Sunday, August 11, 2013

Quick filament drive update

It's been a bit hot in my garage to spend any significant time in there, but I did get most of the XY Stage prototype running. There is supposed to be a second plate on the right hand side, but it's stiff enough without it, so I'll wait until it's a bit cooler to machine it.



There is a small geometry error in the carriage design, I set the spacing for the bolts used to secure the fishing line from the outside edge of the bolts instead of the center. This actually results in measurable error, about 0.4mm as the carriage moves from extent to extent across the bar in the H. So I need to print a new carriage.
The XY Stage is attached to the Arm based electronics, and I need to make a couple of changes to the firmware before I can do any real speed testing, since it doesn't really support acceleration. For point of reference in the video the motion is at about 140mm/s with instantaneous change in velocity (i.e. that's the jerk and velocity setting). I also need to add support for the modified kinematics.
In the mean time if I get a chance I'll set up a test to see if there is any measurable error accumulation over a few hours.

12 comments:

  1. This is really excellent work Rob - I think your work here is going to stimulate a flurry of filament driven bots. Kudos! My next project will be a core xy using this approach I think.

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  2. Rob, this is really amazing work. I've been gathering information to convert my defunct Eventorbot from a Kickstarter into a Core XY. I've been looking at the UConduit for some inspiration but I don't like the H-bot for the reasons that you've mentioned. I've also just recently run into the CoreCube SAKURA by ichibey on Thingiverse, but I wanted to try Spectra, being inspired by the Tantillus. Your idler is truly ingenious. I'm thinking of borrowing your core xy design and using a spectra or belt driven z axis, as I've had issues with my 5/16 threaded rod being overconstrained on my bot. Please keep us updated, and if possible, I'd love to use your design data. What software do you design in?

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    Replies
    1. I think you can use marlin to drive corexy.

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  3. which pulleys do you use rob?
    thanks

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  4. There is a little geometry slip in the carriage outline, I set the separating for the jolts used to secure the angling line from the outside edge of the jolts rather than the inside.

    blending machine

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  5. I'm currently designing a CoreXY printer.
    I'd like to know if you've made any further progress in your work?
    Its very promising!

    Thanks
    Chris

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    Replies
    1. I changed jobs and haven't had much of a chance to play with it.
      It works well enough, when I get back to it, I'll redesign the axis to be horizontal rather than vertical, a single LM8UU for the carriage leaves too much slop and introduces some unwanted motion.

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  6. I was pinning away for such type of blogs, thanks for posting this for us.3D Printing Geeks

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