Why Lubrication Matters

During operation, rolling elements inside the linear guideway run along the raceway and generate friction. If lubrication is insufficient, the frictional resistance in the rolling area increases, metal-to-metal contact becomes more frequent, and the rolling parts wear out more quickly. As a result, the overall service life of the linear motion system is shortened.

To prevent this, the linear guideway must be lubricated with a suitable lubricant in the right amount and at the right interval.

Types of Lubricant and Lubrication Methods

Linear motion systems commonly use two types of lubricants:

• Grease – suitable for general applications, easy to maintain, longer re-lubrication intervals.
• Oil – suitable for higher speeds, continuous operation, or centralized lubrication systems.

Correspondingly, lubrication methods are generally divided into:

• manual lubrication (replenished at set intervals)
• forced or automatic oiling (continuous, controlled feed rate)

The final selection should be based on the operating speed, duty cycle, mounting direction, and environmental requirements of the application.

Grease Lubrication

For most standard operating conditions, grease lubrication is sufficient and easy to service on site.

Standard Interval

Under normal operating conditions, the grease should be replenished every 100 km of travel. The actual interval may vary depending on load, speed, ambient temperature, and contamination.

Recommended Grease

The standard pre-filled grease is lithium-based grease No. 2, which provides stable lubrication performance for typical linear guideway applications.

How to Distribute Grease Evenly

After greasing the carriage, move the carriage back and forth with a minimum stroke length equal to three carriage lengths. Repeat this procedure at least twice to make sure the grease is evenly distributed inside the carriage and reaches the raceway area.

Oil Lubrication

Oil lubrication is suitable for applications requiring continuous lubrication, higher speeds, or where a centralized lubrication system is already installed.

Recommended Oil Viscosity

Use lubricating oil with a viscosity of 30–150 cSt. This range provides good film formation for most linear guideway raceways.

Feeding Rate

Oil should be supplied at a proper hourly feed rate according to the operating conditions. Too little oil will not cover the raceway sufficiently; too much oil may cause leakage and contamination.

Mounting Direction Matters

When the guideway is installed in a non-horizontal direction (vertical, wall-mounted, or inverted), gravity may prevent the oil from reaching the raceway area. In such cases, specify the installation direction during design or ordering so that the lubrication points can be arranged correctly.

Short-Stroke and Special Cases

Short-stroke applications are easily overlooked but need more attention, because the carriage does not travel far enough to allow the lubricant to spread over the entire raceway.

• When the operating stroke length is less than the total length of two carriages, install lubrication fittings on both ends of the carriage to ensure adequate lubrication.
• When the stroke length is less than half the length of one carriage, move the carriage back and forth up to the length of two carriages while lubricating. This ensures that fresh lubricant actually reaches all rolling contact areas.

Best Practices for Longer Service Life

• Use only clean, recommended lubricants.
• Follow the re-lubrication interval or shorten it in dusty or high-load environments.
• After lubrication, operate the carriage several times to distribute the lubricant.
• Check for leakage or contamination around lubrication ports.
• Record lubrication dates as part of preventive maintenance.

FAQ: Linear Guideway Lubrication

1. Can I mix different greases?

It is not recommended to mix different types or brands of grease, as their base oils or thickeners may not be compatible, which can reduce lubrication performance.

2. How do I know the interval is correct?

If the operating environment is dusty, humid, exposed to coolant, or running at high speed, shorten the lubrication interval accordingly.

3. What happens if I do not lubricate?

Friction increases, the rolling elements wear faster, running resistance becomes unstable, and the linear guideway service life decreases.