SDT Reminds: Avoid These Three Mistakes When Lubricating Bearings
Lubrication of rolling element bearings is one of the most misunderstood tasks in industry. 40 percent of bearings never live to their engineered life cycle and bad lubrication practices are the leading cause. Bearings need grease to reduce friction levels.
By avoiding three common mistakes when greasing bearings you can predict the right time to grease, how much grease to apply, and be confident of the bearing’s overall health.
Mistake 1 - Lubricating based on TIME instead of CONDITION
Bearings need grease for one reason only; to reduce friction. As long as the lubricant is performing that service well, there should be no need to change it. Yet we frequently do, with catastrophic results.
Re-lubricating a bearing just because your calendar told you “time is up!” is the first mistake. Monitor, measure, and trend friction levels with ultrasound to know when it is the right time to grease.
Mistake 2 – Over and Under Lubrication
The second mistake is adding the wrong quantity of grease. Too much grease builds pressure. The bearing now has to work much harder to push the rolling elements through a mud bog of grease.
The temperature rises inside the bearing decreasing the lifespan of the lubricant. Not adding enough grease has the same life-shortening effect.
Instead, monitor bearing friction with ultrasound as new grease is applied. Measure the drop in friction as the grease flows in to the bearing cavity. Once bearing ultrasound values stabilize, stop! The job is done.
Mistake 3 – Using a “Listen-Only” Ultrasound Instrument
There is good technology and then there is… Well, let’s just say listening to a bearing with an ultrasound device that gives no measurement feedback is a recipe for disaster. The audible feedback is too subjective to make comparative conclusions.
The third mistake is depending solely on subjective ultrasound noise. Always use an instrument with digital decibel metering. Better still, use a device that provides multiple condition indicators. Condition Indicators help differentiate between bearings that need grease and bearings that need to be replaced.
Clear Benefits of Avoiding the Three Mistakes
Ultrasound assisted lubrication of rotating assets offers significant benefits. The best way to determine the lubrication requirement of a machine is to monitor friction levels; not time in service. This is just one of the many versatile applications for ultrasonic asset condition management.
Download the SDT Lubrication Handbook
