Susan,
Thanks for the feedback.
Since the inner layers must be attached we would have to cross-section to see
if that were the condition, which would destroy the board anyway.
We are sure of the HASL stress as the cause first, by visual and later by cross-
section. It involved only thick (.200") boards. We solved the problem by baking
the boards for 4-8 hrs @ 300F, although we don't really know if the pullaway
was due to trapped moisture or the "shock" of HASL.
Joe


Quoting [log in to unmask]:

> Joe
> I have seen many microsections in years passed where the plating was
> stuck to
> the inner layers only and none to the laminate.  Inner layers must be
> attached.  Military specs still have a resin recession requirement "as
> received".  IPC specs evaluate after stress and therefore have dropped
> the
> consideration that resin recession is a defect.
>
> The theory being if there is no requirement after stress, then why have
> a
> limit before?
>
> Inner layers must be attached.
>
> How do you know the hole wall "explodes" or "delaminates" after HASL?
> Is
> this by microsection or visual assessment?
>
> Susan
>



Joseph Spicuzza
Quality Assurance Supervisor
Advanced Interconnect Products Division
Compunetics, Inc.
ph: 412 858-6166
fax 412 373-8060
[log in to unmask]

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