Hi Collin & MoonMan,
The high Tg actually is much more important during the assembly processes,
particularly manual soldering, than in field operation. Remember, the solder
process excursions are all above Tg, but how much above the Tg can make the
difference between barrel cracks and no barrel cracks.
Also, the glass transition region of the epoxies used for FR-4 starts about
25C below Tg; thus, merely stating that "the end use application is less than
Tg" is inadequate.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 386-437-8747, Fax: 386-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com

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