Couldn't agree more. From a PWB manufacturer's point of view that is. Some
suppliers may indeed be able to do a little better than the 0.010" to
0.012", depends on the various process capabilities that determine their
ability to register the pad to the hole.

Bob Dube

-----Original Message-----
From: Joe Uhr <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, February 03, 2000 2:43 PM
Subject: Re: [TN] VIA pads


>Yvon,
>
>.010"-.012" over drill size is pushing the limit. .018" via (finished hole
>size, plated, I am assuming) would probably be drilled with a .024" drill
>bit, assuming a +/- .003" tolerance on finished hole size. .034" would then
>be the pad size. The PWB supplier would definitley let you know if that was
>a problem. That is why it is a good idea to involve suppliers in DFM
>reviews.
>
>JU
>
>
>-----Original Message-----
>From: Yvon Hache [mailto:[log in to unmask]]
>Sent: Wednesday, February 02, 2000 8:06 AM
>To: [log in to unmask]
>Subject: [TN] VIA pads
>
>
>Good morning everyones around the World,
>
>I have a design/manufacturing question.  If we use a 0,018" VIA, what is
the
>smallest pad size we can use on this VIA without causing problem in PCB
>manufacturing?
>
>thanks
>
>
>Yvon Hache, P.Eng.
>Tel: 506-863-2467
>Email: [log in to unmask]
>
>Concept + Inc.
>Scientific Park, Suite 100
>55 Crowley Farm Rd,
>Moncton, NB
>E1A 7R1
>
>Tel: 506-858-4153
>Fax: 506-858-4075
>Web: www.concept-plus.com
>
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