Relubrication

Relubrication is the process of replenishing lubricant in machinery after it has degraded, leaked, escaped, or become contaminated. Its purpose is to restore a protective lubricant film, reduce friction and wear, prevent overheating, and maintain reliable performance and uptime.

Relubrication can be performed manually, using tools such as grease guns or oil cans, or automatically through centralized lubrication systems that dispense lubricant at set points and intervals. Intervals for relubrication may be time-based, usage-based, or condition-based, with triggers including elapsed hours, bearing temperature, vibration, or oil cleanliness. Condition monitoring, such as oil analysis or vibration checks, can help optimize the timing of relubrication.

Lubricant selection depends on the application, including bearing type, operating temperature, speed, load, and environment. Greases are common for many bearings and slow-moving components; oils are favored for high-speed or dynamic loads; dry lubricants may be used in high temperatures or vacuum. Selection also requires compatibility with seals, materials, and environmental constraints, along with appropriate viscosity and, for greases, NLGI grade.

Best practices for relubrication include cleaning the lubrication point, using the correct lubricant type and amount, and avoiding contamination during application. Over-lubrication can cause heat buildup and seal damage, while under-lubrication leads to accelerated wear and failure. Documentation of lubricant type, amount, and intervals supports maintenance planning. Safety and environmental considerations include proper handling, spill prevention, and proper disposal or recycling of used lubricants.