Effects of ultrasonic vibration cutting trajectories on chip formation of tungsten alloys

Chip morphology has a close correlation with machined surface quality and tool wear in turning process. In the current research on ultrasonic vibration cutting, little is known about the effect of different directions of ultrasonic action on chip formation. In this paper, the effect of ultrasonic vibration on chip formation of tungsten alloy when acting in the direction of cutting speed and cutting depth, respectively, was analyzed by splitting the elliptical trajectory. Furthermore, the advantages of elliptical trajectory machining were also explained in terms of strain rate. The results show that ultrasonic vibration in the direction of cutting depth can effectively suppress the serrated chips and promote the formation of smooth and continuous chips. However, ultrasonic vibration in the direction of cutting speed has the opposite effect. When the tool is superimposed with two-way vibration, the chip morphology formed by the elliptical trajectory is smoother and more continuous. Moreover, it achieves the highest strain rate and the lowest cutting force. Finally, as seen from the experiments of conventional cutting and cutting with variable phase difference, the machined surface roughness decreases with the transition of chip from broken and folded shape to smooth shape. Overall, results of cutting experiment are consistent with simulation results demonstrating the effectiveness of the current work.