ELECTROCHEMICAL MACHINING

"A process to produce metallic objects with a technique that is essentially precision electrodissolution. The metal to be machined is made the anode in an electrolytic cell while the cathode (or ""tool"") is made of inert material and is machined to be the ""mirror image"" of the desired shape. A very small gap (typically, less than 0.1 cm) is maintained between the electrodes and a large current density is applied with a fast flowing electrolyte. One of the advantages of this production technique is that very complicated shapes can be produced with a single operation from very hard alloys that would be very difficult, if not impossible, to machine with any other metal cutting technique. Some typical applications are the production of turbine blades and the drilling of holes with very large depth-to-diameter ratio. The cathodic reaction is typically hydrogen evolution. "