Most equipment lubrication related failures are the result of contamination or improper lubrication practices. Equipment, if operated within design specification, will generally fail because of lubrication related issues before engineered service life is reached.
Contamination can be the result of environmental conditions, product mixing, lubricant degradation products, water, dirt and debris, and system generated contaminants. Environmental conditions can stress a lubrication system as well as contribute to the other factors mentioned above. Lubrication degradation affects the lubricating quality of product overtime. Degradation materials will tie up useful additives, impede flow, affect proper lubricant surface film, and cause corrosion. Water is a major contributor to shortening the service life of bearings, pumps, valves, and any close tolerance design. Dirt and debris greatly accelerates abrasive wear. Improper circulating system design can create hot spots, impede proper filtration, and impede proper fluid flow. Inadequate reservoir design will allow contaminants to re-enter circulating systems and not allow heat to dissipate.
Improper lubrication is caused by under or over lubricating, incorrect lubricant in service, inadequate lubrication frequency and overextended drain intervals. Under lubrication will starve pumps and circulating systems, thus create surface fatigue or surface wear due to an inadequate surface film. Over lubrication can create foaming and cause seals to fail. Greased bearings are particularly susceptible to over lubrication. Topping off with an incompatible lubricant can effectively impede additive function, create insoluble deposits or reduce lubricating properties. Using a lubricant that is improper for the application will greatly reduce equipment service life. Inadequate lubrication, insufficient re-lubrication frequencies, or overextended drain intervals will allow contaminants to buildup and prevent consistent proper lubrication properties.
Attention to proper lubrication and maintenance of the lubrication system will promote optimal equipment service life. Monitoring your lubricant in service will provide a valuable tool for maintaining your lubricating system as well as equipment health. At least half of all equipment failure can be traced to lubrication as a root cause.
David Doyle, CLS, OMA I, OMA II