Spectroscopic Measurement of Electric Discharge Machining for Silicon Carbide

Abstract

Diamond saw is generally used to make the silicon carbide (SiC) wafers from ingots, but it takes long time for cutting. We have used the electric discharge machining (EDM) to cut SiC. The cutting speed of EDM for SiC is almost 10 times faster than the diamond saw, and the surface roughness is 1/10 for the diamond saw. EDM cut SiC by the plasma produced between the wire and SiC material. The emissions from EDM plasma may involve much information for EDM cutting. We monitored the total light intensity by a photodiode, and observed the spectrum of the emission from EDM plasma by a visible spectroscopy. The discharge gas used helium and argon. In both discharges, the light emission was observed when the current was not zero. Also, many lines were observed Si I, Si II and C I from the SiC sample, and Cu I and Zn I from the wire. And, the electron temperature of EDM plasma was estimated to be under several eV because the observed lines were almost the emission from atoms. Also, the scars, which show the copper-alloy wire was hurt by discharge, were observed from the wire.