Stability Analysis of Chatter in Gun Drill Rods Considering Bending Anisotropy

This paper introduces bending anisotropy of gun drill rods, caused by asymmetric cross-section, into chatter stability analysis. A dynamic model considering different stiffnesses along the two principal inertia axes is established. The Galerkin method and semi-discretization method are used to solve the governing equations and generate stability lobe diagrams. Parameter sensitivity analysis shows that drill rod length and material damping coefficient are high-sensitivity parameters, while coolant hole size and eccentric position are low-sensitivity ones. The results reveal the mechanism of bending anisotropy on stability and provide theoretical guidance for chatter suppression in deep-hole machining.