3D Printing Problem: PETG Over-Extruding Infill only? Help Please

[MandicReally]

So I am fairly new to printing but things have been going smoothly until quite recently. Since day one I have been using PETG to print as I intend to make car parts and wanted to learn the ropes with a material I could actually use long term. Only very recently I'm getting some failed prints due to a weird issue. I have been constantly tweaking to improve my prints but I have zero idea what could be causing this problem.

Namely when printing PETG, sometimes (only SOMETIMES), the Infill seems to over-extrude or peel up. It gets stuck to the hot end and smears around. Then I hear the nozzle and cooling fan ducts clicking off of it as they travel over the printed part after those globs cool a little. However the First layers and perimeters print beautifully. Zero blemishes or issues. It is just the Infill acting up.

I've tried tuning the print on the fly, reducing Extrusion percentage, raising hot end temperature, increasing the Cooling Fan speed, and baby-stepping the Z-Step. None have seemed to have any appreciable effect. I'd think Perimeters and First layers would be affected as well if it was something like bed level (which I recheck often). They are just fine though.

A few weeks ago I threw on a roll of PLA for some less important prints and it printed beautifully. Never skipped a beat. This weekend I switched back to PETG and got a handful of perfect prints out of. Then today I started a 5 hour long print, and it started to have this issue as soon as the infill began.

 

I've seen this called "Shoveling", and I guess that could be what I'm fighting, but none of the posts I've found online about it have been much help.

 

I'm running a basic Ender 3 with a handful of minor upgrades. It does have the Silent 4.2.7 Creality board in it, the issue was there before and after board swaps. The PETG Filament is "Dikale" brand from Amazon and like I said, SOME prints are fine. The first few dozen that I did had no issues. I was using Cura as my slicer but the last few prints I've switch to Prusa Slicer. The issue occurred with both Slicers.

 

[Levent]

Looking that print, I can see that you are over extruding everywhere. Are you certain that extruder is calibrated? If so, try reducing extrusion width (its under Print Settings > Advanced in PS and Slic3r).

[MandicReally]

4 minutes ago, Levent said:

Looking that print, I can see that you are over extruding everywhere. Are you certain that extruder is calibrated? If so, try reducing extrusion width (its under Print Settings > Advanced in PS and Slic3r).

I just recalibrated when I switched to PLA but haven't since being back to PETG again, I will run a calibration process again.

[Levent]

1 minute ago, MandicReally said:

I just recalibrated when I switched to PLA but haven't since being back to PETG again, I will run a calibration process again.

Try calibrating using lowest advertised temps of that filament. I had filaments that extruded significantly more at higher temps.

[MandicReally]

24 minutes ago, Levent said:

Try calibrating using lowest advertised temps of that filament. I had filaments that extruded significantly more at higher temps.

Just recalibrated, and by the calibration test I'm UNDER Extruding...  Tried it twice and got the same result each time.  I'll have to dial back the extrusion in Prusa Slicer and see what happens.