Investigation of Process Damping Effect for Multi-mode Milling Systems

Process damping acts as a significant cause of increased stability in milling particularly at low cutting speeds, which has been studied only for single-mode systems in the literature. Chatter frequency, which depends on the component causing chatter, strongly influences process damping coefficient, which is expected to vary with modes of the system. In this paper, the effect of process damping on chatter stability is investigated considering multi-mode dynamics of the system. The process damping coefficients are simulated for the fundamental chatter frequency of each significant mode and then used in the stability solution in frequency domain. An iterative milling stability solution is used as the process damping coefficients depend on the cutting depth. The stability lobe diagram is constructed with respect to multiple mode characteristics of the system. The theoretical predictions are verified through representative experimental cases and the results are discussed.