40W CO2 laser with 10600nm wavelength.
K40 uses a laser with the wavelength of 10600nm. This kind of range should be covered by OD7+ according to the Internet.
I found OD4s which have the range of 5000-11000nm and are meant for CO2 lasers. I asked the retailer if these will suffice and why I don't need OD7+ if they'll say these will do. The OD (optical density) value is about how much light is kept out (99 % OD1, 99.9 % OD2, 99.99 % OD3, etc…) so I guess from some base safe OD value, the increasing OD value becomes about for how long the eye is protected in an event of a direct impact, but that's only a guess at this point.
K40 uses a CO2 laser and in case of a malfunction, it might release dangerous CO2 fumes. CO2 is not the same thing as CO so it's important to buy the right kind of a detector! Most people who have some kind of a detector already will have a CO detector, CO2 detectors are more expensive and harder to come by. I found one which should work for the K40:
K40 will also emit CO fumes in case wood it being engraved or cut. In case of other materials, various other kinds of fumes might be let out of the machine. It's not a terrible idea to get a CO detector in addition to the CO2 detector as it could detect improper ventilation of the wood burn fumes or a fire starting to develop in case the material being worked on catches fire. I already use a CO detector at home and will probably get the same one for the shop, too:
https://www.alza.cz/honeywell-xc100d-cssk-a-d5502997.htm
Ground the laser chassi so that in case of an electrical discharge through insufficient insulation, the machine doesn't discharger into you, the operator. It uses high value (even though with low current, but the current is direct - DC) and getting zapped by it could induce a cardiac arrest and kill you.
Do not leave the laser cutter unsupervised as the material being engraved or cut could catch fire which could spread.
It is a good idea to wire an endstop switch to the lid of the laser cutter in case the lid gets open while the laser operates.
Never run the laser cutter without the water pump connected and fully submerged in distilled water as it could significantly shorten the lifespan of the laser tube.
I'm not sure whether the K40 could handle cutting CCL, but there exist research which seems to look into laser cutting CCL which might be interesting to read:
https://link.springer.com/article/10.1007/BF02395722
- Get this on Scihub
Cutting and engraving CCL could be interesting if figured out how to do safely both towards the K40 (mirror and laser tube damage) and the operator (reflection increasing risk of eye damage). It could be used to engrave PCBs and even bore vias (although not plated). Theoretically, an entire PDB could be manufactured using the K40 alone with no other processing steps such as masking, washing, etching, drilling or milling.