On-machine measurement method for dynamic stiffness of thin-walled workpieces

Abstract

This paper proposes a novel measurement method for the dynamic stiffness of thin-walled workpieces. The proposed method is called the displacement sensorless piezoexcitation (DSPE) method. The DSPE method uses a piezoelectric shaker attached to a machine tool spindle. Sensor setup on workpieces is not required because workpiece displacement is estimated from the excitation force and input voltage to the shaker. A measurement instrument based on the DSPE method was developed. The measurement accuracy of the DSPE method was verified by comparing its measurement results to those of a conventional piezoexcitation method and impact tests. The experimental results demonstrate that the DSPE method is almost comparable to the conventional methods. Cutting experiments were conducted to analyze the workpiece compliance measured by the DSPE method and the vibration amplitude during cutting. The results demonstrate that the DSPE method can accurately evaluate the dynamic stiffness affecting vibration during the cutting process.