Bed Leveling/Adhesion Issues for the Dual Extruder

Hey all, I just got a new bed from Snapmaker a few weeks ago and I’ve started experiencing some combination of problems related to leveling and bed adhesion (dual extruder). It’s been slowly getting worse to the point where I can’t print without problems. I’m not even trying to dual extrude most of the time, just get the the primary extruder to lay down a proper first few layers.

See attached screenshots for a better visualization. I’ve been printing pretty consistently with multiple brands of PLA at 65C and get consistently bad results. I can only guess that my calibration routine is wrong, but idk how. Here’s what I usually do:

  • Power on the machine and run a manual sensor calibration
  • Run z-axis calibration
  • Preheat the bed to 65C for 15 minutes
  • Run the bed level calibration
  • During the initial leveling, I will adjust the z-offset on the fly

The problem with the last step is that the level will be perfect in some areas (typically the bottom right corner relative to the perspective in the pictures) and then fail to adhere in other areas. This seems like a sensor calibration failure, is anyone else experiencing problems like this?

Check this out Bed Leveling - Revisited & Detailed

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Perhaps a stupid question: Did you clean your printbead thoroughly? I recommend giving it a wash with a wet cloth and dishwashing soap ever once in a while (of course using just a wet cloth to remove the soap again, and dry it off), and also Isopropanol right before printing.

I recently did give it a quick wipe down with ipa but I don’t actually wash it or anything like that.

I just came across a post of yours about the 11x11 calibration, I think my next steps will likely be that calibration and a washing. I’ll post back here when I try that, @nweolu’s post also gave me some good other good ideas. Thanks all!

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Very disappointed to see that there’s a firmware issue that prevents me from running G1029A. I abandoned the 11x11 calibration attempt but would love to get that working eventually. Unless I missed a resolution somewhere?

Instead I just reinstalled my heated bed as was discussed in the above post and gave the cover a good scrub + ipa treatment. Looks like my first layer, while not perfect, is adhering quite well! Seems like the heated bed is quite sensitive to installation issues.

Thanks for the link @nweolu!

That’s what worked for me, I think past then with a 1.14.x firmware: 11x11 calibration with heated bed possible? - are you saying this is not working anymore?

It didn’t when I just tried it, specifically the G1029A gives me an error something like “cannot run without 3DP”. Ie, the dual extruder is not recognized as a 3D printing module. Doesn’t matter what I set the grid size to, I can’t actually start the calibration even if I’m connected to the machine via my laptop. Based on what I’ve read on the forums, this is a dual extruder bug.

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Gosh! That’s stupid… so they really implemented their own levelling procedure for the dual head… Why??? I noticed that it has a different pattern, not spiral, but scanning lines… It seems they failed to add heated bed levelling to Marvin standard leveling procedure, or what? I’m not amused…

Yea, my thoughts on Snapmaker swing back and forth over issues like this. In general I love my machine and most aspects of the designs are great, but I don’t think they invest in proper software engineering and quality control. Those two areas seem to consistently disappoint through bugs or just lack of attention to detail.

Especially because this firmware bug should be an easy fix, it might even be something I could tackle since I have a software background (web dev, not compiled languages like C++ but still). I’ll probably take a look this weekend and try to compile a fix.

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All the credit goes to @Mxbrnr for his effort in writing the leveling guide.

As for the leveling, dual extruder is a different animal, I hope you will fill out a ticket with support to let them know it’s important to keep the firmware consistent - Support Ticket Form

Also, check this out - Dual Extruder: bed leveling with nozzle i.s.o. proximity sensor

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Yea, that’s the post I found that made me realize that it’s possible to make my own firmware modifications. It’s somewhat terrifying since that also means I can fry my device with a bad update, but very happy that it’s open and possible to dig around in the code.

Ticket filled, although not sure it’ll do much good.

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Back to square one. Re-installing my bed while it was heated worked for a a few prints, but issues have resurfaced and I’m now unable to print again even when I re-try the same calibration routine. My guess is that when I get lucky and get a good calibration, I can print for a while on it until it slowly gets out of calibration. This is deeply frustrating, I don’t understand why it’s so hard to calibrate the dual extruder. My print isn’t even that large as you can see from the screenshot.

I’m definitely going to pursue that 11x11 firmware mod, although I forgot I’ll be travelling this weekend so can’t work on it for a week. Does anyone have any suggestions for trying to analyze and collect data on my bed level? The octoprint bed leveling mod looks like a good solution even though I have no experience with octoprint.

Also, next up is to change my slicer to cura instead of luban. I’d be shocked if the slicer really made a difference here, but I also see people talking about how inadequate luban is so seems like I should at least try.

Truth be told that was my biggest problem with the dual extruder as well.

I am hoping it corresponds to the heat creep discussion, the plastic is not coming out of the nozzle as intended so it is not adhering correctly. This is not something I know for certain and is just a hope of mine. I have the parts for rebuild on order right now.

Alas, I am having another wave of issues I am working through right now and am hoping I can get them resolved before the rebuild kit arrives.

I dont know… to me it does not really look like a levelling/bumpy bed problem… From the foto you posted I’d do three guesses (but it is guessing I admit):

  • Your print sheet looks dirty - or are the grey-ish stripes glue stick for better adhesion?
  • You may print a tad too high still - I’d try going 0.05-0.1 mm lower
  • the infill does not connect to the walls/perimeters - this may be a sign of underextrusion. Did you do anything to E-Steps? For me with the DX, the factory value is spot on.

That said, I can say that the DX is currently a source of joy to me - at least when using it single nozzle (some dual nozzle projects ahead - hope I’ll not be back to frustration, but the repair kit with the new door is installed, so my hopes are high). Only issue is that since 1.15.17 firmware Auto-Z yields always ~0.3 mm too high calibration result, which I need to compensate on the fly via touchscreen.

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If you have an accurate straight edge check the bed for bowing. While uninstalling and reinstalling the bed and releveling will fix it temporarily, if the bed is bowed it will slowly lose it’s “software” level. You might find the center is up to 1mm lower than the edges.

  • Correct, out of desperation I tried applying purple glue stick. It’s been hard for me to visually determine if the issue is that the filament simply isn’t “sticking” to the bed or of the lack of adhesion is caused by the nozzle being too far away. As you can see by my answers below, I still believe this to be a bed levelling issue.
  • The print in the pic is already adjusted 0.5mm down, the maximum it can go. There’s likely calibration error on my part that requires the offset to be so large, but this picture still shows bed leveling issues IMO. As you can see, the rounded pieces to the left of the image do not adhere well, and the pieces to the right are too squished into the bed.
  • I know infill not connecting is an indication of a bad first level, but as you can see some pieces in the image suffer from the problem and some don’t which again leads me to believe that this is a bed levelling issue. If the bed was levelled properly, we’d see all pieces either lacking gaps or having gaps, but we see a mix.

And agreed that for the most part the dual extruder has been way better than the single extruder, but these instances where it just suddenly stops being able to achieve a workable bed level are very random and frustrating.

I should also mention that I’m using the original Kickstarter bed frame, but the linear modules have been replaced with the latest models. @Mxbrnr mentioned in their post that the new bed frames likely have a better tolerance so I’ll reach out to Snapmaker and see if I can get a replacement.

@chogardjr how do I check for bed bowing? Is it something I should be able to see visually or do I need a probe mod?

I should also mention that yea, I had to completely remove my face plate to stop the heat creep issue. Once I did that all of my clogging issues disappeared. I’d be surprised if that was causing the issues I’m seeing now, but I’m not experienced enough to say for sure.

You would need an official straight edge for checking flatness of a surface. If you have a metal ruler that might work well enough to show the difference. When I noticed this I starting researching solutions. Someone else on this site said they used linear rails (requires printing spacer between the bed and rail guide). I ordered the rails and had a difficult time printing the spacer accurately but once I got them right the bed is now completely flat and the adherence issues went away and haven’t returned. Like you I was overly frustrated and had turned my machine off for about 6 months until I seen the post about the linear rails. Try a search to find the original poster. He includes STLs for the spacers.

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Oh cool, I saw the post about the metal rails but wasn’t sure if it was really going to be a solution to my problem or not. Thanks for the advice.

One thing I just realized is that my quick swap kit is coming soon which may completely change my situation. I’ll still check for bowing today since I’m curious now but I might hold off on the linear rails mod if the quick swap kit somehow solves the bowing/levelling problem. Doubtful of course, but worth waiting.