The Leading Causes of Bearing Failure and How to Prevent it
Most failures of workplace bearings can be prevented. Bearings can fail due to a large range of reasons. By understanding the reasons for these failures, managers can avoid the risks and improve the productivity of the workplace. In the case of bearings, insufficient or the wrong lubrication is a leading cause of workplace failure. The lubrication can be for a number of reasons, including incorrect temperature, speed, or load.
Lubrication can also become contaminated from moisture. This can result in moisture contamination in the air or from airborne particles. The contaminants can also create additional wear on the components of the bearings. The solution is simple but requires commitment. Make lubrication schedules based on actual operating conditions rather than a generic time clock. Also, ensure that you avoid over greasing because it may create excess internal pressure, heat, and seal damage. Choosing the right lubrication type, the right amount, and right service intervals should be engineered decisions, not guesswork.
Contamination
You will need to consider microscopic abrasives such as dust, dirt, and moisture. Metal filings, and even moisture, will act like sharpened pencils and make a score on your raceways and rolling elements. This will eventually cause failure to occur sooner than normal operating conditions.
Contamination may be the result of inadequate sealing, improper installation, and careless storage. Factors contributing to contamination may include unclean tools, exposed housing bores, and unprotected handling.
It is vital that your installation environment is clean and that your sealing systems operate effectively. Handling, storage, and assembly are the parts of the process, that are crucial to the bearing longevity.
Improper Installation
Bearings that are improperly installed can be expected to fail before their predicted service life is over. Damage can occur almost immediately, for example, if someone improperly attempts to ‘drive’ a bearing onto a shaft by hitting the outer ring. During installation, if the bearing is inserted at the wrong angle, or the outer race is too tight, the load can become uneven and therefore, the stress can be concentrated at some points while leaving others stress-free.
The skills and tools to do these things do exist after all. Heat induction, for example, can be used to install a bearing with much less mechanical stress.
Overloading and Wrongly Specified Application
If a bearing’s specified load rating, speed rating, and temperature rating are exceeded, the bearing will most likely fail. This is also true if the bearing specification is not adjusted after a change in the operating conditions, and even at the design stage.
Failing to strategically define the bearing’s application, either by specification or design, can ultimately lead to inadequate performance. This is all very true of a bearing designed for radial loads and then subjected to large, uncontrolled axial thrusts.
The choice of the bearing should become obvious after a thorough analysis of all operating conditions. The right bearing, specified and designed correctly, will minimise all forms of performance loss.
Failure, Fatigue, and End-of-Life Wear
After some time, all bearings will fatigue and fail, even if everything was done correctly with the installation. When a bearing rolls, stresses are developed below the surface and lead to surface damage of the bearing. This is called spalling, which is the breaking away of the material that is on the raceway.
When it comes to fatigue of the bearing, it is a fact of life that it will occur; however, there are ways to manage fatigue. Taking regular bearings and inspecting them, and measuring vibrations and temperatures all help identify the symptoms that occur before the eventual failure. While the L10 bearing life rating does give an estimate on bearing life, there are many real world factors that influence the life of the bearing.
Being Proactive
Being reactive to bearing failure is disruptive to the operation and very costly. Taking a proactive approach to maintaining bearings, like vibration and temperature monitoring, allow the team to close the loop and schedule replacements for when the operations are already planned to be inactive.
There are many patterns that regular maintenance people see before a bearing fails catastrophically. Understanding the failure along with root cause analysis will close the loop and help maintenance people to modify components instead of just replacing the broken pieces.
The four pillars of successful bearing management include: the right choice of bearings, correct bearing fitting, optimal bearing lubrication, and bearing condition monitoring. While the correct execution of each of these steps is not particularly difficult, it does require an understanding of the relevant technology, along with the disciplined application of the techniques.
With the correct strategies and processes, businesses can greatly improve the reliability and operational life of bearings, while also reducing expensive downtime.
