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D-Bot Core-XY 3D Printer

by spauda01, published

D-Bot Core-XY 3D Printer by spauda01 Sep 6, 2015
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Summary

Remix of the Core-XY C-Bot.

300mm x 200mm x 325mm print volume

$550 approximate cost

Read the build guide before ordering parts.

Larger cover photo: http://i.imgur.com/oFbBbEb.jpg

Example prints made with the D-Bot: http://www.thingiverse.com/spauda01/makes

Demo Videos: https://www.youtube.com/playlist?list=PLtTX7qAE76Mwo2uvCK9YH6KMR-vQdPqly

All credit for the original C-Bot design goes to cfeniak.
Thanks to those who contributed at http://www.openbuilds.com/threads/c-bot.726/

Optional Components

Ramps 1.4 Enclosure - http://www.thingiverse.com/thing:1352320
Cable Chain - http://www.thingiverse.com/thing:1167746
Vslot Endcaps - http://www.thingiverse.com/thing:398515
Tubing Clips - http://www.thingiverse.com/thing:1232213
Bowden retraction stabilizer - http://www.thingiverse.com/thing:936611
Extruder Manual Feed Knob (small) - http://www.thingiverse.com/thing:474394
Vslot Channel Cover - http://www.thingiverse.com/thing:832077

D-Bot and C-Bot Differences

1) The lead screws and Z motors were moved forward to better lift the print bed from its center of gravity rather than use a fully cantilevered print bed.
2) Increased printable Z height to 330mm (~13")
3) Use of 20mm rails for the bottom sections to save cost and reduce bulk.
4) Various adjustments of printable parts, either to add plastic where it seemed like more rigidity was needed or to subtract plastic where it was not needed.
5) Accessories such as a simplified spool holder a cable chain for bed wiring
6) Relocated endstop mounting to maximize Y travel and utilize default homing scheme.
7) Overall reduction in cost compared to the original bill of materials (2$ square nuts vs 40$ Tnuts, etc.)

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Curious if anyone with a D-Bot/C-Bot try dual direct drive with expanded carriage or some other modification? Concerned about the added weight on the carriage / v wheels, and added stress to the belts / steppers.

Maybe a titan extruder with two pancake style steppers

Ya I had looked at doing Nema 14s or even the geared ones, althought the short stack Nema 17s I found aren't much heavier than the 14s.

Have considered widening the carriage and placing them on top of it with the shafts facing the front. Or having them face each other and be directly above the chimera, but the weight might be the issue here. Honestly would love to design it as a straight conversion using just the 4 holes from the extruder mount and the two holes from the guide mount, maybe having part of it just rest on the top of the carriage.

I'm thinking of modifying https://www.youmagine.com/designs/modicum-extruder-v1 - it would be a thing of beauty.

I just realized I will lose some extrusion by doing the cuts with the mitre saw (3.2mm per cut). If I reduce the size of the 4 pillars from 520mm to 515mm, would that be ok or will cause any problems?

Blade kerf was already accounted for in the cut diagram

Started printing a few parts and it looks like all my holes are going to be too undersized to fit any bolt through. Will investigate some print setting tweaks but otherwise I guess I will be running a drill through my parts.. just hoping this doesn't affect the accuracy of the parts.

powis - in reply to powis

Having good results with Cura vs Slic3r.. I am running a slower speed overall so it is hard to say it was all the software.. rather than the settings.

Would solid core cat5e wire work for the stepper motors in this design since the motors are stationary? I know I have read, if using Cat5 for the steppers at all you should use stranded but I think that was mainly for strain issues in designs with motors that moved. I have a ton of that stuff laying around so I was thinking of using it for this build.

3 days ago - Modified 3 days ago
beepbeep - in reply to 3DExtruded

As the wires are 24AWG they can comfortably handle 3.5 amps and the twisted pairs can only be of benefit (assuming the capacitance is not an issue). I like to use cat 5 where I can as similarly I bought a 1000 ft box of it years ago - it makes great speaker cable! My overengineering mentality forbids me to use it for steppers, but I've seen it done frequently by people who really know their stuff without any issues. I try to use it for thermistor wiring where possible.

Thanks for your reply -- I really appreciate it. My biggest concern was about the fact that they were solid core. I think that it will still be ok, as in this application the motors aren't moving. I realize why most people wouldn't use solid core wire for 3D printers in places where the wires need to move a lot but in this application I wanted to make sure that didn't apply.

It will be harder to put into crimp terminals compared to stranded wire, might even break off when you try to crimp on a terminal

Thanks for the response, and for sharing your great work with the community!

Question on upright heights for the z-pillars. I'm going to be using 540mm lead screws from opensource - and it seems quite critical that I get the upright pillar length accurate.

The build guide shows 520mm for the 400mm lead screws, but the C-Bot Cut Calculator (https://mysterious-inlet-87122.herokuapp.com/) would have us cut those at 550mm for a 400mm lead screw.

For a 540 lead screw - the Cut Calc calls for a 590mm cut, but if I add 140mm to the guides' 520mm .. it would be 660mm.

I don't want to cut to long (or it seems my nozzles will be to high) .. or to short and lose build height.

Also - I'm going to be using E3D's chimera/cyclops hot ends, and they seem to be a bit shorter than the E3D v6.

I finally have all my pieces and ready to start cutting - but, I see this as a critical measurement.

5 days ago - Modified 5 days ago
beepbeep - in reply to goldentuna1200

The build guide is right for the 400mm lead screw. Add your difference onto the rail heights and get cutting, you will be fine.

With regards to the chimera - it depends how your carriage is laid out, you will want the positioning to be similar to that of the standard V6 to keep the heat away from the printed carriage. In doing this the nozzles should end up very close (within 10mm) of the V6 position. As the lead screws have approx 30mm extra when homed, you will still have 20mm or so to play with.

Good luck with your build!

thanks so much for your info

No worries, I'm about to start a similar build myself - 600mm lead screws with a chimera.

If you want to deviate from the build guide and you are concerned about getting heights just right you should model up the frame and parts in sketchup, autocad, etc and verify everything fits.

I don't really have access to software like those mentioned ... I guess I can try to do a wood model first.

sketchup is free and there is a sketchup model of the printer on the downloads page

ah... each time I've looked at sketchup I thought it was $695 .... I guess that's the Pro version - I just looked again and am downloading - thanks.

No way I'd recommend a program like that, free all the way!

I printed all parts from PetG 100% infill, 0.2 layer height, 4 top and bottom layers and 4 perimeters at 240 degrees print temperature. Mounting parts cracks when i screw to the frame!!! What happens? All parts must be reprint from ABS. Can you help me? What parameters use to print new parts from ABS? Sorry for my english.

Be sure to drill all holes out to the correct diameter before forcing screws through them as this can be a problem too.

Firstly, never print with 100% infill, its not needed, bad practice to use over 60% but I've used up to 90% without issue.

Secondly, you must be tightening things up very tightly if you are cracking PETG. Only part I managed to crack (mines all PETG 90%), was the rear plate for the belt holder. I've since replaced it since I'm using a different carriage but havent cracked that one though.

PETG is fine, just dont over tighten the bolts.

Jul 16, 2016 - Modified Jul 16, 2016

To anyone who's thinking about buying hammer nuts from banggood, I wouldn't. More than half of them were misshapen and you'd probably be better off with square nuts from mrmetric. I ended up paying $13 for maybe, maybe, 80 acceptable nuts, in which case it's better just go with Misumi T-nuts for the best quality.. Too bad they don't make the square nuts a little wider for better contact with the slots.

KDan - in reply to geoxile

I've had no major problems with drop in T-nuts from Banggood, AliExpress or other Chinese suppliers like RobotDigg.. All of the drop in, quarter turn, hammer style T-nuts I've bought have a variability in the height of the neck area that protrudes into the slot area. This can cause a problem with parts that have raised channels to engage in the slot - sometimes the tnuts bottom out. I've been using them for several years and I realized early on that parts needed to be modeled with a sufficient relief area around the hole for the t-nut to accommodate this. Most pre-assembly t-nuts have this neck area also, and can't be used with raised channels on the printed parts without risk of bottoming before engaging the extrusion.

Personally, I prefer to use the quarter-turn tnuts in all of my aluminum extrusion builds. They don't stick or jam into the extrusion like square nuts can. They are simply more versatile and make assembly much faster. The only real issue with them is that you sometimes can't tell if they have turned and engaged when tightening because there is almost no "feel". I've mostly solved that problem by applying a small spot of blue Loctite or Vibra-Tite VC-3 (better choice) to the tip of the threads. This provides lots of drag so you can feel when the nut turns and engages in the extrusion. In a pinch, standard silicone sealant on the threads can also work well.

4 days ago - Modified 4 days ago
beepbeep - in reply to kabar03

I got a couple of packs of these. I wouldn't trust them for the main frame assembly (not enough surface area in contact with the rails for me), but they are fantastic for attaching things like spool holders, ramps box, the power switch holder, or any accessories you want to fit after the fact.

You can get M5 square nuts in different sizes. I have some which will pop in and out of the extrusion and some which totally wedge in there... I use the larger ones for the frame assembly, though they are fiddly to get in as it's such a tight fit.

The square nuts are a little more narrow than T nuts but the benefit is that they can usually be put into the slot after the frame is assembled

The T-nuts are drop in, not even a tapping needed.

NEWBIE ALERT :(
Im new to 3D printing - very new - I find it fascinating and have spent the day (almost) browsing thingiverse.
I would like to print this unit out which seems straight forward.
However, can anyone pointing me to where I can order all the hardware?

spauda01 has provided links in the BoM.

Jul 16, 2016 - Modified Jul 17, 2016

Oh yeah also kinda adding to lesterljw's question, also any guide on doing a 300x300 bed?
-edit nvm its in the PDF at the appendix.

HI,
Thanks for your effort to have this nice design and setup and putting all the info together. I am planning to build a D-Bot now but thinking to go for 400x300 bed, about the V-slot rails length am i just have to based on the 300mm length + additional 100mm?

still waiting on all my ordered parts from china.
anyone in the Phoenix area know or can print the stls for this for a price? I have a M3D printer and it will take weeks to print all the pieces.

Download the parts, visit https://www.3dhubs.com/ and upload the stl files.
You'll find a selection of available hubs that can provide a printing service in your area, or posted from further away if necessary.

What program did you use to create the diagrams throughout the build guide?

Sketchup with a free rendering plugin

FYI to those using a 24v 15amp power supplies, after about 6 weeks of use an internal thermistor is likely to blow out from high heat. This is because the supplies are cheaply made and the thermistor is only rated for about 6amps assuming you will not be using all 15 amps regularly. Keep this in mind when making the decision to use a 24v heated bed.

FYI for anyone ordering hardware fasteners from Mr. Metric, use the code METRICWORLD now until July 31st for 20% off online order. I don't work for them but figured it would save some of you a little cash. I didn't personally try the code.

what is the squarebackground on ur bed do u have the file or where can u buy it ?

It is just printed on the heated bed circuit board by the manufacturer

Something I don't understand is that to find the D-Bot on thingiverse, if I search for "D-Bot" I never see the original D-Bot listing. I have to find it through my bookmarks, my liked items, or by parts listed as being remixes of parts for the D-Bot. Just seems weird.

That aside, I have a frame assembled, but I need to order some steppers, a build platform, and some stepper drivers.

Really excited to get the printer up and running! Thanks again for all the really awesome work you put into this design, Spauda!

I think thingiverse search is using the retro google logic where '-' means return only searches without the term after, so D-Bot actually returns everything for 'D' without the word 'bot' in it.

If you literally search for "d-bot" including the " " then it will be first.

What is the best way to extend the length of the heating element's blue braided wire on the E3D v6?

Solder some more wire on the end?

Thanks much appreciated advice.

So I'm currently building this and opted for the 24V power supply are there any things to consider when hooking up the electrical I'm using the electrical diagram that was provided for the build that uses a 12V power supply. I don't want to burn anything up I didn't take into account the fan I bought as its 12V and will smoke for sure. Not very good at electronics and am reaching out for advice and build tips?

You can power everything off of 24 volts directly if you use the correct components - heatbeds, hotends, fans, controllers, etc are all available in 24 volt versions.
I'm using a RADDS board (plugs into 32 bit Arduino Due) which has a MOSFET output that is rated for 15 amps at 24 volts. It can power a large 12" x 12" 360 watt heatbed directly. No SSR needed.
Stepper motors have much better performance on 24volts - especially with low inductance motors and suitable stepper drivers.

Use one of these https://www.amazon.com/Nextrox-Converter-Regulator-Step-Down/dp/B00BWKXTUU to power everything but the bed. Use the 24v supply to power the bed and the aforementioned converter. Bolt the converter to one of the aluminum rails for heat dissipation

How much plastic do you need for it?

At least one 1kg spool

Thank you

any idea to why when the Y axis goes home it triggers the endstop and doesn't want to stop ? :(

Before a print or when controlling it from a pc? What software are you using?

im just using pronterface to dial it in atm.... i have tried it in simplify3d ... same thing..... its acting as if there is no endstop at all.... all the other ones are fine

Click the endstop with your finger, make sure the light goes out. I'm not sure about pronterface but in rep host, you have to input bed shape and origin point so it know where it should be homing to.

yeah light goes out ok.... i have wired it using the 3 pins straight to the board rather than in your diagram... could it have something to do with that ?

Check your end stop placement on your board. You could have them connected to the wrong pins.

I don't understand what you mean

i have wired up the x and y axis end stops up with 3 wires in each to the board, you have the positive wires and neg wires from both switches joined to save wire routing...... mines just wired up a little bit differently

That shouldnt matter as long as you are still connected to the proper pins, it just saves a bit of wire.

If you have some time to spare, I don't think it would take too long to download repetier host and set it up like I have mine, that way we are comparing apples to apples and we can see if it is maybe a hardware problem or just a difference in pronterface. Instructions are in the build guide section 12

let me have a play about with it ..... i will swap it with another endstop just incase... then i will wire it same as your diagram.... just incase

i appreciate the offer and if i dont get it fixed i will take you up on your offer if thats ok ?

thanks :)

Rep host is a free program and making software changes is easier than swapping hardware or rewiring things. Just an idea.

I dont know that i did but its ok now ... i swapped the switches over and back again ...works a treat ! doing my first print as i speak !... need to calabrate my E3D Titan extruder but looks good ! will update my images when i get a sec :)

thanks again for all your help... and great printer dude !

i tried the M119 to see if it is triggering and it is as it should

Might you have had the end stop plugged into the wrong pins for 'min' or 'max' endstop?

no ... dont think so... i only changed over the switches and it worked fine .... as long as its working im happy :)

Does anybody know a method to disassemble the wheels once the bearings are in there? I want to change to metal shims but the bearings are impossible to budge.

where'd you get your metal shims?

I just inserted a screwdriver at an angle through one side so it rested against the inner race of the opposite side bearing and lightly tapped it out. It might depend on the exact tolerance of the bearings you have

This worked perfectly, thank you!

Use a vice to hold the OD of the wheel and an ~8mm lock neck socket and tap out the bearings.

This doesn't seem to work due to the inside rim running round the middle of the inside of the wheel between the bearings, but thanks for the suggestion.

Is there a Facebook group for this printer. I'd like to get together with some other UK builders to get a parts list together.

A FB group would be awesome, I have built one myself and also from the UK

Jul 5, 2016 - Modified Jul 5, 2016
PJ79_Alpha - in reply to MontagueFlange

Just a quick update for UK builders: Here's a cheap source for the square nuts.

See below

Cheers. Got a bit too excited there...

There's a facebook link somewhere on this page.
Here's a uk forum for D-bot building - https://forums.overclockers.co.uk/showthread.php?p=29723769

Jul 5, 2016 - Modified Jul 5, 2016
PJ79_Alpha - in reply to spauda01

Arrgh! You found us! :D
Wondered why there were plenty of guests viewing that section. Hope you don't find our scrabbling around too hilarious :)

There is also a Facebook group-: https://www.facebook.com/groups/1711323699127948

Montague, most of the parts are easy to find and we can help you out with all that no problem in the Overclockers thread. Only thing we're finding hard to get hold of over here are the correct square nuts.

I tried to register so I could say hello and offer help but registration criteria seem to be pretty strict. Feel free to message me here with any questions you have from across the pond.

I really do appreciate you taking the time to try joining to help us out. You'd be incredibly welcome there. Really.

What was the issue with registration?

Itried signing up and it kept me in limbo for a few days then I got an email saying -
'Unfortunately your registration at Overclockers UK Forums did not meet our membership requirements. Therefore your registration was deleted.'
Probably because I'm not a proper Brit.

We have members from all around the world, so I can't see that being an issue.
I'll get in touch with an admin and we'll what we can do to sort it out.

Does the D-bot's firmware use Marlin's bang-bang mode for bed heating?

So it just uses the default PID mode?

Yes there are more details in the build guide

A friend recommended this for me, and I was immediately hooked, and I want to do this build as a summer project :)
But...I want to ramp things up a bit, and expand this to a 50x50x60cm build area, for a special project I always wanted to do.
like a, first time a ...... is 3d printed :)

I am a Modelmaker so building is no problem for me, but the electronics side is a bit hazy for me, with the amount of options available.
And the first burning question is, do you think the electronics and stepper motors can handle such a frame ?
or can you suggest a upgrade that I can go for, I really also want to try a Volcano nozzle and print big fast, that's also why I think the electronics might not handle the faster load ?
I don't mind spending a little more on more sturdier electronics.

I already made the choice that the z-stage will have a slide rail on all 4 side pillars with the two lead screws in the middle on bot sides.
and change to a 24V setup for the amount of 2.85mm material I already have.

If you really want a build area that big you'll need increased rigidity. I've been working on a few mods to the original C-Bot that has been very effective for that: http://www.thingiverse.com/thing:1629139

If you already have the bottom 2020 extrusions it should be trivial to change the parameters for the bottom corners

SpiffBot CoreXY 3D Printer

Hey, I'm already watching your build :)
I haven't ordered any material yet, but I am confident that I can make the frame rigid enough, with your info and others :)
The enlarged Ultimaker I did, already had problems with vibrations, but the V-frames will solve a lot, and maybe adding sidewalls or crossbars will do the trick.
Also my z-bed will be supported in all 4 corners of the frame, this will also increase stability a lot :)

I will first print most if not all the parts, and slowly, after some running hours adapt any problem areas and maybe convert them to metal parts.

What I'm less confident about is getting the correct electronics together, and have it all work together :)

Try the Cbot link in the description, it has better parts for more support on bigger frames. I don't think bed sizes beyond 300x300 are a good idea.

Can you give a hint why the larger bed would be a bad idea :)
the length of the belts ? rigidity ?

Depends how much time you're prepared to wait for a print... If a week per print is okay, by all means go large.

I already have an enlarged Ultimaker with double height, and I already make prints that last up to 2-4 days,
so that is not an argument :)

The objects I want to print will be finished afterwards, and are models without much detail, more smooth surface shapes, so the bigger printser will be perfect for these, and adding a Volcano hotend will sped up things even more :)

uglybob - in reply to Xeno

The issue going large is more to do with the bed support on 2 leadscrews, the C-bot uses 3. Going bigger again would also raise its own issues.....

This is a big printer...
https://thegreatfredini.com/2015/05/02/the-maestro-of-3d-printer-building-jetguy/

So wish I had the skills to build one of these.

I thought the same thing... but ultimately, its not that hard. Only thing is getting the profiles cut but apart from that, its fairly easy. Take your time, find a local maker hangout and get help where needed.

The instructions are very good too and will help you a lot along he way.

Getting the metal cut would be the big problem. No where near me for any of that. We don't have maker hangouts over here :(

You don't have access to a neighbor's miter saw? With a decent blade it cuts through the aluminum extrusions like butter.

Nope. I live in flats in a tiny village in Wales. No shops or places to get this sort of stuff done.

Ooznest the V-slot supplier in the UK cut to length for you. That's what I did.

You can buy the v-slot and have it cut here: http://ooznest.co.uk/V-Slot/Linear-Rails

Nice thanks :)

I actually went to a shop fitter to get my extrusion cut.. cost me $20. They cut alu extrusions for display cases and the like.

Jul 2, 2016 - Modified Jul 2, 2016

I'm having weird issues with homing. The x and z axis works fine. For some reason when I home the y axis, it doesn't retract like the othet two. It just hits the endstop and stops. It's suppose to hit the endstop, retract a little and slowly home again. Tried changing the retract distance but no dice.

Upgraded Marlin to RC6. Moved the Y endstop to the front (I like having my home at 0,0,0).

I'm not sure which did it (or both), but everything appears working as intended.

I notice that when I move my Z up its nice and quiet. Moving the Z down however, creates a lot of squeezes and high pitches. Tried spraying it with teflon dry film lubricant. Kinda helped, but not really. Anyway use a different lube?

Mine does the same at high speeds but fine any other time. For me I think its more the tolerances and the leadscrew nut material. Mine was advertised as copper.. not sure if it is or brass like most.

Ya, its definitely not as "tight" as I would like it to be (as compared to my PTFE/delrin nut on my other printer). I was tempted to get the PTFE nut to see if it would help, but not at $12/each from China.

Yeah.. i did consider these as well...would be a nice setup though.

http://www.makerstore.com.au/product/8mm-acme-nut-block/

Got a pair of antibacklash nuts. Going to see if this helps.

Can you provide more details, or maybe a video?

The problem is homing with the y axis.

With both the X and Z, homing works fine. That is, it would first move towards and hits the endstop, retract back (5mm is default) then moves back to the endstop more slowly.

But for some reason, when the Y axis homes, it just moves towards the y endstop, triggers it, and stops. It doesn't do the second, finer homing like the other two axis. I have no idea why it does this. The endstop works fine, otherwise it would just keep moving if it didn't. I even swapped the endstop itself.

Something is just weird with firmware, or my RAMPS board is defective. I even changed the adv configs so the retract distance is larger (10mm). The other two axis again behaves appropriately, but the Y just triggers the endstop and stops.

I'm going to swap the RAMPS for my spare Rambo 1.3 and see if my board is defective.

I'm assuming you can drive the Y axis in both directions? ie: for some reason the motor only works in one direction, hence why it wont move back and re home? Throwing it out there.

All the axis have no problems moving in both directions.

Cool assumed you would have checked but had to ask :)

I moved up to RC6 of Marlin due to issues which resolved it all for me. Plus I could use E1 for the second Z stepper motor.

That's a good idea. I'll try that next.

I think RC6 added to have 2 z axis end stops.. one for each side so both motors can stay in sync. I havent done it myself but may in the future. I need to get my heat bed mount fixed so I can use the whole thing.

In figure 19 it looks like the Z stop is on the wrong side but it is correct in the pictures below it.

The picture is correct... might want to have a closer look. :)

Question on the ramps enclosure fan - in the BOM it looks like it is showing a 40mm fan, but the enclosure file you reference (http://www.thingiverse.com/thing:1352320) it is using a 60mm fan.

Obviously if we use that enclosure we'd need a 60mm, but is there another enclosure that we would use the 40mm fan in your BOM?

Ramps 1.4 Enclosure for Vslot

The 40mm fan in the bom is just for a generic fan for board cooling

Should I be concerned that the gantry is out of square with the frame? The frame is square, but when the left side of the gantry wheel plate is flush up against the left idler assembly, the right is off by about 1/2". I can drop that down to about 1/4" by pulling the frame out of square on the left side (The left side of the frame ends up at 14.125", where as the right is 14".)

Are your rails cut accurately? Did your printed parts come out clean? Loosen the bolts that hold the Hbar ends to the gantry rail and retighten evenly

My problem ended up being that my belts were too tight, and one was slightly tighter than the other causing it to pull the one side.

I am having this issue also but before belt tightening. I'll be disassembling the gantry tonight to get it square and post results.

I'm planning to do a larger build - 400x400 or 500x500 ... is there any reason I couldn't use the 76oz stepper motors in the BOM. Or should I get some 84oz motors.

If I get a different motor - do I need to configure them/tune them etc?

Printers with beds larger than 300x300 are very impractical, even with a volcano extruder large prints which take up most of the bed would take several days to print and if the power went out or you had a layer shift all that work would go to waste. If you printed small stuff you would be wasting huge amounts of power heating a giant bed you don't need. The larger and heavier the bed gets, the harder it is to keep it level and stable and with longer belts and a bigger XY gantry prints will have ringing artifacts. If you want to print giant objects just make them in pieces and assemble. Biggest size I would recommend anyone going on this style printer is 300x300x600 and that's only if you really know what you are doing and you build it well.

But back to you original question, I dont know.

Thank you for your experience and advice.

how many of those chain liks did u need ?

Is there any reason you have to use the ~1/4" spacers with the wheels? I'm currently on the Z axis, and I'm finding them difficult to thread onto the bolt. I can drill them out if needed, but I also noticed that once I adjust the wheels to be tight, they're no longer butted up against the spacers anyway.

That doesn't sound right. If you havent already, post your build by clicking 'I made one' and upload some pictures of the problem areas

I bought some aluminum spacers at the hardware store. I'll get photos up later this evening.

finally starting the build but am noticing the shims and spacers are pretty tight on the m5 screws, to the point where the spacers and wheels need to be threaded on. Should I open the diameter of the part and print again or is that ok?

I had to increase the ID by 0.4 mm and decrease the OD by 0.3 as well to have a better fit and better wheel roll. It also made installing the wheels less PITA.

Depends on the accuracy of your printer but I just drilled mine out to the right size.

Everything has fit perfectly and snug except for these... I could probably drill out the spacers but the shims would be really tough...

I used metal shims that come with the wheels. Was a kit of wheel, bearings, shims and locknut.

You are right, would be pita to drill those. If you want to reprint, scale in the x/y by say.. 5%? see how it goes.

i just used a hot solder to melt the excess plastic away instead of trying to drill or spending the time reprinting.

I have been trying to build a D-Bot and have been having issues with the v-wheels wheels binding and not rolling along the v-slot. In an attempt to isolate the issue I placed a wheel, spacers and nut on an m5 bolt and tightened it up. When attempting to rotate the wheel i noticed that even though the spacers were transferring the clamping force to only the inner race of the bearing the wheel was no longer smoothly turning. I ordered metal spacers to put between the bearings instead of the printed spacers but am out of ideas.

Is this a common hurdle that everyone had to overcome?

Yes it was definitely a pain in the ass to get all four wheels to make full contact and not have it bind. I think I'm still having some minor problems. Right now its good enough until I decide to take everything apart and redo it.

Jun 29, 2016 - Modified Jun 29, 2016
beepbeep - in reply to bzillins

As everybody sets the distance between bed and nozzle differently, some people squishing the first layer down, others having it virtually floating, there's little chance that the printed spacers are going to work for everybody. Best thing to do is print them, caliper them, adjust and reprint until you get the size exact.

I'm thinking of swapping to the metal ones too. Are these the ones? Just the regular mini v wheel shims? http://ooznest.co.uk/V-Slot/Shims-Spacers/Mini-V-Precision-Shim

Those are the ones I bought, I'll let you know how they worked Saturday

Did you try them?

I replaced mine too - they make a world of difference.

I did and they worked very well. I damaged a few bearings on removal so you may want to have a few spares around.

If your shims are slightly too thin, they will allow the bearings to bind up. I had good luck with printed shims but others prefer metal shims

I cleaned up the spacers and probably undersized them accidentally, that makes perfect sense.

Thanks for the quick reply!

My wheels had to have 2 shims in the middle, not 1. After digging around, the website i purchased them from mentioned it too. Always wondered why they gave an extra shim when I bought them :)

Is anyone else having problems with the STL files?
And are these the latest ones?
Thanks

Anyone out there using a chimera or dual extruder set up on their D-Bot? If so are you using dual bowden extruders?

Also if anyone has their D-Bot enclosed would love to see that!

Can I use E3D All-metal v6 HotEnd Full Kit 3.00mm Bowden (24v) with this? All my current filament is PLA 3.00 mm
Also what about Bondtech QR Universal Extruder - 3.00mm?

I suppose if you had a 24v power supply, you might need to modify the extruder bracket. I've never tried 3mm filament so I'm not sure what other changes you would need.

Confused about changing filament using this bowden system.

I'm used to the direct drive extruder and I heat up my nozzle, push a bit of filament and then pull back - which pulls everything out of the hotend, then load and push the new filament through the nozzle until I can see it coming out. Then purge the old by extruding new.

Do you pull out the ptfe tube at the hotend side when changing filament? - Or - how is the best method for changing filaments?

Heat up the hot end.
Manually retract the filament by using the feed knob or command via repetier host or other program to retract 1000mm, which should be more than plenty to get out all the way out.
Insert the new filament, manually feed it forward or command the extruder to feed via software depending how long your bowden tube is.
Keep feeding filament 10mm at a time until it flushes out the old color and the filament is coming out at the new color solidly.

Does anyone know where to source a flat aluminum plate for a 300x300mm bed? I've looked at 12x12+ aluminum cast plate (Mic-6) but it only comes in 1/4" at the thinnest, which is pretty heavy stuff.

Why not a thinner aluminum plate as a heat spreader with glass on top to keep it flat

I'm worried the glass will warp over time when big prints press it onto the aluminum plate.

That won't happen unless you get really crappy glass or you are heating it to like 500C or something crazy

Hanging around /r/3dprinting I've heard of some cases of the glass warping along with the aluminum bed in normal conditions.

This comment has been deleted.

I use a 3/8" thick MIC6 plate (for some reason it was cheaper than the 1/4" plate) and it heats up quickly and does a pretty good job. It probably doean't come thinner than 1/4" because they can't guarantee flatness below that

Jun 26, 2016 - Modified Jun 26, 2016
geoxile - in reply to spiffcow

Can 2 typical nema17 motors really support that weight? That must be over 6lb, and another 3+lb from the aluminum extrusions.

Yep. I even use bed correction instead of springs so its constantly moving. It works fine.

Are you still running 1/16 stepper drivers? If not, think 1/32 would make difference?

Created a Facebook group to discuss this excellent printer

https://www.facebook.com/groups/1711323699127948/

Facebook is okay for kids posting photos of cats... I think Google groups is more suited to grown up things.

Would you mind if I created a Facebook group for this excellent printer?

Can you send me the path for that group when you have it set up? Or post it here

Go ahead

cool...can I use your pics? I'm in the process of making mine still

sure, just give credit and link back to http://www.thingiverse.com/thing:1001065

D-Bot Core-XY 3D Printer
Jun 24, 2016 - Modified Jun 24, 2016

I'm having aweird issue with slicing, specifically, so far, on the right motor mount. It's creating some mid-air triangles like there's hidden geometry in the STL file. It's highlighted yellow as a bridge in this shot:
https://i.gyazo.com/e501de6097190af75222a0af220d973f.png

Any insight?

Jun 25, 2016 - Modified Jun 26, 2016
KDan - in reply to Kittera

Change layer height very slightly in Simplify 3D. For example, if you are printing a primary layer height of 0.2000mm, change it to 0.2001. That will fix the problem. This is a known bug in Simplify3D ver 3.0 that comes up occasionally. It may have been fixed in later versions.

However, some of the parts definitely have geometry problems. I'm attempting to edit the Right Rear idler and it is a mess. The Left Rear is OK. I'll be moving on to the motor mounts next. I'm working on modifying all the parts with extrusion channels to allow the use of hammer t-nuts without the risk of them bottoming out. I am really disliking the square head nuts. They bite into the extrusions and sometimes remain stuck when loosened. Makes it very difficult to make fine position adjustments.

Is this in Simplify3D?

I've just run the latest right motor mount through my copy of S3D (Version 3.1.0) without any issues. I used a 0.2mm layer height with 30% infill. If that helps.

Is there a wiring diagram and parts info for using a 120vac heated bed? Just not sure how to put that together.

If you are unsure, then don't do it, Stick with 12 or 24v systems. 120vac isnt something you want to play around with if you are unsure.

What he said

I get what you're both saying .. though I'd be unsure of doing any of this build without spauda01's excellent build guide.

so - if I stay away from the 120vac - what is the wiring diagram for using a 24v heat pad?

Jun 20, 2016 - Modified Jun 20, 2016
uglybob - in reply to goldentuna1200

Same as the build guide except with a DC-DC SSR and a 24V power supply, which is what I have done. And obviously the ground live etc will go to the 24v power supply and not to 120vac. Little common sense is required.

Is there a particular SSR that's recommended for a 12V 270W heater? I can't seem to find any DC-DC SSRs that would safely sustain 23A (I'm skeptical of these chinese ones on amazon and ebay).

I've heard these Fotek SSRs are junk and can be dangerous.

If you allow them to get too hot and overheat. You can get heatsinks and fans for them too.

At that current level, you might just go with a mechanical relay and control it in bang mode. Use thick enough wires and make sure all connections are strong, that's a lot of current. Maybe consider a 24v or 120vac bed

I am getting a 110VAC heater in, just some cheap silicone one from China, not sure about the quality. Besides the added danger of mains VAC the printer would need an extra big enclosure to fit my PSU (an ATX PSU) and also fit a second plug separately for the 110VAC heater. It would be a big thing to print before I can put the printer together. I guess if I can't find a SSR for this 12V I'm going to use the 110VAC heater. I don't think I could stand the clicking of a mechanical relay for hours on end.

So those relays are dangerous, but your chinese low quality mains heater is okay?

Sounds like you'll be burning the house down.

The 12V silicone heater beds all come from China too. And for the same power they use significantly higher current.

Im tossing up wether its worth going for a 300mm x 300mm heated bed of the 300mm x 200mm. Does anyone know if the dimensions listed in the build guide will allow for the larger bed to fit with ample space for the x carriage to move about?

I was also wondering if its worth printing in PETG over ABS or PLA, I noticed that allot of people in the comments section have used PETG on their build. Its just that I have some spare roles of ABS that I should probably use.

I've used ABS and printed on a Wanhao i3 which is supposedly incapable of it, so if you can print ABS then I would recommend doing so.

However, note the shrinkage of ABS will cause some parts to fit very tightly. I had to reprint all of the motor mounts scaled up by 2% in order that I could fit the motors without the mounts snapping or bowing... So scale up!

If you are capable of printing ABS with good quality then go for it, it's just easier for others to use PLA or PETG.
The frame sizing diagram leaves enough room for the nozzle to reach every corner of the bed and the alternate frame diagram is just 100mm deeper.

Jun 19, 2016 - Modified Jun 19, 2016
Calum736 - in reply to spauda01

Thank-you spauda01, I didn't even realize your awesome build guide had the dimensions for a 300mm bed. I have gone ahead and ordered all the extrusions I need. Can't wait to start building!

Hi, just wanted to say I'm doing some research for my own CoreXY design and this is incredibly well designed! Nicely thought out, nicely implemented, very clean and concise, so very well done! I'd use it myself except one or two things don't meet my criteria. Very impressed though :)

Just curious, what are the couple of things?

Sorry, that's what I'm adding in my design!

  1. Direct dual drive instead of Bowden, just personal preference.
  2. Experimenting with using belt-wire couplings to reduce stretch.
  3. Experimenting with a 25:1 gearbox to give 8 micron resolution without micro stepping (personal preference, micro stepping seems illogical to me)
  4. Using the 4 V-slot pillars as linear guides instead of adding rods. As there are 4 should give much better stability too.
  5. Guess this isn't really an upgrade but I'm adding my full graphic screen. Small things and all that rot.
  6. Unfortunately going to wire crossover due to symmetry and stability along XY carriage rails. Made this lovely little crossover system that uses two small canted bearings to pass the wires smoothly over each other. Also added in the tensioning mechanism to the back idlers. It's a shame, I really loved the dual line style.

I just finished printing the main frame parts. I'm heading back to my hometown tomorrow for a few weeks (away from printer :( ) but that's where I plan to set up my printer, so will see how it all goes.
Thoughts?
Also putting out a very brief video skimming on the topic tomorrow, can see it here: https://youtu.be/doZjsvfNmXA
Don't expect the link to activate till 11AM UST.

In the build guide it goes through the process of running PID autotune for the bed. I understand PID should not be used if you are driving the bed through a relay (as the relay really doesn't want to try and deal with PWM modulation).

Does anyone have thoughts on this?

You're thinking of a mechanical relay, not a solid state relay.

Ah cool thanks.

I did a diff between your Marlin zip and the same version directly from Marlin, 99% of the changes happened at configuration.h, is that correct?

Also, I see there is a new version of Marlin (1.1 RC6) that does include support for CoreXY, have you tried that one? Any improvements for us? :-)

Cheers!

Hi There,

I have been running on 1.1 RC6 for three weeks now and all seems to be working fine. I just compared the configuration.h and made changes and adjustments where needed. The only other change I made was in pins.h for the button direction on my LCD controller.

Only change I noticed was that the homing issue was resolved and I can home any axis while any of others are homed.

Anybody looked at the E3d heated bed and would you need a separate power source for it? I like the option to only heat zones based on the print seems much more efficient but not sure if the ramps can handle that sort of control.

I looked at it briefly before, I don't think it heats in sections it just uses traces of varying impedance to give a more even all over temp

What are your thoughts on this bed? http://www.ebay.com/itm/Improved-200x300mm-Dual-purpose-12V-or-24V-Heatbed-PCB-3D-Printing-reprap-USA/331881520007

I like it because it has zip tie strain relief built into the board.

Very true spauda01. The tracks are of differing size to allow a more even temperature even at the edge of the heated bed.

To quote e3D:

"We tested quite a few bed designs and types, but they all had the same critical problem: the temperature at the edges was significantly cooler than the measured temperature in the centre. This means that despite having your bed set and reading 110C to print ABS comfortably in the middle of the bed, the temperature towards the edges could be as low as 95C and this means parts printed at the full extents of the bed are going to suffer from warp and detaching from the bed.

Our solution was to provide more power at the outer regions of the bed in order to compensate for the lower temperatures being measured there. By using slight variations in the width of the PCB heater traces we are able to selectively provide more power to regions that would otherwise be running cooler. This results in a much more even temperature distribution over the surface of the bed."

oh i thought for some reason it was like the new gmax bed that heated in sections. But also seemed like a decent price if it is a quality part like most of E3s stuff is. I know they want an arm and a leg for the gmax bed.

I had been going to use the heated bed spcified in the BOM but I changed my mind when I heard about the e3D bed. The quality of the PCB heater is equal to or better than MIL spec PCBs, and I've worked with many of those.

so are you converting everything to 24v because that seems to be the biggest drawback to me. What if any are the ways around this. Can you isolate the bed. and still control it via the ramps. Seems way complicated....

No I'm not converting to 24V. I'm using a separate 24V PSU just for the bed. I'm using 12V for everything else including switching the SSR to control the 24V to the bed.

i don't see any amp ratings on the e3d bed. Does anyone know the specs

Filastruder tested it with the following result:

"Electrical data: 24v nominal (22.9v actual), tested at 10.01 amps at 25C (Fluke 179)."

Each of the Molex connector pins are rated at 5A and the bed uses four of them for the power connection.

Is the dc-dc relay in the BOM enough for this application you think. Looks like it is 40amp and up to 23v in and 60v out

Cool that works i already have a 15a power supply in the shop. Hope that will be enough.

Do yourself a favor and buy the SSR below instead of a cheap one. The cheap ones typically have an on resistance of 0.1 Ohms which doesn't seem like much but will rob 10% of your power input as heat. In a 24V 15A test I setup with one it was 79 to 80C at the huge heat sink. The one in the link has an on resistance of 0.006 Ohms and barely even gets warm at those current levels.

http://www.auberins.com/index.php?main_page=product_info&cPath=2_30&products_id=288

This may be a dumb question, but what units should we use with the stl files for the printed parts? It doesn't say anywhere in the build guide, and I tried mm, but it looks way too small.

Thanks, the parts I printed were just smaller than I expected. I really like your design, but I have one more question. Did you have an issues with the straightness tolerances of the vslot? Looking at the rails I received, they don't look very straight when I lay them on a straight surface.

I put them down on a wood table. Turned out the table was really warped, not the extrusion.

That's not good. Try other surfaces and complain if they don't look good

Dear designer thanks for share your design. Can I use rumba board to your design if its possible can you explain me how to configure codes? Thanks

Not the designer but have experience with Marlin.
If he's provided code, use it as it EXCEPT at the top of configuration.h where it says "define motherboard" replace the board he's using with the relevant name from the boards.h for the Rumba. Give that a whirl.
Basically all it needs is to know what connectors to send the signals to, so telling it what board you're using will let it do the rest. I hope this helps :)

hola, si quisiera poner una cama de 300 x 300 mm, que tengo que modificar?

Ver el final del documento Guía de creación de los cortes de carril que necesita para 300x300 .

What cable is acceptable to connect the heater cartridge to the RAMPS? The silicon wire that comes with the hotend isnt long enough to make it all the way.

Overkill?
http://www.jaycar.com.au/Wire%2C-Cable-%26-Accessories/Hookup-%26-Power-Cable/General-Purpose-Hookup/Red-15-Amp-DC-Power-Cable/p/WH3073

Jun 15, 2016 - Modified Jun 15, 2016
beepbeep - in reply to uglybob

I think hot end heaters are generally around 40W, so 40W / 12V = 3.33 Amps

I've used 18 gauge (only because I bought 200m a few years ago so still trying to use it up) though 20 would also be fine (and still suitably over-spec'd).

Handy table: http://www.powerstream.com/Wire_Size.htm

The link in the BOM for a few Hardware items are broken. Can anyone tell me if these alternatives will work?

M3 Socket Bolt, 20mm: http://www.mrmetric.com/M10842
M3 Socket Bolt, 25mm: http://www.mrmetric.com/M11563
M5 Socket Bolt, 40mm: http://www.mrmetric.com/M11220

The M5 is also very expensive, about 3x the cost in the BOM. Where can we get them cheaper?

just send them an email or call they will get you setup. the guys at mrmetric are very helpful

If you call them they can get the ones in the BOM.

Thanks! Some of the items they were getting in stock soon so he made a note in my order to send them out when they arrive.

How can I modify the firmware to not use endstops? thanks.

I remixed another spool holder to suit the D-bot here http://www.thingiverse.com/thing:1625705

Spool Holder for 20mm V-Slot/D-Bot/C-Bot - 30 x 100

Do you think the square nuts make any difference from the misumi T-nuts? I guess t-nuts are supposed to be a better fit for the slots of 2020 extrusions but does that matter?

Do you guys think something like this would work at all?
http://www.thingiverse.com/thing:1061769

M4 T Slot nut

I have tried the three (3) of them. The square-nuts from Mr. Metric are too small contact surface, as said before. The T drop-ins and the T Sliding nuts have an issue when connecting plastic parts that have the V-Slot elevated profile. Remember that both the nuts and plastic parts have elevated profiles to compensate the extrusion slot empty space. When both profiles are in touch there won't be enough movement to tight the plastic part, extrusion and nut ending with loose joints.

I ended sanding each T Sliding nuts to remove the elevated profile achieving a better surface contact. If I knew that before I would have bought something like this ones:

https://8020.net/shop/3206.html

Yeah i think I'm stuck sanding the nuts to... though wouldn't sanding the plastic be easier...

Have you tried putting the T-nuts in flipped? I guess the hammer nuts can't be helped.

The T-nuts (sliding or drop-in) are unable to be flipped upside-down like the square nuts do to their shape. The are made to have the best contact surface used as designed.

Jun 14, 2016 - Modified Jun 14, 2016
geoxile - in reply to rodelvalle

I see, so the printed parts designs have to be changed to get rid of the extrusion for the v-slots?

Are those really a dollar a piece?! Mr. Moneybags over here

Square nuts make a very secure frame, I'm not sure if T-nuts are worth the cost.

Having said that though, I'm doing a second build of the D-bot and have ordered these to try out (were recommended by someone in the comments here - much further down):

http://www.banggood.com/100pcs-M5-Hammer-Nut-Nickel-Plated-Carbon-Steel-Nut-Aluminum-Connector-T-Fastener-Sliding-Nut-p-1048442.html

My D-Bot is made using entirely those. They're great - and you can add / remove stuff after it's been built :)

I got these, apparently they need to be sanded down as where the eyelet is, it is extruded and bumps into the plastic on the printed parts made to fit the extrusions.

I wondered that from looking at the photo. The nuts I originally got (square nuts 10mm x 10mm x 3mm with no chamfer - totally flat) do a good job but they won't quite fit in as standard, I've been using a bench grinder to chamfer 2 of the lower edges then they fit quite snugly - flat against the extrusion when tightened and can't be popped in or out from the face of the extrusion.

I do about 50 nuts at a time at the grinder to break up the monotony of it... No big deal, but I would love to find something that is both low cost and 'just works'.

Yeah that was by me. I bought them after my concerns with the square nuts from Mr Metric.

I've got a mixture of t-nuts (http://www.makerstore.com.au/product/tee-nuts-25-pack/), square nuts and the drop ins from BG.

IMO: The T-nuts are the best if you can afford it, the drop-ins work better than the square nuts.

(Apologies for not giving you credit by name bob - laziness prevented me scrolling to find it :)

I also saw these on banggood... They look like they'll fit though I'm not 100% sure.

http://www.banggood.com/50pcs-M5-T-Sliding-Nut-Zin-Plated-Carbon-Steel-T-Sliding-Nut-for-2020-Aluminum-Profile-p-1048439.html

Jun 18, 2016 - Modified Jun 27, 2016
KDan - in reply to beepbeep

They will fit, but they will bottom out on the raised channels on the printed parts just like the hammer nuts. The ideal solution would seem (at first glance) to be to use pre-assembly t-nuts like the ones from openbuilds or like these -

http://www.aliexpress.com/item/Zinc-Plated-Tee-nuts-for-building-machine-M5-bore-50pcs-per-bag-Free-Shipping/32345778338.html?s

Unfortunately, those have the threads recessed a bit and M5x10 screws can barely reach the threads when a washer is installed. (I have some and tried) M5x12 screws might work great thou if the screw doesn't bottom out in the channel. (UPDATE: It does...)

Ultimately, all of the parts with the raised channels could to be remodeled to allow a hammer T-nuts (or the ones you mentioned) to be used. The raised channel serves a purpose, so it should not be entirely removed - just in the area near the bolt holes. I've modified a few of the original C-Bot files myself, but I haven't seen any easily editable files (such as STEP files) for the D-Bot files anywhere.

UPDATE: I decided to tackle this. I've modified all of the parts that have raised extrusion channels. Hammer T-nuts can now be used without risk of them bottoming out on the raised portion of the printed parts. Modifying STL files was tedious. STP files would have been much easier...
I am planning multiple builds of a modified C-Bot/D-Bot type machine .The Hammer T-nuts are much more versatile, will cut assembly time and aren't that much more expensive than the square nuts (6.5 cents each vs. 4 cents each).

Jun 28, 2016 - Modified Jun 29, 2016
PJ79_Alpha - in reply to KDan

Hi KDan, is there chance that you could upload those modified files if possible?

Edit: Sorry, just noticed you only updated yesterday. No rush :)

When I get back from vacation later this week, I'll post the revised parts. There are quite a few :-)
I also have a lot of totally new parts, which in sum probably constitutes a remix of the machine. The machine isn't printing yet - that's probably at least two to three weeks away. The last component - which I just ordered - is an endless GT2 belt of a specific length.
I don't want to publish any of those parts until the machine is up and running and I can fully document everything.

Totally understandable.
Nice work and good luck with the build :)

Those look a lot better than the first BG link. I too want to know if these will work with the build. I'd be willing to try them out.

I ordered 1 pack to try them out so I can let you know once they arrive.

I didn't order the square nuts yet and just decided to order these instead. Square nuts would be $8 with probably some shipping and tax on top, 4x 50 packs came out to just under $20 with free 6-9 day shipping and no tax. Hope they work!

Square nuts are cheaper and capable of doing the job. t-nuts are better, more surface area on the extrusion, less chance to damage the profile.

Another question. Would there be any upgrades to add dual extrusion?

Look in the remixes

spauda01 - one more HUGE THANKS! for such a fantastic job of putting this together and such an outstanding BOM and Guide. Man - this is great!

LIke most - I'm looking to push this to a larer size - and have used the calculator, etc to figure what I needed.

Couple of questions though:
1 - on the calculator it refers to the Z-Platform: Gantry, and the CoreXY: Gantry, I wasn't sure - but it looks like those corespond to R & Q respectfully on your frame reference diagram. Could you confirm if that is correct?

2 - It seems that most printers out there stay in a similar 'smaller' size. Is that because of the limited size of heat beds or limits on stability and accuracy of going larger?
I guess the question really is ... is there a point where this design won't handle the stabily/speed/accuracy for a given size. e.g. 500x500 bed and 500 lead screw. - what would be largest size (within reason) that this design might handle?

I don't need a heated bed - as I've been using a Lexan (polycarbonate) build plate and don't need heat/hairspray/glue) - so I'm really not limited on what size bed I could make. (link to my build plate thread ref: http://goo.gl/A22fP1)

I'd like to hear the answer to this too

In the BOM it says that the printer has trouble maintaining 100c for ABS. I would like to have the option to print ABS in the future. Are there any alternative heat pads that someone could recommend?

well, for ABS you will likely need an enclosure to begin with. as for the bed, you can go 24V!

Yeah I was planning to build an enclosure once it's running. Have tons of spare acrylic! So just grab a 24V bed heater? I don't know a huge amount about the electronics side of things yet. I DID buy the 12v PSU listed on the BOM already. I'm guessing it won't be able to send the full 24V to the heat pad in this case? If so, I'm wondering what components need to be upgraded to make it work great with ABS?

Running the bed at 24v seems to be outside your skills. Just look at the printer that this page is remixed from, the Cbot. He used a different 8x12 bed and he prints abs

Jun 10, 2016 - Modified Jun 10, 2016
Marksman79 - in reply to spauda01

Thanks for the reply! I did look at the c bot, and noticed that he uses the same 12v power supply that this build uses. A different, more expensive bed but one that can handle 24v just like the one in the D bot. And the wiring diagram is also the same. So what are the changes I would need to make in order to use the D bot bed at 24v? Is it just getting a 24v PSU and soldering the wires to the 24v points on the bed? It seems that the relay is good up to 32v.

And how much of an issue is the heated bed running at 12v as far as ABS printing goes?

There are plenty of beds out there that can reach 100C with 12v, the bed pcb I am using just happens to have a slightly higher resistance than others so it doesn't consume as much power and doesnt get as hot. Running your bed at 24v is more advanced than you think and it involves more than just getting a different power supply and connecting it.

Get a 24V silicone heater mat (Aliexpress has loads, many of which can be made to your specification) and a 24V power supply. You can step down from your 24V power supply to run your electronics at 12V if you don't want two separate power supplies.

I bought my bed from avanti circuits, they have an ebay store and sell a 12x12 heated bed for $48 free shipping, and it can draw up to 20A if I remember correctly, so should heat up quite fast. I plan to mod a 600W PC PSU to supply enough energy to this.

are these the folks you are talking about. http://www.ebay.com/itm/12-X-12-Heatbed-Kit-w-Relay-Prewire-and-Thermistor-for-3D-Printing-/262314890386?hash=item3d132f9492:g:kWgAAOSwDuJW1dWd

They recommend an extra powersupply that seems a little overkill if you are not running it at 24v. In the middle of my build but looking at his and the makerfarm 12x12 bed.

That's the one I got, but I bought the relay separately (the one from the BOM), so instead of $69 paid $48. I will just use a 600W PC PSU, and should have plenty of power for this without needing a separate PSU.

I'm considering trying to minimise the Z-axis motor "drift". Would it be worth me taking my 5 steppers and in some way testing them out to try and find 2 which are very closely matched to use for the Z-motors?

Quick question..... how did you bond your cork sheet to the underside of your heated bed ?

Jbweld epoxy

thanks mate :)

Another question. Would there be any benefit in the following modification:

1 - Cut an extra Q piece, and add it to the other side of O and P.
2 - Add extra 8 wheels to that side, plus the printed parts
3 - Move K very close to the center of H and J

Would this add more stability (as now the bed is supported from the 4 corners), or unnecessary bulk? By my calculations, I will have some leftover extrusion, so could potentially use it for this...

Comments are appreciated :-)

Unnecessary

Can these V-slot extrusions be replaced by something else? Like normal extrusion or something?
I can't find these where I live and it would cost 96$ to ship if I were to buy them from OpenBuilds, that's too much for shipping!

What country are you in?

The problem is the wheels... V-slot has the profile to mate with the wheels, other standard extrusions do not.

You may have a vendor in your country selling V-slot (we do in the UK), so it's not limited to buying from openbuilds.

Theres a remix that replaces most of the rails with standard Tslot extrusions but some rails would still have to be Vslot, thats just how it is designed.

I bought 1000 square M5 nuts and they don't fit the V-slot. The link from the BOM is dead. Does anyone know the dimensions that the nuts have to fall within to fit?

link in the spreadsheet works fine for me.

Jun 8, 2016 - Modified Jun 8, 2016
beepbeep - in reply to beepbeep

My nuts are 10mm square x 3mm thick. I presume the ones from Mr Metric were 8mm square. If I chamfer two of the edges I can get them to fit... Got a lot of time at the bench grinder coming up :)

Jun 6, 2016 - Modified Jun 7, 2016

Hello, I'm planning to build this dbot. I want to calculate extrusion lengths for 400*400mm bed and planning on using a 500mm lead screw to gain as much z height possible. Will it be okay to use the cbot rework calculator from original cbot page? With offset lead screw option and adding 30mm to the bed width as the calculator suggests? Any suggestions would be really appreciated. Thank You

Hello! What LED controller did you use?

There's a link in the "additional comments" column of the "12v 5050 LED Strip" row. The controller case is easy to pop open to extract the board, and it slides right in to the optional ramps 1.4 enclosure listed under Thing Details.

I wondered this too and couldn't find it in the BOM. I think any cheapo (chinese variety) LED controller works, but I really didn't want any colour changing effects or remote control so just bought white LEDs (not RGB... this isn't a christmas tree) and will wire to 12v.

Everything is in the bill of materials

Jun 4, 2016 - Modified Jun 4, 2016

I am running into another issue.
Once I got everything up and running and calibrated, I started my first print. The first 3 or 4 layers went on fine and then the nozzle stopped heating and I got a cold extrusion prevented error followed by a heating error.
Now the strange thing is that this only happens during a print. I can manually extrude a whole spool with no temp drop-off so i know it is not a hardware issue. I even swapped out to a different E3D (Genuine) that I had on my other printer and same results.
I am not very savvy programmer, could this be a firmware issue or a setting I am missing?
Seems to me like once it drops from 205C on the first layer to 200C on the next that it doesn't stop on the way down?
UPDATE: It happens when the part fan turns on, so when the infill layers start. It just starts dropping and never stops.

Make sure your part fan nozzle isnt unintentionally blowing on the heatblock and cooling it down

I disabled my cooling and its looking great now (at least for a 1st print).
It drags on the bed if its pointing any further down. I can always re-design a new shroud that is less intrusive to my setup. I print mostly PLA anyways so cooling is not as critical for me.

Post some pictures to your Dbot make page of the nozzle and fan duct, if you followed what i did it shouldnt be that different, mine works pretty well and doesnt blow too much on the hot end and it still has clearance from the work

Done.
I have to remake the part anyway in PETG. Its PLA and melted a bit for being so close to the block.
The only thing I can see different from yours is the positioning of my heater block wires. Can't see that really being an issue for cooling conduction.

You have the long end of your heatblock pointed at the duct, look again how my hot end looks

The end of the fan duct had slightly melted because it was PLA. I re-printed in PETG and now it is working fine with cooling fan enabled. The melted end of the duct allowed for increased air volume to be blown onto the heater block, causing the block to reduce in temperature.
Lesson to all: Fan duct in ABS or PETG for optimal results.

You still need to look at how your heatblock is oriented. I've been using a PLA fan duct for months just fine. The fan duct was designed with the assumption that the long end of the heat block would either face sideways or towards the front.

Alright I will try it out. Always up for experimenting.

Jun 4, 2016 - Modified Jun 4, 2016

Is there enough clearance in the Y axis to rework the print carriage to put a laser module or second extruder with the 300mm wide bed?

Also on the Z access, since I haven't built this yet I am not sure how much play there is on the bed, but would it make sense to extend the shaft column up to fit a spring and a nut to ensure there is always pressure down don the primary lead screw nut to avoid any movement in the z axis? I'm sure the steppers could handle the extra friction from the second nut given the gravity assist pulling the bed downward.

Was there any particular reason you chose the stacked belt layout for corexy? Does it give any problems on the carriage because the belts are on different levels?

The moment (torque) forces from the 20mm offset are small and easily handled by the mini wheels of the XY carriage. The belts are offset in this design to allow the belts to run parallel and not need to cross in the back like other coreXY designs. At the time of the original Cbot design this was novel, now lots of design CoreXY designs use this approach.
A distance of 20mm was chosen so that the belts could run through portions of the extrusion to provide a cleaner and simpler design. You could reduce this to the belt width plus a clearance (say 6mm +2mm), if you redesigned and didn't want to run the belts through the extrusion.

About the corexy design, do you know what would happen if x and y axis motion systems had different resistance? Like if I used two different types of linear guides for the axes.

Each belt will have a component of X and Y so I think it will be fine. The belts should still be tensioned similarly though and both guides should have a relatively low resistance to travel as that is desirable for any linear guide. You should take a look at the differences between an H bot versus a CoreXY setup.

Jun 3, 2016 - Modified Jun 3, 2016
geoxile - in reply to cfeniak

That's very helpful, thanks. I've been looking into adapting the D-bot design to use smooth rods or linear guides. Do you think the torque from the 20mm can be handled by a pair of x-axis smooth rods arranged next to each other (as opposed to on top of each other)? I assume linear guides can.

~16 inches is quite a long span for smooth rods, thats one of the advantages of the vslot is that it doesnt sag over spans

Wouldn't a pair of 10mm rods be fine? It'll only be supporting a carriage for a bowden hotend and the x-axis will lose a bit of span if I were to use smooth rods.

Jun 3, 2016 - Modified Jun 3, 2016
spauda01 - in reply to geoxile

Ultimately you're talking to the wrong crowd :-p, I adopted the Cbot design specifically because I don't like smooth rods. I think that was cfeniak's thinking too.

Check out the fusebox for a smoothrod based corexy.

I actually did consider the fusebox but I didn't like the frame. I've seen the spinoffs with 20x20 extrusions but in general the one leadscrew approach and the offset base (the feet) look strange to me.

You're free to remix this design however you want, It's totally open source

Thanks senpai.

You could, but why would you want to? Do you mean just for the XY bar so that you can use a specific type of extruder carriage? That would makes sense as there are carriages made to specifically fit that arrangement. Not a great design though for spanning distances, vertically spaced is better IMO.
There are lots of CoreXY designs out there that use smooth rods already so it would makes sense to design off of those as the integration of V-slot as the linear motion guide and frame is one of the design highlights of this printer (or fatal flaw if you don't like the concept).

On the rods I've talked to some other people designing printers who claimed that wheels had some play that good smooth rods didn't. But ideally I'd like to use linear guides over either. And D-bot (and C-bot) seems to have good documentation and an active community, and the design is good. It just needs a few changes to fit a different motion system, at the expense of some lose of volume.

KDan - in reply to geoxile

I have used Delta printers with both MGN-12H linear rail, and Delrin rollers riding on aluminum extrusion. In my experience the rollers running on extrusion as just as rigid as the linear rail bolted to an extrusion. If someone claims that they have play or slop in their roller wheel setup, then they don't have them properly pre-loaded. On a Delta printer, I prefer the the linear rail because they are maintenance free. That is what my Kossel has.
On this CoreXY machine, the V-slot wheel setup has much lower moving mass. The linear rails are HEAVY. You don't want to be throwing the weight of the linear rail around if you are after high speeds and high accelerations.
Smooth rod is a double looser... they are not rigid enough across large spans, and it you use larger diameter rods to try to compensate, you really have a boat anchor on your hands.
The only drawback to the Delrin wheels that I've seen it that they, and the extrusions - need to be kept very clean in order to run super smoothly.
For what I believe the design objectives of this machine are, I don't see it benefiting from smooth rods or linear guides. It would only make it less rigid and/or more sluggish. As a Delta printer fan, I'm actually interested in making this machine even lighter on its feet, not heavier and slower.

Jun 6, 2016 - Modified Jun 6, 2016
geoxile - in reply to KDan

The plan for this printer is to print <10mm parts as accurately as possible and also mount a dual extruder with direct drives (Flexion dual extruder for mk 10). I have a hard time believing that the V-slots an rollers could be as well fitted as linear guides. As for rigidity, the Y-axis 9mm or 12mm guides will be mounted on the top of aluminum extrusions while the X-axis will be a 12mm or 15mm guide mounted at each end to the Y-axis guide blocks. I don't think the Y-axis will have any trouble since it's fully supported by the extrusion it's mounted on, and Misumi's aluminum extrusions show that the 20x40mm extrusions have greater mass/m than the Hiwin MGN12 guide (rail + block). I could even mount a MGN12 guide rail onto a 1515 extrusion and it'd only be 12.5% more massive per meter than a 2040 extrusion. Adding wheels might make things more even.

KDan - in reply to geoxile

2040 extrusion is overkill, that's why I redesigned with 2020 (Half the weight). Printer is not operational yet, but with the rollers properly preloaded, it is very rigid. A Kossel I've used which has the rollers instead of the MGN12's that my Kossel has feels just as rigid. I wouldn't have believed it at first either. But seeing is believing. The V-slot, V-wheel setup is very good.

I have to agree with spauda01 - you'd be much better off with a much smaller machine.
As far as SLA machines go, you can build a LIttleRP for much less than the price of this printer (not counting the DLP projector of course). No one printer can do it all. Personally, I still prefer my Kossel for small medium sized FDM prints. You do have to spend a little more time getting on intimate terms with the beast however.

geoxile - in reply to KDan

I'm a little skeptical but I might try V-slots on a different project. For now I almost have the design for linear guides nearly done, though it'll have to wait a few days while I'm away.

I still need a FDM printer for those larger utility objects, but I'll consider the littleRP for a future project. According to the creator there's a LittleRP2 coming up and it'll be the same price as the current littleRP, so it's probably worth waiting a while for that. I'm mostly concerned that the print volume might be so small that I'll rarely use it, in which case just ordering prints from 3Dhubs or shapeways might be more economical. But we'll see.

Why are you going to use such a huge printer to make tiny objects? Look into a Form2 or something SLA based

I want it to be scalable of course. That's just an example of what I want to achieve in terms of accuracy and precision. And a Form 2 would be 3.5x the cost, which just isn't in the budget.

It was part of the Cbot design. It works fine, the print carriage only moves in x and y, its not able to twist at all

This is pretty simple, but putting the M3 nuts in their pockets in the rear idler assembly and getting then to line up with the idler bearing screws can be a PITA, The pockets for the nuts are MUCH deeper than they need to be and the nut will fall far below the proper position to line up with the screw.

Take your calipers, set for 8.5mm, insert the M3 nut in the pocket and then insert the back end of your calipers in the pocket. Turn the part so the nut falls and sits on the end of the depth measurement bar on your calipers. The 25mm long M3 screw for the idler bearings should line up with the nut and the screw will go right in.

You really don't even need that nut, the bolt threads into plenty of plastic. It's just a leftover from the old design

I printed the parts on my Delta printer which print holes very close to their specified dimension. Correct me if I'm wrong, but I think they are 3mm holes. I found that I could turn the 25mm M3 screws into the holes almost by hand. If I tried to tighten them with a hex key wrench, they slipped with very little force. That was the only reason I put the nut in.
They might have stayed in place without the nut, but in my case I felt better putting them in.
For someone whose printed parts had slightly undersized holes, I believe you are correct, they nuts would be totally unnecessary.

Is the M3x10 for the extruder tensioner flange a mistake? The picture shows the tensioner is counter sunk, which would work, but the stl file isn't. Did you mod the part or the length of the bolt?

Fixed

Thanks!

I guess everyone just uses a longer screw with some washers.. I have to reprint my extruder anyway, as I had the parts printed on 3dhubs and the hub decided that 30% was more than enough infill (I am new to this, so didn't know until it was too late). I hope the parts last long enough to print new ones. I have an ABS glue made up and am fixing splits and cracks as they appear as best I can. I have a roll of PETG waiting for my SSR to arrive.

Also, as a general note for others, I tried the white PU GT2 belts, and they are not suitable, they are too stiff and don't take the corners without rubbing on the parts. Stick with the black ones.

Well that's weird. I've never noticed that before and I'm not sure what happened to the file. It's supposed to be an M3x10 countersunk as shown in the photos. I'll fix it tonight and reupload. I'm surprised nobody noticed and I'm not sure how people have been working around it

Finally up and running!!...sorta
I have uploaded all the firmware and only the extruder motor is able to turn.
All motors make a noise when I try to manually move them in Repetier, but they only move the axis maybe 1mm.
Is this an issue with the stepper drivers? The steppers should be plenty strong to work in this application.
I have them adjusted to 0.5v, could this be the issue?
Just wondering if any of you out there are running into similar problems.

Did you put jumpers under each driver board

This was the solution. I had totally forgotten to put them in during my initial setup.
I found this out late last night.
At least it was something so simple!

Unless you bought the same stepper motors and are using the same drivers as the creator, you will need to calculate the Vref for your particular components and set accordingly.

What drivers / motors have you got?

I've got everything printed (in ABS) but just can't get a perfect print of the H-bar ends, they always seem to develop a split at the very top of the flat base just before it meets all the ribbing. I guess there are some weird forces going on here - the split doesn't develop until the part is cooling after printing.

I've even tried rafts, and though I did get a good print I couldn't get the rafts off cleanly enough that I'd be happy using the part.

I was wondering if I should reduce the number of shells and use a 50% infill or something for these parts - appreciate we're after strong, solid parts here, but I've gone through half a reel just on these 2 parts and somewhat lost where to go from here.

ABS is often a problem with larger parts with sharp corners. Sometimes printing hotter to get better layer bonding helps. ABS has its place, but some of the parts in the D-Bot are just not ABS friendly. I only use ABS in parts where pliability or heat resistance might be an issue. I would not discount PLA. I've had good success when using PLA on other printers I've built. Not all PLA's are created equal. Some are more brittle than others. Printing temperatures can have a significant effect on the strength of PLA parts also.
I'd agree that PETG is probably better. It has better layer bonding than ABS and has greater tensile strength. It is also less brittle than PLA. However, for really large parts, I've had warpage problems with PET and found PLA was the only type filament that would get the job done.

I'm all printed now... I don't use PLA at all so am using what I've got. I consider PLA fine for those printing out toys (99% of domestic 3d printing it seems) but hopeless for structural parts due to the insane level of brittleness - tightening down a screw into a PLA part goes through me!

I purchased my first spool of PETG to print the parts for the D-Bot to avoid the shrinkage problems presented by ABS. Printing a couple of smaller parts first allowed me to tune the printer settings for the PETG and got quality prints quickly. Had no problems with shrinkage and got good bed adhesion with glue stick on glass. All structural parts were printed at 100% infill none required rafts, although I did use a brim on several of the smaller parts. I printed all parts on a well used and modified DaVinci 1.0.

Don't give up - I found the D-Bot build to but a great project and I couldn't be happier with its performance.

I hadn't considered PETG on my Wanhao i3 - I thought I was pretty much restricted to ABS or PLA, though I print with ABS mainly flawlessly so I think I might give PETG a try soon.

I've managed to print one of the H-bar ends successfully now (inspired by uglybob's comments below I made a flimsy shroud for the whole printer out of thin art-card which seemed to keep the heat a bit more uniform - and being there to take the part off the bed shortly after printing instead of it finishing in the middle of the night helped avoid splitting on cooling I think), so I should be okay.

Now to order the remainder of the parts and get busy.

The splitting can be from too much infill (~>80/90%), bad layer adhesion, or uneven cooling of the part.

I dont use ABS because of these "quirks" but keeping the whole printer and the part in warmed chamber while its printing and letting the whole lot cool evenly when its done helps reduce those stress splits. Splits from part of the print cooling and shrinking quicker than the rest. Some people even just put a cardboard box over the whole thing.. not sure this works for you and YMMV.

Thanks Bob. The printer (only a Wanhao i3) doesn't have a cover, but it is in a pretty-well sealed room where there are some computers rendering so the ambient temps are around 30 degrees celcius at all times with no draughts.

I'll try completely covering it with a box though... Will try anything.

Thanks again.

I print almost exclusively in abs. Layer adhesion can be a problem at low temperatures. I usually print at 255-260.

I've been printing at 250 with good results generally, just had problems on the H-bar ends and the rear idler parts with them coming apart on cooling, but might try going higher in future. It seems to help to get the parts off the bed as quickly as possible - the bed retains heat and keeps the bottom warm while the upper parts are cooling/shrinking, and it's this I believe that caused the parts to develop splits.

With the relay, does the bed heat up faster? How long usually takes to go to 60-70C?

The relay is only dependent on what heat bed you use. If its rating or supply(AC/DC) is more than what your controller can supply, then you will need the relay(DC/AC,DC/DC).

Awesome job on this project, the build document is so well done a complete novice should be able to follow it. I've started printing out parts for my own build. Looks like it would scale well... any thoughts on whether or not it would scale to 24x12x12 or larger? The extruder carriage would be heavier, and the heated table would be heavier, so would the motors be able to handle the extra weight without stalling?

Do you mean 12x12x24 (LxWxH)? This guy did something similar http://www.akeric.com/blog/?page_id=3063

No, I'm thinking larger X-Y axis. I have a Solidoodle 4 and the least accurate axis seems to be the Z... I've never printed anything with more than 4 or 5 inch height, but I need more X and Y. Right now I have to print some things in pieces and sand them to fit and glue together, so I'd like to be able to make some larger items. I was looking at heated build plates and saw one that was 500x500mm for $180, and thought that might be a good size. I imagine it would be easy enough to adapt your build to accommodate this plate, but wonder if the added weight might cause stalling on the Z axis, or even the extruder carriage because the V-channel is longer/heavier.
I'll probably start off building a 12x12x12 with your build docs, and if everything goes well (meaning I don't screw it up royally) would like to try something bigger. Your design would be very easy to modify for a bigger X and Y, but I think the Z might need 4 lead screws, powered by 2 motors and all connected with a belt

Expanding up is easy, expanding X and Y seems like a huge pain and probably not worth it. Look at the link I posted to see what kind of quality he gets on the 24inch tall build

Jun 1, 2016 - Modified Jun 1, 2016

Ok, assuming I go for a 300x300 bed, and also want to go for a 500mm leadscrew instead of 400mm, would these cuts make sense for the 20x40 extrusions?

1.5m: 620 488
1.5m: 620 413 448
1.5m: 620 433 433
1.5m: 620 413 463

Any other things I should take into consideration (besides the also longer GT2 belts)? Will 100mm extra on the Z mess things up?

Cheers!

Jun 1, 2016 - Modified Jun 1, 2016
Carrot_or_Stick - in reply to Piglet

Hey Piglet,

Thanks for replying to my comment below. Good catch on making 4 x 1.5M lengths work! Didn't catch that the first time through. From what i can tell the extra 100mm is the only change that we would need to make for the 500mm lead screws for the frame. The belts we need are 2 x 2.2M (from another reply in these comments). Worst case scenario is that the design wouldn't work with the taller frame but at that point we could just cut off the extra length from the rails and rods we have and go with the original design.

The only calculations I've done are for the original build and the 300x300 version. Any further modifications are up to each builder to decide

Mr Metric doesn't carry M3X25mm socket bolts? Is there an alternative?

I would contact mrmetric i sent them the list of bolts i needed and they had everything but one and suggested an alternative to what i needed. Even loaded it in my cart for me.

They also might just be out at this time. You could try reaching out to them (I heard they are helpful) to find out when they will be restocked.

bolt depot maybe

yup, thanks! Excited to build this bot.

You happen to have a link to the bolts you found as a replacement on bold depot? Their site is not very user friendly.

Are there any considerations for the Z-axis bed when building a 300x300mm version? I'm worried about tipping of the bed on the far end without any support.

You need to move the lead screws forward and find the center of mass of the new larger bed so the bed is lifted from the center

Also noted to find the center of mass, take the whole bed assembly off and balance it on a piece of dowel or a sharpish edge so you can find the balance point from the front and back.

Hope that marks sense......

same as trying to balance a pencil horizontally across a finger?

How precise is the fit of the wheels on the aluminum extrusions? Is it comparable to linear bearings on good smooth rods?

Hello is there a reason you Chose PLA or can i just use ABS?

Its just what I had, if you can print ABS that would give more durable parts

It's a beautiful thing. Thanks for the detailed build guide - I hope to make this.

I am currently printing parts out for this build because I absolutely love how clean and organized you've made it.
Do you happen to know where i could find a setup to make it direct drive? I cross messaged over on The Director's Triple C/C-Bot page as well hoping he would be able to point me in the right direction. I still plan on using the E3D v6, but can't quite tell if that's the same hotend he's using.

Thanks!

Look at the printer this one is remixed from, he has a direct drive option

Will that extruder module work with the D Bot?

Congrats on your printer, looks really nice.

I got a question. Went thru the build instructions and i didn't see how you are adjusting the wheels fit the extrusions.Openbuilds does it using eccentric spacers but i don't see them during assembly. Wondering if you don't tight that way, how much play you get between wheel and extrusion.

Thanks

The D-bot has oblong holes for the X/Y axes to allow for you to adjust the wheels, and the holes are actually slanted to tighten the wheels against the frame as they're tightened. I'm finishing my build up this weekend, and it's pretty easy to adjust those.

Thanks. That sounds great. One more question on the parts. Do you happen to know what infill and layer height is recommended to print? Thinking 70% @ 0.2mm w/ 0.4mm nozzle. Maybe will go with 0.6 nozzle but 70% @ 0.3mm. Thinking PETG. Any advise and tips are welcome

Definitely no less than 70%, higher if you can. PETG or ABS would be more durable than PLA

I went 90% PETG.... absolutely awesome stuff.. no cracks, no stress marks.. works really well and strong.

first person to print something 12"x8" contact me... Not sure where i will be buried yet...

Cmon, this printer is awesome.. but the build volume is ludicrous....

Yeah it needs to be a bit bigger for sure.

You can make the 300x300 version. This printer will actually be a big upgrade in size for me as I am building the 300x300 version. I currently only have a 200x200x110 printer and it hurts me to turn down orders that I can't fit on my bed...

May 26, 2016 - Modified May 26, 2016

I have a set of 500mm lead screws (accidentally said threaded rod) that I plan to use in a future build along with a 12"x12" heated bed. Theoretically I should only need to use the cut guide in the appendix and add 100mm to the lengths of rails A, B, C, and D to use them right? I would probably need an extra rail to accomplish this and re-order some of the cuts.

Love the work you have put into this and all the help you continue to give folks building your bot. Presentation is spot-on too!

Jun 1, 2016 - Modified Jun 1, 2016
Piglet - in reply to Carrot_or_Stick

I don't think you need an extra rail, just a bigger one, see my comment above (waiting for OP's reply), theoretically you can accomplish a 300x300 bed + 500mm leadscrew with the following 20x40 extrusion cuts:

1.5m: 620 488
1.5m: 620 413 448
1.5m: 620 433 433
1.5m: 620 413 463

Still waiting for further replies before I take the plunge! :)

I wouldnt recommend using threaded rod, lead screws only

May 27, 2016 - Modified May 27, 2016
Carrot_or_Stick - in reply to spauda01

Bump (see edited comment above)

Sorry i meant lead screws. I have 2 500mm lead screws with the same specs in your design

Awesome build! I greatly appreciate all of the work spauda01 put into everything. I was wondering what the effects would be if I used these

(http://www.amazon.com/Nema17-Stepper-Motor-4-lead-Connector/dp/B00QEXSCE8/ref=sr_1_1?ie=UTF8&qid=1464273319&sr=8-1&keywords=nema+17)

steppers instead of the ones listed in the BOM. I already have them so I could save $50 if they'll work. I am not super savvy when it comes to the electrical side of things so I don't know if I would fry anything if I plugged these in without changing any settings.

Those are functionally identical to the ones listed in the BOM, however you get 80% of the rated torque. What this means is you will not be able to run the printer at extremely high accelerations without losing steps, and the extruder will be less powerful.

I prefer to use a geared stepper anyway, and for normal print accelerations (for detail), they should still be fine. The high torque is just to have more headroom and more flexibility when trying to take the printer to its limits.

May 30, 2016 - Modified May 30, 2016
KDan - in reply to Masterjuggler

Actually, those motors are quite superior to the ones called out in the BOM. I would say almost ideal. The only thing I would personally prefer is even less rotor inertia on the X-Y motors.

Holding torque is irrelevant - you don't print standing still. Torque at high stepping rates is what matters if you want to achieve high speeds and high accelerations. Those motors have an inductance of 2.6mH, the ones in the BOM are almost double at 4.8mH.

Lower inductance means those motors will have a much flatter torque curve. The ones in the BOM will start off with slightly more torque at 0 RPM, but once the motor starts to spin, the torque will start dropping much faster than the 2.6mH motors from Amazon. You can also buy those motors direct from omc-stepperonline for $9.16 qty 5. There will be shipping charges however, so you'll have to compare final prices. Either way, they will ship from China.

For maximum performance at high speeds, I wouldn't use anything less than a 24v power supply. The rule of thumb is up to 20x to 25x the rated voltage of the motor. Voltage ratings are mostly irrelevant anyway - current limits are what matter, The voltage applied to the motor varies enormously as motor speed - and reactance - changes. The goal is to achieve constant current. That is a primary purpose of the stepper drive.

KDan - in reply to Piglet

Not enough information on either one of those motors. No inductance values are given. The first one is described as 12v - that is often an indication that it is a higher inductance motor. I would not consider either one of those.

For low inertia motors to drive the X-Y axes, I'm using 17HD34008-22B motors. For the extruder and the Z-axis (single motor) I'm using heavier 17HD48002H-22B motors. Both are low inductance versions with values around 3mH. All will be run on external 24 volt stepper drive modules.

Jun 7, 2016 - Modified Jun 7, 2016
Piglet - in reply to KDan

Here is the info on each motor from the datasheets. If you can tell which one works better for extruder and x/y and z axis, that would be appreciated! :-)

http://www.aliexpress.com/item/Free-shipping-any-Country-4-lead-Nema17-Stepper-Motor-42-motor-NEMA-17-motor-42BYGH-1/32673417497.html

Series Model 17HS4401
Rated Current(A) 1.7
Phase Resistance(Ω) 1.5
Phase Inductance(mH) 2.8
Holding Torque(N.cm) 40
Motor Length(mm) 40
Step Angle(。) 1.8

http://www.aliexpress.com/item/NEMA17-Stepper-Motor-34mm-12V-1-5A-0-4N-m-for-3D-Printer-Free-Shipping/32666641594.html

Series Model 17HS8401
Step Angle : 1.8 °
Motor Length : 48 mm
Rated Current : 1.8 A
Phase Resistance : 1.8O hm
Phase Inductance : 3.2 mH
Holding Torque : 52 N.cm
Detent Torque : 2.6 N.cm
Rotor Inertia : 68 g.cm2
Lead Wire(No) : 4
Motor Weight(g) : 400g

http://www.aliexpress.com/item/NEMA17-Stepper-Motor-40mm-Long-1-2A-Free-Shipping/32341280650.html

Series Model sl42sth48-1504a
Step Angle : 1.8 °
Motor Length : 48 mm
Rated Current : 1.5 A
Phase Resistance : 1.6 ohm
Phase Inductance : 2.8 mH
Holding Torque : 5.5 kg.cm
Rotor Inertia : 68 g.cm2
Lead Wire(No) : 4
Motor Weight(g) : 360g

Cheers!

I'm leaning towards 2 x sl42sth48-1504a for the Z, and 3 x 17HS4401 for x y and extruder.

KDan - in reply to Piglet

First consideration - Low inductance
Second consideration - low rotor inertia
Third consideration - higher holding torque

I would prioritize your selection in that order.

Your selections look good to me!

Remember that a 24 volt power supply will give far better performance.
Also, DRV8825's don't work well with low inductance motors on higher voltage. They don't have enough dynamic range on the PWM output. If you want to use an inexpensive driver module, A4988's will work better in this situation even though they have lower current rating and coarser microstep options.

May 23, 2016 - Modified May 23, 2016

Spauda01, thanks so much for all your work on this! I've got mine built - I'm having trouble with a heavy 300x300 bed(lulzbot aluminum plate, heatbed, and borosilicate glass) and bed movemen/vibration while printing, so I'm going to try mounting the lead screws front and back and seeing if that helps. I've also printed out the rework c-bot STL's for the z slide backet that extend farther on the rail. If this doesn't work, I'll try and kludge together the triple c-bot from what I've got so far.

I'm looking to switch over to the e3d titan carriage that ElmoC designed - http://www.thingiverse.com/thing:1535933. The endstop mount is not included and I'm trying to figure out how to use with the carriage back. I tried in sketchup to modify the d-bot carriage back, but all I managed to do was mangle the model. :) Is anyone willing to take a stab at adding the endstop mount to ElmoC's design?

Edit - I messaged ElmoC and it sounds like he is going to try and edit/create a backplate.

C-Bot E3D Titan Extruder Carriage
by ElmoC
May 24, 2016 - Modified May 25, 2016
Chairman_Miow - in reply to nickmig

Hey, I did this recently. I'm at work right now but ill post some files later (I'm not sure about copyright issues with the files I modified). I added holes for the endstop and its protrusions and modified the parts to work with the diicooler ( https://www.thingiverse.com/thing:1025471 ) Finally I added the cable routing point at the top.

I cant guarantee that I have it perfect yet as its still the first iteration of my modifications and im still setting my printer up but so far it looks good

edit - hmmm according to the copyright on the Diicooler I cant share the modified fan shroud file. I can share the modified backplate and frontplate and it should be no trouble to add whatever fan adapter you like to it

DiiiCooler for Wanhao Duplicator i3

I WANT THIS PRINTER !!! THANKS FOR SO MUCH EFFORT TO MAKE IT AN EASY BUILD....ANYONE CONSIDERING A 1000MM LEAD SCREW FOR INCREASED BUILD H ??? OR WHAT WOULD ANYONE CALCULATE THE MAXIMUM BUILD H WITH THE CURRENT EXTRUSIONS??? THINKING OF USING 2040 FOR THE BOTTOM AS WELL TO CREATE ROOM FOR A BOTTOM PLATE AND SOME REMOVABLE DOWN WEIGHT??

Hello, first of all I am grateful for sharing. I have a question.
What are the dimensions of the sigma profide?
I must have missed it.
x, y, z sigma profile What measures?
thanks for the answer.

Hi bud,

I've sorted out the heatbed, it was a combination of the wire from the 5a to the 11a and the heatbed wires in D8 not being fixed properly (doh).

Is it possible that you could tell me the implications of using a psu rated at 12v, 12.5a, 150W. Will it work with this set up? (I.e did you fit a psu that is over spec? Or is the psu you have used what I actually need?)

Cheers

That power supply is too small and it will probably break. I only recommend using the parts in the bill of materials

Hi, how did you route the front stepper motor wires. I have OCD and hate wires :)

drilled holes in the extrusion and feed the wires down the middle. requires some pre-planning or lots of assembly/dismantling/assembly to marked it out and drill, feed cables and put it together etc.

Thanks. I though so much.

If you do that file down the holes so they are very smooth and put a couple layers of heatshrink around the wires where they pass through the hole in the metal. You don't want any shorted wires and with lots of vibrations extra care is needed

Thanks for the advice. I`ll use rubber grommets.

Having an issue with my heat bed.
The heatbed is wired up as per reprap and yourself suggests, however I get no output on the heatbed.
Any ideas?
(Also the D-Bot is amazing, thank you for designing this!)

Does the relay light up? Did you put a jumper wire between the two positive power inputs on the ramps board

Jumper is now on, ramps board lights up but still no output from bed

Does the relay light up

No, there's no light on the relay

I think that may be the issue, I assumed that was just a power input for the led controller

Does Z stay in sync? I like everything about the design, but thinking about a bigger build area (300x300, and maybe taller), and also using a belt and only one Z stepper. That would save cost of one stepper and ensure Z never goes out of sync. Thoughts?

KDan - in reply to Piglet

I don't particularly like the two motor setup either. I've started modeling parts for a single motor system to drive the dual lead-screws. Something like this - only with a much shorter and less unwieldy belt run.

http://www.openbuilds.com/threads/c-bot.726/page-87#post-35616

In my design, there are two idlers built from the same flange bearings used elsewhere in the design. The idlers and motor are both mounted on the same central extrusion. It is arranged in a "T" configuration to maintain a 180 deg belt loop on all driving and driven pulleys. The center portion of the "T" is very short. This gives the shortest possible belt length requirement.

I've thought about doing that too.
The two Z stepper things is just a classic reprap setup. It stays pretty well synced but after several prints and moving up and down long distances a few missed steps can add up.

Ok, looks like I found a solution for this without the need to redesign anything. If you are using ramps with a single hotend, you can simply separate the z motors in individual drivers, and let them sync individually with separate endstops, that solves the problem as each time you home, you get z to sync. I could not find the feature on your existing posted firmware, but it is available on RC6, it's called Z_DUAL_ENDSTOPS under configurationadv.h.

I will test it out once I get everything assembled.

May 20, 2016 - Modified May 20, 2016
infmz - in reply to spauda01

Is it possible to plug another stepstick in extruder 2, and mirror controlling signal from Z axis stepper in marlin software? I think that would partially fix that problem.

There would still be slight differences in wiring and components etc. the only way to have them perfectly synced is mechanically connected

Yeah, I have an i3 and after 5 or so large prints I have to realign because of missed steps.

I saw another design that uses 3 lead screws and a belt on the bottom, but looks overly complicated, so I think I will stick with your design!

May 20, 2016 - Modified May 20, 2016
Masterjuggler - in reply to Piglet

I was actually thinking about trying out 90 degree gearboxes with linear rod, with each box mounted right where the two steppers are currently. I feel this would be easier than belts due to no need for a tension system.

I'm about 30 prints in on this printer and I am definitely noticing misalignment.. I've got my two z steppers wired in series.

https://www.thingiverse.com/thing:372530

Nema 17 right angle gearbox with spiral bevel gears
by dasaki

As a suggestion.....If you want to go down the mechanical path than use the setup from the triple C bot. Its what im going to do if the dual motor setup doesnt work out for my 300x300.

http://www.openbuilds.com/threads/triple-c-bot.1255/

The biggest issue with the triple C bot design here is the requirement for super expensive lead screws with the ends turned down. 60 bucks each is a little bit too much for that...

If there was a cheaper, belt-driven, single stepper design it would be perfect.

I'd design it myself but I dont have any ideas for how the lead screws can be held in place at the bottom without the expensive lead screws

Where are you paying $60 each for leadscrews? Ballscrews maybe, but not leadscrews. They are about $10-$12 each.

I've used these for an adjustable Z-bed in a laser cutter I designed and they work quite well. What I did in the laser cutter build was to turn them down to 5mm with a lathe on one end. I machined a small step on the end in order to incorporate a thrust bearing to properly handle the vertical loads. A conventional 5mm ID ball bearing was then fitted along with a conventional GT2 drive pulley.

I plan to replicate this general approach with my CoreXY build. I'm in the process of modelling new printed parts to accomplish this and I'm also waiting for some of the other mechanical parts. When tested and complete, I will publish it.

I decided to go the route suggested by uglybob, thanks for that. As for the 60 dollar turned leadscrews from the triple C bot BOM here: http://zentoolworks.com/product_info.php?cPath=16_15&products_id=125
Sorry they're $46.00 not $60.00, I must have been mistaken. I couldn't find turned down lead screws anywhere else.

If you don't have a lathe, then yes - it can get expensive to have someone turn them down for you.
I don't think I'd put an 8mm ID pulley on an 8mm leadscrew. Not precise enough. Also, it's just not the right way to do it... :-)

Get an 8mm ID pulley (or drill out a 5mm one) for one side and an 8mm lock collar for the top. There are cheaper options, not all ways have to be done the same to get the same result. :)

i.e.:
http://openbuildspartstore.com/lock-collar/
http://openbuildspartstore.com/gt3-timing-pulley-40-tooth-high-torque-series/

You would need to add a few cm of rail to the sides or lose some z travel. Unless you either have the electronics mounted over the belts or mount the belt system over the electronics (both reducing z travel), you would need to mount the electronics on the back or side, out of the way. Of course, I'll need to do some rearranging if I go with the gearboxes, but I'd still be able to have everything bottom mounted and nice.

My 14 year old son & I have been looking for a good DIY 3d printer to build (we've discovered the limitations of our cheap delta printer) and this one looks like a great project to embark on.
I've managed to locate local suppliers for almost all parts in the BOM (I live in Australia) but I'm struggling to find the specified stepper motors (KL17H248-15-4A, 76 oz-in).
I'm just wondering if there are any Aussie builders out there that know of any local sources for these motors? Alternatively, are there other motors that I could use (such as these)?
http://www.ebay.com.au/itm/5PCS-59Ncm-Nema-17-Stepper-Motor-2A-4-wire-1m-Cable-for-DIY-3D-Printer-CNC-Robot/171828613083?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3Dd76c8e9c714d41e08a995c687d2bede1%26pid%3D100338%26rk%3D19%26rkt%3D28%26sd%3D171993372625

Thanks in advance
Matt

Hey mtodman, i made a d bot in melbourne and I used those exact motors (from austeppers.online) in my build! so far theyre working well (build pictures still incoming)

Hey Chairman_Miow, what drivers are you using with those steppers? How hot do they get?

May 19, 2016 - Modified May 19, 2016
Chairman_Miow - in reply to Helix70

I'm using chinese knockoff drv8825 's I bought 5 from here:

(http://www.ebay.com.au/itm/351478190866?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

They get pretty warm when I print but dont burn my fingers, I adjusted the vref to 0.55v (from memory - could be wrong)

Oh, so you are limiting the current to 1.1A?

May 18, 2016 - Modified May 18, 2016
spauda01 - in reply to mtodman

That link looks good, any stepper which is nema17, 1.8degree, and at least 76oz-in should work.

May 17, 2016 - Modified May 17, 2016

Thanks for the outstanding build, guide, and comment support. I'm running into a bit of a problem and could use some insight:

When adjusting the H-bar ends, the wheels are very sensitive to the tight bolts. This isn't too much of an issue for the top rollers, but it does come into play on the bottom ones. If I tighten the lower bolts enough to remove all vertical play, the spacers bind up the wheels and prevent them from rolling freely. If I loosen to the point where the wheels roll freely, they aren't held against the rail snugly. Any pointers on this?

I'm to the point where I'm ready to break out the Dremel and grind down some of the spacers so that they don't touch the outer bearing race.

The spacers shouldnt touch the bearing outer race, are you using the spacers from the parts page?

Well, I figured it out. I ordered spacers and shims from OpenBuils, since I didn't feel like fussing with so many small parts on my current printer, and I think the C-Bot BOM used them instead of printed ones. Turns out those spacers require a shim between the spacer and bearing.

Lesson learned: If you're going to be lazy, do your research first.

Thanks for the quick reply!

Yep, I noticed so many people having that problem on Cbot builds with their stupid spacers and shims so I said screw it I'll just design and print shims the right size.

What lead screw would you recommend since the one in the BOM has been ended by the seller?

Hi, is there any reason I can't use 60mm steppers? I can't tell if the Z axis has the room or not.

I'm planning to go the other direction - especially for the X-Y motors. If you are after higher printing speed, you don't need holding torque, you need a motor with low inductance and low rotor inertia. A 34mm motor with an inductance value of around 2.5 mH would be able to run at high speeds and have the torque needed to do rapid acceleration/deceleration without skipping steps. Big motors may have large holding torque, but they are not agile. They also tend to have stronger resonances and more vibration in general.

Interesting. Thanks KDan, I did not know that. So would you still go for torque for the extruder?

To a certain extent, yes. But a fair amount of speed is needed with Bowden extruders also. This because of the large retract distances. You want to be able to retract and re-engage the filament as quickly as possible. Large retractions incur delays that can become very significant if your extruder cannot move rapidly. On parts that require a lot of retractions, the delays can really add up.

The idea of simply selecting larger steppers in order to gain torque at operational speeds is often wrong. Here is an article that explains some of the reasons. It's targeted at Delta printer builders, but the same principles apply to all 3D printers.
http://reprap.org/wiki/Choosing_stepper_for_a_delta

I've been through all of this with a Kossel I built. I initially used sub-optimal motors in the build. Upon identifying the proper motors and installing them, I was able to turn up the step rates MUCH higher with no skipping or missing steps.

I don't know, try it on the sketchup model

May 16, 2016 - Modified May 16, 2016

Great job on refining the C-Bot! The build guide is fantastic and will likely make this project more attractive to a lot of people.
Build in progress. Modifying the HBar ends and carriage to use a single 20mm V-slot extrusion instead of 20x40mm to reduce moving mass.

balu - in reply to KDan

By HBar you mean the X axis? The 20x40 is used for the belt run. That's more an aesthetic reason, but to me a free hanging belt doesn't look clean.

Also doesn't the higher profile give you more stability against the rotation of the carriage as a result of the belt pulling at two different points? Besides sag issues, but those can probably be ignored at these lengths.

KDan - in reply to balu

Not quite sure what you mean - the belt is free hanging regardless of which extrusion width is used. With the 20x40 you have a wider extrusion behind it, but with the 20x20 the belt still runs very close to the extrusion and isn't what I'd consider to be hanging out in the open.

As far as stability of the X-axis carriage is concerned, I think it's pretty much a non-issue on 3D printers where there are virtually no loads... Except on the Z-axis carriages, where I am absolutely retaining the 20x40 extrusions. (But, by placing the lead-screws centrally under the build platform, those Z-axis loads have been dramatically reduced)

If you want a specific example of an CoreXY printer that uses a single 20mm extrusion for the X-axis H-Bar, look at the Fusion3 printers.

I think sometimes we fail to keep in mind the whole motivation for adopting the CoreXY kinematics. The goal is to be able to print faster by being able to use higher accelerations. You have to reduce moving mass to accomplish that. What is the point in eliminating moving motor mass and then replacing it with a heavier than necessary moving structural mass?

All of the parts for the new H-Bar ends and Carriage have been modeled and test printed. I'm now just waiting on hardware to start putting it all together. I'm working on optimizing several other aspects of the machine to reduce mass and inertia as well. I want this machine to have the agility of my Delta printer, but without the calibration hassles.

Are you revising the belt position to be centered WRT the carriage to eliminate twisting?

Also, I'm interested in what you're planning.. I'm working on a similar effort, though my goals so far have focused on increased rigidity rather than reduced movement mass.

May 24, 2016 - Modified May 24, 2016
KDan - in reply to spiffcow

spiffcow - I'm not currently looking at revising the belt position. That would entail remodeling many of the C-bot/D-bot parts to keep the belts in the same parallel planes, and I'm more interested in getting the printer up and running first. I don't expect the current amount of belt offset to be a problem, but I could be wrong. That's why we have to test out new ideas, right?
I feel that the stiffness of the carriage could be increased if necessary with alternate materials and/or mechanical reinforcement.

I think the twist might be more noticable with a 2020 extrusion, but I'd love to hear how it goes!

I'm planning on keeping the 2040 and the same positioning, but using a tight tolerance low friction slider instead of v-wheels to prevent unwanted movement.

There is no twisting or unwanted movement in the print carriage on the Vrails

spauda01, How can you have no twisting force if the belts aren't in the same plane? Or are you saying it's accounted for in the design?

I can't speak to your carriage specifically.. My build is a C-Bot with a direct drive carriage and an uncommonly heavy motor, and I can see a very small bit of twist when changing directions at high speeds. Perhaps it's just due to the lack of precision in the belt tension (they feel the same.. but I don't have anything to actually measure the tension with). Maybe my v-wheels are too loose -- I haven't been able to completely remove play on the carriage without locking up the wheels.

I'm not trying to negatively criticize the design. It's the best printer I've owned by far. I'm not doing this because I'm dissatisfied with the design, I'm just using it as a learning experience.

May 24, 2016 - Modified May 24, 2016
KDan - in reply to spiffcow

I think your variation of the design could possibly be why you are seeing the slight twist. You say you are using an uncommonly heavy direct drive extruder motor - but the original design calls for a Bodwen with almost no mass on the carriage.
The main idea of CoreXY is to reduce moving mass, but it will inherently have very long belts with "unique" belt routing requirements. It really wasn't intended for heavy loads - it was designed for speed. I do believe that Carl's original idea of using wedges on the carriage plates to tension the carriage wheels is not as good as using eccentric bolts. I may actually go with eccentric bolts on mine.

Anyway, since you want to throw around heavy masses, why not go with a more conventional X-Y Cartesian design?

Also, if you are seeing twist with your loads, that means a part is flexing. It almost certainly has to be the carriage. A more rigid material or a beefed up mechanical design could fix the problem.

I've imagined the possibility of a direct drive extruder on a machine like this too. But I think I'd explore a lightweight pancake motor extruder design in an attempt to keep the mass down as much as possible..

The point for me is more about the challenge than about the end result. The sliding carriage met with mixed results and I decided to shelve the project for now. I redesigned many of the brackets and the results are pretty good so far: https://youtu.be/RUivslqPWQ0

Now my problem is that the steppers are slipping.. Not sure yet if the X/Y steppers are too weak for my setup or if there's something else.. But the stability of the frame is no longer the limiting factor.

Steppers are losing steps?
What is the inductance of the steppers? What size are they (length)? And what power supply voltage are you running?
If you want high accelerations without skipped steps, you need:
1) Low inductance motors
2) High Power supply voltage
3) Lowest rotor inertia possible (shortest possible motors that will have sufficient torque).
4) A stepper driver that can properly handle #1 and #2.

Don't get fixated on holding torque. The torque curve is far more important.
Lower rotor inertia allows a motor to accelerate/decelerate faster with less current.

Looks like you are only using a single central leadscrew the whole way to the back, Hmmm.

Here are the steppers I'm using:http://www.automationtechnologiesinc.com/products-page/3d-printer/nema17-stepper-motor-kl17h247-150-4a-for-3d-printer

I'm running them at 12V 1A instead of 1.5 to reduce heat. I have never heard to get short motors for that reason.. Would it be better to switch to NEMA23 for that purpose?

Also, there is a corresponding lead screw in the front.. I'm planning to put a second set of rollers on the front too, but haven't gotten around to it

The carriage can only move left and right, if the carriage is twisting then the wheels are too loose

balu - in reply to KDan

You are right, my comment with the "free hanging belt" was more of an aesthetic reason than anything else (besides not being sure if it'd compromise stability).

Does anyone know the weight difference between a V-Slot / wheels carriage and one with rods / linear bearings just for the X axis?

For rectangular builds I always wondered why people not use the shorter axis for the moving one to reduce weight.

Instead of just building my own, I keep thinking about changes and what difference they'd make... :-s

KDan - in reply to balu

I don't know about differences in weights between V-slot/wheels and smooth rods/bearings, but I can tell you the difference between using a 20x40 X-axis extrusion and a 20x20. I just weighed mine. The 20x20 is 222 grams - which is almost a half pound, That means the 20x40 should weight almost a full pound. I believe that a half pound reduction in moving mass is quite significant - especially when trying to achieve high accelerations.

Can you post your revised gantry parts as a remix? I've been wanting to use a smaller rail for the gantry and in the future reduce the wasted volume on the sides of the bed to make the gantry shorter

I don't like to release anything publicly until tested. I don't have a functioning machine yet. I'll send you a PM about this.
I had to make the carriage slightly wider in order to avoid interference between the belt clamp and the carriage roller bolts. This may reduce X axis travel very slightly (or maybe not).

Good idea, that was one of my plans for a dbot 2.0

I am also interested in these mass reducing mods! I think I will just continue the regular build for now though so I can understand the original concept.

Did you use V-slot profile. But I can't buy V-slot. then, Can I use T-slot (Basic) profile??

You have to use Vslot for the rails which have wheels moving back and forth on. Look at this build which uses Vslot and Tslot to possibly save money - http://www.thingiverse.com/make:203841

D-Bot Core-XY 3D Printer

Hey spauda01. I congratulated you for completing the Build Guide on OpenBuilds earlier. I had sent a message here a while back but seems like it didn't get posted.

Anyway, I was asking how much further would the Z Axis motors need to be if I were using a 300mm x 300mm (with mounting holes on 320mm x 320mm square) bed?

Also, I printed a few carriages and was trying them out, could you tell me exactly how tight should the wheels be? Like should the carriage move if I were to hold the extrusion vertically, given that the carriage is only the printed parts and wheels with no other weight attached to it?

Based on a quick center of mass calculation, 95 mm instead of 69mm should do it. Exactly balanced would be around 75 + 20 or so for wheel resistance and printed load. You can try this on your own by picking a reference point (back of the back aluminum rear beam for me and working out the sums of the mass of a group x distance to the reference in the y direction all divided by the summed mass. You can group items together and measure the distance from the center of the group. For instance, the four plastic pieces that hold the wheels and its' hardware was 269.52 grams. It is centered on the beam, giving a distance to the back edge of 10mm. Formula would look like ((m1d1)+(m2d2)+(m3d3)......)/(m1+m2+m3...)

That's some good mathing. The experimental approach also works well: assemble the Zplatform/bed and balance it like a seesaw on some thin ledge and move it back and forth until you find the sweet spot

The wheels should all be evenly tight, they should be tight against the rails but not so tight that they resist movement when the belts pull on the carriage.

I don't know where the motors need to be moved to for a 300x300 build, I've never tried it. That will have to be figured out for new builds

This comment has been deleted.
May 13, 2016 - Modified May 13, 2016

Did you use the M5 square nuts in the V-slot on a 45 degree angle or straight?

Thanks for updating the build document too!

They go in straight and they tilt a little bit when tightened

Do you mean it grips on one side of the V-slot, but the bolt forces it not to angle out of the slot?

I'm not sure what you mean. I should of said rotate, not tilt.

May 13, 2016 - Modified May 13, 2016
Helix70 - in reply to spauda01

Right, so the two opposite corners of the square grip the V-slot?

Thanks for that. I really appreciate you answering my questions.

I think my DIN562 nuts are at the lower end of the spec, most are about 7.8mm, and the slot is 6.25mm wide, so not much overlap. Yours look a little bigger, more like the 8mm. With a bolt inserted, i can almost get the nut out of the slot, if that makes sense.

I'm not a huge fan of the square nuts from mrmetric either, the corners that grip are only small and tend to squash the alu if done up tightly. I found these and they seem to work well, cheap and free shipping.

http://www.banggood.com/100pcs-M5-Hammer-Nut-Nickel-Plated-Carbon-Steel-Nut-Aluminum-Connector-T-Fastener-Sliding-Nut-p-1048442.html

You might be onto something there. Have you tried them yet?

I didnt replace any of the square nuts but for a drop in and as a square nut replacement, they work very well. I'll be using them to mount the electrics(ramps and SSR).

Thanks, I did order some, so I will have options. It is a frustrating wait now for all the parts to arrive! Got my E3D V6, V slot, nuts and bolts, steppers and electronics. Next week I get the printed parts. Waiting on the mini V-wheels, heat bed, bearings, extruder gear, belt, pulleys, glass, LEDs, power supply and now some T Nuts. I can cut my V Slot when I find a friend with a drop saw.

Can't wait to start building, this is the project I have been waiting for.

They are certainly not as tight as Tnuts would be but the good thing about the smaller dimensions is that they can usually be inserted into the side of the rail for adding components after the frame is already built which is helpful.

I can imagine, but with your fantastic build guide, probably not necessary! :)

Hi Spauda, I really like the build plan. I will be building one soon(with 300x300mm Print Area). The one thing I would like to suggest for the builders is try using Aluminium Corner Brackets as they reinforce the structure better and also withstand to vibration for a longer life and steady print.

http://autosystem.en.ecplaza.net/9.jpg

I just want to say, thank you for putting in the time and effort to complete and put this printer on Thingiverse! I will definently be building this in the near future.

What's the point of the SSR, to keep a minimum load on the RAMPS board for the heated bed?

The bed draws too much current for the ramps board to handle safely

May 12, 2016 - Modified May 12, 2016
dgcaste - in reply to spauda01

Ok. I noticed you have your 12V hooked up to both 12 and 24V pads on the heated bed. Is this more effective than just hooking up to 12V?

Edit: oh shoot, I'm re-reading the table and for 12V both are required to be hooked up to -.

Thats just how the bed is configured, check out the vendor page for the bed via the bill of materials

I noticed that in your build guide you include the glass bed with PCB heater assembly. You have said to either buy glass with notched corners or glass that fits inside of the PCB bed screws. What size is your glass plate then and/or why did you then use the binder clips? Thanks.

The glass is 12 3/8" x 8 7/16", the binder clips are required to hold the glass on the pcb

Thanks. I noticed in your pictures that the edges are rather curved? Can you explain how you did that?

Which edges?

The edges of your glass plate. They're curved to allow room for the screws?

I cut the glass corners with a tile cutting dremel. If you buy glass from a hardware store or glass store they might be able to notch the corners when they cut the class.

Nearly done building, I'll post a Make once I have it looking a bit better. So far, I have everything mounted and all axes have been tested and move as they should.

Is it at all possible to make an mk7 version of your extruder?

I see cfeniak has one, but it's mount doesn't play well with the D-Bot design.

It was not meant for the C-Bot (or D-Bot), but it's predecessor. To use a MK7 in a direct drive setup versus a geared setup you would need a huge nema 17 stepper as it has reduced mechanical advantage due to the diameter differences you mention. To use the MK7 with a standard sized stepper look for a greg's wade type extruder remix that can take a 5mm bolt instead of the old school 8mm setup.

May 12, 2016 - Modified May 12, 2016
Masterjuggler - in reply to cfeniak

I actually made a planetary gear box with a 3.8:1 ratio that mounts directly onto the stepper with a 5mm output. works pretty well. I know the mk8 is the "upgrade" to the mk7 due to the reduced diameter, but with the proper amount of torque, the smaller diameter is detrimental due to the reduced surface area contacting the filament, and makes filament grinding likely.

I could just modify someone else's extruder with the mounting holes for the tube holder, but I am not proficient enough with cad software yet to make the e3d bowden extras mounting hole.

yep, absolutely

Is it possible for someone to make an mk7 version of this extruder than can be mounted on the side of the extruded, and still accept the bowden extras that came with the V6?

Here are the original files (I thought this was linked as a remix here but it isn't). There is a 123D file there that you can modify the design to meet your needs. What you need to do is shift the motor alignment to the side the distance of the mk7/8 differential. Leave the filament guide pieces where they are. This one doesn't have the bowden mount sized, but is left to be drtilled out. I would measure the bowden extras and size it appropriately before printing. Give it a try and if you still need help let me know.
http://www.thingiverse.com/thing:456788/#files

Direct Drive Bowden Extruder; MK8 version
by cfeniak

It took some playing around with as I've never used 123d design before, but I think I've figured it out. Posted it as a remix to the d-bot and your mk8 extruder, and I'll get a pic or two up once I have it mounted.

Thanks for the help!

What is the difference between mk7 and mk8?

Mk8 filament drive gear has a 9mm OD, mk7 has 12mm OD. Basically, a tradeoff between torque and grip on the filament.

The mk8 has been working pretty well, I haven't looked into any other drive gears

I've found that mk7 gives a better grip on the filament due to the larger diameter and the greater amount of surface area on the filament. For torque, I made a planetary attachment for my stepper motor.

Is it possible to make an mk7 version of your extruder? you can see cfeniak's mk7 extruder here: https://www.thingiverse.com/thing:292437

The issue with this is the mount interferes with the gantry if I have it on the side of the printer, but doesn't look good if I mount it on the front, and I'd rather not have it on the back for accessibility reasons.

Direct Drive Bowden Extruder for 20 mm extrusion
by cfeniak

Would there be any negatives to cut the v-rails to the 300x300 size and only use the 200x300 bed? If I ever decide to update to a larger bed, I just would like to have that option.

You could if you wanted to, as long as you put the 300x200 bed toward the back and leave the extra room at the front you wouldnt need to change endstops or firmware dimensions. You would need longer belts. The only downside is the bed would be a little front heavy but you could move the Z motors forward a little bit to try and keep it balanced.

May 10, 2016 - Modified May 10, 2016
MoshiBin - in reply to h8tebringer

That's very close to what I'm doing now. I actually have a 300x200 heated bed, but 300x300 aluminium bed and 300x300 piece of buildtak. Not sure how to mount that 300x300 alu bed on the 300x200 heater but I'll figure something out. If you go with everything 300x200 but 300x300 frame you can just mount the bed with the 300mm edge facing you, and move the bed mounts closer. You'll probably also need to tweak the firmware.

Edit: Maybe also move endstops?

I tried to load my ramps board this past weekend but i cant find the marlin.ino file. Any suggestions? Thanks

Download D-Bot_Marlin.zip from the thing files page, unzip, open the D-Bot Marlin folder, then the Marlin folder, then open Marlin.ino

I dont know what im doing wrong ,but the Marlin.ino file is not to be found. I'm wondering if they have reconfigured the way marlin is layed out

Its just an Arduino file in the zipped folder

I have been planning on building a CBot for about 6 or 7 months now. I've had most of the Rails and parts for the build for quite a while.. had some problems with my printers and a heavy workload and finally I've gotten around to printing the parts. Kind of glad I waited because Carl reworked a lot of the parts to make them more robust and that is good because my build is going to be 12 by 12 by about 30 inches I think.I have settled on doing the dual offset screws on my Z axis.
On the CBot Extrusion calculator it mentions that I might have to lengthen the horizontal extrusions 20 to 40 millimeters if I'm going to use the offset so there stepper Motors will clear bed.
Do you have a more exact measurement of how much I need to extend the width of my cbot? Thanks for all the great work

My bed is 12" wide so you can look at the lengths I used for the Dbot frame

Do you run your parts fan and the extruder heatsink fan always on at 100%? Would it be better for the extruder heatsink fan to be powered directly from 12V instead?

The heatsink fan is on 100% already, it is connected to the 12v input. The parts cooling fan runs according to firmware, powered off of the D9 terminals

That's what I thought. The electrical diagram shows the heatsink fan and parts fan connected to D9.

Only the part fan is connected to D9- which is switched by the controller, D9+ is always on

The electrical diagram shows the extruder heatsink fan and parts fan red and black connected together, and both are connected to D9.

Look again

Oh, right you are. Switched negative. Sorry, should have had a closer look!

I have parts on order, looking forward to building this, it is a wonderful design. Thankyou so much for sharing.

Are you still working on the build guide? Any updates coming?

Build guide will be done this weekend, I hope

Right in time for my build this week supposing I get my SSR in.

:D

Thoughts about using a lightweight geared extruder (titan + pancake stepper) instead of bowden?

It's definitely worth a shot, I didn't want to do direct drive because of the motor that would be needed but I noticed in Tom Sanlanderer's Titan review he used a pancake stepper so it's definitely possible