In general terms, a failure can be defined as the failure to meet a certain objective or expectation.
Therefore, in order to define a “lubrication failure” it is important to list the objectives that have not been achieved in terms of lubrication.
The objectives are very often attributed to lubricants, however, they are supported by the lubrication method, system and practices.Among others, the objectives include:
- The lubricant has a strong film that allows the separation of the moving parts to minimize friction, wear and excessive heat generation.
- The lubricant must act as a heat transfer fluid to cool the machine and its components, as well as transfer force, performing work in hydraulic and hydrostatic applications.
- Allow the removal of contaminants from the lubricant or lubrication system through the separation method.
- The lubricant should prevent the creation of varnish and sludge in the system, remaining in place even after some cleaning of the lubricated components and also simplifying and extending the lubrication and inspection activities, protecting against rust and corrosion.
However, the achievement of the aforementioned objectives, consequently, will contribute to the increase of the machine’s useful life and the realization of a reliable operation.
Thus, when one of the described objectives is not achieved, we can say that we are facing a failure in lubrication.
Note that the unfulfilled objective may represent a number of possible failures that may be the result of a single cause or a variety of causes combined.
These causes can be generated by (i) properties of the lubricant and its performance, (ii) lubrication system, (iii) lubricant handling and application practices, (iv) the operation of the machine or (v) the presence of contaminants in the work environment.
It must always be borne in mind that a failure in lubrication can trigger a failure in the machine.
As a rule, failures seen in lubrication-related machines are easy to identify when there is a catastrophic problem.
However, in other cases, the connection to a lubrication failure may not be very evident, which (i) when combined with other mechanical or operational issues, (ii) when the lubrication failure affects the machine’s performance or efficiency, but produces a catastrophic event or even (iii) when maintenance practices mask existing lubrication problems (e.g., change bearings more frequently to avoid accentuated failures).
We can thus conclude that it is possible to define a lubrication failure as a malfunction that occurs when we are trying to achieve the lubrication objectives.
In practical terms, a failure related to lubrication can be defined that compromises the machine’s reliability or its useful life.
Finally, it should be remembered that this type of failure cannot always be related to its causes due to excessive programmed practices, incorrect classification of failures or due to the lack of sufficient information to analyze the problem.