PETG layers are super rough

Question

I own a spool of PETG and I have been having major print quality issues: layer offsets, chunks of 3d print strewn across the buildplate and other things. I traced these effects to a single culprit: rough layers. I don't know how to fix this. I haven't had this issue at all with all of my other PETG filament colors. And the buildplate height is just where it needs to be, so why is this happening?

Print settings

Layer height: 0.23 mm
Extruder: 235 °C
Bed: 80 °C
Retraction length: 6 mm
Retraction extra restart length: 0.3 mm
Z-Hop height: 0.25 mm
Base print speed: 45 mm/s
Extrusion ratio: 106%

I am using Flash print. I dont know where to find "combing in my print settings" @R..GitHubSTOPHELPINGICE — X Builder, Apr 08 '22 at 18:15
Go a little warmer. Maybe 242. Also, that retraction number looks okay if you have a bowden setup, but it's way too high if you don't (1.5 is a better starting number) — Joel Coehoorn, Sep 09 '22 at 14:14

score 0 · Answer 1 · answered Apr 06 '22 at 21:39

You are probably over extruding, this causes an excess amount of filament causing the mentioned problems. PETG is softer than PLA, so the extruder teeth grip deeper into the filament. This smaller diameter causes too much filament flow. Try to decrease the flow modifier for this spool of PETG.

score 0 · Answer 2 · answered Sep 09 '22 at 14:17

Go a little warmer. Maybe 242.

Also, that 6 mm retraction number looks okay if you have a Bowden setup, but it's way too high if you don't (1.5 is a better starting number).

Finally, there are those who disagree on this point, but I only change my extrusion from the default 100% when I notice issues on specific prints. Ultimately, the extra 6% extruded material has to go somewhere, and it's likely contributing to the roughness.

PETG layers are super rough

Print settings

2 Answers2