Laser Safety
I’ve seen a lot of videos on YouTube and LinkedIn showing various types of lasers used for adding variable information to products.  
Many of these videos show the lasers operating with zero protective guarding in place and operators not wearing protective glasses or goggles. 
This is entirely wrong – when installing laser systems for product coding, or for any other application, safety should be the single most important consideration. 
Uncontrolled laser light can cause eye injuries, burns, or even fires (yes, I’m aware of at least one instance where this has happened). That’s why there are rules that need to be followed, like the ones set by ANSI, OSHA or the FDA. 
The FDA categorizes lasers into four major hazard classes, each with specific safety concerns and control measures. These classes range from Class I, considered non-hazardous under normal operating conditions, to Class IV, the highest hazard class, capable of causing skin and eye injuries from direct and scattered radiation and can pose fire hazards. 
Packaging lasers are usually part of Class IV, and the object of laser safety guarding is to ensure the finished installation complies with Class I – non-hazardous under general operating conditions.
Guarding for CO2 Lasers: 
CO2 lasers emit light at a wavelength of approximately 9 – 11 microns in the far-infrared spectrum. This light is not visible to us humans. 
While it can undoubtedly damage eyes or skin with prolonged exposure, CO2 laser light, does not penetrate as deeply as light from other types of laser. 
Perspex, also known as acrylic or plexiglass, is used for guarding CO2 lasers primarily because it is opaque to the specific wavelength range produced by these lasers. Perspex can effectively block the laser radiation, protecting users from potential harm. 
When used as a shield, Perspex effectively protects against accidental exposure to the laser beam, preventing eye injuries and skin burns, and its transparency allows operators to see the work process while being protected from laser radiation.
Laser manufacturers offer a number of guarding solutions for CO2 lasers from simple Perspex cones that cover just the marking area, up to interlocked complete guards. 
 
Guarding for Fiber, UV and Green Lasers:
While simple perspex guarding works well with the light generated by CO2 lasers, it is not suitable for the shorter wavelength light produced by Fiber, DPSS, UV and Green lasers. This type of laser light passes right through Perspex. 
In addition, laser light of these wavelengths penetrates into the eyes and skin more than CO2 wavelengths – potentially causing damage to the retina. Retinal injuries can be more hazardous than corneal injuries, as they can lead to permanent vision loss. 
Ensuring complete guarding for these types of laser is a critical part of the installation since no laser light – either direct or reflected – can be allowed to escape from the system. This type of guarding should be used for all fiber, YAG, UV and Green laser installations. 
Stainless steel is often used to make these guards, but care must be taken with the design to prevent laser light from bouncing around inside the guard until it leaves the enclosure. Baffles are often installed to prevent this. 
Note that the guarding needs to be interlocked to disable the laser if one of the doors is opened. If the interlocks are overridden (say for setting up the laser head), it is crucial that the operator wears approved laser safety glasses – correct for the wavelength of the light being generated.
Outro: 
That's all for today's podcast on laser safety for coding installations. We hope you found this information helpful and that it will assist you in ensuring a safe working environment for your laser coding installations. 
When planning a laser installation, be sure your vendor is aware of the safety requirements and has a plan to ensure compliance with all the requirements.
You can learn much more about laser safety from the Laser Institute of America website. 
LIA can also provide training for you and your staff. 
Thank you for listening and we'll see you next time.