Perform a small extrusion prior to unload

Firmware/Marlin.h

@@ -496,7 +496,7 @@ void proc_commands();
 
 void M600_load_filament();
 void M600_load_filament_movements();
-void M600_wait_for_user(float HotendTempBckp);
+bool M600_wait_for_user(float HotendTempBckp);
 void M600_check_state(float nozzle_temp);
 void load_filament_final_feed();
 void marlin_wait_for_click();

Firmware/Marlin_main.cpp

@@ -3706,7 +3706,7 @@ static T gcode_M600_filament_change_z_shift()
 #endif
 }	
 
-static void gcode_M600(bool automatic, float x_position, float y_position, float z_shift, float e_shift, float /*e_shift_late*/)
+static void gcode_M600(bool automatic, bool runout, float x_position, float y_position, float z_shift, float e_shift, float /*e_shift_late*/)
 {
     st_synchronize();
     float lastpos[4];
@@ -3720,6 +3720,7 @@ static void gcode_M600(bool automatic, float x_position, float y_position, float
     int feedmultiplyBckp = feedmultiply;
     float HotendTempBckp = degTargetHotend(active_extruder);
     int fanSpeedBckp = fanSpeed;
+    bool cooldown = false;
 
     lastpos[X_AXIS] = current_position[X_AXIS];
     lastpos[Y_AXIS] = current_position[Y_AXIS];
@@ -3728,7 +3729,7 @@ static void gcode_M600(bool automatic, float x_position, float y_position, float
 
     //Retract E
     current_position[E_AXIS] += e_shift;
-    plan_buffer_line_curposXYZE(FILAMENTCHANGE_RFEED);
+    plan_buffer_line_curposXYZE(FILAMENTCHANGE_EFEED_RETRACT);
     st_synchronize();
 
     //Lift Z
@@ -3742,14 +3743,28 @@ static void gcode_M600(bool automatic, float x_position, float y_position, float
     plan_buffer_line_curposXYZE(FILAMENTCHANGE_XYFEED);
     st_synchronize();
 
-    //Beep, manage nozzle heater and wait for user to start unload filament
-    if(!mmu_enabled) M600_wait_for_user(HotendTempBckp);
+    if(!mmu_enabled)
+    {
+        //Beep, manage nozzle heater and wait for user to start unload filament
+        cooldown = M600_wait_for_user(HotendTempBckp);
+    }
 
     lcd_change_fil_state = 0;
 
     // Unload filament
-    if (mmu_enabled) extr_unload();	//unload just current filament for multimaterial printers (used also in M702)
-    else unload_filament(true); //unload filament for single material (used also in M702)
+    if (mmu_enabled)
+    {
+        // unload just current filament for multimaterial printers (used also in M702)
+        extr_unload();
+    }
+    else
+    {
+        // unload filament for single material (used also in M702)
+        unload_filament(runout? UnloadType::Runout:
+                        cooldown? UnloadType::Purge:
+                        UnloadType::Swap);
+    }
+
     //finish moves
     st_synchronize();
 
@@ -3798,8 +3813,8 @@ static void gcode_M600(bool automatic, float x_position, float y_position, float
     //Feed a little of filament to stabilize pressure
     if (!automatic)
     {
-        current_position[E_AXIS] += FILAMENTCHANGE_RECFEED;
-        plan_buffer_line_curposXYZE(FILAMENTCHANGE_EXFEED);
+        current_position[E_AXIS] += FILAMENTCHANGE_PRIMEFEED;
+        plan_buffer_line_curposXYZE(FILAMENTCHANGE_EFEED_PRIME);
     }
 
     //Move XY back
@@ -8133,7 +8148,8 @@ SERIAL_PROTOCOLPGM("\n\n");
 		float e_shift_init = 0;
 		float e_shift_late = 0;
 		bool automatic = false;
-
+		bool runout = false;
+
         //Retract extruder
         if(code_seen('E'))
         {
@@ -8191,8 +8207,13 @@ SERIAL_PROTOCOLPGM("\n\n");
 
 		if (mmu_enabled && code_seen_P(PSTR("AUTO")))
 			automatic = true;
+        if (code_seen('R'))
+        {
+            // Code 'R' is supported internally to indicate filament change due to a runout condition
+            runout = true;
+        }
 
-		gcode_M600(automatic, x_position, y_position, z_shift, e_shift_init, e_shift_late);
+		gcode_M600(automatic, runout, x_position, y_position, z_shift, e_shift_init, e_shift_late);
 
 	}
     break;
@@ -11728,7 +11749,7 @@ void restore_print_from_ram_and_continue(float e_move)
 	//then move Z
 	plan_buffer_line(saved_pos[X_AXIS], saved_pos[Y_AXIS], saved_pos[Z_AXIS], saved_pos[E_AXIS] - e_move, homing_feedrate[Z_AXIS]/13, active_extruder);
 	//and finaly unretract (35mm/s)
-	plan_buffer_line(saved_pos[X_AXIS], saved_pos[Y_AXIS], saved_pos[Z_AXIS], saved_pos[E_AXIS], FILAMENTCHANGE_RFEED, active_extruder);
+	plan_buffer_line(saved_pos[X_AXIS], saved_pos[Y_AXIS], saved_pos[Z_AXIS], saved_pos[E_AXIS], FILAMENTCHANGE_EFEED_RETRACT, active_extruder);
 	st_synchronize();
 
   #ifdef FANCHECK
@@ -11876,7 +11897,8 @@ void M600_check_state(float nozzle_temp)
 //! If times out, active extruder temperature is set to 0.
 //!
 //! @param HotendTempBckp Temperature to be restored for active extruder, after user resolves MMU problem.
-void M600_wait_for_user(float HotendTempBckp) {
+//! @return True if the wait involved a hotend cooldown due to timeout.
+bool M600_wait_for_user(float HotendTempBckp) {
 
 		KEEPALIVE_STATE(PAUSED_FOR_USER);
 
@@ -11885,6 +11907,7 @@ void M600_wait_for_user(float HotendTempBckp) {
 		uint8_t wait_for_user_state = 0;
 		lcd_display_message_fullscreen_P(_T(MSG_PRESS_TO_UNLOAD));
 		bool bFirst=true;
+		bool bCooldown=false;
 
 		while (!(wait_for_user_state == 0 && lcd_clicked())){
 			manage_heater();
@@ -11917,6 +11940,7 @@ void M600_wait_for_user(float HotendTempBckp) {
 					lcd_display_message_fullscreen_P(_i("Press the knob to preheat nozzle and continue."));////MSG_PRESS_TO_PREHEAT c=20 r=4
 					wait_for_user_state = 1;
 					setAllTargetHotends(0);
+					bCooldown = true;
 					st_synchronize();
 					disable_e0();
 					disable_e1();
@@ -11951,6 +11975,7 @@ void M600_wait_for_user(float HotendTempBckp) {
 
 		}
 		WRITE(BEEPER, LOW);
+		return bCooldown;
 }
 
 void M600_load_filament_movements()

Firmware/fsensor.cpp

@@ -620,7 +620,7 @@ void fsensor_enque_M600(){
 	puts_P(PSTR("fsensor_update - M600"));
 	eeprom_update_byte((uint8_t*)EEPROM_FERROR_COUNT, eeprom_read_byte((uint8_t*)EEPROM_FERROR_COUNT) + 1);
 	eeprom_update_word((uint16_t*)EEPROM_FERROR_COUNT_TOT, eeprom_read_word((uint16_t*)EEPROM_FERROR_COUNT_TOT) + 1);
-	enquecommand_front_P((PSTR("M600")));
+	enquecommand_front_P((PSTR("M600 R")));
 }
 
 //! @brief filament sensor update (perform M600 on filament runout)

Firmware/ultralcd.cpp

@@ -4473,7 +4473,7 @@ void lcd_wizard(WizState state)
 				lcd_display_message_fullscreen_P(_i("Now I will preheat nozzle for PLA."));
 				wait_preheat();
 				//unload current filament
-				unload_filament(true);
+				unload_filament();
 				//load filament
 				lcd_wizard_load();
 				setTargetHotend(0, 0); //we are finished, cooldown nozzle
@@ -5573,25 +5573,32 @@ static void mmu_cut_filament_menu()
 
 
 // unload filament for single material printer (used in M702 gcode)
-// @param automatic: If true, unload_filament is part of a unload+load sequence (M600)
-void unload_filament(bool automatic)
+void unload_filament(UnloadType unload)
 {
 	custom_message_type = CustomMsg::FilamentLoading;
 	lcd_setstatuspgm(_T(MSG_UNLOADING_FILAMENT));
 
-    raise_z_above(automatic? MIN_Z_FOR_SWAP: MIN_Z_FOR_UNLOAD);
-
-	//		extr_unload2();
+    raise_z_above(unload == UnloadType::Swap? MIN_Z_FOR_SWAP: MIN_Z_FOR_UNLOAD);
+    if (unload == UnloadType::Purge)
+    {
+        // extrude slowly
+        current_position[E_AXIS] += FILAMENTCHANGE_UNLOADFEED;
+        plan_buffer_line_curposXYZE(FILAMENTCHANGE_EFEED_PRIME);
+        st_synchronize();
+
+        // relieve leftover pressure
+        current_position[E_AXIS] += 0.1;
+        plan_buffer_line_curposXYZE(FILAMENTCHANGE_EFEED_PRIME / 2);
+        st_synchronize();
+    }
 
-	current_position[E_AXIS] -= 45;
-	plan_buffer_line_curposXYZE(5200 / 60);
-	st_synchronize();
-	current_position[E_AXIS] -= 15;
-	plan_buffer_line_curposXYZE(1000 / 60);
-	st_synchronize();
-	current_position[E_AXIS] -= 20;
-	plan_buffer_line_curposXYZE(1000 / 60);
-	st_synchronize();
+    // retract & eject
+    current_position[E_AXIS] += FILAMENTCHANGE_FIRSTRETRACT;
+    plan_buffer_line_curposXYZE(FILAMENTCHANGE_EFEED_RETRACT);
+    st_synchronize();
+    current_position[E_AXIS] += FILAMENTCHANGE_FINALRETRACT;
+    plan_buffer_line_curposXYZE(FILAMENTCHANGE_EFEED_EJECT);
+    st_synchronize();
 
 	lcd_display_message_fullscreen_P(_T(MSG_PULL_OUT_FILAMENT));
 

Firmware/ultralcd.h

@@ -186,7 +186,17 @@ extern bool bFilamentAction;
 void mFilamentItem(uint16_t nTemp,uint16_t nTempBed);
 void mFilamentItemForce();
 void lcd_generic_preheat_menu();
-void unload_filament(bool automatic = false);
+
+
+enum class UnloadType : uint8_t
+{
+    Purge,     // user-triggered unload, perform an extra purge before unload
+    Swap,      // part of an M600 sequence (no extra purge necessary)
+    Runout,    // triggered by runout (extra purge not possible)
+};
+
+void unload_filament(UnloadType unload=UnloadType::Purge);
+
 
 void lcd_printer_connected();
 void lcd_ping();

Firmware/variants/1_75mm_MK25-RAMBo10a-E3Dv6full.h

@@ -242,21 +242,26 @@
 #ifdef FILAMENTCHANGEENABLE
 #define FILAMENTCHANGE_XPOS 211
 #define FILAMENTCHANGE_YPOS 0
-#define FILAMENTCHANGE_ZADD 2
-#define FILAMENTCHANGE_FIRSTRETRACT -2
-#define FILAMENTCHANGE_FINALRETRACT -80
+#define FILAMENTCHANGE_ZADD Z_PAUSE_LIFT
 
-#define FILAMENTCHANGE_FIRSTFEED 70 //E distance in mm for fast filament loading sequence used used in filament change (M600)
-#define FILAMENTCHANGE_FINALFEED 25 //E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701) 
-#define FILAMENTCHANGE_RECFEED 5
+#define FILAMENTCHANGE_FIRSTRETRACT -2   // Retraction performed before parking the extruder or unloading filament
+#define FILAMENTCHANGE_FINALRETRACT -80  // Full filament retraction length
+
+#define FILAMENTCHANGE_FIRSTFEED 70 // E distance in mm for fast filament loading sequence used used in filament change (M600)
+#define FILAMENTCHANGE_FINALFEED 25 // E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701)
+
+#define FILAMENTCHANGE_PRIMEFEED   2 // E priming distance performed after resuming
+#define FILAMENTCHANGE_UNLOADFEED 10 // E priming distance performed before unloading
 
 #define FILAMENTCHANGE_XYFEED 50
+#define FILAMENTCHANGE_ZFEED 15
+
 #define FILAMENTCHANGE_EFEED_FIRST 20 // feedrate in mm/s for fast filament loading sequence used in filament change (M600)
 #define FILAMENTCHANGE_EFEED_FINAL 3.3f // feedrate in mm/s for slow filament loading sequence used in filament change (M600) and filament load (M701) 
-//#define FILAMENTCHANGE_RFEED 400
-#define FILAMENTCHANGE_RFEED 7000 / 60
-#define FILAMENTCHANGE_EXFEED 2
-#define FILAMENTCHANGE_ZFEED 15
+
+#define FILAMENTCHANGE_EFEED_RETRACT (7000 / 60) // quick filament retract feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_EJECT   (1000 / 60) // filament ejection feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_PRIME   ( 120 / 60) // filament priming feedrate (used before unloading and after resuming a print)
 
 #endif
 

Firmware/variants/1_75mm_MK25-RAMBo13a-E3Dv6full.h

@@ -243,21 +243,26 @@
 #ifdef FILAMENTCHANGEENABLE
 #define FILAMENTCHANGE_XPOS 211
 #define FILAMENTCHANGE_YPOS 0
-#define FILAMENTCHANGE_ZADD 2
-#define FILAMENTCHANGE_FIRSTRETRACT -2
-#define FILAMENTCHANGE_FINALRETRACT -80
+#define FILAMENTCHANGE_ZADD Z_PAUSE_LIFT
 
-#define FILAMENTCHANGE_FIRSTFEED 70 //E distance in mm for fast filament loading sequence used used in filament change (M600)
-#define FILAMENTCHANGE_FINALFEED 25 //E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701) 
-#define FILAMENTCHANGE_RECFEED 5
+#define FILAMENTCHANGE_FIRSTRETRACT -2   // Retraction performed before parking the extruder or unloading filament
+#define FILAMENTCHANGE_FINALRETRACT -80  // Full filament retraction length
+
+#define FILAMENTCHANGE_FIRSTFEED 70 // E distance in mm for fast filament loading sequence used used in filament change (M600)
+#define FILAMENTCHANGE_FINALFEED 25 // E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701)
+
+#define FILAMENTCHANGE_PRIMEFEED   2 // E priming distance performed after resuming
+#define FILAMENTCHANGE_UNLOADFEED 10 // E priming distance performed before unloading
 
 #define FILAMENTCHANGE_XYFEED 50
+#define FILAMENTCHANGE_ZFEED 15
+
 #define FILAMENTCHANGE_EFEED_FIRST 20 // feedrate in mm/s for fast filament loading sequence used in filament change (M600)
 #define FILAMENTCHANGE_EFEED_FINAL 3.3f // feedrate in mm/s for slow filament loading sequence used in filament change (M600) and filament load (M701) 
-//#define FILAMENTCHANGE_RFEED 400
-#define FILAMENTCHANGE_RFEED 7000 / 60
-#define FILAMENTCHANGE_EXFEED 2
-#define FILAMENTCHANGE_ZFEED 15
+
+#define FILAMENTCHANGE_EFEED_RETRACT (7000 / 60) // quick filament retract feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_EJECT   (1000 / 60) // filament ejection feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_PRIME   ( 120 / 60) // filament priming feedrate (used before unloading and after resuming a print)
 
 #endif
 

Firmware/variants/1_75mm_MK25S-RAMBo10a-E3Dv6full.h

@@ -242,21 +242,26 @@
 #ifdef FILAMENTCHANGEENABLE
 #define FILAMENTCHANGE_XPOS 211
 #define FILAMENTCHANGE_YPOS 0
-#define FILAMENTCHANGE_ZADD 2
-#define FILAMENTCHANGE_FIRSTRETRACT -2
-#define FILAMENTCHANGE_FINALRETRACT -80
+#define FILAMENTCHANGE_ZADD Z_PAUSE_LIFT
 
-#define FILAMENTCHANGE_FIRSTFEED 70 //E distance in mm for fast filament loading sequence used used in filament change (M600)
-#define FILAMENTCHANGE_FINALFEED 25 //E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701) 
-#define FILAMENTCHANGE_RECFEED 5
+#define FILAMENTCHANGE_FIRSTRETRACT -2   // Retraction performed before parking the extruder or unloading filament
+#define FILAMENTCHANGE_FINALRETRACT -80  // Full filament retraction length
+
+#define FILAMENTCHANGE_FIRSTFEED 70 // E distance in mm for fast filament loading sequence used used in filament change (M600)
+#define FILAMENTCHANGE_FINALFEED 25 // E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701)
+
+#define FILAMENTCHANGE_PRIMEFEED   2 // E priming distance performed after resuming
+#define FILAMENTCHANGE_UNLOADFEED 10 // E priming distance performed before unloading
 
 #define FILAMENTCHANGE_XYFEED 50
+#define FILAMENTCHANGE_ZFEED 15
+
 #define FILAMENTCHANGE_EFEED_FIRST 20 // feedrate in mm/s for fast filament loading sequence used in filament change (M600)
 #define FILAMENTCHANGE_EFEED_FINAL 3.3f // feedrate in mm/s for slow filament loading sequence used in filament change (M600) and filament load (M701) 
-//#define FILAMENTCHANGE_RFEED 400
-#define FILAMENTCHANGE_RFEED 7000 / 60
-#define FILAMENTCHANGE_EXFEED 2
-#define FILAMENTCHANGE_ZFEED 15
+
+#define FILAMENTCHANGE_EFEED_RETRACT (7000 / 60) // quick filament retract feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_EJECT   (1000 / 60) // filament ejection feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_PRIME   ( 120 / 60) // filament priming feedrate (used before unloading and after resuming a print)
 
 #endif
 

Firmware/variants/1_75mm_MK25S-RAMBo13a-E3Dv6full.h

@@ -243,21 +243,26 @@
 #ifdef FILAMENTCHANGEENABLE
 #define FILAMENTCHANGE_XPOS 211
 #define FILAMENTCHANGE_YPOS 0
-#define FILAMENTCHANGE_ZADD 2
-#define FILAMENTCHANGE_FIRSTRETRACT -2
-#define FILAMENTCHANGE_FINALRETRACT -80
+#define FILAMENTCHANGE_ZADD Z_PAUSE_LIFT
 
-#define FILAMENTCHANGE_FIRSTFEED 70 //E distance in mm for fast filament loading sequence used used in filament change (M600)
-#define FILAMENTCHANGE_FINALFEED 25 //E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701) 
-#define FILAMENTCHANGE_RECFEED 5
+#define FILAMENTCHANGE_FIRSTRETRACT -2   // Retraction performed before parking the extruder or unloading filament
+#define FILAMENTCHANGE_FINALRETRACT -80  // Full filament retraction length
+
+#define FILAMENTCHANGE_FIRSTFEED 70 // E distance in mm for fast filament loading sequence used used in filament change (M600)
+#define FILAMENTCHANGE_FINALFEED 25 // E distance in mm for slow filament loading sequence used used in filament change (M600) and filament load (M701)
+
+#define FILAMENTCHANGE_PRIMEFEED   2 // E priming distance performed after resuming
+#define FILAMENTCHANGE_UNLOADFEED 10 // E priming distance performed before unloading
 
 #define FILAMENTCHANGE_XYFEED 50
+#define FILAMENTCHANGE_ZFEED 15
+
 #define FILAMENTCHANGE_EFEED_FIRST 20 // feedrate in mm/s for fast filament loading sequence used in filament change (M600)
 #define FILAMENTCHANGE_EFEED_FINAL 3.3f // feedrate in mm/s for slow filament loading sequence used in filament change (M600) and filament load (M701) 
-//#define FILAMENTCHANGE_RFEED 400
-#define FILAMENTCHANGE_RFEED 7000 / 60
-#define FILAMENTCHANGE_EXFEED 2
-#define FILAMENTCHANGE_ZFEED 15
+
+#define FILAMENTCHANGE_EFEED_RETRACT (7000 / 60) // quick filament retract feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_EJECT   (1000 / 60) // filament ejection feedrate in mm/s
+#define FILAMENTCHANGE_EFEED_PRIME   ( 120 / 60) // filament priming feedrate (used before unloading and after resuming a print)
 
 #endif