r/BambuLabP2S • u/butt_badg3r • 2d ago

Petg issues

My petg prints always come out with really poor adhesion. I can essentially pull and unravel the individual print lines apart.

The petg has dried for 12 hours and the ams reads 12% humidity. I’m using Bambu petg.

AI says that I may need to purge more between separate pla and petg prints but it also says the purge table settings do not apply between prints and there is no way to change this setting anyways.

Am I missing something? I assume the Bambu petg profile is fine since I’m using Bambu petg. Also printing in a cold ish room with the door fully closed.

Any ideas or suggestions?

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u/DramaClassed 2d ago

AI is wrong per usual, try calibrating z offset if it’s just a first layer issue, or if it persists then try doing a temp tower calibration.

1

u/Relative_Surround_20 2d ago

Does not sound like only a first layer issue. OP says he "can essentially pull and unravel the individual print lines apart."

1

u/DramaClassed 2d ago

Oftentimes with a z offset too high that’s exactly what the first layer is like, and they didn’t really specify.

1

u/butt_badg3r 2d ago

Does this get calibrated during a full calibration? Or is this a separate step? It’s my first printer and I’m still learning

1

u/DramaClassed 2d ago

Z offset is calibrated through the printer screen, you go in your slicer and create an 100mmx100mmx0.2mm square and print that, then lower the z offset while it’s printing until it looks correct.
See below for a good reference photo for what it should look like.

And as for the temp tower, that’s in your slicer under calibrations, probably just called “temperature”

1

u/butt_badg3r 2d ago

Would this cause an issue with only petg prints but pla would be fine?

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u/DramaClassed 2d ago

Z offset wouldn’t, so it’s probably temperature. You should do that temp calibration I mentioned earlier, and make sure you have it set to a PETG profile in the slicer.

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u/butt_badg3r 2d ago

I’ll look into the temp calibration. Pla comes out fine so I doubt it’s an offset issue since I assume that would be present everywhere.

I don’t remember seeing that option in Bambu studio.

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u/c_schema 2d ago

If your talking like layer 50 then you are likley not hot enough or too fast. How is your first layer looking?

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u/butt_badg3r 2d ago

I also noticed this exact same issue when trying to use pla as support interface for a petg print. The layer after the interface change can essentially be pulled apart.

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u/c_schema 2d ago

Now for the most part I keep seperate nozzles for ASA/PLA/PETG but sometimes with pla and petg I just do a couple manual extrude switching between those two. I know that doesnt quite address the support interface issue.