Ball Screw Repair
There are many instances where a ball screw would need to be repaired. Overtime wear and tear can wear down the metal to a point the machine can no longer function at an optimal level. Additionally, the ball screw can acclimate build-up over time. Many times ball screws require repair when a machine crashes and bends the screw. Choosing to repair or replace may be a difficult decision for many companies. Due to cost and time saved, many companies choose to repair.
Assessing the Damage
Ball screws will typically show physical signs of damage. When assessing a ball screw, it is important to look for cracks, dents or physical breaks. Additionally, if a machine stops preforming at optimal performance, it may mean a worn-out or damaged ball screw. If the screw is worn out, the backlash will increase and efficiency will decrease. Which causes the screw to require extra torque or horsepower in order to turn. When the screw is worn out, the lead accuracy could be worse than required.
Types of Repair
- Level 1: Addresses the most common problems, such as loss of repeatability due to wear. Balls are the first to wear. During repairs, new, larger balls are used at every level to restore preload and repeatability.
- Level 2: Involves regrinding of the ball nut to the steps taken in Level 1.
- Level 3: Adds regrinding of the ball screw threads, and as required, rebuilding of the journal diameters with eutectic spraying and grinding them back to size.
- Level 4: Adds regrinding of the ball nut and ball screw. This level is the most costly. But can restore a damaged ball screw to a normal new screw lifespan.
What to Consider
When looking for a repair service, it is important to keep a few considerations in mind. Such as if the facility has adequate stock of the replacement ball screws that your company uses. It is also important to consider how specialized the operators are. Accessibility to a metals lab and ISO 9000 registration are pluses that will help ensure that your decision to repair is a profitable one. Additionally, repair services should provide a one-year warranty and a certification of the ball screw spring rate, straightness, and squareness of related mounting surfaces.