Electrical spark erosion, also known as electrical discharge machining and electrical corrosion machining, called electrical discharge machining in Japan and electrical corrosion machining in the former Soviet Union. It is a method of processing the metal workpiece by utilizing the phenomenon of electric corrosion generated during the pulse discharge between the two poles (electrode and workpiece, should be conductive). Academically it belongs to the category of electrophysical processing. EDM technology is one of the most important parts of special machining technology.