Buying an extractor with too little airflow means poor fume capture and smoke-filled workshops. Buying one with too much airflow wastes electricity and money. Here's how to calculate exactly what you need.

The Basic Formula

Required Airflow (m³/h) = Machine bed area (m²) × Capture velocity (m/s) × 3600 × Efficiency factor

Capture velocity is the air speed needed to pull fumes into the extraction hood. Industry guidelines:

Efficiency factor: 1.3-1.5 to account for duct losses, bends, and filter resistance.

Quick Reference: Machine Size → Airflow

Laser Bed SizeTypical MachineMin Airflow (m³/h)Recommended Model
300×200 mm (desktop)Diode/UV desktop marker200-40012-11, 12-1
600×400 mm (6040)CO₂ engraver, fiber marker400-60012-1
900×600 mm (6090)CO₂ laser cutter600-100012-1, 12-4
1300×900 mm (1390)CO₂ laser cutter1000-150012-4, 12-5
1300×2500 mm (1325)Large CO₂ laser1500-300012-5/5S
Multi-machine cluster3-6 CO₂ lasers3000-600012-6, 12-8
Hand-held fiber welder1-3 kW fiber1500-2000FH-8/8S

Duct Loss Calculation

If you're using ducting between the extractor and the laser, you lose airflow to friction. For every:

  • Meter of straight duct (150mm diameter): loses ~2-5% of airflow
  • 90° bend: loses ~10-15%
  • Flexible hose (vs rigid duct): ~3× the loss per meter

Keep duct runs as short and straight as possible. If you must go over 5 meters or have more than 2 bends, size up by at least one model tier.

Multi-Inlet Considerations

For extractors with multiple inlets (FH-8, 12-6/8/9), airflow divides across open inlets. A 2000 m³/h unit with 4 inlets open delivers roughly 500 m³/h per inlet. Close unused inlets with provided caps to maintain capture velocity at active stations.

Still Unsure?

Email our engineers at sales@reborixfume.com with your laser machine model, bed size, and what materials you cut. We'll recommend the right model — it's what we do every day.

Related Resources

How to Choose a Laser Fume Extractor

Read Guide →

ESP vs HEPA Filtration

Read More →

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