Mecode

GCode for all

Mecode is designed to simplify GCode generation. It is not a slicer, thus it can not convert CAD models to 3D printer ready code. It simply provides a convenient, human-readable layer just above GCode. If you often find yourself manually writing your own GCode, then mecode is for you.

Basic Use

To use, simply instantiate the G object and use its methods to trace your desired tool path.

from mecode import G
g = G()
g.move(10, 10)  # move 10mm in x and 10mm in y
g.arc(x=10, y=5, radius=20, direction='CCW')  # counterclockwise arc with a radius of 20
g.meander(5, 10, spacing=1)  # trace a rectangle meander with 1mm spacing between passes
g.abs_move(x=1, y=1)  # move the tool head to position (1, 1)
g.home()  # move the tool head to the origin (0, 0)

By default mecode simply prints the generated GCode to stdout. If instead you want to generate a file, you can pass a filename when instantiating the G object.

g = G(outfile='path/to/file.gcode')

NOTE: When using the option direct_write=True or when writing to a file, g.teardown() must be called after all commands are executed. If you are writing to a file, this can be accomplished automatically by using G as a context manager like so:

with G(outfile='file.gcode') as g:
    g.move(10)

When the with block is exited, g.teardown() will be automatically called.

The resulting toolpath can be visualized in 3D using the mayavi or matplotlib package with the view() method:

g = G()
g.meander(10, 10, 1)
g.view()

The graphics backend can be specified when calling the view() method, e.g. g.view('mayavi').

Direct control via serial communication

With the option direct_write=True, a serial connection to the controlled device is established via USB serial at a virtual COM port of the computer and the g-code commands are sent directly to the connected device using a serial communication protocol:

import mecode
g = mecode.G(
    direct_write=True, 
    direct_write_mode="serial", 
    printer_port="/dev/tty.usbmodem1411", 
    baudrate=115200
)  # Under MS Windows, use printer_port="COMx" where x has to be replaced by the port number of the virtual COM port the device is connected to according to the device manager.
g.write("M302 S0")  # send g-Code. Here: allow cold extrusion. Danger: Make sure extruder is clean without filament inserted 
g.absolute()  # Absolute positioning mode
g.move(x=10, y=10, z=10, F=500)  # move 10mm in x and 10mm in y and 10mm in z at a feedrate of 500 mm/min
g.retract(10)  # Move extruder motor
g.write("M400")  # IMPORTANT! wait until execution of all commands is finished
g.teardown()  # Disconnect (close serial connection)

All GCode Methods

All methods have detailed docstrings and examples.

set_home()
reset_home()
feed()
dwell()
home()
move()
abs_move()
arc()
abs_arc()
rect()
meander()
clip()
triangular_wave()

Matrix Transforms

A wrapper class, GMatrix will run all move and arc commands through a 2D transformation matrix before forwarding them to G.

To use, simply instantiate a GMatrix object instead of a G object:

g = GMatrix()
g.push_matrix()      # save the current transformation matrix on the stack.
g.rotate(math.pi/2)  # rotate our transformation matrix by 90 degrees.
g.move(0, 1)         # same as moves (1,0) before the rotate.
g.pop_matrix()       # revert to the prior transformation matrix.

The transformation matrix is 2D instead of 3D to simplify arc support.

Renaming Axes

When working with a machine that has more than one Z-Axis, it is useful to use the rename_axis() function. Using this function your code can always refer to the vertical axis as 'Z', but you can dynamically rename it.

Installation

The easiest method to install mecode is with pip:

sudo pip install mecode

To install from source:

$ git clone https://github.com/jminardi/mecode.git
$ cd mecode
$ pip install -r requirements.txt
$ python setup.py install

Optional Dependencies

The following dependencies are optional, and are only needed for visualization. An easy way to install them is to use Canopy or conda.

numpy
mayavi
matplotlib

TODO

add pressure box comport to __init__() method
build out multi-nozzle support
- include multi-nozzle support in view method.
factor out aerotech specific methods into their own class

Credits

This software was developed by the Lewis Lab at Harvard University.