Bearing Lubrication Monitoring with Ultrasound

Why Lubricate Bearings?

Bearing lubrication

For 4000 years we have been lubricating our machinery and rotating assets to increase their efficiency, reliability and lifespan. Proper bearing lubrication minimizes the surface contact of machinery, reducing undesired friction, excessive heat, metal-on-metal contact and wear and tear.  

Lubrication not only protects ball and roller-element bearings from themselves by reducing friction but also from corrosion and the elements. Grease is the lubrication of choice within the industry, as it is easy to apply and it provides the bearing housing with a protective seal from the elements.

For a procedure proven reliable for the past 4 millennia, it is surprising to hear so many premature bearing failures are lubrication-related. In short, improper lube selection, amount, intervals as well as lubricant contamination and degradation are to blame. 

Bearing lubrication

Avoid these Three Common Mistakes when greasing bearings with Ultrasound

Why you need Ultrasound to Correctly Lubricate Bearings

Ultrasound is the best condition monitoring technology for detecting friction, impacting and turbulence. The main purpose of lubrication is to reduce undesired friction and metal-on-metal contact. Ultrasound can detect increased levels of friction as a result of too much, or too little grease. 

“With the SDT Ultrasound Solutions, you’re able to hear beyond the noise to detect the ultrasonic waves that your bearings emit. As you hear more, you have the ability to identify faults and lubricate or replace bearings before your asset fails.”

How to Determine when a Bearing Requires Grease

Taking measurements with your ultrasound device is the best, and easiest way to determine when your bearings require grease. Observing changes in dB’s is the first telltale sign that your bearing requires some maintenance  So, the first step is to establish a baseline.  

How to Grease Bearings Right, Never Under or Over Lubricate again

The only way to know when a bearing is in need of lubrication is monitoring its condition with an ultrasound device. Over time, bearing grease degrades and friction levels increase which is detectable with ultrasound. For this reason, and in order to prolong its life and prevent failure, the bearing needs grease replenishment.

An Ultrasound Device allows users to carefully monitor a bearing during a lubrication task. Both audio and visual representations of the bearings decibel level are displayed to provide greasing guidance. As grease is added to the bearing the decibel levels will decrease. Once dB levels begin to climb slightly, you know you have reached the optimal level of grease.  

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    Questions concerning Bearing Lubrication Monitoring

The best and simplest approach to assess when your bearings require grease replenishment is to first implement a time-based lubrication program, completed by ultrasound measurements, in order to adjust it accordingly. Observing downward fluctuations in dB levels when adding small amounts of grease is the first clue that your bearing requires maintenance.

The amount of grease required by equipment is influenced by a number of factors (bearing speed, load, environment, temperature, etc.) As a result, all of these aspects must be taken into account, not only a “timing” component based on empirical calculations. With its algorithm, LUBExpert does the job for you by telling you what type of lubricant and how much grease is needed.

The use of too much or too little grease causes the bearing to wear out or break prematurely. The first occurs due to increased temperature and friction, while the second occurs due to metal-to-metal contact, which causes the bearing to seize after a period of time.

The best Ultrasound Device for Monitoring Grease Replenishment


The LUBExpert is a complete ultrasound solution to manage your acoustic lubrication program.

Poor greasing practices are a leading cause of bearing failure. LUBExpert tells us when to grease…
and when to stop.


The LUBEChecker is an ultrasound solution designed to optimize bearing lubrication.

This intuitive device ensures bearings receive the right amount of grease at intervals dictated by condition, not run time. It is Focused, Simple and Affordable.

Ultrasound software

The Ultranalysis® Suite 3 is the most powerful ultrasonic measurement management software ever designed for maintenance professionals.