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Armored Turtle Automated Filament Control (AFC) Buffer Ram Sensor

This file describes using a filament buffer as a ram sensor. This is part of the Armored Turtle Automated Filament Control (AFC) project.

Overview

Ram sensor is compatible with two types of buffers: TurtleNeck, TurtleNeck 2.0.

The filament loading and unloading process can use the two sensor design of these buffers in order to evaluate the position of the filament.

Basic Functionality

During TOOL_LOAD filament will travel to buffer sensor and then execute the afc_bowden_length to the tool head

  • If the buffer is expanded after the afc_bowden_length is complete then it will move forward with the tool load.
  • If the buffer is not expanded after the afc_bowden_length then AFC will perform short moves until the buffer expands and the tool load will continue.
  • After the tool_stn is complete the AFC will then pull back off the advance sensor, checking that it was loaded successfully and resetting the buffer.

During TOOL_UNLOAD AFC will perform the user specified macros (cut/tip shaping etc.).

  • Once these macros are finished AFC will pull back to the trailing sensor to ensure consistent position of the buffer.
  • The rest of the unload will follow.

Verifying lane loaded to toolhead

During PREP if homing is enabled AFC can verify that filament is loaded to toolhead by advancing filament until the advance sensor is triggered. If the advance sensor does not trigger after a 200mm move, then AFC will give the following error: 

Buffer toolhead loaded check failed for lane3. Please verify that lane3 is loaded to toolhead.
If lane is not loaded to toolhead then run AFC_RESET and choose lane3 to reset back to hub.
Once lane is reset run UNSET_LANE_LOADED macro.
To enable this feature add enable_buffer_tool_check: True to your AFC_Boxturtle/AFC_vivid etc. config section.

Configuration

Required Configuration

Under [AFC_extruder extruder] section:

pin_tool_start: buffer

  • By setting the pin_tool_start to buffer the ram sensor will be enabled.

Under [AFC_Buffer Turtle_1]

Note

advance_pin and trailing_pin must be defined

  • advance_pin: Pin for the advance sensor.
  • trailing_pin: Pin for the trailing sensor.

Under [AFC_extruder <extruder_name>], [AFC_<unit_name> <name>] or [AFC_stepper lane(n)]; the buffer name must be defined. This allows having a buffer per extruder, unit or lane. Defining buffer in AFC_stepper config overrides buffer variable being set in other places, and defining buffer in AFC_<unit_name> overrides buffer being set in AFC_extruder.

Examples:

[AFC_extruder <extruder_name>]
buffer: Turtle_1
pin_tool_start: buffer
<rest_of_config>

[AFC_BoxTurtle <unit_name>]
buffer: Turtle_1
<rest_of_config>

[AFC_stepper <stepper_name>]
buffer: Turtle_1
<rest_of_config>

Optional Configuration

Under [AFC] section in the AFC.cfg file:

tool_max_load_checks: 4 can be set for the amount of times the AFC pulls back after load to come off the advance sensor. See here for more information.

  • Default 4

tool_max_unload_attempts: 2 can be set for the amount of repetitions AFC pulls back to trailing sensor on unload. See here for more information.

  • Default 2

Tuning

The following parameters should be tuned for the specific setup. These can be found in the [AFC_hub <unit_name>] section. - afc_bowden_length should be set so that on unload the filament comes just short of the hub sensor. - tool_unload_stn should be set so that on unload the filament clears the extruder.