Steve,
Based on what I'm seeing on the TechNet, it looks like your next step is to
have a few of the holes cross sectioned. If there is a straight hole wall
and well plated copper, you have another piece of ammo to defend using the
boards. If the holes are suspect, you can then push back on your board
supplier.
Thanks,
Robert Furrow
SMT Process Engineer
978-960-3224
[log in to unmask]
> ----------
> From: Werner Engelmaier[SMTP:[log in to unmask]]
> Reply To: TechNet E-Mail Forum.;[log in to unmask]
> Sent: Wednesday, August 18, 1999 9:03 AM
> To: [log in to unmask]
> Subject: Re: [TN] Via Fill...(I know ya'll are sick of this! BUT...)
>
> Hi Paul, Steve, and all others,
> Paul is right; when you have less then good quality drilling or poor/thin
> plating, PTV barrel failure can occur at less severe use conditions. For
> good
> quality PTVs higher loads are necessary to fatigue a PTV barrel in a time
> frame that matters. Any stress concentration, as results from a partial
> solder fill will add to the load near the fill/no-fill interface or a
> localized thin plating due to glass fiber rip-out during drilling, will
> shorten the time to failure for a given loading condition.
> From a purely a solder joint reliability issue a 75% (or even 50% fill)
> makes
> liitle practical difference. That is what has driven the recent attempts
> to
> change 610; but one has to look at the whole picture.
> For PTV barrel reliability 75% fill is a little bit better than 50% fill
> because 50% fill would typically end near the barrel center where the
> highest
> loads occur in an unfilled PTV, but given a partial fill the location of
> maximum load will move towards the unfilled section.
> Lands at layers 1, 2, N-1 and N typically see higher loading because they
> experience more land rotation during soldering operations. In my
> experience I
> have not seen the significant quality differences that Paul mentions at
> these
> locations.
>
> Werner Engelmaier
> Engelmaier Associates, L.C.
> Electronic Packaging, Interconnection and Reliability Consulting
> 7 Jasmine Run
> Ormond Beach, FL 32174 USA
> Phone: 904-437-8747, Fax: 904-437-8737
> E-mail: [log in to unmask], Website: www.engelmaier.com
>
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