The influence of supporting force on machining stability during mirror milling of thin-walled parts

Mirror milling has been regarded as an effective way for large monolithic thin-walled parts machining. However, the supporting force not only improves the stiffness of the cutting point but also affects the dynamic behavior of the machining system. Essentially, the influence mechanism of supporting force on the mirror milling stability should be analyzed. Firstly, a 3-DOF dynamic system model has been developed considering the supporting head-workpiece interaction during mirror milling. And then, the evolution of modal parameters of thin-walled parts under different supporting forces is investigated with a series of impulse harmer tests, which will supply the dynamic parameters for the mirror milling stability lobes prediction using the full-discretization method. On this basis, the optimum supporting force can be determined according to the relationship of the limited cutting depth and the supporting force. At last, the analysis resulted was verified with a series of mirror milling slot test. From the comparison, the optimum supporting force could maintain the stable mirror milling and avoid excess deformation simultaneously.