Identification of Machining System Dynamics in Internal Turning

When machining high-precision mechanical parts, dimensional accuracy and surface quality are significantly affected by the relative dynamic vibrations between the tool tip and the workpiece. This problem is of particular relevance in internal turning, since the final part of the tooling system is a slender cantilever beam which strongly reduces machining system stiffness. Prediction of the modal parameters characterizing machining system dynamics is a key issue for a proper selection of tooling system configuration and cutting parameters. In this paper, Empirical Transfer Function Estimates of tool tip dynamic compliance with different tooling system configurations are presented. An analytical model describing the behavior of tool tip static compliance, natural frequency and damping coefficient of the dominant mode of vibration is finally proposed and calibrated from experimental data.