We have had continual problems with "metallized film chip capacitors"
expanding after going through a wash cycle and then the board going through
wave solder.  I understand that these capacitors are not encased or
completely sealed--as are ceramic chip caps--my question is sort of
two-fold.  1. Does anyone have recommendations as to another material that
may have similar properties as the metallized film (my engineers have
mentioned the superior low microphonics of the metallized film)? and 2. Has
anyone had similar experiences and developed a workaround or solution to
this problem.  One last note is that we are following the manufacturer's
specs for reflowing these caps, but we get into trouble when the boards
(which need to be washed due to a water-soluble flux) have to subsequently
go through a wave cycle and the trapped moisture from our wash process
expands, popping the little suckers.  Any help is much appreciated.

Chad Thibodeau
Component Engineer
[log in to unmask]
2114 W. 7th Street
Tempe, AZ 85281
P-602 333-2138
F-602 921-9012
http://www.efdata.com

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