Selects the filament feeder setup the U1 is using. The main thing that differs between setups is the preload length: how far the feeders push filament toward the toolhead when it is inserted. The stock value is 950 mm, which suits the U1’s built-in feeders. Setups that move the feeders further from the toolhead need a longer preload, or filament stops short of the toolhead.
To support longer paths, the preload_length upper limit in
klippy/extras/filament_feed.py is raised from 1500 mm to 2500 mm. This is
always applied. The stock default of 950 mm is unchanged, so it has no effect
until a longer value is configured.
Select the feeder setup via the Firmware Config web interface under Snapmaker Components → Filament Feeders:
| Option | Preload length | Use for |
|---|---|---|
| Default | 950 mm (stock) | U1’s built-in feeder placement |
| BIQU PopStation mini | 2000 mm | Feeders installed in a BIQU PopStation mini |
Selecting an option other than Default links a config file into
extended/klipper/ that overrides preload_length for both
[filament_feed left] and [filament_feed right], then restarts Klipper.
printer.cfg is not modified. If you downgrade to a firmware without this
feature, the link is removed automatically on the next boot.
Only select a non-default option with the matching hardware installed. With the stock feeder placement, a longer preload may push filament hard into the toolhead.
The BIQU PopStation mini is a filament storage and feeding station that sits under the U1, with the U1’s feeders moved into the station’s drawer.
BIQU’s setup guide has you SSH in, touch /oem/.debug, raise the limit in
filament_feed.py to 2500, and set preload_length: 2000 in printer.cfg.
Stock firmware updates overwrite these edits. With the extended firmware, skip
all of those steps and select Snapmaker Components → Filament Feeders →
BIQU PopStation mini instead.
If none of the options fit your filament path, leave Filament Feeders on
Default and create your own file in extended/klipper/ through
Fluidd/Mainsail (see Klipper Custom Includes):
[filament_feed left]
preload_length: 2000
[filament_feed right]
preload_length: 2000
Values between 600 and 2500 are accepted. Restart Klipper after saving.
Filament stops before reaching the toolhead: check that Filament
Feeders matches your hardware. If you use a custom file, check that it is in
extended/klipper/ and has a .cfg extension.
Klipper fails to start with a preload_length error: the value is
outside 600–2500 mm.