Wire EDM is a process, which consists of wire .006 inch to .008 inch in diameter. It is electrically charged at a very high voltage and used to cut precision shapes in prismatic components. The wire passes from one spool to another and is guided by an upper and lower guide as it cuts. The advantages to wire EDM machining, includes the ability to cut nearly square internal corners and tapers that would be virtually impossible to cut otherwise. The upper guide and lower guide can move independently thus cutting one geometric pattern on tap of a part and another geometry on the bottom of the part. These machines are CNC controlled. It is typically performed by machine shops. It uses rapid, controlled and repetitive spark discharges.