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.

Comparison of slicing-induced damage in hexagonal SiC by wire sawing with loose abrasive, wire sawing with fixed abrasive, and electric discharge machining

“…crystal. To overcome these problems, wiresawing with fixed abrasive (WSFA) and electric discharge machining (EDM) [6][7][8][9] have been developed. The total wafering cost is determined by taking into account the kerf loss, damage depth profile, and wafering time.…”

Characterization of Damage Induced by Electric Discharge Machining and Wiresawing with Loose Abrasive at Subsurface of SiC Crystal

“…The recent expansion of wafer diameter to 6 inches increases cutting time and arises difficulties supplying abrasive grains to the center of over 6 inches crystal. Overcoming these problems, EDM is developed [1][2][3][4]. It is reported that crystal disorder induced by EDM are comparable to that induced by mirror polish [5].…”

Slicing of Rotating SiC Ingot by Electric Discharge Machining

“…Since pure SiC material is expensive and high hardness, researchs for low loss and high speed machining are important. In order to slice a large SiC ingot effectively, EDM as an alternative to the diamond wire saw is studied [1][2][3][4]. Schematic image of the conventional EDM is shown in figure 1(a).…”