What precautions should be taken when lubricating precision machine tool bearings?

Release date:

2025-11-11

The selection of lubrication methods for machine tool bearings depends on factors such as bearing speed, load, allowable temperature rise, bearing type, and relevant operating conditions. Below, Youwei Bearing will explain the key considerations for grease lubrication of machine tool bearings. Grease lubrication is characterized by strong adhesion of the lubricant, ease of use, and simple maintenance—eliminating the need for frequent addition or replacement of the lubricant. However, it generates higher friction resistance compared to oil lubrication. The most commonly used grease for machine tool bearings is lithium-based grease with mineral oil as the base oil; for high-speed, precision bearings, composite barium-based grease formulated with synthetic diester lubricants can also be employed. When applying grease to rolling bearings, avoid overfilling, as excessive grease can generate heat due to churning, leading to melting, degradation, and ultimately loss of lubricating effectiveness. The appropriate amount of grease to fill the bearing should be determined based on the bearing’s type, size, and operating speed. For high-speed, precision machine tool bearings, it is recommended to fill only 15% to 25% of the internal free space within the bearing. Grease-lubricated bearings must undergo an initial running-in period at startup. During this phase, excess grease is forced into the bearing raceways, ensuring even distribution throughout the bearing and helping maintain thermal equilibrium during normal operation. Start the running-in process at a low speed (e.g., half of the rated speed), gradually increasing the speed once stable temperatures are reached—continuing until the bearing reaches its operational speed and the temperature stabilizes. Machine tool bearing lubrication: The choice of lubrication method and lubricant type is determined by comprehensively evaluating the machine tool’s design, level of automation, operating conditions, and precision requirements. Machine tool lubrication must not only minimize friction and energy consumption but also effectively prevent temperature rises and vibrations. As complex and highly precise machines, machine tools often incorporate diverse transmission systems, each demanding specific lubricant properties tailored to the equipment type, environmental conditions, and the desired precision levels—including viscosity, oiliness, antioxidant capacity, and extreme-pressure resistance.

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What precautions should be taken when lubricating precision machine tool bearings?