Safety Glasses/Goggles for CO2 lasers.

[ajf]

Hi all,

I got an email regarding the wavelength of CO2 lasers and the appropriate safety eyewear; thought I'd post the reply publicly as it's an important issue.

The wavelength of a CO2 laser beam is 10600nm.  You can google 10600nm safety glasses and find a range of safety eyewear from $25-$500+.  As far as I can tell all of the available glasses are polycarbonate, as such they would not be able tolerate a direct hit from the laser beam for very long.  Fortunately, with a laser cutter it is very unlikely that the operator would ever have their eyes exposed to the beam directly.  Reflected light could be an issue though, so glasses are good idea, especially if you are operating the machine with lid open for beam alignment or some other reason. However, I don't really see any need to spend $100s when the cheaper glasses are probably just as effective.

There is a good article on the NIH site which touches on this issue, it's mostly about various lasers used in medical applications, but the linked section discusses the effect of long wavelength beams on the eye. Good news: damage won't be permanent; Bad news: much pain.

Would be interested in hearing from others regarding eye protection.

regards,

aj

[John Dickinson]

Polycarbonate, 15 seconds directly in the beam.

http://imgur.com/h6xqqqt

Expensive goggles tend to be reflective so they can sit in the beam for an age and not suffer. Cheap ones (polycarbonate) absorb the laser power and do not reflect. This means that they will all fail once the molecules are excited to such a level that the integrity of the material cannot be preserved. Ordinary glasses will stop the laser, most things will but what you pay for is time, the more you pay the longer they will hold up.