Modelling chatter stability in boring operations

This article presents a model that explains the behavior of slender boring bars when machining with cutting depths smaller than the nose radius of the insert. Unlike earlier models, this model correctly predicts that the instability increases with smaller cutting depths and feed. The coupling between vibration amplitude and cutting force is described by a simple analytical model taking into account the nose radius, cutting depth and feed, while the coupling between tangential and radial cutting forces is described by an empirical model based on cutting force measurements. By incorporating these models into a small signal feedback model we find the stability criteria for chatter-free machining in steel.