Common Reasons Why Oil / Grease Lubricated Bearings and Plastic Bearings Fail

Bearings are essential machinery components. Bearings protect the moving shaft from wear and damage, keeping it in place with little friction. They need to be lubricated in order to do so. Oil/grease lubricated bearings and self-lubricating plastic bearings are common but often times not capable of handling extreme situations. Below are the main reasons they might fail.

Are you experiencing oil/grease lubricated bearing or plastic bearing problems/failures? If so, chat with us now or email us at sales@graphalloy.com

Reason #1: High Temperatures
Bearings for high temperature ovensAt high temperatures, oil/grease tends to carbonize and plastics will melt or deform. There is also the chance of fire with grease/oil lubricants at high temperatures. Plastic bearings can also expand, rapidly seizing the shaft or neccesitating large clearances. If you use oil/grease lubricants or plastics in this situation, you could face failures due to part wear, shaft seizure, and other serious issues.

Reason #2: Low Temperatures
cold bearing applicationAt extreme low temperatures, such as cryogenic applications, oil/grease lubricants can solidify and plastics can become brittle. Failures can also result from plastics shrinking.

Reason #3: Vibration
failed plastic bearingWith high vibration loads, the lubricants can be expelled or simply migrate away from the bearings. If a bearing needs a large clearance due to thermal expansion (as is often the case in oil/greased lubricated metal bearings and plastic bearings), this problem is worsened. Sometimes vibration can even break the bushing.

Reason #4: Corrosives and Washout
tough corrosive bearing applicationAcids, alkalies, and hydrocarbons can present problems for lubrication and plastics. Oil/grease lubrication and plastics can dissolve in these corrosives. Oil/grease lubrication can be washed away, necessitating expensive maintenance to continuously re-grease bearings.

Reason #5: Dust, Ash, and other particulates
dust bearing machineDust and ash, among other particulates (common in mills or coal plants, for example), can combine with grease and oil to cause a lapping compound that can damage part surfaces/ wear away rotating parts.

Reason #6: Dry Run and low viscosity pumpage
plastic bearing failure pictureIn pump settings, pumpage around a bearing allows natural lubrication and a barrier, but when pumpage is not present during startup (a dry run) damage will ensue if the bearings are unlubricated. Metal damage known as galling is frequent and can seize a pump. Plastics, such as PEEK, may enable a pump to run dry briefly, but heat builds up. A catastrophic crash necessitating a rebuild of the pump will be required, including replacement of the thermoplastic parts.

Reason #7: Heavy Loads
Greasy bearingHeavy loads can squeeze out traditional lubrication, leading to galling and seizure. Plastics can deform under heavy loads.

Reason #8: Infrequent Operation / Inactivity
infrequently used machineWith too much idle time, lubricants can be pushed out of the contact area or solidify, which means friction and galling at start up.

Is there another solution?
A self-lubricating bearing made from the Graphalloy graphite/metal alloy can potentially solve all of these problems. It can withstand higher temperatures than grease or plastics. It can withstand lower temperatures. It allows tight clearances to reduce vibration. It will not wash out and is compatible with many corrosives. It will not combine with dust or other particles to create a galling compound. It can operate during dry runs. Its lubrication will not be pressed out by heavy loads. And finally, it works just as well after periods of inactivity.

Are you looking for a wide temperature range, tight clearance, run dry, self-lubricating bearing? If so, chat with us now or email us at sales@graphalloy.com

pump bearings

9/13/2019