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Consistent PETG buildup causing crash  

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Fosstech AS
(@fosstech-as)
Member
Consistent PETG buildup causing crash

Hi, Im trying to print thin parts with 100% infill in PETG. The nozzle will always pick up some filament, deposit a blob in a random place, which it then crashes into causing print failure. It often leaves thick strings before moving on to the next instance, as if it wasnt retracting but extruding. Retraction is set to 1,6 mm. The rest of the settings are unchanged from prusa's. How do i prevent this buildup?

Printer is a brand new 2 tool XL. Bed adhesion is always great. Pla prints perfectly fine. It happens with both tools. Filament (add:north) is new, dried, and printed directly from drying box. 

Posted : 06/03/2026 7:45 am
Fosstech AS
(@fosstech-as)
Member
Topic starter answered:
RE: Consistent PETG buildup causing crash

I forgot to mention that i printed a calibration cube in vase mode to check extrusion multiplier, it was already perfect. 

Posted : 06/03/2026 8:14 am
Diem
 Diem
(@diem)
Illustrious Member

100% infill is almost always a mistake - why do you feel the need?

If it really is necessary small parts are better specified with a high number of perimeters so that it effectively becomes 100% without any infill.

What size nozzle are you using?  With 0.6mm nozzles you have to be extrmely disciplined about filament drying to prevent PETG stringing.

If you need more help save your project as a .3mf file

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

Cheerio,

Posted : 06/03/2026 11:17 am
Fosstech AS
(@fosstech-as)
Member
Topic starter answered:
RE: Consistent PETG buildup causing crash

The parts are around 2 mm tall, and varius wide shapes. The two millimeter height means just the top and bottom layers alone almost make it into 100% infill. Since its so thin I also need as much material as I can get to keep some strength. Im using a regular 0,4 mm nozzle. Unforunately I cant share the models. 

Im starting to think that since almost the entire part is solid infill, that it has to do with speed. Prusa has it set to 140 mm/s in their 0,25mm structural preset, even higher than regular infill. 

Posted : 06/03/2026 1:45 pm
Diem
 Diem
(@diem)
Illustrious Member

If you are using 0.25mm layers on a 2mm tall part try slicing with 4 top and 4 bottom layers.

Cheerio,

Posted : 06/03/2026 2:53 pm
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