Dry CNC machining produces fine particulate (often in the PM2.5–PM1 range) that stays suspended and spreads quickly. Beyond respiratory risk and WEL considerations, airborne dust reduces machine reliability and product quality. The priority is to control movement of air and continuously remove the suspended fraction.

Stabilise airflow and pressure

Keep the machine area under slight negative pressure relative to adjacent spaces so dust moves inwards, not out. Use existing LEV or a dedicated extract to create a directional flow from clean corridors towards the CNC and out through filtration. Avoid free-air numbers; check airflow under load and maintain make-up air so doors still close easily.

Position and operate air scrubbers

When source extraction is limited, add air scrubbers to reduce airborne concentration. Place the intake close to the main leak paths (doors, cable glands, chip conveyors) and the outlet pointing away from people to prevent recirculating dust back across the breathing zone. Create a gentle “pull” past the operator. An air scrubber such as a MAXVAC Dustblocker can be used for continuous background reduction; choose units that accept high-efficiency final filters (H13/H14 where fine or carcinogenic dusts are involved) and monitor pressure drop as filters load.

Integrate the three-layer approach

Capture at source: fit tool-mounted extraction or redesign cuts to lower dust release and reduce spindle speeds where quality allows. Capture in the air: run scrubbers or negative air machines continuously during and after machining to manage peak loads. Capture on surfaces: vacuum settle-out using an industrial M- or H-class unit; avoid sweeping and compressed air which simply re-aerosolise dust.

Measure and verify

Use a particulate monitor to compare background levels before, during, and after machining. Aim for stable downward trends during production and a rapid decay once the job ends. Simple smoke tests show whether airflow moves from clean to dirty zones. Keep a quick log of filter changes, pressure readings (Pa), and cleaning intervals to spot drift.

Practical takeaways

• Create slight negative pressure around the CNC to contain dust.
• Place air scrubber intakes at leak paths; direct discharges away from people.
• Select high-efficiency final filters (H13/H14 as risk dictates) and track loading.
• Use industrial vacuums for housekeeping; never sweep or blow down.
• Verify with a PM meter and simple smoke tests; adjust placement accordingly.

Consistent airborne control cuts operator exposure, protects equipment, and keeps nearby processes clean. Pair sensible airflow management with routine verification and you will see fewer dust complaints, cleaner finishes, and less unplanned maintenance.