I started with two motors wired in series. This keeps the power draw on the driver down so it thinks it is only running one motor. I ran some experiments with my bed where I ran it up and down fixed distances each way. Then variable distances but would still finish where it started. I put a level on the bed and after running this for awhile, I could see a slight tilt to the bed. Saw this after every run. So I have switched to the single motor and belt. Either way will work.

I started off using 24v, mainly for the bed. Had problems getting the bed up to temperature using the 24v connection. The heater supported 12 and 24 and by running the 24 on the 12, it heated up a lot faster, but the power draw through the cables worried me. I could feel them getting warm (using 16 gauge wire). On my Printrbot Simple, I switched to using an AC powered silicon heater. That thing heats up fast. I switched to an AC one on the C-Bot and glad I did. I have switched back to 12v for now since I don't need the 24v for the heater anymore.

I will be interested in finding out how that Flex3Drive works out. I like the idea but the cost is a bit out of the budget for now. Was thinking I might use one on a delta printer I am working on.

 

I couldn't find an AC one that was 12x12 lol, at least not anywhere within a month of me. I am super excited about the Flex3, its going to be several weeks before I get it tho, he has a long lead time. I will keep you in the loop on how it works.

I may look at belt driven Z, I am really trying to make this printer as repeatable as freaking possible.

Well here goes another plate of parts, crossing my fingers that this spool makes it through.

 

I'm on spool #3 and will probably hit #4 before I finish this thing. But then again, I'm going for the slowest build time ever.

 

Yeah. They all come out of China it seems. I got mine from Keenovo. Took about 2 1/2 weeks for it to arrive. If you do go that route, check prices on both eBay and Amazon. The one I bought for my Printrbot was half the price on eBay vs Amazon. But the one for the C-Bot was cheaper on Amazon than eBay. All the listings were from Keenovo too. Guess the price fluctuates based on the day they list it.

 

Holy hell how have you used that much plastic? I am at least 2/3 of the way done and I've not even killed one spool yet. Printing at .2 with 70% infill.

 

Ha! They're indeed 1kg spools! I burned up a lot testing the generator, making parts for my i3, now printing a metric ton of wire chain links. Plus I like my infill for structural parts.

 

I am estimating that I will use almost 1 kg dead on. I started printing individual parts but once I was confident that my new extruder was killing it and I had the settings locked in I started dumping whole plates of them on there. Right now I am printing 4 brackets for the Z-axis, two lead screw captures, 2 corners for the bed and an XY endstop mount.

 

I started using Nylon for structural parts, I swear once you get it working its unreal. I was going to do all these in nylon but I couldn't source enough and didn't want to wait. Plus nylon is an order of magnitude more expensive than the PLA I get from Microcenter.

 

You are a gentleman and a scholar. Thank you for the information. I have these lovely 5x8 couplers lying around but the 5x5 ones are already on their way. I could not find the spider ones in 5x5 but oh well.

How are YOU syncing the Z-motors?

 

I do enjoy a good PLA, but for structural PETG is my favorite now that I've got it dialed in. Would try nylon except I don't have a thermocouple in my v6 blocks nor in the volcano.

 

I love PET+ from MadeSolid but decided against it for this build since I plan on slowly replacing the PLA with Nylon anyways.

I don't have a thermocouple in my E3D either, although I may go to one since the especially since the Azteeg has the hookups ready to go. I print Taulman 910 @ 245 but I have to go pretty slow.

 

Any openscad experts want to help me fix my awful awful fan duct in the generator?

I am thinking about half or quarter circles around the nozzles. Currently I have just a rectangle pointing 5mm below the nozzle and offset 18mm from the nozzle tip. Works great for the side the fan is on, but completely misses the back and it shows in the prints.

I need ideas and perhaps some help with the trig.

 

So you would leave both motors driving the axis (serial or parallel?) and then lock them together so that if one turns, the other turns.

 

The only downside I encountered when swapping to the front\back leadscrew option was that for whatever reason, that front leadscrew\acme nut would really squeak when the bed was raised. Was... odd.

What's interesting is, now that I've switched to the RADDS/Repetier, the squeak is gone. Didn't do anything different to my bed setup in any way.
Now that I think about it though, the only other difference was that I was using (via the Rumba/Marlin) two DRV8825 drivers to power my dual-z steppers separately. With RADDS, I'm using a single SD6128 driver to power them both. Food for thought.

I personally like the front\back setup because it requires nearly no new hardware: just a cutoff you probably already have to run across the front of the cantilevered bed, plus some corner brackets (I 3d printed them) to hold it in place. So if you'd already built your bot, you can make that change without having to invest any extra cash or wait on shipping. If you're building the bot from scratch you have more options of course, but I'd probably do it the same way again if I built another one.

 

I am going to be using SD6128s as well, and I was leaning towards Repetier, I really liked that firmware but I was using it at a time when I didn't know how to calibrate my printer and so I switched to a version of Marlin that was a lot closer to being dialed in, now I am running Marlin because almost everyone else that has this printer is and helping them with config settings and what not is a lot easier when its what I use.


I am also looking at Sailfish since ... well..since I can.

 

If I was to make a guess I would go with a firmware problem here, otherwise I totally agree with you.

The nice thing is that I have the motors and the screws, so I can get it set up and then figure out if/how I want to change it.

One thing that seems interesting to me is the idea of using a single stepper to drive a drive shaft that in turn drives 2 worm gears. I am NOT a mechanical engineer, I am a software engineer. So why wouldn't this work / why hasn't it been done?

 

Like basically linking two of these, but connected to a stepper. Its actually basically what we are doing now, except we are turning the power transmission 90 degrees which would allow us to connect two lifts with a physical steel shaft (or even a flexible one?)

ActionJac MJ-20-UR 5:1 | Nook Industries

 

ahh, eff it, I am buying a through shaft stepper and playing with this.
what do you think of this?
STP-MTR-17060D | Dual Shaft Stepper Motor: NEMA 17, 125 oz-in hold torque, 2.0 A/phase

 

I am looking, but havent seen that yet. The offset wouldn't be that much depending on how I drive the leadscrews. Still looking for some 90 degree power transmission stuff that will work.

125oz/in? I was like...yah...that should work.

 

So it looks like the BOM was updated yesterday with new calculations. I'm about to bite the bullet and place an order, but I *really* want to get this right since shipping is not cheap. For a 12x12 bed with 500mm lead screws mounted on the side, this is what I got from the spreadsheet:

X4 480 mm <-- front/back, top/bottom horizontal stationary pieces (2x 1m extrusions)
X1 466 mm <-- the back/Z moving piece
X1 506 mm <-- the top/XY moving piece (1x 1m extrusion cut with piece above)
X2 480 mm <-- top sides (1x 1m extrusion)
X2 460 mm <-- bottom sides (1x 1m extrusion)
X4 650 mm <-- legs, gives some flexibility for hotend length and mounting (2x 1.5m extrusions)
X2 445 mm <-- bed support
x1 520 mm <--offset motor mount option (1x 1.5m extrusion cut with piece above)

So it looks like 5 1m extrusions and 3 1.5m extrusions, plus probably an extra 1.5 in case I screw up. Does this look right? Have I missed anything? Should I go with a smaller lead screw?

 

Give me a minute, I will update my cut calculator with the new dimensions, it does a pretty good job getting the right lengths

 

Are your calculations different than the BOM? If so, what accounts for the difference?

 

Spiff, check this out.
C-Bot Cut Calc

You put in your dimensions and it finds the most efficient way to cut the pieces given your desired extrusion length. What I have not done yet is figured out how to make it mix extrusion lengths to get the MOST efficient solution. That is going to require some linear math that I just haven't had the time to write yet (I just started this yesterday) but I am working on it!

According to this you can go by with 6 x 1500 and 1x500 and end up with about 700mm of slack, if you wanted a bit more slack then make the last one a 1000 and you get 1200mm of slack and it would be long enough to cut any of the pieces again if needed.

Just another tool to help you, I had similar questions so I wrote myself a solution