The electro-chemical machining process is based on the principle of electrolysis. An electrode connected to a D.C. source acts as cathode (the tool). The workpiece represents the other electrode and is poled as anode. In a watery electrolyte solution the cathode and workpiece exchange a charge that machines the workpiece – without touching – at the selected point, generating contours, annular grooves, flutes or cavities – all with the highest precision. The material being removed separates from the electrolyte solution as metal hydroxide. Machining is accomplished irrespective of the metal’s microstructure and regardless of whether the material is soft or hard. The components are exposed to neither thermal nor mechanical stresses.