EDM: Electrical Discharge Machining Overview
EDM is a curious process developed in the 70's that uses sparks to dislodge atoms of a metal. It is extremely accurate metal removal method but often slower than alternatives. Its accuracy makes EDM a popular technique for mold making. EDM only works with conductive metals, no plastics. There are three common types of EDM; Wire, Sinker, and Hole Popper. We do the first two types.
Wire EDM can be visulaized by thinking of the single-wire cheese cutter common in home kitchens. Whatever this cheese cutter can do in cheese, EDM can do in metal but with extreme accuracy.
Sinker EDM will literally burn a shape into metal. IF one wants a star shaped hole in metal, sinker EDM will "sink" that hole into the metal.
Hole Popper EDM will "sink" tiny holes to a great depth in metal. It will outperforn tradional drilling. It will make holes that were considered impossible with drill bits.
For percision and accuracy, other metal removal processes shear or shave metal off and require a very stout machine structure to brace against. EDM by using sparks does not push on anything and thus can be done with a less massive machine and much more accurately.
Video is 30 seconds of wire EDM cutting under clear water. Towards the end, the spool of spinning brass wire is the electronic knife if you will. The wire is used once and recycled. The water is purified tap water so that it will act as an insulator & coolant.