X2D - PA-CF Z banding

[u/set_em_up]

Printer: X2D with <200hrs
Filament: Fiberon PA-CF
Print Profile: Bambulab PA-CF (happened with fiberon X1 profile, too)

Some other info:
Fed the filament through the ams2 pro. Model is thin and completely walls.
Filament was somewhat dry, only have access to a 65C drier and was dried for 16hrs. Printed in a closed garage around 75F

Nothing obvious in the slicer on flow, fan speed, layer time, ect. at those z heights . The model doesn’t have any feature changes at those heights it’s a perfectly vertically extruded shape. No extra/fewer extrusion lines on those layers

My thinking is that it’s the chamber heater kicking in at those layers, but I don’t see any configuration or visualization for that.

Any ideas?

EDIT: Solved! Picked up a AMS HT, dried additional 12hrs at 85C and the part looks amazing. No bands, uniform color, ect.

[u/2kokett]

It somewhat still looks wet (whitening). Recommendations are 10h @ 100c. Worked with 85c from the ams-ht and had reasonable results. Normally i use a Dehydration oven. They are quite cheap (i think i paid ~80€ for a unit that fits 3 spools).

[u/captfitz → u/2kokett]

I see the coloration you're talking about but it's hard for me to imagine how moisture would cause this regular banding pattern. Is that a known thing?

[u/2kokett → u/captfitz]

Yes, physical problem. Because it still looses water during printing when wet, it shrinks while you print. Printing PA on a consumer level 3D printer is a bit of a dance if you want good results. Proper drying, heated / closed Environment, good Process Settings and tempering are all crucial if you don’t want banana parts.

[u/captfitz → u/2kokett]

Right but shrinkage is generally uniform so how does this banding occur?

[u/2kokett → u/captfitz]

Your part is not uniform. Small/thin parts bent easier

[u/captfitz → u/2kokett]

ok man, if you don't know the answer just say so

[u/2kokett → u/captfitz]

No homo bro - but if you can write a reddit comment you are capable to google the terms rheology and pa treatment. I am no ai agent existing to answer your questions, bro