LaserCanvas
Air assist and extraction: what each one does
Air assist is a jet at the nozzle that clears smoke from the kerf and keeps flame off the surface — it improves cut quality and reduces fire risk. Extraction pulls fumes out of the enclosure and outside the building. They solve different problems and you need both; neither substitutes for the other.
Two systems, often confused
| Air assist | Extraction | |
|---|---|---|
| Where | At the nozzle, pointing at the cut | At the enclosure, pulling air out |
| Protects | The cut and the lens | Your lungs and the room |
| If missing | Charred edges, flare-ups, dirty lens | You breathe the fumes |
| Typical kit | Aquarium pump or small compressor | Inline fan and ducting to outside |
What air assist actually does
- Clears the kerf. Smoke and debris in the cut absorb the beam. Blow them out and more energy reaches the material.
- Suppresses flame. Wood flares. A jet of air at the cut keeps a flame from establishing and travelling along the kerf.
- Protects the lens. The airflow pushes smoke away from the optics, which otherwise deposit on the lens and reduce power over time.
- Cools the surface, which reduces the scorch halo around the cut.
On wood the difference is dramatic — often the single biggest improvement to edge quality available. On acrylic it is more nuanced: strong air chills the melt and frosts an edge that would otherwise be flame-clear.
| Material | Air assist |
|---|---|
| Plywood, MDF, hardwood | Yes, strong — the flame risk alone justifies it |
| Acrylic, cutting | Gentle or off, if you want the polished edge |
| Acrylic, engraving | Gentle — clears debris without frosting |
| Leather, card, fabric | Yes — these catch light readily |
How much pressure
More is not simply better. The aim is a steady stream that clears the kerf, not a blast that scatters debris across the work or cools the cut so much it stops progressing.
- Aquarium pump — enough for engraving and thin material, and what many diode machines ship with.
- Small compressor, 15–30 psi at the nozzle — the usual range for cutting wood.
- If the cut gets *worse* when you turn air up, it is cooling the material faster than it is clearing the kerf. Back it off.
Extraction that works
- Duct outside. Through a window panel or a wall vent. This is the one that matters.
- Pull, do not push. The fan at the far end of the duct puts the run under negative pressure, so leaks draw air in rather than pushing fumes into the room.
- Short and straight. Every bend costs flow. A long flexible duct with four right angles moves a fraction of its rated volume.
- Seal the enclosure. Extraction only works if replacement air comes from where you intend, not from every gap around the lid.
- Run it after the job, for a minute or two, before opening the lid.
Common questions
Do I really need air assist?
For cutting wood, effectively yes. Without it the kerf fills with smoke that blocks the beam, edges char heavily, and flare-ups are much more likely. For engraving and for acrylic cutting it matters less, and for a polished acrylic edge you may want it gentle or off.
Is a recirculating filter enough instead of ducting outside?
Only for light, occasional work with a well-maintained carbon filter. Filters saturate, and once saturated they pass the fumes straight back into the room while looking exactly the same. Ducting outside has no saturation state to misjudge.
How much air pressure should I use?
Enough to clear the kerf and no more — typically 15 to 30 psi at the nozzle for cutting wood, and much less for engraving. If the cut gets worse as you increase pressure, you are cooling the material faster than you are clearing smoke.
Why does air assist make my acrylic edge cloudy?
Because the clear edge comes from the acrylic melting and re-flowing smoothly, and a strong jet of air chills it before it can. Reduce the airflow or turn it off for acrylic cut layers. Wood needs the opposite, which is why per-layer control is useful.