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Modelling of regenerative and frictional cutting dynamics

Abstract:

As most investigations of regenerative and frictional cutting chatters have been performed separately up to now, this paper aims to bridge the gap between the two sources of cutting instability by a new simple one degree-of-freedom (DOF) model involving both time-delayed regenerative effect in chip thickness and Stribeck effect in frictional velocity. In addition, process damping introduced by the interaction between workpiece material and tool's flank face is included as well for the discussion of cutting stability in low-velocity zone. By comparing with other results, it is validated that the new model with Stribeck effect improves the pbkp_rediction of linear cutting stability in the low-velocity zone. Then the influences of friction on the linear stability is extensively investigated, which shows that a small coefficient of static friction and a large Stribeck velocity benefit the cutting stability in low- and intermediate-velocity zones. In addition, linear analysis of the cutting geometries proves that large shear and rake angles can improve the cutting stability as well.