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Dual Direct Drive Extruders Concept

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

  1. Stargrove1

    Stargrove1 Member

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    Hi Tony, is there enough space for the GT2 belt?
     
  2. Mike Kelly

    Mike Kelly Volunteer

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    Well EZStruder is just as the name describes. It's easy to use.
    I think your design may provide enough torque, but it's hard to know for sure without experimentation. A geared stepper is just a good way to do it. Best to keep the same design for both extruders if possible.

    Lookin nice man, keep up the work
     
  3. Tony Janus

    Tony Janus Member

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    There's looks to be about 4-5mm clearance between the motor and the attachment points. I put one on each side of the carriage because having those 2 attachment points seemed like the most stable with this config.

    I'm probably going to switch the pully/belt system out soon for a different system entirely. Still looking into it but a lead screw setup I think would be most stable as I could anchor the other end in a bearing between the two guide rails. Also planning on removing the top and constructing a more stable skeleton to give me better stability options. Looking less and less like a Robo and more and more like a custom every day.

    Mike, I ordered 2 of the geared steppers you suggested either here or somewhere on this board, I forget. These: http://www.omc-stepperonline.com/ge...ma-17-stepper-motor-17hs130404spg5-p-140.html

    Going to integrate them into the design and have 2 versions available. Can I use the Prusia calculator to calculate my esteps? (from here: http://prusaprinters.org/calculator/)
     
  4. Mike Kelly

    Mike Kelly Volunteer

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    That calculator isn't really used for Extruder steps per mm. It's easiest just to do a manual calibration. I use 519.2 but you could probably use 520 just fine.
     
  5. Tony Janus

    Tony Janus Member

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    I'll try your numbers when the motors come in, but I'm wondering how I would determine accuracy of the extruder. Say if I extrude 50mm of filament, would I be checking for 50mm pre hotend or 50mm post hotend, and if the latter, how would I ensure the extruded filament doesn't stretch and muddy the results? I know the process for the axis motors, but the extruder seems less intuitive to me.
     
  6. Mike Kelly

    Mike Kelly Volunteer

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    Watch this:

     
    2 people like this.
  7. Magic-Goat

    Magic-Goat Member

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    Can you advice a hobbed drive gear that will fit the 6mm shaft on the geared stepper? I'm struggling to find one, they seem to all be for 5mm
     
  8. Stargrove1

    Stargrove1 Member

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    I asked Mike the same question already, he used a Lathe to drill a 6mm hole to a 5mm drive gear.
     
  9. Magic-Goat

    Magic-Goat Member

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    Damn, i'll have to find a lathe. I think they have one at my local Hackspace. There's a lot of 5mm drive gears out there, can you recommend any or are they all pretty much the same?
     
  10. Stargrove1

    Stargrove1 Member

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    2 people like this.
  11. Magic-Goat

    Magic-Goat Member

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    Great, I'll get them ordered. Thanks!
     
  12. Mike Kelly

    Mike Kelly Volunteer

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    You can do it without a lathe. Lathing just helps keep it centered.

    To do it by hand just use more increments. Since there's a hole already the drill bit will naturally stay centered. Just slowly step up from 5mm to 6mm. Should still be perfectly centered

    There was a company that sold 6mm hobs but they unfortunately went under.
     
  13. Magic-Goat

    Magic-Goat Member

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    I think i'll be able to use the lathe, but it's good to know i have a backup plan. Thanks :)
     
  14. Tony Janus

    Tony Janus Member

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    Just uploaded a design that's compatible with the geared motors. Also includes some fixes and improvements. Tons more info on the thing I verse page.
     
  15. Tony Janus

    Tony Janus Member

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  16. Mike Kelly

    Mike Kelly Volunteer

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    Nice but damn those Hobbs are pricey
     
  17. Tony Janus

    Tony Janus Member

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    Mike, quick question for you. Looking at the board, I'm trying to figure out how to wire in these 2 geared steppers. The stepper configuration is 2B 2A 1A 1B on all connections. On the product page for the motors, it lists BLACK: A, GREEN: C, RED:B, BLUE:D. Am I to assume these are to be wired in the exact order as the current motors? Or is there a different order they need to be wired. For simplicity's sake, if you could let me know in this format, referencing the colors from the specs sheet, then I can be sure I understand:

    2B = (color)
    2A = (color)
    1A = (color)
    1B = (color)

    If the specs sheet and connections on the board correspond exactly, then I would wire them:

    2B = Black
    2A = Green
    1A = Red
    1B = Blue

    If this is indeed the case, then it's easier than I thought and I'm sorry for wasting time. But I do believe others will have the same question, and at least having the answer here will make it easier for them to find.

    ***Second question: I see D8, D9 and D10 are the 12v sources on the board. From what I've read, I'll be wiring D10 to extruder 0, D9 to extruder 1, and D8 to the heated bed. Where do I power my fans from? Do I need a seperate controller for the fans? I see something on the board next to the X stepper driver, I believe labeled D2, 12V something. Is this a possible 12v source? Or could I use one of the aux? I think this is my last hurdle before completion. Still waiting on those drive gears, but trying to figure out all my wiring now.

    ***EDIT*** And I just noticed the fans I picked up as my heatsink fans are 5v, so would I use the 5v VCC pins next to where it says "RESET S1" ? Or would I use a different 5v source.
     
    #117 Tony Janus, Dec 30, 2014
    Last edited by a moderator: Dec 30, 2014
  18. Mike Kelly

    Mike Kelly Volunteer

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    For the wires you mostly just need to make sure that they're on the same circuit. One pair goes clockwise, and the other pair goes counter clockwise. The colors you have look correct. As long as Red and Blue are a pair and green and black are a pair it will work. you might need to test it once it's in to make sure it moves the right way, if not just flip the connector over (with the power off of course)

    For controlling additional fans you need to buy something or build a mosfet circuit. I bought the RRD fan extender, or more specifically the riorand knockoff. I then need to pull in 12v for the RRD fan extender. You can also run other voltages instead depending on what you want to use since it's an isolate power circuit. If you want always on fans you just need to plug it into any 12v source. Just be aware that the polyfuse is only like 5A of supplied power and you can trip it with fans and such. Best to pull the power before the ramps and protect it with a fuse. Though I don't use fuses and temp fate.

    There is a lot of 5v pins but the 5v line is very low power. Especially with a LCD you will have issues running many other things off 5v.
     
  19. Tony Janus

    Tony Janus Member

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    Hm, well with that said now I'm wondering if I should just mount an old 500w ATX power supply and use the connections from that to power some of the fans and lights and only keep the heatsink fans running through the ramps board.
     
  20. Mike Kelly

    Mike Kelly Volunteer

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    People use ATX but you just need to make sure there's 15-20A on the 12v rail
     

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