Laser Safety - Make The Most of Your Home Laser Cutter or CNC Machine!

MicroCenterOfficial · March 2023

Written by Nick Biederman

As more home shops begin to use laser cutters, it's important to remember safety procedures. Like most other tools at our disposal, laser cutters are safe when operated correctly but can be dangerous if misused. Today we'll be addressing material hazards, fires, laser exposure, and other common hazards. Hazards and mitigation vary depending on the type of laser, so we’ll cover diode, CO2, and fiber lasers in this article.

While these tips are great ways to ensure your safety, they can't cover all niche cases. Be sure to read all documentation that comes with your laser for exceptions or additional safety tips!

Budget-friendly laser cutters, like the Creality CV-30, are becoming more and more common in home shops.

Material Hazards

As mentioned in previous articles, some materials are unsafe to process with a laser. Some materials, like vinyl, release gases that are toxic and can damage the laser. Others, like polycarbonate and some foams, tend to burn rather than cut or engrave cleanly. The Austin Makerspace has a good list of safe and unsafe materials in their wiki, which can be found here. While this list isn’t complete, it covers most common materials and is a good starting point if you’re unsure about the safety of a material.

Fumes

Choosing safe materials is an important first step, but you’re not out of the woods yet. Any material you cut or engrave will release smoke or other fumes. While these fumes may not be immediately hazardous, long-term exposure can be detrimental to your health. Ventilation is a must regardless of the material or type of laser you’re operating. The most common option is to vent the fumes outside. Depending on your laser, this can be accomplished with anything from a fan in an open window to ductwork leading outside. In general, more powerful lasers will require more ventilation. Enclosed lasers, like most CO2 lasers, usually have a place to connect ductwork for ventilation. Some have exhaust fans built in. Open lasers, like most galvo fiber lasers and many diode lasers, may require a bit more creativity. An aftermarket or DIY enclosure is one of the most effective options.

Enclosed lasers, like the TS3 from TwoTrees, make it easy to provide adequate ventilation.

If you’re unable to vent fumes outside, there’s a wide range of air filters available that will remove any hazardous fumes. These filters require routine maintenance to ensure they’re operating efficiently. The manufacturer should provide service intervals for cleaning or replacing filters.

Fires

Fires can occur while laser cutting. It's common to see small flames while the laser is cutting. As long as these flames remain small and self-extinguish when the laser stops firing, they're completely normal and no action is required. An air assist can help keep these flames to a minimum while also keeping smoke off your lens.

Some materials may smolder, but not ignite into a flame. If this happens, power off the laser, extinguish the smoldering material, and check lenses and mirrors for cleanliness. It's unlikely for a smoldering fire to do any permanent damage to a laser, but smoke can build up on optics and lenses. This can lead to reduced power output or damage to the optics. I have found smoldering fires to be particularly common with soft, lightweight plywood.

High-intensity fires are uncommon but can be extremely destructive. In just a couple of minutes they can ruin belts, lenses, wiring, and other components. The pictures below show the aftermath of a relatively small fire in my CO2 laser cutter that occurred while cutting acrylic. In the time it took me to get a cup of coffee the material ignited, ruined a lens and mirror, almost melted a hole in the lid, and melted a belt, some wiring, an LED strip, and the air assist tube.

I had already removed part of the laser head and the lens in this picture, but the damage to the belt and LED strips can clearly be seen here.

I was able to salvage the lid, but the fire nearly melted through it.

Here you can see the damage to the air assist tube, LEDs, and wiring for the laser pointer.

Fires can occur with any material. If you experience a flaming fire in your laser cutter, immediately unplug the laser and extinguish the fire. I highly recommend keeping a fire extinguisher near your laser. Most household fire extinguishers use a dry powder to smother fires. While this is very effective for a wide range of fires, it makes a mess that is difficult to clean up. CO2 and Halotron are alternative extinguishers that use gasses to extinguish flames, which will dissipate without leaving any residue. And don’t forget a smoke alarm!

Laser Radiation

One of the most obvious hazards is exposure to the laser itself. Eye exposure can cause immediate blindness, and skin exposure can cause burns.

Almost all laser cutters, including this Thunder CO2 laser, are Class IV Lasers.

CO2 lasers are generally safe as long as all covers are closed and the interlock on the lid is not disabled. Their fully enclosed design minimizes the risk of exposure during normal operation. Some operations, like using a passthrough to process large pieces, involve partially opening the enclosure while the laser is running. It's important to wear protective glasses while performing these operations. Though it may be tempting to bypass interlocks while performing mirror alignment or other maintenance, doing so will dramatically increase your risk of injury from exposure to laser radiation. CO2 lasers generally do not come with safety glasses, but they’re readily available. You’ll want a pair with an optical density of at least 6 that’s designed to provide protection from 10,600nm radiation.

Many diode and galvo fiber lasers do not have enclosures. This dramatically increases the risk of exposure to direct or reflected laser radiation. Safety glasses designed to protect from laser radiation are a must if you'll be working around lasers without an enclosure. Diode and fiber lasers generally come with safety glasses. It’s worth double-checking the wavelength of your laser and verifying the glasses you buy will provide adequate protection. Making or buying an enclosure is another good option. Micro Center carries a simple and inexpensive enclosure that will work with many diode lasers, which is available here. An enclosure will help protect you from laser radiation, and most incorporate ventilation. Unlike CO2 lasers, these enclosures rarely have interlocks that prevent the laser from firing if the enclosure is open. If you open the enclosure while the laser is running, you risk exposing yourself to laser radiation.

An aftermarket enclosure such as this one from XTOOL provides ventilation and reduces the chance of exposure to laser radiation.

Diode lasers often come with a small magnetic shield that connects to the laser source. These shields can help reduce the change of exposure to the laser, but do not provide adequate protection by themselves.

Since different types of lasers operate at different wavelengths, you’ll need to match the glasses you use to the laser you’re operating. A pair of glasses that provides protection from a CO2 laser might provide little to no protection from a fiber laser. You should be able to get the wavelength of your laser from the instructions, the label on the laser source, or the manufacturer. Any laser safety glasses made by a reputable company will clearly list the wavelengths they provide protection from.

While reflected radiation can be harmful to your eyes, it’s unlikely to damage skin. Care should be taken to keep your body out of the path of the laser beam, but no other precautions are necessary to avoid burns or other injuries.

More information on Class 4 lasers can be found at Laser Safety Facts. If your laser has a laser pointer in addition to a high-power laser source, you might want to review their page on Class 3A lasers as well.

Other Hazards

Most other hazards are not unique to laser cutters. Laser cutting can produce sharp edges on some materials, which creates a cut hazard. Glass can shatter if you overheat it while engraving, which also creates a cut hazard. Cutting or engraving metal can generate enough heat to cause burns. Moving parts can create pinch hazards. It’s impossible to list every possible hazard you might encounter, but as long as you operate your laser cutter with the same care as any other tool you should be able to avoid other hazards you may encounter.

Intense, concentrated heat while engraving can shatter glass.

Laser cutters are versatile tools that can add unique abilities to your home shop. These unique abilities also bring some unique risks. With proper setup, material selection, and protective glasses when necessary, these risks are easily mitigated and make laser work a safe and fun hobby