Page 11 - Building A Succesful Board-Test Strategy

Preface to the

Second Edition

When I wrote the first edition of Building a Successful Board-Test Strategy, my
intent was to avoid (as much as possible) the malady that plagues many books in
our industry: like the products they deal with, they become obsolete before release
to the public. To accomplish this goal, the book discussed tools, alternatives, and
ways to evaluate and select test strategies, rather than dictating what those strate-
gies should be.
In many respects, I succeeded. Most of the comments in the original edition
are as true today as when they were written. Nevertheless, the industry refuses
to stand still. Test has undergone something of a transformation in the past few
years. The migration of production capacity away from traditional manufacturers
toward contractors continues to accelerate. Today's army of contractors ranges
from "garage shops" catering to complex very-low-volume products to multi-
billion-dollar megaliths handling board volumes in the millions. This continuing
evolution brings with it new challenges, the most significant of which is how to
select a contract manufacturer. Such vendors are not like commodity products. As
with pieces of test equipment, contractors offer a wide range of strengths and areas
of expertise. Choosing one requires finding a combination of skills and capabili-
ties that best matches your needs. Discussions throughout the new edition take this
trend into account.
One development that I missed completely in the first edition was the plague
that open circuits bring to our surface-mount world. Hidden nodes, board copla-
narity (flatness), and other characteristics of today's boards require another look
at test methods. A new section of Chapter 2 explores these issues.
The concept of what constitutes a "test" strategy is evolving as well. Various
forms of inspection, once mere adjuncts to the quality process, have become inti-
mately linked with more traditional forms of conventional test. Then, too, inspec-
tion is not a single technique, but in fact a menu of approaches, each of which has
advantages and drawbacks. The new Chapter 3, "Inspection as Test," examines this
solution in considerable detail.
This new edition also updates information in many places, adding examples
and figures to prior discussions. Much of the additional material comes from
seminars that I have given in the past few years—both my own work and material