A Calibration Ultrasound Method to Estimate Contact Characteristics at Spindle-Holder Interface

Contact parameters of a spindle-holder interface have great influence on the performance of the precision machine tool. However, it is hard to experimentally evaluate the contact parameters. In this paper, a calibration ultrasound method is proposed for contact characteristics measurement of actual 7:24 spindle-holder taper interface. The reflection coefficient of BT 40 type taper interfaces is measured by ultrasonic scanning. A calibration equation is used for contact pressure estimation, and a stiffness calibration equation is further used for contact stiffness estimation. The result was validated by an impact hammer testing. The results show that the surface shape error has a great effect on the contact pressure. The model based on the contact stiffness measured by the presented method can be effectively used to predict the dynamics of spindle system.