Technological Experiment and Regression Analysis of Surface Residual Stress in Ultrasonic Grinding

In order to explore the process features of ultrasonic grinding, an experimental investigation was conducted on 45 steel using a self-developed axial ultrasonic grinding apparatus, and the surface residual stress of workpieces was measured using an iXRD residual stress analyzer. Based on the experimental results, influences of grinding process parameters on the residual stress were analyzed, and regression equations of residual stress against the grinding depth, the ultrasonic vibration amplitude, and the circular linear speed of the grinding wheel were established, with which the residual stress was predicted. Results show that residual compressive stress is produced in workpiece surface in both the ordinary grinding and ultrasonic grinding, and the residual stress in the axial direction is significantly greater than that in the grinding direction. In addition, the residual compressive stress increases with an increase in grinding depth and ultrasonic vibration amplitude, but decreases with an increase in the circular linear speed of the grinding wheel. The maximum relative error between the predicted value and test value is less than 5%, which proves that the predictive regression model can effectively predict the surface residual stresses in ultrasonic grinding.