We build boards for space and they must be bonded and riveted to rigid
aluminum frames to withstand the environments. We currently specify the
IPC-6012 requirements which are 0.75% bow and twist.

There is a concern that we may need to specify 0.5% bow and twist to prevent
1812 and possibly 1206 ceramic capacitors from developing cracks after the
boards are attached to the frames.

With our boards, .75% translates to a maximum of 45 mils of bow and twist.
Any thoughts on problem areas?

The boards are normally .090 thick, 8-12 layers and polyimide.


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