Didymium Glasses

[trussmonkey25]

I am using Co2 60 watt laser to freehand cut thin wood letters and shapes. I was wondering if Didymium glasses will be safe to use for better viewing of the work. the laser when it cuts makes a bright white glaring light. that makes it harder to follow my pattern. I don't know if the didymium glass will block the ir laser light or let it pass through the goggles

 

[Trevor]

Standard polycarbonate safety glasses block 10,600nm - it's not the laser light you're seeing as a bright white light.

The light is probably a byproduct of the cuts you're making.

As for blocking it with didymium... I'm not sure.

Trevor

 

[trussmonkey25]

Standard polycarbonate safety glasses block 10,600nm - it's not the laser light you're seeing as a bright white light.

The light is probably a byproduct of the cuts your making.

As for blocking it with didymium... I'm not sure.

Trevor

yes my question is will they safely block the ir or will the laser light pass through just like the optics of the system.

 

[Trevor]

I can't find a spectral analysis of didymium at 10,600nm.

It MAY block 10,600nm.

It WILL NOT block the bright white light you see when you cut. That is a broadband emission caused by the laser obliterating the material you're cutting - it is not IR.

Trevor

 

[Things]

yup, the white light you see is going to be composed of many different wavelengths, like sunlight. Your best bet would be to wear some sunglasses, or maybe light welding goggles if it's still too bright. Both will also stop 10600nm due to being made of glass or plastic anyway.

 

[trussmonkey25]

The didy glasses i seen used in a glass blowing studio. the glass getts white hot and hard to see the actual work. the dydi glasses aid by blocking certain bands 589nm and some higher ir and uv band. what I'm looking for is will they stop stray light from the laser its self

 

[ultimatekaiser]

I dont think that didymium blocks 10600nm light, but im not absolutely sure.

the primary purpose of didymium glasses as far as I know is actually not just to block out yellow, blue, and red wavelengths, but also to inhibit minor UV wavelengths... I used them whenever I used to do metallurgy/smithing to prevent arc eye, which is basically having sunburned corneas. It is created during the process in decent amounts and is reflected around the forge which it adds up cumulatively over time, and it hurts like heck.

If you were to buy it as a filter on polycarbonate safety glasses however as a coating, $60-120 USD I believe, the polycarbonate should block the wavelength, as other members have said.

it may reduce your work glare a bit, but i cant imagine that it will make it will make a huge difference as when the laser is striking the wood it's likely reflecting at a range of wavelength's like a light bulb would, and at high energy. looking at superheated glass and metal becomes more tolerable, but its still pretty bright, and fairly hard to look at for a long time. which often we dont have to do, as you have to work fast before it cools and becomes too hard to work with.


http://www.youtube.com/watch?feature=player_embedded&v=YxgFsYfDyoc

 

[Trevor]

The didy glasses i seen used in a glass blowing studio. the glass getts white hot and hard to see the actual work. the dydi glasses aid by blocking certain bands 589nm and some higher ir and uv band. what I'm looking for is will they stop stray light from the laser its self

Your CO2 cutter is already under an acrylic shroud, right? If so, that's already blocking all the stray laser light.

It seems that didymium is made of only neodymium and praseodymium; 10,600nm will pass through that with no problem. If it were mixed with ordinary glass, it would afford protection. But didymium glass on its own will not afford you protection against this laser.

As for the glare...

The didymium blocking the IR and UV does not help you see the work better - that light is invisible already. Didymium makes blown glass easier to see because it blocks 589nm - the wavelength emitted by hot sodium in the glass.

The glare you're trying to block is very, very broadband - not one wavelength in particular. Having very, very, very dark glasses will dim it enough for you to see the area where the cut is occurring, but you will not be able to see anything else.

Didymium will not solve either of your problems.

Trevor

 

[trussmonkey25]

Ill try welder's glasses first. i need to see the pencil lines where i want to cut. Thankyou All. That answered my question. I can't use the didy glasses alone.

 

[Bionic-Badger]

I wouldn't bother with welder's glasses either. Just get some thicker acrylic glasses -- thicker just in case it starts to melt without you being aware.

 

[sdistin]

10600nm doesn't pass through many materials well; that's why you need special optics to handle the beam. It's absorbed by polycarb, glass, your corneas...If you can get rid of the sodium emission and some of the carbon of the carbon emission it should help. but you already know that if you do glass blowing.

Surgeons who use only CO2 don't have to coat their O.R. windows: "The specific lasers to be used and the need for windows in the OR should be evaluated. For example, if only CO2 lasers are used, window coverings are not necessary because glass absorbs energy at the 10,600 nm wavelength. However, it does not absorb significant amounts of the 1,064 nm..."

Selection, Purchasing, and Use Considerations for Laser Safety Eyewear

 

[LSRFAQ]

The host glass for didymium mixes is a flint or crown glass. That alone will adsorb 10.6 micron radiation. The ions in the mix adsorb at a few bands in the visible, near IR and UV. There is a strong adsorption at 589, which adsorbs the sodium flare off from the molten glass. Glass and Quartz is mostly sodium, and the two orange lines at 589 are easily excited and very bright when its vaporized and heated. Thus glassworkers user Didymium around melts and for torch work to block UV to the cornea and the orange sodium flare. It does not help much with broadband light, it is a notch filter.

What you see when you cut with a low power CO2 laser is a broadband emission from glowing carbon dust. This is the ONE and ONLY case where a pair of low OD Green welding goggles will help you with a laser.

Safety disclaimer, don't use welding goggles with High Power Co2, YAG, DIODE, or FIBER LASER welding or cutting.

Steve