What Is Oil Mist Lubrication?
Oil mist lubrication is a method of delivering a very fine aerosol of oil particles to bearings, cutting tools, and other friction points using compressed air as the carrier. It delivers the minimum quantity of lubricant precisely where it is needed — making it ideal for high-speed, precision applications where conventional oil flooding or grease would cause churning, heat, or drag.
How Oil Mist Lubrication Works
- Air supply — Clean, dry compressed air enters the mist lubrication unit at a regulated pressure (typically 2–6 bar).
- Atomisation — The air passes through a venturi or nozzle where it draws oil from a small reservoir and atomises it into tiny droplets (1–3 microns in diameter).
- Transport — The oil-air mist travels through small-bore tubing to the lubrication points.
- Delivery — At each point, a reclassifier fitting converts the mist into larger oil droplets that coat the bearing surfaces.
- Drainage — Excess oil drains away from the bearing housing.
Types of Oil Mist Systems
- Pure Oil Mist (Dry Sump) — Only mist is delivered; no liquid oil pool exists in the housing. Used for very high-speed bearings where oil pooling would cause churning.
- Purge Mist (Wet Sump) — A small oil pool is maintained in the housing, with mist used to supplement and purge the housing with positive pressure to exclude contaminants.
Where Is Oil Mist Lubrication Used?
- CNC machine tool spindles — High-speed spindle bearings (10,000–80,000 RPM) benefit enormously from mist lubrication.
- Grinding machines — Wheel spindle bearings.
- Cutting tools — Mist provides cooling and lubrication at the cutting edge without flooding.
- Electric motors — Bearing lubrication in motors operating in clean environments.
- Pumps and compressors — Shaft bearing lubrication.
- Textile machinery — High-speed spindles in spinning and weaving machines.
Advantages of Oil Mist Lubrication
- Minimal oil consumption — very small quantities delivered precisely.
- No oil churning at high speeds — lower operating temperatures.
- Positive air pressure in housing excludes dust, coolant, and swarf.
- Suitable for simultaneous lubrication of many points from one unit.
- Lower friction and power consumption compared to oil bath lubrication.
- Extended bearing life.
Limitations
- Requires clean, dry compressed air supply.
- Oil mist must be collected — open discharge not recommended for enclosed environments.
- Not suitable for heavily loaded, slow-speed bearings.
SP Engineers manufactures oil mist lubrication systems and mist lubrication pumps for industrial machinery across India. Get in touch for specifications and pricing.