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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


About testability of OSP board

Bryan She

#28344

About testability of OSP board | 30 April, 2004

Hello all, these days I've met an OSP board testability issue. 1.OSP board 2.Solder paste:Kester R244 no clean paste 3.Print solder paste on test pad. Issue: There's brone(light yellow)flux residue on test pad,and the probe can't penetrate the residue to reach the pad. Is there anyone can give some advice or recommend some new NC solder paste that can leave only a few flux residue which provide good testability.

Thanks Bryan

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#28351

About testability of OSP board | 30 April, 2004

This issue is not "testability of OSP board". It is "testability of nc flux residue".

Kester [or some other flux suppler] can probably recommend a flux residue that is more probeable.

We have talked about the problems with probes getting gummed-up with nc flux res and corrective steps [other than changing flux] previously here on SMTnet. For instance, look here: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=4649

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Bryan She

#28360

About testability of OSP board | 30 April, 2004

Thanks

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#28364

About testability of OSP board | 1 May, 2004

Just to be use that we're heading in the correct direction, you're probing solder, not copper, correct?

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Bryan She

#28368

About testability of OSP board | 2 May, 2004

I'd thought that the solder on test pad can benefit our ICT,but in fact,the residue issue arised.I'd like to know how do you test your OSP board? Thanks Bryan

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#28369

About testability of OSP board | 2 May, 2004

You're correct. We prefer to probe solder, rather than copper, because the solder absorbs the impact of the probe better than copper and so, helps preserve the life of the probe.

Beyond that, OSP has a limited "shelf life". If the OSP is not coated with solder, it will corrode over time. Admittadly, for some products, corroded test pads is not a serious concern, after they're assembled.

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