The indexing accuracy and accurate stopping accuracy of the electric spindle system of compound CNC machine tools are important indicators for assessing the accuracy of the machine tool spindle and are important factors affecting the machining accuracy of the machine tool. During operation, the rotation of the motor rotor drives the spindle to rotate. The speed loop and position loop of the spindle rotation use high-precision feedback elements to achieve full closed-loop control. The position signal collected by the feedback element is processed by the CNC system to achieve a resolution of spindle indexing of 0.001° or less, so that the spindle system of the turning and milling compound CNC machine tool has very high indexing accuracy and accurate stopping accuracy. In order to achieve high indexing accuracy and accurate stopping accuracy of the electric spindle system, the international turning and milling compound machining centers all use built-in spindle motors, and the spindle and motor rotor are assembled as one, reducing the influence of the intermediate transmission link on the spindle accuracy. Precision preservation solution:
- The motor rotor and the machine tool spindle adopt a special assembly process to ensure the connection stiffness between the machine tool spindle and the inner hole of the motor rotor, and can transmit large cutting torque
- The electric spindle group adopts a higher level of high-speed dynamic balance when assembling, reducing the residual imbalance of the spindle group and ensuring the stability of the spindle during high-speed rotation. The electric spindle system adopts a spindle brake and damping device. When the spindle needs to stop milling or drilling, the spindle is in a braking state to ensure that the spindle does not shake during milling. During continuous indexing milling,
- The spindle is in a damping state to ensure the stability of the spindle rotation during milling. The braking state and damping state can be automatically switched and set by programming.
