Study on Slicing of Conductive SiC Ingot by Oil and Water type WEDM

Abstract

In this paper, the slicing of a conductive SiC ingot is performed by an oil and a water type WEDM. The machining characteristics by the both type WEDM are investigated. The survey items are volumetric removal rate, average machined groove width, machined surface roughness, and machined surface properties. Regarding the results of the investigation with a discharge current of 1A, the volumetric removal rate of the water type WEDM is about 1.1 times faster than that of the oil type WEDM. Comparing the average machined groove widths, it of the water type WEDM is about 30% wider than that of the oil type WEDM. As a result, it was found that the surface roughness of the machined surface of water type WEDM was about 3 times as rough as the surface roughness of the machined surface of oil type WEDM. The machined surface properties of the both type WEDM are completely different. Specifically, the molten recast layer is hardly seen on the machined surface of the oil type WEDM, but it is clear that the machined surface of the water type WEDM is covered with the molten recast layer. This result suggests that the EDM phenomenon differs between the oil and the water type WEDM. From the above results, it was clarified that the oil type WEDM gives better results than the water type WEDM for slicing of a conductive SiC ingot.