Dynamic characteristic reconfiguration of a fixture-workpiece system for vibration suppression in milling of thin-walled workpieces based on MR damping fixture

Milling of the low rigidity and large deformation thin-walled workpiece is a critical challenging task due to the obvious machining vibration, which greatly affects the machining accuracy and surface quality of the final part. Compared with the conventional vibration control methods, this paper mainly focuses on suppressing machining vibration by magnetorheological (MR) dampers in milling of the thin-walled workpiece. A novel dynamic characteristic reconstruction strategy of the fixture-workpiece system is proposed to improve the dynamic characteristics of the milling system considering the effect of material removal based on MR damping fixture. Then, the fixture-workpiece system dynamic characteristics reconstruction model is established, subsequently. The time-varying modal parameters in different conditions are iteratively identified, and the stable depth of cut is obtained at any moment. Based on this, the control currents of the MR damping fixture are calculated to offset the change of the damping and stiffness properties of the milling system, which is caused by material removal. Finally, the feasibility and effectiveness of the proposed method are validated by several experiments. Experimental results show that the dynamic properties of the fixture-workpiece system are reconstructed by the MR damping fixture compared with the initial machining state, the vibration response is reduced by 30 to approximately 70%, and the machined surface is improved effectively.