I’m running into a frustrating issue where the printer fully unloads the support filament in the middle of a print. It doesn’t break; it just pulls back out of the extruder, and the printer then pauses and waits for me to manually reload it. This is a big problem since if it happens during overnight prints, printer sits whole night without doing anything.
Specific to Support: This only happens when I’m printing ABS with Support material (tried both generic HIPS and Bambu Support for ABS). Standard multi-color prints with the same material work perfectly.
Not a Breakage: The filament isn’t snapping inside the tube. When I go to fix it, I find the end of the filament sitting right at the entrance of the extruder gears.
Hardware Swaps: I’ve tried switching hotends and swapping the support filament from the right side to the left. The problem persists regardless of which side is used.
Feeding Issues: My filament is dry, kept in an active dryer, and runs through a short PTFE tube on bearings. There is almost zero resistance, and the extruder is definitely grabbing it at the start.
Filament Quality: The material isn’t brittle and extrudes perfectly when it’s actually in the nozzle.
My Best Guess It feels like a logic error during the tool change. Instead of just retracting a little bit to switch tools, the printer seems to be performing a full unload command by mistake. Anyone having the same issue?
I noticed yesterday during a TPU print with PLA as support material, that after a couple of layers, the left PLA nozzle went back to the purge station and was seemingly doing a new dynamic flow calibration (wiggling a bit left and right over the purge station). Since it is connected to an AMS it just continued, and I have no clue if this was the similar behavior that you experienced.
I don’t know if this was caused by the firmware or the slicer though.
I once had the issue that the right nozzle commands got mixed up and feeding actually retracted the filament, had to powercycle and it went away. Also check by manually slicing mode that just the support material is sliced on the nozzle you want it if you dont change filament, also are your flushing volumes set to 0 on the nozzle this occurs ? ( i know seems kinda unrelated ) You could also try and use other filament as profile for testing, say petg or PLA save it as “support test” or something, put all your filament information in and see if it is indeed the support filament slicerside that causes this. E.G fool the slicer
I had some weird stuff yesterday with a Support for PLA and two colors of PLA. The support was on the left nozzle and it did a full purge but I suspected it was due to the nozzle being cold for so long since it only uses it for interface slices. It wasnt the first time it had to use the filament and the other two colors were on right side.