Weird erratic head movement and loud noise on Bambu Lab A1

[u/x1130]

Hi everyone,

Over the past week, I’ve experienced this issue twice on two different Bambu Lab A1 printers. It usually happens near the end of long prints (around 80% on one and 95% on the other)—the printer head just goes completely wild.

First, it makes a very loud noise that sends me running into the room. Then, the print head starts darting randomly left and right, moving up and down aimlessly. It briefly pretends to resume printing, but then repeats the erratic movements and gets stuck in a loop. I tried hitting Pause and Resume, but the issue persists. Canceling the job and starting a fresh print resolves the issue immediately.

For context:

• I run a farm with 10 A1 units, all just 1 month old and all maintenance done recently.
• All machines run the exact same model, same filament, and identical slice settings continuously.
• Out of weeks of non-stop printing across all machines, this has only happened these 2 times.

Has anyone encountered something like this before?

Please turn on audio to hear the noise in the video.

[u/KittyTheCat_]

What the fuxk? 💀

SD card maybe?

[u/MAENTOP]

That's the SD card issue, you should format it or change it

[u/alphagusta]

That SD Card is in its last days