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Filament Blockage Detection Optimization

Feature Description​

FAST version 1.3.8 optimizes the filament blockage detection feature, providing more precise blockage detection capabilities and flexible configuration options. This feature can monitor the extruder's material output in real-time and automatically pause printing and notify the user when blockage or filament runout is detected.

Important Notice

System Version Requirement: This feature requires FlyOS-Fast system version greater than or equal to v1.3.8 to function properly.

Configuration Method​

  • Add the following configuration to the printer.cfg file:
  • Please note this is a reference configuration, and specific parameters may need to be adjusted based on actual conditions
[filament_blockage_detection my_sensor]
switch_pin: ^PA10
extruder: extruder
distance_per_edge: 0.232
detection_length: 3
pause_on_runout: True
runout_gcode: M118 Filament blockage during printing
insert_gcode: M118 Filament restored during idle

Parameter Description:

ParameterDescription
switch_pinPin for the blockage detection sensor, ^ enables the pull-up resistor
extruderThe associated extruder name
distance_per_edgeThe filament travel distance (in millimeters) corresponding to each sensor trigger. This parameter is automatically calculated and updated after executing the calibration command; no need to set an initial value manually
detection_lengthDetection length threshold (in millimeters), if the sensor is not triggered within this distance, blockage is detected
pause_on_runoutWhether to automatically pause printing when blockage is detected
runout_gcodeG-code command executed when blockage is detected
insert_gcodeG-code command executed when filament reinsertion is detected
Automatic Calibration Notice

The distance_per_edge parameter is automatically optimized after executing the CALIBRATE_FILAMENT_BLOCKAGE calibration command and is permanently saved to the configuration file via the SAVE_CONFIG command. During initial configuration, any value can be entered; it will be automatically overwritten after calibration.

Calibration Procedure​

To ensure detection accuracy, it is recommended to calibrate the sensor before use.

Step 1: Heat the Nozzle​

Heat the nozzle to the normal working temperature (recommended 220°C):

M104 S220
M109 S220

Step 2: Execute the Calibration Command​

Once the nozzle reaches the target temperature, execute the following calibration command:

CALIBRATE_FILAMENT_BLOCKAGE SENSOR=my_sensor TEMPERATURE=220

Command Description:

  • SENSOR: Sensor name, corresponding to [filament_blockage_detection my_sensor] in the configuration
  • TEMPERATURE: Nozzle temperature during calibration

Step 3: Save Calibration Results​

After calibration is completed, the system automatically calculates the optimal distance_per_edge parameter. To save manually, execute:

SAVE_CONFIG

Important Reminders​

Firmware Update Requirement

After upgrading to FAST 1.3.8, the lower-level machine firmware must be updated, otherwise the filament blockage detection feature may not work properly.

Please refer to the Screen Firmware Update documentation to complete the firmware upgrade.

Troubleshooting​

Issue 1: Filament Blockage Detection Not Triggering​

Possible Causes:

  • The sensor is not properly connected
  • Incorrect switch_pin configuration
  • Lower-level machine firmware not updated

Solutions:

  1. Check the sensor hardware connection
  2. Verify the pin configuration matches the actual hardware
  3. Update the lower-level machine firmware to the latest version

Issue 2: False Blockage Alarms​

Possible Causes:

  • Inaccurate distance_per_edge parameter
  • The detection_length threshold is set too small

Solutions:

  1. Re-execute the calibration command
  2. Appropriately increase the detection_length value (recommended 3-5mm)

Issue 3: Calibration Failure​

Possible Causes:

  • Nozzle temperature does not meet the requirement
  • Sensor hardware malfunction

Solutions:

  1. Confirm the nozzle has been heated to the specified temperature
  2. Check whether the sensor is functioning properly
  3. Try restarting the Klipper service

Usage Recommendations​

  • It is recommended to recalibrate the sensor whenever changing filament brand or diameter
  • Regularly check the sensor status to ensure detection accuracy
  • If the filament blockage detection feature has not been used for an extended period, it is recommended to recalibrate before use
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