Productivity Tip: How to Achieve Maximum Bearing Life

A few weeks ago, we heard from a customer in the field that one of their bearings failed after only ten days of operation, and they were concerned that the lubricant was at fault.

After some investigation, we confirmed the lubricant wasn’t to blame, but the inquiry reminded us that it might be a good time for a refresher on maximizing bearing life.

So, this week’s tip looks at best practices to help keep bearings operating reliably over the long run.

Maximum Bearing Life

Every bearing has a maximum service life. The trick is in achieving it. Some of the basics required to achieve maximum bearing life include:

  • Proper bearing selection: The bearing must be right for the application. More specifically, it must be able to support the required loads, sustain the desired speed, and withstand environmental considerations. Remember, loads are often on several axes. Make sure the bearing type supports these impingements.
  • Correct installation and alignment: If a bearing is not mounted correctly, it will fail shortly after installation. It’s essential to use proper tools and methods when installing a bearing. Contrary to popular opinion, a hammer is not a proper bearing mounting tool. Alignment is also essential to distributing the load. If not properly aligned, the load will shift or increase, resulting in additional friction and vibration and eventually causing premature fatigue failure.
  • Proper lubrication: Includes greases and oils, lubrication frequency, duration, and application method.
  • Basic condition monitoring: Proper condition monitoring is necessary to deliver maximum life. A good monitoring program establishes baselines and records any changes, including for factors such as temperature, vibration, and more. Good programs also incorporate visual inspection and routine lubricant analysis. Use root cause failure analysis to review each and every bearing failure – and take the lessons learned.
  • Proper removal and replacement: Eventually, a bearing will fail, and it is important that the bearing be removed correctly without damaging the machine’s permanent parts. If, for example, you damage a shaft when removing a bearing, the imbalance created will affect the new bearing installation. Use proper dismounting tools and methods when removing and replacing a bearing.

How relevant are these six factors in enabling maximum bearing service life?

Well, according to SKF, bearings fail for the following reasons:[i]

  • Poor fit: Causes 16% of bearing failures, and this is often caused by maintenance and alignment practices.
  • Poor lubrication: Causes 36% of bearing failures. This is not the same as lubricant failure. If a lubricant is appropriate for the application and also applied at the correct method, frequency and amount, it will not fail. It is when those parameters are violated that poor lubrication results in failure.
  • Contamination: Causes 14% of failures. To avoid this, choose a bearing with a seal from the environment, as it is necessary to keep the lubricant in and the contaminants out.
  • Fatigue: Causes 34% of failures. As shown in the graph below, fatigue most often occurs right after installation or at the end of the normal or rated service life. Our goal is to stop the fatigue failures that occur in “infancy” and to extend “end-of life fatigue” to the rated

I hope this tip was helpful, and if you have any more questions, don’t hesitate to leave a comment in the section below!