gEDA-user: Preliminary report on gerbers with buried, hidden and micro vias

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

I promised to ask my fab shop about buried vias and how they are
presented in the gerber files.

Today PCB produces two cnc reports. The first is for un=-plated  holes
the second is for plated vias and pins.

The rules for buried, blind and micro vias according to my fab shop are.

You can't mix layers. If you have buried via connecting layers 2, 3, and
4 you then can not have buried vias connecting layers 3, 4 and 5.
This is because they will build up the layers 2, 3, and 4 as if it was
its own board. Drill and plate the holes for them. Next they add the
other layers to make the complete board. Then they drill and plate all
the normal vias.

The way to present this information is with separate CNC files for each
group of layers. In my example:

A cnc file for all regular vias and pin holes.
A cnc file for the non-plated holes
A cnc file for layers 2, 3 and 4 which only include the buried vias