CNC machine tools can be divided into two parts: CNC system (CNC) and machine tool. The numerical control system mainly completes the control of the position of the table, the start and stop of the spindle, the commutation, the shifting, the selection of the tool, the replacement, the hydraulic system, the cooling system, the lubrication system, etc. according to the input program. In order to complete the machining of the parts, the machine must perform two major movements: the main motion and the feed motion. In addition to the CNC control, the main motion and the feed motion of the CNC machine tool should have the characteristics of fast response, high precision and high stability in the mechanical structure. This article focuses on the mechanical structure of the feed system. 1. High transmission stiffness The high transmission stiffness of the feed drive system is mainly determined by the stiffness of the screw nut pair (linear motion) or the worm gear pair (slewing motion) and its supporting components. Insufficient stiffness and frictional resistance together can cause the table to creep and cause reverse dead zones, affecting transmission accuracy. Shortening the drive chain, reasonable selection of screw size and pre-tightening of the screw nut pair and supporting parts are effective ways to improve the transmission stiffness. 2. High resonance In order to improve the vibration resistance of the feed system, the mechanical component should have a high natural frequency and appropriate damping. Generally, the natural frequency of the mechanical transmission system should be 2 to 3 times higher than the natural frequency of the servo drive system. 3. Low friction The feed transmission system requires smooth motion, accurate positioning and good fast response characteristics. It is necessary to reduce the frictional resistance of the moving parts and the difference between the dynamic and static friction coefficients. The ball screw nut pair is commonly used in the feed transmission system. 4. Low inertia Since the feed system often needs to be started, stopped, shifted or reversed, if the mechanical transmission has a large inertia, the load will be increased and the dynamic performance of the system will be deteriorated. Therefore, under the premise of satisfying the strength and rigidity, the weight of the moving parts and the size of each transmission component should be reduced as much as possible to improve the ability of the transmission component to respond quickly to the command. 5. No gap Mechanical clearance is another major cause of the reverse dead zone of the feed system. Therefore, the various links of the transmission chain, including: gear pair, screw nut pair, coupling and its supporting components, etc. should be used to eliminate the gap. Structural measures. Leather Glove,Work Glove,Garden Glove,Synthetic Leather Glove Rudong Rizhisheng Safety Products Co., Ltd. , http://www.nt-gloves.com