Brian is exactly correct. But you must remember if you are not RINSING the
saponifier correctly you are not removing the flux as well. The flux will add
to the level of corrosive and hygroscopic residue. If saponifier is left on
it will be a easy removed if water can get to the area. We find with QFN
and other low standoff devices that flux, saponifier and water are left under
these components and they cause performance problems such as leakage, and
dendrite growth. Many of today saponifiers are not as difficult to clean as the
original terpene D-limonene cleaners would take multiple rinses to completely
remove the material. The residue left after cleaning if not properly rinsed
with clean water can cause leakage and corrosion problems.
Terry Munson
Foresite
765-457-8095
In a message dated 5/6/2008 2:08:55 A.M. Eastern Daylight Time,
[log in to unmask] writes:
I would say you have a problem. Saponifier usually has, inter alia, two
components, an amine and a surfactant. The amine, commonly
monoethanolamine, is ionic and the surfactant is commonly an ethylene
glycol or similar. The latter has a low vapour pressure and is
hygroscopic (and this generally applies to all surfactants, even if the
chemistry family is different. It can also form a matrix which can hold
the amine in suspension, slowing down iôts evaporation.
The idea of leaving hygroscopic residues is anathema to me. If they are
mixed with an ionic residue, it is double anathema.
IMHO, and in my experience, saponifier cleaning MUST be followed, not by
a simple rinse cycle, but by a full wash and rinse cycle, exactly as if
it were a water-soluble flux.
Brian
- bogert wrote:
> May 5, 2008
>
> I have the following question: If a saponifier is used with a DI
> cleaning machine to clean PWAs and the cleaning does not remove all
> traces of the saponifier, is there any concern, including sugsequent
> exposure, to a humid environment? Any technical reports on this subject?
>
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