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A tiny ultrabright laser that can melt steel

spectrum.ieee.org

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Re: A tiny ultrabright laser that can melt steel

#71

Post by GuB-42 »

llm_trw wrote: post #39
aqme28 wrote: post #28

Earlier quoted context omitted.

Those can’t blind you from a distance though. Not nearly the same risk

They absolutely can. Anyone around them for long enough has dead spots in their eyes.

Not at all the same risk profile. Arc welding is just a really bright UV light, and without appropriate protection, it will cause what is essentially a sunburn on the surface of the eye. It is painful, but it usually heals in a couple of days. It shouldn't significantly damage the retina.

Laser light is different: a laser is effectively a point light source, and it will focus inside the eye to a single point with enough brightness to cause a burn. It can cause a permanent blind spot, and damage may happen faster and be less noticeable at first.

Re: A tiny ultrabright laser that can melt steel

#72

Post by stavros »

mecsred wrote: post #68
stavros wrote: post #57

Earlier quoted context omitted.

A question I've always had: How do I know if my glasses protect against a particular laser? I'm talking about the ones in hobby CNC machines, laser hair removal places, etc, not high-powered industrial ones, where there's likely a high degree of know-how on safety already?

Best bet is to buy two pairs and stick one in the path of the beam with a sensor or target behind it. Otherwise you're looking up charts for the materials spectral absorption in your lasers emission band

But even if the target isn't cut, that doesn't mean I won't get eye damage, does it? Or do glasses protect even if they're only a bit opaque to the target wavelength?

Re: A tiny ultrabright laser that can melt steel

#73

Post by BurningFrog »

sarchertech wrote: post #17
aqme28 wrote: post #7

A society in which "the average car-buyer" has a tiny portable steel-melting laser is a society where I'm wearing welding goggles every time I leave the house. And I'm not sure how you even lock a bike or a door or a safe any more.

There are already so many ways to defeat locks, that locks are just there to keep honest people honest and to slow down criminals. The laser in the article took 30 seconds to cut a a tiny disc out of a sheet of steel 100 micrometers thick. That isn’t going to change things on the theft front. There are much more effective methods available today.

Once my bicycle was such a piece of crap that someone stole the lock and left the bike.

Re: A tiny ultrabright laser that can melt steel

#74

Post by sungho_ »

RecycledEle wrote: post #18
aqme28 wrote: post #7

A society in which "the average car-buyer" has a tiny portable steel-melting laser is a society where I'm wearing welding goggles every time I leave the house. And I'm not sure how you even lock a bike or a door or a safe any more.

The same can be said of BB guns that can put out eyes, lock picks that can open locked doors, and bolt cutters than can break chains. More powerful tools are a good thing.

What about nuclear weapons, which have become so accessible that even small organizations can have them?

Re: A tiny ultrabright laser that can melt steel

#75

Post by ChrisMarshallNY »

bloggie wrote: post #9
pureheartlover wrote: post #3

Earlier quoted context omitted.

Honestly I'm kinda surprised there aren't handheld laser engraving devices made for quick and permanent graffiti.

These do exist, here's one I saw recently: https://www.laserpwr.net/hand-held-laser/hand-held-laser-2.h...

30W? That's a pretty powerful laser. A 1W laser can set stuff on fire. A 5W laser can cut steel.

Re: A tiny ultrabright laser that can melt steel

#76

Post by mecsred »

stavros wrote: post #72
mecsred wrote: post #68

Earlier quoted context omitted.

Best bet is to buy two pairs and stick one in the path of the beam with a sensor or target behind it. Otherwise you're looking up charts for the materials spectral absorption in your lasers emission band

But even if the target isn't cut, that doesn't mean I won't get eye damage, does it? Or do glasses protect even if they're only a bit opaque to the target wavelength?

First of all, I take no responsibility for your safety, I'm just some person on a forum.

That being said, it's all a function of how much light enters your eye. You can look up the exposure limits of the human retina for different frequencies of light to get an idea how little is actually required to damage your eye. The target or sensor should be sensitive enough to react to that much incident light. Just putting something behind the glasses and have it not get cut is definitely not enough to indicate no eye damage.

Re: A tiny ultrabright laser that can melt steel

#77

Post by dghlsakjg »

83 wrote: post #37
mft_ wrote: post #24

Earlier quoted context omitted.

CNC would be an obvious implementation. At the moment, there are expensive-but-affordable home CNC laser cutters, typically for a small number of thousand EUR/USD. The more powerful ones can do a very neat job cutting (up to a few mm of) plywood. There are also CNC plasma cutters, which do a good but slightly rough job of cutting sheet metal, and are relatuvely large and complex beasts. I guess a highly-powerful lase…

Diode based lasers have driven the cost to laser cut plywood down to affordable levels (~$200 for a creality/comgrow/chinabrand 5w laser). I just bought two of them off ebay as "customer returned" for $75 dollars a piece. they work great on the 1/8in plywood and 3/8in foam i've been cutting. Haven't tried 1/4in ply yet but I bet going slower or multi pass and it will do it. Edit: It easily cut 1/4 ply (used 2 passes,…

What is this genre of machine called, just a laser cutter? I would love to play with this

Re: A tiny ultrabright laser that can melt steel

#78

Post by Propelloni »

devoutsalsa wrote: post #56
Thorrez wrote: post #38

Earlier quoted context omitted.

Does the Netherlands have a law against knowingly buying stolen property?

Every place in the world does probably. But how would you prove an unmarked, cheap bike was stolen?

You wouldn't but nowadays no bike is unmarked, even the cheap ones.

Re: A tiny ultrabright laser that can melt steel

#79

Post by Swizec »

Thorrez wrote: post #38
lucioperca wrote: post #22

Earlier quoted context omitted.

A dutch women told me once a story, where she but a used bike in Amsterdam and the heroin addict who sold it to her, threaten her to steal it again, if she does not use a heavy lock.

Does the Netherlands have a law against knowingly buying stolen property?

The Netherlands famously has more bicycle thefts per year than citizens. At this point you could almost think of cheap commuter bikes as public property.

People in countries where bicycling is not seen as a personality statement generally ride very cheap city bikes around town. Last time I bought one of those in college it cost about 30eur. Is not like in SF where people ride 3000 dollar bikes to work because omg you’re a cyclist now and this is your whole identity.

Re: A tiny ultrabright laser that can melt steel

#80

Post by ben_w »

notyoutube wrote: post #48
passwordoops wrote: post #25

Earlier quoted context omitted.

When I moved to the Netherlands my boss told me to never spend more than 20 euro on a bike because it will get stolen. I didn't listen, and lo and behold two weeks in my 75 euro bike and the 35 euro heavy duty lock disappeared

I'm skeptical: * Where do you buy a ≤20 euro bike? * Most people on the street have bikes that look to be at least 200 euros new, from what I can tell.

Last time I bought a bike for £20 even second-hand, the Euro had not yet been introduced.

Even in 2011, when I made the mistake of spending £90 for a new bike… well, the pedals came off while riding it due to metal fatigue.

Adjusting for inflation*, I'd expect similar build quality from a bike that "only" cost €200 today.

* hard to do when there is also a currency switch, especially when the exchange rate has changed so much

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