Salvaged robot arm makes a big 3d printer

Wow, building a precision 3d printer is amazingly easy if you can get your hands on an industrial-quality robot arm. [Dane] wrote in to tell us about this huge extruder printer made from an ’80s-era SCARA robot arm. It is capable of printing objects as large as 25″x12″x6.5″.

This 190 pound beast was acquired during a lab clean out. It was mechanically intact, but missing all of the control hardware. Building controllers was a bit of a challenge since the it’s designed with servo motors and precision feedback sensors. This is different from modern 3d printers which use stepper motors and no feedback sensors. A working controller was built up one component at a time, with a heated bed added to the mix to help prevent warping with large builds. We love the Frankenstein look of the controller hardware, which was mounted hodge-podge as each new module was brought online.

You can see some printing action in the clip after the break. A Linux box takes a design and spits out control instructions to the hardware.


  1. Hackerspacer says:

    since the it’s designed with servo motors and precision feedback sensors. This is different from modern 3d printers which use stepper motors and no feedback sensors.

    Closed loop servos with encoders are far superior tolerance wise to steppers.

    Modern, TRUE industrial 3d printers also use encoders. It’s mainly the cheap reprap/makerbot style machines that only use steppers.

    You need to constantly know where you are and where you are going so you can correct for that in real time.

    I have been looking forward to seeing a robot arm 3d printer :)

    • medix says:

      I’ll second that. It’s good to see someone who didn’t take the ‘easy’ way out. I’ve wanted to do this for years but never had the time / money / hardware to make it happen.

      If tuned properly, this type of servo gives you speed, power, AND accuracy all in one go.


    • Mikey says:

      Been thinking for a long time that what we really need is a 3D printable SCARA Robot Arm assembly, so we can get away from these damn cartesian bots.

    • Mikey says:

      I love that in the screen shot of the video (and at the beginning of it) it’s a robot arm printing another robot arm. XD

  2. birdmun says:

    I was sure I had seen

    this printer here. I guess maybe I saw the link to the video on another site I frequent.

  3. jaf says:

    man where do people buy stuff like this

  4. Oliver Heaviside says:

    The world is filled with old power hungry robots that no one loves. They’re much, much cheaper than foster children and will work for you night and day.

    However, it takes some work to get them usable.
    In many cases, the servos are fine, but the control hardware is gone/dead/undocumented and no one wants to mess with it.

  5. Eric says:

    Okay, that’s cool. I’m pretty sure something like this would also be quite readily adaptable to a 3d router.

  6. DudeGuy says:

    the smiley face is quite anthropomorphic.

  7. Wayne says:

    Holy crap!!! I learned how to do automation with one of those! The elbow direction change was a bitch to program.

    • Dane says:


      @ elbow direction:
      I haven’t actually solved that part yet in the kinematic model, it ends up working but VIOLENTLY jerking between ‘left’ and ‘right’ forward models. i mitigated it by placing a max-acceleration in that mode, but i’m always open to a more elegant solution.

      • Wayne says:

        I may have the source code for that still. It probably got purged during a hard drive swap somewhere along the line. It took a lot of effort to get that one code block to work and we shared it among each other after someone got it working well.

      • ferraro.robots says:

        Are you familiar with ikfast? OpenRAVE’s kinematics solver? It should handle it just fine.

    • Matt says:

      I also had big problems with the elbow dirction. But the printer is great.

  8. Kevin G says:

    That crazy B-st-rd.

    I has been wanting to say that with some of these hacks, but this one takes the cake. My dreams don’t even compare to what some people actually accomplish!

  9. John says:

    Too Cool!

    Now I know what to do with the two IBM 7547 SCARA robots in the basement. Luckily they came with the controls so I don’t have to be as ingenious as Mike.

  10. what is the laser for? rangefinding?

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