Vertical delamination with PETG HF

Bambu Filament and Accesories Filament
1

Hi everyone,
Just made few prints with the new Bambu PETG HF and faced unusual issues with vertical delamination on thin parts with 1.5-2.5 mm width. The first layers attached to the print bed seem OK, the delamination occurs in the upper part of the prints that are 6-10 mm high. Happened on both black and white HF filaments. For comparison I printed the same parts with Bambu PETG translucent that is stored in the same dry environment and no issues at all.
I’m using Bambu A1 mini with 0.4 nozzle and default 0.20mm profile for PETG HF

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2

Looks like you need some combination of Flow Dynamics [pressure advance] and/or Flow Rate calibration, for this filament, IMO. You may also want to triple check that those gaps are not in the actual design for that compliant spring mechanism featured on pics 3+4.

3

Checked the CAD and no gaps, confirmed by PLA print which is flawless. Will run the flow rate tests during the weekend, however so far every Bambu filament was running well with the default Studio presets.

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4

I usually get these types of defects on the inside of circles (outer wall) but I can not say that I am able to reliably replicate them.

Sometimes, extra drying helps but most of the time, I need to slow down drastically (25% of defaults or even down to 50mm/s).

I am also struggling somewhat with default PETG HF profiles in very specific scenarios (H2C, Engineering plate) and ecpect this to be due to detailed tuning which isn’t quite there yet.
:right_arrow:
So it may worth it to compare temps, max flow and cooling between the profiles for an X1 and your A1Mini or between the A1Mini profiles for PETG Transparent and HF for a quick fix.

:four_leaf_clover: & :crossed_fingers:

5

Thank you very much for your support, the hint with flow control was correct. Actually the issues disappear with the standard Flow Dynamics Calibration activated just before the print. When I do lots of prototypes, to save time I usually use this option only once after changing filament and the settings remain OK for the subsequent prints. This time I didn’t do it when changing from PLA to PETG. I’m sorry :see_no_evil_monkey:

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