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Stringing problem with PETG filament  

Stringing problem with PETG filament

Hello everyone,       BallSportsGear

I have been trying to print with PETG filament on my Prusa i3 MK3S printer, but I have a lot of stringing and oozing issues. The strings are thin and hard to remove, and they ruin the surface quality of my prints. I have tried to adjust the retraction settings, the temperature and the speed, but nothing seems to help. 

Does anyone have any tips or tricks to reduce or eliminate stringing with PETG filament? I have heard that increasing the travel speed and using a coasting feature might help, but I am not sure how to do that in PrusaSlicer. Any advice or suggestions would be greatly appreciated. Thanks in advance! 

Best regards,


Posted : 27/02/2024 11:21 am
Walter Layher
Honorable Member
RE: Stringing problem with PETG filament

Did you dry your PETG filament? This is the first step you should do with PETG, no matter if it is fresh out of the bag or not.

Posted : 27/02/2024 11:39 am
Noble Member
RE: Stringing problem with PETG filament

PETG (and also PCTG) is the worst of the common filaments in regards to stringing. It is probably impossible to print it without any kind of stringing but if everything works fine, the stringing is very minor and won't cause any surface defects. 

If you already tried retractions, temperature and speed, one more thing you can try is optimize the z-lift, if you have one. One can also try no z-lift at all. That increases risk of collissions but can help against stringing. 

The most important thing however: Dry your filament. 
It doesn't matter if its brand new, freshly opened, or not, perfectly stored in a dry box or not. Dry it again. And dry it long. Right before the print and then try your optimal conditions again. 

The wetter PETG gets, the worse the stringing becomes. If your PETG stringing is out of control, you  can't be paranoid enough when it comes to dryness of the filament. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 27/02/2024 11:43 am
Prominent Member
RE: Stringing problem with PETG filament

If at first you don't succeed, skydiving is not for you.

Posted : 27/02/2024 3:58 pm
Reputable Member
RE: Stringing problem with PETG filament

Your nozzle could be too hot.. dry dropping 10C.. I’ve also had stringing in PETG when my nozzle gets worn.. Are you using brass nozzle and if so, how old is it.. do you print filament with abrasives in it? (Wood, metal, etc). PETG generally prints very well on my MK3S+. 

Posted : 27/02/2024 9:28 pm
Brian liked