Assisting Electrode Method for Machining Insulating Ceramics

This paper deals with a new method of machining insulating ceramics by EDM. In this method, a metal plate or metal mesh is arranged on the surface of ceramic insulator as an assisting electrode. The ceramics can be machined very easily with a copper electrode in sinking EDM or with brass wire electrode in WEDM using kerosene as working fluid. Electrical conductive compounds involving cracked carbon from working oil are generated on the surface of the ceramics. It keeps electrical conductivity on the surface of the work piece during the machining. Some examples of machined products with this method are presented. The mechanism of the machining of insulating ceramics is discussed with the principle in the surface modification technique by EDM which has been developed in recent years.