In all cases lasers use light energy to effect a change on a material being processed. In most cases this change is caused by the rapid heating and cooling of the materials being laser processed. Laser can produce heat energy in energy densities measured in the megawatts/centimeter squared (MW/cm2) in a relatively small heat affected zone (HAZ). At these extreme but highly predictable and controlled temperatures materials being processed by the laser may melt, burn, bubble, outgas, vaporize, smoke or fume.
A distinction must be made of the by-products of laser processing found in fumes or smoke. Typically there are larger than micron sized particles of the base material that get caught up in the super heated air vortex and these fall close to the cut area as they cool. Typically call debris, this by-product can be controlled but not always eliminated from the process.
Fume extraction is then mainly concerned about creating enough vacuum directly around the heat affected area of the material being laser processed to remove those gases caused when the material breaks down into a vapor, remove any smell or strong odor caused by this out gassing and capture those micron sized particles that can be taken up by fume extraction system.
There are several methods used to create proper fume extraction. These might include but are not limited to tip extraction, extraction hoods, down draft vacuum (open flat bed) and full enclosure evacuation and in some cases even room evacuation.
Each technique greatly affects the amount of air volume required to meet the minimum 0.5 m/s as set out by the British COSHH (LEV guidance notes) and the United States EPA Clean Air Act (CAA) and the U.S. Code (USC) for emissions.
Once the fume is capture it can be processed through a variety of HEPA filters (to remove particle contaminants) and charcoal filters (to remove smells and odors).
In all cases the experts at American Laser Welding can help you make the selection of proper fume extraction systems needed for your particular application.