I'm trying get the filament change command running on my printer but it does things I don't understand. When the M600 command is executed the printer pauses and parks the head but then does nothing more. I then must pull out the filament manually, insert the new one to the extruder, and when I click "continue" it does load the filament and the purge. I don't understand why it does not do the unload.
The Printer is based on a Ender 5 Plus but with a Micro Swiss Bowden Dual Gear Extruder and a BIGTREETECH SKR Mini E3 board with Marlin 2.0.9.3.
These are the values in the firmware:
#if ENABLED(ADVANCED_PAUSE_FEATURE)
#define PAUSE_PARK_RETRACT_FEEDRATE 60 // (mm/s) Initial retract feedrate.
#define PAUSE_PARK_RETRACT_LENGTH 6 // (mm) Initial retract.
// This short retract is done immediately, before parking the nozzle.
#define FILAMENT_CHANGE_UNLOAD_FEEDRATE 58 // (mm/s) Unload filament feedrate. This can be pretty fast.
#define FILAMENT_CHANGE_UNLOAD_ACCEL 15 // (mm/s^2) Lower acceleration may allow a faster feedrate.
#define FILAMENT_CHANGE_UNLOAD_LENGTH 680 // (mm) The length of filament for a complete unload.
// For Bowden, the full length of the tube and nozzle.
// For direct drive, the full length of the nozzle.
// Set to 0 for manual unloading.
#define FILAMENT_CHANGE_SLOW_LOAD_FEEDRATE 50 // (mm/s) Slow move when starting load.
#define FILAMENT_CHANGE_SLOW_LOAD_LENGTH 0 // (mm) Slow length, to allow time to insert material.
// 0 to disable start loading and skip to fast load only
#define FILAMENT_CHANGE_FAST_LOAD_FEEDRATE 58 // (mm/s) Load filament feedrate. This can be pretty fast.
#define FILAMENT_CHANGE_FAST_LOAD_ACCEL 15 // (mm/s^2) Lower acceleration may allow a faster feedrate.
#define FILAMENT_CHANGE_FAST_LOAD_LENGTH 680 // (mm) Load length of filament, from extruder gear to nozzle.
// For Bowden, the full length of the tube and nozzle.
// For direct drive, the full length of the nozzle.
//#define ADVANCED_PAUSE_CONTINUOUS_PURGE // Purge continuously up to the purge length until interrupted.
#define ADVANCED_PAUSE_PURGE_FEEDRATE 3 // (mm/s) Extrude feedrate (after loading). Should be slower than load feedrate.
#define ADVANCED_PAUSE_PURGE_LENGTH 50 // (mm) Length to extrude after loading.
// Set to 0 for manual extrusion.
// Filament can be extruded repeatedly from the Filament Change menu
// until extrusion is consistent, and to purge old filament.
#define ADVANCED_PAUSE_RESUME_PRIME 0 // (mm) Extra distance to prime nozzle after returning from park.
// #define ADVANCED_PAUSE_FANS_PAUSE // Turn off print-cooling fans while the machine is paused.
// Filament Unload does a Retract, Delay, and Purge first:
#define FILAMENT_UNLOAD_PURGE_RETRACT 13 // (mm) Unload initial retract length.
#define FILAMENT_UNLOAD_PURGE_DELAY 1000 // (ms) Delay for the filament to cool after retract.
#define FILAMENT_UNLOAD_PURGE_LENGTH 8 // (mm) An unretract is done, then this length is purged.
#define FILAMENT_UNLOAD_PURGE_FEEDRATE 25 // (mm/s) feedrate to purge before unload
#define PAUSE_PARK_NOZZLE_TIMEOUT 300 // (seconds) Time limit before the nozzle is turned off for safety.
#define FILAMENT_CHANGE_ALERT_BEEPS 0 // Number of alert beeps to play when a response is needed.
#define PAUSE_PARK_NO_STEPPER_TIMEOUT // Enable for XYZ steppers to stay powered on during filament change.
//#define FILAMENT_CHANGE_RESUME_ON_INSERT // Automatically continue / load filament when runout sensor is triggered again.
//#define PAUSE_REHEAT_FAST_RESUME // Reduce number of waits by not prompting again post-timeout before continuing.
#define PARK_HEAD_ON_PAUSE // Park the nozzle during pause and filament change.
//#define HOME_BEFORE_FILAMENT_CHANGE // If needed, home before parking for filament change
#define FILAMENT_LOAD_UNLOAD_GCODES // Add M701/M702 Load/Unload G-codes, plus Load/Unload in the LCD Prepare menu.
//#define FILAMENT_UNLOAD_ALL_EXTRUDERS // Allow M702 to unload all extruders above a minimum target temp (as set by M302)
#endif
