How We Fixed a CNC Machine with Ball Screw Bearing Failure

Overview

This case study highlights how we diagnosed and repaired a ball screw bearing failure in a CNC machine that was causing production downtime, loss of accuracy, and high maintenance costs.

By identifying the root causes and implementing targeted solutions, we significantly improved machine performance and reduced annual maintenance expenses by over $35,000.

The Problem

A customer reported that their CNC machine was making grinding noises and losing cutting accuracy during operation. This led to:

• Unplanned downtime
• Lower product quality
• Increased repair frequency

After inspection, we identified the issue as a failed ball screw bearing, a key component for smooth and precise machine movement.

Root Cause Analysis

We found three main reasons for the bearing failure:

1. Wrong Lubrication

The grease used was too thick, which prevented proper lubrication and caused metal-to-metal contact.

2. Poor Installation

Measurements showed the bearing was not aligned correctly during installation, leading to uneven wear.

3. Contamination

Metal dust from machining operations entered the bearing housing, acting like sandpaper on moving parts.

The Solution

To fix the problem and prevent future failures, we took the following steps:

✅ Improved Lubrication:

• Switched to the manufacturer-recommended grease
• Installed automatic lubricators to ensure consistent lubrication

✅ Precision Reinstallation:

• Used laser alignment tools to install the bearing correctly
• Retrained technicians on best practices for installation

✅ Enhanced Contamination Control:

• Added protective covers to block dust entry
• Installed magnetic chip collectors to trap metal particles
• Set up regular cleaning and inspection checkpoints

Results After Repair

✅ Total Annual Savings: Over $35,000 in downtime and replacement part costs
✅ Improved Production Efficiency and product quality restored

Key Takeaways

For maintenance teams and engineers, this case offers valuable lessons:

• Always use the correct type of grease recommended by the manufacturer.
• Invest in precision tools like laser alignment systems for accurate installation.
• Keep bearings clean — install and regularly inspect sealing components.
• Pay attention to unusual sounds or vibrations — they are early signs of potential failure.

Why This Matters for Your Business

Preventive maintenance and correct installation of ball screw bearings can help avoid costly breakdowns and extend equipment life. This real-world example proves how small changes can lead to big savings and long-term reliability.

If you're experiencing similar issues with your machinery, we can help. Contact us today to learn more about our precision bearing solutions and maintenance support services.