I'm not able to comment as to whether the faults conform or not to the
tolerances permitted in the standards. However, if the photos are
typical of even one quarter of a batch, then I would return the lot to
the fab shop, willy nilly. There are two main problems, which may very
well have a common cause, to wit, contamination on the board when the
mask was applied. This is evident from the various inclusions, some of
which are a cause for rejection by any standard. The other is an evident
lack of adhesion over the tracks. Whether this is caused by a process
fault in applying the mask (e.g., poor insolation or development), it is
almost surely exacerbated by the fact that the mask does not 'stick' to
the conductors, despite the graininess of the metal, suggesting
inadequate cleanliness of the board. Whether this is because of, say,
inadequate rinsing after chemical or electrochemical treatments, or
whether it is because a foreign substance has somehow got itself on the
board, I cannot say. What I can say is that it appears that housekeeping
in the fab shop is sadly lacking if these examples are typical.
There is nothing you can do to help the situation, other than return at
least the faulty boards or the whole batch, as you decide.
Brian
On 29/12/2011 17:04, John Balchunas wrote:
> Greetings, and Thank you for your Counsel in the past.
>
>
>
> What I bring before you today are some photos of Soldermask from some
> PWBs in the as-received condition from the Supplier, and I would like to
> hear what you have to say as to their Conformance to IPC Class 2
> Requirements. It will provide the feedback I need to assess my own
> understanding of the criteria in IPC-A-600G and IPC-A-610E.
>
>
>
> The photos are in my Soldermask, Receiving Inspection Photos Gallery at
> the TechNet Group Site:
>
>
>
> http://ipc-technet.groupsite.com/gallery/22209?page=1
>
>
>
> Thanks again for your help with this.
>
>
>
> John Balchunas
>
> Supplier Quality Engineer
>
> Email: [log in to unmask]<mailto:[log in to unmask]>
>
> Tel: 763-278-2249
>
> Fax: 763-767-4635
>
>
>
>
>
>
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