Add mixing extruder support

config/printer-geeetech-301.cfg

@@ -0,0 +1,158 @@
+# This file contains common pin mappings for the GTM32 PRO board in the Geeetech 301 printer
+# To use this config, the firmware should be compiled for the
+# STM32F103 with "No bootloader" and with "Use USB for communication"
+# disabled.
+
+# The "make flash" command does not work on the GTM32 PRO. Instead,
+# after running "make", run the following command to flash the board:
+#  stm32flash -w out/klipper.bin -v -i rts,-dtr,dtr /dev/ttyUSB0
+
+# See docs/Config_Reference.md for a description of parameters.
+
+[board_pins gtm32_pro_vb]
+aliases_probes: X_MIN=PE5,X_MAX=PE4,Y_MIN=PE3,Y_MAX=PE2,Z_MIN=PE1,Z_MAX=PE0
+aliases_temp: E0_TEMP=PC0,T0_PWM=PB4,E1_TEMP=PC1,T1_PWM=PB5,E2_TEMP=PC2,T2_PWM=PB0,BED_TEMP=PC3,BED_PWM=PB1
+aliases_other: FAN0_PWM=PB7,FAN1_PWM=PB8,FAN2_PWM=PB9,BEEP=PB10,LED_PWM=PD12
+aliases_motors: X_EN=PA8,X_DIR=PD13,X_STEP=PC6,Y_EN=PA15,Y_DIR=PA11,Y_STEP=PA12,Z_EN=PB3,Z_DIR=PD3,Z_STEP=PD6,E0_EN=PC15,E0_DIR=PC13,E0_STEP=PC14,E1_EN=PA1,E1_DIR=PB6,E1_STEP=PA0,E2_EN=PC4,E2_DIR=PB11,E2_STEP=PB2
+aliases_lcd: LCD_ENC1=PE9,LCD_ENC2=PE8,LCD_PUSH=PE13,LCD_BEEP=PE12,LCD_RS=PE6,LCD_E=PE14,LCD_D4=PD8,LCD_D5=PD9,LCD_D6=PD10,LCD_D7=PE15
+
+[multi_pin heater]
+pins: T0_PWM,T1_PWM,T2_PWM
+
+[multi_pin printhead_fans]
+pins: FAN1_PWM,FAN2_PWM
+
+[thermistor bed_thermistor]
+temperature1: 24
+resistance1: 104600
+temperature2: 40
+resistance2: 47700
+temperature3: 67
+resistance3: 13000
+
+[stepper_a]
+step_pin: X_STEP
+dir_pin: !X_DIR
+enable_pin: !X_EN
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^X_MAX
+homing_speed: 50
+position_endstop: 216
+arm_length: 201
+
+[stepper_b]
+step_pin: Y_STEP
+dir_pin: !Y_DIR
+enable_pin: !Y_EN
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^Y_MAX
+
+[stepper_c]
+step_pin: Z_STEP
+dir_pin: !Z_DIR
+enable_pin: !Z_EN
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^Z_MAX
+
+[extruder]
+step_pin: E0_STEP
+dir_pin: !E0_DIR
+enable_pin: !E0_EN
+microsteps: 16
+rotation_distance: 32
+nozzle_diameter: 0.4
+filament_diameter: 1.75
+heater_pin: multi_pin:heater
+sensor_type: EPCOS 100K B57560G104F
+sensor_pin: E2_TEMP
+min_extrude_temp: 160
+min_temp: 0
+max_temp: 250
+
+[extruder1]
+step_pin: E1_STEP
+dir_pin: !E1_DIR
+enable_pin: !E1_EN
+microsteps: 16
+rotation_distance: 32
+nozzle_diameter: 0.4
+filament_diameter: 1.75
+shared_heater: extruder
+
+[extruder2]
+step_pin: E2_STEP
+dir_pin: !E2_DIR
+enable_pin: !E2_EN
+microsteps: 16
+rotation_distance: 32
+nozzle_diameter: 0.4
+filament_diameter: 1.75
+shared_heater: extruder
+
+[heater_bed]
+heater_pin: BED_PWM
+sensor_type: bed_thermistor
+sensor_pin: BED_TEMP
+min_temp: 0
+max_temp: 150
+
+[temperature_sensor board]
+sensor_type: temperature_mcu
+gcode_id: MCU
+
+[temperature_sensor secondary]
+sensor_pin: E1_TEMP
+sensor_type: EPCOS 100K B57560G104F
+gcode_id: SEC
+
+[temperature_sensor ambient]
+sensor_pin: E0_TEMP
+sensor_type: EPCOS 100K B57560G104F
+gcode_id: AMB
+
+[homing_heaters]
+heaters: extruder
+
+[fan]
+pin: FAN0_PWM
+
+[heater_fan printhead]
+pin: multi_pin:printhead_fans
+heater: extruder
+max_power: 0.6
+off_below: 0.2
+shutdown_speed: 0
+
+[mixingextruder]
+extruders: extruder,extruder1,extruder2
+
+[mcu]
+serial: /dev/serial/by-id/usb-FTDI_FT232R_USB_UART_AH06IBBC-if00-port0
+restart_method: cheetah
+
+[printer]
+kinematics: delta
+max_velocity: 300
+max_accel: 3000
+max_z_velocity: 150
+delta_radius: 94
+
+[output_pin beep]
+pin: BEEP
+
+[output_pin lcd_beep]
+pin: LCD_BEEP
+
+[display]
+lcd_type: hd44780
+rs_pin: LCD_RS
+e_pin: LCD_E
+d4_pin: LCD_D4
+d5_pin: LCD_D5
+d6_pin: LCD_D6
+d7_pin: LCD_D7
+encoder_pins: ^LCD_ENC1,^LCD_ENC2
+click_pin: ^LCD_PUSH

config/sample-mixing-extruder.cfg

@@ -0,0 +1,60 @@
+# This file contains a configuration snippet for a printer using a
+# mixing extruder (3 in - 1 out). The 3 extruder motors should be defined
+# as extruder, extruder1 and extruder2
+
+# See docs/Config_Reference.md for a description of parameters.
+
+[mixingextruder]
+extruders: extruder,extruder1,extruder2
+
+[gcode_macro M163]
+gcode:
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR={S} SCALE={P}
+
+[gcode_macro M164]
+default_parameter_S: ACTIVE
+gcode:
+    SAVE_MIXING_EXTRUDERS EXTRUDER=mixingextruder MIXING_EXTRUDER={S}
+
+[gcode_macro M165]
+default_parameter_A: 0.
+default_parameter_B: 0.
+default_parameter_C: 0.
+gcode:
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR=0 SCALE={A}
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR=1 SCALE={B}
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR=2 SCALE={C}
+    SAVE_MIXING_EXTRUDERS EXTRUDER=mixingextruder MIXING_EXTRUDER=ACTIVE
+
+[gcode_macro M166]
+default_parameter_T: ACTIVE
+default_parameter_S: RESET
+default_parameter_A: -1
+default_parameter_Z: -1
+default_parameter_I: -1
+default_parameter_J: -1
+gcode:
+    # Assume there is only one mixing extruder and it is named "mixingextruder"
+    {% set extruder = 'mixingextruder' %}
+    {% if extruder >= 0 %}
+      {% if params.A|float >= 0 and params.Z|float >= 0 and params.I|int >= 0 and params.J|int >= 0 %}
+        ADD_MIXING_GRADIENT EXTRUDER={extruder} START_HEIGHT={A} END_HEIGHT={Z} START={I} END={J}
+        SET_MIXING_GRADIENT EXTRUDER={extruder} ENABLE={S}
+      {% elif S != "RESET" %}
+        SET_MIXING_GRADIENT EXTRUDER={extruder} ENABLE={S}
+      {% else %}
+        RESET_MIXING_GRADIENT EXTRUDER={extruder}
+      {% endif %}
+    {% else %}
+      {action_raise_error("Could not find mixingextruder")}
+    {% endif %}
+
+[gcode_macro M567]
+default_parameter_P: ACTIVE
+default_parameter_E: 1:0:0
+gcode:
+    {% set weights = (E+":0:0").split(":") %}
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR=0 SCALE={weights[0]}
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR=1 SCALE={weights[1]}
+    SET_MIXING_EXTRUDER EXTRUDER=mixingextruder MIXING_MOTOR=2 SCALE={weights[2]}
+    SAVE_MIXING_EXTRUDERS EXTRUDER=mixingextruder MIXING_EXTRUDER={P}

docs/Config_Reference.md

@@ -1825,6 +1825,25 @@ more information.
 #   parameters.
 ```
 
+### [mixingextruder]
+
+A mixing printhead which has <n>in-1out mixing nozzle. When specified
+16 virtual mixingextruders are created ("mixingextruder",
+"mixingextruder1", ... "mixingextruder15"). They can be activated like
+the standard extruders with "ACTIVATE_EXTRUDER EXTRUDER=mixingextruder" and
+"MIXING_STATUS EXTRUDER=mixingextruder" provides some statistics.
+When activated additional g-code are available. See
+[G-Codes](G-Codes.md#mixing-commands) for
+a detailed description of the additional commands.
+
+```
+[mixingextruder]
+#extruders:
+#   Which extruders feed into the hotend/nozzle. provide a comma
+#   separated list, eg. "extruder,extruder1,extruder2".
+#   This configuration is required.
+```
+
 ### [manual_stepper]
 
 Manual steppers (one may define any number of sections with a

docs/G-Codes.md

@@ -325,6 +325,44 @@ enabled:
   future G-Code movement commands may run in parallel with the stepper
   movement.
 
+### Mixingextruder Commands
+
+The following commands are available when a
+[mixingextruder config section](Config_Reference.md#mixingextruder) is
+enabled:
+- `ACTIVATE_EXTRUDER EXTRUDER=<mixingextruder>`: This command activates
+  the specified mixing extruder. Subsequent G1 commands use the mixing
+  defined for that mixing extruder.
+- `SET_MIXING_EXTRUDER MIXING_MOTOR=<extruder>
+  SCALE=<scale>`: Set a scale for a given extruder.
+- `SAVE_MIXING_EXTRUDERS [MIXING_EXTRUDER=<target>]`: Saves the previous set scales to a given
+  target mixing extruder. If the target is is not given, save it at the
+  currently active mixing extruder. For example with a 2in-iout extruder to set
+  the mix for "mixingextruder3" to 75%/25% one would use:
+  `SET_MIXING_EXTRUDER MIXING_MOTOR=0 SCALE=75`
+  `SET_MIXING_EXTRUDER MIXING_MOTOR=1 SCALE=25`
+  `SAVE_MIXING_EXTRUDERS MIXING_EXTRUDER=3`
+- `ADD_MIXING_GRADIENT EXTRUDER=<mixingextruder> START=<start_source>
+  END=<end_source> START_HEIGHT=<start> END_HEIGHT=<end>`: Configures
+  (adds) a gradient for the given mixing extruder. The sources are
+  references to (other) mixing extruders. For example if with a 2in-1out
+  extruder "mixingextruder2" is set mix 100%/0% and "mixingextruder3"
+  is set to 0%/100%
+  `ADD_MIXING_GRADIENT EXTRUDER=mixingextruder START=2 END=3
+  START_HEIGHT=10 END_HEIGHT=20`
+  `ADD_MIXING_GRADIENT EXTRUDER=mixingextruder START=3 END=2
+  START_HEIGHT=20 END_HEIGHT=30`
+  would setup a gradient for "mixingextruder" which is constant 100%/0%
+  between heights 0mm and 10mm, then linearly interpolates to 0%/100% at
+  height 20mm and back to 100%/0% at height 30mm and stays that for all
+  heights above.
+- `RESET_MIXING_GRADIENT EXTRUDER=<mixingextruder>`: Reset/remove all
+  gradients for the given mixing extruder.
+- `SET_MIXING_GRADIENT EXTRUDER=<mixingextruder> [ENABLE=<enable>] [METHOD=<method>]`:
+  Enable/disable the gradient at the given mixing extruder and set the gradient method.
+- `MIXING_STATUS EXTRUDER=<mixingextruder>`: Returns the configuration
+  and status of the given mixing extruder.
+
 ### Extruder stepper Commands
 
 The following command is available when an

docs/Mixing_Extruder.md

@@ -0,0 +1,95 @@
+# Mixing extruder
+
+This document describes how to configure and use a filament mixing extruder.
+Please also refer to the [config reference](Config_Reference.md) and supported
+[G-Codes](G-Codes.md).
+
+## Configuring a mixing extruder.
+
+A mixing extruder has N-filament inputs and a single nozzle. This requires
+N independent filament drives. They have to be defined in the config as regular
+extruders.
+
+Since they all drive filament to the same hotend they must have the
+`shared_heater` property set to point to one of them. For this reason all
+heater-related parameters should be set only for that one.
+
+Following individual filament drivers definitions there should be the
+`[mixingextruder]` section which groups all of them to tell Klipper that
+they in fact drive the same mixing hotend.
+
+Here is an example of configuration snippet for 3-to-1 mixing extruder:
+```
+# "Alpha" stepper
+[extruder]
+step_pin: PC7
+dir_pin: !PC8
+enable_pin: !PA18
+microsteps: 16
+rotation_distance: 7.15
+nozzle_diameter: 0.400
+filament_diameter: 1.75
+heater_pin: PC22
+sensor_type: EPCOS 100K B57560G104F
+sensor_pin: PA6
+control: pid
+pid_kp: 37.919
+pid_ki: 0.950
+pid_kd: 378.241
+min_temp: 0
+max_temp: 275
+pressure_advance: 0.1
+min_extrude_temp: 0
+
+# "Beta" stepper
+[extruder1]
+step_pin: PB3
+dir_pin: !PC10
+enable_pin: !PB4
+microsteps: 16
+rotation_distance: 7.15
+nozzle_diameter: 0.400
+filament_diameter: 1.75
+pressure_advance: 0.1
+shared_heater: extruder
+
+# "Gamma" stepper
+[extruder2]
+step_pin: PB1
+dir_pin: !PB0
+enable_pin: !PB2
+microsteps: 16
+rotation_distance: 7.15
+nozzle_diameter: 0.400
+filament_diameter: 1.75
+pressure_advance: 0.1
+shared_heater: extruder
+
+[mixingextruder]
+extruders: extruder,extruder1,extruder2
+```
+
+Stepper parameters may vary among all the drivers but in most systems they are
+identical.
+
+## Retractions
+
+For correct operation of a mixing extruder all N input filaments should be
+retracted by the same amount regardless of the mixing ratio used. Most
+3D printer firmware implement that via firmware retractions.
+
+The current implementation of retractions in Klipper is different and is based
+on automatic tracking of extrusion moves. When Klipper detects a retraction
+(which is backward extrusion move) it sets internally the mixing ratio for
+each filament driver to 1/N ensuring that all filaments are moved by the same
+distance. The retracted distance is accumulated and used to detect the end
+of subsequent unretraction move. When that happens the mixing ratio is restored.
+
+Because retractions happen with mixing ratio of 1/N for each stepper the amount
+the filament actually moves and the move speed is also divided by N. This
+currently has to be accounted for in a slicer firmware. For example whe one
+wants to retract by 3mm with the speed of 50mm/s a 3-to-1 mixing extruder then
+the values in the slicer need to be 3 * 3mm = 9mm and 3 * 50mm/s = 150mm/s.
+
+A mixing extruder should be thought of as if it was driving a "virtual filament"
+at the point where it enters the nozzle.

docs/Overview.md

@@ -41,6 +41,7 @@ communication with the Klipper developers.
     using adxl345 accelerometer hardware to measure resonance.
 - [Pressure advance](Pressure_Advance.md): Calibrate extruder
   pressure.
+- [Mixing extruder](Mixing_Extruder.md): Information about setting-up and using filament mixing extruders.
 - [Slicers](Slicers.md): Configure "slicer" software for Klipper.
 - [Command Templates](Command_Templates.md): G-Code macros and
   conditional evaluation.