Electric Discharge Machining for Silicon Carbide and Related Materials

Abstract

In order to cut the ingots and slabs of the silicon carbide (SiC), we developed the new method of electric discharge machining (EDM). EDM is usually used for the machining of the metals, and if it is electric conductive material, it is effective for the machining. However, if the electrical resistivity of SiC is high, the electric current cannot be large enough for and the EDM, and we failed the machining of SiC. Therefore, we use three methods to keep higher electric conduction. One is photoconductive, the second is high electric field effect and it is called avalanche effect, and the third is high temperature effect because usually the resistivity is low when the semiconductor or insulation materials are in high temperature. Thus, we applied three method, and finally can cut the SiC slabs of the resistivity of the order of 10 Ωm, which is almost 1000 times higher than that of the ordinary EDM at least. The flatness of the cutting surface is the same of the metals’ and the cutting rate for the SiC ingots is 10 times higher than that of diamond saw. This technique will be effective for the related materials of SiC, such as diamonds and GaN.