Bob,

Per IPC-A-600E, the answer is yes for outer layers and no for inner layers.  When measuring visually from
outer layers it annular ring includes the hole wall.  When measuring inner layer annular ring via
microsection, it includes only the inner layer pad and not the barrel of the hole.  See pages 45 and 72 of
IPC-A-600E.

Jay Soderberg


Legal Notice:  All opinions are mine and mine alone.  They do not necessarily reflect the opinions of the
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>   ------------------------------------------------------------------------
>
> Subject: annular ring
> Date: Mon, 15 Feb 1999 20:29:16 EST
> From: [log in to unmask]
>
> A customer has asked whether annular ring includes the plated thru hole
> barrel. I would appreciate any input that anyone has on this issue. Please e-
> mail to
> [log in to unmask]
>
> thank you for you help
>
> Bob Ko
>