Gas Containment For Laser Cutters

Tired of breathing all the noxious fumes your laser cutter puts out? Yeah… we don’t have a laser cutter either. But [Jeri Ellsworth] does and she needed a way to evacuate off-gases generated during cutting so that they don’t damage the laser cutter, or her lungs. What she came up with is a containment box that attaches to a pump system.

The problem is that you want to keep the gases away from the laser cutter hardware but you still need to be able to shoot the laser at your work material. Her clever solution is to use a silicone wafer like the ones with which she makes integrated circuits. They allow the infrared laser to pass through without being chopped in half. What you see in the image above is a red box with the round wafer in the center. Near the bottom of the image is a clear window so you can see what’s going on with your work piece. But to get the full idea you need to watch the video embedded after the break.

We can’t help but think she’s building this in preparation for some more chemistry hacking.


27 thoughts on “Gas Containment For Laser Cutters

  1. Cool trick using the silicon wafer… but… can’t you just stick a computer fan on one end of the cutter and an air opening at the other side of the “printing” area space? Run a small pipe into a nearby window and you’re done.

    PS… I don’t have a laser cutter :( lol

  2. neat idea, especially for cutting things like PVC where the corrosive gases from cutting will actually destroy your steering lens. Not that useful for most other cuts unless you just really don’t like the smell of burning wood :P

    Also, it’s “silicon”. Silicon is the mineral, silicone is the rubbery compound. Pet peeve of mine.

  3. @juan cubillo: most of the commercial laser cutters you can buy already have a system like that — they have an air injector right at the focal point, and a powerful evacuation system in the whole cutting bed. That’s enough for most materials like acrylic or wood or cardboard, where the fumes aren’t too nasty. Other materials, like PVC, produce corrosive gases and can’t be safely cut even with a ventilation system. So a shield like this would be great.

    Also, you have to clean soot and gunk off your steering lens every so often no matter what you’re cutting, so this prevents that…but then you have to clean the silicon wafer, so it’s not much less work :P

  4. Why not build a box around the entire laser cutter with a vent? You could use acrylic or a thick plastic bag with a zipper if cost is a factor.

    The tin she uses can’t be good for leveling your material. Also, the silicone wafer could reduce the laser’s accuracy if it is dirty, or worse, it could cause stray IR light reflections that you may not be expecting. I personally would not put anything in the path of the laser that I don’t intend to absorb the energy.

  5. I don’t have a laser cutter nor am I a laser expert. But shouldn’t the silicon window be either anti-reflection coated, or mounted at Brewster’s angle to avoid reflecting part of the beam?

  6. To those wondering why Jeri doesn’t just vent the whole thing, in fact she does have a ventilation system for the laser cutter.

    The thing is some things you cut can damage, with fumes, the parts inside the cutter, like the lens that reflects the laser light down into the cut area. So this will prevent those fumes from getting into any spaces that might affect the cutter itself.

  7. Jeri,

    If you’re gonna play with recreating the history of solid state computing, stop mucking about with lasers (waaaaaaaayyy too crude), buy an old electron microscope and start fabbing something besides high capacitance FET mockups.

    I’m impressed that you’re a do-er and all, but come on – you’re getting older and it’s time to ratchet up your game.

    E-beams! Old Electron microscopes are frustrating and fun at the same time. Yes, you can (or could) buy old process equipment to make chips, but if you’re ready to shoot for the moon on a budget… well, up a little current and you can be rocking like it’s… well, 1969. Or maybe 1972. Your choice.

    You can get your HV excitement slice figuring out how to dope the wafers. You’ll want to hit up used book sellers and start digging mid to late 60s Electrochemical Society books. Seems to be up your alley, anyway. And if you can’t jump on the direct fab bandwagon, you can try your hand at lithography and masks.

    I can’t recommend old-ish electron microscopes enough. It’s hard core, and makes keeping cutting lasers in production look like child’s play. You get to learn all about motion control, precise beam focus and control, thermal issues (are you man enough… well, woman enough, anyway… to figure out how to create a 1 degree C controlled environment to keep the place thermally stable, and then deal with rotating magnetic fields…
    It’s equivalent to becoming a black-belt, and a lot of it is just discovery.

    Naturally, you won’t make the same mistake I did and fall off the wagon and into destructive cellular tomography. The first time you put your initials on a blood cell that survives the process, well… Let’s just say that Mary Godwin’s little romance novel has been a real source of inspiration for our little group. :)

    Of course, it isn’t anywhere as cool looking as a high voltage thumper; but to each his/her own.

  8. I was at swapfest (MIT flea market) last week and one guy was selling a 10W CO2 laser scavenged from medical equipment for only $175. I considered buying it to build a laser cutter but decided I don’t have enough time or room in my apartment. If anyone else is interested though, the guy’s email and phone number (Glenn) are on his website, He doesn’t know anything about the hardware, the laser doesn’t have a power supply and probably needs half a dozen other parts (he doesn’t know) but the price is right.

    Note that he’s in PA and shipping the beast doesn’t look cheap.

  9. And what happens when the stuff gets on the silicon? won’t it just burn?

    My cutter has a pressurized air stream (50 psi) coming out of the nozzle, and the whole thing is vented with suction.

  10. @Bilbao Bob,

    You forgot regular diagnosis and repair of the electronics, which consists of huge modules containing probably 1,000 TTL and various other chips total. Guided by schematics in Japanese. Which must have originally been on A0 sized paper, but were at some point reduced to letter size, and then sent through a low-resolution fax machine; because that’s the only documentation you can still find.

    I for one am happy I will never have to see the innards of an old SEM again!

  11. Meh, boards are boards.
    Hunker down with a Huntron and/or a good meter and start shooting each component individually.

    You have an hour… ;)

    This is so beyond me that I would pay admission to see it.

  12. Crap had!!
    Silicon!!! Silicon!!!

    No e!! Although she did use siliconE to glue the silicon wafer done.

    Cone like, a cone one your head for being a dumbass. Con like the guy in prison who wants to violate you with his caulking gun.

  13. @Westfw –
    Sorry, she’s just a name to me… I know a lot of smart and gifted women, so I don’t have the whole fetish thing going that a lot of geeks seem to. To be honest, for a while I had her confused with Jeri Ryan. She seems cool, anyway. I wish I was more knowledgeable about the whole “scene” thing, but, well, you know. :)

    @Chris –
    Oh, man, I feel your pain, brother. And I’m not usually the guy[s] doing the work. It seems like every piece of high-tech medical gear I’m forced to work with is a crappy half-baked prototype rushed into production. All of it. I can’t name names, but it seems that the likelihood of equipment being crap with support engineers on site every other week is directly correlated to price. And the software… well, anyway, yeah.

    Sorry, didn’t do my research. I bow to your incipient awesomeness, or at least I would if my knees weren’t sore from messing with the wheels of my electra. But we still expect great things from you.

    “After all, a girl has got to have her standards.”

  14. @stryder-m2k

    SEMs are like old pinball machines multiplied by 1,000. I found myself wanting to go in, rip out the useless electronics and then redesign them from scratch. Old units are horrible – You know how (well, probably not, but I’ll use it anyway) the business world is filled with half-baked middleware apps put together and maintained by outsourced indian programming teams? Same thing.

    Half the time, when encountering a part, you will discover that it’s the 80s or 90s equivalent of “cut and paste” glued together from the manufacturer’s application book and cobbled into operation. Useless complexity because the system was put together by guys who had lost their edge, and roughly the equivalent of building a PC from TTL logic long after FPGAs became available.

    There is a distinct trend of trailing-edge technology in the medical world, resulting in bad clones of the same design with a handful of differences put in to get around patents.

    Why is it all so crappy? For the same reason that pinball machines stopped evolving – pretty soon, all the patents and mergers meant that lawsuit barrages followed anyone trying to put a new model back on the market.

    With pinball, people say that the market died because of maintenance and space issues, but the biggest killer was that pinball could no longer evolve* due to a market stranglehold by one or two big manufacturers with legal staffs who were better at stomping out the competition than the engineers could ever be.

    (* in terms of reducing maintenance and production costs, and to a lesser extent in adding new features)

    The biggest issue is that on older systems “onboard diagnostics” is more of a checklist item used for marketing hype item rather than being useful, and in a properly designed system shouldn’t really be necessary.

    I have great hopes for our next purchase, though. Linux is sneaking into the medical research world by leaps and bounds, and it’s about time. The sad thing is that they have to almost hide it from the customers.

    Also, we will very soon reach a point where the SEM is about as necessary as a mechanical butterfat measuring device. I pray that the delay is measured in months rather than years.

    Disclaimer: We’re not doing FDA approved party tricks. Closed course with non-board certified Phds driving. Don’t try this at home. You may experience dizziness, rashes, vomiting, pruitis and other side effects. A strong urge to run naked through the streets railing against GM meat products may occur – see your Doctor if this happens, or if other unexplainable behaviour occurs, such as disbelief about the size of your paycheck. Do not attempt to operate your SEM while under the influence of drugs or alcohol.

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