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Dual extrusion mod for C2

Discussion in 'Mods and Upgrades' started by mark tomlinson, Feb 15, 2017.

  1. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I have started collecting the bits to try this out. I will update this with pictures and rambling discussion as I struggle with it :)

    Most of the design work is already in-place so it really is just adding the bits and modding the firmware.

    Granted this entire effort is a case of CAN I do that, not SHOULD I do that :)

    edit: Also, this is not a configuration that Robo ever intended so don't expect that they would endorse it. It is more of a cool thing that is relatively easy to do. Dual extrusion leads to a host of other issues that have nothing to do with how capable the printer is of using dual extruders.

    Going with dual extruders lowers the build area on the already rather small build plate -- at least when you are using both extruders.

    I will caution you that while straightforward, as far as modifications go, this is not for the faint of heart. It is a good bit of effort and it is questionable if it is really worth it for the bed size that the C2 has (which is probably why they do not offer the dual extruder kit). You sacrifice about 22mm - 44mm (across the X) of build size when you are doing dual extrusion prints. That is not an exact figure because it totally depends on what you are using each extruder FOR and how it is sliced.

    Still we wanted to do it "just because" and as a way to get more familiar with the machine*.



    *mission accomplished
     
    #1 mark tomlinson, Feb 15, 2017
    Last edited: Feb 27, 2017
  2. daniel871

    daniel871 Well-Known Member

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    Were I you, I would hold off on publishing this until after Robo puts out their own supposed kits (or at least waiting until it's clear they have no intention of doing it).

    I'm cynical as hell, but you really shouldn't be doing any of the work for them.
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    My printer, my time. I am likely not doing anything for them in that regard since it appears as though the work on the C2 side is done and given where the R2 is likely at in production terms they are not going to be able to redesign that now.

    Ultimately it may not even be doable. I will find out as it is minimal materials and only a little effort. It would make this C2 a really, really sweet little printer.
     
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  4. daniel871

    daniel871 Well-Known Member

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    I never said don't actually do it, just refrain from sharing it.
     
  5. Geof

    Geof Volunteer Moderator
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    @mark tomlinson lots of people would likely appreciate this thread. Got me intrigued ! Let me know if I can help
     
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  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Today's progress -- minimal since most parts are due in tomorrow. Just the printed parts and bits we had.

    Initial mount and route of Bowden motor and feed/extruder (on bottom):
    Bowden Back.jpg

    Bowden in.jpg


    Tabletop filament spool modeled after our big one :

    Filament holder.jpg
     
    #6 mark tomlinson, Feb 16, 2017
    Last edited: Feb 16, 2017
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    So, I did 90% of the work on this today. I forgot the silly connectors:

    https://www.amazon.com/gp/product/B00GWF65WY

    For the main control board (the Arduino/RAMPS replacement they use). So ... not quite working yet. Everything except the extruder heater power is landed.

    However with both extruders installed and otherwise wired it is still working fine as a single-extrusion machine.

    Had to fine-tune the Z offset a bit, but both nozzles are in-place and by my eyeball are pretty close to the same level WRT the bed. That is to say one is not lower to the bed than the other. It really helps that they are essentially identical hotends.

    While doing the single extrusion print the second nozzle is clearing everything nicely. I will have the other connectors tomorrow and will wrap up the wiring and try loading the modified firmware.
     
    #8 mark tomlinson, Feb 17, 2017
    Last edited: Feb 17, 2017
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  8. Geof

    Geof Volunteer Moderator
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    Hard workin on a Friday ! Great job !
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Sneak peak

    20170217_144804_small.jpg
     
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  10. Geof

    Geof Volunteer Moderator
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    Damn can almost fit a third in there
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Not really since they use the hole for some electronics boards and wiring, but it that were not there -- yup!
     
  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Sadly the hexagon I ordered in was ordered in haste and is the old style with the thermistor requiring the rubber boot :(
    Should work OK.

    I took a lot of pictures for the tear down and reassembly because there was a lot that was non-intuitive...
     
    #13 mark tomlinson, Feb 17, 2017
    Last edited: Feb 17, 2017
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  13. Geof

    Geof Volunteer Moderator
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    Next mailing I send your way I'll send you the 3 r1+ hexagons I've got
     
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  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    While a pain if you don't have the connectors (and I didn't) the way they have all of the connector interfaces between the boards is actually righteous. It is well designed in that regard. Disassembly is very easy even to parts like the hotend.

    edit: Link to the connectors much further down-thread. I found the correct ones
     
    #15 mark tomlinson, Feb 17, 2017
    Last edited: Feb 18, 2017
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  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Here is the completed top end view. I will post the entire build photo set tomorrow when we finish the last connectors. It looks quite nice. I will want to add those bushings for the Bowden ()see where it goes into the top on the hotend?) on the input/output of the extruder at some point as well.

    20170217_211037_small.jpg
     
  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I was concerned that the pin definition used in the firmware for the C2 might not call out the second extruder pins, but looking at the header file it seems as though it does. We will find out when that last connectors get here today.
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Pictures coming in a few. We were having issues with the extruders not working correctly.
    So in a flash of inspiration we remembered to reflash the Flash EEPROM and then from OctoPrint the extruders would heat correctly. There is an interesting bug in the LCD code however. It sees both extruders and you can tell it to heat either, but when you do this.. .only the first extruder will actually heat :)

    Further the wires we used to jumper the power down from the top board to the bottom board which carry the extruder heater power are insufficient to the task. They get too warm. I need to scale them up. We only had wires with 24 gauge wire and that is too small. We have ordered the correct connectors (JST EH connectors in case anyone wants to know) and when those come in I will reassemble it with 18 or 20 gauge wires to avoid a meltdown.

    So at this point it actually does work. We have everything functional. The last bits to tweak are things like the extruder offset in the firmware (looks to be about 21.6mm, but we may need to tweak it more exact). We also just have the wires to replace and re-land.
     
    #18 mark tomlinson, Feb 18, 2017
    Last edited: Feb 18, 2017
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    As far as Marlin changes, the extruder offset appears to 21.6mm on the X axis. We will test and fine-tune this when the connectors get here. There were few other things to change number of extruders was the big one. There were compilation issues stemming from Marlin when number of extruders = 2 and PIDTEMP = TRUE. Not sure if this was ever completed sorted on the Marlin side so for now we are just disabling PID control.
     
    #19 mark tomlinson, Feb 18, 2017
    Last edited: Feb 18, 2017
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    And so the pictures begin. They are pretty much in order of disassembly/reassembly.
    They show all of the basic steps. If you have any questions I can fill in details.

    20170217_132816_small.jpg
    20170217_132952_small.jpg
    20170217_132816_small.jpg
    20170217_133331_small.jpg
    20170217_133436_small.jpg
    20170217_133718_small.jpg
    20170217_133802_small.jpg
    20170217_134019_small.jpg
     

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    #20 mark tomlinson, Feb 18, 2017
    Last edited: Feb 18, 2017
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