Weird Laser Kinematic Ideas - Firmware suitability?


  • Moderator

    I would think that a CoreXY arrangement would be the ideal for a plotter style system like a laser cutter. The frame can be made very rigid very cheaply, the effector can be kept very light and travel very quickly.

    But maybe I'm missing something.



  • @phaedrux the whole objective is to print as large as possible with as small a device as possible. For as often as I'll be using it, and as large as it would need to be, a corexy for this project just isn't feasible in a nyc apartment.



  • @dc42

    The first idea would look something like this (obviously rough mock-up)alt text

    i.e. typical x gantry mounted on a y axis that literally just drives th whole thing back and forth

    The second idea, which is an even rougher mockup (i wouldn't use cart casters but it gets the point across) is just what it sounds like, a hang printer on wheels:
    alt text


  • administrators

    The first one would use standard Cartesian kinematics, The second one would need kinematics written for it, essentially a 2D version of Hangprinter.

    Both idea worry me rather. I can imagine the card rolling off the table and the laser burning something that it shouldn't (possibly you).



  • @dc42
    Funny how people think about things differently. One of my main positives of the second one is safety, it's small enough that it could be completely surrounded with a skirt like a brush or vinyl that goes all the way to the medium and no light would even escape. Obviously if used on a table it should have bumpers on all sides, though it's more likely I use it on the floor, personally.

    The real question boils down to how do hang printers work? If the z was controlled (by means of wheels in this case), would only using the 3 xy motors and leaving the z unplugged still result in proper xy movement (if using G92Z0 first so the machine considers itself homed), or does xy positioning actually rely on the z motor for more than moving the height and feeding enough line to make the xy moves reachable.



  • @clearlynotstef said in Weird Laser Kinematic Ideas - Firmware suitability?:

    ...it's small enough that it could be completely surrounded with a skirt like a brush or vinyl that goes all the way to the medium and no light would even escape.

    When working with metal laser processing I've seen smoke & particals have a detrimental effect on laser quality.

    How are you planning to control this and keep your optics clean if the work piece is on the floor and there is a skirt all around the cart?



  • @doctrucker good question! For this particular project, the medium is actually always underneath glass, specifically to keep it from burning as much as possible by limiting oxygen access, and also to keep it held down and flat. So the cart contraption would be riding on top of the glass and cutting through it.



  • What kind of wavelength and power level are you intending to use?

    I tried engraving through glass with a 2.5w 405nm laser, and I'm not sure if it was the heat from the work piece or the laser directly interacting with the glass but the glass got damaged along the lines. My intention was to help keep the work piece flat, but had to abandon that idea.

    (May revisit it for trying to cure UV soldermask, but that would be at much lower power levels, like 20mW or so)


  • administrators

    Bear in mind that the glass will reflect a significant fraction of the laser light back towards the laser, which could damage it. I presume you are using a visible or near infrared diode laser. CO2 laser light won't penetrate glass.



  • Hm, thought the UV spectrum around 400nm would pass though glass, but seems not to be the case, but that was the main reason to ask OP for the intended wavelength.


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