Material removal mechanism of SiC ceramics by elliptic ultrasonic vibration-assisted grinding (EUVAG) using single grain

Abstract

The variation laws of grinding force, grinding specific energy, material removal rate, scratch morphology, and smooth surface ratio are investigated from the perspectives of wheel speed and undeformed chip thickness to study the material removal mechanism of elliptic ultrasonic vibration-assisted grinding (EUVAG) of SiC ceramics. First, the characteristics of undeformed chip thickness are analyzed based on the trajectory of grain in EUVAG. Then, a comparative experiment of EUVAG and conventional grinding (CG) with SiC ceramics of single diamond-grain scratches is conducted. Experimental results show that EUVAG plays a significant role in reducing grinding force and specific energy, which improves the material removal rate compared with CG. The grinding force is proportional to the undeformed chip thickness, and the grinding force ratio (normal force/tangential force) ranges from 3.8 to 9.8 under CG and from 2.2 to 7.1 under EUVAG. With the increase in wheel speed, grinding force increases first, then decreases, and finally increases again. As a whole, the grinding specific energy decreases with the increase in undeformed chip thickness, and it rises with the increase in wheel speed. The overall decrease in grinding specific energy under CG is more drastic, and the variation range is about three times of that at EUVAG. When the wheel speed is small or undeformed chip thickness is increased, MRR of EUVAG can be increased by about 30% compared with CG. The larger wheel speed and the smaller undeformed chip thickness all have an inhibitory effect on the line broken. The undeformed chip thickness is the primary affecting factor of the smooth surface ratio, followed by elliptic ultrasonic vibration, and the wheel speed has the smallest effect.