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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 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)

Why 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.

If 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.

‹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.

This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

It's actually only americans who unaccountably make do with these horribly underpowered kettles. The rest of the world wants their tea and they want it now...

Technology Connections did an excellent video on this: https://www.youtube.com/watch?v=_yMMTVVJI4c

tl;dw -- kettles in the U.S. only take about 4+ minutes to boil a liter of water. So when you say "now" you really mean it.

I live in the US and have an induction stovetop. It can dump 3600 watts of targeted heat into a pot of water. It can boil 2 liters of water in ~3-5 minutes.

Plus, when you reduce the heat the heat reduces almost immediately.

Nothing else compares with the speed it works that I've ever used before. Definitely worth the upgrade in time saved at the stove.

I just nuke a mug of water for a minute or two when I'm making instant coffee. I never understood the big deal about electric kettles.

A water kettle lets you consistently heat water to the same temperature (not just boiling, high-end kettles have additional temperature options), regardless of:

- Amount of water

- Initial temperature of water

- Position of water container

They also prevent superheated water accidents.

Yes and: Kettles are much easier to clean than microwave (interiors).

Well our kettle is 2.4kW, our microwave is 800W or so effectively. Also our induction stovetop is much faster, so the nuking option is slowest by a lot.

Boiling water in a microwave does not make the microwave dirtier.

In fact if it boils it can help clean it!

True. The mess comes from a son reheating food, often tomato sauce based, without a lid.

most lid are plastics, so i suggest people heating without lids. Cleaning mwave is east anyway. I am sure ppl don't want microplastic laden food.

Better that than reheating it in a kettle!

Microwaving has the undesirable side-effect of also heating the exterior of your beverage's vessel.

Electric kettles make it easy to pour for pour over.

When the other options just need to be poured, waiting 4.5 minutes for boiling alone is a significant waste of time.

You can improve that by using less water, but I would still like to double the power.

Interesting what power do microwaves in US deliver. In EU the regular micros are about 900W range give or take 200W (that is 1500W from wall because microwaves are not efficient machines) but kettles have usually range 2200..3000. So it is obvious why everyone uses kettles. I myselft have 3kW one and it heats 0.35 litres to boiling in 51 seconds. To have similar microwave it would have to be 3000W micro that is 4500W from wall and have not seen that kind of monsters, also regular 1 phase EU socket delivers max 3600W so that limits it also.

A typical US microwave draws 900-1100 watts too. I can't even find a 2000-watt microwave listed for sale in the usual consumer places. That'd be like a "pro chef" level luxury item, likely needing beefier electrical wiring and so on. US electric code requires a dedicated 20-amp circuit for microwave, which isn't supposed to serve a 2000-watt load.

> it is obvious why everyone uses kettles. I myselft have 3kW one and it heats 0.35 litres to boiling in 51 seconds.

Wh? It’s definitely less hassle, and maybe faster, to fill a cup/mug and stick that in the microwave

Than it is to fill a cup, pour that into the kettle, boil it, then pour it back in the cup. Or you have to put more water into the kettle than you need, because you can’t measure it accurateLet, and then it takes longer to boil

Standard wall outlet in the US is 15 amps, so a maximum of 1800 watts. 20 amp outlets (which can supply 2400 watts) are getting common, but I've seen very few home appliances that actually use the extra amperage (as determined by having a plug keyed for such an outlet).

The back of the envelope comparison isn't difficult. The energy in different forms are doing the same thing.

Doesn't your microwave heat a cup of water in about the same amount of time as a tea kettle? And most tea kettles are bigger than one cup.

Now, think about concentrating the same amount of energy to heat up your eyeball. Or worse, concentrated into a tiny point on your eyeball.

Brits don’t mess around with tea I guess. I believe they’re mostly on 240v even for residential there. Correct me if I’m wrong but I don’t think it would even be possible to heat water that fast in the US on 120v.

Correct, it takes about twice as long to boil a kettle in the US. But the US is the anomaly here. Most countries use 220-240V mains like Britain [1].

[1] https://en.wikipedia.org/wiki/Mains_electricity_by_country#T...

British outlets are individually fused so they're typically rated for more current

British outlets are fused for _lower_ current than american outlets, not more: 13 amps instead of the 15 or 20 that's common here. It's the voltage that's higher, which means that the power transferred for a given current is about double.

Fused for 13A running off 32A ring main.

Continental Europe uses 16A radial circuits so the current rating is higher there.

EDIT: Of course, you can't run two kettles on one radial, but you can on one ring.

Technically, the US does as well.

You have 240 V at the panel, but you only run half for each common circuit.

Technically basically all buildings in Germany (residential and commercial) run on 400V 3 phase power. But access to it via sockets is only common in residential homes via sockets in a garage. It gets more common with car charging although they rather use 3 x 230V as far as I am aware of.

Fun fact: 400V 3-phase and 3x 230V are the very same thing. You'll get 230V AC between Neutral and each of the three phases, but the AC voltage between two of the phases will actually be 400V.

I'm living in apartment block built in 2016 in eastern EU and here every apartment has a separate 3 phase(5 pin) socket for the stove. It is a 7kw beast, it can easily destroy regular aluminum-steel pan if you put it on max heat. Steel part will fall apart.

Same in Eastern Germany, at least up to the 2000s. (Probably still, but I left, so can't vouch.)

I seem to remember our electrical stove and oven back in Germany in the 2000s using three-phase power.

Here in Singapore I think our pool pump uses three phase power, too. (Our plugs and outlets here in Singapore follow the British model.)

They have a man watch the telly to hit the button to turn on the power for all the teapots going on. https://www.youtube.com/watch?v=slDAvewWfrA

That poor operator probably gets an adrenaline rush (and finger twitch) every time he hears the Eastenders theme tune.

Assuming perfect energy transfer (fairly reasonable for conductive heating of water) with no losses to ambient, a starting temperature of 20 C, 1 L of water (which I assume to weigh 1 kg) and a 1800W kettle (the max you’ll find in America): no.

t = specific heat capacity of water * mass of water * degC deltaT / power

4.186 J/gC 1000g * 80C / 1800 J/s ~= 186 seconds

Higher, that would be quite an extraordinary microwave (probably too high) - 800W to 1kW at maximum typically.

(I use mine mostly on the 90W or 180W settings, for defrosting.)

I recently bought a 3500 watt electric kettle out of the bargain bin in LIDL, for around 20 euros. Europeans do not mess around when it comes to hot beverages

Yeah funny, i was going to say 2.5 kW kettles are a britishism and the ones on continental europe are weaker...

... but then i checked my eastern european kettle and guess what, it's ... 2.4 kW.

> This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

Almost all household appliances that heat (and specifically heat food or water) will operate at the limit of what your house can supply.

So that's about 1800 Watt in the US and about 3500 Watt in most of the rest of the world.

It's only natural that you see almost any (heating) appliance cluster around these numbers.

(I'm actually not quite sure where you would see 2500 Watt kettles. Perhaps some are deliberately neutered a bit, so that you don't blow a fuse in case you have anything else on that circuit?

Keep in mind that in the UK, but not in eg France or Germany, every plug also has its own fuse.)

I found it odd that in the US most home brewers don't use electric, but as you say they are limited by the elements they can use.

Here in the UK, my home brew beer set up has a 3000w option - great for boiling 25 litres of water/wort - that said it came with a EU plug with some sort of 'fancy' UK plug convertor. After about 4 years the plug started to get so hot that it melted a socket or two - I found that inside the convertor the connection between the EU plug and the UK was really thin, which was causing it to heat up.

I cut off the end of the cable and rewired it to a heavy duty UK plug - it has been perfect since then - and no longer over heats.

Electric is growing in popularity. It’s not overly expensive (compared to the cost of the gear, anyway) to get a dedicated 30A or 50A 240V circuit installed; or you can brew next to your washer/dryer, since there is nearly always a 240V circuit available there.

> I found it odd that in the US most home brewers don't use electric, but as you say they are limited by the elements they can use.

Yes, but you still see electric space heaters. And they essentially all also have the same wattage: the limit of what they can get.

british household AC is wild, it's like they've got a full-power american range plug for every outlet

Not just UK, the whole world except North America and Japan.

South african plugs are rated 16A @240V. Thats a safe 3.5kW at each and every plug socket in the house.

> Not just UK, the whole world except North America and Japan.

Brazil is also an exception. The standard socket is only 10A (with a 20A alternative for things like air conditioners), and the voltages vary depending on the city (and the building, and location within the building); you might have 110V, 115V, 127V, 220V, 230V, and perhaps others I have missed (I went in more detail about it at https://news.ycombinator.com/item?id=40385851). I live in a 127V/220V area, so my single-phase sockets are 10A @ 127V, for a total of only 1.3kW each.

So it's pretty normal for a "230v" plug to actually be anything between 220v and 240v. Voltages fluctuated pretty wide depending on location. It's all down to the loca transformers.

But mixing 100s of volts with 200s of volts sounds mad. I presume you had the special plug for your 200 range outlets? Does Brazil also have split phase AC like the US?

> I presume you had the special plug for your 200 range outlets?

The same type of socket is used for "110V" (usually 127V) and "220V", sometimes in the same building, sometimes right next to each other. The "220V" socket might be colored red, or might have a sticker saying "220V" glued next to it, but don't count on it. The only difference is between the 10A and the 20A, the pins on the 20A plug are slightly thicker and don't fit in the 10A socket (the opposite works fine).

But at least, it's better than a couple of decades ago: on top of all that, back then we didn't even have a plug and socket standard. It was a mix of several types, including a "universal" socket which looked like the common USA socket but could also accept plugs with round pins, and all of them (including the USA standard sockets) could be used for both "110V" and "220V". The new plug and socket standard is great; it's better than the USA standard, since a partially pushed plug won't expose live pins (and it's also slightly smaller, allowing for denser power strips). It's unfortunate that they didn't also modify the European standard they used as a base to add keying for the different voltages (while allowing a universal plug for things which can work on both voltages), but I understand that trying to do too much could make it politically unfeasible to mandate the new standard.

> Does Brazil also have split phase AC like the US?

It's more common to have three-phase AC (that is, between phase and neutral is 127V and between a pair of phases is 220V), but we also have some places with split phase (for instance, 110V between phase and neutral and 220V between a pair of phases).

I remember watching a Technology Connections video where he was looking at space heaters rated for small/medium/large rooms and pointing out that the medium/large room heaters were both 1500kW (iirc) as it’s the maximum continuous draw from a US socket.

Over here in NZ we get pretty similar ratings on the same style heaters, but the large room ones are 2400kW because we can get that from any socket.

Also with my hobby - sewing. A lot of people in North America talk about forgetting they left the iron on, but I switch it on and off every time because it heats up in 30 seconds - less if it’s been on recently.

And because nearly every single house in UK is wired for single phase only, your connection to the grid is usually rated at 80-100amps(so a regular British home can draw around ~20kW on a single phase).

And just like Americans have special access to 'full-power', there's special access to three phase 400 V in many nominally 230V countries, too.

That's eg common for electric stoves in your kitchen.

When we discuss laser power, damage begins in the milliwatts range, so those of us in the hobby prefer to state it like that so we can easily give people an idea of how fucked they can be if they treat a laser like a toy.

2.5 billion microwatts.

Sure but how many millijoules per day is that?

216 billion.

<twitches in metric prefix>

60 micrometres. "micron" is a deprecated irregular word that is unlike every other scaling of the metre.

Listen, our shoe sizes are measured in barleycorns, so we’re doing the best we can to adopt metric in places.

Correct me if I'm wrong "micron" IS metric (decimal based system) but it's NOT an SI unit?

Eh. At least this one is just a name. I don't know how precise we have to be in a blog post, you know? They're the exact same unit.

On the other hand, 2.5kW of light is not outrageous. It’s not drastically higher than some of the larger theatrical lights. (Not that being in a spotlight is pleasant, but it does not permanently blind the actors.)

A lot of this comes down to wavelength. Some wavelengths get focused by one’s eye and can concentrate their power in a small spot on the retina. Other wavelengths will be absorbed before they get to the retina and will therefore deposit their power over a larger area and in less sensitive tissue.

It can also make a difference if the light is pulsed.

Are you sure that's actually 2.5kW of optical power? Non-scientific lights aren't usually rated by optical power, but by electrical power.

But isn't stage light labeled for consumed power, not emitted power?

that's what i was going to say. and while you can use barn doors and lenses to hone the throw (the size of the beam on stage) -- it's not collimated like a laser is. even with parabolic reflectors like par cans. we're talking magnifying glass and the energy at the focal point (minus what the air absorbs for a given wavelength etc)

I'm not an expert here. But according to https://en.wikipedia.org/wiki/Diffraction-limited_system (see last paragraph of the intro) the diameter of a laser beam doesn't impose a diffraction limit on the optics it goes through. You still get the angular resolution you'd expect given the entire aperture of the lens even though the beam is only going through a small area of it.

Whatever refracts the light will have to stand up to the beam for long periods of time. Maybe it's a materials science problem.

As 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.

Your 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.

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

I tig. wear a helmet and have to buy argon every year. this seems like a huge hassle in comparison. is there that big a difference in quality and or range of processes that make it worth it?

I know one of the reasons we wanted pico-second and shorter pulsed lasers is that they can cut material with little to no damage of the neighboring material. There was a demo that I read about when this was all brand spanking new research, where they claimed that a laser scalpel causes no heat damage to tissue outside of a cell’s breadth from the contact point.

Here's a figure comparing the hole left in a metal surface with normal and femto-second pulses. The difference is quite stark.

https://www.researchgate.net/figure/SEM-image-of-the-substra...

Is it this?

https://en.wikipedia.org/wiki/Coulomb_explosion

It's related, but as i recall the reason that short pulses cut better has to do with heat transfer. Most heat transfer in metal is due to the vibration in the electrons, being much lighter than the atomic lattice they move in. Very short pulses, means that the heating in the beam path happens faster, than the electrons can transfer it out to the rest of the metal. In long pulses once the metal is vaporised, a lot of the surrounding material has melted. This molten metal cools into jagged structures and that leaves the edge weird. All this doesn't happen if the pulse is short enough. It vaporises metal before the surrounding structure has a chance to heat up.

Here's a figure showing the quite stark difference. https://www.researchgate.net/figure/SEM-image-of-the-substra...

Awesome, those photos do illustrate the difference really well.

Thanks heaps. :)

That's how LASIC and PRK work, after all!

its the operator skill part when dealing with thin sheet metal. It just works better / easier / faster for thin stuff, where in TIG, that's the high-skill work that everyone pays big bucks for.

Agree with the post above, though. The safety setup for lasers is basically full isolation.

seems like its more cost effective to just stay on or above 20ga unless you're really high volume or you really need the weight savings

> 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.

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 .

Do you see a bright spot when aiming the laser at drywall? If the answer is yes, then laser light is being reflected into your eye.

Hope this helps!

> Do you see a bright spot when aiming the laser at drywall?

It was red for a second but now what appears to be a black hole is consuming everything.

Congratulations, you've made your eyes laser-proof then! From now on, you can safely look at high-powered lasers.

This subthread is perfect for training AIs. Google, found it yet?

It's not that simple. A diffuse reflection will be orders of magnitude less bright than a specular reflection.

For a very wide range of laser powers (not 2.5kW), the trouble is in guaranteeing a diffuse reflection.

I’m confused. This is true from every angle from which you look at the wall right? So there has to be quadratically less reflection than e.g. a mirror, but still a lot more then a completely black surface.

The inverse squared falloff from a diffuse surface is not enough to prevent eye damage if you're in a regular-sized room, and playing with a class IV laser, or even some class IIIb lasers (depending on the distance, and the duration).

Got it, thanks!

Surfaces may produce diffuse or direct reflections (or more commonly, a mixture of both) for any light source. If you can see it, it's being reflected.

And even if you can't see it. You won't see a spot from an IR laser while it's burning the hell out of your retina. Which is why many (but not all) IR lasers co-produce a visible spot so you can see where the dangerous beam is.

>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.

That is the only way to not blind your membership.

What 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

Separate room with interlocking doors

-coming from another hacker space

NOHD = Nominal Ocular Hazard Distance

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 :)

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, 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.

VMC == Vertical Machining Center

PSWAATY == Please Say What the Acronyms Are. Thank You.

> PSWAATY

I'm keeping that one.

Usually i do, but there is one acronym in the entire 450 words, and it doesn't really matter to the point what the thing was?

If the definition doesn't matter, better to use a more generic term than a more specific/cryptic one.

OK. Thanks for the informative post. Don't want to discourage you from more.

I agree with you.

It's also pretty easy to figure out what you're talking about from context.

It's the second post in which he did this. And how should anyone know whether it's important to know what it means without knowing what it means?

I'm of the opinion that the guy or gal is giving us valuable information so let him rip instead of asking him to change stuff. If we can't google a simple acronym with the right context which we already know, we're on the wrong site.

> 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.

Duh! Of course!

I think Google and I only think search/ads. I forgot Alphabet has all that other stuff going on.

So does Alphabet.

All other projects are on the cancellation list, so don't worry overmuch about them.

IIRC it was started in earnest for Nexus phone prototypes in the early 2010s.

We had one at the Facebook offices too, as a side-effect of the Oculus acquisition. Hardware prototyping is fun

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.

They are in the rich people’s glamping camp. They haven’t lifted a finger on the playa, ever.

Google used to indulge employees' interests. They fund, or used to fund, "the generator", a build shop in Reno. I know a Googler who openly worked on a small art project at the office, albeit a small part of the work.

I'm not saying that Google has machine shops purely for burning man. But I strongly suggest that when the idea has been floated in various locations, one recurring theme is "yeah let's! And let's get some lasers and propane burners!", and I also believe that some managers were thinking "great, this is the culture we want."

The register calls it "the chocolate factory" as a reference to Willy Wonka. Shame they descended into evil.

I don’t mean the rank and file but Page and Brin. They’ve only ever gone the glamping sparkle pony route.

> I'm not saying that Google has machine shops purely for burning man. But I strongly suggest that when the idea has been floated in various locations, one recurring theme is "yeah let's! And let's get some lasers and propane burners!", and I also believe that some managers were thinking "great, this is the culture we want."

There was! It was the predecessor to the Garage. I suspect because the machine shop boys wouldn’t let them use the real toys.

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

> 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.

Darn, we were trying to get a mill for the NYC office's makerspace. It was probably a safety issue and not a parts procurement issue, though.

I see a bunch of them for about 1k on aliexpress. Any thoughts on those? I realize getting the cheapest possible unit is probably not the safest idea with laser welding.

> So some of them in the lowest price range don't even require you touch the gun to metal before letting you fire, etc.

Are you able to attach them to the heads of sharks?

If you can get them to stay still long enough, maybe.

PSA: Sharks die quickly if you get them still. Their heartbeat is connected to the swimming motion.

Some sharks have to swim to move water over their gills. Not even close to all of them and it's not due to their heartbeat being connected to their swimming.

https://www.britannica.com/story/do-sharks-really-die-if-the...

Thanks. In my defense, I heard this from my diving instructor who is a marine biologist.

It is a thing. It's just not as universal as people try to claim. There's a lot of biology in the marine world. No one can be an expert on all of it.

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

Yeah, 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.

A 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.

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

Hmmm.

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...

Be careful as far as the FAA is concerned drones get the same legal protection as a plane with people in them so messing with them is legally hazardous.

I know. Hence the laser: blind the camera first and they can't prove that it didn't mysteriously drop out of the sky as soon as it passed the property line.

Go get em cowboy!

Oh yes: https://youtu.be/xNmbvaUzC8Q

This is why we can't have nice things

It's rare to have such a clear illustration of the difference between intelligence and wisdom.

There's no way this stuff isn't giving the secret service nightmares.

This guy set ablaze the inside of a vehicle through closed windows from a significant distance.

I had to look it up, because I thought that was what "Reason" was in Snowcrash.

I was mistaken: Reason was a railgun.

The weird part of reason is it is also (in the family of) a mini gun with it's multiple rotating barrels.

I feel obliged to mention that this does feature prominently in Kim Stanley Robinson's Red Mars trilogy. The single most important piece of infrastructure on Mars is a space elevator, but not everyone on the planet is happy with how the owners of the space elevator are running things.

Almost a different Funranium post: https://www.funraniumlabs.com/2022/12/choose-your-own-radiat...

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.

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.

They 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).

I 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.

What are the curtains made of? I’m surprised 2500W on 0.06mm don’t just go through like there’s no curtains

hopes and seams

Maybe it just diffuses the beam?

Somehow your comment reminds me of Tech Ingredients grilling a burger with laser:

https://www.youtube.com/watch?v=9VmITd0dKAo

Please 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.

I wouldn't get one from China, no matter what the price is. Money can't buy eyesight, not in this case at least

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

> (as for why i have a laser welder - i got it cheap

that's how a lot of good stories start

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

10km … damn. And the biggest problem is, the danger is invisible.

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 National Guard.

I may or may not be aware of hull damage being caused or not caused by a rifle being fired from the flight deck of a ship. My point being, your safety officer had a point.

> 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.

Hypothetically, someone could have left a guest (like say an engineer from the shipyard doing sea acceptance testing) fire a rifle and an unlucky wave reflection might have bounced a round back towards the bow.

Wow what an incredibly unfortunate hypothetical situation. 1 in a million ricochet that one.

Draw a ship. Draw some waves. Note the angle from Crayon Eater those waves.

Also note how wide an angle "ship hull" represents both vertically and horizontally.

Not so 1 in a million.

Sure, if it bounces that's a very big angle.

But what's the chance of a bullet that hits water bouncing back the other way at high speed? I would have thought it was zero!

Would love to see someone fire a Phalanx for four hours just to generate enough test data to assess that probability

Seabees doing seabee things.

"A wave? At sea? Chance in a million."

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

It's really, really close though. The kill distance of six miles is what tips me over the edge of reading it as sarcasm.

Really? To me, it is a very clear instance. Amongst my cohort, saying "The safety officer won't let us do anything fun" is going to generally always be sarcastic, unless the point is that some rules seem excessively and obviously pointless, which these aren't. It's more a backhanded way of saying "thank goodness the safety office stopped us / those boneheads from doing something that would have been incredibly stupid."

It depends totally on how you read it. In this case, my first thought after reading that was "play stupid games, win stupid prizes". There are plenty of people (especially on the internet) who actually do think that way -- by which I mean people that are serious when they respond with "you guys ruin all the fun" to others who bring up genuine concerns that will most likely have wide-sweeping ramifications.

> There are plenty of people (especially on the internet) who actually do think that way

Sure. That's why these safety officers exist. I think some other funranium posts state.that (paraphrased) "safety rules are written in blood."

That said, I suspect folks like that would tend to phrase the rule in a way to diminish the implied impact/likelihood, rather than enhance it or state as-is, as (afaict) the original did.

like finishing a comment with, "we walked away with all our fingers -- perfect to flip the safety officer the bird"

OK, you have a bunch of kids, who, under different circumstances, might be playing grabass on campus, instead, are in charge of incredibly deadly stuff.

What could possibly go wrong?

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

Compton is a bitch for astronauts too.

It's all fun and games until you walk in front of a live AESA radar and sterilize yourself.

Save $300 on a vasectomy.

Mine was $750 :(

I guess if you only do one testicle, you may get half off.

They're about twice as much where I live!

Most US insurance will cover this at 100% even if you haven't met your deductible. Something about how babies cost more than a 3 digit outpatient procedure....

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

Is it scientifically proven though? If it that powerful wouldn't it cook your brain as well?

If the radar is located on the ground, the chances are it's consuming enough energy to cook a turkey from the inside-out.

Yeah, but one that immediately make you sterile will likely burn out your eyes and cook the brain. In any case I was just pointing out this is urban legend of sorts.

I always thought "make you sterile" was meant to be pronounced "burn your dick off".

> that village is down wind of the dust you will kick up when it goes off.

I'm always happy to hear that there are people saying these sorts of things in the military. I'm sorry it wasn't fun at the time, but the Safety Officer really was looking out for you. You really don't want to be the unexpected cautionary tale, like Bob.

> 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...

I thought the whole point of the Marines was to cause maximal amounts of damage. Are you implying there is a constraint on that?

But now I understand why the marines hate the navy: I had a buddy who'd been in the navy and he said they kept the kids busy by cleaning and painting everything but frequently they'd let 'em blow off steam by tossing cardboard boxes and stuff off the end the flight deck and shooting at them with the 50 cal machine guns.

We were good friends, attended MIT together, but if I thought the Navy would take many people like him I'd doubt their ability to fight a war. He was only in the navy because it would pay for school and AFAIK he managed to avoid getting any rank advancement at all. MIT requires, or used to, a lot of all nighters and he once said "I'm probably only sane with these all nighters because I did so much extra sleeping in the navy"

> 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.

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

I hate to be pedantic, but technically the whole point is to expose the enemy to maximal amounts of damage. Whoever that is. Anything else is incidental.

I'm referring to them being the tip of the spear, but yes, you are not wrong.

> But now I understand why the marines hate the navy: I had a buddy who'd been in the navy and he said they kept the kids busy by cleaning and painting everything but frequently they'd let 'em blow off steam by tossing cardboard boxes and stuff off the end the flight deck and shooting at them with the 50 cal machine guns.

If anything this should be why the taxpayer doesn't like the navy.

I’ve always assumed this kind of stuff is cheaper than the damage they’d cause if they were idle.

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My electronics mentor worked at 3M in the 80s. One of his coworkers thought it would be funny to prank him by asking him to look into a piece of equipment with something like a binocular microscope that the prankster had rigged to flash laser light at the sample. (I'm not sure what the equipment was, maybe something to do with chip lithography or looking at the surface of a magnetic platter.)

Somehow 3M was able to get out of compensating him for this workplace injury even though, if an ophthalmologist were to give him an eye exam (he tells me) they can literally read lithography writing (albeit backwards) burned in scar tissue on his retina. IIRC the prankster was never appropriately disciplined either.

Like OP it mostly affects/affected his peripheral vision and he just ignored it much of the time, but as he's gotten older his eyesight in general has gotten worse such that he can no longer compensate for it.

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/

One of the things I hate most in tourist hotspots these days are the people selling high powered laser pointers, normally selling them to kids, and they are shining it at their faces, in the faces of others, and at the neighbours.

I swear they never used to be so commonplace.

Having worked nightclub lighting a long time ago I have a deep appreciation for laser safety haha

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)

That's terrible, and I'm guessing they faced little if any consequences for it. I'm mad thinking about this, even though I wasn't involved and it was 27 years ago.

I would like to think that people would know today that laser pointers are weapons so this wouldn't happen, and that if it did happen, the schools' zero tolerance policies (the ones that you hear about used to stupidly expel someone for bringing a butter knife to eat their lunch with) would kick in, as school bullies literally damaging your body for life is completely unacceptable.

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Out of your ten comments, half are flagged. I propose that the lesson to take from that is to reread the guidelines¹ and adapt, not triple down on the same thing and complain.

¹ https://news.ycombinator.com/newsguidelines.html

And it would be a wasted life, just ask Jesus.

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.

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.

As an intern moving data centers the old networking guy told me to look into them; I used my right eye and now my eye is 20/40 a decade later whereas my left eye is still 20/20. I did hold it up to my eye because it was hard to see..

Just in case, always use the same eye to look into these things.

"Do not look into laser with remaining eye"

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.

I met a scientist who looked into a particle accelerator; it was intention, part of a self-experiment to establish whether high energy particles can cause scintillations in the eye. In his case he very carefully calculated how to get a safe dosage.

On the other hand there's https://en.wikipedia.org/wiki/Anatoli_Bugorski

“Low power” lasers are sometimes wildly more powerful than they claim to be. I guess what do you expect when you buy a Chinese laser pointer on Amazon for 5 bucks.

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.

Don't forget that the power rating of a laser pointer (unlike literally every other type of light you buy) is the output power, not the input power! More importantly, it's the output power of only the green laser!

The 1064nm exciter laser is pumped by an 808nm pump laser, and based on what I know about how inefficient lasers are, I can guarantee that those beams are way more powerful than the output beam! If those leak because the manufacturer cheaped out on filters, those lasers mat not visible, but they are still dangerous!

Oh yeah, that’s a real problem for cheap green lasers. IR diode laser, doubling crystal, and no IR filter is a good way to go blind.

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.

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.

Yeah like I said I'm sure it's mostly true. I just don't necessarily buy that he had a comedian's delivery on the day in question

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.

Also, the guy had enough happen to him. He doesn't need his actual name put in the story. One might hope that in the intervening 25 years he would have improved, especially after such an expensive lesson.

reads like a BOFH story

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

As I read through it, it does sound like an apocryphal old story, since too many of the details are too perfect setups for the teller.

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.

> Did they only give verbal reports and verbal depositions/testimony? Never wrote up a report for internal use or for professional publication?

I read that line as being in the context of the authors blog. As in “I’ve referenced this here before, and told the story to people in person, but never written out the story here on my blog.” Not literally saying that this is the first time in history any part of this story was committed to some form of the written word.

possibly his boss asked him to not write up the report

Yes, I don't want to speculate, but would hope that, for whatever happened, the affected people were notified, and all the appropriate safety officer processes were followed up on.

Or, the story might have started a bit like when grandkids ask grandpa how he got that arm injury, and instead of telling the troubling story about shrapnel in the war, or the car crash, he tongue in cheek tells a fantastic tall tale of fishing, when along comes a bear who wanted to eat his fish, chock full of lessons.

That could've been a goal with students: if one ran out of real-world case studies to drive home laser safety practices, a semi-plausible, if over-the-top, narrative of how a not-unlikely cavalier mistake could become a clusterfudge, with the story of course hitting all the safety practices they were just told about.

There would normally be verbal cues as to the kind of story, and there'd be the context of telling, both of which are lost in blog posts.

I worked for a few weeks in a class with a custom infrared -> green laser. The teacher were very hard about glasses, how to crouch looking away from the laser table, close the door and a few more security measures. And later, I had a 5W (0.5W?) green laser at 3 yards pointed at me [1] with some optical equipment bolted to the table in the middle so there was (almost) no possibility that it hit me.

The story sounds real.

[1] If all the bolted devices in the middle magically fall down, the laser would have hit my belly, not my eyes. So it's important to crouch looking away, just in case.

> 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.

Replying to myself:

I just searched Amazon. There are plenty of green “diode” lasers, 532nm, ~100mW, for very little money. I don’t believe that for a second — those are surely crappy frequency doubled Nd:YAG lasers, probably unfiltered (that filter wouldn’t be cheap, and it might fail anyway under that ridiculous power level), and they will blind you when some funny reflection of the, I dunno, 500mW of stray IR light hits your eye.

Now that real name brand laser pointers are mostly gone, if you actually want green, get a 515nm laser or something along those lines. Stay away from 532nm!

I have a friend with multiple green and red lasers, some from aliexpress.

Years ago when the hype wasnt really there he visited me and wanted to show off. I have 3 dogs and I really like this kind of tech but I forbid it to turn that thing on near me, especially in my flat. Even if they are directed away, the chance of unpredictable reflections is just too high for a bit of fun.

> (Okay, 233nm is probably worse, but the available energy with a setup like this is much lower.)

How do you get 233nm lasers?!?

Excellent question. You frequency-double 532nm and make a typo. I meant 266nm.

There are crystals that have nonlinear responses to high electric fields, and if you hit them with enough laser light, some of it comes out at half the wavelength. A lot of it also comes out at the original wavelength. Most 532nm lasers work like this, but other input wavelengths are possible, like starting at 532, doubling again, and getting 266nm.

This was a long time ago, and it wasn’t my project, so it’s possible it was slightly different, but I definitely remember the 532nm stage. And 266nm sounds credible for what the group was trying to do with the laser.

I understand the frequency doubling (/me points at my own eye damage).

I'm just surprised that you were able to make a laser with such a short wavelength with frequency doublers (or triplers).

There are some recent papers on doing it, and they even seem to have gotten decent efficiency.

The lab I was in was doing this in 2000, and I suspect they got their frequency doubler from some other lab. It worked, but it certainly didn’t work well. The 1064nm laser was decently large (a couple J per pulse, from vague memory), and the expected UV energy was quite low. The laser was being used for some form of imaging at short range (fluorescence or absorption in burning gasses? Maybe Raman spectroscopy if everything got lucky?).

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.

I agree. I'm not a native English speaker, so I may have choose the wrong verb. Is "squatting" better?

And with that kind of care, like turn everything off and still be very careful if you have to pick something from the floor.

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 indicating which wavelengths were operating.

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.

My dad was such an engineer doing sales, of industrial components. Grew up on a farm, engineering degree, very honest type churchgoer and family man, and in his spare time DIY projects like a classic engineer type. I'm sure he'd know when something would or wouldn't work, and would candidly tell the customer about any problems or risks. (In this case, maybe honest as much as an engineer personally bothered by design flaws.)

I've also seen a different kind of engineer in sales, where they're paired long-term with salespeople. They sit in on sales meetings as a technical expert, and also do things like customizations and integrations. I suppose the presence of the salesperson helps suppress the engineer's inclination to start riffing on every flaw, but the pairing retains the engineer ability to help the customer be successful with the product.

Yeah, I am a bit rough on sales, but it is critical to doing business. And a good saleman is a wonderful find, talking with someone who is knowledgeable and honest about the product is great.

You're littering via middle school group stereotypes for professions.

You're walking it back a bit by saying you're a bit rough on sales, but what you actually wrote is engineers are bad at sales.

Sales engineer is a well-populated role, and they do their jobs as expected.

On average, an engineer will be worse at sales than a "pure salesman", but that's simply specialization in action. Can't get better at what you don't have an opportunity to practice. We all can do pretty much whatever we want if we put our minds to it.

Sales engineers are very common if you are selling complex industrial products. At a certain point of complexity, selling a product and designing its integration with the customer kind of bridge. You need a deep understanding of the product and process involved to be able to sell it.

I've worked with a few sales engineers by now because I'm the person they try to sell to. I always saw sales engineers as the result of companies realizing that by now they often have to deliver sales pitches to engineers and not just manages managers and procurement folks.

In my case, that's exactly what they need. Sales people creep me out and make me want to hide under my weighted blanket. Sales engineers are the blessing that makes sales calls informative and bearable. I don't know how companies find and recruit them, but they make it happen and I'm very happy they do.

In software we may call them euphemisms like "solutions architects" or "devrel engineers", but sales engineers have always existed. They aren't necessarily the frontline of the sales department, but someone has to go onto the customer site and explain to the customer's engineers exactly how their shiny new purchase is going to integrate into their existing systems and workflows...

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.

Sometimes you fight and curse the volkswagen-special VKRC safety circuits.

And sometimes you think what kind of shenanigans might happen and why it might be better to have complex safety interlocks that mate with entire automation cell controls...

A relative of mine works with assembly-line robots at heavy equipment manufacturers. He told me that while they were calibrating a new robot that was used to move axles for industrial mining dump trucks, a miscalculation caused the robot to fling a 800 lb axle through the air like a marching band baton.

Now that I'd pay to see. If that happened where I worked, I would be so tempted to run the program again with my phone camera out. After telling everyone down-range to get lost of course.

Now would I do it? No... definitely not, as long as the demon on my right shoulder was being quiet that day.

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.

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.

The story says he did point it at the ground, but a) it was reflecting off the reflective paint they were aiming at and b) towards the end the laser was badly misaligned.

Not operating in a controlled environment, no curtains to block stray reflections, not ensuring your optic path is stable and clear of obstructions and reflective objects. Doesn’t sound like they had a beam block around for safety, nor did they first use a lower power visible laser to simulate beam path.

These types of lasers are integrated into end customer systems by techs at a factory. They are very simple to setup from the black box level of understanding. All you do is plug in water (blue hose in and red hose for out) since the electrical system is typical a box that simply plugs into the laser head and the wall outlet. The only factor that could affect the output power that's not on the controls would be the water temperature.

“Sales engineer” sounds like one of those positions that would be regularly setting up demos for customers and have access to the equipment and basic operating procedures.

“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”

I think this is all a good illustration of why "Bob" was (supposedly) fired at the end of the story.

A good sales engineer knows a lot about the product within its normal operating envelope, but especially knows a lot about the boundaries of "normal operation". Bob's very first response to "can this thing do a thing [that Bob should know is outside of its normal operations]?" should have been to go ask the kind of engineer who is involved in defining "normal". And either the capability is investigated (and, if plausible, eventually a "safe" demo is put together, and maybe the definition of "normal" is expanded), or its revealed that it won't work, and that's that. In either case, the rest of the situation never happens, provided Bob is actually good at the engineering side of "sales engineer".

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.

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"

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.

The structure of the industry is many small companies that make one specific laser based on the owner's PhD research. These companies cannot have the perfect safety culture simply due to staffing numbers.

It reads like most Funranium Labs posts. Here are some other good ones:

https://www.funraniumlabs.com/2015/04/an-april-fools-caution...

https://www.funraniumlabs.com/2018/09/the-fringes-of-regulat...

It's written in the style of tales from tech support.

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 ridiculous.

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. :)

So while trying to answer another comment on cost, i ran into this:

https://www.sciencedirect.com/science/article/abs/pii/S09240... and https://www.sciencedirect.com/science/article/abs/pii/S00303...

I had thought, reading the article, that maybe this was a relatively new idea, and they were at least trying something relatively new in an insane way.

But no, the latter is from 1999 (so when this event occurred), and there were earlier papers they cite.

Using lasers to do paint stripping of coatings from roadways was well studied even then, and all the risks/rewards carefully laid out.

Not that i expect the sales engineer to have read that, but still.

> "oxygen shroud-gas"

Do they call it MOG instead of MIG? Although it's Chlorinated Rubber, not metal, so maybe it's CROG.

I wonder what happened to literally everyone else present at this situation. That's beyond "Yikes!" territory.

Yes, I also dislike the culture in which this can be called a funny story. Such culture will cause more incidents. Worked in a laser lab for 5 years without incident in a time when eye safety goggles were not used for visible light.

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

Yeah, emotions are a positive factor for a memories forming. Add some emotions to a fact, and it will be remembered better and for longer. Some things are remembered for life without any repetition, and mostly it happens for things that trigger your emotions.

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.

I agree there is more to it than yes/no making a joke of an incident. I associate it with a macho culture in which people do not feel safe to speak up in case of unsafe circumstances. Same for IT security.

If the Germans can joke about it, anyone can.

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

This version of Forklift Driver Klaus is much clearer: https://www.youtube.com/watch?v=TJYOkZz6Dck

> 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.

I worked in a laser lab for a few months early in my career. After the safety training I fear lasers getting near my eyes in situations most people don't care about. I even look away from barcode scanners at grocery stores. Sometimes I wonder about lidar being shot in all directions from those self-driving cars around SF.

There's been at least one sketchy self driving startup that drove their LiDAR hard enough they burnt holes in journalists' camera sensors at CES.

https://arstechnica.com/cars/2019/01/man-says-ces-lidars-las...

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.

Should I be concerned about the lidar in my dreame robot vacuum (L10s ultra) and my 3 years old whose head is closer to the ground than me?

I never thought about it before but you'r comment worries me.

So going by what they aimed for in building the laser: No. The nominal power and wave length of all of these appliances is less harming to the eye than going outside on a sunny day and forgetting your sun glasses.

The issue here I guess are malfunctions or rather cheap products with bad calibration. For total safety you'd have to get someone to measure input and output of the laser.

I'd love to reassure you about something like low input power, but at the end of the day with cheap products you don't know. If a higher powered laser was cheaper at the time of production, the extra milliwatts would probably be negligible compared to overall power consumption of the robot.

So the lidar is unlikely to immediately cause eye damage at a glimpse, but if your kid likes to chase the robot and thus might look into it for longer periods of time, maybe look into options of checking the laser's actual input power.

Keep in mind that LIDAR is moving lasers too, which are allowed to be higher power but should have an interlock that turns the laser off when it stops moving.

I'll leave the extrapolation on how that could go wrong to you.

Hmm my kid does like to chase the robot.

It seems rather difficult to measure the laser input power though. Apart from trying to reverse engineer the robot?

I guess I'll just make sure that it's not turned on if my kid is awake at home.

Wait, are barcode scanners lasers? I've always thought of them as red lamps because their cone spreads out so widely quickly.

Some of them are, some of them aren't. There are obviously laser based ones that are easily recognizable as they produce a pattern of lines instead of a relatively evenly lit field. It's surprisingly difficult to find a picture of that, but I found a video that shows it well[1]. The ones that produce even illumination are probably LED based.

[1] https://www.youtube.com/watch?v=PIn00-qW5WI&t=1m34s

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

The stationary ones used to have a spinning mirror with a laser pointed at it. You used to be able to look in the machine and see it. Dunno how they do it now for the handheld scanners. Smaller mirror or some other trick like piezo?

Hand scanners for a while have been able to use just LEDs to illuminate the barcode it turns out. Way cheaper than having so many moving parts like the older laser based scanners.

That brings back memories. One of my first research projects in school was doing sketchy things with a Quanta-Ray Nd:YAG laser. I remember the distinct 'tack-tack-tack' sound of the Q-switching at 10 Hz which I used to create a laser-induced plasma right around eye level.

Fortunately I had the proper goggles on but was always terrified of catching a stray reflection and blinding myself. Now we live in a world of dirt-cheap high-powered diode lasers, and when I see all the stupid things YouTubers do with them with almost no discussion of proper eye safety, I wince.

One of the important safety lessons that non-experts could take from this story is that protective eyewear for lasers can be highly specific to the kind of laser (as lasers have only a single wavelength, the eyewear may be designed to filter out that specific wavelength rather than attenuate light-in-general). I once knew this but had forgotten it, and some of the people in the story apparently never knew it.

Also the mirror and low-divergence thing are so scary. Much like laser microphones! We have a pretty deep human intuition that other people must be at least somewhat close by in order to harm us, and lasers break that intuition.

I have had lasers in my life a long time and have always appreciated the risks, but I have taken a couple of very brief hits to the eye.

Fortunately, my eye doctor has never seen anything that looks like damage, and aside from extreme nearsightedness totally unrelated to lasers, my eyes work fine.

These ultra-powerful lasers that will toast your retinas instantly scare the shit out of me. The fact that you can buy a tattoo removal gun on AliExpress (https://www.aliexpress.us/item/3256806988159318.html) is just insane. The kinds of mass-violence you could commit with a device like are outrageous, I figure it's only a matter of time before someone uses something like this against an unsuspecting crowd.

Even just using the wrong kinds of lasers or UV lights at a concert can have awful consequences: https://www.theguardian.com/music/2008/jul/16/news.seanmicha... / https://arstechnica.com/health/2023/11/bored-ape-creator-say...

If this kind of thing can happen by accident, imagine what could be done on purpose.

and if you want to see the tattoo gun in action

https://www.youtube.com/watch?v=-BeTq99LqUo

Rule number 1 of laser safety is "do not look into beam with remaining eye".

I think that's rule number two. Right after "don't look at the laser".

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

the other saying I know is: "you can see laser only twice in your life, once with your eye and second time with the remaining one"

When I was a kid, I tried to look at it and nothing happened just like my friends said. All warnings failed to deliver a message that eye damage may be delayed and invisible at first. I didn’t lose sight after 30 years, so that laser was probably safe, but for fucks sake can they write non-dismissable warnings instead?

Reminds me that stupid low bridge warning: “overheight must turn”. Instead of messaging to a driver that they are overheight right now it just reads as a general rule. Numerous incidents per year as a result.

I've touched all sorts of things in my "Maker" years, but one of the things I'm never going to touch by far is lasers. I know how bad they are, and I also know how woeful unqualified I'm for messing with lasers. Heck, I've even left a couple of dancefloors in clubs that I heavily suspected were firing actual lasers at the people, wonder how many of those were actual lasers vs light pointers and how many people got unknowingly injured, but it was just not worth the risk.

> Heck, I've even left a couple of dancefloors in clubs that I heavily suspected were firing actual lasers at the people, wonder how many of those were actual lasers vs light pointers and how many people got unknowingly injured, but it was just not worth the risk.

It is not really clear what you are saying here. What do you mean by "actual lasers" vs "light pointers".

Whether or not a light show is safe has nothing to do with the light source being an "actual laser" or not. What matters is what kind of laser and how it is used.

Last year I went to a karaoke dance floor club thing in NYC k-town and I saw literal burn marks on the wall. A spinning laser disco thing continuously traced across the burn mark. I got our group the hell out of there but they only agreed to leave because it was too loud

They are actual lasers and they're fine. Assuming you're talking about the light shows and not just random people.

I mean the light shows. Why do you say they are fine? It'd depend on who sets it up, right? If it's professionals I'd be a bit less worried, but in my country and many others def-not-professionals handle things that they shouldn't be handling, including setting up official shows.

Are they building homemade laser rigs or something?

They are buying equipment that is supposed to be pointing to the sky and set up by a professional and setting up haphazardously by themselves.

Even better is when the dancefloor wants UV lighting, so they just buy some cheap UV-C bulbs

Funranium has a post about that, too: https://www.funraniumlabs.com/2023/11/ultraviolet-rant/

> We do not want to share space with a UV-C air sterilizer because we like to see with our eyeballs

This was a good read.

https://kotaku.com/bored-apes-nft-blind-eye-pain-uv-light-pa...

most famous example of that.

What are the implications of that choice? Safety?

UV-C light is used for disinfecting, because it's very good at killing biological things

One thing I learnt, different glasses for different type lasers, who knew :)

One of the professors in my uni lab had "universal laser goggles".

They were regular goggles with a sheet of lead bent over them.

Niiice. Even attenuates those xray lasers!

That and different glasses depending on how you use that laser... Because some lasers can do variable wavelength.

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.

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

No, the cameras would probably not survive laser exposure beyond a cat toy pointer level power (and even then I wouldn't bet long exposure of those).

That’s fine. If I worked in a room with a laser and I screwed up and hit my face, frying an Apple Vision Pro seems like a pretty small price to pay. My eyes will be fine.

And the Apple Vision Pro works against tunable lasers, lasers of unknown frequency, flashlamps, etc.

They'd still protect your little human eyes. If you wanted to use them as safety glasses normally you'd want their cameras to be easily replaceable but they would function as safety goggles for short periods until the camera caught a stray beam.

Cameras are cheap, eyes are expensive.

Ok, the Vision pro cameras are probably very expensive (mostly because I doubt you can just switch them with new ones). Maybe put a bag over it and a Pi camera on the outside? Can you live-stream to a Vision Pro?

That's actually not a bad idea. It's just mildly more expensive than your typical goggles.

Why can't there be glasses with the different types layered together into one?

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

You can get some overlap tho. I have 520nm goggles that tone down 465nm.

That's mostly because it's tough to get a perfect notch filter in the visible spectrum but you'd never want to use the 520nm with a 465nm unless it was low enough power the fuzzy edge of the filter knocked it's power down enough to be safe.

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.

"Are you declaring war on the United States, Bob?"

This almost made me spill my tea...

A few years ago I worked in a high rise in an office with a window facing Moffet Airfield. I worried about crashing experimental planes but never thought to worry about being blinded by a stray laser beam. Maybe I'm not paranoid enough.

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).

One of the lessons you can take from this is that people think in the tools they know even when there's better, simpler tools available.

It wouldn't be hard to get some asphalt into the lab, but if you don't know how to pour asphalt...or swing a hammer, you're gonna haul the tool you know to the asphalt

Lasers absolutely terrify me now; I impulse bought a 2w lasercube in 2020 for next to nothing (circa $200) and once I started reading up on it I was pretty appalled how easy it was to buy.

This was a fairly expensive RRP laser with some level of protection and stuff around it, the fact you could buy pens capable of pretty significant damage on ebay for way less where people wouldn't even grasp just how dangerous the thing is.

So I've got a laser I'm afraid to play with until I can make a safe environment for it and I'm even more afraid to sell on to anyone...

Feel like there's going to be some atrocity and some big time laser panic in the future.

Why not just wear the appropriate goggles? You don't have to be afraid, you just have to be careful.

Of course, being careful means considering the possible presence of subharmonics, and buying your goggles from legitimate suppliers rather than unpronounceable Chinese brands on Amazon or eBay.

I will when I have appropriate goggles; it looks like they'd cost not too far off what I paid for the laser itself though?

Not to be insensitive about your injury, but I'm more curious how you got your laser eye.

What a wonderful story about why we can't have nice things. Hopefully nobody else outside of the story was hurt.

Lasers are fun. Like all fun things, they demand respect.

That is a heck of a cocktail story. A bit more terrifying than I expected. As the safety officer, I wonder what new policies they put into place after this.

“Do not let salesweasels anywhere near the bright shiny things” hopefully.

> On closer inspection, we later leaned that the Quanta-Ray had burnt through the wheel well and cut the brake line.

The I guess they were lucky that they weren't aiming in the general direction of the fuel tank, or that the "experiment" was stopped before burning through it?

Having started out my tech career as an intern in an industrial laser lab, this story is parts amusing and horrifying. Brought back a lot of memories of all the ablation tests and via drilling I used to do, with varying degrees of success, to help sell this massive lasers.

I went to a talk by a guy who worked on fibre lasers. Shortly after he showed a video demonstrating how it would work its way through a brick wall in about 20 seconds, he suggested that they might one day be commercialised by selling them as tools for people to slice up tree branches in their backyard, seemingly without any awareness of how terrifying a prospect this is.

One of my favorite sites, was the US Navy Safety Picture Of The Day site.

It was crazy, how bad we can get.

I think the site has long been retired.

You are probably thinking of this -- long gone, but still archived thanks to the Wayback Machine: http://web.archive.org/web/20081019180813/http://safetycente...

Yup. That's it!

Thanks!

Are there any stats on the scale of laser eye injuries?

Like what percentage of the world population are blind because of laser injuries? What percentage have permanent vision issues?

How do those compare with the number of people who work with lasers?

How does it compare with say vision loss from arc welding?

it's hard to know if you have eye damage, we have big blind spots right in the center of our eyes that we are not aware of.

our brain can fill out missing data from context and the same happens with eye damage.

with progressing damage you will see normally until you cross some threshold where your brain gives up and you are then blind

One of my cleverest friends loves to say, “do not look into laser with remaining eye.”

Missed an opportunity for the Family Guy "use the force" scene: https://www.youtube.com/watch?v=8ynXqTLKHhU

> the company claims the machine can take care of business safely "even in the most movement-heavy conditions," and that dry run testing on moving humans has all been successful.

So many questions

Didn't anyone ever tell you to make sure your optics are clean?

-Kent

Blame Free Retrospective challenge

1999, when you could pull a stunt like this and still get two weeks notice for it

Just for giggles, who owned Spectra-Physics at the time?

You could have just said "Sales Guy"

how do people like Bob get a job in the first place?

- Familiar enough with product to set up customer demonstration on his own with minimal help from enigneering

- Shows initiative by exploring novel applications with customers

- Expertly alleviates doubts & hesitation in customers

:P

Honestly, apart from blatant disregard for safety culture, that is not a bad salesperson at all.

Without additional info, I would honestly put the blame mostly on the company, because instilling a certain respect for dangerous products should be part of company culture and employee training, you just can't expect fresh hires to come with all the common sense baked in...

not really related, but people say you shouldn't look directly at the sun.

I don't understand why having the sun in your field of view at all isn't dangerous then. wouldn't that cause the sun to burn a hole somewhere inside your eyeball that isn't the direct center?

Moral of the story is: make sure and tag the safety officer when you’re being stupid so he can make sure and inform all of the correct people.

[flagged]

This was a great read, thanks for sharing!

The laser should've been mounted on a shark.

"Sharknado 8 - Now They Have Lasers!"

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