Solved Massive under extrusion on bottom layer even with onboard slicer

So I just picked up a used C2 (after having an R1 for a few years and then not printing for a couple years) and am trying to get it set up. Made sure the firmware was up to date, ran both the rough and fine z offset tuning, and started printing. I was using Astroprint to slice, and realized it was setting the first layer at way too short (resulting in the chopped-up top layer indicative of that issue). So I threw the swatch STL onto a USB stick and let the printer slice it. I finally got a completed print, but as you can see in the attached image the extrusion was crazy low on the first layer. I'm using PolyMaker's PolySmooth at 210° extruder temp.

Could this also be a layer height issue? It seems so strange that the top of the print looks pretty decent but the bottom layer is like 50% under extruded. Any help appreciated.

 

So how would I go about adjusting the extrusion amount on the C2? On my old R1 I remember changing settings was modifying the Arduino project and flashing it to the board. I'm not familiar with what's actually under the hood of the C2.

The offset definitely doesn't seem too low. I'm new to this printer and re-learning the fine details of printing, but I've printed quite a bit before and if anything my z offset is a tad bit too high because that was also my worry. And if that was the case it would effect all the layers, not just the bottom one.

 

Yeah something is just not adding up here. I'm only seeing under extrusion on the first layer (as shown in the images attached to the OP), so I doubt calibration is the issue.

Does the C2 run an Arduino/RAMPS board like the R1 did? I've been out of 3D printing for so long I feel so lost.

 

Well that's... not a smart decision. I guess I'll do that though if something does die.

That's what I originally thought! But with both the z offset slightly high and super low I get the exact same issue. No, it's set to use no rafts or anything. Why is a raft the default option? Who the hell uses rafts anymore?

 

OK so I was giving the two swatch prints I tried a closer look and it's almost under extruding by EXACTLY 50%. I mean almost down to the pixel when looking at a digital picture of them. Could this be a stepper control issue? It's only happening on the first layer, which is just so freaking confusing.

 

Like I mentioned, this is with the onboard slicer. I haven't been able to get any other slicers to even work yet because there's some weird first layer height issue I need to work out. The z offset is set perfectly but when using an off-board slicer the nozzle drags through the first layer.

 

Sure, will do. I'm about to test upping the layer height using Astroprint to slice, and if that works it will definitely narrow down what the issue is. Will post startup code tonight.

 

Well. I started responding to this thread when the forum notified me of a new post. I followed Tkoco's steps to reset the firmware. It sure as hell looks like that solved the problem. I'm printing something now and except for a small area of slight under extrusion, it looks like it's working. I'm still going to post what I was going to post before though, in case anyone finds this in the future.

I started at .3mm and went up to .4 and .5 in the first layer height in Octoprint. Attached are the images of the first layer (or so) of .4 and .5mm. The .4mm photo actually has 2 walls around the outside, and you can see the layer height is perfect, but the print still fails. Then at .5mm you can see the layer height is too high, and failure. So it definitely wasn't a first layer height problem.

When logging into Octoprint for the first time it told me there was an update, and I installed/updated EEPROM Marlin Editor Plugin: 1.2.1. So it could have been that, or resetting the firmware that did it for me. I'm not sure which. Regardless, thanks Tkoco. I think I have this solved. I'll post an image of the print when it's done.

 

Yeah the firmware reset did help, but I'm still getting noticeable under extrusion on just the bottom layer (will have slightly more once I raise the z offset a bit as needed). I don't understand how the reset helped some but not all.

How do I get the startup code out of Octoprint? Via command?

 

I don't see any GCode labeled "startup" or anything like that, can you point me in the right direction?


Also, I added the airflow ducts published by Robo3D and just as it says may happen I'm having issues at the beginning of prints. It says to change the airflow settings so the fans turn on after 10mm of print height. How do I go about changing that? I know there are settings for that in external slicers, but like I've mentioned I've had bad luck with external slicers so far.