61–70 of 378 posts
So after I got out I joined the National Guard.
Earlier quoted context omitted.
The sales guy set up the entire rig on his own? And no other engineers in the lab stopped to ask what he was doing? I know some places have poor safety culture, but this is a “laser company”. Basic laser safety should be drilled into them from day 1 and every day after. When I worked in an optics lab, we had interlocks on the doors that switched on with the power supply running the experiment and a sign outside indic…
It's pretty crazy that the sales guy was able to connect the water cooling and power with enough hosing and cables to bring it outside, as well as know how to operate the device enough to activate it - but couldn't correctly point it _at the ground_ and burn the paint off of the street without melting through a car. But forgetting that, what are the core safety issues described? I get the direct exposure to unprotect…
“Could we use this to burn paint off the road” sounds exactly like the sort of question a person doing a demo might say “I don’t see why not, let’s try it” to.
While with deliberate thought about it, the fact that road markings are retro-reflective is obvious, but it’s not something you would necessarily consider immediately, since it’s called “paint” and almost all paint you encounter in the world is not retro-reflective.
For the rest of it, my reading of the story is multiple things happened here:
1) They initially aimed the IR laser at the paint on the ground. The paint being retro-reflective the laser damaged itself in about an half hour and stopped producing consistent results, just occasional spots of results.
2) The sales person rather than halting the demo to get someone else to take a look at what was malfunctioning continued to fire the laser after making various adjustments not realizing that because the laser had been damaged it was firing not at the ground anymore, but at the car a few spaces away.
3) They’d been messing with the laser after malfunctioning since before the VP parked their car, so there’s possibility they were sending lasers in the direction of the other building, so that’s one issue which would have been bad enough on its own but…
4) At some point the VP parked their car in the path between the laser and the building. As they continued to mess with the malfunctioning laser, they burned through the paint on the side of the car, exposing the bare metal underneath.
5) The bare metal is also highly reflective, but because it’s not retro-reflective the problem is now you had completely uncontrolled reflections. The ones that went backwards had nothing to stop them since there was only a fence and field between the lot and the school. And the ones that went up obviously also had nothing to stop them since they were outside.
6) Because of the unknown detections and quantity of reflection, in addition to getting all the potentially exposed employees and customers checked out, the company would also have to make advisory calls (at a minimum) to the school and the local airports and military installations.
Whether those schools and planes were actually in danger or not could not be said with certainty, but the point was less “oh know we’re terrorists now” and more “this was a huge screw up, and I need to impress on you why it was bigger than just breaking company property or not wearing your safety gear”
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…
Earlier quoted context omitted.
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.
It's entirely possible that "Bob" is a generic name (using $SALES_GUY, like he uses $LASER_COMPANY and $FACILITY_GUY, would have been too repetitive). ...or the guy was really called Bob.
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…
NOHD = Nominal Ocular Hazard Distance
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 :)
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I'm dying of curiosity how cheap a cheap laser welder can be.
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…
Are you able to attach them to the heads of sharks?
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…
Then again, occasionally real life really does happen unbelieveably, including when fudge-ups are involved.
Maybe what's most unbelieveable is that, to the extent the story tells, the only known injured person was the laser safety officer.
Presumably the safety person was partly in the loop on some other injuries, but maybe they're NDA'd on that, yet not NDA'd on mentioning the incident. Or, maybe an incident like that was kept very quiet by a company, and injured people never knew how they got injured.
Then there's this:
> It has been brought to my attention that I have never actually written this story down before, merely told it in person to many students for valuable lessons and also for laughs over cocktails.
Did they only give verbal reports and verbal depositions/testimony? Never wrote up a report for internal use or for professional publication?
"Laughs over cocktails" could mean finding humor in the ridiculousness of disaster, and taking a battle scar in stride. Could also be a hint that the entire story is a fabricated/embellished/appropriated story, like people often tell recreationally when drinking, and understood in that context for what it is.
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…
VMC == Vertical Machining Center PSWAATY == Please Say What the Acronyms Are. Thank You.
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…
Yeah, the story contains some obvious bullshit. There is no way in hell a flashlamp-pumped Nd:YAG laser could cut through a piece of steel. With typical ~Hz repetition rate and ~J pulse energy, the average power is only around 1 W. This is three to five orders of magnitude lower than typical welding lasers. This could burn some paint or engrave metal, but burning through a wheel well and brake line is completely ridi…
Earlier quoted context omitted.
I'm dying of curiosity how cheap a cheap laser welder can be.
There's a killer Neal Stephenson plotline in here somewhere. Redneck protagonist zapping enemy drones with a modified laser welder.
I was mistaken: Reason was a railgun.