Richard, how were these (before and after) measurements made?  What uncertainties are there in the measurements?  I think of any measurement system as having uncertainty with 5 components:  repeatability, reproducibility, accuracy or bias, linearity, and stability.  I've seen engineers trying to solve problems that were nothing more than gage variation.  Please contact me off line or through TechNet if you need more info.  Lou Hart

----------
From:   Hamilton, Richard CLE 4454[SMTP:[log in to unmask]]
Sent:   Thursday, December 23, 1999 1:20 PM
To:     [log in to unmask]
Subject:        [TN] Packaging of PWB's

Hello all (or what there are of us out here!),

We have just completed an experiment on some PWB's that the results have me
a bit puzzled.

If you wrap bare boards individually in plastic bags at the manufacturer,
would it make sense that trace resistance would increase? Albeit in small
amounts, but a definite increase.

I cannot tell you if the bags are static bags or not, which would suggest to
me that they are not. Our results would seem to indicate that boards are
best shipped from the manufacturer after 2 weeks in a Temperature and
Humidity oven and after being exposed to oxidation.

Yea, I know, what in the world is going on with the experiment
process/method?? This sure seems to counter what might be considered as good
logic. Then again, maybe it is time for me to learn some more 'stuff' about
the care and feeding of boards!!

I have open ears, or eyes in the case of email!

Richard Hamilton
Clemar Mfg. / Rain Bird
[log in to unmask]

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