Analytical and Experimental Investigation on Cutting Force in Longitudinal-Torsional Coupled Rotary Ultrasonic Machining Zirconia Ceramics

Ceramics and other hard-and-brittle materials are very effectively processed by longitudinal-torsional coupled rotary ultrasonic machining (LTC-RUM). However, the cutting force evolution and the effects of processing parameters on the material removal mechanism in LTC-RUM need to be clarified for machining optimization. This paper proposes a cutting force model of the LTC-RUM of zirconia ceramics via the brittle material removal mechanism. Firstly, the kinematic analysis of a single abrasive grain was performed, with further consideration of the material removal volume, the effective contact time, and the impact force per one ultrasonic vibration cycle. Then, the longitudinal-torsional coupled vibration of the core tool was analyzed from the standpoint of wave energy conversion. The analytical model was finalized and experimentally verified by LTC-RUM tests. The cutting force curves predicted via the proposed model were in good agreement with the experimental results. The results obtained are considered instrumental in predicting the effects of processing parameters on cutting force during LTC-RUM of ceramics and their further optimization.