Beam Reflection

Morning Folks
Last night I had a project to do on 10 tumblers, they are stainless steel. I have Cermark and used it many many times, in fact I just did a beatiful job marking a name on Wustoff knives for customer. Now talk about being nervous because these knives are a couple hundo each but it worked. So now I prep the tumblers, wipe with alcohol, prepare the cermark mixuture same as always. I start to mark the tumblers and I see the air assist line going into laser head start to smoke than burst into flames.
Ive done many many reflective things before but never had this happen, has this happened to anyone before? Is that part of the risk with CO2 lasers and chemical marking? Could that beam have reflected up .005 and burned my retina?

This is the damage and in other pick lucky me found this at ace hardware with was a perfect swap for anyone looking to replace.

I’ve had reflection. I was testing aluminum at full power on my 150W machine. The head went over an arc on the front facing edge of the aluminum and while I was watching the test cut, my face began to feel extremely warm!

Although I disabled the interlock / lid safety, I NEVER OPERATE THE LASER WITHOUT THE USE OF EYE PROTECTION WHEN THE LID MUST REMAIN OPEN (such as when over sized material is being used).

I’m surprised to see you had reflection strong enough and still adequately focused to melt that elbow (especially considering the stainless was coated in Cermark).

To answer your question: YES! If you operate your laser without a layer separating you (or your eyes) from the beam, it can burn you (or your retina).

A lot can happen operating a reflecting beam of Light Amplification by Stimulated Emission of Radiation :slightly_smiling_face:. A mirror could move, a mirror could crack, your hand or face could obstruct the pathway, or the material / machine bed / honeycomb bed could reflect.

I don’t operate the machine very commonly with the lid open mainly because doing so makes the shop stink as the fume extraction wouldn’t work as well (and would also quickly suck out all of my heated or cooled air). But again, when I must (or when I am testing), eye protection is mandatory.

In the incident I described above, I in fact was wearing plasma cutting goggles as I anticipated extremely bright sparking on aluminum the same as I have engraving stainless. Had I not had eye protection, I may have severely damaged my eye sight.

yes that is why you should keep the lid closed. If it was closed you were ok, the beam would hit your window which keeps the beam in.

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