Ball screw manufacturer It is stated that there are many types of common failures in ball screw mechanisms, and no single, fixed approach can cover them all. Some common failures are gradual and progressive, developing over time as usage duration increases; other times, they occur suddenly, often without any obvious warning signs—emerging abruptly as a result of the combined effects of various adverse conditions and external factors. Therefore, conducting proper inspections to accurately identify the true nature of the failure is a prerequisite for swift and precise maintenance.

　　(a) Inspect and repair the bearing clearance at the ball screw support points.

　　If, when the dial indicator used to precisely measure the ball screw is rotated in both forward and reverse directions, the needle does not oscillate, it indicates that the ball screw has not moved. Conversely, if the dial indicator needle oscillates, it means the ball screw has shifted. The difference between the maximum and minimum readings on the dial indicator represents the radial displacement of the ball screw.

　　At this point, we should check whether the locknut of the support bearing is securely tightened, whether the support bearing itself has worn out or failed, and whether the preload rolling bearing seal ring is properly fitted. If the rolling bearing is in good condition, all that’s needed is to re-install the preload and the load-bearing seal ring.

　　If the rolling bearing is damaged, replace it, re-install the preload seal ring, and then tighten the back cap. The amount of radial movement of the ball screw is typically determined by the precision of the preload seal ring supporting the bearing. Ideally, the assembly precision of the ball screw should result in a clearance—either positive or negative—while the supporting bearing should have a clearance fit of approximately 0.02 mm.

　　(b) Inspection and Maintenance of the Clearance in Ball Screw Double-Nut Assemblies

　　According to the inspection, if it’s confirmed that the common malfunction is not caused by play in the ball screw, then you should pay attention to whether there’s a gap forming between the screw and the nut assembly. The detection methods for these issues are essentially the same as those used to check for play in the ball screw. Use an inside diameter dial indicator to precisely measure the working table connected to the nut. Rotate the ball screw back and forth, and if you detect a significant gap between the ball screw and the bolt, make the necessary adjustments accordingly.

　　(c) Inspection and Maintenance of Single-Nut Assemblies

　　 The ball screw manufacturer stated that, For single-nut ball screws, the clearance between the screw and nut pair cannot be adjusted. If clearance is detected in the screw-nut pair, first check whether the thread arcs on the screw and hexagonal nut are damaged. If there is uneven wear, the entire screw-nut assembly must be replaced.

　　If the damage is minor, you can replace the ball with one that has a larger aperture to address the issue. Examine the maximum clearance in the screw-nut assembly, increase it to match the ball’s diameter, and then select an appropriately sized ball for reassembly. This type of maintenance is relatively complex, time-consuming, and requires high technical expertise.

　　(d) There is no fixed gap between the nut flange and the operating platform.

　　 The ball screw manufacturer stated that, This situation is generally very easy to overlook. Since CNC lathes undergo long-term reciprocating motion, the screws securing the fixed faceplate may become loose. When checking for play in the screw and nut assembly, you should first identify the potential failure factors to avoid unnecessary detours during troubleshooting.