CNC machine tool screw is one of the important parts to achieve mechanical movement and precise position control. In daily use, screw accuracy, lubrication and maintenance have an important impact on the operational stability, accuracy and service life of machine tools. Therefore, if a CNC machine tool lead screw is found to be defective, the damaged parts should be repaired or replaced in time to ensure the normal operation and high-precision processing of the machine tool. The following is the common faults of CNC machine tool lead screws collected by the editor and their solutions.
01. Replace screws
1. Replace the screws, loosen the supports at both ends, loosen the saddle fixing screws, and remove the saddle. When loosening screws, protect your hands to avoid injury.
2. The installation sequence is to first fix the screw nut on the motor side, then install the support side nut, adjust the thickness of the screw preload washer to make the guide rails parallel, and finally connect the screw and motor. Install the bolts. saddle.
3. After the installation is completed, it is necessary to measure the shaft runout at the installation end of the motor. If it is within 0.02, it is acceptable; if not, adjust it by tapping the lock nut, and finally tighten the motor shaft to install and tether. Note: When replacing the screw rod, the supporting component must be placed on the workbench under the vertical or tilted axis to avoid damage.
02. The workpiece roughness value is high
1. Insufficient lubricating oil in the guide rail may cause the skateboard to slip. Add lubricating oil to eliminate poor lubrication.
2. If the ball screw is partially rough or worn, replace or repair the screw.
3. If the screw bearing is damaged and operation becomes erratic: Replace the damaged bearing.
4. The servo motor is improperly adjusted and the gain is too large. Adjust the servo motor control system.
03 Large reverse error and unstable processing accuracy
1. The taper sleeve of the threaded shaft joint is loose. Retighten and test again with a dial indicator.
2. The slide plate and pressure plate of the screw shaft are too tight or too loose. Please readjust or repair them.
3. If the temporary tightening force of the ball screw is too tight or too loose, please adjust the temporary tightening force so that the error is less than 0.015mm, and check the axial movement.
4. The preload of the screw support bearing is too tight or too loose: repair and adjust.
5. The manufacturing tolerance or axial movement of the ball screw is large. The control system is used to automatically compensate for the gap, and the equipment is used to measure and adjust the screw movement.
04. Insufficient lubrication of the screw nut
1. Whether the oil separator separates oil: Check whether the oil pipe of the metering oil separator is blocked, remove dirt, and ensure that the oil pipe is not blocked.
2. The ball screw bearing gland is not pressed properly. Adjust the gland so that it presses firmly against the bearing.
3. The ball screw is not lubricated enough. Check the oil separator and oil circuit to ensure adequate lubrication.