by a series of rapidly recurring electrical discharges between an electrode (the cutting tool) and the workpiece in the presence of a dielectric field. The ensuing minute metal chips...., and 20" thick. Definition of EDM EDM - Sinker Electrical discharge machining (EDM), sometimes referred to as spark machining, is a nontraditional method of removing metal... literally "sinks" a required shape into the workpiece. Wire EDM Wire electrical discharge machining (WEDM), also known as wire-cut EDM is a process of using a thin single-strand of metal...