Enhancing Tool Dynamics and Stability in Internal Turning with an Adjustable Clamping Device under Variable Cutting Conditions

This paper presents a novel method for suppressing the vibration of internal turning tools by adjusting clamping conditions. First, an adjustable device, incorporating multiple clamping modes, is developed to shift the tool frequency and improve the tool stiffness and damping. A multitude of clamping schemes can be generated by combining different clamping modes, and these schemes are subsequently quantitatively characterized as a group of multi-sourced boundary constraints. Building upon this foundation, the dynamical model for slender turning tools equipped with the designed device incorporates the effect of flexible boundary constraints. This incorporation is achieved through an inversion method that considers the uniqueness of the solution, facilitating accurate identification. Then, a cutting conditions-dependent adjustment strategy is developed to enhance tool dynamics and turning stability. The simulation results clearly illustrate the device's capability to continuously and effectively adjust tool dynamics over a wide range. Consequently, the optimized clamping scheme can constantly adapt to the variable cutting conditions and the tool stability domain is further improved. Finally, a series of internal turning tests are carried out on difficult-to-machine materials. The experimental results demon-strate the effectiveness of the clamping device and the corresponding adjustment strategy in suppressing tool vibration stemming from various sources, no matter what tool structures and cutting parameters are pre-selected. As a result, the surface quality is improved, and the tool life is extended.