Surface formation mechanism in ultrasonic vibration assisted grinding dental zirconia ceramic process considering stochasticity of grits

Ultrasonic vibration-assisted grinding (UVAG) has been proven to be an effective machining method that could improve the surface quality of hard-to-machine materials. However, due to the uncertainty of the contact between the grits and material, the surface formation mechanism is still worth investigating. In this paper, the surface morphology prediction model of dental zirconia ceramic in UVAG was proposed, which considered the stochasticity of grits. The results showed that the prediction model developed in this paper can well predict the UVAG surface morphology of dental zirconia ceramic. And the error rates of surface roughness and waviness were confined within 13 %. The statistics analysis also had been discussed to support the conclusion. In addition, the increase of ultrasonic frequency and ultrasonic amplitude both can improve the surface quality. It is attributed to the fact that these factors change the trajectories of grits to increase the interfering effect. However, when ultrasonic frequency and ultrasonic amplitude exceed the thresholds, the surface roughness is hardly improved. Therefore, from the point of view of cost and economics, the choice of ultrasonic parameters could be chosen to an appropriate value to reduce the costs.