Principles of Lubrication

Posted on June 25, 2019

To perform at optimal levels, bearings require sufficient lubrication. When properly applied, lubricants can reduce friction, which reduces the amount of wear and tear experienced by the bearing part. Additionally, some types of lubricants can provide recirculation which serves as a cooling method, while other types can help to disperse heat buildup to improve system performance.

All of these characteristics help prevent damage to the bearing, as well as prolong its overall service life.

The Importance of Proper Lubricant Selection

bearing lubricationChoosing the proper lubricant for different equipment can make a huge difference in the performance and life span of a piece of equipment or system. While the proper lubricant can ensure smooth and reliable performance, the wrong lubricant can result in frequent maintenance and service outages.

Precision Bearing Lubrication

Anti-friction bearings need adequate lubrication in order to sufficiently counter friction. Lubrication for these types of bearings is even more important as the systems which employ them typically need to meet higher reliability, accuracy, and performance standards.

Regardless of the application, choosing the proper lubricant can benefit bearing performance in several ways, including:

  • Reducing friction: Lubricants can specifically prevent metal-on-metal contact between the bearings and raceways or exterior casing. The right lubricant can maintain a thin hydrodynamic film that remains constant despite the machinery's speed or heat buildup.
  • Preventing contamination: Many specialty lubricants can both keep contaminants out of sensitive internal components and reduce the risk of oxidation or corrosion.
  • Transferring heat: Some lubricants can absorb heat energy and conduct it away from the bearing to maintain safe operational temperatures.

Lubricants come in three basic forms for industrial application. These include:

  • Oils and fluid lubricants
  • Semi-solid or solid grease products (which are similar to fluid lubricants but also include a thickening agent)
  • Dry lubricant powders and films for precise placement

Lubricant Selection

The machinery system and its operating conditions dictate which form and makeup of lubricant are the most suitable for use. Because lubricants need to be able to withstand heat and reduce friction, the most important factors to consider when selecting a lubricant are:

  • Operating speeds
  • Minimum and maximum system temperatures (both at startup and during continuous performance)
  • The viscosity of the lubricant in that range of operating temperatures

Incompatibility of Greases: Specialty Greases for Unique Applications

There are several different types of specialty greases that have been designed to provide ideal levels of lubrication and resistance to heat damage. However, mixing two or more greases, with different base oils together, may result in a final lubricant product that loses many of the individual products' unique benefits. When the final lubricant is markedly less stable or less resistant to heat damage and fiction buildup, the original greases are considered incompatible.

As a general rule, different greases should not be combined unless the product directions explicitly allow for such mixtures. Instead, companies should look for specialty greases and lubricants specifically designed for the conditions of their machinery and systems. 

It is always critical to match the service life of the grease to the service life of the bearing.

Using the correct grease offers several advantages, including:

  • Cost-effective application and maintenance: Grease lubricants are affordable solutions. Using the right lubricant also saves companies money by increasing bearing longevity and through savings on wear, maintenance, and parts replacement. It also does not require special application equipment.
  • Long product life: It can last a long time in operational machinery without degrading.
  • Low levels of friction buildup: It can help reduce frictional buildup during equipment startup and continued activity.
  • Suitability in a wide variety of circumstances: Grease can be used for lubrication in machinery across every industry. It reduces friction in low speed and high-speed bearings and can safely be used in equipment with dynamic speed levels.

To Learn More, Download Our Bearing Maintenance Guide

3D-Cover-Emerson-bearing_Maintenance_GuideChoosing the proper bearing lubricant can help keep your facility's machinery safe and operational. However, before selecting one, it is important to understand your machinery's unique specifications and lubrication requirements.

For more information on how to keep your system's bearings in optimal condition and increase their operational lifespan, download our Bearing Maintenance Guide.



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