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Date: | Wed, 23 Apr 2003 10:46:02 +0300 |
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Carrie
My Smart answer: It all depends on the chemistry of the flux.
1. Alcohol will not react chemically with the residues.
2. Some "no-clean" fluxes may encapsulate activators in a matrix and
alcohol can decapsulate by dissolving the matrix and not necessarily the
activators which may have polymerised with the soldering heat.
3. Ionic contamination testing a "no-clean" flux, which is not cleaned,
is absolutely meaningless in absolute terms.
4. Ionic contamination testing a "no-clean" flux, which is not cleaned,
may be used to determine the consistency of a process in relative terms.
IOW, if you determine the mean and standard deviation for a single board
design, any subsequent consistent change, **in either direction** will
mean that the process has derailed.
Brian
Morse, Carrie wrote:
> This question goes out to all those with No-Clean Chemistry Experience -- Especially
> those who manufacture No-Clean Paste, Flux, and Cored Wire.
>
> Once a circuit card assembly has been assembled and soldered with No-Clean
> products .... Assuming (I know I know...) that the fluxes have been fully activated,
> what type of results should I expect to see....Assuming....that the boards and components were
> "clean" prior to assembly.
>
> More specifically, will Alcohol "reactivate" the no-clean flux or "free" contaminants that will
> register on the Omega Tester?
>
> -Carrie
>
> P.S. And No smart remarks like "How clean is clean" and "You know what happens when you assume".
>
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