Magnet in tool instead of grub screw to increase retention?

Discussion in 'Motion System' started by W1EBR.Gene, Sep 1, 2020.

  1. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    I am finding that the bowden tools are held in place in the tool dock but the Hemera tool, due to the weight distribution tilting it forward, doesn't always get grabbed by the dock magnet. Has anyone tried using a 2nd magnet (with the polarity opposite of the dock magnet) in the tool instead of a grub screw?
     
  2. Paul Arden

    Paul Arden Well-Known Member

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    It sounds like you have a similar issue to the one I discussed in this thread. For me whether it docks solidly is a very touchy combination of the stick out of the fan shroud, the height of the piece that connects the top of the stepper to the receive and the position of all of the screws that go into the t-nut slots in the Hemera.

    I think it will be different for everyone unfortunately but after a lot of loosening and tightening and reducing the depth of the fan shroud and the height of the receiver connector I hit upon something solid. However I had to tune this individually per tool. I think there is just a lot of room for adjustment in the design, enough to make it fussy.

    The one thing that really helped me was once I realised that if the tool plate top doesn't sit very close to flush with the top of the top plate of the motion system then you're going to have trouble and I found that adjusting for this (which was useful because I could see that without running any tests) got me close enough to get it working.

    Multiple magnets could even be too strong? Particularly since the tool changer will need to separate them purely by pulling them apart (try that by hand, with some magnets you can only get them apart by shearing them). I'm sure there is enough torque in the steppers to do it, but I'm guessing there is a balance to be had.
     
    Jason Chodakowski likes this.
  3. 1013D

    1013D Active Member

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    best option would be some sort of positive latch mechanism that is disabled by the toolchanger latching onto the tool. Don't think there is a lot of room for it, but perhaps a lever that is lifted up by the rotating pin. this lever would unhook from a notch or something on the holding pins for the tool.
     
  4. Rene

    Rene Active Member

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    Just put something where the fanshroud hits the electronics panel to prevent the tool from tipping when docked. Or design the fanshroud, so there is a little bump aswell. See my design for reference: https://www.thingiverse.com/thing:4181892
     
  5. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Thank you, Rene! Did you think that having the part cooling fan only blowing on one side of the filament was a problem?
     
  6. Rene

    Rene Active Member

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    I had better prints when the partcooling was blowing from 2 sides. I don't have time to design a better fanshroud, yet.
     

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