Proper installation and mounting alignment are essential to ensure the rated lifetime, positioning accuracy, and quiet operation of precision ball screw pairs. Even minor angular misalignment or radial loading will induce high contact stresses, causing premature wear and fatigue spalling.
Figure 1: Ball Screw Centerline Parallelism and Bearing Block Alignment
1. Fundamental Installation Rules
- Pure Axial Loading: The ball screw pair must only carry axial forces. Under no circumstances should it sustain radial loads or bending moments.
- Axis Parallelism: Maintain strict parallelism between the ball screw axis and guiding linear rails (recommended within 0.015 mm per 1,000 mm stroke).
- Coaxiality of Supports: Ensure coaxial alignment between the fixed bearing support block, nut bracket, and supported bearing block using dial test indicators.
- Avoid Forcing the Nut: Never impact the nut or screw with hammers. Tighten flange bolts symmetrically in a crosswise pattern.
2. Lubrication and Protective Measures
- Grease Selection: Use high-grade lithium-soap grease (NLGI 1 or 2). In cleanroom and medical environments, specify low-dust fluorinated grease.
- Relubrication Interval: Check grease condition every 3 months or 100 km of cumulative travel.
- Protective Bellows: In environments with abrasive dust, chips, or fluid splashing, always equip the screw shaft with telescopic bellows or spiral spring armor covers.
