post processor for FlatCAM NC files to make them work better for laser etching circuit boards.

gcode_post.py

# -*- coding: utf-8 -*-
from optparse import OptionParser
from os import path

"""
Quick and dirty script to edit FlatCAM NC files to make them work better for
laser etching circuit boards. 
"""

new_lines = []
move_up = "G00 Z"
move_down = "G01 Z-"


parser = OptionParser()
parser.add_option("-i", "--in-file", dest="inf", default=None,
                  help="Input GCode File", metavar="FILE")
parser.add_option("-o", "--out-prefix", dest="outf",
                  help="Output File prefix", default="post_")
parser.add_option("-v", "--verts", dest="verts",
                  help="Leave vert travel commands", action="store_true",
                  default=False)
parser.add_option("-c", "--cut-power", dest="pwr", default=255, type="int",
                  help="Power to turn the laser back on after moves")
parser.add_option("-s", "--travel-speed", dest="speed", default=200.0, type="float",
                  help="speed for X,Y movement")
                  
(opts, args) = parser.parse_args()
if opts.inf is None:
    print("need input Gcode file (-i)")
    exit()
    
with open(opts.inf) as f:
    raw = f.read().strip()
    lines = raw.split("\n")
for l in lines :
    if l.startswith("M03 S"):
        new_lines.append("M03 S1000") # max spindle speed
    elif l.startswith("F"): # Bad speed setting command, patch
        new_lines.append("G01 F%.1f" % opts.speed)
    # Check for move down first (denoted by - z value)
    elif l.startswith(move_down):
        if opts.verts:
            new_lines.append(l)
        new_lines.append("M4 S %d" % opts.pwr)
    elif l.startswith(move_up):
        new_lines.append("M5")
        if opts.verts:
            new_lines.append(l)
    else:
        new_lines.append(l)
# End of program, shut laser and return to home
new_lines.append("M5")
new_lines.append("G00 X0 Y0")
out = "\n".join(new_lines)
new_name = "%s%s" % (opts.outf, path.basename(opts.inf))
with open(new_name, "w") as of:
    of.write(out)
print("%d lines written" % len(new_lines))