Modeling of contact interactions in lathe turning with accounts for rheology in the cutting zone

This article discusses the dynamic modeling of contact interactions in the technological system of machining in the turning process based on piecewise linear approximation. A feature of the model is that it differentiates between the conditions of contact interaction between the front surface of the tool and the coming off chips, as well as between the back surface of the tool and the workpiece being processed. The consideration is based on the two-term characteristic of friction, realized in the form of a sequence of sliding and adhesion phases. In this case, the process of contact interaction in each phase is described by a set of rheological models. The phase switching conditions are determined by the rate of relative contact interactions, as well as the contact pressures between the front surface of the tool and the chips, between the back surface of the tool and the workpiece. Differentiated description of contact interactions from the front and back surfaces of the tool made it possible to build a tool for studying the processes of self-regulation of contact interactions in dynamic contours and the connectivity between them, which allows us to determine the conditions for the formation of self-oscillations that the dynamic system imposes on itself. The performed experimental studies have shown the correspondence between the nature of the movements during modeling and real cutting.