According to Norman Noble Inc., in Highland Hts., Ohio, (nnoble.com) EDM vaporizes material instead of cutting it, so the process suits materials with a hardness above Rc 38, such as Stellite, hardened steel, and tungsten carbide. EDM works well to make parts with thin walls, recessed cuts, and complex shapes. The process has many advantages on such applications, says the company. For one, the wire or electrode doesn't touch the part, so it applies no force and there is no deformation. Small parts are easy to fixture because EDM generates no stress or vibration. And because the electrodes don't rotate, it's simple to produce non-round cavities and openings. The company says it uses wire, plunge, and conventional EDM to manufacture parts with critical dimensions and tolerances, as well as finish premachined pieces to exact dimensions. The latter can involve waterjet roughing before EDM to cut time and costs.