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Reply To: | TechNet E-Mail Forum. |
Date: | Fri, 14 Jul 2000 12:02:55 +0300 |
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Phil
You have brought up what is essentially an SME question and a good one, at that. I
don't know the specific mask you use but, being peelable, I'm assuming it is a
PVA/latex type in an aqueous base (possibly with a slightly ammoniacal odour?). The
choice of this kind of mask may be critical where "no-clean" techniques are practised.
I am not saying that your mask or any other specific makes are bad, but ***some*** of
them may leave dangerous levels of ionic contamination under some conditions of use. I
therefore recommend caution and qualification. Of course, if such masks are peeled off
before any form of cleaning using any aqueous technique, then these residues are very
effectively removed. If they are peeled off afterwards, beware (quite apart from the
accidental peeling in the cleaning machine clogging the filters!)!
When you emerge from the dark ages into the Renaissance, you may care to consider
soluble temporary solder masks, although they are not without some disadvantages as
well as great advantages. Again, you have to choose the one that best suits your
overall process.
Best regards
Brian
Phil Nutting wrote:
> Hi,
>
> We currently use Chemask CM8 for masking our through hole boards. Our
> process uses rosin flux for hand solder and no clean alcohol based flux in
> the wave solder system. At present we peel the mask off after wave solder.
> Post wave cleaning (after the non-waveable parts have been inserted) is by
> hand using alcohol. We do not yet have an aqueous clean system. Yes we are
> still working in the dark ages, but I'm working on that slowly.
>
> I'm interested to find out what other people use and why?
>
> Regards,
>
> Phil Nutting
> Manufacturing Engineer
> Kaiser Systems, Inc.
>
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