Consolidated chatter stability prediction model considering material removing and ploughing processes

Abstract

A novel consolidated model is proposed to realize the analytical prediction and better understanding of the critical stability determined by regenerative chatter, frictional chatter, process damping, rake angle fluctuation, and ‘mode coupling’ (mentioned by Tlusty), in which the material removing and ploughing processes are considered. In the history, frictional chatter and process damping have been modelled separately and differently, which has impeded the complete understanding of the effect of the ploughing process fluctuation. In contrast, the two phenomena are uniformly and simply formulated in the proposed model, where the ploughing process fluctuation acts as either an excitation or damping effect depending only on the vibration direction and the direction of the dynamic ploughing force. Furthermore, it is consolidated with the regenerative effect, the fluctuation of the rake angle, and ‘mode coupling’ which also affect the actual cutting process. According to the proposed model, the relation between the vibration direction and the direction of the dynamic forces is clarified which makes it possible to better understand the multiple self-excitation/damping phenomena and their effect against the chatter stability. The proposed model is verified through analytical observations and cutting experiments.