Weird diagonal artifacts on new A1

Bambu Lab A Series Troubleshooting
1

Hi to everyone,

I have a strange issue with my new A1 replacement.
I’m in printing for a while with other printers, never had this kind of issue on a simple model like that.
I have just print an empty cube with 2 different PLA spools. One is a new Bambulab PLA basic purple but same issue.
What tests I have made without success :

  • change filament spool
  • check all axis, lubrification,belts etc…
  • full calibration
  • change seam position
  • change cube position on plate
    The weird pattern always occurs along X axis in one side when the hotend moves to the left as you can see on photos, the opposite side has a very light pattern almost invisible in some case, more visible on gray PLA than on purple.

IMG_20250313_202645
IMG_20250313_202645540×1200 88.9 KB

IMG_20250313_202701
IMG_20250313_2027011200×888 213 KB

IMG_20250313_202711
IMG_20250313_2027111200×983 194 KB

IMG_20250314_083543
IMG_20250314_0835431200×540 77.7 KB

IMG_20250314_144652
IMG_20250314_1446521200×927 161 KB

If someone has an idea of the issue and a fix, it will great.
Thank in advance

2

This comes from overextrusion and is diagonal because each layer shifts the thick spot forward slightly. So flow rate calibration would be the thing to try.

2 Likes
3

I don’t think so because

  • if I move the object on the plate, the pattern is different ( you can see on the last photo, the pattern is more regular than on previous pics)
  • it happens always on x side never on y side even if I change seam / retraction position. The seam is on a corner.
  • it happens with different filaments with exaclty the same pattern.
    For me, it seems to be a resonance or interference on x axis or hotend, but not the belt as it is not regular.
1 Like
4

Try slowing down the outer wall. Also, you need to tune the pressure advance.

1 Like
5

I am curious then, did you happen to measure the x vs y dimensions?

6

I will make it after resolving this issue with a cross calibration.
In fact, the main problem on Bambu printers is the accuracy in x/y dimensions.
I think to swap the X gantry of my old a1 to the new one to check if the problem comes from x motor/driver or hotend.

7

I can but if it was that, when I move the seams/retraction to other corner, it should change the side.

2 Likes
8

If the x axis was fine on the old one yes that would def be a thing to try.

9

I have swapped the toolhead (hotend + extruder + motor + linear bearing) and the artefacts have almost disappear ( very very less visible) so I think it is the linear bearing on x axis. I’m on the old mainboard + the old x rail+ old x motor and the new toolhead.

I will check yet with swapping to the new mainboard and teh old extruder motor (because the new is heating a lot).

A very big task to acheive. Unmount all the extruder to swap motor.

2 Likes
10

Now thats quick shipping and install!

11

What do you mean ?
It wasn’t quick at all…

12

I believe this is caused by over extrusion and wet filament. If that doesn’t work, run the calibration processes. And make sure you got the right filament type selected.

14

No it was the bad bearing and oil of bambulab !

15

Have you found the part that causes this problem?
I’m thinking of buying new parts.
Unfortunately, they don’t sell linear bearing.

16

Yes it was the X linear bearing and the bad oil of bambulab.
But I have other issues, the print are bad quality even with new bambu spool.
The layers are irregular as you can

bad-print
bad-print1920×2560 363 KB

IMG_20250508_133144
IMG_20250508_1331441920×2560 682 KB

see here :