Machine tool guide rail lubrication and characteristics

Selecting appropriate lubricants, lubrication methods, and lubrication intervals is critical for machine tool guide lubrication. The following key points should be noted:

Selection of Lubricants: Oil or Grease Based on Machine Tool Characteristics

1.High-speed machines and hard rail machines are recommended to use oil lubrication.
2.For vertical machining centers (VMCs), drilling-tapping machines, and other hard railmachines, lSO VG 68# lubricating oil is advised.
3.For horizontal machining centers with linear guides and gantry machining centers (largemachines), lSO VG 220# lubricating oil is recommended.
4.Increasingly, customers are adopting grease lubrication instead of oil lubrication forthree-line rail machines.
5.Grease recommendation: Use semi-fluid grease with extreme pressure (EP) additivesand rust inhibitors,specifically NLGI 00 Or NLGI 000.

2.Dispenser displacement selection and lubrication frequency are critical to machine tool lubrication. All dispensers must meet the minimum displacement requirements specified by the linear guide manufacturer (see the minimum recommended values for THK sliders in the table below). The lubrication interval for oil is relatively fixed: it is recommended to be 10 minutes (not exceeding 15 minutes) for ISOVG68# oil, and 2 minutes for ISOVG220# oil. For grease lubrication, the interval ranges from 1.5 to 8 hours depending on equipment operating conditions and protection.

BAOTN offers both specialized grease pouches and barrel grease for machine tools.

‌3. Different lubricating oils have varying chemical compositions; mixing incompatible oil types may induce chemical reactions, potentially leading to guide rail corrosion.‌
‌4. Guide rail sliders must be pre-lubricated before machine assembly and shipment, and the pre-lubrication process requires full travel stroke coverage.

Spindle Lubrication in Machine Tools & Characteristics

Oil-Air Lubrication Principle
The lubrication system intermittently dispenses a timed and measured amount of oil, which is carried by compressed air through the pipeline. The oil gradually forms a continuous film along the pipe wall and develops into a stable flow at the outlet, providing precise lubrication to precision bearings.

Oil-Air Lubrication Function

Precise, minimal oil supply reduces bearing heat generation, effectively controlling spindle temperature rise and ensuring operational accuracy. The positive pressure created by compressed air in the bearing housing prevents dust and moisture from entering, thereby extending bearing service life.

Key Points of Oil-Air Lubrication
1.Oil Selection: Use spindle-specific lubricants with an ISO VG of 32 to 68 for high-speed motorized spindles.
2.Oil Filtration: A 3–5 μm filter must be installed, and the filter element should be replaced annually to prevent clogging and excessive pressure drop.
3.Compressed Air Quality: The pressure dew point must be below –20°C to prevent free moisture and avoid bearing rust. Use oil-free compressors to ensure oil-free air; install an air dryer if necessary.
4.Start/Stop Procedure: Pre-lubricate the spindle before startup (approx. 15 minutes over 10 cycles). Run the system briefly after shutdown to flush out debris.
Mist Lubrication Principle
1.Compressed air and lubricating oil (typically ISO VG 32 or similar viscosity) are mixed in a mist generator. The air stream atomizes the oil into fine droplets (1–3 μm in diameter) to form an oil mist. The mist is delivered through distribution lines to lubrication points, where a condensate nozzle converts it into larger oil droplets for bearing lubrication.
Key Points of Mist Lubrication
1.Oil Selection: Use spindle-specific mist lubricants or turbine oils with an ISO VG of 10 to 46 for high-speed motorized spindles.
2.Oil Filtration: A 3–5 μm filter must be installed, with annual replacement of the filter element to avoid clogging and excessive pressure drop.
3.Compressed Air Quality: The pressure dew point must be below –20°C to prevent free moisture and bearing corrosion. Use oil-free compressors; install an air dryer if needed.
4.Start/Stop Procedure: Pre-lubricate the spindle for 1 minute before startup. Run the system briefly after shutdown to flush out debris.

MQL (Minimum Quantity Lubrication) in Machine Tools & Characteristics

MQL is a near-dry machining method, categorized into external and internal systems
1.External MQL: A micro-dosing pump delivers an extremely precise amount of lubricant to the nozzle, where compressed air disperses the oil into droplets—achieving lubrication with minimal atomization—directed at the cutting tool.
2.Internal MQL: An oil mist generator atomizes the oil, which then passes through the spindle and tool to reach the machining contact zone, providing precise lubrication.
Benefits of MQL
MQL reduces cutting fluid consumption, lowers handling and disposal costs, extends tool life, increases cutting speed and machining efficiency, and improves surface finish quality.

Machine tool guide rail lubrication and characteristics

Selecting appropriate lubricants, lubrication methods, and lubrication intervals is critical for machine tool guide lubrication. The following key points should be noted:

Spindle Lubrication in Machine Tools & Characteristics

MQL (Minimum Quantity Lubrication) in Machine Tools & Characteristics

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