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3D printing with a CNC machine

Discussion in 'Concepts and Ideas' started by Hexag, Sep 11, 2014.

  1. Hexag

    Hexag New
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    Hi everyone !

    I was wondering if it is possible to make 3D printing with a CNC machine. I was especially thinking about installing a 3D printer extruder on a CNC machine, like this one : http://www.openbuilds.com/builds/openbuilds-ox-cnc-machine.341/.

    I saw a few people doing it with the Shapeoko 2, for exemple : http://www.shapeoko.com/wiki/index.php/3D_Printing_Mach3. But, thinking about that, I was like : is it really a good solution ? And few days ago I saw these two machines :

    · The Microfactory : https://www.kickstarter.com/projects/327919589/the-microfactory-a-machine-shop-in-a-box
    · The FABtotum : http://www.fabtotum.com/about

    Seeing that, I thought that my project was maybe not so crazy.

    The idea is to build an hybrid machine, based on a CNC machine (like the first one mentioned). The head of the machine would be interchangeable with a CNC spindle and a 3D filament extruder.

    Of course, that involves some changes from the CNC base, like extending the Z-axis to have a decent build size for 3D printing. The goal would be to reach a 100 micron resolution. Notice that the print time doesn’t matter.

    So, my real question is : What do you think about my project ?

    Any answers or comments would be appreciated !
     
  2. Rob Taylor

    Rob Taylor Master
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    The idea is fine, and 0.1mm is easily achievable, even using belt. We have a couple of hybrid machines being worked on on the forums, though not by me- I'm more a laser/mill/subtractive kind guy.

    Check out @Brian Slee's Ultimo delta hybrid bot thread here: http://www.openbuilds.com/threads/ultimo.454/ - based on pick-n-place-inspired delta bots. He's crunching hard on it now for Maker Faire Orlando, but he should be back in a few days to discuss it some more.

    There's another one, though I can't find it now. I think someone was adding a laser engraver to the OX or something. (Edit: It may have been this CNC laser addition by @Tweakie: http://www.openbuilds.com/builds/co2-laser.565/)

    Spindles are a lot of mass and exert a lot of force, both pushing off of and digging into the workpiece, which is pretty much the opposite of an extruder. You're going to have to over-engineer your printer in order to make it useable as a spindle. 0.1mm resolution is also quite low for a CNC mill, so you may want some form of switchable resolution. For information on driving, speed vs. resolution vs. torque, I wrote up this thread: http://www.openbuilds.com/threads/the-big-thread-o-linear-motion.678/

    Hope this helps.
     
    #2 Rob Taylor, Sep 11, 2014
    Last edited: Sep 11, 2014
  3. Hexag

    Hexag New
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    Thank's for this so quick answer ! I will quietly think on your ideas and I will give you my feedback later ;).
     
    #3 Hexag, Sep 12, 2014
    Last edited: Sep 12, 2014
  4. Hexag

    Hexag New
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    Hi !

    During these few days, I really thought about my project. I still hesitating between building an hybrid machine or two distinct machines.

    Building an hybrid machine will obviously reduce considerably the final cost. However, I’m afraid the machine will do both works (3D printing and CNC machining) but not very well…

    Building distinct machines will permits me to really focus on the specific parts of each machine and get considerably better results.

    What do you think about ?
     
  5. Rob Taylor

    Rob Taylor Master
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    I came to the same conclusion. I originally liked the idea of hybrid machines, but as I've researched it more and more, I've come to realise that the differences between them are too great to really allow proper hybridising without actually having multiple axes on each machine- a lightweight, high resolution gantry for a laser over 3ft square, a lightweight, low resolution gantry for a printer over 1ft square, and a heavyweight, high resolution gantry for a mill head over 1.5ft square, for example. It seems like an engineering challenge in search of a problem to solve. Does anyone have so little shop space that they can't dedicate two or three 3x3 foot squares to multiple machines? If they can't, is the machine really justifiable in the first place? How about building a smaller, desktop version instead? I'm not sold on the hybrid idea, but then again I'm also looking at it from a commercial point of view rather than a hobbyist point of view. I want to put my machines to work!

    So yeah, I think you're right. I'm building separate mill and laser machines, because for me, at least, they're not really combine-able.
     
  6. Hexag

    Hexag New
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    So my decision is taken : I will build distinct machines. Thank's for your contribution, it was really helpful :thumbsup:.
     
  7. Serge E.

    Serge E. Journeyman
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    Except maybe for the 3D printer, most of these machines have somewhat limited Z (ex: CNC is often used for engraving or 2.5D with a few inches of Z travel). One with limited room could stack the individual machines ? Vibration might prevent running all machines at once ? I could see the CNC/mill closest to the ground, laser or such up above and the 3D printer actually to side since the one needing height. The whole thing could have a countertop for stand up work, storage, ... Everything would take no more room than a large work bench ? If I look at how I setup myOX, one could get away with a 6.5' long x 2.5' deep and about 39" tall table/workbench. Make it ~2' longer, and the 3D printer could hide in a space about 2' w x 2.5' d x 3+' tall. All three machines would thus be quite large as well. The resulting workbench top would be 8.5' or so long/wide x 2.5' deep. :rolleyes: I might just have to rework my garage's one corner ...
     
  8. DiggerJ

    DiggerJ Journeyman
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    My build is Babe (the blue laser) OX. It holds a removable router for cutting, ha can be swapped for a laser by loosening 2 screws. The reason it made good sense is that the router/laser use the same 0,0 coordinates so it is an easy swap. Once the laser is focused at a set Z height, I can easily be reset to that setting to restart using the laser.

    I am building a separate 3D printer, as I hope I have reason to use them at the same time, and it is the odd man out of the three.
     
  9. Rob Taylor

    Rob Taylor Master
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    When I say mill, I mean actual gantry mill, not a table router. If you're just going for a table router, then the resolution, vibration and stiffness issues are certainly lessened thanks to the reduced accuracy requirements of wood. Personally, I'd want to run a laser in a dedicated sealed/vacuumed enclosure like the professional units to avoid getting dust specks on the mirrors/lenses from the other machines. I may also even want to run them in different rooms (laser in my office, mill in the shop, for example).

    But that's just me. For lightweight gantry routing tasks, your method may have some possibilities.

    This makes sense. Using a laser diode as a direct swap in a gantry router is the best shot at hybridisation, I think. I may even give it a try at some point on a light-duty machine for slicing and decals.
     

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