Machining performance and surface integrity of SiC ceramic machined using electrical discharge milling and the mechanical grinding compound process

A new combined process that integrates electrical discharge milling and mechanical grinding is presented. The process is able effectively to machine a large surface area on SiC ceramic with a good surface quality and low cost. The effects of machining conditions on the material removal rate, relative electrode wear ratio, and surface roughness were investigated. The surface microstructures machined by the new process were observed by a scanning electron microscope (SEM), an X-ray diffraction, and an energy dispersive spectrometer. The SEM micrographs show that the surfaces machined at rough machining mode and semi-finish machining mode are characterized by an uneven fusing structure, globules of debris, shallow craters, and micropores; the surface machined at finish machining mode is smooth, and covered by fewer little craters and pockmarks.