and diameter of filler wire used. Type of shielding gas used.

4. Various welding parameters used for practice.

Manufacturing Processes - II (2141908)

Department of Mechanical Engineering Prepared by: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 5.8

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.1

EXPERIMENT – 6

AIM: Practice of Oxy - Acetylene Gas Welding Process.

6.1 PRINCIPLE OF GAS WELDING PROCESS

Gas welding is a most important type of welding process. It is done by burning of fuel

gases with the help of oxygen which forms a concentrated flame of high temperature.

This flame directly strikes the weld area and melts the weld surface and filler material.

The melted part of welding plates diffused in one another and create a weld joint after

cooling.

This welding method can be used to join most of common metals used in daily life.

6.2 GAS WELDING EQUIPMENTS

Figure 6.1 Gas welding equipments

6.2.1 Welding Torch

Welding torches are most important part of gas welding. Both the fuel gas and oxygen

at suitable pressure fed through hoses to the welding torch.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.2

There are valves for each gas witch control the flow of gases inside the torch. Both

gases mixed there and form a flammable mixture.

These gases ignite to burn at the nozzle. The fire flame flow through nozzle and strikes

at welding plates.

The nozzle thickness depends on the size of the welding plates and material to be

welded.

6.2.2 Cylinders and regulators

Acetylene and oxygen gas is stored in compressed gas cylinders. These gas Cylinders

differ widely in capacity, design and color code.

However, in most of the countries, the standard size of these cylinders is 6 to 7 m3

and is painted black for oxygen and maroon for acetylene.

An acetylene cylinder is filled with some absorptive material, which is saturated with

a chemical solvent acetone. Acetone has the ability to absorb a large volume of

acetylene and release it as the pressure falls.

If large quantities of acetylene gas are being consumed, it is much cheaper to generate

the gas at the place of use with the help of acetylene gas generators. Acetylene gas is

generated by carbide-to-water method.

The cylinder and hose connections have left-handed threads on the acetylene

regulator while these are right handed on the oxygen regulator.

A) B)

Figure 6.2 A) Oxygen regulator B) Acetylene regulator

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.3

6.2.3 Arrestor

These are essential to avoid accidents during welding. In case of flash back of flame, it

prevents it to reach into the filled cylinder. Separate arrestors are required for oxygen

and acetylene gas cylinders. Two arrestors are attached with the hose at the cylinder

regulator end and two at the torch end

Figure 6.3 Arrestors

6.2.4 Hoses

The hoses are color-coded for visual identification. The color of the hoses varies

between countries. In the United States, the oxygen hose is green, and the fuel hose

is red. In the UK and other countries, the oxygen hose is blue (black hoses may still be

found on old equipment), and the acetylene (fuel) hose is red.

Figure 6.4 Gas welding hoses

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.4

Table 6.1 Oxygen hose standards size

Nominal size I.D. (mm) O.D. (mm) Maximum working pressure

(MPa) Weight (g/m)

6 6.4 13.2 2.0 130

8 8.0 15.0 2.0 160

9 9.5 16.5 2.0 180

19 19.0 30.0 1.0 580

25 25.4 37.5 1.0 790

Table 6.2 Acetylene hose standards size

Nominal size I.D. (mm) O.D. (mm) Maximum working pressure

(MPa) Weight (g/m)

6 6.3 12.3 0.15 120

8 8.0 14.2 0.15 140

9 9.5 15.9 0.15 170

19 19.0 30.0 0.15 590

25 25.4 37.5 0.15 800

6.3 FLAME TEMPERATURE

Any hydrocarbon can can be used for gas welding. But experimentally, oxy – acetylene

gas welding gives the maximum flame temperature.

Acetylene, Hydrogen, Propane, Butane, Natural gas, LPG etc. can be used in various

applications. But selection of fuel gas depends on economics of welding, base metal

properties and working conditions

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.5

Table 6.3 Temperature comparison of various gases

Fuel gas Flame temperature (0C)

In oxygen In air

Acetylene 3480 2650

Hydrogen 2980 2200

Propane 2925 2090

Butane 2980 2150

Natural gas 2775 2090

Table 6.4 Oxy - acetylene flame temperature

Ratio of O2 to C2H2 Type of flame Temperature (0C)

0.8 – 1.0 Carburizing 3065

0.9 – 1.0 Carburizing 3150

1.0 – 1.0 Neutral 3100

1.5 – 1.0 Oxidizing 3427

1.8 – 1.0 Oxidizing 3482

2.0 – 1.0 Oxidizing 3370

2.5 – 1.0 Oxidizing 3315

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.6

Table 6.5 Selection chart of filler metal, flame type and flux for various metals

Material Filler metals Flame type Flux

Aluminium Matching Slightly reducing Aluminium flux

Brass Neavy brass Slightly oxidizing Borax flux

Bronze Copper Slightly oxidizing Borax flux

Copper Copper Neutral -

Copper - Nickel Copper nickel Reducing -

Inconel Matching Slightly reducing Fluoride flux

Cast iron Cast iron Neutral Borax flux

Wrought iron Steel Neutral -

Lead Lead Slightly reducing -

Monel Matching Slightly reducing Monel flux

Nickel Nickel Slightly reducing -

Nickel - Silver Nickel - Silver Reducing -

Low alloy steel Steel Slightly reducing -

High carbon steel Steel Reducing -

Low carbon steel Steel Neutral -

Medium carbon steel Steel Slightly reducing -

Stainless steel Matching Slightly reducing Stainless steel flux

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.7

REPORT THE FOLLOWING:

1. Different types of flames produced during practise.

2. Type of base metal and filler metal used during practice.

3. Type of flame used for welding practice.

4. Various size of cylinders used and amount of gas filled into it.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 6.8

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.1

EXPERIMENT – 7

AIM: To Study about Plastic Processing Technology.

7.1 INTRODUCTION

Describing the types of plastics is a bit like looking at a giant family tree; unless you

know some of the people it does not make much sense. The resource: ‘curing’ explains

the basic chemistry of plastics, and describes the difference between thermoplastic

and thermoset plastics. They are like two branches of the family, and this section deals

with the largest branch, thermoplastics.

One difficulty with describing plastics, is that the same material with the addition of

just a single additive like a blowing agent or plasticizer, can make what appears to be

a very different material. Take polyurethane for example. It can be used as a clear

coating like varnish, expanded and rigid to form the core of a surfboard, and with a

plasticizer it can become a soft car seat.

7.2 TYPES OF PLASTICS

With plastics there are about 45 basic families, many with hundreds of offspring. We

will look at five main branches, mainly because they are plastics which you will be

familiar with. The five branches are; polyethylene, polypropylene, polystyrene, vinyl,

and polyethylene terephthalate.

7.1.1 Polyethylene

Most plastic household packaging is made from polyethylene. It is a versatile wax-like

thermoplastic in almost a thousand different grades with varying melting

temperatures, density and molecular weights. It has three main forms:

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.2

Table 7.1 Polyethylene types

Form Acronym Characteristics Uses

Polypropylene HDPE Hard to semi flexible, Waxy surface, opaque

Fertiliser bags, car petrol tanks, gas pipe, tanks and rope

Low Density LDPE Soft, flexible, waxy surface, translucent

Packaging film, bags, waterproof membranes, wire sheathing, pipes

Linear Low Density LLDPE Flexible, translucent, glossy, strong

Shopping bags, stretch wrap,

7.1.2 Polypropylene

It was developed in Italy in 1954 from catalysts used to form HDPE. It is very versatile,

and makes up about 12 per cent of the plastics used in Australia.

Table 7.2 Polypropylene types

Form Acronym Characteristics Uses

High Density

PP Hard, flexible, translucent, dry feel

Containers, appliances, toys, plumbing

7.1.3 Polystyrene

This is one of the lower cost plastics to produce and is the easiest to shape. Packaging

for a variety of products uses most of the plastic.

Table 7.3 Polystyrene types

Form Acronym Characteristics Uses

Polystyrene

PP Clear, glossy, rigid, brittle

Margarine containers

High HIPS Impact Opaque, tough, rigid

Refrigerator liners

Expanded

EPS Foamed, lightweight,

insulating Stubby holders moulded

packaging

Acrylonitrile Butadiene Styrene

ABS Rigid, tough, glossy, opaque

Hard hats, computer cases, wheel covers

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.3

7.1.4 Vinyls

Vinyls are among the most versatile of all thermoplastics, ranging from soft pliable

films to rigid structural forms. They are cheap to make because about half the raw

material comes from rock salt.

Table 7.4 Vinyls types

7.3 COMPONENTS MANUFACTURED BY PLASTIC PROCESSING METHODS

Various plastic processing methods are listed below.

1 Blow moulding 2 Transfer moulding

3 Compression moulding 4 Extrusion moulding

5 Injection moulding

6 Calendaring

7 Thermoforming

8 Pressure forming

Figure 7.1 Blow molding components

Form Acronym Characteristics Uses

Plasticised PVC

Flexible, clear, elastic Car linings, blood bags,

floor covering

In- plasticised PVC Hard, rigid, clear Pipe, cordial bottles,

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.4

Figure 7.2 Transfer molding components

Figure 7.3 Compression molding components

Figure 7.4 Extrusion molding components

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.5

Figure 7.5 Injection molding components

Figure 7.6 Calendaring components

Figure 7.7 Thermoforming components

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REPORT THE FOLLOWING:

1. Give the name of industry visited during the course and components by it.

2. Type of manufacturing method and plastic material used in the industry.

3. Prepare a report regarding the visit during the course.

4. Case study regarding any of the plastic processing methods.

5. List various well known industries and plastic components manufactured by them.

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Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.1

EXPERIMENT – 8

AIM: To Study about Sheet Metal Forming Processes.

8.1 INTRODUCTION

Sheet metal work is very useful trade in engineering work and for our day-to-day

needs. Many articles (household and engineering) whose production by other

methods will be uneconomical and complicated are made from metal sheets.

For successful working in the trade, we must have a good knowledge of projective

geometry, development of surfaces and properties of different metals.

8.2 METALS USED IN SHEET METAL WORKING

There are different types of metals used in sheet metal work in the form' of sheets

and plates. The specifications of metal sheets are given in terms of their gauge

numbers, length and width Gauge number represents a thickness of metal sheets. The

higher the gauge number, the smaller the thickness.

Some of the important sheet metals are as follows:

Black iron

Black iron or uncoated sheet carries no artificial coating on its surface, but it is cheaper

than other types of metal sheets.

Components made from this type of metal are pans, tanks, cabinets, almirahs, stove

pipes, etc.

Galvanised iron

It is soft iron sheet carries zinc coating on its surface which make the surface good

looking and rust resistant.

Components made from this type of metal are storage tanks, buckets, heating ducts,

furnaces, gutters, pans, trunks, etc.

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Aluminum sheets

Due to low strength of aluminum sheets they are not used in their pure form, hence

suitable amount of silicon manganese, copper and iron are added. It offers high

resistance to corrosion and abrasion.

They are used in the manufacture of aero plane bodies, kitchenware and cabinets,

doors, windows arid building work, electrical appliances, etc.

Copper sheets

Copper sheets are costlier but offers good resistance to corrosion and relatively good

in appearance. They are reddish in colour, highly ductile and malleable.

They are used in applications like radiators of automobiles, heating appliance, gutters,

hoods and components in chemical plants.

Stainless steel

Stainless steel offers high resistance to corrosion and exhibits a bright surface.

It is used in the manufacture of food containing equipments, dairy equipments, food

processing plant, chemical plant, etc.

Tin plates

Tin plates are used for those iron sheets which are coated with pure tin.

Tin plates are used for making food containers, containers for cooking oils and ghee,

cans, etc.

8.3 METALS USED IN SHEET METAL WORKING

Various metal forming processes are listed below.

1 Forging

2 Deep drawing

3 Wire drawing

4 Extrusion

5 Rolling

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.3

Figure 8.1 Parts manufactured by forging process

Figure 8.2 Parts manufactured by deep drawing process

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.4

Figure 8.3 Rolled metallic sheets

Figure 8.4 Parts manufactured by extrusion process

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.5

REPORT THE FOLLOWING:

1. Give the name of industry visited during the course and components by it.

2. Type of metal forming process used and material of the components

3. Prepare a report regarding the visit during the course.

4. Case study regarding any of the metal forming process

5. List various well known industries and plastic components manufactured by them.

Manufacturing Processes - II (2141908) Department of Mechanical Engineering Prepared By: Jainik Makwana Darshan Institute of Engineering & Technology, Rajkot Page 7.6