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Dual Direct Drive Extruders Concept

Discussion in 'Mods and Upgrades' started by Tony Janus, Nov 8, 2014.

  1. Tony Janus

    Tony Janus Member

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    [​IMG]

    Hey all, so here's my design so far. Sorry I haven't been around for a while. Looks like you and I had very similar ideas for direct/bowden. I've got the one side risen to compensate for v5 height. Hotends get inserted and fixed to the mounting block. Then those get put through the x carriage with the extruder placed ontop, which is then secured in place from underneath. I still need to design the carriage, but as long as the extruders are true to their CAD files, then the snug fit should level them perfectly, and they fit between the bearings with enough clearance for fan ducts. If not, I'll have to implement some kind of spring mechanism for level similar to yours.

    I'm going to try to implement fan mounts similar to this: http://www.thingiverse.com/thing:364650

    But I'm worried by doing so, I'll be forced to remove the cover.

    I'd love your files to try em out, I'll shoot ya a PM in a bit.
     
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  2. Mike Kelly

    Mike Kelly Volunteer

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    That design looks awesome man. I like the solution you came up with for the v6 and v5 integration. Though do you have any means to level them? It's pretty much impossible to assemble them exactly to spec and a little bit of difference can be very annoying to deal with.

    I feel like those fan mounts would have too much back pressure to get decent flow. Also if you did that you would definitely lose some Z travel.
     
  3. Tony Janus

    Tony Janus Member

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    That does make sense about the fans. I'll probably have to figure something else out. I'd also like to check, maybe with some stronger fans I'll be able to mount them elsewhere and run some tubing to the hotend, but all just conceptual stuff in my head right now.

    As far as leveling the two hotends, I'm not really sure what mechanism to use. I have some compressions springs lying around from an old upgrade that didn't work out, so I can try using those. If you don't mind, I'd like to use your leveling design as inspiration? I don't really see another way to do without dramatically increasing complexity.

    Also have a quick question. I've been commissioned by my cousin in Europe to print out 50 or so invitations to her art exhibition at the Academy of Art. She's having my print out a pair of interlocking hands, and she wants it so that when the hands are spread apart, the text of the invitation is visible on the palms. She wants them printed with the palms approx. 7cm in width. Seems like it would be very difficult to read any text at that size, if the text even prints out.

    Point is, I need to get this dual extruder finished soon, because from what I'm seeing, I need to print the hands with a .4-.8 nozzle, with the text a different color and possibly out of a .25 nozzle I have but haven't tested yet. Would this be my best option you think? The hands stand on a flat surface from the wrists, which means that's how they'll be printed. I'm still going over the design with her, but wanted to get some opinions before I talk with her again. Thanks much. Pic below:

    [​IMG]

    [​IMG]
     
  4. Galaxius

    Galaxius Well-Known Member

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    I think it was Ziggy they used a blower style fan and tube on his Robo. I think it's on Thingiverse too.
     
  5. Mike Kelly

    Mike Kelly Volunteer

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    Radial style blowers are the way to go for a tube run. I picked up a huge radial blower from sparkfun that could probably push decent CFM through a meter of tube. I'm thinking about mounting it up top and running tubes to the hot ends.

    Ziggy's design doesn't work with an enclosure though.
     
  6. Tony Janus

    Tony Janus Member

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    Gotcha. I pulled a centrifugal fan out of the old casing for a GTX 780 (put watercooling on em) and printed out a case for it. Just need to print a 5/8ID tubing adapter and figure out which wire is pwr and grnd.

    Not sure if I'll be mounting the fan on the case with a long tube attached to some kind of bracket on the x-carriage or to the carriage itself. Depends on how flexible the tubing is I guess and if I can put enough for it to bend as needed without breaking off.
     
  7. Stargrove1

    Stargrove1 Member

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    Mike, I started using the motor from your post, I found that it gets very warm, from the data sheet I could see that the current is at only 0.4A at a coil resistance of around 30Ohms. At 12V this should fit, does the motor heat up like this in your usage too?
     
  8. Mike Kelly

    Mike Kelly Volunteer

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    Yes it does, you need to tune down the current on the stepper drive. I just do a dumb calibration. Tell it to extrude 100mm, then turn back the amperage until it starts to stall, then slowly turn the amperage up until it starts extruding again. Shouldn't get too hot from then on.
     
  9. Galaxius

    Galaxius Well-Known Member

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  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Simple, effective, genius.
     
  11. Mike Kelly

    Mike Kelly Volunteer

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    That's how the makerbot 2x is apparently leveled. I have one printed but never needed to level it.

    Personally I think it's a terrible approach. With my design I can adjust mid print if I need to.
     
  12. Stargrove1

    Stargrove1 Member

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    I have some questions about your design:
    • Why did you move the x-axis switch to the carriage?
    • Whats the second micro switch pointing downwards for? (z probe?)
    • How works the fine adjustment of nozzle height?
     
  13. Mike Kelly

    Mike Kelly Volunteer

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    1) I was hoping to eliminate all wires on the X idler. I don't like having those wires there so I'm trying to minimize the number of wire runs.
    2) The Second one pointing down was an attempt to have the X carriage act as a Z probe. Turns out the carriage does not provide enough force to trigger the switch so that idea was abandoned.
    3).


    Cut away view of height control:
    [​IMG]

    The order goes:
    • Push in the M4 nut
    • Screw in the M4-25mm to create a post, ensure on one side the part fan holder is in place depending on if you want it front or rear facing
    • Place the spring into the housing
    • Insert E3D and j-head plate over assemble
    • Secure almost fully tight using the M4 Lock nut

    The lock nut acts as height adjustment by using a spring to raise the nozzle.
     
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  14. Stargrove1

    Stargrove1 Member

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    I always try to avoid to much cable at the carriage.

    Thanks for the explanation of the adjustment mechanism, I need something like this for my next extruder. From your experience, do you think it would be possible to lift/lower the nozzle only at one side and use a hinge at the other? The height correction should only need around 1 mm I assume, that means the change in the angle should be less than 1° do you think this would this affect the surface or the whole print result?
     
  15. Mike Kelly

    Mike Kelly Volunteer

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    You have to have a wire bundle there anyways, so why not add 2 more? Honestly I need to add a strain relief to hold the wire harness in place, then no tension will be put on the wires at their connection points as intended for motion. For me I got annoyed about how many times my x axis switch wires broke and thought this the better solution.

    I think a hinge would work fine. Honestly with my plate design it kinda has that built into it. It might be possible to have height adjustment just with a plate hinge and no complex spring mechanism.

    I asked about the angle question before and the general consensus was a slight off angle won't be too bad.
     
  16. Tony Janus

    Tony Janus Member

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    Hey all. So here's where I'm at. Have the x-carriage and mounts for the most part done, but rough looking. Decided to not continue on a v5/v6 hybrid and picked up a metal kit for the v5. So now it's just a dual v6 carriage, but I'm going to make versions of the mounts for bowden or direct. Still deciding on which of the many extruder designs I'm going to use. Here's images so far.

    carriage:
    [​IMG]
    mount a:
    [​IMG]
    with hotends:
    [​IMG]
    mount_b:
    [​IMG]

    considering using the extruder from here, removing base and attaching so that it prints with mount_a:

    http://www.thingiverse.com/thing:550788
     
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  17. Mike Kelly

    Mike Kelly Volunteer

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  18. Galaxius

    Galaxius Well-Known Member

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  19. Mike Kelly

    Mike Kelly Volunteer

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  20. Tony Janus

    Tony Janus Member

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    oooo, really want to try adapting that. Wish they had supplied a materials list!

    I'm working on printing out the first prototype, but it looks like I may have to remodel the carriage. for some reason, using booleans to cut holes in my models is created some very, very weird artifacts. Some of the holes are filled, some parts where I joined 2 models together are only printing parts of one of the pieces, acting like the rest doesn't exist. Having issues.
     

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