jubilee Z axis discussion

Discussion in 'Motion System' started by David Gilbert, Nov 4, 2020.

  1. David Gilbert

    David Gilbert Member

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    Here's me post a lot all of the sudden. Might taper off while things arrive from China. Anyways...

    https://jubilee3d.com/index.php?title=Specs

    ... interesting take on the tool changer. Many similarities and differences in the motion system.

    TBH... I've always been uneasy with the "motion system"'s Z axis. It strikes me that without due care, it could easily be bent. Comments?

    I've given consideration (not just seeing this) with a two leadscrews in front and one in the rear (or two in the rear) either with a Belt going around them all or with 3 or 4 motors. Sigh... complete overkill, but the multi-motor design doesn't need belts and is capable of accurate electronic levelling.

    Can some engineering grey beards convince me one way or another?
     
  2. Greg_The_Maker

    Greg_The_Maker Administrator
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    Could be bent? The Z-Axis is built like a brick sh!t house. If you manage to bend it you have done something horribly wrong.
     
  3. Rene

    Rene Active Member

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    *taking-notes-for-my-scripts*
     
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  4. David Gilbert

    David Gilbert Member

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    So ... no opinions on a 3 or 4 shaft setup? Part of my consideration is that you've deliberately make a 200x300 buildplate --- if I am intent upon a 300x300 ... that's 50% more leverage against the single post. Sigh. Anyone else with toughts on the jubilee?

    I am getting some good input from this forum. I have ordered 500mm long linear guides for the Y axis movement. I'm waiting for them to arrive to modify the DXF of your top and bottom plates and ship them off to someone who can cut aluminum. I already have all the t-slot --- so I'm just biding my time a bit before making a final decision on the Z axis.
     
  5. Greg_The_Maker

    Greg_The_Maker Administrator
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    300x200 is the biggest i would go with a cantilevered bed. After that I would go with three leadscrews much like the railcore. doing that does add ~3 x the cost and parts for the Z axis.
     
  6. David Gilbert

    David Gilbert Member

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    As much as I am a miser --- looking carefully at the cost/performance benefits of everything I buy --- you're pretty much confirming my thoughts --- that the 3 shaft design might be the safest play in my case. Given the height of the cantilever, the three shaft approach might even make a little more Z room available, too.

    The more I think about it... three shafts --- two in the front corners, one in back ... with 3 motors on the bottom ... that should work nicely. It should level nicely with a sensor --- I suppose you only need a height sensor on one tool --- levelling electronically almost seems like cheating, but compensating for my own fallibility electronically is attractive.

    If I use a Duet 3 with 4 tool boards --- I should have enough control to afford 3 Z steppers.

    Do I need to allocate one stepper control to the toolchanger head?

    So far for the Y, I ordered 500mm linear rails --- yours are 360 --- so the 500 should be more than enough. Room for bigger tools, too. When they arrive, after carefully inspecting them, I'm planning on modifying your DXF and sending that to be cut. My printer should then be 140mm or so deeper than your design.

    I'm getting excited.
     
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  7. Greg_The_Maker

    Greg_The_Maker Administrator
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    Yup, also the z-axis endstop is on the toolchanger head. no need for sensors on the tools, they'll only get ion the way anyway.
     
  8. dc42

    dc42 Well-Known Member

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    Docking sensors on the tools are handy though.
     
  9. Greg_The_Maker

    Greg_The_Maker Administrator
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    yup, those are.
     

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