C-Bot 3D Printer: Resource Page

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This page is a collection of resource for building my Core-XY C-Bot printer:  Electronics, hardware, software related.

Finished C-Bot!

Finished C-Bot!

OpenBuilds Links:

  • Main C-Bot page : Includes printed part picture links, and external 3d files that are needed (for the Bowden extruder, etc).
  • C-Bot Forum : Fantastic Resource
  • C-Bot File List : Original BOM, assembly guide, and all the stl’s to print.
  • Link to my BOM.  This is a modified version from the OpenBuilds page based on my specific needs.
    • Note when ordering the hardware:  Think about the overall color of the printer:  Many nuts and bolts can come in silver or black:  Do you care? Should they all be one or the other?  Worth considering.

Hardware:

Core-XY Mechanics Theory Link

To build the 12″ x12″ x24″ build volume, these were my extrusions lengths:

  • The below labeling corresponds with the Assembly Guide updates (above link) that Mason Sheffield made.
  • 20×40 OpenBuilds V-Slot Extrusions:
    • A : Vertical Legs : 4x 820mm
    • B : Top/Bottom Horizontal X : x4 440mm
    • C : Top Horizontal Y : 2x 450mm
    • D : Base Horizontal Y : 2x 420mm
    • E : Print Bed Supports (Mounts to G) : 2x 395mm
    • F : Top XY-Gantry (what extruder mounts to) : x1 464mm
  • 20×60 OpenBuilds V-Slot Extrusions:
    • G : Rear Z-Slider : x1 428mm
  • ACME Leadscrews : 2x 705mm

Important notes though:

  • Using the E3D Volcano Extruder subtracts 2″ from your build height based on how much it hangs down.  And, the above calculates on the Z-axis were still off, so right now I’m at a practical 21″ build height not 24″.  To resolve a few options:
    • Cut longer A lengths.
    • Redesign the extruder holder to move it ‘up’ more.
    • Since my z-gantry is a 40×60, I could actually move the whole build-platform down by 20mm by sort of ‘reversing’ it.  however, I feel that design would give less overall strength to it.
  • Basically, calculate your extruder length into your overall height.

Electronics


Software/Firmware


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Building the C-Bot 3D printer: Part 26 : First 'big' print
Building the C-Bot 3D printer: Part 27 : First ‘really big’ print
    • Pete Parise
    • July 22nd, 2015 9:44am

    Hi Eric,
    I wanted to touch base with you regarding your experience with the new bot.
    How is it handling the height? Is it stable enough? I’m also shooting for a larger volume
    (about 12x12x24), but wanted to see if you’re finding any issues with the height of the printer.
    Do you find the 90 deg corner braces sufficient?

    This will be my first 3D printer build, so I expect it will be challenging.
    I suppose I can always shorten the verticals if there’s a problem.

    Thanks again for the blog!

  1. Hey Pete, be happy to answer your questions:

    Height: So far so good. I just printed out something 20″ tall, I’ll be blogging about it soon, but it handled it no problem. Like mentioned above, while I spec’d my printer to have a 24″ build height, it’s really around 21″, so you should account for that if you want a true 24″. Seems rigid enough, 90deg corners seem fine so far.
    Note at that height, there’s a lot of moving mass up high, so there is a bit of shake up there when the toolhead is moving fast: Physically clamping the machine down to a solid countertop would probably resolve this, but I haven’t done that yet.

    I’ll probably eventually look into a tripple-leadscrew design just to help reduce bounce on the build platform. Not that it’s so bad now, but it could always be better 😉

    Good luck on your build!

    • eve tan
    • July 30th, 2015 10:50pm

    Hi Eric,

    would you mind to show me more photo of your success print? as i’m very interested to try out your format in making one of my own. please advise!

    • eve tan
    • July 30th, 2015 10:51pm

    can i know whether the STL print part use in C bot also can be use for this big baby? do i need to change any things inside?

  2. Eve: I’m mainly still in the calibration phase. The only pics of prints I’ve made are on this one post: http://www.akeric.com/blog/?p=3300
    Printing with the Volcano requires me to basically relearn everything when it comes to tuning the print settings.

    For your second question, I don’t understand your wording, sorry.

    • eve tan
    • August 3rd, 2015 7:10pm

    sorry just to make myself clear,
    First do you have any other finishing print photo that are print with C Bot?
    Second can we use any other motherboard that are comparable with repetier?

    • Pete Parise
    • August 5th, 2015 11:17am

    Hi Eric!

    I’m about to commit my aluminum to the chop saw and wanted to double check my math. When I calculate the length for the “C : Top Horizontal Y” length, I come up with 440mm rather than 450mm. I base this on the 420mm base Y plus the front vertical leg (20mm). The back side of the Top horizontal Y piece is flush with the front face of the back vertical leg. I’m also basing this on the stl files for the rear Idlers and XY motor mounts. Is this correct or am I missing 10mm somewhere? Have the idlers or motor mounts been updated from the originals? Thanks again for your help.

  3. Pete: I can’t comment directly on the math unfortunately (nor can I measure right now, not near printer): i just based mine on my buddies 12x12x12″, and lengthened the verticals to make it 24″ tall (but like I’ve mentioned in posts it really ended up being around 21″).
    That being said, all the values I list worked fine for me, based on the stl files provided.
    If you cut long you can cut it shorter if needed… but it’s hard to go the other way 😉

  4. Eve: no other pics right now, but hopefully more soon.
    As far as the hardware, anything that supports corexy mechanics should work.

    • Pete Parise
    • August 5th, 2015 2:29pm

    @AKeric
    Perfect! Cover me! I’m goin’ in! :)

  5. Hi Eric,

    So I built a custom version of your design. Had to reinforce the frame more but it worked out nicely.
    My only flaws it seems is thst for one, my belts wont move. Not sure what the deal is but there nt moving no matter the tension or lack there of when I adjust em. Any ideas?

    Next I seem to have run into a snafu with my nema 17s. Seems there turning really slow and I am at a loss. I checked my settings on repiter and arduino but maybe I have em set to low. Power is good and I’m at a loss.

  6. When you say your belts won’t move: They won’t move… how?
    * When the power is off and you try to manually slide them back and forth: They should move freely. If not, I’d check all the tension points: do all the idler bearings spin freely when there is no belt? Is the belt rubbing on anything in the v-slot?
    * When the power to the machine is on, and the steppers are engaged: They shouldn’t move.
    * When the power to the machine is on, but the steppers are disengaged: They should move freely.

    Nema17 issues: My guesses include:
    * You didn’t tune their driver voltages correctly.
    * They’re wired incorrectly.
    * Do they all behave weird, or just one? If just one, then I’d guess possibly a break in one of the wires.

    Let me know how it goes.

  7. When I say the belts wont move. The belts refuse to move the position of the extruder. The belts also get stuck at some point and the entire thing won’t move. Even with the power off it takes a good amount of force to move the parts.

    The motors are running fine. They came off anot her 3d printer thst was running smoothly. Everything is wired perfectly too. I triple checked it all.

    The belts seem to be my biggest issues and I don’t know why. I’ve tightened, lossneed and to no avail. It’s rather frustrating. Yet so far this is how it seems to go. Mind you my design off of yours is 1500mm length, 750mm width and 1000mm height. That’s all I changed was the size. I followed the original c bot on open builders since his and your design are pretty much the same.

  8. The y-axis gantry : Does it roll smoothly all the way front to back across the top with just the push of a finger: Like you give it a push, and it sails all the way across the top and bonks into the back? Same of the x-axis\hotend: Does it easily roll left\right? They should both have zero (or very light) resistance all the way across their travel. If they bind at any point, this will totally mess things up. You’re dimensions sound huuuuuge. Which is cool, but the bigger you go the harder it is to square everything. My guess based on the symptoms you’re describing is that it’s not square, and you’er getting binding on your x\y gantries. I had to do a lot of loosening, squaring, tightening, repeat,… to get mine working correctly.
    Also, on a side note: For a bed platform that big, did you stick with the dual-rear-leadscrew design, or modify it to a triple-leadscrew? For a bed that size, I could see a bit of sag happening as the print weight increases, not to mention residual vibration effecting it. One of my eventual upgrades will be to add a 3rd leadscrew to mine.

  9. Well to give you a wondrous laugh. Both my x and y with belts on do not move with the push of a finger as you call it.

    With the belts off they do that quite easily and glide like a figure skater in the Olympics.

    As for my print bed, I have used 2 z motors one opposite of the other. It lifts a good amount a weight just fine so far. My z isn’t the issue as the bed is squared off and has support wheels on both sides instead of the 1. My plan is to eventually add 2 more screws to this so it’s stable from the middle of all sides.

    I would like to discuss this in a more real tomw chat if you would good sir. As we both seem t be dealing with snail board comments lol

  10. I’d be happy to discuss it more, but I’m not sure what other help I can actually provide: if all your gantries move freely, it makes no sense to me why your getting binding. I’d recommend you post this issue to the cbot forum, since you’ll get a lot more knowledgeable eyes on it than just mine. We’re obviously both missing something.

  11. I’ve discovered the issue. Fml it was a pain to figure but it seems the belt doesn’t have enough space between the parts and the bearings to move the extruder. Seems I need to do some minor drill and sanding to get enough room. The rest is fine. Just the bar itself that has issues on both ends for the bearings. I had to play around with it for a while to figure this out.

    If this fix doesn’t work then I will post in the main forum but I do thank you for your help in process of elimination, now I know I ain’t going nuts lol

  12. Interesting, glad you found it. Weird though: My belts\bearings (I presume you mean the idler bearings?) have plenty of play and no binding (one of the few things I didn’t have to adjust). Is it the belt not fitting in the idler, or the idler not fitting in the printed bracket? I’m wondering if you maybe built the idlers wrong, there’s an extra washer that goes in the middle of the operation that acts as a spacer, so the belt doesn’t bind in the idler (that’s in the docs though, so I presume you did that). Well, at least you can move forward.

  13. Eric,

    Yea the spacer is between the bearings. It’s just getting caught between the bearing and the printed part. Yet I know how to fix that lol

    • Ariel Yahni
    • October 21st, 2015 4:38am

    Eric

    Hi, first let me tell you what a great project and what a good friend you have. I’ve being looking for sometime now to buy a large printer. I was considering very seriurosly buying the gcreate since I wanted a big build volume and stumbled to your project.

    I have a few questions:
    – Is the BOM up to date, I read you made some changes just want to make sure. I live in Panama and I have to order everything from the US just one to make sure I order everything.
    – Why use a Bowden extruded and not a direct drive? Is it because of the increased weight that would healed a slower performance? Have you tried flexible filament?
    – what should I change if I want XY to be 16″?
    – Did your good friend Mason share the printed parts? I don’t seem to find them

    Again I want to thank you and your friend for sharing such a great project

    Thanks

  14. @Ariel Yahni:
    * BOM : Up to date, the only change (I recall) is I’ve upgraded my cooling fans, which you can find into to in my blog.
    * I used the Bowden since that’s how the designs were spec’d for the C-Bot over on the OpenBuilds page (the instructions I followed). No reason other than that: I didn’t want to delta too much from the design on my first printer build. Nothing wrong with a direct drive system, in fact I like it quite a bit more, especially if you’re going to go the volcano route.
    * To increase the XY size: since my build was based on a 12″ square build platform, just add 4″ to all the XY extrusion lengths (top horizontals, bottom horizontals, rear build plate horizontal).
    * Mason did share the updated parts on the openBuilds wiki forum page. You can probably just search through his posts.
    * Note: If you’re increasing the build platform size that large, the cantilevered bed won’t work with just two rear leadscrews: You’ll really need to upgrade to a triple-leadscrew design with an extra one in the front to help with sag and vibration.

    Panama is beautiful! I took a cruise through the canal a few years back and toured Panama city. What a great place.

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