Below is a list of Plunge EDM manufacturers from Chicago, Illinois. Plunge EDM, which goes by many names including conventional EDM, sinker EDM and ram EDM, produces parts by eroding materials in the path of the EDM tool using electrical discharges, or sparks that can generate heat anywhere from eight to twenty thousand degrees. The piece of material to be worked on is connected to a power supply and then an electrode is used to create a conductive path and cut the material into the desired shape or pattern.