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So I laser weld, and beyond my own PPE, interlocks (gun won't fire if it's not touching metal, etc), the most important part of the whole setup is laser safety
by DannyBee 2y ago
So I laser weld, and beyond my own PPE, interlocks (gun won't fire if it's not touching metal, etc), the most important part of the whole setup is laser safety curtains.
Because it's a 2500 watt laser, if i didn't have laser safety curtains , the relections/etc could very easily blind someone at a fairly long distance.
The NOHD (nominal ocular hazard distance) is something like 10km (2500 watt laser, 0.06mm spot size, divergence is very very small). The actual hazard distance is shorter, but still, kinda crazy.
(as for why i have a laser welder - i got it cheap and besides the downsides above, it is very easy to weld ~anything without much skill. A person who has never welded in their life can weld sheet metal and have it come out basically perfect in 5 minutes)
- RealityVoid 2y agoI'm dying of curiosity how cheap a cheap laser welder can be.
- mdorazio 2y agoA quick search is showing me new machines in the $7k range. You could probably pick up a used one for a few thousand less. This is cheaper than I would have thought, honestly - a decent full MIG rig is not exactly cheap.
- DannyBee 2y agoThey are coming down in price very quickly. The materials cost is really not very high (no idea on the laser itself, but the rest is easily <1k. Probably <500.). The R&D cost was probably very high to start (but also coming down).
- supermatt 2y agoI don't have one yet so cant really advise on quality, but I was recently looking and you can pick up a 2.5kW laser welder from about $15k. They are slightly cheaper (around 12k) from alibaba, but then you will be looking at import duties, warranty complexities, etc
- HeyLaughingBoy 2y agoYeah, that's the problem with some of the more expensive Alibaba/Aliexpress stuff. The list price is attractive, but once you add in all the extras like duties, transportation from the port of entry to your location, warranty difficulty etc., there's not much price difference from heading over to the local Kubota dealership. Still, some of those little tracked tractors on TikTok are interesting. If I could somehow raise enough money to start importing them, I'm sure I could sell quite a few.
- ensignavenger 2y agoA lot of folks find those little chineese tractors at auctions in the US. There are folks who handle all the import and then resell them. Can be a great deal but many of them need some mods, like better cooling, to really shine.
- isoprophlex 2y agoThere's a killer Neal Stephenson plotline in here somewhere. Redneck protagonist zapping enemy drones with a modified laser welder.
- paranoidrobot 2y agoI had to look it up, because I thought that was what "Reason" was in Snowcrash. I was mistaken: Reason was a railgun.
- rtkwe 2y agoThe weird part of reason is it is also (in the family of) a mini gun with it's multiple rotating barrels.
- zokier 2y agoOh yes: https://youtu.be/xNmbvaUzC8Q https://youtu.be/xNmbvaUzC8Q This is why we can't have nice things
- trelane 2y agoAlmost a different Funranium post: https://www.funraniumlabs.com/2022/12/choose-your-own-radiation-adventure-anti-drone-radiation/ https://www.funraniumlabs.com/2022/12/choose-your-own-radiat...
- HeyLaughingBoy 2y agoHmmm. I'm black, but my wife did anoint me to the position of "honorary redneck" some time ago. Neighbor has stopped with the drone overflights of my property, but still, you're giving me ideas...
- DannyBee 2y agoSo, to clarify - what i have is a very nice IPG lightweld 1500 XR. They are normally not cheap (30k), and are very nice and well thought out safety wise. One of the fun parts when i lived in the bay area was that as companies got acquired, they didn't know what to do with the stuff they had before acquisition that isn't needed anymore, and it either sits in a warehouse, or gets auctioned off (or both!) So for example, at one point, Google (after acquiring terra bella and some other companies) had like 5 or 6 very nice 5 axis VMC's sitting around collecting dust. Each was worth well over 250k. They already had plenty of VMC's in the machine shop, etc, and didn't need these, and it was not worth the trouble to sell them. At least back then. In my case, I was able to get this welder for way less than half price. The lightweld's have come down in price over the years, and that will keep happening. They are pretty much the most expensive laser welders though, you can easily get one for 10k these days. The truth is, however, if you go cheaper than this, what often what gets overlooked is safety. So some of them in the lowest price range don't even require you touch the gun to metal before letting you fire, etc. All of them can weld the same, so if you go looking, look at other things too. THe other thing - one of the nice things about laser welding is that it's improving very fast. So similar to fiber, running multiple types of lasers or optics in the cable is not particularly more difficult than running one. They just add more fibers (it's not quite the only issue, but you get the point). Why does this matter? Because it means you can run another laser or something to monitor the weld and adjust parameters on the fly. Which lightweld and others are starting to do. So if you are moving the gun too fast/slowly, or got the power wrong or whatever, it will compensate automatically This probably won't ever happen on mig/tig. The lasers are heavily computer controlled already, this just adds a feedback loop. It also enables real time certification of a weld - see https://www.ipgphotonics.com/products/laser-weld-measurement https://www.ipgphotonics.com/products/laser-weld-measurement for an example (this is a separate product, but you get the idea) In any case, my take would be - if you want to play with them as a hobbyist, or have too much money, they are cool Otherwise i'd wait ~5 years and what you get will probably be 5-10x better for the same price.
- mhb 2y agoVMC == Vertical Machining Center PSWAATY == Please Say What the Acronyms Are. Thank You.
- abakker 2y agohttps://www.everlastgenerators.com/catalog/laser-welders https://www.everlastgenerators.com/catalog/laser-welders this is probably the easiest one to buy from a reputable (non alibaba) company. its $17k, so not "cheap", but hardly expensive. My gut says they'll be for sale at $2-5k within 2 years at the rate things are going.
- sph 2y agoNOHD = Nominal Ocular Hazard Distance
- DannyBee 2y agoYes. Sorry for not expanding it. I edited it to expand it. For others: The NOHD is really a nominal distance. It's just the distance at which the beam falls below the maximum permissible exposure. The 50% eye hazard distance (ED50) is 31.6% of this number. That is, if the NOHD is 100m, then at 31.6 meters you have a 50% chance of causing a medically detectable change to the eye. It's also worth noting - the beam power at this 31.6% distance is 10x, not 3x, what it is at the NOHD. For laser welding, the spot beam is small (60um) which is one reason the NOHD distance is so high. For reference, a laser pointer is like 1.5mm, so this is 25x smaller. It also doesn't help that the lasers used are all ~1060-1070nm wavelength and so invisible as well :)
- netsharc 2y agoSomehow your comment reminds me of Tech Ingredients grilling a burger with laser: https://www.youtube.com/watch?v=9VmITd0dKAo https://www.youtube.com/watch?v=9VmITd0dKAo
- exe34 2y ago> (as for why i have a laser welder - i got it cheap that's how a lot of good stories start
- dotancohen 2y agoYou don't want to hear how I met the ex.
- elif 2y agoPlease provide some more details on your laser welder. Did you import it from China? I want one so bad, but buying them in the USA seems to be 4-5x retail cost in China.
- tlb 2y agoWhy don't welding/cutting lasers add more divergence with built-in optics? Would it hurt performance? It seems like you could add 1 mrad and it would hardly make a difference at the usual working distance, but spread out to a meter over 1 km, so you can't zap people across town.
- queuebert 2y agoWhatever refracts the light will have to stand up to the beam for long periods of time. Maybe it's a materials science problem.
- eru 2y agoAs long as it doesn't absorb the light, it's fine. Just like the electric cables for your water kettle typically don't get hot.
- queuebert 2y agoYour kettle's power cable is sized to handle the relatively tiny current put into it, but even then it does warm up slightly. Try to run a million amps through it, and it will vaporize. This type of laser carries so much energy that even a tiny fraction of a percent absorption will add up quickly, hence the propensity for injury.
- oh_my_goodness 2y agoIf it's a 1-micron wavelength laser with a 60 micron radius spot, the divergence can't be much less than about 5.7 mrad half angle. What makes eye safety tricky is just that 2.5 million milliwatts is a lot of power. Even when you spread it out some.
- cwillu 2y ago‹twitches in metric prefix› 2.5 kilowatts. It's called 2.5 kilowatts. ‹calms down› 2.5 kilowatts is how much power a tea kettle in the UK draws. It's an insane amount of power to pump into a 60 micron point.
- notelectronic 2y agoI get laser safety curtains, but what do you do for reflections off the ceiling? Asking because our makerspace was recently donated a fiber laser welding unit and we don’t yet know best practices for not blinding our membership short of building a completely enclosed separate room for it with door interlocks.
- fasa99 2y agoWhat I do to match my lazer curtains is I hang a lazer tapestry off the ceiling to block all the lazers. I don't do lazer welding but I have lazer scissors and lazer axe which it is still useful for
- DannyBee 2y agoIdeally you have an enclosed area with interlocks. All of the laser welders support it (and it's the standard way). They make and sell mobile ones that can be pushed around. See, e.g., https://lasersafety.com/barriers/rigid-barriers/ https://lasersafety.com/barriers/rigid-barriers/ for some examples (I don't know these folks, they just have helpful pictures/listings of kinds of things that exist) If you can't do this, you do need to panel or curtain the ceiling or use laser absorption coating or other things. There are places that also just use reflection sensors that detect reflection on the ceiling and trigger (again, machines already support handling this). I have heard this works very well but have no direct experience with it. All that said, reflection off ceiling is more uncommon for practical reasons (The angle at which you hold the gun to the piece, the fact that ceiling directed angles often become back reflection into the gun which it already detects, etc). They already detect very high reflection as well. For a makerspace, one of the issues you will have is that people will likely want to try to weld copper and aluminum a lot, both of which are highly IR reflective. If you said "You can only weld steel and iron" you would eliminate a very high percent of reflection in the first place. Here's a basic chart that looks right: https://www.researchgate.net/profile/Tomasz-Kurzynowski/publication/234118523/figure/fig2/AS:300043786571777@1448547421302/The-absorption-of-laser-output-at-different-wavelengths-varies-according-to-the-materials.png https://www.researchgate.net/profile/Tomasz-Kurzynowski/publ... For a 1064nm laser, you can see Al or Cu is going to reflect a lot of the energy, while steel/iron are still off the graph high in absorption
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- hinkley 2y agoI had a friend, “Kevin” who got picked as a lab assistant for a guy making one of the first violet, and IIRC, picosecond lasers. It’s frickin’ laser beams so of course I had to ask way too many questions. They probably should have been using curtains but if they were he never said, and I’m sure laser safety has evolved with the wattage and commercialization, whereas this was a static benchtop system. There were lots of mirrors and prisms and they has to calculate refraction off of them and stick carbon blocks everywhere that light transmission was less than 100% efficient so that no light could escape the system except via the target.
- BonoboIO 2y ago10km … damn. And the biggest problem is, the danger is invisible.
- ziofill 2y agoWhat are the curtains made of? I’m surprised 2500W on 0.06mm don’t just go through like there’s no curtains