The adoption of guidelines as specifications always has ambivalent results.
With the military abandoning the costs of maintaining their own internal
standards, it would be unfortunate if this results in North American
commercial design initiatives being hobbled critically.

The history of technical design standardization is one of repeated attempts
to automate the process. The idea, supposedly, is that you can remove the
human tendency for error. Ideally, all you really need to produce every
widget on earth is one engineer and a lot of machines, both no doubt
polished by hordes of well-trained, inexpensive, technical acolytes.

 Unfortunately, a surprisingly hefty chunk of invention and innovation is
prompted by just that human element; the smaller errors that may result and
their intelligent 'handling'. When extensively standardized, the tendency to
produce small random errors is not lost; instead it becomes systemic. This
can
generate potentially non-recoverable situations on a wide scale (e.g. the
atrophy of an entire industrial sector).

Let's not encourage anyone to turn guidelines into specifications, without a
good reason. You can always honestly say that you're following guidelines,
as guidelines, and still find out ways of getting more bang for the buck,
when it's possible.

Rob Legg
[log in to unmask]


----- Original Message -----
From: "Earl Moon" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 15, 2002 12:29 PM
Subject: Re: [TN] IPC SMT FOOTPRINT DESIGN GUIDLINES VS SUPPLIERS


> Jeff,
>
> Appreciate you time, input, and empathy. This story certainly is not new
but
> keeps getting more interesting and complex with time.
>
> I'm held accountable by my CM's if the solder joints do not meet IPC
> requirements. Ok, but I'm not able to directly correlate design guidelines
> with acceptance criteria in IPC requirement - not guidelines especially
now
> that DoD has adopted and, essentially, validated the specifications - not
> guidelines.
>
> Werner serves as chair on three committees and co chair on some more, I
> guess. The committees are composed of leaders in our industry putting
forth
> great stuff as I said before concerning design for reliability.
>
> Component suppliers make up their rules as well. All I'm saying is there
is
> a gap and it seems to be getting wider especially for one or two man/woman
> design teams tempted to go whichever way the wind blows whem enticed on a
> particlular day.
>
> Granted, there is much "slop" for forgiving designs, and the boards,
> components, and assemblies representing them. However, with things going
in
> the obvious direction, as smaller/denser, something needs more attention
and
> less emotion as your greatly accepted empathy. Still, for my young design
> team, I'm going all the way with IPC until proven wrong, or not.
>
> Earl
>
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