Tom -

    I don't recommend using polyimide as a standard for the following
reasons:

1.      Cost -- the last time I checked polyimide was 20-50% more than FR-4
2.      Fabricators -- not all fabrication houses can produce polyimide
boards requiring you to qualify more suppliers.
3.      Assembly issues - polyimide seems to require more process control
than FR-4 to achieve the same results ( pre-bake, etc.)

If you need dimensional stability over a wide temperature range, I suggest
you look at G-tek or other tetra-functional FR-4 materials they may be a
better choice.

Jeffrey McGlaughlin
Designer
Battelle Memorial Inst.
 Columbus Ohio

        -----Original Message-----
        From:   Tom Lambert [SMTP:[log in to unmask]]
        Sent:   Friday, March 13, 1998 4:58 PM
        To:     [log in to unmask]
        Subject:        [TN] FR4 vs Polyimide

        >
        >Am trying to decide which to standardize on - would appreciate
info, pros
        >and cons, for each.
        >


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