Kevin:

We have no problem with 1uf caps (TANT). Thus I suspect:
1-      thermal shock
2-      too long a time in the wave >2 s

I would not suspect moisture if the boards have already been thru a reflow
oven and have not sat long.

Chris

        -----Original Message-----
        From:   Kevin Stokes [SMTP:[log in to unmask]]
        Sent:   Thursday, August 16, 2001 4:26 PM
        To:     [log in to unmask]
        Subject:        [TN] To wave or not to wave, that is the question...

        Old problem: mounting ceramic capacitors to the bottom side of an
assembly and your customer wants you to wave them on.

        We are having problems with 0805 0.22 uF and 0.1 uF caps going
through wave and cracking during the process.  We are following all of the
standard protocols (preheat, etc.).  My understanding is that 0805s are
typically capable of handling this process.

        Anyone got any ideas short of moving the cap to the top or doing a
double sided reflow?

        Kevin

        Kevin Stokes
        Reliability Manager
        Kimball Electronics Group
        (812) 634-4207


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