Experimental dynamic modelling of peripheral milling with process damping, structural and cutting force nonlinearities

In this paper, an extended dynamic model of peripheral milling process including process damping, structural and cutting force nonlinearities is presented. Cutting forces are described through a third-order polynomial function of chip thickness while a cubic nonlinear function is considered for the structural stiffness. Under stable and regenerative chatter conditions and using Fourier series components, closed form expressions for the nonlinear cutting forces are derived. Parameters of the proposed model are identified through a set of experiments. For this purpose, modal experiments and measurement of cutting forces (at various feed rates) are performed to determine the modal parameters and the coefficients of nonlinear cutting force model. In addition, coefficients of the structural stiffness and process damping are identified through the analysis of experimental and simulated stability lobes diagrams. Simulated stability lobes diagram is constructed based on two approaches: a trial and error (TE) based algorithm and semi-discretization method (SDM). The presented experimental method for model identification can be implemented on any industrial milling process.