Improving processing stability of thin-walled casing workpieces by sucker-mounted TMD: Optimization, design, and implementation

Passive chatter suppression by addition of tuned mass dampers has proven effective in enhancing machining stability of thin-walled workpieces. However, the damper installed on a fixed position may fail to offer effective and robust chatter suppression, as the cutting position varies during machining. This challenge is compounded by the steep dynamics variation of the workpiece along the radial direction caused by material removal in cutting zones. The present paper presents a comprehensive study on improving the chatter stability of milling thin-walled casing workpieces by employing a sucker-mounted damper, which allows a quick and easy repositioning for following the instantaneous cutting zone. An inverse multi-point receptance coupling method is developed to predict the frequency response function of the workpiece equipped with the sucker-mounted damper at the instantaneous cutting position, while accounting for the material removal effect. The damper's parameters are optimized using a new strategy focused on stability lobe diagrams to maximize the chatter-free cutting depth within a specified spindle speed range. This strategy aims to maximize material removal rate while adhering to the constrained speed range imposed by practical processing systems. The structure of damper, which embodies the optimum parameters, is implemented from configuration to dimensions using the screw theory. A series of modal test and milling experiment with and without the damper are conducted to verify the validity and reliability of the sucker-mounted damper. The results indicate that the damper is able to improve the material removal rate by up to 220.0%, and satisfy the requirement of robust performance, flexible repositioning and secure attachment for milling large thin-walled workpieces.