As a crucial precision transmission element in modern mechanical equipment, ball screws are widely used in high-precision fields such as CNC machine tools, automation equipment, semiconductor manufacturing, and medical equipment. Mastering the correct maintenance knowledge can not only restore equipment performance in time, but also effectively extend the life of the screw and reduce overall costs.
Fault diagnosis: Find the root cause of the problem
The first step in maintenance is to accurately diagnose the fault. Common ball screw failure phenomena and possible causes include:
I. Abnormal noise (howling, rattling, buzzing):
Poor lubrication/failure: The most common cause is grease drying, deterioration or contamination.
Damage to the ball or raceway: pitting, peeling, indentation, cracks.
Improper preload: Too much preload (loud noise, high temperature rise) or too little (large gap, poor precision).
Foreign matter intrusion: Chips, dust, and impurities enter the nut.
Support bearing damage: Support bearing failure at both ends of the screw.
Resonance: The speed is close to the natural frequency of the system.
II. Jamming or uneven operation:
Severe lubrication or contamination.
Severe damage to the ball or raceway (such as scratches, debris).
Foreign objects are stuck.
The screw is bent and deformed.
The internal components of the nut (such as returner, ball retainer) are damaged.
III. Decreased positioning accuracy/repeat positioning accuracy:
Excessive axial clearance: Insufficient preload, nut wear, ball wear.
Screw bending or improper preload/damage of support bearings.
Insufficient rigidity and looseness of nut mounting seat or bearing seat.
Uncompensated thermal elongation caused by temperature rise.
Uneven wear of raceway.
V. Abnormally high temperature rise:
Excessive preload.
Poor or excessive lubrication.
High-speed operation and insufficient lubrication/cooling.
Improper installation causes additional friction (such as coaxiality difference).
Excessive ambient temperature.
VI. Obvious vibration:
Screw bending.
Support bearing damage.
Poor dynamic balance (especially obvious at high speed).
Damaged or misaligned coupling.
Resonance.
VII. Grease leakage or discoloration:
Ageing, wear or damage of seals.
Severe contamination (grease turns black).
Excessive temperature causes oil to deteriorate.