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On 11/24/2019 at 3:56 AM, Craig Sawyers said:

Particularly as he was totally unaware that these small diode lasers produce enough power to cause real damage.

Are you suggesting that this isn't a great idea? That Amazon would sell something unsafe? Shocking! It comes with safety glasses.

Also worth mentioning that you need a good ventilation and filter system with these things. The usual course of laser cutting emits some nasty smoke and whatnot, but some materials (PVC, ABS, etc.) can emit chlorine, cyanide, etc. when cut.

Edited by dsavitsk

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Also worth noting you can just buy a 5.5W laser module for less than UKP100 https://www.amazon.co.uk/Engraving-Control-Adjustable-Focusable-Engraver/dp/B07VW9YSSQ/ref=sr_1_49?crid=ACLL7JBCVN4C&keywords=diode+laser&qid=1574845348&sprefix=diode+las%2Caps%2C137&sr=8-49

You get a pair of googles thrown in. 'triffic.

Back in the day when such lasers occupied a fair sized lab and cost a fortune, we were required to attend a laser safety course before we were let loose. That was sufficiently long ago that you could show live monkeys being subjected to laser light into their eyes. At least it pushed home the point that a high power laser was not something to be treated lightly. There was also a guy who said "I served in Vietnam. And nothing prepared me for viewing the world through my blood filled eyeball"

We wore goggles every day. Fully sealed around the eye. They were hot and inconvenient - but so is a hole in the retina. And 5W is sufficient to boil whatever humour is closest to the retina before you can blink. The doors were all interlocked, with a light on outside. If the door was opened, the laser power supply shut down, and a shutter closed as a fail safe.

Now you can buy such a laser for pocket money and hold it in your hand. So there is a complete decouple between the physical thing, and what it can do.

Edited by Craig Sawyers

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Always want to get a laser engraver/cutter for my Stepcraft CNC rig.  This seems to be a good idea.   But don't know how turn the laser on (or off), via g-code?   

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8 hours ago, Craig Sawyers said:

Also worth noting you can just buy a 5.5W laser module for less than UKP100 https://www.amazon.co.uk/Engraving-Control-Adjustable-Focusable-Engraver/dp/B07VW9YSSQ/ref=sr_1_49?crid=ACLL7JBCVN4C&keywords=diode+laser&qid=1574845348&sprefix=diode+las%2Caps%2C137&sr=8-49

You get a pair of googles thrown in. 'triffic.

Back in the day when such lasers occupied a fair sized lab and cost a fortune, we were required to attend a laser safety course before we were let loose. That was sufficiently long ago that you could show live monkeys being subjected to laser light into their eyes. At least it pushed home the point that a high power laser was not something to be treated lightly. There was also a guy who said "I served in Vietnam. And nothing prepared me for viewing the world through my blood filled eyeball"

We wore goggles every day. Fully sealed around the eye. They were hot and inconvenient - but so is a hole in the retina. And 5W is sufficient to boil whatever humour is closest to the retina before you can blink. The doors were all interlocked, with a light on outside. If the door was opened, the laser power supply shut down, and a shutter closed as a fail safe.

Now you can buy such a laser for pocket money and hold it in your hand. So there is a complete decouple between the physical thing, and what it can do.

Same here when I worked as a tech for a semiconductor manuf. probe floor. We had Teradyna and ESI lasers which would do repairs to memory chips (blowing links to remove and patch in redundant cells). All of the laser bays had interlocked doors with lights outside when we were doing maintenance on them. Opening a door would cut power to the laser. Goggles required. Also had my retinas photographed, which was a good time. Don't fuck around with these as Craig mentioned.

Edited by Pars

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Interesting, I used to sell ESI lasers back in the day. Actually, it was New Wave Research which ESI acquired.  

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I'd forgotten about the retina examination - thanks for reminding me. They put drops in to open the iris wide open. So when you walked away you could focus on absolutely nothing for the best part of an hour, and everything was super bright.

Found another one on Amazon - 20W (!!!) at 450nm for UKP122 including the power supply. And this one did not even come with free goggles.

Anything more than 500mW is a Class 4 laser - the highest and most hazardous class. So that 20W unit is deep into Class 4. The flash blindness (ie long afterimages even at the 1/4 second blink reflex) distance is >10 miles from this 20W laser. It is extremely irresponsible for Amazon to sell these things at all, let alone for pocket money.

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I would also point out that some, mostly the type that engrave metals, of lasers do not trigger a blink response because they are in the deeper bands of IR. So all you will notice is your sudden lack of depth perception, or vision at all. I found this horrifying quote from Wikipedia:

"A pop or click noise emanating from the eyeball may be the only indication that retinal damage has occurred i.e. the retina was heated to over 100 °C resulting in localized explosive boiling accompanied by the immediate creation of a permanent blind spot."

And seriously, a $300 pair of safety goggles can cover a wide swath of potential lasers, chump change to the several thousand most of the good machines cost.

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