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Discussion in '3D printers' started by Carl Feniak, Sep 29, 2014.

  1. Carl Feniak

    Carl Feniak Journeyman
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    Please do. Any reason not to just use a regular mechanical switch? Something like this:
    4 x Mechanical Endstop For 3D Printer XYZ Axis ( Mech limit switch )
    Maybe there is software debounce?
     
  2. Joseph Ecker

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    Hi Carl,

    Yeah, I could probably get away with a simple mechanical switch, but I already bought all these mightyboard endstop switches, so might as well use them :)

    I actually have two versions of the bracket. The first one works with the original back-X plate, and the second one works with the new direct drive back-X plate.

    Here are some pictures of the endstop modification and the old/new brackets, along with the bracket STLs.

    The new bracket needs to be modified to shift the fan mounting pillars to the left enough for an M3 nut to secure the fan hinge.

    And, yes, those are "rivets" :) I didn't have any really tiny screws to secure the switch, but the rivets fit perfectly... lol
     

    Attached Files:

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  3. Elmo Clarity

    Elmo Clarity Journeyman
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    In the message with the V2 files for the direct extruder, there are a couple other files for a fan duct and mount. I printed those up and attached it and it looks like it might be too low for my E3D v6 hot end. Has anyone else tried this with the v6?
     
  4. Ariel Yahni

    Ariel Yahni OpenBuilds Team
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    Hey guys, im really exited with my build progress and would love to be up to date testing the new direct drive but i just finished assembling the printer. Now im stuck on the firmware. Can anyone point me to a really "for dummies" step by step on it? I got a megatronics v2 board just dont know where to start.

    Any help appreciated
     
  5. Carl Feniak

    Carl Feniak Journeyman
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    What firmware are you putting on it?
     
  6. Ariel Yahni

    Ariel Yahni OpenBuilds Team
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    I believe Marlin would be the best option.
     
  7. trublu832

    trublu832 Well-Known
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  8. Ariel Yahni

    Ariel Yahni OpenBuilds Team
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    Thanks Solid Utopia should be what I'm looking for. Can anyone share a Marlin file just for reference please.
     
  9. Balu

    Balu Well-Known
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    Finally, I got through all the pages. Phew.

    Quick question that just came to my head while helping a friend build a Prusa I3 derivative: Besides the obvious reason of being able to "hide" the belts in this build, what are the advantages of using V-Slot and wheels instead of rods with linear bearings like most other builds?

    Rods + bearings seem to be cheaper, easier to put together and require less adjustments?
     
  10. Carl Feniak

    Carl Feniak Journeyman
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    Another bonus is that V-slot doubles as both the frame of the printer and the linear guide for motion which reduces parts and complexity. The derlin wheels run more quietly then the metal on metal contact of the hardened rod and linear bearings of my OB1.4 (similar to the prusa).
    The wheels are very easy to adjust... but they do require that you true up the frame very well since the v slot bars need to be parallel to each other. This is what can be difficult.
     
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  11. Joseph Ecker

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    The reason most important for me about using V-Slot over rods is flex. Your print quality will not be as good if you use rods. There are many discussions over on the google groups 3D Printer Tips and Tricks about rods versus extrusion.
     
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  12. adamcooks

    adamcooks Well-Known
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    Round unsupported rods lose rigidity on longer spans. A 20x40 in the c-bot's orientation is much stiffer and probably good for .75M to 1M gantry. I bet you would need 25mm or so round rod to span a meter, who knows what that would weigh.
     
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  13. Balu

    Balu Well-Known
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    Thanks for the quick replies guys. Guess it helps to stay up late at night in a totally different timezone ;).

    There have been a few remixes to this design for different sizes, but also belt layouts, etc. Since you have your version running for more than a year now, Carl - are there things you'd change from your original design?
     
  14. Carl Feniak

    Carl Feniak Journeyman
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    Hmm, I haven't seen any remixes on the XY belt layout so you'd have to point me to those for comment. One thing I have noted is an extension of the XY blocks that would be a good idea and very easy to do:
    http://thingiverse-production-new.s...7e/Right_Rear_Idler_RevB_preview_featured.jpg note: this is from the D-bot build
    They wouldn't work for me though as it would interfere with my endstop mounting.

    I may try the direct extruder setup so that I can print softer/more flexible filaments, but for a typical 0.4mm nozzle I have the bowden setup working quite well. If you want to go to a volcano hotend (a high volume flow nozzle good for large prints) then it seems like those users are switching over to the direct feed due to stringing issues.
    The fan shrouds I designed should be made more rigid as they can vibrate a lot while doing quick gap fill movements, so I am not happy with them. The D-bot, linked below, has an alternative fan option that looks good, but I do like having two fans (one on each side of the print nozzle).

    For my bed size of 8" x 12" I am happy with my Z axis, but would recommend an upgrade if going 12" x 12". I would use 20x60 extrusion for the heated bed frame with all of them unless you are using 3 lead screws.
    There are currently 3 good remix options on this front:
    3 Lead screws:
    Triple C-Bot | OpenBuilds
    Offset lead screws:
    D-Bot by spauda01
    Front back lead screws:
    Building the C-Bot 3D printer: Part 29 : Rearranging the Leadscrews

    I have seen different approaches on endstop setup, but I like my static ones. I've had no issues with them, but all the remixes seem like they'd be good as well.

    I mentioned designing angular braces a few pages back but no one bit on the idea so I didn't bother designing them. I still thing these would be a great way to stiffen up the larger builds and provide good places to mount your filament roll off of (same place as it is now but with a smaller plastic piece).
     
    #1154 Carl Feniak, Nov 12, 2015
    Last edited: Nov 12, 2015
  15. Balu

    Balu Well-Known
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    Oh sorry. I meant "belt layouts" mainly for the Z axis to avoid multiple steppers.

    As for the endstops - I always wonder why people have them on the moving parts when there's a perfect static place on the other side.
     
  16. Carl Feniak

    Carl Feniak Journeyman
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    Oh yeah, someone remixed the LCD stand. This is a good idea becasue if you leave the LCD tilted and the print is tall then the bed can come down and hit it!
     
  17. Joseph Ecker

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    I think the main reason for putting the X endstop on the moving piece is to reduce the number of wire runs back to the controller board.
     
  18. Ariel Yahni

    Ariel Yahni OpenBuilds Team
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    @AK Eric would you share your firmware file? I have the exact same setup and need to compare while a learn from it.
     
  19. trublu832

    trublu832 Well-Known
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    I preferred to put my X endstop on the print carriage so that the printer can always home each axis independently and it can always do the default homing of X-> Y-> Z.

    If you put the X endstop on the side then you have to flip X and Y orientation and always home 'X' before 'Y'

    Putting the endstop on the print carriage adds an insignificant amount of mass compared to the aluminum H bar and hot end.

    Just a preference and like everything on this great design, it's all customizable.

    [​IMG]
     
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  20. AK Eric

    AK Eric Journeyman
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    Not at all: I presume you mean my Configuration.h and Configuration_adv.h? Find attached
     

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  21. trublu832

    trublu832 Well-Known
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    I think your message got buried earlier.
    I believe this is the fan duct I remixed and put on my Cbot.
    I'm using it with an E3D v6 and it all fits, let me know if you need help.
     
  22. TruculentMC

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    Thanks for the design. I'm currently sourcing parts for a 12" cube, but after that I would like to build another that's at least 24x24" build size in XY. Has anyone else built one this large that can share their experiences?

    Also, do the current set of STLs reflect all the mods and feedback from this thread? I read through all 40 pages but it's a little unwieldy and difficult to keep track of what's changed for the better or worse.
     
  23. trublu832

    trublu832 Well-Known
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    @AK Eric built the biggest version of this printer that I have seen
    Building the C-Bot 3D printer: Part 1
     
  24. Carl Feniak

    Carl Feniak Journeyman
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    Hmm, that is a good question. I'd say they are up to date, but some modifications are located at the remix locations (see post a page earlier for links). Those include things like endstop holder locations and Adams motor mounts for the 3 lead screw option. Also, the direct feed extruder is not included in that zip file. Someone was looking to build 16"x16" but it isn't complete yet. I've also come across a 3' tall version on a google forum.
    Definitely needs a Z axis modification (probably 3 lead screw would be best for that large a bed) and physical improvement of corner brackets to increase the frame rigidity.
     
  25. TruculentMC

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    Thanks for the replies - yes, I was considering the 3-screw Z-axis, probably with a NEMA23 motor. I was considering a 3rd vertical for the Z axis as well to stiffen it -- is it better to have the screws near to the Z-axis linear rails or further away? Not sure if the bigger motor would be useful on XY axes as well. I'll probably increase the XY rails to 20x60 and I'm planning to enclose the printer as well -- probably with dibond panels, which should add quite a bit to rigidity. I'm a bit worried about noise from resonance but I think it should be manageable.
     
  26. Joseph Ecker

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    Has anyone seen vertical lines like this before?

    Does it have to do with the idler bearings and GT2 belt patch? I know there are parts of the X and Y belt path where the GT2 belt has teeth facing the idlers... is the belt supposed to twist 180 so that the flat part faces the idlers?

    Thanks in advance for any help, as this is driving me up a wall

    (BTW, I do see the traditional ringing that follows left-side edges, and think I know how to fix that. I'm most concerned with the consistently vertical lines)
     

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  27. Joseph Ecker

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    I think I resolved the vertical lines with adding a 180 degree twist in the long-run side of each of the X and Y belts as they leave the X/Y steppers...
     

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  28. Joseph Ecker

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    Here are my endstop brackets.... X is on the direct-drive extruder carriage. I'm also attaching a modified carriage front that can be used with a hexagon hotend.
     

    Attached Files:

  29. Carl Feniak

    Carl Feniak Journeyman
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    Thanks for sharing, what did you need to change for the hexagon hotend? Groove mount slightly different dimensions?
     
  30. Joseph Ecker

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    Yes, I shrunk the lip on the groove mount from 5.6 to 4.6mm.
     

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