Dear Charlie and TechNet,

Thank you for your "thank yous"; and thank you to everyone else who
contributes, in one fashion or another. And last, I am still learning, so
feel free to engage me or re-educate me ....

Just a few comments to your last email, one a correction of sorts, and the
other some rumblings ..

It was not my intention to characterize any portion of the supplychain as
being uncooperative or unsupportive of the challenges of the next layer
along the chain; in fact, it's the opposite: quite a bit of what I have
come to know has come from other segments of the supplychain. The problem
I meant to elaborate was related to the peculiarities of "testing" for
"something" not even agreed to.

Testing is a very special endeavor; I am not a test engineer or a Quality
Engineer, or a Statistician, nor do I have any particular training in the
specialties and sub-specialties of "testing" - but I have a lot of respect
for those who do, because it is not at all simple.

I happen to be in the same "camp" as yourself, which is that we need a
coupon to test  the response of the PCB to the actual assembly profile, or
as close as
possible, prior to committing valuable and sometimes hard-to-get
components to the PCB. There are 2 companies moving to develop such a
coupon, that I know of; and many others who also agree with this ideal.

Just to note the other possible position: that there are certain tests or
a combination of tests for which acceptable performance levels can be
established, and those results would indicate suitability for LFA. I think
this type of testing is needed and useful to initially characterize a
material and then to track it over time; also to compare materials'
loosely to each other; but I do not think it is sufficient to predict a
PCB's capability to survive any and all designs for any and all lead free
profiles. I think that the laminators would agree. Also bear in mind that
when it comes to testing for product compliance and/ or product usage,
lawyers inevitably get involved.

As a side note, what started me down the path of the "coupon as indicator"
solution, is the study of the test methods and a review of the data
sheets; this then led me to believe that much more standardization is
necessary, if in fact it is possible. Also, we must keep in mind, that
tests for laminate properties are typically done on laminates that have
not been processed into PCBs (with holes etc) because that is the only way
to keep the variables under test to those which are wholly incorporated by
the laminate. And I'm OK with that; it's a fact of good test design; we
just need to be aware of it. Which is why, tests on laminates, are
indicators but not predictors of possible response to potential reflow
profiles.

On an entirely separate note, I believe some of the items which have had
more significant negative impact on our industry are macro-economic,
governmental, and accounting and capitalization. Yes there are some
knuckle-heads and some old-school divisions, but for the most part those
haven't been the biggest problems.

Cheers,

Valerie

----------------------------------------------------------------------
Good Afternoon Valerie:

Your response and expertise relative to this subject is most appreciated.

As one whose interest lies in those designs incorporating high end flex
rigid and rigid, I will stipulate to the "suggestion" by UL to consider
the
pcb "industry" suggestion to go to a 288C test as a starting point
relative
to a new coupon strategy to show compliance with LF and RoHAS standards.

I agree with the multiplicity of laminate/component/assembly issues that
you
pose below as being broader in their implications as to determining the
temperature capability of bare laminate.

As suggested earlier, the method for success in the new N-L world would be
to meet these high heat exposure challenges through a co-operative
engineering mode..namely, if you know there are high heat parts in the
assembly, the correct material can thusly be anticipated and identified
for
use.

The notion that we should continue the bunker mentality of defending our
particular discipline (read: fabricators) while accepting no
responsibility
or understanding of the subsequent impact of follow on processing (read:
component choice and assembly process) is a recipe for failure going
forward.

We must breakdown these provincial barriers between disciplines and allow
those in research, design, manufacturing and processes, both vendor and
end
user, to work as a team, as one entity. Thusly we will foresee problems of
production and in use that may be encountered with the product.

It is my view that the time is now to put into place such protocols that
will allow such interaction.

The one requirement is that customers, upon choosing vendors of like mind,
must work in a mode of "open kimono communication" to achieve success. The
time for self-righteous protection of so-called manufacturing secrets that
hindered open manufacturing discussions has hurt our industry.

I truly believe that one method of common ground would be a coupon
approval
structure that would ensure that materials chosen would perform at the
level
the particular assembly would require. The result, in my opinion, is one
in
which we all would enjoy higher profitability and long term success along
with job stability for all (of those left!) in the pcb industry in the US.


Charlie McMahon
McMahon Sales Company

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