The topic of safety should always be first on your mind when it comes to laser cutting materials. The process of laser cutting uses focused heat energy to vaporize a material; this means we will possibly see small flames and certainly generate smoke.
Rule number one: Never leave your machine unattended while it is running. Many materials such as acrylic and wood are inherently flammable. Mechanical and electronic glitches happen on rare occasions and could cause a catastrophic event while laser cutting. Keep an eye on your laser company while it is cutting. This is the best way to respond quickly and to keep a small event from becoming a huge event.
Rule number two: Know what type of material you are laser cutting. Not all materials are safe for cutting with a laser. Materials that contain PVC or are made from polycarbonate produce caustic fumes when laser cut and should be avoided. Many laser system manufacturers clearly state that processing these materials with a laser voids the factory warranty, as they can damage the laser system with their fumes. My recommendation is always that if you do not know what kind of material you are working with, do not put it in your laser.
Rule number three: The exhaust system also plays a critical role in the performance and safety of laser cutting. The exhaust air flow should meet or exceed the laser system manufacturer’s specifications for both volume and pressure. A well-designed exhaust system removes the smoke and vapors from laser cutting and also reduces flaming. If you see smoke left in the laser system after cutting or a flame that comes close to the lens, then you need to improve your exhaust system.
Rule number four: If your laser is equipped with air assist, it is always a good idea to use it when cutting. Air assist is helpful to reduce flaming during the cutting process. Keep your air pressure low, as too much air pressure sprays residue onto critical components of your laser.
—Mike Fruciano, Coherent