--- PicDude <picdude2@avn-tech.com> wrote:

> For a 2-layer board, I see 3 drill files created
> when I generate the gerber 
> (274X) files -- .dri, .drd, .drl.  This is what I
> see in there...

Depending on what process is chosen, you should go
about specifying non-plated holes differently.

For instance, with budget quickturn board houses, they
do not do a second drilling pass. So if you want
non-plated holes you take your chances and depending
on the process the specific board house uses, you may
or may not end up with those holes being plated(or
sometimes partially plated). What you do is create a
pad stack that has a zero size pad on both layers.
Then there is no conductive material at the hole and
it quite often doesn't get plated. But most quickturn
places do not guarantee that there will be no plating
in those holes, for obvious reasons since some of them
plate the holes at a different point in the process
and none of them want to guarantee something they are
not being paid extra for.

Now if you are willing to pay for those non-plated
holes, and your board house offers a second pass, you
can get genuine unplated holes. Every board house is
different(we are all humans) and you ask them and they
tell you what they want or need. Some are happy with
the zero-size pad and their software deals with it
automatically. But most will want either a drill
diagram or else separate drill files. The drill
diagram is the classic way of doing it but is more
suited to the old manual labor-intensive board
processes.

Ask your board house. And be prepared to pay extra if
you want that second pass. But you should sometime at
least try the zero-pad-size method and see if it works
at the places you frequent.

Cheerful regards,

Bob

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