Requirements of CNC machining center for feed motion
by：QY Precision 2020-03-31
The feed motion of CNC machining machine is the direct object of digital control, regardless of point control or contour control, the final dimension accuracy and contour accuracy of the workpiece are affected by the transmission accuracy, sensitivity and stability of the feed motion. Therefore, the feed system of CNC machining machine tools should pay full attention to reducing friction resistance, improving transmission accuracy and rigidity, eliminating transmission clearance and reducing inertia of moving parts. 1. Reducing friction resistance in order to improve the rapid response performance and motion accuracy of the CNC machine feed system, the difference between friction resistance and dynamic and static friction of the moving parts must be reduced. In order to meet the above requirements, ball screw nut pair, static pressure screw nut pair, rolling guide rail, static pressure guide rail and plastic guide rail are generally used in the CNC machine feed system. While reducing the friction resistance, it is also necessary to consider that the transmission components should have proper damping to ensure the stability of the system. 2. To improve the transmission accuracy and rigidity, the transmission accuracy and rigidity of the feed transmission system mainly depend on the transmission clearance, screw nut pair and worm pair (Circular feed)The accuracy and stiffness of its supporting structure. The transmission clearance mainly comes from the transmission gear pair, the worm gear pair, the screw nut pair and their supporting parts. The pre-tightening force should be applied or measures to eliminate the clearance should be taken. Shortening the transmission chain and setting the deceleration gear in the transmission chain can also improve the transmission accuracy. Increasing the diameter of the lead screw and applying pre-tightening force to the lead screw nut pair, supporting parts and the lead screw itself are effective measures to improve the transmission stiffness. Insufficient stiffness can also lead to Workbench (Or tow board)Produce crawling and vibration. 3. Reducing the inertia of moving parts has an impact on the starting and braking characteristics of the servo mechanism, especially for parts operating at high speed, the inertia has a greater impact. Therefore, on the premise of satisfying the strength and rigidity of the components, the mass of the moving components should be reduced as much as possible, and the diameter and mass of the rotating components should be reduced to reduce the inertia of the moving components.