Hi Joey - the IPC JSTD-001 committee is working on this topic currently.
The issue is complicated as X-ray assessment can reveal "lots" of things
that may or may not be defects. Since the IPC standards have been built
around visual assessment, integrating/evolving the new assessment
technologies such as X-ray takes some time/effort. Most folks use X-ray to
establish adequate process control and then phase the X-ray inspection into
a sampling activity. Depending on the type of electronics and industry
segment you are in, X-ray assessment can be a costly addition. For your
product, 100 % X-ray inspection may be value added if you can define what
constitutes a defect. Reworking/repairing non-defects causes more assembly
damage than it fixes. Very tough topic - watch for the JSTD-001 committee
to be providing more direction in the future.

Dave Hillman
Rockwell Collins
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On Mon, Sep 19, 2016 at 4:52 PM, Joey Rios <[log in to unmask]> wrote:

> Sections 7.5.14, 15 and 16 outlines inspection of hidden solder joints,
> invoking the use of X-Ray in the Space Addendum. The standard does not
> explicitly prescribe a sampling extent, so, if an assembly has dozens of
> the same device, like 50-100 say of such devices (such as a bottom
> termination component) on a single PWA, is the expectation (J-STD intent)
> that each of the replicate devices are inspected by X-Ray?? Is that what
> the industry practices, or is sampling commonly invoked, since the
> processing of the board is the same for the entire PWA??
>