Milling chatter suppression for thin-walled part using rotary passive damper with tunable stiffness

Chatter is caused due to the poor rigidity of thin-walled parts during their milling process, so it is difficult to ensure their machining quality and efficiency. Here, a novel rotary passive damper possessing variable stiffness was designed with its natural frequency changed through rotating the damper orientation. The design sizes were determined based on the vibration reduction theory and the finite element (FE) simulation.The modal tests for thin-walled parts were performed, then the damper's optimal installation angle for chatter suppression of thin-walled parts milling was determined for milling processing frequency to avoid parts' modal frequencies. Finally, the chatter suppression effect was verified with milling tests. It was shown that when the damper orientation is 80°, the amplitude of the system's FRF drops to 9.8% of that without the damper; the optimal chatter suppression reaches when the damper orientation is 20°, the amplitude of the system's FRF reduces to 13.6% of that when the damper orientation is 80°, the critical stable cutting depth of thin walled parts with no chatter increases by 1.8 times.