EDM using two separate dielectric fluids and a system for maintaining segregation of the fluids

摘要

In an electric discharge machining method, a workpiece is subjected to an electric discharge machining at a high working speed using water as the dielectric fluid, and after this, the workpiece is finish-machined using oil as the dielectric fluid. An apparatus for carrying out the method has a feeding system for selectively feeding water or oil as the quenched surface of a workpiece is removed by using water as a dielectric fluid in electric discharge machining (EDM) the dielectric fluid to a machining gap between the workpiece and a tool electrode and a returning device for selectively returning the dielectric fluid used in the machining gap to an oil tank or a water tank.