Investigation of Finite Amplitude Stability Due to Process Damping in Milling

Finite amplitude stability due to process damping is an intermediate state between fully stable and fully unstable vibrations in machining. In this state, the amplitude of vibration increases and stabilizes at a certain magnitude before the tool disengages from the cut. In the literature, this phenomenon has been studied experimentally and by conducting numerical simulations in turning, but to the best of our knowledge, it has not been reported in milling. In this paper, the existence of this phenomenon in milling is investigated experimentally and numerically. In addition, an amplitude-dependent formulation of process damping is integrated into the Semi Discretization Method of computing stability lobes to determine the borders of finite amplitude stability region in milling. Both the experimental evidence and numerical simulations showed the finite amplitude stability to also occur in milling. Moreover, the accuracy of the presented Semi Discretization Method in the prediction of finite amplitude stability region is verified by the experimental results and numerical simulations.