Open vs. Enlosed Lasers
The choices for hobby lasers are daunting. One of the major considerations is choosing between an open or enclosed laser area. In the end I almost always suggest an enclosed system for safety. Regardless of the material you are engraving or cutting with your laser there will be micro particles generated. It could be in the form of dust or soot from cutting wood, tiny particles of metals when engraving or newly created chemicals when working plastics. Every material generates something. With an open laser these particles are released into the environment the laser is kept in and are likely being taken into your lungs.
Another issue with open lasers is exposure to the laser beam. Fiber, UV, CO2 and diode lasers are all highly concentrated beams of light. Despite the concentration of the light into the small beam there is still some level that escapes the beam. Exposure to the beam can be harmful to living things in different ways. Exposure to the beam has obvious danger- it can burn the skin and dependent on the power cause deep burns through the skin. You do not want to have a laser beam meant for engraving cross your body!
Eye safety is critical. Most enclosures for lasers are made of non-flammable materials that block the laser radiation and protect your eyes from flash. The concentration of light that makes the laser beams is often visible and dangerous to your eyes. Our eyes are not capable of accepting the intensity of the beam and could be permanently damaged from even a brief exposure. Even invisible portions of the laser beam can cause serious damage to your eyes. The flash caused by the laser interacting with the material created a flash that is also intense.
There are a few arguments for open laser for engraving or cutting. The size of the material may limit the use of an enclosure. Portability also is limited with an enclosure. Regardless, safety needs to be a priority with an open laser- protect your eyes with appropriate safety lenses and use an exhaust near the laser to minimize dangerous fumes and particles.
One thing needed with either an open or enclosed laser area is an exhaust or fume extractor. Those particles need to go somewhere. The most efficient method is to exhaust them to the outside using a powerful inline blower. Then venting should have considerations for flow and makeup air (It will be sucking air out of the enclosure and drawing in replacement air from the room. This will impact the rooms temperature and pressure. If the room is sealed well it could create some crazy issues like doors being difficult to open. Just try and think everything through when setting up.). You should also check local building codes on venting setup.
As a last resort a fume extractor can be used if you absolutely cannot vent to the outside. A word of caution- extractors are expensive and not very effective. Rather than venting to the outside they vent to a box containing multiple levels of materials meant to trap the particulates. Many also contain activated charcoal for removing toxic substances from the air pushed through the filter box. The cost of replacing the filters is typically high and frequent. My biggest issue with fume extractors is their efficiency and the false sense of security they provide. The filters quickly become loaded with particles while the amount of draw from the enclosure drops. I have yet to see an extractor that does not “bleed” particulates out its exhaust into the room. Extractors almost assure you will be inhaling harmful materials.
There is little debate that an enclosed, properly vented enclosure is the best. While to upfront cost is higher the benefits are worthwhile. Protection from the laser and control of particulates are the major benefits to an enclosed laser.
