By Chris Wilson
There are two main types of bearing lubricants: oil and grease. While grease lubricants are made by mixing oil lubricants with thickeners, this process gives grease lubricants certain benefits that may make them more suitable for use.
One of the main reasons for using grease is its viscosity. Oils are more likely to drain or leak out of a bearing, while greases are solid enough that they will stay where they are applied. This makes is a superior option for applications that will be shut down occasionally, as the grease will remain in the part and prevent the potential for dry starts when the application is turned on again. The lack of leakage is also critical for any applications in environments where products can’t be contaminated, such as food processing spaces. In addition, there are greases available that are specifically made for environments with food. Tightly-packed greases can also help block contaminants from entering a bearing, which is useful in environments with dirt or water. These contaminants can then be cleaned out during regreasing.
Another consideration for using grease involves the operating temperatures and speeds of a specific application. A higher viscosity means more rolling resistance and heat build-up, which means that oil lubricants are typically more suitable for high-speed, high-temperature applications. However, applications with medium or low heat and speed requirements are generally very suitable for grease.