Oil Mist Extraction for a CNC Machining Enclosure
Project overview
A‑Mac Environmental was approached to design an LEV system to assist a company with its machine-shop operations, ensuring that they are carried out in accordance with recognised HSE standards. Its engineering facility provides multi-axis turning, boring, and milling services using modern CNC control technology as well as traditional manual machining.
The system was designed to control the fumes and oil mist produced during machining, clean the contaminated air inside the enclosed process area and return filtered air to the machine enclosure.
The Challenge
CNC machining can produce airborne oil mist, smoke and fine droplets as cutting fluids come into contact with rapidly moving tools and hot surfaces. If these contaminants are not effectively controlled, they can escape from the machine and affect air quality within the wider workshop.
For this application, the machining process operates inside an enclosure with no employee present while the machine is running. An effective push-pull ventilation arrangement was therefore required to remove contaminated air, filter it and return clean air to the enclosure.
The Solution
The system uses supply and extract grilles positioned within the CNC enclosure to create controlled airflow across the machining area. Contaminated air is drawn through the extract ductwork and passed through a Plymovent ME‑32 mist eliminator.
The filtration system contains three bag filters followed by three H13 HEPA filters, providing a stated filtration efficiency of 99.9%. Air movement is provided by a 7.5 kW direct-drive centrifugal fan before the filtered air is returned through the supply ductwork.
Pressure gauges are fitted across the filters to help monitor their condition and identify when maintenance or replacement may be required.
LEV Examination and Testing
Once the Equipment was built and in place, A‑Mac Environmental completed a thorough examination and test in accordance with the Control of Substances Hazardous to Health Regulations 2002 and relevant HSE guidance.
Airflow measurements recorded a duct velocity of 13.47 m/s and a total volume flow rate of 6,093 m³/hr. This exceeded the 10 m/s transport velocity benchmark for oil mist and fumes.
A qualitative smoke test was also completed inside the CNC enclosure. All released smoke was successfully removed within one minute, demonstrating effective air clearance and movement through the extraction system.
The supply and extract grilles, ductwork, filters and centrifugal fan were inspected and found to be in good condition.
The Result
The system passed its thorough examination and was assessed as providing adequate control of the fumes and oil mist produced during the CNC machining process.
The push-pull airflow arrangement effectively clears contaminated air from the enclosure, while the multi-stage filtration system removes oil mist before the cleaned air is returned. As the machine remains enclosed during operation, employees are also protected from direct exposure while the process is running.
The completed system provides effective contaminant control, supports cleaner workshop air and helps the customer meet their responsibilities under COSHH.
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Controlling oil mist in engineering workshops
A‑Mac Environmental provides oil mist extraction, industrial ventilation and LEV services for CNC machines and other manufacturing processes. Our services include system design, installation, commissioning, COSHH thorough examination and testing, maintenance and repairs.
Contact A‑Mac Environmental to arrange a site survey or discuss an oil mist problem within your workplace.