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Date: | Fri, 23 May 1997 14:02:49 -0500 (CDT) |
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We are planning to do a study on dimensional stability of pwbs. Right now
our focus is on the laminate material and cores. We are seeing different
amounts of shrinkage depending on design complexity, cloth type, copper
etc...In addition this shrinkage appears to be inconsistent from lot to lot.
We understand that resin content of prepreg is a factor.
In reference to Printed Circuts Handbook by Coombs (sec. 23.2.3) 40-60 %
resin content by weight is desirable. What happens to dimensional
stability if we go outside that range? What kind of SPC are you doing to
control resin content?
We would also like to know what the main variables in prepreg
fabrication (relative to dimensional stability) are, and how the rest of
the industry is controlling these variables.
All input is highly appreciated.
Chris Davison
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