ELECTRO DISCHARGE MACHINING(EDM)

A SEMINAR On

Presented By,Anuja JoshiME-CADME

COMMON MODERN MACHINING METHODS

EBM

PAM

ECGAJM

EDM

EDM It is also known as Spark-over-initiated

discharge machining as well as Spark erosion machining

It is probably most versatile of all electrical machining method.

The metal removal takes place due to erosion caused by the electric spark.

This process can apply on any material irrespective of its hardness, which is an electrical conductor.

SCHEMATIC DIAGRAM

DIFFERENT DIELECTRIC FLUIDS

Kerosene Certain aqueous solutions Transformers oil

FUNCTIONS OF DIELECTRIC FLUID

Flush out removed material

To act as insulator between tool & work piece

To cool workpiece & tool

EDM PROCESS CHARACTERISTICS

1) Material removal rate(MRR) rough s/f good s/f High current range MRR(but rough cut achieved) Low current range MRR(finished cut achieved)2) Good accuracy achieved3) Good surface finish

ADVANTAGES

1) Very thin & delegate parts can cut without distortion of material.

2) Accurate profiles can generate on tool & dies in hard condition also.

3) Irrespective of strength & hardness good electrical conductor material can be machined.

4) Any shape that imparted on the tool can be reproduced on work piece.

5) Tiny holes can be easily produced & drilled.6) Harder material can be machined at faster rate (Tungsten,

stainless steel, high strength steel alloys, Infolem)

DISADVANTAGES

1)Limited capacity2)Work piece should be good electrical conductor.3) Power requirement is on higher side.4) Too long machining time.

APPLICATIONS

1) •Machining of cavities(in dies for punching & lagging operations)

2) •Making tiny holes in nozzles

3) •M/c ing hard to machine metals used in Aircraft industries, Missile industries, Nuclear plants, Space research instruments

PROCESS CHARACTERISTICS

1) RCC (Resistance capacitor circuit)2) Rotary impulse generator3) Controlled pulse circuit

RCC

Frequency of sparking -

GENERAL CHARACTERISTICS

Material removal rate using RC circuit1) Variation of MRR with resistance

2) Variation with respect to capacitance

4) Variation with Spark F

EFFECT OF EDM1) On metal Surface

2) Fatigue strength