Hi Ken,
In addition to what Ray Klein and Jerry Cupples have said, solid power and
ground planes without thermal relief spokes, will stress the PTH/PTV copper
barrels more than spoked planes or signal layers during the large z-direction
thermal expansion differences caused by soldering processes. PWBs with PTH/PTV
qualities on the hairy edge for the construction and processing sequence may
show barrel failures in the prepreglayer-are ajacent to the solid Cu-plane.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask]

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