Known by many other names, including spark machining, arc machining and (inaccurately) burning, the EDM process is conceptually very simple: an electrical current passes between an electrode and a workpiece which are separated by a dielectric liquid. The dielectric fluid acts as an electrical insulator unless enough voltage is applied to bring it to its ionization point, when it becomes an electrical conductor. The resulting spark discharge erodes the workpiece to form a desired final shape.