precision positioning slide table Daily Maintenance List: Grease selection and Filling cycle

Date: Jan 14 2026

The lifespan and precision stability of precision positioning slide tables (such as components like linear guides, ball screws, crossed rollers, etc.) depend 80% on the maintenance of the lubrication system. As the core medium for reducing friction, heat dissipation and rust prevention, the incorrect selection or outdated application of grease can lead to accelerated wear of the guide rails, positioning drift, increased noise and even jamming faults. This article provides a maintenance plan that can be directly implemented from three aspects: the logic of grease selection, the determination of the filling cycle, and the standardized operation process.

I. Grease Selection: The core is "matching the working conditions"

The performance of the grease must be strictly matched with the movement parameters of the slide table (speed, load), environmental conditions (temperature, dust), and component materials (metal/ceramic) to avoid "over-lubrication" or "under-lubrication".

1. Key parameters: Understand the grease grade

Grease grades typically include base oil viscosity, thickener type, and NLGI consistency grade. The following indicators need to be given special attention:

The influence of parameter meanings on the slide table

The viscosity of base oil is commonly classified by ISO VG grades (such as VG32, VG68), indicating the kinematic viscosity (mm²/s) at 40℃. If the viscosity is too low, the oil film is prone to rupture (wear). Too high → Increased resistance (heat generation, high energy consumption).

The NLGI consistency grades range from 0# (soft) to 6# (hard), with the higher the number, the thicker it is. For precision slides, 1# to 3# are commonly used. For precision guides, 2# to 3# are selected (taking into account both fluidity and adhesion). For heavy loads and low speeds, choose 3# to 4# (resistant to compression).

Thickener types: lithium-based (general-purpose), composite lithium-based (high-temperature), polyurea (long-life), bentonite (wide temperature range). Lithium-based grease offers high cost performance (applicable to -20 to 120℃). For high-temperature environments (> 150℃), choose composite lithium-based or polyurea. For cleanrooms, choose ashless type.

Additives: Extreme pressure agent (EP, anti-heavy load), rust inhibitor (anti-corrosion), antioxidant (extended service life), solid lubricant (MoS₂, emergency lubrication). Ep-containing agents are essential for heavy loads/shock loads. For damp environments, choose products containing rust inhibitors. For high-speed movement, choose low-friction additives (such as PTFE).

2. Match the grease according to the type of guide rail

The friction pair characteristics of different guide rail structures vary greatly, and targeted selection is required

Guide rail type, friction pair characteristics, recommended grease type, prohibited type

Ball guide rail point contact, high-speed low-load low-viscosity synthetic oil-based lithium-based grease (ISO VG32~46, NLGI 1#~2#), high-viscosity grease containing EP agents and antioxidants (such as THK AFG) (> VG68), solid particle grease

Cross roller guide rail line contact, medium and high load, anti-overturning moment medium viscosity compound lithium-based grease (ISO VG68~100, NLGI 2#~3#), low viscosity grease containing extreme pressure agent (such as IKO LWA) (< VG32), easily disintegrating grease

Sliding guide rail surface contact, low-speed heavy-load, easy-to-crawl high-viscosity lithium-based grease (ISO VG100~220, NLGI 3#~4#), low-viscosity grease containing MoS₂ solid lubricants (such as NSK LG2), calcium-based grease with moisture

Ball screw screw pairs, high speed, anti-crawling low-viscosity synthetic oil-based grease (ISO VG32-46, NLGI 1#), high-viscosity grease containing anti-friction agents (such as HIWIN GV3) (prone to accumulate between the screw threads)

3. Adjust according to environmental conditions

• Temperature:

• Room temperature (-20 to 80℃) : General-purpose lithium-based greases (such as Shell Gadus S2 V220 2);

• High temperature (80-200℃) : Complex lithium-based greases (such as Mobil Polyrex EM) or polyurea greases (such as Kluber Summit LCG 111);

• Low temperature (-40 to -20 ° C) : Low-viscosity synthetic oil-based lipids (such as ISO VG15 to 22, NLGI 0#, such as Dow Corning Molykote G-0100).

• Dust/Moisture: Select sealing grease (containing rust inhibitors and anti-emulsifiers), or install a protective cover (such as a bellows cover) on the slide table to prevent dust from mixing in and damaging the oil film.

• Cleanroom (Class 1000 or below) : Select dust-free grade grease (such as NYOGEL 774A, particle size ≤10μm), and avoid silicone oil types (volatile and prone to air pollution).

4. Brand compatibility principle

• Do not mix different brands/types of greases: Base oils and thickeners may undergo chemical reactions (for example, the mixture of lithium-based and calcium-based greases will solidify), leading to lubrication failure.

When changing brands, thorough cleaning is required: first, remove the old grease with kerosene or a special cleaning agent, then dry it and add new grease (the proportion of residual old grease should be less than 5%).

Ii. Filling Cycle: Dynamic calibration to avoid a one-size-fits-all approach

The filling cycle should be determined comprehensively in combination with the usage intensity, load, speed and ambient temperature. The core is to "monitor the lubrication status" rather than a fixed time.

1. General reference period (under no monitoring conditions

Application scenarios: Load speed, ambient temperature, filling cycle

Intermittent operation (less than 4 hours per day), light load (≤ 50% of rated), low speed (≤0.5m/s), normal temperature (20~30℃), once every 6 months

Continuous operation (8 to 16 hours per day), medium load (50% to 80%), medium speed (0.5 to 1m/s), normal temperature, once every 3 months

High-frequency operation (more than 16 hours per day), heavy load (more than 80%), high speed (more than 1m/s), high temperature (more than 40℃), once a month

2. Dynamic adjustment: Judged by "abnormal signals"

When the following phenomena occur, immediate fat replenishment or shortening of the cycle is required:

• Increased noise: The guide rail makes a "rustling" abnormal sound (oil film rupture, direct metal contact);

• Increased running resistance: There is obvious jamming when manually pushing the slide table (the grease has hardened or is insufficient);

• Temperature rise: The surface temperature of the slide table is more than 10℃ higher than usual (frictional heat generation intensifies);

• Grease discoloration: Normal grease is light yellow. If it turns black, gray (containing metal shavings) or has an unpleasant smell (oxidation and deterioration), it must be completely replaced.

3. Initial filling and replacement cycle

• First addition: After the new slide table is installed, it is necessary to add the initial grease as required by the manufacturer (usually 60% to 80% of the internal space of the slide block, to avoid excessive amount causing heating during stirring).

• Complete replacement cycle: Even if it is not exhausted, it needs to be completely replaced every 12 to 24 months (old grease loses its lubricity after oxidation), especially in high-temperature and high-humidity environments, the replacement cycle should be shortened to 12 months.

Iii. Standardized filling operation procedures

Step 1: Preparations

• Tools: Special grease gun (paired with a needle of the appropriate diameter, such as a 1-2mm fine needle for the slider oiling hole), lint-free cloth, brush, torque wrench (check the tightness of the oiling hole screw).

• Environment: Shut down the machine and cut off the power. Clean the dust on the surface of the slide table (use compressed air to blow away any debris in the gaps).

Step 2: Clean the old grease (for the first time or when replacing)

Unscrew the grease drain hole screw on the side of the slider (if any), and use a brush to remove the old grease.

Inject a small amount of cleaning agent (such as kerosene), and repeatedly move the slide table (manually or at low speed) to discharge the waste grease.

Dry the remaining cleaning agent with a lint-free cloth to ensure there is no liquid residue (to avoid diluting the new grease).

Step 3: Add new fat

• OIL filling position: The oil filling hole of the ball guide rail slider (usually on the side of the slider, marked with "OIL" or the oil can icon); The oiling port of the ball screw nut.

• Filling volume:

• Slider: Add 0.5 to 2g (about the size of a soybean) at a time. It is advisable for a small amount of new grease to overflow from the inside of the slider (too much will be squeezed out and wasted, while too little will result in insufficient lubrication).

• Lead screw nut: Apply a thin layer evenly along the thread (thickness ≤0.1mm) to avoid accumulation at the end.

• Key points of operation: Press the liposuction gun slowly to prevent air bubbles from entering. After filling, tighten the oil filling hole screw (the torque should be as per the manufacturer's requirements, such as 2 to 3N·m for M4 screws).

Step 4: Run the verification

Start the machine and run it unloaded for 5 to 10 minutes to observe if there are any abnormal noises or lag.

• Use an infrared thermometer to measure the temperature of the slide table (the normal operating temperature should be ≤ ambient temperature +15℃).

Record the date of this addition, the type of grease, and the amount used (establish a maintenance ledger).

Iv. Precautions: Avoid 5 Major Maintenance Misconceptions

The misconception of "the more, the better" : Excessive grease can lead to increased stirring resistance, heat generation, and even be squeezed into the guide rail raceway to contaminate the steel balls (especially in high-speed scenarios).

2. The misconception of "never replace for life" : Grease will gradually lose its effectiveness due to oxidation and water absorption. Even if it is not used up, it needs to be replaced regularly (refer to the "complete replacement cycle").

3. Misconception of "General grease substitution" : Replacing precision guide rail grease with ordinary grease (calcium-based grease) will lead to rapid failure due to its low dropping point (< 90℃) and poor water resistance.

4. "Neglecting sealing" misconception: Loose screws of the oil filling holes or the absence of sealing rings can lead to grease leakage and dust intrusion (the integrity of the sealing parts should be checked each time maintenance is carried out).

5. "No record" misconception: Without establishing a maintenance ledger, it is impossible to trace the cause of lubrication failure (such as whether a certain batch of grease has quality issues).

V. Recommended Greases by Mainstream Manufacturers (For reference)

Recommended lubricating grease characteristics for manufacturer guide rail models

THK HSR series ball guide AFG Grease (ISO VG32, NLGI 2#) Low noise, long service life (10,000km)

HIWIN EGR series cross roller guide GV3 Grease (ISO VG68, NLGI 2#) has high wear resistance and anti-overturning moment

IKO LRX series linear guide rails LWA Grease (composite lithium-based, ISO VG100) high-temperature resistant (150℃), containing EP agent

The NSK LH series sliding guide LG2 Grease (including MoS₂, ISO VG220, NLGI 3#) is suitable for anti-crawling, heavy-load and low-speed use

Summary

The core of grease maintenance for precision positioning slide table is "on-demand matching, dynamic adjustment, and standardized operation" : Select the corresponding grease based on the type of guide rail, load speed and environmental conditions. Dynamically calibrate the filling cycle through abnormal signals. Strictly follow the "cleaning - filling - verification" process and establish a maintenance ledger for traceability. Remember: Regular lubrication is not "extra work", but the "minimum cost investment" to extend the service life of the slide table and ensure accuracy.