CNC EDM (computer numeric controlled electrical discharge machining) is a fully automated process that cuts and drills hard, resistant metals using electrical energy in the form of sparks. The process of electrical discharge machining is able to produce the highly complex and detailed metal products with extremely close tolerances, and with the addition of CNC capabilities, it requires almost no human interaction. CNC EDM is able to cut into electrically conductive metals like aluminum, copper, zinc, tin, titanium, stainless steel, gold, lead, silver, iron and bronze that may be several inches thick. These hard materials are difficult to machine using conventional methods, and therefore EDM machining is of great benefit to many industries which rely on them. EDM provides the most accurate, precise and detailed cuts and drilling to produce parts with smooth, matte edges and no burrs. The aerospace, automotive, metal sculpting, medical, tool and die, military, jewelry, robotics and electronics industries use EDM products like gears, robot parts, mandrels and molds, and stripper plates, among many others. All CNC machinery is equipped with microprocessors and storage units. The machinery works in conjunction with CAD/CAM software which directs the electrodes where to go. There are two main types of EDM - plunge EDM which is able to produce 3 dimensional parts with a copper, graphite, tungsten or brass electrode, and wire EDM which produces 2 dimensional parts with brass electrodes.

EDM machines that are computer numeric controlled are able to guide, monitor and control the whole electrical discharge machinery process. The product design is uploaded into the software, and the design path is carried out by CNC machine components. The computer maintains the wire or electrode movement relative to the work piece, which is tightly clamped down and held secure so it cannot move. The CAD/CAM software then instructs the electrode or wire where to travel, moving within an XY plane. This process is done in a bath of dielectric fluid, which washes away the debris and melted metal, maintains a cooler processing temperature, conducts electricity between the electrode and billet, and prevents premature sparking. Each part is made with exactly the same dimensions and uniformity since CNC machines have a high degree of repeatability. CNC EDM products start out as billets, which are raw metal pieces, and are transformed into parts with acute angles, sharp corners and fine detail. Without computer numeric controls, EDM would be a manual process, and these features would be impossible to obtain. Products would each turn out differently and have a lower degree of accuracy.