AMS Filament Backup Not Pausing Print

Bambu Lab AMS Troubleshooting
1

I’ve been printing on an X1C with an AMS for a couple of weeks now, and for the most part everything’s been great.

However, I’ve been having a recurring issue - my AMS will detect that filament has run out on a spool, and successfully transition to another spool of filament, but will not pause the print while doing so.

This leads to the printer not extruding any filament for an extended period of time while still lowering the bed as if it was, then resuming extrusion in midair, causing spaghetti to form. I’ve had a couple of timelapses show this happening in exactly the same way.

https://i.imgur.com/QfpXyDU.gif(image larger than 4 MB)

I mostly print using SUNLU PLA+, on their original plastic spools. The transition in the GIF is from SUNLU PLA+ to SUNLU PLA+ 2.0, but this has happened with both spools being exactly the same.

Is there a setting I’ve missed to prevent this from happening, is it a sign that something is wrong with my AMS/printer, or something else?

I haven’t caught this live yet, but I’ll be trying to keep a closer eye on the printer in the future.

2

Weird. Do normal color changes work properly?

3

Yeah, that’s the weird thing. Multicolor prints work fine - I’ve printed several models with different colors for text and they’ve all come out just fine. It’s just filament backup that does this.