EDM (Electrical discharge machining)

• EDM is also known as spark machining, wire burning or wire erosion.

• It is a manufacturing process where desired shape is obtained by using electrical discharges.

• EDM used for machining hard material, which is electrical conductor.

• The work place and tool are separated by gap called spark gap.

Fig. general dig. Of EDM

Applications of EDM :

• Used in automobile industry for drilling small holes in fuel injection nozzle.

• Used for re-sharpening of cutting tools

• Used for producing internal threads

Advantages of EDM :

• No direct contact between tool and work piece, therefore weak material can be machined.

• Complicated shapes can be machined.

• Fine holes can be easily drilled.

• Any hard material can be easily removed.

Limitations of EDM :

• Only electrically conductive material can be machined

• Sharp corners are difficult to produce

• High power require for marching

• Low tool life

Functions and requirements of Dielectric fluid:

• Dielectric fluids – kerosene oil, transformer oil, etc

• Dielectric fluids are used to carry away the removed metal and tool particles.

• It also cools the work piece and act as insulator between tool and work piece.