Dan MaloneyI'm here if you guys want to ask a couple questions before we start.
Hi Jon! Welcome back!
Thanks Dan
Hey :), I've got a rather longish question - I'm looking at getting an 830nm laser @ 30mW for an experiment I'm trying to replicate, I was looking at some on here - https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1487
but they're only 3mW, I'm wondering if you have any recommendations for sites to look at. I was also wondering, can you get laser goggles that protect against IR, and up to what power laser can they protect against (I wasn't sure also if they can protect your eyes if you directly accidentally look at the beam? I assume maybe not?). I'm also looking for a 20x beam expander for the IR laser (in order to create laser speckle), but the ones on thorlabs are very expensive (I assume I can't use a microscope objective, which i have used with a red laser as that would be glass?).
What do you need it for? There are lots of options if you dont need the best one on the market
It's basically to create laser speckle to replicate this -
Amazon has a lot of Chinese lasers that are really good.
and the glasses
Cool, and the glasses would protect against IR?
they are generaly considered 90% effective at blocking but that would be a direct hit which does not happen almost ever
ah cool
I was a bit wary of amazon/aliexpress as i thougt the power of laser might be incorrect?
they can be
but normally it is advertised as more power. let me explain on vid.
okey doke, thanks
@Jonathan Schwartz - the YT vid says the stream will start in an hour, just FYI
Hi folks, we're going to get started now. I'm Dan, I'll be moderating today along with Dusan as we welcome Jonathan Schwartz back to the Hack Chat. Last time we did a "Lasers 101" chat, and today we're going to talk more about the nuts and bolts of buying a laser cutter/engraver
I am live
Hi Dan, Jonathan
hey
welcome everyone!
Also, there's a simulcast livestream over at
I will answer questions from here on the vid
While we're waiting, Jon, can you give us a little about how you got started in the laser business?
I will answer on the vid
Everyone make sure you jump into the YT vid too -- Jon's answering questions over there.
https://www.youtube.com/watch?v=qcX5F3n68RM
Hi there, spiritplumber (person who makes the L-Cheapo laser)
Hi @Matteo Borri !
we're still making the l-cheapo mk7 so if anyone has a question on diode lasers I can try to help :)
we also put the pcb's on the wiki so if people want to make their own, go right ahead.
aloha! I have a Epilog Helix that is now about 14yo. I do not run a biz with it, mostly used for hobby work for a while but havent used much in last few years. It has Issues running long times.
14 years is a pretty awesome service life
how are you cooling it?
Howdy all, I've owned all manner of cheap laser cutters, and have run them for kit businesses. The latest one was the trickiest
Can you give us an idea of optical laser power vs cutting/engraving capability
Newcomers -- don't forget to tune into the live stream too:
That's where Jon is going into depth on answers
14y but 3rd tube and many many months sitting unused
"Buy once, cry once", right?
Chris in South Korea here, I *finally* woke up early enough to join a Hack Chat
hello fellow photon wranglers
@Jonathan Schwartz - if I can take it back even further: How do you decide if you even need to buy a laser? As opposed to, say, a plasma cutter or a waterjet. Off the top of my head, if you're looking to build a business around metal cutting, seems like the money you'd need to get a fiber laser might make non-laser alternatives attractive.
100-120watts? thats pretty powerful. using 40-60w was fine for most acrylic and wood i did.
if i was going todo thick stuff i would definitely look at plasma or waterjet. especially for metal
the finish on the fiber is nicer than a plasma, lots of mess with a plasma too
plasma is cheaper though, and needs less consumables so there is that
Higher power lasers DEFINITELY need the protective case. The protective glass is also very important. If you cut anything even slightly reflective, the laser light can bounce out of the enclosure and possibly damage eyes.
Wood enclosure? yikes. I've had enough issues with wood target catching fire. a wood enclosure is asking for a spectacular fire.
I'm thinking of the use case where you're trying to build a business around cutting. I know a guy who worked for a metal supplier and he says the number of people that come in asking for a quick part to be cut out of sheet steel could build a tidy little business
theyre getting cheap enough now you can have a metal cutting fibre at home, i have one in the garage
Hmmm...
its only 1kW so cuts like upto 10mm carbon steel, maybe 5mm alu or so
fume extraction - very important, but be aware the air flow over wood cuts can fan embers to keep them glowing - and eatting the material!
you just need more stuff than you do with a co2 or a low wattage fibre , like a galvo 60w type which just mostly engraves
could a nitrogen generator be used for the gas instead of air? or oxygen for steel cutting?
and ALWAYS stay near the laser when running, and dont get too distracted. it only takes a few moments for a fire to get started and really mess up your machine
thought. fire detector via opencv. the visual signature of a well-going cut will be much different than a thing burning uncontrolled. can either run the alarm or co2-blanket the workspace.
Wait how cheap were you able to get a 1kw laser for
And the 10mm steel needs gas assist I assume
would wood enclosure with fire-resistant (intumescent for example?) paint/coating mitigate the fire risk?
pretty much all fibre cutting needs gas assist, either 02 or nitrogen
you can pick up a metal cutting fibre for about 18K USD
wood is not necessarily uniform. Some species are uniform (baltic birch) but others are horribly non-uniform (eg Koa). It depends on the density and type of grain. More colorful, variable grain is also likely more variable in density.
Things are getting cheap in the fiber market then, I guess
and it uses a lot of n2, so you'll be getting 300 tanks all day long, i just bought a rotary screw compressor with a dryer , which hopefully means i can replace the n2
yeah i bought ours a few years ago, they're pretty cheap
for >1kW you'll likely need three phase
Even fire retardant wood seems like a bad idea with such a strong laser
That could be a problem in a residential setting. Rotary converter, maybe
that's interesting re. needing 3 phase, what's the input power for a 1kW machine?
@charliex thats pretty expensive for a hobby/makerspace but if you are gonna make a biz, then 18+k isnt too bad an investment. Of course all the additional costs drive that up - power, fumes, consumables (gas)
it's cheap for a machine that can cut metal cleanly
thought. an electric car battery to provide the high power for the machine for the time when it runs, as long as it averages to below what the mains can give over the day.
compared to a waterjet for instance, plus all the stuff you'd need for support for a waterjet, which you're very unlikely to get at home cept for something very very basic like a wazer
^Water jet sand is stupid expensive
the 1kW i run off a 50A 220VAC,
i have a rotary converter for 3phase, they're cheap and easy enough nowadays
a suitable compressor is gonna be at least 15HP if you aren't using cylinders for the n2, i really hope it solves it, but waiting for it to arrive
...after world war 3 there will be enough discarded milspec antidrone antimissile highpower cw lasers...
Another reminder for latecomers - make sure you're in the live stream too:
ahh is that why its quiet in here:)
It pays to be paranoid, I guess
Hi, while browsing hackaday I came across this chat and I have a few laser related questions in my current project. I'm trying to build a homodyne laser interferometer using a cheap laser diode. I did read a bit about the topic on Sam's Laser FAQ, but since he uses HeNe lasers, I'm a bit lost to what I exactly need to look in a laser diode to replace it. For its usage, I would use it for machine calibration (I know it's just a bit overkill for the intended purpose) and maybe CMM in the future when I learn a bit more. I would like it to be able to measure distances up to 1 meter, maybe 2, but precision wise, if its remotely better than a micron I would be more than happy with it. Thank you in advance for your help.
laser diodes are pretty lousy, beam quality wise. maybe sufficient. green 532nm frequency-doubled Nd:YAG could be better for similarly low price.
@Tin Lerinc - Jonathan may have some insights on this, but we're concentrating on laser cutters and engravers. But I bet I know someone who can help you -- Les Wright. He's into all sorts of laser projects like that.
If you like, I can give him you info and maybe he can reach out to you
@Jonathan Schwartz - sounds like filling tanks for welding. It's gotten really expensive
I've bought an optical table with an interferometer setup on, but only tried a red laser diode so far with it, and haven't been able to see the interference patterns yet, not sure why though :(
(mine is a Michelson interferometer)
i can run thru a 300 sized n2 tank in about 15 minutes
which i think its about 60-80$ refill
and also a trip to physical therapy after moving a few of those tanks, o2 lasts for ever since you hardly use any at these levels. and oddly enough a lot of gas companies don't want to do residential deliveries :)
@Dan Maloney If you can, sure, I would like to learn more if possible.
random thought, for the stink, could the volatiles be degraded by eg. a low temperature plasma?
what about laser welding, or even laser brazing/soldering?
@Jonathan Schwartz Thank you anyways for your answer.
a K40-III "Blue Horror" class machine is a nice thing to have. replace the electronics to run with g-code. The discharge tubes take some current to light up, and the low-power end is unreliable and won't go all the way to zero. this can be worked around by switching the beam, going pixel by pixel and delivering a measured number of microseconds at reliably-enough power.
what problems? do tell! my one runs ancient patched Marlin, with lots of my tweaks.
(Technically raspi is a computer too.) I run it as an ATmega2560 board with Marlin, slaved to raspberry pi running octoprint.
https://www.youtube.com/shorts/EQerPa7Ee9s
laser time, fibre 3/16th steel
I am thinking of buying my first laser cutter. On the exhaust system: Do I need to exhaust directly outside or can I feed that exhaust into my building's HVAC return?
Cough cough cough!!!!
sparks a flyin'
You've got to consider make-up air too. If you're sucking the volume of the shop out every, say, five minutes, you've got to provide at least that much air from outside
Also, I had issues with some rubber sheet. When cutting gaskets it generated weird campfire-like sparks long lived enough to survive the travel all the way out through the blue hose out of the window. Replaced t
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