Three-dimensional stability modeling method for orthogonal turning-milling machining of helical endmill

The invention discloses a three-dimensional stability modeling method for orthogonal turning-milling machining of a helical endmill. The three-dimensional stability modeling method comprises the following steps: (1) simplifying a machine tool-cutter-workpiece system into a mass-spring-damper connected vibrating system, establishing a coordinate system xFyFzF, and establishing a kinetic equation of the vibrating system; (2) carrying out a hammering method modal test to obtain a frequency-response function of the vibrating system in each of xF, yF and zF directions, identifying the modal mass, the rigidity and the damping of the vibrating system, and calculating the inertia force, the spring force and the damping force of the vibrating system; (3) calculating a dynamic cutting force of the helical endmill; (4) solving the kinetic equation of the vibrating system to obtain a stability lobe graph of the vibrating system. The three-dimensional stability modeling method disclosed by the invention gives consideration to the three-dimensional dynamic cutting force of a circumference edge and a bottom edge of helical endmill, and simultaneously gives consideration to the dynamitic characteristics of a cutter side and a workpiece side, so that the stability modeling method is more accurate.