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How I got my laser eye injury

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Re: How I got my laser eye injury

#121

Post by antoinealb »

HeyLaughingBoy wrote: post #110
DannyBee wrote: post #50

Earlier quoted context omitted.

So, 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…

> plenty of VMC's in the machine shop So now I have to know why Google has a machine shop. Beyond the obvious "why not?"

Google as a company manufactures hardware, it makes sense to have a machine shop for prototypes.

Re: How I got my laser eye injury

#122

Post by ooterness »

NathanielBaking wrote: post #61

Safety guys always ruin the fun. I was in the Marine Corps and every time we got to test some new piece of gear the safety officer was like "No, you can't live fire it off the flight deck of the ship" or "No, not here, that village is down wind of the dust you will kick up when it goes off." No, that has a kill distance of 6 miles, you have to fire it into a hill." Blah, blah, blah. So after I got out I joined the Na…

I am reminded of the "Sir Isaac Newton is the deadliest son of a bitch in space" speech from Mass Effect 2.

https://youtu.be/hLpgxry542M?feature=shared

Re: How I got my laser eye injury

#123

Post by psd1 »

antoinealb wrote: post #121
HeyLaughingBoy wrote: post #110

Earlier quoted context omitted.

> plenty of VMC's in the machine shop So now I have to know why Google has a machine shop. Beyond the obvious "why not?"

Google as a company manufactures hardware, it makes sense to have a machine shop for prototypes.

Google was founded by burners who want to take cool shit to the desert.

Re: How I got my laser eye injury

#124

Post by justin66 »

dghughes wrote: post #57
dmd wrote: post #28

I'm not entirely sure, but I suspect my Hole In My Eye[0] came from being 30 years old (I'm 46 now) and saying "look, this laser pointer is so low power, I can shine it in my eye to no ill effect!". [0] https://dmd.3e.org/a-hole-in-my-eye/

At a casino where I was a slot tech we used fiber optics that went into a fiber converter module and then RJ-45. Often I would look at the ends of the fiber connectors to see if they were lit or if the light looked odd. They were quite low in power but I'm surprised at myself that I didn't think of the risk. edit: optics not options

Some scientists used to look at the beam emitter to adjust the aim of old particle accelerators. The story I heard was that some of them eventually developed cataracts as a result. Come to think of it, with today's medical technology that's a lot less awful than punching holes into your retina with a laser, but I think the result back then was eventually blindness.

Re: How I got my laser eye injury

#125

Post by foehrenwald »

mpalmer wrote: post #12
zoky wrote: post #3

I’m not saying it didn’t happen as described, but this really kinda reads like the “Bald eagle named Albert Einstein flew into the classroom” copypasta…

Never let facts get in the way of a good story. The build-up is great (VP's car, elementary school, military base) and the punchline is funny, but it's just a bit too perfect ("and what's above us?", cue clouds). Even the name Bob sounds like it's been chosen for comedy. It's clearly a mostly true story that's been refined and polished over the years.

reads like a BOFH story

Re: How I got my laser eye injury

#126

Post by wildzzz »

dghughes wrote: post #57
dmd wrote: post #28

I'm not entirely sure, but I suspect my Hole In My Eye[0] came from being 30 years old (I'm 46 now) and saying "look, this laser pointer is so low power, I can shine it in my eye to no ill effect!". [0] https://dmd.3e.org/a-hole-in-my-eye/

At a casino where I was a slot tech we used fiber optics that went into a fiber converter module and then RJ-45. Often I would look at the ends of the fiber connectors to see if they were lit or if the light looked odd. They were quite low in power but I'm surprised at myself that I didn't think of the risk. edit: optics not options

Patch fiber is usually using Class 1 or Class 1M lasers which are entirely safe to look at. Also the light spreads out very rapidly at the end of an unterminated fiber because there's no lens to focus it. So don't hold it directly up against your eye but like a foot away is fine. The lasers are less focused (i.e. cheaper) and the multi-mode fiber is wide so it spreads out very quickly. You can't actually see the IR light, the red light you see is just sidebands of the signal.

Fiber used for long hauls is much more powerful but uses a wavelength that the human eye is very good at blocking (so your eye dissipates more of the energy but what does get through could damage your retina). There are systems that will decrease the power if the link is lost (cut or unplugged) to protect eyes. The light will still dissipate in free space (because there's no lens) so you should be safe from a distance. Single-mode fiber uses a more focused laser and more narrow fiber so it will spread less over a free space distance so don't get too close.

Always better to just use a light meter (or a phone camera) if you're unsure but also just holding the end of the fiber against some paper or your palm may reflect enough of the visible light to let you know the fiber is live.

Re: How I got my laser eye injury

#127

Post by DannyBee »

notelectronic wrote: post #119
DannyBee wrote: post #17

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…

I 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.

Ideally 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/ 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/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

Re: How I got my laser eye injury

#128

Post by krisoft »

HeyLaughingBoy wrote: post #110
DannyBee wrote: post #50

Earlier quoted context omitted.

So, 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…

> plenty of VMC's in the machine shop So now I have to know why Google has a machine shop. Beyond the obvious "why not?"

They make hardware prototypes. When you do that having your own machine shop can lower the iteration time and thus speed up the development.

Just from the top of my head: waymo develops their own lidars, akamai obviously needed a ton of machining for the kite, project loon probably had machined components. And those are just the flashy examples we heard about outside of the company. They can have ton of other projects which didn’t get to the point where we heard about them but required hardware prototyping.

Re: How I got my laser eye injury

#129

Post by DannyBee »

HeyLaughingBoy wrote: post #110
DannyBee wrote: post #50

Earlier quoted context omitted.

So, 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…

> plenty of VMC's in the machine shop So now I have to know why Google has a machine shop. Beyond the obvious "why not?"

Lots of reasons. Prototyping consumer goods of various sorts, etc.
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