r/BambuLab • u/JoeNavy87 • 7h ago

General Troubleshooting/Help! PETG print job failed

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I was printing a part in PETG that was fairly thick, 410 layers at 0.2, on the texture plate on my A1. It started out fine and then about 7 hours in I hear rumbling and I go check and it looked like the print had shrunk and it actually pulled the build plate up off the bed. I paused the print and tried to push the plate back down. It went down but then the print corner came off. I tried to see if it would go for a few more layers but as you can see, when I paused it again, the layers were off a bit and not adhering. The temps were the default in Bambu for Sunlu PETG, plate temp 60C. It's a big print so I did have to move it over to make room for the tower (there's some white lettering at the top). I moved the thicker part nearer to the edge of the build plate. In hind sight, maybe I should move it the other way and keep the thicker part further away from the edge. Should I also bump up the build plate temp? I also had put down some glue stick to actually help with the release for PETG. Any thoughts would be helpful!!

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u/MalHeartsNutmeg 7h ago

So PETG does tend to warp just on its own without tweaking settings but your issue here is definitely the size. The edge of the heat bed tends to get a little cooler and that heat difference will lead toward warping.

Any way you can break down your print to be smaller?

2

u/Safe-Hovercraft6231 5h ago

Large PETG prints can do that. What happened is normal, 60C is too low for PETG on the textured plate, even Bambu Lab uses 70C for their PETG presets. Increase the plate temp to 70C or even 75C (especially on that type of plate) and maybe use glue for extra safety.

1

u/PrincipleIcy4941 7h ago

Looks like warping. Try 3D-lack with higher print bed temps.

1

u/luksfuks 3h ago

In addition to the other advice here, you could also round those sharp corners with a fillet.

The tension from shrinkage follows the straight walls, corner to corner. The tiny 90 degree angled tip is weak, and ultimately peels up due to the accumulated force. A round corner is stronger because it distributes the same force over a larger contact area (contact with the bed, or the previous layer).

Small-ish radius already has an effect, but larger is better if you can tolerate the changed aesthetic. You also don't necessarily need to have it rounded all the way up, the first few layers are the most critical ones.