"Hole" in first layer infill
Hello everyone!
I got my mk3 a few weeks ago and in that time, I have only ever gotten one good print (a calibration cube). Sadly, I can't even reproduce that anymore.
What I get are first layers where there is a giant scar through the exact center of the in-fill as well as inconsistent "sticking" of the filament against the bed. Here's a picture of what I can see:
Some things I've tried:
So... I am very very much running out of ideas. I also admit that perhaps some of my attempts were not done completely thoroughly but the consistency of my issue is just ridiculous. I submit this evidence of the absurd consistency (each one of the boxes are separate runs):
I know this looks like a z calibration issue but nothing I do seems to change much regarding that center ripping. My suspicion is that the bed is not level and the mesh leveling isn't quite working right... I plan to flash the firmware (again) soon, just to see if that makes a difference. But any suggestions here would be greatly appreciated as I'm completely out of ideas by this point (and ready to rip all of my hair out :P)
Thank you for your time!
-Josh
Re: "Hole" in first layer infill
Josh, there is a cool octopi plug-in created by a member of this forum that will give you a visual representation of how your bed is leveled. If Pinda is a zip tie from nozzle and you did all calibrations then my guess is bed adhesion. Have you tried cleaning with warm water + dish soap and/or acetone?
Re: "Hole" in first layer infill
What's with the tape? probe should have closer to 1-2 mm clearance (from the bed not the tape). What does you auto-first layer cali look like?
Re: "Hole" in first layer infill
IMHO Live Z is way to high and try without the tape - you do not need that for PLA on PEI. PLA on PEI just works awesome
Re: "Hole" in first layer infill
Thank you for all the replies!
Regarding the tape, it was just one attempt I did to see if it would change anything at all about bed adhesion. It had roughly the same result as without the tape but I have since removed it.
Last night I flashed the firmware to the newest Release Candidate as it seems to have a bug fix to improve accuracy of the pinda probe. When I get home from work I plan to factory reset and then completely recalibrate everything and see if that improves anything. If it doesn't I will also run a mesh bed leveling calibration (there was a thingiverse print which helps determine how to calibrate the mesh settings manually).
I know it seems like a Live Z issue but the more fundamental problem is that it does not seem to be accounting for mesh leveling correctly. If I live adjust the z so the center portion can print, then it seems to fail extruding elsewhere (presumably because it's too close). But lets see if the upgraded firmware + complete recalibration makes any difference at all.
@gaston.d3 - Thanks for the suggestion! I'll definitely check it out, that sounds very promising.
Re: "Hole" in first layer infill
Hi Josh,
I would suggest to even do a factory reset after the upgrade and to NOT do a temperature calibration of the PINDA sensor directly after the upgrade/factory reset. Try it with the uncalibrated PINDA first.
Start with the center of the bed. The 1st layer has to be perfect and repeatable there before you try to influence the outer regions of the bed.
Re: "Hole" in first layer infill
Soooo... I did a complete factory reset + recalibration. Tried to run a live z adjust before temp calibration and after. Nothing has changed 🙁 which is incredibly unfortunate. I took live z all the way to the point where it causes the print to be completely ruined, then up a bit. And even when it's just above that point, it still has the center tearing pattern. I will keep researching but I feel like it's got to be a hardware issue. Maybe something with the extruder. Will update if I find anything.
Re: "Hole" in first layer infill
One other test that I did last night was rather interesting. I preheated the extruder and then went to "move axis -> extruder" and cranked it up to 140mm and watched the output. It was very very obviously not consistent. For the most part it extruded well, then after a while it randomly didn't, then it extruded well again. I'm starting to think it may be the extruder assembly which is causing all of my problems. I will look at taking it apart later and see if there's any obvious clogs. Maybe I'll replace the nozzle while I'm there too (as I have a bunch of spares).
Re: "Hole" in first layer infill
Quick update - I think I found the problem.
After inspecting the extruder assembly, I realized the bondtec filament gear was very very loose. Looking closer, I realized the shaft which holds the gear in place was not installed correctly. Also unfortunately, I think the piece I am using is broken so I am ordering a replacement of the "Extruder Idler". I'm 99% sure this is the problem though as it explains a lot of what I was seeing. Basically, I think the filament was occasionally slipping which caused poor first-layer adhesion which caused all the weird patterns and inconsistencies.
Thanks for all the help everyone! Once this replacement arrives in a few days, I'll install it and see if it resolves the problem.
-Josh
Re: "Hole" in first layer infill
Quick update - I think I found the problem.
... bondtec filament gear was very very loose ... replacement of the "Extruder Idler" ... Once this replacement arrives in a few days, I'll install it and see if it resolves the problem.
I'm curious ... was that the issue?
-- Clint Goss