Study on material removal mechanism and surface formation characteristics of reaction-bonded silicon carbide by electrical discharge grinding technology

Abstract

Electrical discharge grinding technology (EDGT) is an efficient and high precision method for machining RB-SiC ceramic materials. In this paper, the mechanism of material removal in EDGT is deeply studied, and the formation characteristics of surface topography under different material removal methods affected by grinding depth are analyzed. A three-dimensional heat conduction analysis model in the process of single pulse discharge was established, and the temperature field distribution in RB-SiC ceramic material under different discharge energy was obtained by numerical calculation. It is found that the simulated crater radius and depth increase with the increase of the discharge time, and the material removal amount gradually increases, but the growth rate gradually decreases. In order to give full play to the advantages of EDGT, the discharge energy and grinding depth were optimized according to the material removal mechanism. Finally, RB-SiC ceramic machining experiments were carried out using the optimized machining parameters, and a smooth surface with few discharge craters was obtained. It is found that the grinding scratches on the material surface are mainly plastic grinding, and the material surface roughness is 0.443 µm. The research results of this paper can provide guidance for engineering practice of ductile grinding technology of RB-SiC ceramic materials.