The purity of the compressed air used by the milling machine shall be determined according to the specific process requirements, and usually meet the industrial standard to ensure the normal operation of the equipment and the processing quality. The following is an objective analysis based on industry practice:
main use of 1. compressed air in milling machine
- cooling and lubrication
- through the air cooling system, the temperature of the tool and the workpiece is reduced, and the tool life is extended.
- Spray trace lubricant (MQL) to reduce cutting heat and friction.
- Cleaning and chip removal
- purge the chips to prevent scratching the surface of the workpiece or blocking the machine tool guide.
- Clean the optical sensor or detection element to ensure the processing accuracy.
- Pneumatic control
- drive pneumatic clamps, tool changers and other actuators.
Influence of 2. Compressed Air Purity on Milling Machine
- oil content
- impact: The oil contaminates the cutting fluid, resulting in a decrease in cooling performance; it adheres to the surface of the workpiece and affects the coating quality.
- Requirements: usually ≤ 0.01 mg/m & sup3;(oil-free compressed air).
- Moisture content
- impact: Moisture causes corrosion inside the machine tool, shortening the life of precision parts; freezing and blocking the pipeline in low temperature environment.
- Requirements: Pressure dew point shall be ≤-20 ℃ (equivalent to water content ≤ 0.8 g/m & sup3;).
- Particulate matter
- impact: Particulate matter scratches the surface of the workpiece and reduces the machining accuracy; it blocks the pneumatic components and causes the action to malfunction.
- Requirements: Particle diameter should be ≤ 0.1 μm (corresponding to ISO 8573-1 Class 2 standard).
3. purity requirements for different scenarios
- precision machining scene
- application: Aerospace, mold manufacturing and other fields, processing accuracy requirements ≤ 0.01mm.
- Requirements: Cold dryer and multi-stage filter shall be equipped to ensure that the compressed air meets ISO 8573-1 Class 1 standard (oil content ≤ 0.01 mg/m & sup3;, water content ≤-70 ℃ dew point, particulate matter ≤ 0.1 μm).
- Common processing scene
- application: General machinery manufacturing, processing accuracy requirements 0.05-0.1mm.
- Requirements: Meet ISO 8573-1 Level 2 standard (oil content ≤ 0.1 mg/m & sup3;, water content ≤-40 ℃ dew point, particulate matter ≤ 1μm).
Risks and Solutions of 4. Purity Failure
- risk
- equipment failure: The wear of pneumatic components is accelerated, and the maintenance cost is increased by 30%-50%.
- quality defect: The surface roughness of the workpiece exceeds the standard, and the rejection rate increases by 20%-30%.
- Solution
- source control: Use oil-free air compressor to avoid subsequent degreasing burden.
- Post-processing system: Configure cold dryer, adsorption dryer, precision filter, etc. to purify compressed air step by step.
- Regular inspection: Use particle counter and dew point meter to detect air purity every quarter to ensure compliance with process requirements.
Conclusion: The purity of the compressed air used by the milling machine must match the processing accuracy. The precision processing scene must meet the ISO 8573-1 level 1 standard, and the ordinary processing scene must meet the level 2 standard. Through the combination of source control and post-processing system, the purity of compressed air can be effectively guaranteed, and the failure rate and scrap rate of equipment can be reduced.
