Warren,

In a prior life, I had to bake out some hardware after aqueous cleaning.
This was primarily due to the hardware being used in a space application,
and Engineering / Program Management was afraid that the moisture from the
aqueous cleaning process would out gas in the vacuum of space (even with
conformal coating).

Certain components did have to be baked out after aqueous cleaning. Other
components could not be cleaned in an aqueous cleaner due to material
incompatibilities. To avoid this, we would put these parts and components on
after cleaning, and locally clean those components with IPA. I know the
arguments against local cleaning with IPA (moving / diluting the flux around
the soldered component vs. removing it), but for our application it worked
fine.

I would also suggest that if you could replace these components with
something more robust, it may remove the baking operation after cleaning.

Hope this helps.

Good Luck.

Lee Whiteman
Senior Manufacturing Engineer
E-Mail: [log in to unmask] <mailto:[log in to unmask]>
Ph: (610) 362-1200 x208
Fax: (610) 362-1290



> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of [log in to unmask]
> Sent: Friday, January 18, 2002 4:04 PM
> To: [log in to unmask]
> Subject: [TN] Baking of Assemblies?
>
>
> This should be good fodder! We wash PWAs in a water hurricane
> type machine, with
> a hot air blower at the end of cycle. We noticed some components
> mainly elect.
> alum. capacitors have high capacitance. After research on cap. we were
> instructed to bake assemblies 20 mins @ 100c to dry them. The
> long term effect
> of the moisture in the cap would cause electrical leakage then
> failure due to
> corrosion.
> Well this idea expanded into a question should we bake all
> assemblies because
> many other items such as transformers, pots., coils are not
> hermetically sealed.
> And then there is the issue with pwb material its self.
>
> My question to the forum is, Does anyone bake after wash as a
> standard? All
> points of view are welcome.
>
> Thanks!
>
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