Over lubricating a bearing is about as hazardous as under lubricating it. When do you stop? Some people wait until grease flows out of it. That’s too much lubrication, to be sure.
Bearing manufacturers report that over lubrication is one of the major causes of bearing failure.
Because of over lubrication, the bearing can overheat from excessive loading. This will melt the lube and it will flow out of the bearing. The result: under lubrication and premature bearing wear and failure.
There are other ways that over lubricating a bearing can cause failure: the pressure of too much grease with no place to flow to is one of them. Electric motors have also been known to fail when too much grease creates a short circuit, resulting in total motor failure.
What causes over lubrication? Several factors predominate: improper training, lack of awareness and no written procedures for the process are some of the most prominent.
The proper tools are a definite help. One essential tool is a grease gun. Some of the newest models are calibrated for measured grease delivery and other feature digital gauges to track delivery.
Another new technology, one employed by IBT IMT (Industrial Maintenance Technologies), is acoustic or ultrasonic. This involves lubrication methods which are modernized and often can prevent over lubrication. Some MRO managers are using this proactive, condition-based lubrication method instead of their old time-based lubrication approaches.
The new acoustic and ultrasonic devices “listen” to the sounds of the bearings. When properly lubricated, a bearing emits a smooth rushing sound. The technician can hear the amplified audio signal using noise blocking headsets. Some of the more sophisticated units also have feature digital meters to measure sound level readings. Some devices also include data loggers for record keeping.
A bearing needing lubrication sounds different than a properly lubricated one. It emits a much rougher sound. As the technician adds grease, he can actually hear the sound level smoothing out as the grease comes into contract with the bearing.
Condition-based lubrication monitoring based on sound has two technical options to choose from:
- One is the sonic/audible sound approach. This method utilizes a device with a metal contact probe connected to a grease gun mounted amplifier and control unit. The operator wears noise-isolating headphones that cancel out background plant noise. This option is low cost, easy to use and the equipment is durable.
- Another option uses high frequency ultrasonic sensors. These have the advantage of having other applicable uses in your plant. They can be used to detect, amplify and then translate sound level into the audible spectrum. These systems also require noise attenuating headsets. This option is more complicated and technically sophisticated.
Ultrasonic devices include digital meters, data logging and software. They have multiple other uses such as leak detection, steam trap and valve testing.
If you are concerned about bearing lubrication and these technologies sound effective, IBT IMT can help.
If you are not sure you want to tackle the job in-house, we will use our acoustic equipment or ultrasound technologies to your bearing lube and maintenance programs on a contract basis.
We can also help with regular vibration analysis for main machinery, laser alignment, general troubleshooting, many various types of predictive maintenance (PM) and repair necessary based your equipment. We can help you detect problems using our technologies and experience.
If you want more information, I’d like to hear from you.
