The electrode (a highly conductive material such as copper) is processed into the shape to be formed on the workpiece, and a part of the surface is melted by arc discharge to process the workpiece. Normally, this operation is performed with the electrode and workpiece immersed in oil, and precision machining is performed even on difficult-to-cut shapes and high-hardness materials such as carbide.

Extra-fine holes, which are difficult to cut by ordinary drilling, are subjected to electrical discharge machining using electrode tubes (copper or brass). This makes it possible to drill holes in high-hardness materials such as carbide. We realize ultra-precision ultra-fine hole processing with a minimum electrode diameter of 0.02 mm.