TL;DR
- insert the unload filament G-code in Bambu Studio when the nozzle that is connected to the AMS is not needed for a while
- when printing with one AMS and the external spool
Problem
If one filament is not used for a long time during a print job many people face the issue that it fatigues in the PTFE tube. Especially if the filament is needed later on in the print that is a problem.
This is quite common when the second nozzle is only used for support interfaces.
My Test Precedure
-
material 1: black, external spool, material 2: white, AMS
-
test object (minimal working example):
- layer 1 and 2: only material 1
- layer 3: both
- layer 4: only material 1
- layer 5: only material 2
-
in Bambu Studio: add custom G-code for layer 4 (executed at the beginning of layer 4 / end of layer 3)
; ===== inserted lines =====
; pull back filament to AMS
M620 S65535
T65535
G150.2
M621 S65535
M620 S65279
T65279
G150.2
M621 S65279
- this is the unload sequence from the H2D’s end G-code
- source: Bambu wiki: Disable unloading and flushing to save filaments when printing the same material
Result
- Bambu Studio Preview showed the wrong color for layer 4
- but the print turned out as intended!
- after layer 3 the AMS pulled back the filament
- layer 4 was printed in black
- for layer 5 the filament from the AMS was reloaded
Caution!
- more than two colors
- I haven´t tested this with prints that use more than two colors yet
- but I would expect the expect the AMS to just pull back the filament and then feed the next color/material once it is needed
- more than one AMS
- this G-code probably tells all AMS units to pull back the filament, so I doubt it would work in that case.
- I can´t test this since I only have one AMS