Essay On Electro Discharge Machining

Electro discharge machining (EDM) is a non-conventional process used in industry for machining various intricate shapes. This process is known for machining hard and brittle conductive metallic materials as it can melt any electrically conductive material regardless of hardness at about 8000-12000 °C. History shows that, in 1770, an English scientist Joseph Priestley discovered that electrical discharge could erode metal. Then another 173 years later in 1943, two scientists Lazarenko and Lazarenko discovered that submerging electrodes in dielectric fluid made it possible to control erosion from electrical discharge. This discovery resulted in the development of the world’s first EDM machines as a non-traditional machining process. Since then

In 1940’s, two Russian scientist, B. R. Lazarenko and N. I. Lazarenko are the first researchers who applied the process on a machine to remove material by controlled erosion through a series of sparks. The couple invented a simple servo controller to make the EDM process more cost-effective by maintaining the gap between two conductors in dielectric liquid that helps in reducing the arcing. The developed controller was the relaxation or RC circuit where it used to be called as the Lazarenko’s circuit. This type of controller is still being used until today in some of the EDM machines in order to obtain near-mirror finish structures. The first EDM machine was manufactured by the “Charmilles” in 1952 for commercial use, where later was presented in the European Machine Tool Exhibition in 1955. “Agie” and “Seibu” are among the first companies that developed the wire EDM machine in 1969 and 1972 respectively. Kurafuji and Masuzawa are the first researchers who applied EDM in micro scale by drilling a hole in a 50 µm thick carbide plate