Laser fumes, and why extraction is not optional

A CO₂ laser cuts by burning a very small amount of material very quickly. Everything that used to be in the kerf has to go somewhere, and it leaves as smoke, fine particulate and vapour. Getting that away from the operator and out of the machine is part of making the machine work.

What the machine actually releases

The mix depends entirely on the material, but there are three things going on at once:

• Particulate. Very fine soot and ash, small enough to stay airborne for a long time and to be breathed deep into the lungs.
• Vapour and volatile compounds. Whatever the material gives off as it decomposes. Wood resins, acrylic monomer, binders and glues in board materials, dyes and finishes.
• Odour. The most noticeable of the three, and the one that causes complaints from neighbours, tenants and colleagues. It is the least important from a health point of view.

Different materials are very different. MDF produces far more smoke and resinous residue than solid wood. Leather and textiles produce a heavier smell. Acrylic produces less visible smoke but a vapour you do not want to breathe. And some materials must never be processed at all, no matter how good your extraction is. See which materials can you cut with a CO₂ laser.

Extraction protects three things

• You. Repeated exposure to laser smoke is a genuine occupational health issue. Smoke escaping the cabinet and drifting into the room means you are breathing it.

• The machine. The smoke inside the cabinet does not just sit there; it lands. It settles on the lens and the mirrors, where it absorbs part of the beam instead of passing it, so you progressively lose cutting power and the optics run hot. It settles on the rails and the belts. It gets into the electronics. A machine with poor extraction needs its optics cleaned constantly and wears out faster.

• The cut itself. Air needs to move through the work area to carry the plume away from the beam path. If the smoke lingers, the beam has to burn through its own exhaust, and both cut quality and depth suffer.

Smoke escaping the cabinet is a diagnostic symptom

If you can see or smell smoke coming out of the machine while it runs, extraction is not keeping up. That same smoke is landing on your lens. Treat it as a fault to fix. See my laser no longer cuts all the way through.

Ducted outside, or filtered?

There are two approaches:

Ducted to the outside. The extracted air leaves the building. Simple, effective, no consumable cost. It requires somewhere to duct to, and it means you are exhausting the smoke into the outside world, which may or may not be acceptable depending on where you are, what you process, and who your neighbours are.

Filtered recirculation. A filter unit cleans the air and returns it to the room. No ducting required, which makes it the only option in many rented or shared spaces. The trade-off is that filters are a consumable with a real running cost, and the unit only works as well as the filters currently in it.

To find out which recirculation setup suits your situation, contact us via the contact form.

Why airflow figures on a datasheet can mislead

Airflow is the figure datasheets lead with, so a high number looks like an extractor that will move the smoke away. That holds only if the pressure is right, because the airflow figure is guaranteed at a stated pressure. A datasheet should always give that pressure alongside the airflow. If that pressure is too low for the ducting, the resistance of the run cuts the airflow by more than the extractor can make up.

Getting the right solution for your situation

Sizing and specifying extraction depends on things that cannot be known from a web page: your machine and its power, which materials you actually run and how often, the room, the building, whether ducting outside is possible, what the local requirements are, and what happens to the air afterwards.

Getting it wrong is expensive in both directions: an undersized system does not protect anyone, and an oversized one is money spent for nothing.

Talk to us before you buy

We scope extraction case by case. Contact us and we will put you in touch with your account manager, who will go through your specific situation and recommend something that fits it.

Useful things to have ready:

• Machine model and laser power
• Which materials you process, and roughly how many hours per week
• Room size, and whether ducting to the outside is possible
• Any constraints from your landlord, your building or local regulations

On a BRM machine

Extraction is standard on every machine we supply, and its capacity is scoped to your situation at delivery, so the sizing is not left to you.

Technical documentation for the units we supply is under Downloads: BRM Extractor filter datasheets and specifications of non-filtering extraction.

Ducting, wall penetrations and the room’s fresh-air volume are part of preparing the site, and we ask about all three before delivery: preparing your workshop before the laser machine arrives.

The minimum, whatever you choose

• Extraction runs whenever the laser runs, not switched on once it starts to smell.
• Leave it running for a while after the job finishes to clear the cabinet.
• Keep the lid closed while cutting.
• Keep the bed clear of offcuts. They smoulder, and they produce smoke long after the job has ended.
• Check filters and duct runs on a schedule rather than waiting for performance to drop.
• If a material is on the never list, no amount of extraction makes it acceptable.

Related articles

• Preparing your workshop before the laser machine arrives - Space, route, power and extraction to sort out before delivery day