Investigation of Polishing Force in Ultrasonic-Assisted Magnetorheological Shear Thickening Polishing: Theoretical Model and Experimental Validation

Ultrasonic-assisted magnetorheological shear thickening polishing (UAMSTP) is a hybrid technique for ultra-precision machining. A polishing force model was developed to elucidate the underlying mechanical mechanism. Based on the harmonic relationships of the ultrasonic vibrations, spindle speed, and feed rate, the velocity field was established. This velocity field, in conjunction with the magnetization pressure, was then used to determine the polishing pressure. A model of the normal force was subsequently established. Taking into account the effects of polishing pressure and ultrasonic vibration, a model for the tangential force component of an individual abrasive particle was established. A tangential force model was developed by vector superposition of the tangential force components. The model was experimentally validated by various abrasive particle sizes, ultrasonic vibration frequencies, feed rates, spindle speeds, working gaps, and with and without ultrasonic vibration. The normal force model demonstrated an average error of 9.82%. The tangential force model demonstrated an average error of 9.05%. This study provides theoretical reference for refining polishing parameters and enhancing polishing quality in UAMSTP.