Stability analysis of pocket machining with the spiral tool path using the discontinuous Galerkin method

Pocket machining is widely used in the aerospace and automotive industries. The spiral tool path ensures smooth and consistent pocket machining. However, high-efficiency pocket machining places great demand for the stability of the milling processes. In this paper, the mechanics and dynamics of pocket machining along the spiral tool path are modeled, and a time-domain method is proposed to predict the stability of pocket machining in the framework of the discontinuous Galerkin method (DGM). The mechanics of pocket machining is modeled on the basis of computing the varying cutter-workpiece engagement. The cutting forces are predicted and experimentally verified. Further, the dynamic model of pocket machining is established and the stability of the pocket machining process is predicted with the stability lobes of representative feed directions along the spiral tool path. The DGM based time-domain method is proposed to improve the computational accuracy and efficiency of the stability analysis. The predicted stability of pocket machining along the spiral tool path is validated by the experimental results.