grbl_81 unable to write gcode output file

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falviani
Posts: 253
Joined: Tue May 07, 2019 8:49 pm

grbl_81 unable to write gcode output file

Post by falviani »

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.17337 (Git)
Hello all,

Here is my setup:
Build type: Release
Branch: master
Hash: 0871fb49c71f1ac4029e441814332368f42bd78a
Python version: 3.6.8
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/United States (en_US)

Nightly: FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015.7z

When I ran the post process operation on a simple test (post processor is grbl_81), I saw this in the report view:
Running the Python command 'Path_Post' failed:
Traceback (most recent call last):
File "E:\Downloads\3D Printer software installers etc\FreeCAD\FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015\FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015\Mod\Path\PathScripts\PathPost.py", line 390, in Activated
(fail, rc) = self.exportObjectsWith(finalpostlist, job)
File "E:\Downloads\3D Printer software installers etc\FreeCAD\FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015\FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015\Mod\Path\PathScripts\PathPost.py", line 212, in exportObjectsWith
gcode = processor.export(objs, filename, postArgs)
File "E:\Downloads\3D Printer software installers etc\FreeCAD\FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015\FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015\Mod\Path\PathScripts\PathPostProcessor.py", line 102, in export
return self.script.export(obj, filename, args)
File "E:/Downloads/3D Printer software installers etc/FreeCAD/FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015/FreeCAD_0.19.17337_x64_LP_12.1.2_PY3QT5-WinVS2015/Mod/Path/PathScripts//post\grbl_G81_post.py", line 237, in export
gfile = pythonopen(filename,"w")

name 'pythonopen' is not defined

Using the normal grbl post processor worked fine. This looks like a bug in the grbl_81 code.
actuate
Posts: 25
Joined: Mon Sep 23, 2019 8:47 pm

Re: grbl_81 unable to write gcode output file

Post by actuate »

I'm not sure (only been using FreeCAD a few days) if this file has been dropped in the latest release as it is not present in the git src tree...

However I had a tinker. Basically I've ripped a few lines from grbl_post.py, a) to fix the "pythonopen" issue, b) updated drilling feedrate, however there will probably be more???

Code: Select all

# -*- coding: utf-8 -*-
#***************************************************************************
#*   (c) Gauthier Briere - 2018                                            *
#*                                                                         *
#*   This program is free software; you can redistribute it and/or modify  *
#*   it under the terms of the GNU Lesser General Public License (LGPL)    *
#*   as published by the Free Software Foundation; either version 2.1 of   *
#*   the License, or (at your option) any later version.                   *
#*   for detail see the LICENSE text file.                                 *
#*                                                                         *
#*   This program is distributed in the hope that it will be useful,       *
#*   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
#*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
#*   GNU Lesser General Public License for more details.                   *
#*                                                                         *
#*   You should have received a copy of the GNU Library General Public     *
#*   License along with This program; if not, write to the Free Software   *
#*   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
#*   USA                                                                   *
#*                                                                         *
#***************************************************************************/


TOOLTIP='''
Generate g-code from a Path that is compatible with the grbl controller.
import grbl_post
grbl_post.export(object, "/path/to/file.ncc")
'''


import FreeCAD
from FreeCAD import Units
import PathScripts.PostUtils as PostUtils
import argparse
import datetime
import shlex


#*********************************************************************************************************
# Globals set customization preferences
#*********************************************************************************************************

# Default values for command line arguments:
OUTPUT_COMMENTS =        True     # default output of comments in output gCode file
OUTPUT_HEADER =          True     # default output header in output gCode file
OUTPUT_LINE_NUMBERS =    False    # default doesn't output line numbers in output gCode file
SHOW_EDITOR =            True     # default show the resulting file dialog output in GUI
PRECISION =              3        # Default precision for metric (see http://linuxcnc.org/docs/2.7/html/gcode/overview.html#_g_code_best_practices)
TRANSLATE_DRILL_CYCLES = True     # If true, G81, G82 & G83 are translated in G0/G1 moves
PREAMBLE = '''G17 G90
'''                               # default preamble text will appear at the beginning of the gCode output file.
POSTAMBLE = '''M5
G17 G90
M2
'''                               # default postamble text will appear following the last operation.

# Customisation with no command line argument
MODAL =                  False    # if true commands are suppressed if the same as previous line.
LINENR =                   100    # line number starting value
LINEINCR =                  10    # line number increment
OUTPUT_TOOL_CHANGE =     False    # default don't output M6 tool changes (comment it) as grbl currently does not handle it
DRILL_RETRACT_MODE =     'G98'    # Default value of drill retractations (CURRENT_Z) other possible value is G99
MOTION_MODE =            'G90'    # G90 for absolute moves, G91 for relative
UNITS =                  'G21'    # G21 for metric, G20 for us standard
#UNIT_FORMAT = 'mm'
UNIT_SPEED_FORMAT = 'mm/min'
SPEED_MULTIPLIER =          60    # *60 convert FreeCAD's mm/s to mm/mn
PRE_OPERATION =         ''''''    #Pre operation text will be inserted before every operation
POST_OPERATION =        ''''''    #Post operation text will be inserted after every operation
TOOL_CHANGE =           ''''''    #Tool Change commands will be inserted before a tool change

#*********************************************************************************************************
# End of customization
#*********************************************************************************************************

# Parser arguments list & definition
parser = argparse.ArgumentParser(prog='grbl_G81', add_help=False)
parser.add_argument('--comments',           action='store_true', help='output comment (default)')
parser.add_argument('--no-comments',        action='store_true', help='suppress comment output')
parser.add_argument('--header',             action='store_true', help='output headers (default)')
parser.add_argument('--no-header',          action='store_true', help='suppress header output')
parser.add_argument('--line-numbers',       action='store_true', help='prefix with line numbers')
parser.add_argument('--no-line-numbers',    action='store_true', help='don\'t prefix with line numbers (default)')
parser.add_argument('--show-editor',        action='store_true', help='pop up editor before writing output (default)')
parser.add_argument('--no-show-editor',     action='store_true', help='don\'t pop up editor before writing output')
parser.add_argument('--precision',          default='3',         help='number of digits of precision, default=3')
parser.add_argument('--translate_drill',    action='store_true', help='translate drill cycles G81, G82 & G83 in G0/G1 movements (default)')
parser.add_argument('--no-translate_drill', action='store_true', help='don\'t translate drill cycles G81, G82 & G83 in G0/G1 movements')
parser.add_argument('--preamble',                                help='set commands to be issued before the first command, default="G17 G90"')
parser.add_argument('--postamble',                               help='set commands to be issued after the last command, default="M5\nG17 G90\n;M2"')
TOOLTIP_ARGS=parser.format_help()


#*********************************************************************************************************
# Internal global variables
MOTION_COMMANDS =   ['G0', 'G00', 'G1', 'G01', 'G2', 'G02', 'G3', 'G03'] # Motion gCode commands definition
RAPID_MOVES =       ['G0', 'G00']                                        # Rapid moves gCode commands definition
SUPPRESS_COMMANDS = ['G98', 'G80']                                       # These commands are ignored by commenting them out
COMMAND_SPACE = " "
CURRENT_X = 0 # Global variable storing current position
CURRENT_Y = 0
CURRENT_Z = 0
#*********************************************************************************************************


# to distinguish python built-in open function from the one declared below
if open.__module__ in['__builtin__','io']:
  pythonopen = open
#pythonopen = open

def processArguments(argstring):

  global OUTPUT_HEADER
  global OUTPUT_COMMENTS
  global OUTPUT_LINE_NUMBERS
  global SHOW_EDITOR
  global PRECISION
  global PREAMBLE
  global POSTAMBLE
  global TRANSLATE_DRILL_CYCLES

  try:
    args = parser.parse_args(shlex.split(argstring))
    if args.no_header:
      OUTPUT_HEADER = False
    if args.header:
      OUTPUT_HEADER = True
    if args.no_comments:
      OUTPUT_COMMENTS = False
    if args.comments:
      OUTPUT_COMMENTS = True
    if args.no_line_numbers:
      OUTPUT_LINE_NUMBERS = False
    if args.line_numbers:
      OUTPUT_LINE_NUMBERS = True
    if args.no_show_editor:
      SHOW_EDITOR = False
    if args.show_editor:
      SHOW_EDITOR = True
    PRECISION = args.precision
    if args.preamble is not None:
      PREAMBLE = args.preamble
    if args.postamble is not None:
      POSTAMBLE = args.postamble
    if args.no_translate_drill:
      TRANSLATE_DRILL_CYCLES = False
    if args.translate_drill:
      TRANSLATE_DRILL_CYCLES = True

  except:
    return False

  return True


# For debug...
def dump(obj):
    for attr in dir(obj):
        print("obj.%s = %s" % (attr, getattr(obj, attr)))


def export(objectslist, filename, argstring):

  if not processArguments(argstring):
    return None

  global UNITS
  global MOTION_MODE

  print("Post Processor: " + __name__ +" postprocessing...")
  gcode = ""

  # write header
  if OUTPUT_HEADER:
    gcode += linenumber() + "(Exported by FreeCAD)\n"
    gcode += linenumber() + "(Post Processor: " + __name__ +")\n"
    gcode += linenumber() + "(Output Time:"+str(datetime.datetime.now())+")\n"

  # Write the preamble
  if OUTPUT_COMMENTS:
    gcode += linenumber() + "(begin preamble)\n"
  for line in PREAMBLE.splitlines(True):
    gcode += linenumber() + line
  # verify if PREAMBLE have changed MOTION_MODE or UNITS
  if 'G90' in PREAMBLE:
    MOTION_MODE = 'G90'
  elif 'G91' in PREAMBLE:
    MOTION_MODE = 'G91'
  else:
    gcode += linenumber() + MOTION_MODE + "\n"
  if 'G21' in PREAMBLE:
    UNITS = 'G21'
  elif 'G20' in PREAMBLE:
    UNITS = 'G20'
  else:
    gcode += linenumber() + UNITS + "\n"

  for obj in objectslist:
    # Debug...
    #print("\n" + "*"*70)
    #dump(obj)
    #print("*"*70 + "\n")
    if not hasattr(obj,"Path"):
      print("The object " + obj.Name + " is not a path. Please select only path and Compounds.")
      return

    # do the pre_op
    if OUTPUT_COMMENTS: gcode += linenumber() + "(begin operation: " + obj.Label + ")\n"
    for line in PRE_OPERATION.splitlines(True):
        gcode += linenumber() + line

    # Parse the op
    gcode += parse(obj)

    # do the post_op
    if OUTPUT_COMMENTS: gcode += linenumber() + "(finish operation: " + obj.Label + ")\n"
    for line in POST_OPERATION.splitlines(True):
        gcode += linenumber() + line

  #do the post_amble
  if OUTPUT_COMMENTS: gcode += linenumber() + "(begin postamble)\n"
  for line in POSTAMBLE.splitlines(True):
    gcode += linenumber() + line

  #show the gCode result dialog
  if FreeCAD.GuiUp and SHOW_EDITOR:
    dia = PostUtils.GCodeEditorDialog()
    dia.editor.setText(gcode)
    result = dia.exec_()
    if result:
      final = dia.editor.toPlainText()
    else:
      final = gcode
  else:
    final = gcode

  print("done postprocessing.")

  #write the file
  gfile = pythonopen(filename,"w")
  gfile.write(gcode)
  gfile.close()


def linenumber():
  global LINENR
  global LINEINCR
  if OUTPUT_LINE_NUMBERS == True:
    s = "N" + str(LINENR) + " "
    LINENR += LINEINCR
    return s
  return ""


def format_outstring(strTbl):
  global COMMAND_SPACE
  # construct the line for the final output
  s = ""
  for w in strTbl:
    s += w + COMMAND_SPACE
  s = s.strip()
  return s


def parse(pathobj):

  global DRILL_RETRACT_MODE
  global MOTION_MODE
  global CURRENT_X
  global CURRENT_Y
  global CURRENT_Z

  out = ""
  lastcommand = None
  precision_string = '.' + str(PRECISION) +'f'

  params = ['X','Y','Z','A','B','C','I','J','K','F','S','T','Q','R','L','P']

  if hasattr(pathobj,"Group"): # We have a compound or project.
    if OUTPUT_COMMENTS: out += linenumber() + "(compound: " + pathobj.Label + ")\n"
    for p in pathobj.Group:
      out += parse(p)
    return out

  else: # parsing simple path
    if not hasattr(pathobj,"Path"): #groups might contain non-path things like stock.
      return out

    if OUTPUT_COMMENTS: out += linenumber() + "(Path: " + pathobj.Label + ")\n"

    for c in pathobj.Path.Commands:
      outstring = []
      command = c.Name

      outstring.append(command)

      # if modal: only print the command if it is not the same as the last one
      if MODAL == True:
        if command == lastcommand:
          outstring.pop(0)

      # Now add the remaining parameters in order
      for param in params:
        if param in c.Parameters:
          if param == 'F':
            if command not in RAPID_MOVES:
              outstring.append(param + format(c.Parameters['F'] * SPEED_MULTIPLIER, '.2f'))
          elif param == 'T':
            outstring.append(param + str(c.Parameters['T']))
          else:
            outstring.append(param + format(c.Parameters[param], precision_string))

      # store the latest command
      lastcommand = command

        # Memorise la position courante pour calcul des mouvements relatis et du plan de retrait
      if command in MOTION_COMMANDS:
        if 'X' in c.Parameters:
          CURRENT_X = c.Parameters['X']
        if 'Y' in c.Parameters:
          CURRENT_Y = c.Parameters['Y']
        if 'Z' in c.Parameters:
          CURRENT_Z = c.Parameters['Z']

      if command in ('G98', 'G99'):
        DRILL_RETRACT_MODE = command

      if command in ('G90', 'G91'):
        MOTION_MODE = command

      if TRANSLATE_DRILL_CYCLES:
        if command in ('G81', 'G82', 'G83'):
          out += drill_translate(outstring, command, c.Parameters)
          # Efface la ligne que l'on vient de translater
          del(outstring[:])
          outstring = []

      # Check for Tool Change:
      if command in ('M6', 'M06'):
        if OUTPUT_COMMENTS: out += linenumber() + "(begin toolchange)\n"
        if not OUTPUT_TOOL_CHANGE:
          outstring[0] = "(" + outstring[0]
          outstring[-1] = outstring[-1] + ")"
        else:
          for line in TOOL_CHANGE.splitlines(True):
            out += linenumber() + line

      if command == "message":
        if OUTPUT_COMMENTS == False:
          out = []
        else:
          outstring.pop(0) #remove the command

      if command in SUPPRESS_COMMANDS:
        outstring[0] = "(" + outstring[0]
        outstring[-1] = outstring[-1] + ")"

      #prepend a line number and append a newline
      if len(outstring) >= 1:
          out += linenumber() + format_outstring(outstring) + "\n"

  return out


def drill_translate(outstring, cmd, params):
  global DRILL_RETRACT_MODE
  global MOTION_MODE
  global CURRENT_X
  global CURRENT_Y
  global CURRENT_Z
  
  #global UNITS
  #global UNIT_FORMAT
  global UNIT_SPEED_FORMAT
  
  strFormat = '.' + str(PRECISION) +'f'

  trBuff = ""

  if OUTPUT_COMMENTS: # Comment the original command
    outstring[0] = "(" + outstring[0]
    outstring[-1] = outstring[-1] + ")"
    trBuff += linenumber() + format_outstring(outstring) + "\n"

  # Conversion du cycle
  # Pour l'instant, on gere uniquement les cycles dans le plan XY (G17)
  # les autres plans ZX (G18) et YZ (G19) ne sont pas traites : Calculs sur Z uniquement.
  if MOTION_MODE == 'G90': # Deplacements en coordonnees absolues
    drill_X = params['X']
    drill_Y = params['Y']
    drill_Z = params['Z']
    RETRACT_Z = params['R']
  else: # G91 Deplacements relatifs
    drill_X = CURRENT_X + params['X']
    drill_Y = CURRENT_Y + params['Y']
    drill_Z = CURRENT_Z + params['Z']
    RETRACT_Z = CURRENT_Z + params['R']

  if DRILL_RETRACT_MODE == 'G98' and CURRENT_Z >= RETRACT_Z:
    RETRACT_Z = CURRENT_Z

  # Recupere les valeurs des autres parametres
  #drill_Speed = params['F']
  drill_Speed = Units.Quantity(params['F'], FreeCAD.Units.Velocity)
  
  if cmd == 'G83':
    drill_Step = params['Q']
  elif cmd == 'G82':
    drill_DwellTime = params['P']

  if MOTION_MODE == 'G91':
    trBuff += linenumber() + "G90" + "\n" # Force des deplacements en coordonnees absolues pendant les cycles

  # Mouvement(s) preliminaire(s))
  if CURRENT_Z < RETRACT_Z:
    trBuff += linenumber() + 'G0 Z' + format(RETRACT_Z, strFormat) + "\n"
  trBuff += linenumber() + 'G0 X' + format(drill_X, strFormat) + ' Y' + format(drill_Y, strFormat) + "\n"
  if CURRENT_Z > RETRACT_Z:
    trBuff += linenumber() + 'G0 Z' + format(CURRENT_Z, strFormat) + "\n"

  # Mouvement de percage
  if cmd in ('G81', 'G82'):
    trBuff += linenumber() + 'G1 Z' + format(drill_Z, strFormat) + ' F' + format(float(drill_Speed.getValueAs(UNIT_SPEED_FORMAT)), '.2f') + "\n"
    # Temporisation eventuelle
    if cmd == 'G82':
      trBuff += linenumber() + 'G4 P' + str(drill_DwellTime) + "\n"
    # Sortie de percage
    trBuff += linenumber() + 'G0 Z' + format(RETRACT_Z, strFormat) + "\n"
  else: # 'G83'
    next_Stop_Z = RETRACT_Z - drill_Step
    while 1:
      if next_Stop_Z > drill_Z:
        trBuff += linenumber() + 'G1 Z' + format(next_Stop_Z, strFormat) + ' F' + format(float(drill_Speed.getValueAs(UNIT_SPEED_FORMAT)), '.2f') + "\n"
        trBuff += linenumber() + 'G0 Z' + format(RETRACT_Z, strFormat) + "\n"
        next_Stop_Z -= drill_Step
      else:
        trBuff += linenumber() + 'G1 Z' + format(drill_Z, strFormat) + ' F' + format(float(drill_Speed.getValueAs(UNIT_SPEED_FORMAT)), '.2f') + "\n"
        trBuff += linenumber() + 'G0 Z' + format(RETRACT_Z, strFormat) + "\n"
        break

  if MOTION_MODE == 'G91':
    trBuff += linenumber() + 'G91' # Restore le mode de deplacement relatif

  return trBuff


print(__name__ + ": gCode postprocessor loaded.")
actuate
Posts: 25
Joined: Mon Sep 23, 2019 8:47 pm

Re: grbl_81 unable to write gcode output file

Post by actuate »

I've been using this file as reference today:
https://github.com/FreeCAD/FreeCAD/blob ... bl_post.py

And then testing using CAMotics, all looked good until I moved to machine, at which point I find that Grbl not handle G81 codes etc.

So, having read aforementioned script file, I passed the argument "--translate_drill", and got an error.

Having the latest FreeCAD available for Fedora from repository, I downloaded the latest AppImage from the website, again got the same error (argument not found). Not having time to setup my own build yet I used the following to run the aforementioned script.



From:
https://forum.freecadweb.org/viewtopic.php?p=251015

If you want to create your own post processor you do the following:
- copy one of the existing post processors to your macro directory. You can set this directory in Preferences->General->Macro
- rename it so that it ends with "-post.py"
- modify it
- on next restart FreeCAD will offer you the new preprocessor.
Note: Don't use a hyphen (-), instead use an underscore (_), e.g filename: grbl_mine_post.py

Then copy / paste the aforementioned script, restart and then translate drill argument will work

:D Happy!
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