Electro Discharge Machining, Working Principle Advantage & Disadvantage

Electro Discharge Machining (EDM)

In this article, we will learn about Electro Discharge Machining, Working Principle Advantage & Disadvantage. It is also known as Spark Erosion (or) Electro Erosion machining. This method is used to create complex-shaped tools. Stamping tools, extrusion, and forging dies are used to remove metal from the workpiece in erosion mode. Erosion is caused by the spark that forms between the workpiece and the tool.

Working Principle

The workpiece is captured in the fixture and placed inside a tank. The tank is filled with die – electric fluid. Kerosene, mineral oil, white spirit, and paraffin are used as dying electric fluids. Die Electric fluid does not transmit electricity.

The work piece is connected to the + ve terminal of the DC supply. The Tool is positioned vertically on top of the work piece. The tool is made of metal such as copper, yellow brass, zinc (or) graphite. Then will be in a hollow form. It is attached to the –ve terminal and acts as a cathode.

Between the tool and the work, the piece should be 0.05 mm to 0.00. Through this gap die – electric Ruid is applied to the fluid with high pressure. When supplying a DC supply, an electric spark occurs between the tool and the work piece. This spare produces more heat (1200 ° C). This heat will melt the surface of the work piece and cause the Tool shape in the work piece. Tool’s + ve terminal tool will reduce browsing.

The Servo mechanism is used to feed the tool and maintain it between the tool and the workpiece. Die electric fluid is also used as a coolant. It carries the extruded metal. This fluid is also used as an insulating medium. Applications Nozzles are used to make small holes. Mold cavities can be created. Press tools and die.

Advantages

• All metals that transmit electricity can be machined.
• Machining can be done for 0.2-micron accuracy.
• No stress in the work piece.
• It does not affect the mechanical properties of the metal during machining.

Disadvantages

• We need more electricity.
• It is impossible to machining electrical conductors.
• The tool gets higher depreciation.
• Severe corners cannot be made.