Study on the Low-Damage Material Removal Mechanism of Silicon Carbide Ceramics Under Longitudinal–Torsional Ultrasonic Grinding Conditions

In order to achieve the high-performance machining of silicon carbide (SiC) ceramics, longitudinal-torsional ultrasonic vibration (LTUV) was introduced into precision machining, and a systematic investigation into the effects of various process parameters on the critical cutting depth and surface quality was conducted. This investigation was undertaken with a view to exploring the ultrasonic vibration-assisted grinding mechanism of SiC ceramics. Firstly, the kinematic model of single abrasive grain trajectory and the maximum unaltered cutting thickness during longitudinal-torsional ultrasonic vibration-assisted grinding (LTUVG) was established to explore its unique grinding characteristics. On this basis, the theoretical modeling of critical cutting depth in SiC ceramics under LTUVG conditions was developed. This was then verified through longitudinal-torsional ultrasonic scratching (LTUS) experiments, and the theoretical analysis and test results prove that compared with normal scratching, the quality of SiC grooves are significantly improved by means of LTUS. During LTUS experiments, the dynamic fracture toughness, strain rate of SiC, and high-frequency ultrasonic excitation significantly enhances SiC performance, increasing the critical cutting depth and expanding the plastic removal region, so it is easy for LTUVG to yield the better surface quality in machined SiC ceramics, which provides important scholarly support for achieving the low-damage machining of SiC ceramics.