@craftygeek, as far as fans go for filament cooling, I'd picked up a pair of generic 40mm ones... I'm guessing they put out 4cfm each. But since I'm running a Volcano nozzle that has over 3x the volume output of my rep1 (who's cooling fan is around 8cfm), my prints aren't getting cooled enough.
Figured I'd go big, so have a pair of these on order:
http://www.ebay.com/itm/121440135582
20cmf each. Not sure, may lift my machine off the ground, but I figured in my case I need to get a lot more airflow to cool down the 1mm nozzle worth of plastic coming out.
For cooling the Rumba board stepper drivers, the standard ones I mentioned above seem fine so far.

 

If those fans are anything like the ones we have in some of our servers, you better order some ear plugs too.

 

@Elmo Clarity : I may have gone too big on the fans, but I figured I don't have to drive them at full power. May as well have a big gas pedal if you need it though.... This is all just an experiment, right?

@Carl Feniak : Thank for those links, I'll look into that. Maybe it'll help with the extruder stepper temp issues I've been having.

Print temp: Yah, 250 is waaaaay (too) high for PLA, totally agreed. On my rep1 I can do 195->210 normally depending on the filament. I've been doing a ton of print testing on this new bot though, and I'm finding if I print lower than 250 (based on my 1mm Volcano nozzle @ 45mm/sec) I won't get good layer adhesion: My prints turn into Slinkies when done. My guess is that the filament, at time of extrusion from nozzle, may not actually be 250, based on extrusion speed. If I use a lower temp, the filament is much more opaque, and just won't stick to the previous layer. From 250-260 it gets nice and translucent and happily sticks to the stuff below it. If I drop my print speed down I can lower my temp... but who wants to print slow In fact I've tried going up to 60mm/sec, but even at 260 deg I start loosing layer adhesion again. Can you daisy-chain volcano's together?

Basically, I'm learning that printing with a big volcano nozzle is a totally different experience than a normal .4mm, so everything I knew about temps and settings is sort of thrown out the window and I need to figure it out all over again. Very little info on the web I've been able to find... so it's all just trial-and-error right now...

 

Thanks for sharing all your volcano wisdom AK Eric, there is not much info on the interwebs about how to print with it. This should give me a big leg up when I get my volcano setup.

 

Will be interesting to see how it prints: I'm starting to notice the shake on mine, with the toolhead that high up there (based on my 2' build height): I'm currently trying to figure out ways how to both bolt mine to the wall and the table its on: Just 'holding firmly onto the frame' while printing lessens the shaking substantially, so I think a wall mount should help quite a bit.

 

Mine is pretty solid now, I added two rails below the gantry sliders. I also contemplated acrylic walls to stiffen / and insulate. I had never heard of the bolt it to the wall route until I got into lurking on the delta group. Jetguy did add diagonals to his 4' cube coreXY.

 

Looks an excellent build I have skimmed through all the material to find the cost of parts to build . Could you help with a rough price please . In US $ is ok and I will convert to the poor AUD .
Cheers

 

I have almost all of my parts in and the total will be under $600. I didn't always go for the cheapest parts, just shopped around and sourced from various places.

 

Ive been using a smoothie board with mine and im having some print issues. Any of you smoothie guys mind sharing your config so i can compare it to mine? FWIW building this thing has been a blast and i'll try to post pictures of mine relatively soon!

 

I finally got my parts from robotdigg. Let me tell you, $5 for "expedited shipping" and it took over 3 weeks to get the handful of parts. Next time I'll just pay extra to get them domestically.

Turns out with this linked system I don't have to do any sort of counterweight or anything to keep the bed from falling down. I used an 848 belt, 1x 20T, 2x 40T pulleys anticipating that I'd mount the drive motor in the back, but it was too crowded back there so I moved it to the front. I'm going to order a longer belt to get the lead screws more toward the back. Gizmo Dorks changed their formula for the fluorescent blue color now so it is a darker blue which I do not like as much. They say it glows more in UV light, but I haven't tested it yet.


The 40T 8mm bore pulley just sits on a precision shim sitting on a F608ZZ flange bearing in a modified version of Carl's motor mount. The mount doesn't need to be this big but I fail at 123D and can't seem to figure out how to scale it down, it keeps telling me I can't push/pull the surfaces.


Wiring is starting to get organized, at least the smoothieboard is mounted. There's a Raspberry Pi running Octoprint mounted on the back side, powered with 5V from the Z max endstop header.


I came today not to post pictures, but to ask a dumb question: What do I attach to my filament spool to attach it to this nice spool mount? I just have a screwdriver jammed in it, but I bet there's some sort of nice spool holder I can print, right? Halp!

 

@CapnBry

Here is a spool holder I hacked together from parts of other spool holders. There are lots of them out there. Just have to find the one you like.

I have a question for you though. You say you are using a smoothie board, which I am using too. You also have OctoPrint hooked up to it. Have you played around any with the web stuff on the smoothie board? I haven't yet but wanted to find out what others think of it who have played around with it.

 

Thanks guys, I already have printed and attached the "C-Bot Roll Support" from Carl's design so I was looking for the piece that mates with that instead of just a generic spool holder. I'm really spoiled by my i3's spool holder which is a frame with F608ZZ flanged bearings on the bottom that hold any size spool I've used so far, unwinds with incredibly low friction, and never has pulled off sideways.

The webui on the smoothieboard is a novelty. You can use it to do some basic movement, home an axis, type a one-line G-code command (with response too, like an M119 endstop query) and tell it to print a gcode file already on the SD card. Uploading a gcode file through it will remind you of a 1995 MODEM because you literally get like 10KB/s. Uploading a couple megabyte gcode file takes several minutes.

OctoPrint has the same functions but also has the integrated GCode viewer so I can do a quick spot check of the output before I print. I also have OctoPrint doing my slicing (via Slic3r on another machine) so I upload an stl file and I have my gcode in about 12-20 seconds. The downside is that I can't load multiple objects onto the build plate at once, although Slic3r now supports uploading to OctoPrint directly from their UI. The webcam is a nice addition too to be able to be sitting on the couch and check on the print.

 

Carl, question on the Z-bar ends that connect to the vertical rails. Which side should the slotted holes be on? The inside or outside? Or does it not matter? I'm hoping for does not matter or inside.

 

Thanks. I had just taken it apart to move the lead screw nuts to the arms. Didn't think about which side the slots should be on. Just made sure they were on the same side. They weren't before I took it apart. Just didn't want to have to do that again.

 

You bet! As you can see I just removed the motor screw holes, changed the hole to be 22.1mm for the bearing and 25.3 for the flange. Thickened the top so it would be the same thickness as the bearing and sloped the inside bit so it can print without support. The bearing part can easily be 5-9mm slimmer in every dimension so I was trying to press it in but after about 10 minutes I decided that the extra 10 cents worth of plastic wasn't worth my time. The part would be a little stronger if it were smaller but I tested the first one I printed and it can really take a lot of ton of force before breaking down so not a big deal (the ears crack off first, so not a catastrophic failure).

Sorry about having to upload a ZIP, the forums won't take a 123dx file!

And now I see what everyone was talking about with the "cone" for the spool mount. I thought everyone was referring to a solid cone used solely to prevent the spool from falling off. Now I see it is a cone-shaped hub with bearings! I've printed off a couple and that takes care of that. Thanks for pointing me in the right direction.

 

Wow that's incredible attention to detail. When I went to install the cones last night I realized that the design was not symmetrical and flipped the bracket over so the shim bit would contact the bearing race. Is I was putting the rod in I said "I'll need to get a shim for th... wait a second!"

That drive gear do you have on your extruder? I bought a cheap MK8 when I was buying all the other parts from China and I am getting slippage. I'm trying to figure out if the hobbing is just garbage (it doesn't appear to really be cutting into the filament at all) or the radius is wrong or I messed up the extruder design when I made the holes bigger to accept the quick disconnect fittings I had.

 

Yeah I've got a pretty hefty spring on there and I've got the force such that I have concerns about breaking the little arm off. I inserted a piece of virtual filament in the 123D model and it appears to intersect where the gear should be, but I need to take off the gear and measure it to see if it is right. It does appear to be just the filament slipping but it is hard to tell because it only slips a little at a time and the gear is so tiny it is hard to see if it is moving. The bearing definitely snaps back a bit. It still prints but it happens every 10-20 seconds when printing at full speed so I'm sure it is affecting the quality of the print. I just wanted to make sure we were using similar dimensioned gears and the model wasn't designed for like a 8mm diameter gear and I was putting a 6mm gear in.

I was thinking about building one of Airtrippers extruders with the load cell in it that can tell me exactly how much force it is trying to push. Seems like a fun little waste of time!

 

Are there additional 3D files/instructions for filament feeding system? I was looking through the C-Bot assembly guide and the list of files I have but I can't find anything.

Thanks for your help!

 

So here's a closeup of my "MK8" extruder gear which I got China-cheap.

It has more flat part than bitey part so I am guessing that's why my filament is slipping.