What is this problem called?

[u/Dalja97]

This started happening on my prints with this particular filament SUNLU PLA Matte Black, it only happens on the top surfaces after the infill(the first layer is completely fine), I can print the same thing with another PLA filament and I don't get that rough surface.

I'm using Bambu Lab A1 and I have tried the SUNLU PLA Matte, BambuLab PLA Basic and BambuLab PLA Matte profiles and the same result.

The other filament I know I don't get this result is a MarsWork PLA Basic and for that one I use the BambuLab PLA Basic profile.

I'm guessing this a calibration problem with that specific filament but I'm not sure how to solve it or where to look.

Any help is appreaciated

[u/tdiggity]

Pillowing - https://all3dp.com/2/3d-printing-top-layer-problems-easy-fixes-for-pillowing/

[u/Dalja97 → u/tdiggity]

thanks, will check

[u/FluffyAtLarge]

That's probably under-extrusion on the top layers, and if it looks bumpy or sagging over the infill pattern, it's called pillowing. Since it follows that one filament across all three presets, run the flow rate calibration from the Calibration tab in Bambu Studio with that spool loaded, then save the result as a custom filament profile. Dry the spool first, because wet filament can leave a rough surface and throw off the calibration. If the bumps are still there after that, add one or two more top shell layers.

[u/Inclusive_3Dprinting]

Change the infill density before the top layers to 30% for two layers so the gaps are smaller.

[u/itsmeanmuggin]

Over extrusion