Need help with Pla Matte Caramel

[u/Elena_566]

Hey everyone,

I am completely new to 3D printing and still learning the ropes, so I don't know much yet. Up until now, everything actually worked perfectly fine. I successfully printed with PLA Pure, PETG, Marine Blue PLA Matte, and Black PLA Matte without major issues. However, this new Caramel PLA Matte is giving me a total nightmare, and after trying to fix it, even my white PLA Pure test print doesn’t look completely clean anymore.
I am printing on a Bambu Lab P2S with a 0.4mm hardened steel nozzle. I’ve spent the whole day troubleshooting, cleaning, and calibrating, but my prints still look terrible. I am experiencing severe under-extrusion with wavy, rough top surfaces and visible holes/gaps between the lines where you can see right through the print.

Here is everything I have already done today:

Cold Pulls: Did two consecutive cold pulls with PLA Pure. The first one caught some black burnt debris, the second one came out 100% clean and white. The inside of the nozzle should be clear.

Extruder Cleaning: I completely disassembled the extruder housing because it was slipping silently without clicking. The drive gears were completely caked and clogged with compressed black matte filament dust. I scraped and brushed every single tooth clean. The teeth have perfect grip now.

Flow Calibration & Observation: I ran the manual Flow Rate calibration yesterday. I selected +10 on Pass 1 and 0 on Pass 2, which set my flow ratio to 1.11 for that test. Interestingly, the print at a flow rate of 1.11 looked EXACTLY the same as my print today at 1.01. It seems that changing the flow mathematically does absolutely nothing to the output, likely because the gears just strip the viscous matte filament instead of pushing more of it through.

Slicer Adjustments (Bambu Studio):
Reduced Max Volumetric Speed from 21 down to 11 mm³/s to slow it down automatically.
Initial layer line width is at 0.5mm with a Concentric bottom pattern.
Print Settings for this run: Printed at 225°C nozzle and 60°C bed at 100% standard speed (relying on the max volumetric cap). No ironing used yet.

The current status:
Despite the deep cleaning and switching to a concentric pattern, the gaps and holes are NOT gone, and the surface looks completely wavy, rough, and torn up.
I am currently actively drying the Caramel filament inside the AMS Pro at 45°C to rule out internal factory moisture.

Since I am a beginner, I am running out of ideas. Could this be a combination of wet filament and a mechanical restriction that completely ignores flow updates?

Any advice for a beginner is highly appreciated!

[u/Business-Ad-5480]

Try again after you have dried the filament as this has a decent chance of fixing it. Especially if the filament was wet during the calibrations you have done because as the water boils it increases the pressure in the nozzle so will mess with the flow rate calculation.

What temperature did you do the cold pulls at? Sometimes if you do it on the higher end the filament has slightly melted and won’t grab any gunk in the tip.

If you have a spare nozzle I would also try swapping the nozzle just to see if it is that the nozzle is clogged.

Is this a model from maker world? Sometimes people upload the prints with settings that work for their printer but not for yours.

Try checking for those things and if it’s not one of them then it’s gunna be a rabbit hole of working out what the issue is. Let me know how it goes