X axis crossbar question

Discussion in 'Motion System' started by Andy Cohen, Nov 29, 2021.

  1. Andy Cohen

    Andy Cohen Well-Known Member

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    Iirc…
    During the beta test phase for the tc the X axis crossbar was originally made with carbon fiber. I was told that due to flexing found during beta testing this part was redesigned as a machined aluminum part and that’s what it was on final production. Is this correct?

    I ask because if we look at the pics of the newly announced Prusa XL (a tool changer with 5 tools) the X axis is simply the linear rail. No supporting crossbar at all! The X axis for this machine is quite a bit longer then the X axis from E3d and… Looking at their tool carriage and their tool design both look quite a bit more complex and heavier then the E3d design. As such it would seem they should see flexing issues… right?
     
  2. TstarkEngineering

    TstarkEngineering Well-Known Member

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    There is a video out there somewhere of Sanjay showing the deflection difference with a gauge. I will try and find it and post it.
     
  3. Paul Arden

    Paul Arden Well-Known Member

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    Would be pretty scary if the Prusa XL was just a naked linear rail. I've seen other designs that did that and could never understand how they avoided not just flex but stress already in the rail since they are designed specifically to be fastened to something rigid.

    Looking at the video from Prusa again though, while the supporting crossbar isn't really easy to see it must be there as there are fasteners through the linear rail in every second hole for the entire length. In a few shots you can just make something out, looks to be black whatever it is but it's not clear what material it is made from.

    I'm also curious why they felt the need to re-invent the coupling for the tool changer. The solution E3D used seems to work very well. Unless it has something to do with their use of the load cell. Have to say the automatic touch off for calibrating the nozzle positions looks very interesting.

    Will also be very interesting to see what they do for a purge and wipe solution as there is no indication of this in any of the material so far, and in my view it's one of the hardest bits to get right (now that all the other hard stuff has been largely tackled).

    Definitely looking forward to seeing better tool support in PrusaSlicer from this though as well.
     
  4. Paul Arden

    Paul Arden Well-Known Member

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    upload_2021-12-3_7-43-7.png

    Visible in this shot. It almost looks like a powder coated C beam, very hard to tell though and there are not really many good shots of it (and none from the back that I've been able to find).
     

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