pyGCodeDecode

What is this repository for?

This package reads the target trajectory and commands for changing firmware settings from a GCode file. Furthermore it simulates a motion planner with acceleration and jerk / junction control. The simulation result describes the nozzle and extrusion axis position and velocity at every point in time. Notably, this method does try to simulate the real printer movements at a higher accuracy than assuming constant velocity. This is achieved by replicating grbl and derivative firmwares specific movement planner solutions, such as Junction Deviation as an interpretation for Jerk. This python package can be used to generate time dependent boundary conditions from a GCode file, needed in additive manufacturing simulations such as Fused Filament Fabrication. With implemented 3D plotting functions, it also can be useful as a GCode analyzer tool, to visualize local velocities to gain better process understanding.

The package is highly modularized to enable quick modification and extension of all features.

PyGCodeDecode is currently as a generator for Abaqus Event Series to model the material extrusion process.

Install pyGCodeDecode

It is recommended that you first create a virtual Python-environment, e.g. using the venv-module built into Python. You can clone the repository and run

    pip install .

from inside the root directory. Alternatively you can simply install from PyPI:

    pip install pyGCodeDecode

If you plan to contribute to the development, install in development mode and with the additional dependencies:

    pip install -e .[DEVELOPER]

You may want to verify the installation and version. Inside your environment, just run:

    python -c "import pyGCodeDecode
    print(pyGCodeDecode.__version__)"

This should return the correct version.

Supported GCode commands

fully supported:

    "G0": {"E": None, "X": None, "Y": None, "Z": None, "F": None},  # non Extrusion Move
    "G1": {"E": None, "X": None, "Y": None, "Z": None, "F": None},  # Extrusion Move
    "G4": {"P": None, "S": None},  # Dwell
    "M82": None,  # E Absolute
    "M83": None,  # E Relative
    "G20": None,  # Inches
    "G21": None,  # Milimeters
    "G90": None,  # Absolute Positioning
    "G91": None,  # Relative Positioning
    "G92": {"E": None, "X": None, "Y": None, "Z": None},  # Set Position
    ";": None,  # Comment

partially supported:

    "M203": {"E": None, "X": None, "Y": None, "Z": None},  # Max Feedrate *read only
    "M204": {"P": None, "R": None, "S": None, "T": None},  # Starting Acceleration *P only
    "M205": {"E": None, "J": None, "S": None, "X": None, "Y": None, "Z": None},  # Advanced Settings *X only
    "G10": {"S": None}, *read only
    "G11": None, *read only

Workflow

define a printer with default parameters in a .yaml

example definition (also see ./pyGCodeDecode/data/default_printer_presets.yaml):

    prusa_mini:
            # general properties
            nozzle_diam: 0.4
            filament_diam: 1.75
            # default settings
            p_vel: 35
            p_acc: 1250
            jerk: 8
            # axis max speeds
            vX: 180
            vY: 180
            vZ: 12
            vE: 80
            firmware: marlin_jerk

create a script to run pyGCD

Create a .py file to set up and run the simulation. Import the package:

    from pyGCodeDecode import gcode_interpreter

load the setup with:

    setup = gcode_interpreter.setup(filename=r"e./pygcodedecode/data/default_printer_presets.yaml")

select a printer:

    setup.select_printer("prusa_mini")

(optional) set custom properties:

    setup.set_property({"layer_cue": "LAYER_CHANGE"})

run the simulation:

    simulation = gcode_interpreter.simulation(filename=r"example\example.gcode", initial_machine_setup=setup)

use the simulation obj from now on, to retrieve information or use plot functions:

get axis values at a certain time (e.g. 2.6 s):

    simulation.get_values(t=2.6)

plot in 3D:

    simulation.plot_3d()

pyGCD can also be used to create files defining an event series for ABAQUS simulations:

    generate_abaqus_event_series(
            simulation=simulation,
            filpath="path/to/event_series.csv"
    )

For more in depth information have a look into the documentation.