MMU3 custom color change procedure ILO purge block
 
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etmidust
(@etmidust)
Member
MMU3 custom color change procedure ILO purge block

Background:

Core one with community MMU3 mod, and silicone wiper mod (with waste bin)

Question/Idea:

Is there a way to use the custom tool change gcode in the printer settings to park the extruder slightly off the front of the print bed and just dump what would be the purge blocks' worth of filament into the printed waste bin then wipe the nozzle on the silicone sock before resuming the print? I don't understand the gcode abilities enough to know if this is possible as an option or if it may need a custom post export script maybe?

Posted : 04/08/2025 2:39 pm
etmidust
(@etmidust)
Member
Topic starter answered:
RE:

Here is the custom tool change code that I got from a chatbot.
I am unable to test it soon, so dropping in case someone else has time and/or can see obvious problems prior to my testing.

; --- BEGIN MMU3 TOOLCHANGE FIXED PURGE USING FILAMENT OVERRIDES ---
G92 E0 ; Reset extruder
G1 Z{max(layer_z + 2.0, 3)} F720 ; Lift nozzle to avoid part collision
G1 X86 Y-14 F9000 ; Move to fixed purge position
G1 Z1.2 F720 ; Lower to purge height

; --- Ram & Unload using filament-specific values ---
G1 E-0.8 F1000 ; Soft initial retract
G1 E{-18 + filament_unload_extra_length[previous_extruder]} F1000 ; Ram with added yank
G1 E-{filament_unload_length[previous_extruder]} F{filament_unload_speed[previous_extruder]} ; Full unload
G4 P300 ; Dwell to settle

; --- MMU Tool Change ---
T[next_extruder] ; Switch to next filament
G92 E0 ; Reset E after new filament load

; --- Load and Purge with filament-specific length ---
M109 R{temperature[0]} ; Wait for stable temp
G1 E{filament_load_length[active_extruder]} F300 ; Load and purge
G92 E0 ; Reset E again

; --- Optional Silicone Wiper Mod ---
G0 X76 Y-18 Z1.2 F10000;
G0 X40 Y-14 Z1.2 F10000;
G0 X76 Y-18 Z1.2 F10000;
G0 X40 Y-14 Z1.2 F10000;
G0 X76 Y-18 Z1.2 F10000;
G0 X40 Y-14 Z1.2 F10000;
G0 X76 Y-18 Z1.2 F10000;
G0 X40 Y-14 Z1.2 F10000;
G0 X76 Y-18 Z1.2 F10000;

; --- Lift for return ---
G1 Z{layer_z + 0.6} F720

; --- END MMU3 TOOLCHANGE FIXED PURGE ---

This post was modified 2 months ago by etmidust
Posted : 04/08/2025 6:23 pm
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