EDM machining, also called spark erosion or electrical discharge machining, removes metal using controlled electrical sparks between an electrode and the workpiece. There is no cutting force, so it is useful when thin walls would deflect, when features are delicate, or when the material is too hard for practical milling.
Common reasons buyers specify spark erosion service include:
EDM machining is also a smart option when you want to avoid rework. For example, if a milled pocket leaves a radius that breaks fit, sinker EDM can hold the geometry without forcing a design change.