Getting dark banding when going from dark to light color

Bambu Lab A Series Troubleshooting
1

Hello. I was hoping someone can please help me out here. I’m getting dark banding when going from dark to light color. My model has text on the outer wall of my model. I can normally print this just fine with various colors. I’m using Bambu Black (basic) and Bambu Ice Blue (matte) combination for the first time. I’m getting a dark banding all the way around the model in line with the black letters - and only in this area. I’ve seen lots of other people with this issue and the resolution is normally changing the flushing volume or the order of colors. None of these is working for me.

Here is the issue. You can see the black band all the way around the area:

banding
banding942×700 92.5 KB

Settings:

15% Gyroid infill
0.2mm standard quality
Turned off “flush into object’s infill”
turned off “flush into objects support”

I set very high flushing volumes (since the auto setting doesn’t seem to be helping):

flushing-volume
flushing-volume499×566 57 KB

Here is the filament color sequence:

color-sequence
color-sequence811×503 77.3 KB

Any idea how to fix this? I’m using a ridiculous amount of flushing volume so I’m really surprised I still have this band showing. I’m currently at a loss for how to get rid of it. Any help would be greatly appreciated!

Thanks!

2

Some darker colour stuck in the toolhead? Is it worth running a print in the lighter colour to flush the nozzle or a cold pull? Maybe try a nozzle swap if you have a spare?

3

After searching around, it sounds like really dark colors can sometimes be troublesome to purge completely from the nozzle and “ghost” on the lighter color. I found that the following settings helped me in this case (didn’t entirely solve, but made it better):

  • switched from newer purge “rib” tower back to original and made it extra long to purge more filament
  • Changed print order to “infill” first before walls (and made sure it does inner wall before outer wall)
  • Changed wall loops from 2 to 3
  • updated filament purge volume for black from 30mm to 250mm
  • Made sure the color ordering was from light to dark (although I don’t think this setting actually matters in my case)
  • Set flushing volume to max at 900 for any blue to black (and vice versa) color transitions
  • Turned off flushing into infill or supports

I tried creating my own purge tower object that was a lot wider and bigger, but couldn’t get it to work properly, so I abandoned that approach.

Yes, this uses a lot more filament, but I was running out of ideas and this combination of settings definitely helped.

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4

You can try a different black filament vendor, especially a black PLA-CF. Generally they don’t go as aggro with the dye when the CF is also contributing to the blackness.

5

  • Sounds like classic pigment carryover from black to light—especially tricky with high-contrast colors like Bambu Black and Ice Blue (matte). Even with high flushing volumes, I’d suggest trying a few things:

  • Try reordering the colors, so the lighter one prints first if possible. Going from dark → light tends to leave more residue.

  • Maybe re-enable "flush into infill, at least for the first few layers. Turning it off completely might be hurting more than helping in this case.

  • You can also manually tweak flushing volumes per color transition in Bambu Studio only boost it for black → blue, not globally.

  • If your model doesn’t have much infill/support space, try turning on a wipe tower temporarily just to confirm it’s a flushing issue.

  • Also, matte colors (like Ice Blue) tend to show banding more than gloss ones, so that could be exaggerating it visually.

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