There are obvious layers on the surface of the printed model
1. Check the "anti-backlash nut" of the drive screw, if the screw is loose, please tighten it again.
2. Check whether the fixing screws of the motor are loose, and retighten the screws.
3. Use a dust-free cloth to clean the transmission screw, and then reapply lithium-based grease on the screw after cleaning.
4. If the printer is used intensively (more than half a year), it can be replaced with a new anti-backlash nut.