"Orbiter" - 140g - Planetary Direct Drive Extruder

Discussion in 'Tool heads & ToolChanger' started by Joe Pomo, May 23, 2020.

  1. Joe Pomo

    Joe Pomo Well-Known Member

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    I came across this build by lorinczroby on Thingiverse, and I think it could be a good candidate for a low-mass direct drive for the tool-changer:

    https://www.thingiverse.com/thing:4223085

    They also made a remote direct drive similar to the nimble, but they say this planetary gear-box doesn't result in print artifacts resulting from high-gear ratio worm gear setups.

    See the bottom of the post for build images and videos of the extruder working.

    I'd love to hear what ya'll think!
     
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  2. blarbles

    blarbles Well-Known Member

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    For a lot less hassle you could get a Bondtech BMG with a pancake stepper motor that is 215g (75g BMG, 140g pancake). My question would be is the 77g savings worth it?
     
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  3. Jason Chodakowski

    Jason Chodakowski Active Member

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    So, there are some high speed printing vids with versions on this theme - just direct mods on the same planetary work and the extruder is capable of being a hot-plastic hose. It's very promising. Anyway, I have an Orbiter body on the way here and have already started looking for ways to get it onto my tool changer.
     
  4. Joe Pomo

    Joe Pomo Well-Known Member

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    Yeah it seems like people are having good luck with this. I designed a mount for the V6 tool and just run a PTFE tube from the extruder gears into the heatsink. The mount fastens directly to the TC "Receiver", and the orbiter body is bolted on top with two M4 screws.

    The total mass of the tool is 316g in my build. I need to test it more but the initial results are good.
     

    Attached Files:

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  5. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Hello Joe,
    Would you be willing to share your STEP files for this?
    Gene
     
  6. Joe Pomo

    Joe Pomo Well-Known Member

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    Hey Gene, I've attached the assembly - the files was too large to upload to the forum, so you can use this link:




    And for an update, the extruder is working really well. I can print faster than my Hemera tools without so much ringing. Here are some things to keep in mind, though:

    1) The motor from LDO runs hot. (I have the phase current set to ~800mA but it is still warm)
    2) Because of the motor's heat, you'll want to print your gears in nylon if possible. I used PETG gears first, but the softened and failed.
    3) When printing toward the far edge of the build plate, the x-carriage's wiring pushes on the motor enough to separate the tool plates a little and this causes audible vibration.
     
  7. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Hi Joe,

    Thanks for the files!

    I have a modification that I made if you print the gears, hub, and combined spider and drive shaft in nylon (I am using nylonX from Matterhackers. The modification changes the spider pins and spur gears so that they can be press it together after being heavily lubricated (eliminating the 3 small ball bearings). It looks like it might work out well... time will tell.

    So far, I have parts which I have stressed in a drill press ( I put the drive shaft in the chuck and run them for about 30 minutes at a slow "wood drilling" speed to break them in since the nylonX doesn't print with the highest level of detail) but have not put them into actual use yet. BTW, I was able to use a 0.4mm nozzle with the extrusion size set to 0.2 mm (in Simplify3d) and 0.1 layer height and have parts that look almost layerless. (In the photo the part on the left is in PLA-CF and the grear set and spider/drive shaft is in nylonX)

    I notice you used Version 2 of the hub housing. How do you think it works compared to versions 3 and 4 that use a heat break as a filament guide?
     

    Attached Files:

  8. Joe Pomo

    Joe Pomo Well-Known Member

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    Nice looking parts, I'd be interested to hear how your gears perform, but it sounds like they are working fine.

    I modified the hub housing to use a PTFE tube because I didn't want to sacrifice a heartbreak, and it also meant the PTFE tube could run directly from the drive gears into the V6's heatsink without any changes to the TC's V6 tool mount.
     
  9. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Hi Joe,
    Do you use 2.85 mm filament? I am trying to understand why the hub housing filament entry and exit holes are the size they are.
    Thanks!
     
  10. Joe Pomo

    Joe Pomo Well-Known Member

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    Hey, I made the holes larger to that I could add some PTFE tubing that runs from the bottom of the drive gears into the hotend. I don't think I modelled the tube in the assembly.

    You can see the white tube in the middle of the photo
     

    Attached Files:

  11. 1013D

    1013D Active Member

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    Nice, but CF filled polymer for the gears worries me. that stuff is VERY abrasive and will wear itself out. An unfilled nylon would be better for parts that rub.
     
  12. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    @Joe Pomo , have you done any further work for cable routing on this tool? I am working on mods to the Orbiter housing to include tool changer cable handling but if you have something you like I would stop work on mine; if not, I'll share mine when I think it works well enough.
     
  13. Joe Pomo

    Joe Pomo Well-Known Member

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    My cable routing was kind of a mess of zip-ties. I'm curious to see the changes you've made.
     
  14. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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  15. Joe Pomo

    Joe Pomo Well-Known Member

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  16. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Kind of brain dead cut and paste - have to try it out and if it works, I will def. get it to you
     
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  17. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    @Joe Pomo Here is the modified housing.



    I also added support for a bowden tube lock (like the kind e3d uses on the hot ends) for the guide tube input.

    Did you build yours using carbon fiber rods?
     
    #17 W1EBR.Gene, Sep 14, 2020
    Last edited: Sep 14, 2020
  18. Joe Pomo

    Joe Pomo Well-Known Member

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    Thanks for the model. I'll probably end up using your design in the future...

    I didn't have access to the CF rods so I just printed the Parts in PETG. I printed the planetary gears and the 3 pins in Nylon, but the rest of the "spider" was in PETG.
     
  19. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    The extruder gear on the drive shaft is slightly eccentric; I have to see how well it will work.
    I bought the other stepper motor originally mentioned and I think I need to have the current closer to 1200 mA to be able to run the extruder up to 60 mm/s and not drop steps... but I am still working my way through the gcode provided by e3d so I can't say for sure what the applied current is yet.
    I learned that "Formbot3d" is selling one for $100 (includes shipping from China). https://www.formbot3d.com/products/direct-drive-dual-gear-extruder-for-troodon
     
  20. Joe Pomo

    Joe Pomo Well-Known Member

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    Ah! In fact AliExpress has full kits too!

    https://www.aliexpress.com/item/100...earchweb0_0,searchweb201602_,searchweb201603_
     

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