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FrozenGate by Avery

How many don't have the right Glasses?

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Jul 15, 2008
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I am convinced you need Glasses for cutting. My collection is a 5mW, and a 50 mW ( tested to be within +/- 5 mW) green laser pointer and getting a red 200mW burning laser, which I won't start burning until I get proper glasses.

Now my question is how many here say you need glasses, yet will be using the wrong ones, or cheap ones, giving false security to the eye.

Now this can be more dangerous then not wearing any glasses, simply for the fact you think your safe, so don't take any care or worry if you get a reflection back to the eye.

At least wearing no glasses. Since you know if you get a reflection back into your eye you will try to avoid reflection back to the eye.

I had read not only do you have to have the right wave lenght, but right density also for the laser your using, so for basically each new laser you buy, the chances are you need an indivual pair of glasses, so it's not a stright forward afair.

You may be wearing laser glasses, but the wrong type and desnsty for that laser, and that is a false sense of safety which is even more dangerous.

Ok what pair do I accually need for a red 200mW laser pointer? And where are some good places to buy them?

I don't want a flase sense of security. I know on here there had been the odd recommendation, but how safe is that reommendation, and are you accually having a false sense of security as glasses alone don't mean your safe if they are the wrong ones?

And can bet here some are using the wrong ones without knowing it, even though you know you need glasses, you need the right ones which is a study all in itself also to make sure you get the right one for the job and not assume just because they are meant for red, or green lasers they are safe?

So think maybe there are some myths even when it comes to glasses, would I be correct?
 





There is a large amount of disinformation regarding laser protection. Calculating OD is actually a very complicated process. For the hobbyist, however, using 10 seconds as an exposure time is quite appropriate.

The actual calculation looks like this:

OD_calculation.gif


The MPE varies depending on exposure time. It is broken down into .25 seconds which is the speed of the blink reflex, 10 seconds which corresponds to accidental exposure, 600 seconds which corresponds to testing such as aligning lasers for experiments, and finally 30000 seconds which corresponds to a workday of exposure such as in laser steel cutting plants, etc.

There are some other behind the scenes data that factors into the MPE such as the NHZ which is the nominal hazard zone of an operating laser. It determines the danger range of a direct exposure and the danger range of diffuse viewing.

For our purposes we can use the output of our lasers and figure the OD to attenuate the signal to class IIIa or better generally considered safe for viewing. As I state on a regular basis and to some, ad nauseum, just make sure your eye protection meets FDA or CE standards then you can be sure of the performance of the lens.
 
Just get a pair of these and you'll be fine. Anything with an OD of 3 or higher is plenty for a 200mW laser, that means that if you were to get hit with a reflection of lets say 100mW, the blast would be the equivalent of having a .1mW laser shone in your eyes.
One of the things with improper safety glasses is that your eyes will also be dilated, so your going to take in more of the reflection because the laser has a bigger area to travel through as opposed to having normal sized pupils.
 





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