Spare rear panel?

Discussion in 'Getting Started' started by orcinus, Aug 8, 2019.

  1. Jason Chodakowski

    Jason Chodakowski Active Member

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    This is how it happened for me although I did use locktite. Just one corner that was under some small stress that I was able to relieve. No change since.
     
  2. Greg Holloway

    Greg Holloway Administrator
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    did you use threadlock on the M8 bolts and feet? Can you post a photo of the cracks?
     
  3. cj.matthes

    cj.matthes Member

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    I did not use any threadlock on the M8 bolts holding the panel.
    toolchanger_panel-crack.jpeg
     
  4. Greg Holloway

    Greg Holloway Administrator
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    The bolts holding the panel are M6, the bolts holding the top and feet are M8 thread. Did you apply threadlock to the M8, or any other bolts on the machine?

    I'm not looking to point fingers, we are gathering data on the failure mode(s).
     
  5. cj.matthes

    cj.matthes Member

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    I did put threadlock on the bolts as instructed by your manual/installation guide, but not on the M6 bolts holding the panel. The build took place fall last year.
     
  6. Greg Holloway

    Greg Holloway Administrator
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    ok :)

    Using threadlock on the M8 bolts leads to cracking of the acrylic panels as the thread-lock off-gasses and seeps out to attack the acrylic. The manual was updated instructing people to not use threadlock anywhere on the machine a month or so ago.
     
  7. Nibbels

    Nibbels Well-Known Member

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    Yes, äh "No" it is not stiff enough ^^.
    I now figured out why my z offsets are always moving.

    -> But to be honest, I did not install the plexiglas panels left and right.

    Started a print and the TC drew a perfect first half layer. Then I lifted one side of the printer and the whole z offset got totally bogus.
    I guess a slight lift on one side changes +-0.15mm without the plexiglas panels. (And in case I would install them, they have to carry the load. -> cracks?)

    So I guess I really will cross the sides using some flat aluminium profile. Or maybe I get some 45° 30x60 Profile which perfectly fits into the sides.
    I dont need the sides for filament as I mount them atop of the printer and wont use bowden.
     
  8. blarbles

    blarbles Well-Known Member

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    I installed a cross support in the front and it has been working out good for me. The front needs 410mm extrusion.
    2020-02-18 17.11.54.jpg
     
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  9. dc42

    dc42 Well-Known Member

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    I was considering installing a front extrusion, but at the bottom instead of near the top, and replacing the two front feet by a single foot under the middle of it - thereby keeping the frame square even when the TC sits a bench that isn't level.
     
  10. Jason Chodakowski

    Jason Chodakowski Active Member

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    What is that blue you did the tool-head cover in?
     
  11. blarbles

    blarbles Well-Known Member

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  12. Nibbels

    Nibbels Well-Known Member

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    Screenshot_4.jpg Screenshot_2.jpg
    Screenshot_5.jpg

    I recently bought some parts and installed them today. The black connection plates are made of 3mm aluminium. With those installed the TC seems to be quite stable.

    But now I have to test reliably
    whether the offset disappears and
    whether the surface scan is still valid after moving the TC on uneven ground.

    EDIT: Yes I couldnt wait: So I rescanned (G29) the surface and started a print.
    Then I stuffed one piece of cloth after the other under each of the pillars. Each lift was no longer visible in the print.
    But I have to put the printer on an absolutely flat surface for the next days, loosen the struts and tighten them again, because my G29 scan showed +-0.6mm.
     
    #132 Nibbels, Feb 26, 2020
    Last edited: Feb 26, 2020
  13. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    I just got my toolchanger today!

    I am wondering whether using aluminum connection plates (maybe 100mm on a side) in the bottom and top corners ( without any extrusion cross bracing) would be sufficient.

    Any thoughts?
     
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  14. Nibbels

    Nibbels Well-Known Member

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    My pictures are atop. I guess there should now be some footnote on them:
    I had some software problem while I fixed the stiffness in that way! So there were at least two different causes for one problem. (https://forum.e3d-online.com/threads/layer-heights-different-between-tools.3637/)

    1) When my TC was on an uneven surface I was able to change the Z-Offset from nozzle tip to bed by applying some force to the top of the toolchanger. -> Without side panels!
    2) My TC had problems printing even layers. That was fixed with RRF 3.01 RC11
    3) I did suspect the tool grabber to grab unreliably but when dc42 fixed the 3.01 versions I got good results. So forget "3)" for now.

    Now I fixed both but cannot tell what caused the most problems. And I dont remember when I first switched to a firmware RC version which was broken. What I needed was to eliminate one of the variables. -> I dont want to communicate that gregs construction is bad.
    I still never did add the side panels because I now have the solution atop.
    In case you get great results with edge triangles to support the stiffness please tell us. Try it.
     
  15. jwalker55

    jwalker55 Member

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    All of my M6's and M8's came with threadlock pre-applied. Is this intended? Since it's already dry, it makes finger tightening the acrylic panels impossible, and it's really difficult to tell if they're over-tightened.
     
  16. Greg Holloway

    Greg Holloway Administrator
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    Yes, that's intended. I need to update the documentation!...
     
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  17. jwalker55

    jwalker55 Member

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    That's what I assumed. Thanks Greg!
     
  18. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    After looking at the actual hardware, I think that a triangular corner piece probably would not make the stiffness significantly greater. What might work much better would be to continue with extrusion along the bottom edge, between the vertical extrusions, attached to the other extrusions and the bottom plate, to stiffen the bottom. I think the bottom plate has some flex in it and triangular corners, unless they were quite big, wouldn't do a lot to stiffen the plate. Another approach might be to use plate aluminum similar in thickness to the top plate or double up the bottom plate and creating a laminate out of 2 sheets of the existing aluminum. I would think the layers would need to be adhered together to provide the extra stiffness (maybe water thin superglue wicked between the sheets clamped together... ? )

    @Greg Holloway, I am sure you have thought through this and much more. What are your thoughts?
     
  19. Greg Holloway

    Greg Holloway Administrator
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    Side Panels work great for me. If i were to do anything I would put an X shaped brace in place of the side panels, but as they already do that job anyway, make them in aluminium.
     

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