Hi.
^This.
Tldr: If the reputable commercial laser safety glasses are out of reach for some reason, do use an enclosure.
The process can be monitored with a camera if needed.
For us more budget oriented folks, IMHO the only option for safe laser work with these low cost visible->low IR diode lasers is to put it into an enclosure of some sort.
Given the low budget requirements, itād be safe to assume that laser blocking transparent construction materals are out of the question :D.
My solution was to fabricate an ATA case/enclosure out of āfarmā plywood and AH extrusions+HW for my xTool D1 Pro.
Mainly because the xTool supplied glasses are advertised for 455nm only, so no dice with 1064nm, and also because I donāt necessarily believe the claims that they make on the supplied glasses either.
The added benefit of such an enclosure is the ease of transportation.
That ease will be obviously somewhat diminished when I fabricate one that can be used with the extensions.
Thatās about the only way to determine whether the glasses/goggles absorb the required wavelengths.
Easiest way to determine how much the lens absorbs, is obviously to compare a appropriate power level material test with and without the lens.
Other method would be to use any of the laser power meters on the market, but as Iāve not tested mine yet, hard to say if those work as intended, or at all for that matter.
Third could be to use optometrist or optician with the appropriate measuring devices, but I have no idea what that would cost or if theyāre willing at all to perform such a test for something that one didnāt buy from them.
Because of the geometrics and optics involved with at least all the lasers I know of, the glasses/goggles donāt need to be ruined in the test though.
Thatās a good thing because one never knows whether all the glasses/goggles from a certain budget store on the internet are actually the same as the ones bought/tested before.
One can test the actual pair theyāre using.
The following is in NO WAY intended as an excuse not to use goggles, nor to somehow give an illusion that itās all the same what to use, but just a quick brush up to the upper secondary school physics, and a reminder of what our diode lasers actually require eye protectionwise.
Unless one does something extremely ignorant -like use the laser head in a handheld fashion- the beam strength/area at 50-100cm distance from the focus point is something entirely different than what it is at the focus point.
Fortunately/unfortunately, whatever way one wants to think about it, we do not have the movie/comic book laser beams at our disposal.
We have an energy beam that resembles an X, with the focus point at the waist.
As an example, my xTool D1 Pro 20W 455nm has a ~0.1 beam diameter at the focus point, but 70mm further away that diameter is ~5mm.
So the area increases from ~0.008mm2 to ~19.6mm2, so ~2450 times the area and obviously the energy intensity is 1/2450 J/mm2.
At full 20 (advertised) watts that power does still very much scorch and gouge wood and such materials, so care have to be taken.
The reflected beam is another matter.
As soon as the ever expansing beam hits any surface, the reflection equations start to play a major role, obviously.
Depending on the material, some of the power is absorbed, some of it reflects fully, and some scatters.
While the reflected and scattered energy loses its strength rather quickly, it is still very much harmful to our eyes.
Mainly because our eyes are optical in nature as well, so the energy is again focused to a small area, thus increasing the power/area figure.
So once again, if the commercial goggles/glasses/masks are out of reach, do use an enclosure.
We have only one pair of eyes, and with a laser injury, the risk of losing or injuring both at the same time is IMHO way too great to ignore.
Regards,
Sam
), the coherent and more or less monochromatic nature of a laser -any laser- makes comparing the two a lot more complicated.
