No way should anything, designed to be temporary, become permanent. Even
residues, after peeling, can be dangerous unless meticulously removed.
Donkey's years ago, I took a 10 cm x 10 cm board which had been
meticulously cleaned to near-zero ionic contamination. I then coated it
entirely on one side with a layer of peelable mask (and I tried it with
about 8 different makes). I allowed the mask to dry 24 hours, to be sure
that all volatiles had gone. I then carefully peeled off every visible
trace of the mask and done ionic contamination tests on each board. In
EVERY case, the ionic contamination had risen by some degree, mostly to
a quite dangerous level (exact figures lost in the mists of time). If
the invisible residues will do this, just imagine what visible residues
will do.
My answer is a categorical NO. In fact, I would go farther: peelable
masks should never be used in a "no-clean" situation (or after cleaning)
where quality and reliability are criteria to be respected (this will,
no doubt, hurt some, but it is my belief).
Brian
Dobbs, Marie wrote:
> I am looking for some feedback. We use Techform Liquid solder mask
> (peel able) to cover PTH on our PCA's.
> We also use this Mask as a "Tacking" mechanism to hold Loose Loaded
> (unsecured/not bent) components on the top side of the board. After the
> mask dries, we take it off the board. This is a Non-Value added
> activity that I would like to eliminate. I want to leave the dried
> masking on the board.
> My question is. Can I leave it on the board? Will it affect the long
> term function of the board? Do any of you use this, or do this? Any
> input is appreciated.
> Thanks
> Marie
>
>
> Marie A. Dobbs
> Training and Development Specialist
> Tyco Safety Products
> 100 Technology Drive
> Westminster, MA 01473
> Phone: 1-978-731-6827
> Fax: 1-978-731-6950
> email: [log in to unmask]
>
>
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