Lubrication practices within a plant have a direct effect on plant and equipment reliability. When a lubricant is working effectively in a machine – with no chemical degradation and with limited contamination within it, wear will be reduced and equipment reliability will be improved. The key to achieving a reduction in component wear and an increase in equipment reliability, is an effective and clean average lubrication film thickness – or in order words protecting and maintaining a good lubrication viscosity.
What is Lubrication Reliability?
Any investigations conducted today on why bearings fail, will reveal the alarming fact that over 60% of the damages are lubrication related. The bearing is the rotating core of the machine and if we can reduce the lube related failures we will directly improve the equipment reliability, not to mention reducing the bearing consumption.
Bearings and other rotating components need a good lube film thickness to separate the metal components and reduce wear; however, generating a good film thickness is a chemically complex mechanism, which is dependent on many factors.
However, when the lubrication works in a reliable way, equipment reliability will improve. Meaning a Lubrication Reliability strategy is all about ensuring effective machine lubrication occurs within the machine resulting in reduced wear and failures.
It is all about Lube Film!
SKF has stated that, “bearings can have an infinite life when particles larger than the lubricant film are removed.” Meaning the removal of abrasive particles prevents bearing wear.
In a bearing with a good average lubrication film thickness, the metal surfaces are separated and the average thickness of this separation or film is very small, in fact it is about one twentieth of the thickness of a strand of human hair. See figure 1
When there are hard contaminants in the oil and they are greater in size than average lube film, then 3 body abrasive wear starts to happen. This then leads to surface indentation and scratching, which is a process that can lead to bearing or component failure.
Understanding Oil Contamination
The number one problem with lubrication today is contamination and this can be particle contamination or chemical contamination or both.
The effects of particle contamination on bearing life is supported by a research project conducted by Doctor MacPhearson, which looked at the relationship between filter ratings and millions of bearing cycles to fatigue failure. See figure 2 The bottom line being the lower the contamination level the longer the bearing life.
Managing Particle Contamination
There are 5 steps we need to consider in managing our oil cleanliness and contamination levels. These are:
- Receipt and of new oil.
- Storage and conditioning of new oil.
- Dispensing of the oil to the machines.
- Stopping contaminants entering the machine.
- Removing contaminants generated in the machine from wear.
Managing Chemical Contamination.
As mentioned in the article earlier the oil can also be contaminated chemically, for example water entering the system or oxidation occurring within the process. These chemical contaminants will also affect the average lubrication film thickness and any well managed lubrication activity will use an Oil Analysis process to monitor the development of them.
ROI or Return on Investment.
A well structured lubrication strategy will require some investments.
Depending on how advanced a company is with their existing lubrication strategy and their size, these costs can be anywhere from $20,000.00 to $150,000.00. A lot of money, however it is an investment that will be paid back. The following are three examples of where the investment payback will come from.
- The eliminating of one failed electric motor, due to lack of lubrication.
- The doubling of life of a number of gearboxes due to cleaner oil.
- The reduction in bearing spend, by a conservative 30% annually.
- The doubling in life of all hydraulic systems and pumps.
Lubrication practices within a plant have a direct effect on plant and equipment reliability. When the lubrication is working effectively, wear will be reduced and equipment reliability will be improved. A Lubrication Reliability strategy focuses on all parameters that protect the average lubrication film thickness thereby reducing component wear and increasing equipment reliability. Please feel free to email Ian Knight for any additional information or queries you may have.