We use RMA solder paste exclusively and have many plastic parts in a very
wide variety of assemblies. Our boards go through a semi-aqueous wash. To
date we have had no such corrosion as you mention. We had been a relic of
the ceramic military industry...but now have a mix of new products using
plastic technology as well as legacy programs that use mostly ceramic.

At 12:54 PM 6/19/98 -0700, you wrote:
>Dear Technet,
>
>Fact or Fiction?
>
>Being a relic of military electronics assembly, I have always dealt with
>ceramic-encased microcircuits.  As we're starting to look at plastic
>encapsulated microcircuits (PEMs), some new assembly considerations
>arise.  One that we (technet) have covered lately is the moisture
>absorption, which I can understand.  Another concern that my folks are
>telling me is that these PEMs are subject to corrosion when soldered
>with rosin-based fluxes, even the RMA types, regardless of cleaning
>processes.  Other no-clean or water soluble fluxes are ok.  I am having
>trouble with this one.  Can anyone support or deny this notion?
>
>Thanks
>
>Ralph
>
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----

Jeffrey C. Guynn <[log in to unmask]> Phone: (219) 429-6345
Lead SMD Manufacturing Engineer        Fax: (219) 429-4688
Raytheon Systems Company M/S 25-31
1010 Production Road, Fort Wayne, IN 46808-4106

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