Doh! It looks like it's only 24 amps (12" x 12" Heat Bed - Heat Beds). I got it confused with a recommendation I read somewhere for heat bed watts/area and forgot that the output for this one is significantly less than that.

 

I have a 12x12" heated bed (MakerFarm) hooked up to 12v. Reading their specs, it sound it would pull something around 20 amps.
I've have my printed plugged into a kill-a-watt when it runs (which lets you track volts, amps, watts, etc), and when the whole machine is running (all electrics on 100%, fans, extruders, steppers, lighting, mainboard, etc) + the bed heating a full power, it hits maybe 4 amps, max.
To be safe when building it, I used 12 gauge wire to hook the bed to the power supply directly (it's all bang-bang). And it'll hit 60c (what I use for PLA) it 30-40 seconds. So there's no lack of power there.
I've always just wondered why it wasn't pulling the full amperage that was listed? I'm not complaining, but have always been surprised.

 

Yeah, that's the heated bed I have as well.

Is the 4 amps at 120 volts AC?

 

Which brings me to my next question.. Anyone have a favorite printable PC power supply mount?

 

just wonder how many of you guys rewire the maker farm 12x12 heatedbed using a larger gauge wire? the original soldered wire seems like a 16awg to me.

 

12 awg on mine, left it for now, should be good enough for the short run to my 10 gauge which runs to the power supply. But will keep an eye on it for the first few prints.... The IR cameras folks seem to have around here sure sounds tempting.

 

Yep: 120 at the plug that the kill-a-watt is plugged into. Power supply plugged into the kill-a-watt.

 

Finalized the painting of the print, and blogged the whole process for anyone interested:
New 3D Print: Maui

 

Yea i saw AK eric and you went for the path of replacing the wire to 10/12 AWG. Now i am wondering if i should do the same.. AWW i really hate soldering :s

IR cameras are cool toys but way too expensive for me..

 

Your kill a watt measured 4 amps with a 120V supply is equal to ~480W.
Your bed is 12V @ 20A = 240W
Your hotend is 12V @ ~2.5A = ~40W (assuming yo have 1?)
4 steppers are approx 5W each (someone correct me on this)
Other bits and pieces maybe 12V @ 1A = ~12W.
Add that all up, and you have ~312W.

Switch mode power supplies are maximum 75-85% efficient.
312 / 0.8 (80%) = 390W.

There are a few things that can account for the difference between 390W and your kill a watt measuring ~480W:
- You have another device consuming a fair amount of energy (second extruder?)
- Your PSU is less efficient than this (and would be quite warm)
- Your heated bed pulls slightly more than this?
- You have a short somewhere
- The kill a watt is reading apparent power (VA) and not real power (W)

 

AH, @Austin Seagers : That makes sense. Meaning, the 20A at 12v. I though they meant 20A as 120V, duuurrrr......
Super throughout explanation though, thanks!

 

@AK Eric
Are you using one of the "standard" hobby power supplies? I'm re-purposing an old PC power supply, but might switch to the hobby supplies if it's actually viable since the form factor is much more desirable. I had read that the little 360W ones didn't provide enough current for a 12" bed.

 

No worries man. Least I can do in comparison to all those blog posts!

 

I'm using a Corsair CX500 : 500 watts at 12v
Builder Series™ CX500
@sheffdog had recommended it to me when I started the build, and it's been running like a champ.

 

I did the same, but did the 600M so I had fewer cables hanging out and can tap what lines I want easier by buying the ends vs cutting the lines from the power supply or having a long run and then a plug. Ran the bed to 3 of the of 4 x 4 lines to avoid having a single smaller gauge wire pulling the amperage. Quiet and working like a treat!

 

So I've successfully modified my RAMPS board to run from my 24v PSU but I have a question to throw out there; Seeing as 24v fans are not nearly as common as 12v ones (I work at a PC repair shop) does anyone foresee any problems on running a UBEC Power Module such as this one here to run all the fans EXCEPT for the print fan (which will be kept 24v as it is PWM controlled.

Thoughts? Suggestions?

 

Ultibots has a nice selection of 24v fans in the most common 3D printer sizes, if that helps.

 

Lots of fine tuning left and a ton of cable management but, it prints like a champ! WHOOHOO !

 

I got my new Titan Extruder from E3D the other day and have been building a new carriage for it...



This is my final test print in PLA and low infill. Printing it now in PET-G so I can mount it up and actually try using it. I also have to modify the back mount as the motor is offset from Carl's design.

If anyone is interested, I can post the .STL files. And if you promise not to laugh at my OpenSCAD programming, I can also upload the .SCAD files.

 

I'd be interested in the scad file and if you don't mind I will incorporate it into my generator for both prusa and c-bot carriages.

Chris

 

No problem. Just fixing a fit problem I discovered when putting it on that I need to correct for. Will clean up the file some and send it your way.

 

Hello, Im new here so I hope this is not the wrong place or way to jump in.

Very interested in doing a C-Bot/D-Bot/variant build - it looks like just what I need as my next printer (first printer is Monoprice Maker Select/Wanhao i3).

I am trying to read through this forum to learn, but there is a lot here. Any way to jumpstart the info gathering a bit?

I am thinking of a build size of 300x300 or possibly 400x400, and in particular am looking to make it easily enclosable - one of the things I liked about this design is it seems like minor adjustments and it could be enclosed with all motors/electronics outside the enclosure walls (assuming walls had some small holes for belts and z-rods to pass through.

So, where do I start!

 

Few recent upgrades:

Designed a new fan-shroud for my volcano nozzle. Wanted to get a lot more directed air at it. Looks a lot like a crab-claw, or a smiley face from the front. Did a test 3dbenchy, and already see noticeable improvements in areas like the smokestack. Find it on Thingiverse.


I'd noticed my xy steppers squeaking lately. After inspection, I found that the torque of the belts was tipping them slightly off-axis, especially considering I have the Astrosyn dampers on them. Wrapped them each in a zip-tie to the frame and tightened it down to counter that pull. Squeaks gone, and it just sound 'beefier' now when running, and I see less deflection on the 'loose side' of the belts during direction changes.

Of course they're no longer isolated via the dampers, but those were probably overkill anyway.

 

The printer is back up and running with the new Titan Extruder. Just need to clean up the wiring now. Seeing a lot better results than I was with the Printrbot Extruder I had mounted.

 

I've been noticing that cooling from one side leads to quality issues on the side opposite the duct. Would your duct work for an e3d v6? I'm assuming the volcano heatblock is larger

 

Yep, I've noticed the same issue with single-side cooling only, which is why I came up with this.
I doubt it would work on the v6, since it presumably has a shorter cold-zone and hotblock: I had to measure & model up the whole hotend\gantry in Maya to build this out, to make sure it fit correctly, since it's so close to the build platform & hotend itself. There's maybe 1-2mm of vertical space between the base of it, and the tip of the nozzle.
That being said, anyone is welcome to digitally 'moosh it into place' and test on their v6 setup.

 

Has anyone come up with a dual blower solution for the C-Bot?
Something like this (Thing 384688):

 

Slightly off topic but still relates to my C-Bot; I'm looking to control my 24v PSU much the same way I do the ATX one on my Kossel. Just put an AC relay on in front of the PSU? Mechanical or SSR?

 

I would recommend a mechanical relay for this. SSR's when off, still let a very small current through.

 

To be honest, I would not do this as my first build. It's not a *difficult* build, but it is one where you'll need to figure out a lot of things yourself, and it seems nearly everyone deviates at least a little from the reference build. If I had not already built a kossel from a kit I would feel hopelessly lost in the minutia of standard 3D printer parts. If you *do* decide to build this one, I would warn you to carefully consider whether you really need that large of a bed. I went with a 300x300 build, and I found that just going a little smaller (say, 300x250 or 300x200) would have saved me a lot of money. At 300x300 you'll have to buy a more expensive PSU, a large bed with a relay switch, and a more expensive build plate, not to mention the extra V-slot extrusion length (those things aren't cheap).

That said, everything you need to get started is in the files section or in the thread. I would suggest reading through it all before making your decision.