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Picking a Laser Hack Chat

The light tool for the job

Wednesday, February 22, 2023 12:00 pm PST Local time zone:
Hack Chat
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Jonathan Schwartz will host the Hack Chat on Wednesday, February 22 at noon Pacific.

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You've got to admit that it's a pretty cool world to live in that presents a problem like, "Which laser cutter should I buy?" It wasn't all that long ago that decisions on laser purchases were strictly in the realm of Big Science, and the decision was driven as much by spending grant money as by the specifics of the application. If you were in need of a laser back then, chances are good you had some deep pockets, or at least access to someone else's pockets.

Fast forward a couple of decades or so and buying a laser is an entirely different exercise. Lasers have become a commodity, and finding the right one depends entirely on your use cases. Lasers are no longer jealously guarded laboratory instruments, but workhorses on the vanguard of the desktop manufacturing revolution. They engrave, they cut, they melt -- in short, they do a LOT of work. And it's up to you to choose the right laser for the job.

To help us sort all this out and come up with a plan for figuring out the best laser for any use case, we've invited Jonathan Schwartz back on the Hack Chat. Jon dropped by back in March of 2021 to share his wealth of laser experience thanks to his laser-cutting business. This time around we're going to focus -- err, concentrate -- oops, drill down -- oh, whatever! -- on the more practical aspects of buying a laser. We'll talk about laser types, fiber lasers, applications vs. laser specs -- anything you can think of. If you have questions about buying a laser, we'll have answers!

  • Hack Chat Transcript, Part 2

    Dan Maloney02/22/2023 at 22:06 0 comments


    charliex1:01 PM
    i vent ours outside , since it has a lot of contaminants in it

    Thomas Shaddack1:02 PM
    Probably with some filler in the rubber.

    charliex1:02 PM
    co2, fibre, all of them outside you can do it into an active carbon filter as well to help, but its a lot of gas and very small particulate

    Thomas Shaddack1:02 PM
    would bubbling through water do the job instead of a filter?

    Dan Maloney1:03 PM
    World's worst hookah

    charliex1:04 PM
    it'd need a lot of flow, but maybe, waterjets do use the water to help with that too, so its feasible, but there is still the gas depending on what you're cutting

    Dan Maloney1:04 PM
    Hey @Jonathan Schwartz - we're past an hour now. Want to keep going or wrap it up?

    Thomas Shaddack1:05 PM
    Aliexpress has some sweet-looking "80 watt" 450nm lasers. How much should I trust the offer? (Assuming incoming power instead of optical.)

    Thomas Shaddack1:06 PM
    they are reportedly combining power from two diodes.

    Thomas Shaddack1:06 PM
    it may have multiple chips and beam combining in-module.

    Thomas Shaddack1:08 PM
    I had good experiences with thin white material cutting when the line was dyed yellow.

    Jonathan1:08 PM
    Thank you!

    charliex1:08 PM
    makes a lot more sense when you're watching the youtube too heh

    Thomas Shaddack1:08 PM
    another trick, engraving polyolefins. paint the engraving areas (text) with a black pen, then scan with defocused blue laser.

    Thomas Shaddack1:08 PM
    translucent material ignores the beam, paint heats and bakes into surface.

    Thomas Shaddack1:09 PM
    TRICKS! Do tell do tell do tell!!!

    Thomas Shaddack1:09 PM
    the trick was to make sure text on polypropylene bottles of solvents won't wash off.

    Thomas Shaddack1:11 PM
    Any interesting fails? My one was trying to use nascent iodine generated from laser decomposition of iodoform, to etch copper on circuitboards. The copper totally ignored the process and everything stank like an old hospital for DAYS.

    charliex1:12 PM
    colour is interesting, we managed once to make repeatable colour with our mopa but never again.

    Thomas Shaddack1:13 PM
    logical. focal point on surface vs in the middle of the material thickness.

    charliex1:13 PM
    its very sensitive to temperature

    Thomas Shaddack1:13 PM
    thought. selective surface melting. coat a surface with a powder, eg. plastic or solder, and then raster/trace over.

    charliex1:13 PM
    which is a big issue with fibres and metal, the work area heats up and changes the cut properties. so much easier with co2 wood/plastic

    Thomas Shaddack1:14 PM
    then brush off the unmelted powder.

    Thomas Shaddack1:17 PM
    you can also engrave atypical stuff. I had success with sugar candy.

    charliex1:18 PM

    charliex1:18 PM
    i like making keychains :)

    Thomas Shaddack1:18 PM
    what about a 5-axis head for the laser? engraving non-flat objects?

    charliex1:19 PM
    carbon steel

    charliex1:19 PM
    yes

    charliex1:19 PM
    3/16th

    charliex1:19 PM
    in the garage

    charliex1:19 PM
    LA

    charliex1:19 PM
    sure , i'm in northridge

    Nicolas Tremblay left  the room.1:19 PM

    Thomas Shaddack1:19 PM
    that's a SWEET machine!

    Thomas Shaddack1:20 PM

    https://www.improwis.com/projects/food_LaserEngravedCandy/

    IMPROWIS

    Laser engraved candy

    Because, why not? Does everything need a justification? This was the inspiration: Bittersweets, the despair.com Valentine candies A 40W CO2 K40-III laser cutter was employed. A test image ("test" text) was used for the engraving. The candy used are the kind consisting of pressed sugar, with some added starch, citric acid, flavorings and dyes.

    Read this on Improwis

    charliex1:21 PM
    1kW fibre

    Thomas Shaddack1:21 PM
    could it be done via 3d-scanning the object, then autogenerating the paths of the 5-axis thing to deliver beam perpendicularly to the object where desired?

    charliex1:21 PM
    sure, we are usually hanging out saturdays and doing stuff

    Thomas Shaddack1:22 PM
    g-code is the easy part. gcode is nothing but positions of the machine. a bit of math. brain-melting math at times but still just math.

    charliex1:22 PM...

    Read more »

  • Hack Chat Transcript, Part 1

    Dan Maloney02/22/2023 at 22:05 0 comments

    Jonathan Schwartz11:54 AM
    I'm here if you guys want to ask a couple questions before we start.

    Dan Maloney11:54 AM
    Hi Jon! Welcome back!

    Jonathan Schwartz11:54 AM
    Thanks Dan

    anfractuosity11:54 AM
    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?).

    Nicolas Tremblay joined  the room.11:55 AM

    Jonathan Schwartz11:56 AM
    What do you need it for? There are lots of options if you dont need the best one on the market

    anfractuosity11:56 AM
    It's basically to create laser speckle to replicate this -

    I doubt I need anything too fancy

    Jonathan Schwartz11:57 AM
    Amazon has a lot of Chinese lasers that are really good.

    Jonathan Schwartz11:57 AM
    and the glasses

    anfractuosity11:57 AM
    Cool, and the glasses would protect against IR?

    Jonathan Schwartz11:57 AM
    they are generaly considered 90% effective at blocking but that would be a direct hit which does not happen almost ever

    anfractuosity11:58 AM
    ah cool

    anfractuosity11:58 AM
    I was a bit wary of amazon/aliexpress as i thougt the power of laser might be incorrect?

    Jonathan Schwartz11:58 AM
    they can be

    Jonathan Schwartz11:58 AM
    but normally it is advertised as more power. let me explain on vid.

    anfractuosity11:59 AM
    okey doke, thanks

    Dan Maloney11:59 AM
    @Jonathan Schwartz - the YT vid says the stream will start in an hour, just FYI

    Dan Maloney12:00 PM
    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

    Jonathan Schwartz12:00 PM
    I am live

    Dusan Petrovic12:01 PM
    Hi Dan, Jonathan

    Jonathan Schwartz12:01 PM
    hey

    Dusan Petrovic12:01 PM
    welcome everyone!

    Dan Maloney12:01 PM
    Also, there's a simulcast livestream over at

    Jonathan Schwartz12:02 PM
    I will answer questions from here on the vid

    Dan Maloney12:02 PM
    While we're waiting, Jon, can you give us a little about how you got started in the laser business?

    Jonathan Schwartz12:03 PM
    I will answer on the vid

    Dan Maloney12:05 PM
    Everyone make sure you jump into the YT vid too -- Jon's answering questions over there.

    Dan Maloney12:06 PM

    https://www.youtube.com/watch?v=qcX5F3n68RM

    YOUTUBE AMERICAN LASER

    Matteo Borri12:08 PM
    Hi there, spiritplumber (person who makes the L-Cheapo laser)

    Dan Maloney12:09 PM
    Hi @Matteo Borri !

    Matteo Borri12:09 PM
    we're still making the l-cheapo mk7 so if anyone has a question on diode lasers I can try to help :)

    Matteo Borri12:09 PM
    we also put the pcb's on the wiki so if people want to make their own, go right ahead.

    Jerry Isdale12:10 PM
    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.

    Matteo Borri12:10 PM
    14 years is a pretty awesome service life

    Matteo Borri12:10 PM
    how are you cooling it?

    ben.phenoptix12:12 PM
    Howdy all, I've owned all manner of cheap laser cutters, and have run them for kit businesses. The latest one was the trickiest

    Nicolas Tremblay12:12 PM
    Can you give us an idea of optical laser power vs cutting/engraving capability

    Dan Maloney12:12 PM
    Newcomers -- don't...

    Read more »

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