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

  1. CapnBry

    CapnBry Well-Known
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    This is great! It looks like it definitely can be done for under $500.

    I think I spent a little over $1000 on my 12x12x12 build but I bought extras like a Smoothieboard ($190!), A/C heated bed / MIC-6 aluminum plate ($80/$40), the E3Dv6 "everything kit" ($140), RaspberryPi 2/Camera/Wifi/SD card/cables ($40/$30/$10/$8/$20) = $558. In retrospect I would just get the RAMPS and an E3Dv6 lite or an official J-Head and saved a ton of money.
     
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  2. trublu832

    trublu832 Well-Known
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    I was finally able to do my first print last night. My Cbot still desperately needs some wire management but it is functional.
    I was surprised that my first print had an error of only 20 microns without any distance calibration yet.
    Thanks Carl for the great design and everyone else for answering questions along the way!
     

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  3. Elmo Clarity

    Elmo Clarity Journeyman
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    How did you get such a nice curve of your wiring to your print head? Mine just keeps falling down.

     
  4. trublu832

    trublu832 Well-Known
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    The bundle of wires ziptied to the bowden tube help to kind of keep it in place, it still has a tendency to fall over depending where the print head goes
     
  5. Carl Feniak

    Carl Feniak Journeyman
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    Sorry John, since I don't have the right software and didn't create the step files I can't help you there. @1972 Can you help here?
     
  6. Ariel Yahni

    Ariel Yahni OpenBuilds Team
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    Hey guys, first i would like to thanks everyone for such an awesome project. Ive read every single post and learned a lot. Im going forward with this build and started ordering all items.

    Im aiming for a 16 x 16 x 24 and build the frame based on that but will start with a 12 x 12 bed since its being hard to find a large heated bed and borosilicate glass on those sizes.

    im almost done shopping everything with the exception of the controller. As i plan to have dual extruder setup i was thinking on using this one . What do you guys think? In reality i would like to use a 32 bit but could not find a suitable board with this amount of stepper driver support.
     
  7. Carl Feniak

    Carl Feniak Journeyman
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    That is giant. You'll definitely need to use some upgraded Z axis and frame rigidity modifications. That control board looks great, should work fine (realizing that you need to power the heated bed separately as that 15A circuit isn't going to cut it). Make sure you go through AK Eric's blog (linked in my printer description/front page), he has had to tackle some issues that I didn't face with my smaller bed and nozzle.
     
  8. trublu832

    trublu832 Well-Known
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  9. Carl Feniak

    Carl Feniak Journeyman
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    I was using 5mm for my attempt (see a page or two back). Basically increase retraction until you are happy with the results or start jamming. Obviously if you jam you will have to back off the amount of retraction. You can also drop your hotend temp to help with oozing.
     
  10. AK Eric

    AK Eric Journeyman
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    Yah, I've basically given up on trying to get rid of stringing with a Volcano nozzle hooked up to a Bowden system: I've sucked it up a good 20mm as a test (purely a test), and filament is still left in the nozzle enough to ooze out. My current thought process is: You want good quality Volcano? Best go direct-drive.
     
  11. Carl Feniak

    Carl Feniak Journeyman
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    Alright, who wants to design a light single nozzle direct drive extruder carriage?
     
  12. Carl Feniak

    Carl Feniak Journeyman
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    Do I have a guinea pig?
    Capture.JPG
     
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  13. Elmo Clarity

    Elmo Clarity Journeyman
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    Do a dual version and I'll test it out. :)
     
  14. Carl Feniak

    Carl Feniak Journeyman
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    I am concerned about the moving mass of two stepper motors. Sharp corners and other large acceleration/decelerations will create a lot of vibration and cause ghosting. You'd really have to clamp down on those limits.
     
  15. AK Eric

    AK Eric Journeyman
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    Not sure when I can get to it, but I'd totally try that out ;)
     
  16. Carl Feniak

    Carl Feniak Journeyman
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    Here ya go. Beta version, please provide recommendations on changes and note any fitment issues. I have not used or even printed this.
    It is meant to be used with a bowden tube to guide the filament to the carriage and a short length of tube to guide it down to the nozzle from the direct drive extruder.
     

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  17. AK Eric

    AK Eric Journeyman
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    Awesome. I'll get this on the todo. Since I have a spare stepper laying around this should be pretty plug-n-play...
     
  18. Ariel Yahni

    Ariel Yahni OpenBuilds Team
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    Guys would there be a way to bake the bed stay at the bottom? What would be needed? Or is it impossible with in Core XY
     
  19. Carl Feniak

    Carl Feniak Journeyman
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    What do you mean? Have it move there at the end of a print? If so, yes. Just add some custom gcode in slic3r to the "End G-Code" section.

    Something like:
    G90 ; Switch to absolute coordinates, should already be there though
    G1 Z200 F1000 ; Linear move to program Z=200mm at a speed of 1000mm/min

    Where in this example your lowest bed position is 200mm from origin.
    At a speed of 1000mm/min it will take 1/5th of a minute to go from origin to max Z position.
     
  20. souprmage

    souprmage New
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    I think he's asking to keep the bed stationary in the Z-axis and have the head move. But that defeats the purpose of CoreXY I believe.
     
  21. Carl Feniak

    Carl Feniak Journeyman
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    If you are thinking of not moving the bed at all then you must get your Z movement by either:
    Moving the hotend up and down like this:
    Maximus 3D Printer | OpenBuilds
    Or moving the entire Z assembly up and down like this:
    CoreXY W/ Fixed Build Plate & Enclosure | OpenBuilds
    Or some other inventive means.

    I don't prefer the first as it makes the carriage assembly very heavy for a coreXY belt system, it is better suited for a heavy lead screw/ball screw driven CNC with a heavy tool assembly.
    The second is just much more complicated and I don't see any benefit from adding that complexity (though neat).
    If you really don't want a moving bed then a delta printer is hands down the way to go.
    I would do something similar to this but redesign it to use my 3D printer plate system instead of aluminum ones and use a 10" or 12" round bed.
    Delta-Six | OpenBuilds

    Personally I don't have an issue with it moving in the Z direction as it only moves once per layer. Even if you have nozzle lift enabled then it only moves slightly. Much better than a constantly moving Y axis bed which deals with large inertial direction changes.
    If it is a cantilevered bed like mine then it has to be rigid enough to handle the forces. As folks have exceeded my original 8" canteliver, improvements were necessary.

    These came in the form of two solutions:
    1) spread the forces over a large distance. The rear moving Z bar was changed from 20x40 to 20x60 extrusion. Could even go to 20x80 but it also impacts usable Z height. The bars supporting the bed can be upgraded as well. Additionally I have seen the brackets holding these together be beefed up.
    2) move the motors from the very back to the 1/4 or 1/3 closer. Uses an extra piece of extrusion but all the same parts.
     
  22. AK Eric

    AK Eric Journeyman
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    @trublu832 : You willing to share that x-gantry rear fan holder? I'm looking at redoing some of that, and your design would save me a lot of time
     
  23. trublu832

    trublu832 Well-Known
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    No problem, all of the parts for my printer are posted here: D-Bot by spauda01
     
  24. AK Eric

    AK Eric Journeyman
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    Awesome, thanks!
     
  25. AK Eric

    AK Eric Journeyman
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    Hey C-Bot community: This afternoon I decided to rearrange my dual-rear-leadscrews into a front\rear leadscrew setup. I've been thinking about going triple-leadscrew, but that would require the purchasing of more\new hardware. Figured I'd give this a shot since it really doesn't take anything extra, than a spare cutoff piece of v-slot I ran across the front of the build platform.
    I've just started using it, it seems super stable compared to the regular (front unsupported) cantilevered bed. Can anyone come up with why this would be a bad idea? In my head this is a 'good thing' since the bed now has stability on two perpendicular axes. But I welcome any comments.
    leadscrew_rearranged.jpg
     
  26. trublu832

    trublu832 Well-Known
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    This is essentially what I did but I set up a lead screw on either side, takes all of the torque off of the wheel assemblies and avoids the diving board effect.
     
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  27. Carl Feniak

    Carl Feniak Journeyman
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    @AK Eric Have you given it a try yet? The only issue I see is a risk of left/right stability. The V wheels may be enough though. I like that you added a cross piece on the bed frame, I actually had that my original design (though at the midpoint), but forgot to actually install it.
    I like the way @trublu832 modified it slightly better as it reduces the canteliver but still stabilizes left/right. It costs a piece of extrusion, but it also allows easy adjustment on that bar to align with the bed frame.
     
  28. AK Eric

    AK Eric Journeyman
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    I just did a 6" tall vase, didn't see any issues with the print, so, so far so good. But if I see any negative effects I'll post up.
    FYI, printing out the new direct drive bits right now....
     
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  29. CapnBry

    CapnBry Well-Known
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    I have a E3D Volcano as well I run with the 0.6mm nozzle and 0.24mm layer height at 60mm/s. My retraction settings are like this on my 300x300 C-Bot
    Code:
    M207 S7.5 F3900 Z0.2 ; retraction
    M208 S0.2 F1500 ; retraction recovery
    
    This gives me no stringing but it does leave a little dollup of plastic on the egress which is not great because I have to file them down to make pieces fit together. It was on my TODO list to make a direct drive XY carriage with the motor turned sideways to limit the distance to the E3D (like this) but hadn't been able to imagine how to keep the motor out of the way of the belt adjustments. I will definitely have to try your design Carl!
     
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  30. Carl Feniak

    Carl Feniak Journeyman
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    I think the little dollup you are seeing is from the nozzle lift movement. I had the same, but it does help clear the print during nozzle movements and with oozing.
    Hopefully @AK Eric will have some time to test and debug the design soon ;) Feel free to help him out though!
     

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