Filters remove the contaminants from the airstream so that clean exhaust air can be recirculated back into the workplace without the need to vent to the outdoors, hence the term “ventless.” There is a minimum of three stages of filtration for laser-specific applications.
- Pre-filters remove the majority of the dust generated by the laser process. These usually have a minimum efficiency between F8 and F9. Less efficient filters work to a certain extent, but allow the HEPA filter to block prematurely, which ends up costing more in the long run.
- HEPA filters remove the finest of respirable dust particles with an extreme efficiency of 99.999% at 0.3 micros.
- Gas filters remove volatile organic compounds (VOCs) and odors. They contain a mix of industrial-grade activated carbon and chemical oxidizing additives. Activated carbon is a wonder material that has a unique internal micro-structure that locks VOCs deep within it. The additives increase the spectrum of capture, which is required given the wide range of VOCs generated in laser processing.