PCB-GCODE is specifically designed to covert an Eagle PCB design into GCODE for isolation routing.  It is written and maintained by John Johnson.

www.pcbgcode.org/ groups.yahoo.com/group/pcb–gcode

  1. Design your board in Eagle
  2. Convert to GCODE with PCB-GCODE
  3. Run GCODE through an autoleveller
  4. Mill your PCB

Of course, there are a lot of ‘sub steps’.

PCB-GCODE installation

Download PCB-GCODE from the downloads section of the forum.

PCB-GCODE configuration

Calculating Tool Width

Drill Rack

This is a super-handy feature of PCB-GCODE.  The challenge is that the component designs in Eagle have a massive range/array of hole sizes, so that a single board can have 20-50 different diameters of holes.  This is simply not practical.  Not just the drill inventory, but the number of tool changes would make you crazy. The Drill Rack feature allows you to define the drill diameters you have available and the range of diameters for which a specific drill diameter can be substituted. Here is my low-tech Drill Rack, populated based on my needs and experience.

Example of a basic Drill Rack

Example of a basic Drill Rack

My rack contains

1.   0.0236in
2.   0.0320in
3.   0.0400in
4.   0.0453in		 5.   0.0625in
6.   0.0938in
7.   0.1250in  (currently loaded in my milling machine)
8.   Milling bit (60 degree)

Here is the contents of my drill rack file (DrillRack_1.drl):

tool   drill_size    minimum    maximum    length
T01    0.0236in      0.000in    0.025in    1.5in
T02    0.0320in      0.025in    0.035in    1.5in
T03    0.0400in      0.035in    0.045in    1.5in
T04    0.0453in      0.045in    0.055in    1.5in
T05    0.0625in      0.055in    0.080in    1.5in
T06    0.0938in      0.080in    0.100in    1.5in
T07    0.1250in      0.100in    0.200in    1.5in

Important - must use TAB character, not spaces
In the table above, it is CRITICAL to use TABs between all the elements, NOT spaces.  To make the above chart work in WordPress, I needed to use spaces.
Including the unit of measurement (e.g. “in”, “mm”, “mil”, etc) is optional, but it would be dangerous to leave them out.  For the extra 20 seconds of typing, put in the unit of measurement to avoid any problems.  You can mix-and-match different units in a single drill file. More information and details are in the PCB-GCODE users manual and some hints are in the sample, template drill rack file  default.drl.txt (located in the settings directory)

 

Placing Text on your PC Board

I have found two ways to include text on your PC board.  Engraving and milling.  I have been using the milling option, but I prefer engraving.  The two approaches look completely different.

Fonts must be VECTOR
Regardless of which approach you choose, the font must be set to VECTOR

VectorFonts

Milling Text

Milling text involves putting the text (as vector font) on either the top or bottom of the PC board – along with the traces.  The lettering will be “isolation milled” exactly like traces.  About half the time I manage to machine away most of the text.

Example of "milled" text

Example of “milled” text

 

Engraving Text

TBD

Double-sided PCB milling

TBD

[move to milling page] Drill bits

[move to milling page]Ring or no ring

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