ELECTRIC DISCHARGE MACHINING

AMAN BAKSHI 2013EME09AMIT SUHAG 2013EME10AMITOJ SINGH 2013EME11

CONTENTS

Origin and Introduction Principle of EDM Construction and working Heat Affected Zone Applications Advantages and Disadvantages

Introduction

Principle

Work piece and tool are submerged in a dielectric fluid

Work piece and tool is separated by small gap called spark gap

Gap is kept so the spark can take place and material can be removed from the work piece

The dielectric is replaced after sometime with the help of pump and filter

This principle involves different phases like

1) Application of voltage 2) Formation of plasma channel 3) Discharge phase 4) Collapse of plasma channel

Construction and Working

Components of EDM

Tool and Work piece Dielectric fluid Pump Filter Power source

Plasma generation in EDM

ADVANTAGES1) Conducting materials regardless of

their hardness strength toughness and microstructure can be easily machined

2) The tool and work piece are free from cutting forces

3) Complex shapes can be easily made4) Tool making is easier as it is made

from softer metals5) There is no heating of bulk material6) The chips are being continuously

flushed

DISADVANTAGES 1) Low MRR. 2) The w/p must be electric conductor.3) The surface after machining is highly

stressed.4) Machining time is too long.5) Specific power consumption is too

high.6) It needs further finishing as the surface

finish is not so good.

APPLICATIONS1) It is used in the production of die for

fabrication of all components.2) EDM can be used in manufacturing of

hydraulic valve spools, gear wheels, fine holes or slots in hard blade materials used in gas turbines, compressors, diesel engines etc.

3) It is used in fabrication, extrusion, blanking, stamping and embossing dies.

4) It is also used for machining of harder materials which cant be machined by conventional methods