Study on Rotor Dynamics Characteristics of High Speed Aerostatic Motorized Spindle during Fly-cutter Milling Process

In the actual machining process, the quality of the machined surface will be reduced due to the vibration of the rotor. A variety of forces can cause the rotor to vibrate. These forces include unbalanced magnetic pulling force, cutting force generated during the machining process, and imbalance due to mass The centrifugal force caused by the distribution. In order to analyze this problem in depth, a study on the dynamic characteristics of the rotor during the high-speed flying cutter milling process of the aerostatic bearing electric spindle was carried out. Considering the above forces, a five-degree-of-freedom rotor dynamic milling model was established, and The calculation formula of the unbalanced magnetic tension is given; the calculation formulas of the translational stiffness, translational damping, angular stiffness and angular damping of the bearing are derived using the linear perturbation method. The rotor dynamics equation is derived using the Newton-Euler equation, And use characteristic equations, system initial conditions, impedance method, state space model and other conditions to solve the problem. The dynamic characteristics of the rotor under empty cutting and discontinuous cutting are numerically simulated. The study found that the movement of the rotor centroid during empty cutting The trajectory changes with the state of motion, and when in a stable state, it appears as a regular circle in the radial direction; during the cutting process, the vibration characteristics of the spindle rotor are affected by the centrifugal force caused by the eccentricity of the rotor mass and the periodic cutting force.