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Friday, September 05, 2008

Ball-chain for X axis

This movie shows an X axis using ball-chain instead of drive belt. I built it on a design based heavily on Ian Adkins' lasercut RepRap, which I decided to attempt to simplify a little bit. As you can see, it appears to work. I'll do another run and tidy up the X axis - I just subverted part of Ian's design that looked handy.

One fly in the ointment is that I can't yet print the neat little lasercut toothed gears on my RepRap, though the new Arduino boards should help.

You can't see it here, but I had to elongate the holes for mounting the X motor into Ian's bracket. I'll do a quick redesign so that it can take the motor Ian is using and the ones I've got - plus anything between.

Vik :v)

6 comments:

  1. Cool!

    Have you any idea how repeatable/accurate the ball chain is in comparison with the toothed belt?

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  2. Yipee

    Cheap drives

    most excellent

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  3. Vik, maybe you just need bigger balls?

    (I can't believe I just said that in a technical context.)

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  4. I've not measured the play in it, but will do as soon as I get a stable axis put together. From just feeling it, I can't see there being a problem except as it gradually wears in.

    The glue failed holding the carriage together, so I've got to make a new one - I'd mis-interpreted Ian's routing lines as cut lines and sliced the edges off, hence the glue :)

    Vik :v)

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  5. russel, the bigger balls need a larger radius of curvature on the driving gear. I want to keep the driving gear as small as possible to maintain accuracy.

    Vik :v)

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  6. Postscript to G-Code converters already exist, although I don't known how close the G-Code output is to the G-Code used by reprap. From a quick search I found:

    ps2gc
    http://www.chiark.greenend.org.uk/~alanb/ps2gc.html

    A thread on cnczone called 'svg to gcode?'
    http://www.cnczone.com/forums/archive/index.php/t-29807.html

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