PETG Threads Pulling Off
So I’ve been printing with PETG successfully for quite some time, but I’m currently running into an issue that I am hoping someone can give me some insight into.
The current parts I’m printing look fine on the exterior, but the part in question has an internal thread that is deforming. The individual lines are pulling off the model as they shrink. I am using Prusament PETG. I started with Prusa Slicer stock settings for this material. I have also tried the following:
-fans up to 80%
-fans down to 15%
-temp up to 260
-temp down to 230
-extrusion multiplier down to 0.90
I live in sunny South Florida, so the printing environment is a warm 75f. I didn’t think an enclosure would help with PETG, but wondering if it could help. Any advice on what to try next?
RE: PETG Threads Pulling Off
Also adding in, filament is thoroughly dried at 65C. Again, being south Florida, I’ve learned my lessons about humidity and PETG is always dried.
RE: PETG Threads Pulling Off
Seen similar with internal lines on a spherical surface where the innermost layer pulls away as the filament cools and shrinks. Perimeter wall thickness in relation to extrusion width and overlaps are critical and affect it hugely as does print order. Rounded thread crests and roots help, rather than sharp edges. Easiest fix is probably some light manual supports in the thread area.
RE: PETG Threads Pulling Off
What layer height and speeds are you using? At the apex of the threads what's the overall hang angle? Can you add the file for use to look at?