II. gcode preparing

For preparing the gcode I use the V-Bit Milling Fab Module Program from Jacopo Dimatteo
This is based on the fabmodules

Jacopo’s Fab Module works offline in a web browser. It’s only necessary to download and unzip the file.
But don’t use Firefox ! It doesn’t works ! I made the experience, that Google Chrome or the Chrome based Vivaldi Browser are good for this. There are still bugs with these, which I explain later.

milling the traces

starting

After starting the module in the browser, it looks like this

read file

Depending of what kind of PCB layout file you have, select the corresponding module for open the file.
The ready made Traces and Outline Cutout files are available as png.

Zoom to the read png , click select png file and choose the fts_mini_traces.png file

set mill tool

In the module set PCB defaults are some predefined mill-tools. For milling the traces I use a 1/64 tool, so I can just press the corresponding button.
If you use one which is not in the list, just skip this step.

adjust speed

In the next step take a look at path to G-code module and adjust the speed, matching to your machine. For my CNC3018 with the 1/32 mill tool, I choose 25mm/s for cut speed

cut depth and offset

We go ahead to the module mill raster 2D
There we can change the tool diameter if it was not in the predefined list above.
The cut depth depends on the PCB material which will be used. Just leave it as is and have look, how the result looks like. If there is copper left in the traces, raise the value a bit for deeper cuts.

The offset number defines, how many “unused” copper should be removed. Set it to 0 means, that ALL unused copper will be removed.
For the FabTinyISP it’s fine to set this value to 3 as suggested in the documentation and remove the copper stripe, in front of the usb header, with a knife.

Just press calculate and the gcode file will be generated and the download dialog appears. The file will be saved as fts_mini_traces.gcode

ATTENTION There is a bug in the module. When you would like to change some settings, after the download has started, it’s not possible to download the file with the changed settings again!
You have to refresh the page or, in worst case, to close the browser and open the module again.

offset example

For a better understanding I give here an example about the offset number
In the module offset you can see a preview.
Here are two examples. The first one is with an offset of 3 and the second one is with an offset of 7

You can see, that much more unnecessary copper will be removed.

milling the CutOut

Open the file fts_mini_cut.png as described above
For cutting the outline, I use a 1mm end-mill , so I just can press the corresponding button in the set PCB defaults module.

Measure the thickness of your PCB material and put the correct value in the mill raster 2D module

Is the value to less, the mill will not cut completely through the PCB.
Is it to high, you maybe mill into your buildplate !!!

Then press calculate and the file will be saved as fts_mini_cut.gcode

For security reasons, I’ll don’t provide prepared gcode files.
It can damage your machine !