Effect of tool posture on system dynamics and machining stability in complex surface milling

Abstract

In complex-surface milling, the cutter attitude changes from one tool-path segment to another, so the frequency response function (FRF) of the tool system near the cutting zone is not constant. This point is important in practice because the same spindle speed may lead to different behaviours as the local posture changes. In this paper, the posture effect is described through an equivalent contact-point approach. Abaqus is used to obtain the displacement response for different overhang lengths and inclination angles, and the resulting stiffness, damping, and equivalent mass are then introduced into a single-degree-of-freedom model to build the corresponding FRFs. On that basis, regenerative chatter theory is employed to calculate the limiting axial depth of cut and the associated stability lobe diagrams. The results indicate that a longer overhang lowers the natural frequency and weakens the dynamic stiffness, whereas a larger inclination angle mainly changes the local response level and shifts the stable spindle-speed region. The proposed procedure offers a practical way to connect posture variation with chatter-free parameter selection in complex-surface milling.