Surface morphology of grinding of Si<sub>3</sub>N<sub>4</sub> with cup grinding wheel

Abstract

Grinding parameters affect the morphology of a machined surface. Creep-feed face grinding with a cup wheel is a highly efficient and highly precise grinding method for the manufacturing of hard and brittle materials. There is a trade-off between the rate of material removal and machining precision because substantial material removal necessitates a deep grinding depth that usually results in poor surface quality. The problem of how to machine a high-quality surface while maintaining a high removal rate is therefore important in precision grinding. This paper first introduces this grinding method. Si3N4 is an important engineering ceramic widely used in many fields, and to improve its ground surface quality, an experimental design is established to investigate the relationship between the grinding depth in this method and the ground surface morphology. Making a non-contact optical measurement, the surface morphology is derived and then analyzed. First, surface roughness is investigated for different grinding depths, showing that depth does not affect the surface roughness because the end face of the cup wheel has a regrinding effect. Second, the power spectrum density is investigated, showing that the peaks and valleys of the surface morphology are distributed with increasing intensity as grinding depth increases. Third, the machined surfaces waviness is investigated, and is found to increase with the grinding depth. This is explained by the grinding force increasing with the depth, which intensifies the grinding machines vibration. This paper reveals an important characteristic of this method in that the grinding depth has little effect on the roughness of the ground surface.