Design of rotary ultrasonic milling tool using FEM simulation

This study attempted to design a rotary ultrasonic milling tool using finite element method (FEM). The harmonic piezoelectric vibrations of the ultrasonic milling system are simulated by FEM to shed light on the frequency and amplitude of the vibration as well as stress distribution. Results of the study show that the use of FEM in dynamic simulation of ultrasonic milling is feasible. In addition, increase in tool length will result in increase in mass and resonance amplitude but decrease in resonance frequency. During milling, much longer tool may render the tool to withstand a much bigger bending stress, which would likely cause the tool to break or be damaged. However, increase in resonance amplitude can also be achieved by increase in voltage used. Hence, our findings support that a spherical tool of 30 mm long is most suitable for the milling operation. Moreover, to achieve effective conversion of ultrasonic energy for lateral material removal, the milling plane should be enlarged to reduce the milling angle. A good understanding of the efficiency associated with ultrasonic transmission can help achieve fast and accurate design of milling tool.