Davis Ben wrote:
>
> Greetings fellow designers...
>
> A question has come up concerning the need for pads on both sides of the
> board for a plated via.  We have slipped and let a via get placed under
> a metalized part (big OOPS).  Now we are in the fix it phase and would
> rather not take the time or money to scrap and re-layout the board.
> What we would rather do is remove the pad on the top side of the board.
>
> I have always believed the need for pads on both sides of the board is
> mostly a fabrication issue to insure good/complete plating on the hole
> wall (at least on vias).
>
> My questions are:
>
> 1) What problems arise if the top pad is removed from the artwork?

Not sure.

> 2) What problems would there be if the pad was removed after
> fabrication?

You mean scraping it off?

> 3) Any other suggestions.

See below.

> Thanks in advance for your help and responses.
>
> Ben Davis
> [log in to unmask]

Hi Ben,
would it be possible for you to make the one via tented?
(i.e. covered by solder mask)  What about tenting all your vias?
If not, can you put some insulator tape on the via that is a
problem?

I never tried making a via without a pad on either external layer,
but you should ask your PCB fab shop and see what they say about
removing just that one pad from the Gerber data during their
CAM set-up.   Should not be much of a problem, but for the
reliability of that one via.

 Regards
 Eric Bonatti

 << UBI MAJOR, MINOR CESSAT >>
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 Eric Bonatti - Printed Circuit Board Design
 GN Nettest (CANADA) Datacom Division
 phone: 905-479-8090 xt.497 / fax: 905-475-6524
 email: [log in to unmask]
 web:   http://www.nettestca.gn.com
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