Help me solve A1 Z-Banding Mystery

Bambu Lab A Series General Discussions
1

a1_1_z_banding
a1_1_z_banding768×1024 229 KB

My A1 is about 2 years old and since several weeks a very nasty Z-Banding on very large objects has been introduced. Z-Banding problems are not unusual, even my P1S has some minor problems with it, but the Z-Banding my A1 started to do is extreme.

The wild thing is that it happens only on huge objects!

Here you can see a near perfect benchy printed with the same profile and same PETG HF as the other object.

a1_2_benchy
a1_2_benchy768×1024 347 KB

a1_3_benchy2
a1_3_benchy2768×1024 280 KB

I have also printed a 80mm tower and it looks almost perfect, no Z-Banding at all.

a1_4_8cm_tower
a1_4_8cm_tower768×1024 209 KB

What I have tried to solve it:

  • printing at a much slower speed
  • redone calibration
  • new hotend
  • new build plate
  • completely cleaned and re-oiled all 3 axis
  • retentioned belts on all 3 axis

Now I have run out of ideas and hope someone of you has an idea about what’s going on.

Thank you in advance!

2

Usually caused by larger horizontal internal structures shrinking as they cool, which pulls in the side walls for a few layers.

The larger the object, the larger the horizontal structures, and the more absolute shrinkage for the same percentage shrink.

3

If that’s the case, why only my A1 has this problem, and not my P1s.

4

The P1S has an enclosure, which keeps the air temperature higher. This reduces warping because the printed filament cools more slowly.