Continuum model based chatter stability prediction for highly flexible parts in turning process with accurate dynamic force modeling

Abstract

Abstract Stability analysis is rather important in the turning process for achieving a high machining efficiency under the condition of without compromising the surface integrity. However, the occurrence of chatter is not simply attributed to the cutter or the part, and sometimes may be alternating. In this paper, a new chatter stability model is built for the turning process of a typical step shaft with the consideration of the 2-dimensional (2D) compliance of tool and part. Among the model, an accurate dynamic force modeling method is first presented, into which the tool nose radius, the size effect, and the effect of vibrations in chip thickness and width directions are incorporated simultaneously. Then, the position-dependent vibration equations of the 2D compliant turning system are formulated based on the continuous Timoshenko beam theory, and position-dependent modal parameters are subsequently derived by using a matrix recursion algorithm. Further, the dynamic equations for the 2D tool-workpiece compliant system are solved with an extended second-order semi-discretization method. Finally, the simulations and experiments are conducted to verify the built model. The results of stability prediction show a good agreement with the experimental results no matter the flexibility of the cutter or the part plays a dominant role in the turning process.