PLASMA ARC MACHINING

&

LASER BEAM MACHINING

PRESENTED BY:-

SHUBHAM CHAURASIYA

PANJAB UNIVERSITY

PLASMA ARC MACHINING

CONTENTSIntroduction

Working Principle of PAM

Process Details of PAM

Applications of PAM

Advantages of PAM Process

Disadvantages of PAM Process

Conclusion

INTRODUCTION The plasma arc machining process was introduced to the industries

in 1964 as a method of bringing better control to the arc welding

process in lower current ranges.

Plasma-arc machining (PAM) employs a high-velocity jet of high-

temperature gas to melt and displace material in its path.

Today, plasma retains the original advantages it brought to industry

by providing an advanced level of control and accuracy.

Gases are heated and charged

to plasma state.

Plasma state is the superheated

and electrically ionized gases at

approximately 5000⁰C.

These gases are directed on the

workpiece in the form of high

velocity stream.

Working Principle of PAM

Process Details of PAM Plasma gun

Power supply

Cooling mechanism

Work piece

Plasma Gun The plasma gun consists of a tungsten electrode fitted in the

chamber.

The electrode is given negative polarity and nozzle of the gun is

given positive polarity.

A strong arc is established between the two terminals anode and

cathode.

There is a collision between molecules of gas and electrons of the

established arc.

Gas molecules get ionized and plasma state is formed.

Plasma is directed to the workpiece with high velocity.

Power Supply and Terminals

Power supply (DC) is used to develop two terminals in the plasma

gun.

A tungsten electrode is inserted to the gun and made cathode and

nozzle of the gun is made anode.

Heavy potential difference is applied across the electrodes to develop

plasma state of gases.

Work piece

Work piece of different materials can be processed by PAM

process.

Ex: aluminium, magnesium, stainless steels and carbon and

alloy steels.

Cooling Mechanism

Hot gases continuously comes out of nozzle so there are

chances of its over heating.

A water jacket is used to surround the nozzle to avoid its

overheating.

Applications of PAM• In tube mill application.

• Welding of cryogenic, aerospace and high temperature corrosion

resistant alloys.

• Nuclear submarine pipe system.

• Welding steel Rocket motor case.

• Welding of stainless steel tubes.

• Welding titanium plates up to 8mm thickness.

Advantages of PAM Process It gives faster production rate.

Very hard and brittle metals can be machined.

Small cavities can be machined with good dimensional accuracy.

Disadvantages of PAM Process Its initial cost is very high.

It is uneconomical for bigger cavities to be machined.

Inert gas consumption is high.

CONCLUSION In the latest field of technology respect to welding and machining,

plasma arc welding and machining have a huge success.

Due to its improved weld quality and increased weld output it is

been used for precision welding of surgical instruments, to

automatic repair of jet engine blades to the manual welding for

repair of components in the tool, die and mold industry.

But due to its high equipment expense and high production of

ozone, it’s been outnumbered by other advance welding

equipment like laser been welding and Electron beam welding.

To overcome the mentioned problem, it is been expected that soon

it will fetch with its minimum cons.

LASER BEAM MACHINING

CONTENTS Introduction

Type of Laser

Laser Application

Parameters Affecting LBM

Advantage

Disadvantage

INTRODUCTION Laser beam machining (LBM) is one of the most widely used

thermal energy based non-contact type advance machining process which can be applied for almost whole range of material.

As the name suggest it uses LASER (Light Amplification by Stimulated Emission of Radiaton ) for operations.

Laser is a coherent and amplified beam of Light.

Laser Beam Machining Used light energy from a laser to remove material by

vaporization and ablation

Energy is concentrated optically

Laser emits either continuous or pulsed light beam

Types of Laser

Types of

Laser

Gas Laser

Solid State Laser

Excimer Laser

Gas Laser Electric current is discharged through a gas to produce a

coherent light

Operate on the principle of converting electric energy into

laser light output

Gas acts as pumping medium to attain the necessary

population inversion

Common gas laser are CO2 Gas Laser, He-Ne Gas Laser

He-Ne Gas Laser

Solid State Laser Constructed by doping a rare earth element into a variety

of host materials

Pumped optically by arc lamps or flash lamps

Respond well to Q-switching

Ruby or Nd:YAG is the most common host material

Ruby Laser

Excimer Laser Uses a combination of an inert gas and reactive gas

Excimer is form of Ultraviolet Chemical Laser

Excimer is short for ‘excited dimer’

Operation:- Laser Cutting Cutting starts by drilling a hole by moving beam

Cutting speed depends on material and thickness

Both pulsed and continuous laser is used

Thickness ranges from 0.5-1 inch

Used for cutting complex geometry and for clean cutting

operation

Laser Application

Heavy Manufacturing

Seam & spot welding

Cladding & drilling

Light Manufacturing

Engraving

Drilling

Electronics

Skiving of circuits

Wire stripping

Medical

Cosmetic

Surgery

Hair removal

Parameter Affecting LBM• Working Material

• Assist Gases

• Focusing Lenses

• Laser Beam

• Environment

Laser Beam Machining

Advantages Non Contact

No solvent chemical

Selective material removal

Flexibility

Fully automated

Disadvantages Requires specially trained operators

Not for mass metal removal processes

Requires greater control of joint tolerances

Expensive equipment

Consumes much energy