Manufacturing ProcessesManufacturing Processes

Definition:- The process of converting Definition:- The process of converting the raw material into finished the raw material into finished products by using certain processes products by using certain processes and/or machines.and/or machines.

ClassificatioClassificationn

Metal joining processesMetal joining processes

Definition:-Small components are Definition:-Small components are manufactured individually and then manufactured individually and then joined together to form the joined together to form the product.Such processes are called product.Such processes are called metal joining processes.metal joining processes.

Types of Metal Joining Types of Metal Joining ProcessesProcesses

Permanent Joints:-Permanent Joints:- WeldingWelding BrazingBrazing SolderingSoldering Adhesive bendingAdhesive bending

Temporary Joints:-Temporary Joints:- Mechanical Fasteners (Nuts, bolts, Mechanical Fasteners (Nuts, bolts,

rivets)rivets)

WeldingWelding Definition:- The process of joining Definition:- The process of joining

two metallic parts together by two metallic parts together by heating them to a plastic or semi heating them to a plastic or semi molten state, with or without the molten state, with or without the application of a pressure and with or application of a pressure and with or without a filler material.without a filler material.

ClassificationClassification

Pressure Welding( Plastic welding)Pressure Welding( Plastic welding) Parts to be joined are forced together by Parts to be joined are forced together by

an external pressurean external pressure Does not require filler materialDoes not require filler material Non-pressure welding( Fusion Non-pressure welding( Fusion

welding)welding) Metals parts to be joined are joined by Metals parts to be joined are joined by

heating without external pressure.heating without external pressure. Generally require filler material.Generally require filler material.

Pressure WeldingPressure Welding

Forge WeldingForge Welding Resistance WeldingResistance Welding Pressure Thermit WeldingPressure Thermit Welding

(Electric) Resistance (Electric) Resistance WeldingWelding

Heating is due to resistance of metal Heating is due to resistance of metal parts.parts.

The external pressure on the parts to The external pressure on the parts to be joined is applied by two be joined is applied by two electrodes.electrodes.

No filler material is used.No filler material is used. Heat generated, H= IHeat generated, H= I2RTRT

ClassificationClassification

Spot weldingSpot welding Seam weldingSeam welding Projection weldingProjection welding

Resistance Welding (Spot)Resistance Welding (Spot)

Seam weldingSeam welding

Electrodes used are roller electrodes.Electrodes used are roller electrodes. Series of overlapping spots are Series of overlapping spots are

obtained.obtained. Spot weld is made every time current Spot weld is made every time current

reaches its peak during A.C. cycle reaches its peak during A.C. cycle (1/50(1/50thth sec) resulting into continuous sec) resulting into continuous seam of overlapping weld spots.seam of overlapping weld spots.

Suitable for thin metal sheets only.Suitable for thin metal sheets only.

Seam WeldingSeam Welding

Resistance WeldingResistance Welding

Advantages:-Advantages:-

1)1) No filler material required.No filler material required.

2)2) Fast and hence suitable for mass Fast and hence suitable for mass productionproduction

3)3) Dissimilar materials can be welded.Dissimilar materials can be welded.

4)4) Process can be automatedProcess can be automated

5)5) Does not require skilled workerDoes not require skilled worker

Resistance WeldingResistance Welding

Disadvantages:-Disadvantages:-

1)1) Suitable only for partsSuitable only for parts

2)2) Cost is highCost is high

Applications:-Applications:-

1)1) Automobile bodiesAutomobile bodies

2)2) Buiding of ships, aircraftsBuiding of ships, aircrafts

3)3) Manufacturing of tubes, tanksManufacturing of tubes, tanks

Non-Pressure (Fusion) Non-Pressure (Fusion) WeldingWelding

Metals parts to be joined are joined Metals parts to be joined are joined by heating without external pressure.by heating without external pressure.

Generally require filler material.Generally require filler material. Types:-Types:- Electric arc weldingElectric arc welding Gas WeldingGas Welding Non-pressure thermit weldingNon-pressure thermit welding

Electric arc weldingElectric arc welding

-ve terminal of power supply is -ve terminal of power supply is attached to the electrode, while +ve attached to the electrode, while +ve terminal is attached to the terminal is attached to the workpieces. workpieces.

An electric arc is struck between an An electric arc is struck between an electrode and workpiece generating electrode and workpiece generating very high temperature. very high temperature.

Electric arc weldingElectric arc welding

Classification:- Classification:- Shielded metal arc welding (SMAW)Shielded metal arc welding (SMAW) Tungsten Inert Gas (TIG) arc weldingTungsten Inert Gas (TIG) arc welding Metal Inert Gas (MIG) arc weldingMetal Inert Gas (MIG) arc welding Carbon arc weldingCarbon arc welding

Electric arc weldingElectric arc welding

Electric arc weldingElectric arc welding

Advantages:-Advantages:-

1)1) Suitable thin as well as thick jobs.Suitable thin as well as thick jobs.

2)2) Complecated shapes can be Complecated shapes can be welded.welded.

3)3) Good quality and high strength.Good quality and high strength.

4)4) Less cost and simple.Less cost and simple.

5)5) Does not require external pressure.Does not require external pressure.

Electric arc weldingElectric arc welding Disadvantages:-Disadvantages:-1)1) Requires filler materialRequires filler material2)2) Time required is more as electrode is to Time required is more as electrode is to

be replaced after consumption.be replaced after consumption.3)3) Skilled worker is required.Skilled worker is required.4)4) Applications:- Applications:- 1)Manufacturing of Bridges, towers, boilers, 1)Manufacturing of Bridges, towers, boilers,

tanks, nuclear reactors.tanks, nuclear reactors.2) Door, window frames, grills and other 2) Door, window frames, grills and other

fabrication works.fabrication works.

Shielded Metal Arc WeldingShielded Metal Arc Welding

Shielded Metal Arc WeldingShielded Metal Arc Welding

Heating is done due to the electric Heating is done due to the electric arc between a flux coated arc between a flux coated consumable metal electrode and consumable metal electrode and workpiece.workpiece.

No external pressure.No external pressure. Flux provides protective gas shield Flux provides protective gas shield

around the molten metal to avoid around the molten metal to avoid oxidation.oxidation.

Tungsten Inert Gas (TIG) Arc Tungsten Inert Gas (TIG) Arc WeldingWelding

Shielding around the molten metal is Shielding around the molten metal is provided by the inert gas like helium, provided by the inert gas like helium, argon, etc.argon, etc.

Tungsten electrode which is non-Tungsten electrode which is non-consumable.consumable.

A separate filler material is used if A separate filler material is used if required.required.

Inert gas flows around the tungsten Inert gas flows around the tungsten electrode through a nozzle. It removes electrode through a nozzle. It removes contaminants from the workpieces.contaminants from the workpieces.

Tungsten Inert Gas (TIG) Arc Tungsten Inert Gas (TIG) Arc WeldingWelding

Tungsten Inert Gas (TIG) Arc Tungsten Inert Gas (TIG) Arc WeldingWelding

Applications:-Applications:- Produces high quality welds for Produces high quality welds for

materials like Stainless steel, C.I., Cu materials like Stainless steel, C.I., Cu and Al alloys, titanium, magnesium, and Al alloys, titanium, magnesium, etc.etc.

Used in food processing and Used in food processing and pharmaceutical industries.pharmaceutical industries.

Metal Inert Gas (MIG) arc Metal Inert Gas (MIG) arc WeldingWelding

Heating due to Electric arc between Heating due to Electric arc between Consumable metal electrode and the Consumable metal electrode and the workpieces.workpieces.

Shielding around the molten metal is Shielding around the molten metal is provided by the inert gas like helium, provided by the inert gas like helium, argon, etc.argon, etc.

Inert gas flows around the consumable Inert gas flows around the consumable metal electrode through a nozzle. It metal electrode through a nozzle. It removes contaminants from the removes contaminants from the workpieces.workpieces.

Metal Inert Gas (MIG) arc Metal Inert Gas (MIG) arc WeldingWelding

Applications:- Similar to TIG weldingApplications:- Similar to TIG welding

Comparison between TIG and Comparison between TIG and MIG weldingMIG welding

Sr.NSr.No.o.

ParameterParameter TIGTIG MIGMIG

1.1. ElectrodeElectrode Non-consumableNon-consumable ConsumableConsumable

2.2. ElectrodeElectrode Tungsten wireTungsten wire Metal wire Metal wire similar to similar to workpieceworkpiece

3.3. Electric arcElectric arc Without melting wireWithout melting wire Metal wire Metal wire meltsmelts

4.4. Filler materialFiller material SeparateSeparate SameSame

5.5. SpeedSpeed SlowSlow FastFast

6.6. ApplicationApplication Thin metal sectionThin metal section Thin as well as Thin as well as thick metalsthick metals

7.7. CostCost LowLow HighHigh

Comparison between Electric Comparison between Electric Resistance and Electric Arc Resistance and Electric Arc

WeldingWeldingSr.Sr.

NoNo..

ParameterParameter ResistanceResistance ArcArc

1.1. TypeType Pressure weldingPressure welding Non-pressure Non-pressure weldingwelding

2.2. HeatingHeating Due to resistance of Due to resistance of metal partsmetal parts

Due to electric arc Due to electric arc between electrode between electrode and workpiecesand workpieces

3.3. Filler materialFiller material Not requiredNot required RequiredRequired

4.4. SuitabilitySuitability Thin partsThin parts Thin and thick partsThin and thick parts

5.5. OperatorOperator Not skilledNot skilled SkilledSkilled

6.6. ApplicationApplication Automobile bodies, Automobile bodies, ships, aircraftsships, aircrafts

Bridges, Towers, Bridges, Towers, fabrication worksfabrication works

Gas WeldingGas Welding

Non-pressure weldingNon-pressure welding Heating is due to combustion of Heating is due to combustion of

gases like acetylene, propane, gases like acetylene, propane, butane, etc.butane, etc.

Filler material is used.Filler material is used.

Gas WeldingGas Welding

Gas WeldingGas Welding

Advantages:-Advantages:-1)Controllable flame temp.1)Controllable flame temp.2)Portable equipment2)Portable equipment3)3) Initial cost low.Initial cost low.Disadvantages:-Disadvantages:-1)Expensive gases1)Expensive gases2)Safety problems2)Safety problems3)Not suitable for thick workpieces3)Not suitable for thick workpieces

Gas WeldingGas Welding

Applications:-Applications:- Sheet metal fabricationSheet metal fabrication Automobile bodiesAutomobile bodies Building of ships, aircraftsBuilding of ships, aircrafts