New experimental parameter to adjust initial loading speed of the filament from the nozzle

xs/src/libslic3r/GCode/WipeTowerPrusaMM.cpp

@@ -793,7 +793,7 @@ void WipeTowerPrusaMM::toolchange_Unload(
     float turning_point = (!m_left_to_right ? xl : xr );
     float total_retraction_distance = m_cooling_tube_retraction + m_cooling_tube_length/2.f - 15.f; // the 15mm is reserved for the first part after ramming
     writer.suppress_preview()
-          .retract(15.f, 5000.f) // feedrate 5000mm/min = 83mm/s
+          .retract(15.f, m_filpar[m_current_tool].unloading_speed_start * 60.f) // feedrate 5000mm/min = 83mm/s
           .retract(0.70f * total_retraction_distance, 1.0f * m_filpar[m_current_tool].unloading_speed * 60.f)
           .retract(0.20f * total_retraction_distance, 0.5f * m_filpar[m_current_tool].unloading_speed * 60.f)
           .retract(0.10f * total_retraction_distance, 0.3f * m_filpar[m_current_tool].unloading_speed * 60.f)

xs/src/libslic3r/GCode/WipeTowerPrusaMM.hpp

@@ -66,8 +66,8 @@ public:
 
 	// Set the extruder properties.
 	void set_extruder(size_t idx, material_type material, int temp, int first_layer_temp, float loading_speed,
-                      float unloading_speed, float delay, int cooling_moves, float cooling_initial_speed,
+                      float unloading_speed, float unloading_speed_start, float delay, int cooling_moves,
-                      float cooling_final_speed, std::string ramming_parameters, float nozzle_diameter)
+                      float cooling_initial_speed, float cooling_final_speed, std::string ramming_parameters, float nozzle_diameter)
 	{
         //while (m_filpar.size() < idx+1)   // makes sure the required element is in the vector
         m_filpar.push_back(FilamentParameters());
@@ -77,6 +77,7 @@ public:
         m_filpar[idx].first_layer_temperature = first_layer_temp;
         m_filpar[idx].loading_speed = loading_speed;
         m_filpar[idx].unloading_speed = unloading_speed;
+        m_filpar[idx].unloading_speed_start = unloading_speed_start;
         m_filpar[idx].delay = delay;
         m_filpar[idx].cooling_moves = cooling_moves;
         m_filpar[idx].cooling_initial_speed = cooling_initial_speed;
@@ -217,6 +218,7 @@ private:
         int  			    first_layer_temperature = 0;
         float               loading_speed = 0.f;
         float               unloading_speed = 0.f;
+        float               unloading_speed_start = 0.f;
         float               delay = 0.f ;
         int                 cooling_moves = 0;
         float               cooling_initial_speed = 0.f;

xs/src/libslic3r/Print.cpp

@@ -201,6 +201,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
             || opt_key == "first_layer_temperature"
             || opt_key == "filament_loading_speed"
             || opt_key == "filament_unloading_speed"
+            || opt_key == "filament_unloading_speed_start"
             || opt_key == "filament_toolchange_delay"
             || opt_key == "filament_cooling_moves"
             || opt_key == "filament_minimal_purge_on_wipe_tower"
@@ -1124,6 +1125,7 @@ void Print::_make_wipe_tower()
             this->config.first_layer_temperature.get_at(i),
             this->config.filament_loading_speed.get_at(i),
             this->config.filament_unloading_speed.get_at(i),
+            this->config.filament_unloading_speed_start.get_at(i),
             this->config.filament_toolchange_delay.get_at(i),
             this->config.filament_cooling_moves.get_at(i),
             this->config.filament_cooling_initial_speed.get_at(i),

xs/src/libslic3r/PrintConfig.cpp

@@ -482,6 +482,14 @@ PrintConfigDef::PrintConfigDef()
     def->min = 0;
     def->default_value = new ConfigOptionFloats { 90. };
 
+    def = this->add("filament_unloading_speed_start", coFloats);
+    def->label = L("EXPERIMENTAL: Unloading speed at the start");
+    def->tooltip = L("Speed used for unloading the tip of the filament immediately after ramming. ");
+    def->sidetext = L("mm/s");
+    def->cli = "filament-unloading-speed-start=f@";
+    def->min = 0;
+    def->default_value = new ConfigOptionFloats { 83. };
+
     def = this->add("filament_toolchange_delay", coFloats);
     def->label = L("Delay after unloading");
     def->tooltip = L("Time to wait after the filament is unloaded. "

xs/src/libslic3r/PrintConfig.hpp

@@ -530,6 +530,7 @@ public:
     ConfigOptionFloats              filament_loading_speed;
     ConfigOptionFloats              filament_load_time;
     ConfigOptionFloats              filament_unloading_speed;
+    ConfigOptionFloats              filament_unloading_speed_start;
     ConfigOptionFloats              filament_toolchange_delay;
     ConfigOptionFloats              filament_unload_time;
     ConfigOptionInts                filament_cooling_moves;
@@ -596,6 +597,7 @@ protected:
         OPT_PTR(filament_loading_speed);
         OPT_PTR(filament_load_time);
         OPT_PTR(filament_unloading_speed);
+        OPT_PTR(filament_unloading_speed_start);
         OPT_PTR(filament_unload_time);
         OPT_PTR(filament_toolchange_delay);
         OPT_PTR(filament_cooling_moves);

xs/src/slic3r/GUI/Preset.cpp

@@ -314,8 +314,8 @@ const std::vector<std::string>& Preset::filament_options()
     static std::vector<std::string> s_opts {
         "filament_colour", "filament_diameter", "filament_type", "filament_soluble", "filament_notes", "filament_max_volumetric_speed",
         "extrusion_multiplier", "filament_density", "filament_cost", 
-        "filament_loading_speed", "filament_load_time", "filament_unloading_speed", "filament_unload_time", "filament_toolchange_delay",
+        "filament_loading_speed", "filament_load_time", "filament_unloading_speed", "filament_unloading_speed_start", "filament_unload_time",
-        "filament_cooling_moves", "filament_cooling_initial_speed", "filament_cooling_final_speed", "filament_ramming_parameters",
+        "filament_toolchange_delay", "filament_cooling_moves", "filament_cooling_initial_speed", "filament_cooling_final_speed", "filament_ramming_parameters",
         "filament_minimal_purge_on_wipe_tower", "temperature", "first_layer_temperature", "bed_temperature", "first_layer_bed_temperature",
         "fan_always_on", "cooling", "min_fan_speed", "max_fan_speed", "bridge_fan_speed", "disable_fan_first_layers", "fan_below_layer_time",
         "slowdown_below_layer_time", "min_print_speed", "start_filament_gcode", "end_filament_gcode","compatible_printers", "compatible_printers_condition",

xs/src/slic3r/GUI/Tab.cpp

@@ -1292,6 +1292,7 @@ void TabFilament::build()
         optgroup = page->new_optgroup(_(L("Toolchange parameters with single extruder MM printers")));
 		optgroup->append_single_option_line("filament_loading_speed");
         optgroup->append_single_option_line("filament_unloading_speed");
+        optgroup->append_single_option_line("filament_unloading_speed_start");
 		optgroup->append_single_option_line("filament_load_time");
 		optgroup->append_single_option_line("filament_unload_time");
         optgroup->append_single_option_line("filament_toolchange_delay");