H-bot style 3D printer moves bed for Z-axis

h-bot-style-3d-printer

Check out this 3D printer (translated) which [Arkadiusz Śpiewak] has been working on. When sending in the tip about his project he made the important distinction that it isn’t finished, but he has reached that critical threshold where he has printed items with it.

He decided to go with a design that is sometimes referred to as an H-bot. If you’re completely unfamiliar with it, you may find this H-bot design article helpful. The gist of it is that this technique makes it so that the motors used to move the extruder along the X and Y axes are themselves stationary. One large timing (toothed) belt makes a circuit around the top of this cube in the shape of the letter H. This is a bit easier to see in [Arkadiusz's] rendered image found after the jump along with video of an early print test.

The Z axis uses two motors mounted along the bottom of the cube. These raise and lower the bead, instead of moving the extruder itself. All-in the printer should have a maximum object size of 30x30x30 centimeters. It’s being driven by a Smoothieboard, which was mentioned quite a bit when we were discussing using the RA driver board with a 3D printer.

hbot-zaxis

Comments

  1. J says:

    Isn’t this true for most 3D printers? I believe the MakerBot ones move the bed as well?

    • Wulfnor says:

      Yes, makerbot replicator, ultimaker, tauntillus are moving bed in Z axis. But on replicator you are also moving X motor. And on ultimaker and tauntillus x-y gantry cant take to much load, thats why they are using bowden extruder.
      On h-bot i get both, lght weight x-y gantry, but also enough strenght to have direct drivern extruder, or even dual one.
      Its just diffrent design, it has it good and bad sides.

    • Bitflusher says:

      In addition to the consumer/hobbiest 3d printers, most commercial 3d printers move Z instead of everything else.
      The RepRap Mendel (and its many derivatives) uses a bed that is stationary on the Z axis to make it more compact.

  2. John says:

    The smoothieboard site doesn’t look like it’s been updated for a while. Anybody know how active the project is?

    • arthur says:

      The wiki ( documentation ) itself is updated often, but we don’t use the blog much because it’s not very convenient to use. I’ll put some work into that, and start doing more frequent updates.
      The community really revolves around the IRC channel ( #smoothieware @ irc.freenode.net ), the website is just for documentation.

  3. Justin says:

    Isn’t weight distribution an issue in this setup?

    • Wulfnor says:

      In what way? Mass thats moving on this printer is very low comparet to prusa, on h-bot only x axis and extruders are moving with fast speed. All stepper motors are stationary besides extruder one. Misumi 20×20 profiles are also very rigit.
      Aslo i have ability to use big nema 23 motors, that are cheaper for same or greater torque, and im not addind any payload.

  4. Thomas Thomas says:

    Oooh it moves the bed for the Z axis! Wait didn’t the RepRap Darwin do that? Oh ya. It is cool not moving the X axis motor though!

  5. Adrian says:

    I’ve never seen this H configuration before, its absolutely fascinating. Thanks for exposing me to this new design!

  6. Mr Kaizer says:

    This H-belt-design looks really interesting. It seems you need less smooth rods for the x-y-axis than for exaple the Ultimaker and less bearings as well.
    Does it have a particular disadvantage?

    • Wulfnor says:

      You need 6 idlers for belt placed in such way that belt is always parralel to smoothbars and itself, so all radiuses have to be exact. All those bends and lenght of belt byitself needs some force to move belt around, so you need more torque, thats why im using nema 23 1Nm motors.
      Other than that o dont se any big disadvantages, its just less comon used design so had some design problems on the way.

  7. drmd says:

    I am working on a similar design for about 6 months now and i can tell you just by looking at your acceleration and speed(very low) in the vid that you have the common bed vibration/shaking problem associated with designing floating Z lift axis. Let us know if you find a solution to the problem other than software.

  8. James Howard says:

    It looks like it will be a nice printer when you get it all done. And thanks for mentioning the RA board in the article. http://www.elefu.com/index.php?route=product/product&product_id=51

  9. Dan says:

    Anyone wanting to see a bit more should search for the original inventor Ian Moyer,

    There are two belts not one really long belt.

  10. joy says:

    3 d printer is a great invention
    I am working on a 3d printer extremely similar to the one presented here. Hopefully I get it moving by the end of next week.

  11. Chris says:

    I built a somewhat simplified version of this printer

    http://3dbotz.com/?product=3dbotz-m2-8×8-diy-kit

  12. carl-f says:

    Love the design, I am making my own H-bot version, but using v-slot with no linear rods and using a 8″x12″ bed from maker farm.

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