Didn't want to come across harsh yesterday.
I know that's why most of you are on the council. You feel the same way and
wish to instill change.

Today I want to put a possible solution out there.
I can not say this is mine, but more a collection of what I hear and view to
be the problem
and the solution.

First, most of the confusion comes from, "how do the spec relate to the
fabrications specs."
Currently we may specify to the manufacturer, the class(or reliability) and
then the level (or complexity of the design) where these fall shot is there
are more than the 3 complexities
and they do not give the designer a full picture of what their limits are in
this level, nor
the manufacturer's limits or guidelines.

What is needed here is more levels of complexity with
clear definitions of technological limits per complexity (i.e. minimum trace
and space)
This in conjunction with the IPC spec to give the overall picture of the
requirements.

Of course, as pointed out by a nice lady, these have to be generic in
nature.
If given an adequate amount of technological levels a manufacturer can and
will
"buy into" the one that best suits their capabilities.

This would NOT constrain the manufacturer from making higher technology
boards,
and not limit the designer to those values, but give all of us a common
starting point.
What we know to expect. The manufacturer can build what ever they want, but
when you specify to build to IPC specs and a level
(standard, advanced, leading edge, state of the art) the manufacturer will
know what
you expect of them.

How many people calculate the internal ring by .005" of plating only to have
their board
house drill over and plate .006"? Yes we can specify the plating amount as I
currently do,
but I personally note or specify several things because the manufacturer
doesn't have a clear
list of the requirements.

This process would allow the designer to specify only the IPC spec, the
level of technology
and those values that exceed or deviate from the spec.

On my little site www.robertsondne.com (
http://robertsondne.homepage.com/files/Standards%20card.doc for the direct
link to the table) I have been working on a quick table of values that
I have collected.

Each section could give information on the subject (such as annular ring)
First, what it is.
Why
With a table of:
    The IPC specification
    The manufacturer requirements per technology.
(These values directly relates to the specification book the manufacturer
uses)
Recommended note for deviation

At the end of the specifications a summary/quick reference table with all
the values.
Also provide a recommended set of notes.

If you have any disagreements, by all means, lets talk.
If not, take this with you to you meetings. Discuss it...get it implemented.

This issues have been our problem, or complaint and this is the solution.
Plain,
clear, and concise.

Chris Robertson
[log in to unmask]
www.robertsondne.com
"The PCB Designer's Resource"

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