AMS Filament not extruding post flush. But works by itself!?

Bambu Lab AMS Troubleshooting
1

I have Inland filament in my printers AMS right now. A brown, black (HS), and a white. I’ve successfully printed entire prints before as a single color with all these filaments in their current position in the AMS, including some multicolor chess pieces (white/silver, black/gold).

All of a sudden now white, and only white, is acting up. And it’s only acting up for multicolor prints. Single white only prints work perfectly fine, infect I have one running now.

When doing multicolor, the purge poos are fine. Of course I have tons of samples, I’ll spare posting but they are quite big because of black → white or brown → white flush settings. The white sides are long enough where I’d be comfortable reducing it. But I digress, I didn’t change any factors in my flushing volumes.

One of my failed prints 3mf (7.2 MB)

PXL_20250207_155346104
PXL_20250207_1553461041920×1446 153 KB

As you can see in the attached image that the priming tower starts on the edge then doesn’t extrude anymore after that. Again. This is only for white as other colors start to spaghetti up.

Here is my modified “change filament” g-code that i use for my installed “scrubbler” (addition of an a1 pad for nozzle wiping) filament change gcode and the below modified section cut out.

G1 X80 ; shake to put down garbage
G1 X100 F5000
G1 X165 F15000; wipe and shake
G1 Y256 ; move Y to aside, prevent collision
M400

;================================================================
;===== Custom Gcode for P1S =====================================
;===== Scrubbler nozzle wipe start ==============================
;================================================================
G90 ; absolute mode
G1 X105 Y265 F30000; start position for wipe
G91 ; relative mode
; run snake pattern at max accelleration
G1 X-25 F30000
G1 Y-0.5
G1 X25
G1 Y-0.5
G1 X-25
G1 Y-0.5
G1 X25
G1 Y-0.5
G1 X-25
G1 Y-0.5
G1 X25
G90 ; absolute mode
G1 X165 Y265 ; return to start position
M400
G1 F3000 ; restore previous accelleration
;================================================================
;===== Scrubbler nozzle wipe end ================================
;================================================================

G1 Z{max_layer_z + 3.0} F3000
{if layer_z <= (initial_layer_print_height + 0.001)}
M204 S[initial_layer_acceleration]

Any help is greatly appreciated as white is such an important color to have working for multi color!

2

Unless you really need the tower I would try without.
Have no issues with multi colour prints without the tower.
For me the main benefit of the tower is the additional nozzle cleaning, which I use for fine details.

I had some problems with a filament similar to yours and nothing would fix it.
Funny enough all issues were gone when I had to swap that spool for a different colour.
Once back in the AMS it behaved as it should.
Can’t be sure but maybe it is just a hick up and assigning a different filament to then change back helps?

1 Like
3

Oddly enough this works. I don’t know why swapping a diff color in would work, even after I completely unloaded the filament and cycled the printer’s power before reloading it didn’t, but it did.

4

Sometimes it not the fixes that make us happy but those workarounds and totally unlogical things…
I gave up a long time ago assuming that standard solutions are always the best answer, we have to be creative at times…

5

The problem is back Specifically with white again and it’s a new spool!
This time it’s not going away. :face_exhaling:

I can confirm it is 100% the scrubbler’s gcode as it’s not occurring with the with original profile after testing this with over 10 different prints.

I will be looking in to this in a month or two, but for now, I’m just gonna use the default code.

For Matt coming back here in the future: Think about simplifying the code into the movements only and pushing it to just after the “wipe & shake” line.