How to mill a PCB

Example

Export the Gerber files

Use pcb2gcode

Create a file named millproject

# This is an example config file for pcb2gcode.
# Rename this file "millproject" and place it in the same directory as your
# gerber files to save typing
# <option>=false is implicit, it is present just for clearness

# You may want to uncomment and change those in local project files (or you
# can specify them directly as command line arguments)
#front=led_copperTop.gtl
back=led_copperTop.gtl
outline=led_contour.gm1
drill=led_drill.txt
#preamble=preamble.ngc
#preamble-text=preamble_text.txt
#postamble=postamble.ngc

# Common options
metric=true
metricoutput=true
#mirror-absolute=false
#optimise=true
zchange=2.0000
#zero-start=true
zsafe=2.0000

# Mill options
#extra-passes=0
mill-feed=60
mill-speed=20000
offset=0.400
#offset=20  # Uncomment (and comment the previous line) for voronoi regions
zwork=-0.700

# Drill options
drill-feed=200
#drill-side=auto
drill-speed=20000
#milldrill=false
nog81=true
#onedrill=false
zdrill=-2.0

# Outline options
#bridges=0.5000
#bridgesnum=2
cut-feed=60
#cut-side=auto
cut-infeed=20.0000
cut-speed=20000
cutter-diameter=1.5000
#fill-outline=true
#zbridges=-0.6000
zcut=-2.000

# Autoleveller options
#al-back=false
#al-front=false
#al-probefeed=100
#al-x=15.0000
#al-y=15.0000
#software=LinuxCNC

Run pcb2gcode in the same folder (https://github.com/pcb2gcode/pcb2gcode)

pcb2gcode

Clean Up G-code Files

As write in https://www.baldengineer.com/kicad-to-x-carve-pcb-workflow.html clean up gcode files (see section 5)

Milling

back.ngc file:

remove G64 line
remove M0 lines
Remove M2 line at the end of the file

Drill

drill.ngc file:

Remove M6 lines
Remove M0 line
Remove M2 line at the end of the file

Outline

outline file:

remove G64 line
remove M0 lines
Remove M2 line at the end of the file

Here is a Python script to remove all files

# ChatGTP code ;-)
# 17/12/2023

import sys
import shutil

def remove_unwanted_lines(file_path):
  # Dictionary of codes to be removed
  removed_lines = {"M0", "M6", "G64", "M2"}

  # Read lines from the input file
  with open(file_path, 'r') as file:
    lines = file.readlines()

    # Filter out unwanted lines
    filtered_lines = [line for line in lines if not any(line.strip().startswith(code) for code in removed_lines)]

    # Write filtered lines back to the same file
    with open(file_path, 'w') as file:
      file.writelines(filtered_lines)

    # Print the number of lines removed for each code
    for code in removed_lines:
      count = sum(1 for line in lines if line.strip().startswith(code))
      print(f"{count} lines starting with {code} have been removed.")

if __name__ == "__main__":
  # Check if the correct number of command-line arguments is provided
  if len(sys.argv) != 2:
    print("Usage: python script.py input_file.gcode")
    sys.exit(1)

    # Get input file path from command-line arguments
    input_file_path = sys.argv[1]

    # Create a backup of the input file
    backup_file_path = input_file_path + ".bak"
    shutil.copyfile(input_file_path, backup_file_path)

    # Call the function to remove unwanted lines
    remove_unwanted_lines(input_file_path)

Zero!

At each step, set the Z origine (with probe)

On Mac OSX :

Use CAMotics app. to preview gcode files
Use Universal GCode Sender to mill the PCB

Mill

La gravure se déroule en 3 étapes :
- Gravure avec la pointe javelot 1 dent 30° EVOMAX.
  Vitesse de rotation : 20.000 tr/min ou plus.
  Avance : 300 mm/min
- Perçage avec un forêt de 0.8mm et / ou 1mm
- Détourage du circuit avec la fraise "coupe diamant" :
  Vitesse de rotation : 20.000 tr/min ou plus
  Avance : 250 mm/min (avance plus importante possible sur machine rigide)
  Fraisage : en avalant

Results

Memo!

Mill

Genmitsu 10Pcs Nano Blue Coat Engraving Bits, 20 Degree 0.1mm Tip 1/8" Shank Conical V-Bit

Pack pour la gravure de circuits imprimés par CNC
Gravez vos circuits imprimés avec votre fraiseuse numérique.
Gravure à l'anglaise.
Ce pack contient tous les outils nécessaires pour réussir la gravure de vos PCB !
Diamètre de queue des outils du pack : 3.175 mm.
Le pack contient :
- 1 pointe javelot 1 dent à 30° 0.1mm série EVOMAX, outil idéal pour la gravure des circuits imprimés !
- 2 forêts de 0.8 mm.
- 1 forêt de 1.00 mm.
- 1 fraise "coupe diamant" carbure 1.50 mm.

La gravure se déroule en 3 étapes :
- Gravure avec la pointe javelot 1 dent 30° EVOMAX.
Vitesse de rotation : 20.000 tr/min ou plus.
Avance : 300 mm/min
- Perçage avec un forêt de 0.8mm et / ou 1mm
- Détourage du circuit avec la fraise "coupe diamant" :
Vitesse de rotation : 20.000 tr/min ou plus
Avance : 250 mm/min (avance plus importante possible sur machine rigide)
Fraisage : en avalant

Epaisseur PCB : Épaisseur: env. 1,5 mm. Coppe 0.035mm