How I got my laser eye injury

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, 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 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.

There's a killer Neal Stephenson plotline in here somewhere. Redneck protagonist zapping enemy drones with a modified laser welder.

I 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

A 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.

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.

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

Are lasers typically able to reflect off of surfaces that diffuse light (ie drywall)? I’m totally ignorant when it comes to laser safety, apologies if this is a stupid question .

completely enclosed separate room for it with door interlocks

You absolutely, absolutely need this. Do not take chances. "Real estate is expensive" is not an excuse for a blinding hazard to members and visitors of your space.

I've worked with very high powered room-sized laser cutters before and they should all have a full room enclosure.

Separate room with interlocking doors

-coming from another hacker space

Yes. 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 :)

You don't want to hear how I met the ex.

Cheaper ones often skip safety features like interlocks to so be careful.

The guy was listed as a "sales engineer" which on first glance is the worst sort of oxymoron, everybody knows engineers make terrible salesmen[1]. But perhaps it could work, just take your sleaziest engineer, put them through an intensive indoctrination in chicanery and lies and you get a salesman who almost knows what he is talking about.

1. How do you know if the guy trying to sell you something is the engineer. They will tell you in excruciating detail every flaw and design mistake in the thing and how they should have designed it better. Savor this moment, look past the terrible sales pitch and buy from them, for you have been gifted that elusive thing, the engineer.

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 unprotected eyes damage, but there's discussion of infra red reflections endangering nearby children + aircraft + casus belli with the US army.

I have seen a drunk employee wrestling with a moving industrial robotic arm trying to "fix it" after having disabled the numerous safeties with screwdrivers. This was at a major car manufacturer plant. Do not underestimate the horrible situations people can put themselves in.

I find this basics of this story believable. I worked at a place that manufactured IR lasers, and where the owner (the "Doctor" as we called him) set up similiar impromptu demonstrations that went awry. Thankfully no one was injured, but some random piece of equipment was damaged by the reflected beam.

Sales Engineer = Knows enough to be dangerous.

Sometimes a good sales engineer can tell you all about then undocumented feature you need to get something delivered.

With highly technical products usually you have at least two guys working on a account:

The salesman, who deals with the business guys on the other side, the folks who will actually sign the check. The sales engineer, that deal with the guys who will actually use the product, is able to understand their requirements and come up with ways the product can fullfil those, provide Proofs of Concept, demos and initial training for those guys on the other side that will give the final ok to the business people: 'this will work for us, you can sign the check if you want"

Mm.

Should be, isn't.

I've heard of one place that had a class IV laser mounted on a robot arm in a public area, which turned itself off when the arm happened to flail in exactly the right way to hit its own emergency stop button.

custom infrared -> green laser

Nd:YAG lasers always creep me out. I worked in a lab that had an Nd:YAG with two janky doublers: 1064 -> 532 -> 266 nm. The output energy was supposed to be a few mJ (IIRC), but it was basically zero. So the students operating it took off the second doubler and fired it at a bookend. Nothing (well, nothing visible). Took off the first doubler. After investigation, the zapping sound was the paint vaporizing off a computer at the other end of the lab, because the beam was actually scooting just past the bookend. 1064 nm is almost the worst wavelength you can work with. (Okay, 233nm is probably worse, but the available energy with a setup like this is much lower.)

I have a green laser pointer, and I made a point of buying a diode laser. It’s a slightly different color than 532, its battery life is better, but, critically, there is no way it could malfunction or be sloppily constructed to leak infrared light.

Crouch? When training technicians, the first thing is, you never ever bend your waist in the laser room, with lasers on. Your head never enters the plane of the laser beams. You do not put your ahead above the laser. You use a piece of copy paper to earache for stray beams near the apparatus. You use an IR viewer to (shock yourself as to how many there are to) find 1064nm stray beams.

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.

Yeah, I thought it sounded a bit too good to be true as well...

reads like a BOFH story

Was curious so I looked it up - Jose Antonio Vargas Elementary School is right by Moffet Field. The school also abuts an industrial park that fits the description.

One of the current tenants there is Volvo Innovation Lab, which I imagine does laser testing. I have no idea if buildings need certain certifications for working with lasers, so I mention that tidbit.

As well, that office park has 16 buildings in it, by my count.

The pieces of this story very much so line up.

He didn't claim it cut through steel, JGCs have polymer wheel wells and brake lines like most modern cars.

Maybe they meant the plastic wheel well liner? I don’t know if that makes sense, I’m just googling around looking at Jeep Cherokee images.

It's just there for flair. :)

possibly his boss asked him to not write up the report

I think they know that. I read their comment as sarcastic.

hull damage being caused or not caused by a rifle being fired from the flight deck of a ship

How did that happen? Our MarDet would occasionally do live-fire training off the flight deck (CVN-65); they naturally pointed their weapons away from the ship ....

Or are you talking about hitting the hull of a different ship, e.g., one of the tin cans in plane guard, or alongside during an UNREP? Seems like that would ... get noticed by a lot of folks.

Save $300 on a vasectomy.

I'm guessing there are other adverse effects beside sterilizing.

I thought the whole point of the Marines was to cause maximal amounts of damage.

I thought their point was to expose themselves to maximal amounts of damage.

Compton is a bitch for astronauts too.

I’ve seen some references to the universal laser glasses: Apple Vision Pro!

Dye lasers are the worst. You now have _two_ (or more) wavelengths to shield against. Bonus points if one of them is in IR.

That's probably how I got my eye damage - a small hole in the retina of one eye.

Because if you want to cover all possible lasers you'll block out the visible spectrum as well and won't see anything.

Then you can't see anything.

They're narrowband filters. A welding mask would be a wideband filter, but is much harder to work with when it's engaged.

Niiice. Even attenuates those xray lasers!

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.

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.

When I was ~12 years old one boy pinned me down and another one shone a laser pointer in my eye just for fun. Needless to say, this has been my „bad eye“ ever since (I’m 39 now)

A friend of mine gave me a high power blue laser pointer, and it was fun for a night but I gave it back to him because I recognized that it was just too dangerous. One slip, one stray reflection, and I'd damage my eyesight or go blind. It's just too dangerous, and I'm a very careful person who takes precautions - I can't imagine kids with laser pointers are going to be able to see very well when they are older.

Nd:YAG lasers such as the one in the article use an IR exciter into a crystal to achieve frequency doubling or tripling. Much of the energy from the fundamental exciter makes it past the crystal, so without good filtering, a "safe" class 2 or 3R laser can still produce blinding (but invisible) light. Lots of the cheap lasers don't have good filtering, so be careful what you buy.

Sometimes a funny story is one that helps you remember about safety.

No. That only says something about you, not “the culture”. It’s incredibly common to laugh at the absolute absurdity of a situation. It doesn’t mean that people are making light of it. It doesn’t mean that they don’t grok how serious it is. They just react differently to you.

If the Germans can joke about it, anyone can.

https://www.youtube.com/watch?v=xJ_86lxP36I

in a time when eye safety goggles were not used for visible light.

Also Yikes. Even with my low(ish) 1w-5w handhelds, it's self-evident that eye protection is needed when the beam travels less than a few yards.

It's a scanning dot moving fast enough to appear as a cone.

I'd wondered about the eye safety of LIDAR on prototype autonomous vehicles, but then thought "surely anything at all unsafe to eyes wouldn't be allowed on public streets."

Now I'm reminded of all the unregulated recklessness in some technical topics that I do understand, and realizing it's silly to assume.

https://www.youtube.com/watch?v=INFavIUmhcE

I remember reading a story of someone photographing a military helicopter (I think), only to find out that the crew apparently considered it funny to point some laser based system (likely a range finder or designator) at the photographer, burning the camera sensor to the point of damage being clearly visible on the sensor itself (not just the pictures).

then the third rule must be, "now you can do whatever the fuck you want" written in Braille.