Why does the printer "change filament" when it already have the correct one?

Bambu Lab H2 Series
1

Hi

I have just loaded a PPS-CF filament into the printer, and edited the filament type to the correct setting, PPS-CF, so the printer has this filament loaded and knows what it is.

Then I load my design into Bambu Studio, sync the filaments and set the filament of the object to be printed to the PPS-CF that I just loaded into the printer, and start the printing.

Now, one of the first things the printer does, according to the Device status, is “Changing filament”. Why on earth does the system change filament when it already have the correct filamnet loaded and it knows it!?

2

I think it’s because it doesn’t remember the last filament and is purging the system, not really loading the filament. More like cleaning the pipes.

3

This is just part of the startup procedure. You can see it in the machine startup g-code of the printer profile.

M620 S[initial_no_support_extruder]A   ; switch material if AMS exist
M1002 gcode_claim_action : 4
M1002 set_filament_type:UNKNOWN
M400
T[initial_no_support_extruder]
M400
M628 S0
M629
M400
M1002 set_filament_type:{filament_type[initial_no_support_extruder]}
M621 S[initial_no_support_extruder]A

M1002 gcode_claim_action : 4 is what displays the “changing filaments” message. You can see it first switches to an “unknown” filament, then the actual one.

In practice, if the correct filament is already loaded, no actual filament swap should take place.

-Max

1 Like
4

You are correct the right filament should be loaded, especially vs the left. However the code presumes not everyone is as organized so, it presumes there is one or or not the right one.

It would be nice if you could tell it not to, but that is not the case. Many are new to the 3D printing.