Influence of ultrasonic vibration cutting on mode-coupling chatter

This paper analyses the influence of ultrasonic vibration cutting (UVC) on the mode-coupling chatter through both theoretical model and experimental measurement. UVC method can suppress the mode-coupling chatter by decreasing the input energy of a cutting system. On the one hand, there is an energy threshold of mode-coupling chatter for a determined system, which is the integral of cutting power in cutting time. The established critical cutting depth model shows that UVC method can enlarge the critical cutting depth. It means in a shorter cutting time, UVC system can sustain larger cutting power and keep the energy threshold uncharged, maintaining the system stable. On the other hand, under the same condition, UVC method reduces effectively the cutting force and system input energy to suppress the mode-coupling chatter. Experiments have been conducted using the weak stiffness boring bar. The results indicate that UVC method can enlarge the critical cutting depth and the critical cutting depth is in inverse proportion to duty ratio; UVC method can reduce the chatter amplitude and obtain better cutting quality.