Issues with new CBot i3 clone

I just got a CBot i3 clone and after the assembly, I'm running into issues in trying to get it up and printing. Their Tech support is challenging in that they are in China (of course) and I'm in central US, so getting with them is a challenge. After submitting a support case, it ended up with a sales manager who wanted my skype ID for their tech, but with the time differential, will be a challenge.

Anyway, initially, the problems were the auto level feature seemed to be missing from the menus and it didn't seem to be recognizing that there are two extruders, as in the 'prepare' menu, under 'move axis'. But when I told it to 'auto home', while I don't know if it placed the nozzle in the proper location for 'home', it went to the axis ends and learned its limits, then placed the nozzle tip a hars width above the build plate - as the setup instructions said, so that it is just barely touching the tape. Auto home seemed to work perfectly. But when I tried to print, it's like it forgot the Z lower stop and was trying to drill for oil or something and drive the nozzle into the bed and started trying to print.

They sent me the firmware, which best I can tell is 'standard' Marlin firmware, version 1.0.0 RC2, according to the bootup splash screen. After dealing with the initial arduino compile issues (libraries, and then the way it's written, newer versions of the Arduino IDE don't like some things - the only one I ran into was "'fpos_t' has a previous declaration here" as I found that v1.0.6 didn't have an issue with that and after getting and using that version, it compiled no problem), I loaded it to the controller (which is this controller) and now have bigger issues. The menus still don't show two extruders (it does and did show two hot ends) nor the auto level option, and when I tried auto-home, that was totally broken. I did just discover that the axis are inverted (In the 'move axis' menu, when I told it to move the Z axis +5mm, it moved down instead of up), so that's probably an easy fix if I can find the right place in the sketch.

For my future knowledge, the controller has plugs for -X, +X, -Y, +Y, -Z & +Z. All of the '-' connectors are used for the end stops. Would I be correct to assume that this means that it's possible to have end stops at both ends of the axis?

That being said, does anyone have any tips/tricks for getting this printer up and working right? While the issues with the kit and iffy tech support are frustrating, in the end, building the kit and dealing with its issues and fixing them should leave me with a better understanding of how it all works.

Edit: Found and fixed the axis inversion issue. Auto home now works right.

Edited 1 time(s). Last edit at 12/29/2017 12:31PM by Cougar281.

I did some more tinkering and adjusting, adjusted the travel values in the firmware so that I was able to move the X end stop so that the nozzle would be at the end of the plate when it hit it, not way off the end, and it wouldn't try to travel to far in the other direction and jamb up. Did the same for Y & Z.

After some more tinkering, I somehow managed to get a decent print. It started off rocky, but since it wasn't trying to drill through the tape and bed, I let it go to see where it went. In the beginning, it was having feed problems, which I think are because the nozzle was too close to the bed, so the material had nowhere to go - once it got a little higher, it started laying down material pretty good. It seemed to go a little sideways towards the end though, when I wasn't looking. The layers Look pretty good up the sides until it got to about 1mm from the top, then it kinda went sideways, and the top isn't very clean. This was with the PLA they included with the machine, so who knows on that. That could be part of the problem, but might as well use the free stuff until I get it to the point of it reliably not trying to drill through the bed, then I'll put a new nozzle on (I'm sure getting dragged across the build plate didn't do it any favors) and maybe try some of the good PETG filament I have.

Any ideas why it seems to be intent on trying to drill through the bed, even though the end stop switch stops it just before it touches the bed and when I 'Auto Home' it, it leaves the nozzle just under .7 off the bed?

Edited 1 time(s). Last edit at 12/29/2017 03:36PM by Cougar281.

So here's what I've been getting so far with the prints. I did two prints of an object that turned out essentially identical, and similar in stature to how the below cubes turned out. They first items had a similar 'bell' at the bottom. The cubes printed nearly perfect once they got up past a handful if bottom layers, and in the cubes cases, they printed essentially perfect at the top. Where my first prints went sideways was, best I can tell, when it transitioned to top layer. I can't imagine why that went sideways while the cubes printed near perfect until the end.

Here are the images - printed at 205C and 215C, no bed heat (I read that bed heat with blue tape and PLA = adhesion issues - and that seems about right) otherwise, every aspect identical. I have two more printed at 210 and 205, but there's really no discernible difference between them. ll four cubes, best I can tell, are largely identical, despite the different print temps. They're about .2-.3mm smaller on the X & Y Axis than they should be (At the top - at the bottom they are a bit bigger than the 10mm they should be), and about .7 smaller on the Z. It seems to me like for some reason, something - maybe Cura, maybe the firmware, maybe something else - is having some sort of issue with the top and bottom fill, as that's where it seems to be showing issues - but the layers between the top and bottom fill seem to be pretty decent.

215C



205C



Truth be told, what I'm using right now is the free stuff that came with it. It wasn't sealed (plastic was punctured), so who knows how long it had been open to atmosphere and how much moisture it may have absorbed. That could be part of my problem. Or it might not be. But I'd like to get it as 'dialed in' as I can before I move over to the better, sealed PETG filament. I'd rather waste the 'free' stuff working out issues not related to filament before moving over to the better stuff.

Edit: here are my first two prints. First on the left, second on the right. On the first, I peeled,scraped off the failed portion and found nearly perfect printing underneath. The second, I peeled part of it away.


I should probably note that I'm using Cura 15.04.6 rather than the 'latest and greatest' because I'm toying with the idea of using an Octorpint with the printer, which only suports Cura up to 15.04.x apparently.

Another edit - better images of a cube printed at 220C:



Edited 4 time(s). Last edit at 12/29/2017 09:04PM by Cougar281.

You have to raise the z-endstop until it doesn't crash onto the bed while printing. It actually doesn't matter how well it behaves while homing, there might be some probe offsets in firmware you have to live with. ( unless you want to overwrite FW with your own setup )

Depending on the probe switch you got, the homing result may vary a lot. Too much for PLA on cold blue tape. Be prepared to do some babystepping each time you start a print. I suggest using a better probe. My I3 printer has seen four major improvements:

Clamping down the frame to a 16mm MDF board
Replacing the linear bearings with IGUS drylin bearings
Manually level the bed ( no half assed "will do" settings )
Adding an inductive Z-probe

Now I can slice a part, start the printer and leave it alone.

Thanks - that's helpful - I would have thought that if the homing was right, the printing would have been based off that, but guess I was wrong. I actually have an inductive Z probe and have gone back and forth between that and the NO/NC mechanical switch. The inductive probe is currently hooked up. Personally, I'm not wild about where it is, 70mm behind the nozzles, but it is what it is for now. As far as leveling, the auto level would be helpful, but at the same time I've also spent time tweaking the bed to get it as close to level in relation to the nozzles as possible.

Clamping it down to a sheet of MDF is a good idea - I'll have to do that. That certainly won't hurt the rigidity, and will prevent any movement of the build plate in relation to the rest of the machine. The rail that the plate rides on has about half a business card thickness of 'seesaw' movement in it. I might have to take it off and remove a tiny amount of material from the extrusion and then clamp it all down to a piece of MDF.

I'm not against firmware changes. Since it's already running Marlin, it probably wouldn't be too difficult to switch to the latest V1.0 release, if not V1.1. Truthfully, I've already learned a little about the firmware from my tinkering and fixing what broke with the version they sent me. I'm guessing that most, if not all of the critical variables are in the 'configuration.h' file? Since I have their firmware and have fixed what was broken to where it works again, I have a baseline with all the settings specific to this printer as set up.

On the prints, any thoughts as to why it's printing the way it is - seemingly just fine for the 'main' section, but the top and bottom (moreso the bottom with the cubes) aren't 'quite right'?

So for what it's worth, I re-printed my first prints, but sliced with Cura 3.0, vs the 15.04.6 that it had been sliced with before. When I looked at the layers view (after the fact) in Cura 15.04.6, it was 'wonky'. The same view in 3.0 looked proper. Granted, I printed it this time with PETG vs the PLA in the initial prints, but I suspect that if I were to reprint with PLA but resliced with 3.0 vs 15.04.6, I strongly suspect that the results with PLA would be similar or the same as that with PETG.Does anyone have any input?

PETG is another beast. It could be filament No.1, but it has it's issues too. It loves to stick at the nozzle, if you haven't dialed in the first layer height perfectly.
You have to print slow and still see blobs occasionally.
My advice, learn to print with PLA. It took me almost one spool, before I understood the slicers and printers do's and don'ts. That's a learning curve everyone has to follow.

Well, while haven't printed a whole lot, mostly testing with small things like 1cm calibration cubes and such, and with the PETG, the prints have been coming out pretty good. Take the knobs - slicer issues aside, the PETG one I'd say came out much better than the PLA ones - the layer quality seems much better. My problem has been adhesion for the first layer. Once it gets past that first layer or so where it has the adhesion issues, the rest comes out nice. The knob had some 'peel up' on one side that you can see, but other than that, it came out pretty good. I might need to try printing on something other than blue tape.