EDM (Electrical Discharge Machining) is a machining process that uses a highly controlled "Spark" to cut metal or most any electrically conductive material.
A Wire EDM is a type of EDM machine that uses a continually feed wire, (typically .010" dia brass wire) as an electrode and is submerged or flushed in dielectric water while cutting. The brass wire electrode will cut the base metal to a very high degree of accuracy (within +/- 0.0001”). The Wire EDM is for straight through cutting applications and can also tilt while cutting for taper cut applications.
Sinker EDM is another type of EDM machine that uses an electrode (typically either graphite or copper) to erode the base metal of the work piece. A Sinker EDM is capable of EDMing pockets or cavities for applications like mold making and also features that can't be machined by conventional methods.
Small Hole EDM Drill is a type of Sinker EDM that uses a small diameter electrode to drill small holes very deep and very quickly through metal.