Robert
Some suggestions
Compare a Tg of as received laminate with the finished board. Lower Tg of
finished board indicates undercure in your press
What glass styles are you using in the prepreg. Is there more resin and less
glass in the prepreg layers compared to the laminate, facilitating expansion
there?
Have you checked the stress level on the plated copper?
Good Luck
Jerry Sallo
Sallo Consulting Services

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