Jean-Paul:  I agree that Mr. Hobbs does a good job of presenting the HASS / HAST
philosophy in his book.  I was just splitting hairs (oh that some remained) on the
practicality issue.  Dave Fish

Jean-Paul Clech wrote:

> David,
> I guess that , because of the nature of the business we are in, most of the
> technology-oriented books are out-of-date as soon as or before they are
> published.
>
> I am glad to hear that there is a new vibration book by D. Steinberg in the
> works.
> The old vibration equations appeared to be very conservative when compared to
> several sets of recent failure data I worked on. The underlying reason being
> that the previous empirical fatigue correlations were developed for specific
> assemblies and have not been validated for new assembly technologies (like
> BGAs, CSPs). The MANTECH program also had to modify the Steinberg vibration
> model for LCCC assemblies.
> I'll be looking forward to the new ones because vibration  is an issue for
> large components in applications where vibration is an on-going part of life.
>
> As far as ESS is concerned, there has been some excellent papers (and
> dedicated technical sessions) on that particular topic at Nepcon West during
> the last few years, incl. 2000. However, ESS/HAST is product specific and has
> to be tailored to every particular design and objectives. I thought that
> Gregg Hobbs did a pretty good job of presenting the HASS / HAST philosophy in
> his boook. Even found some useful data on the effect of ramp rates in there.
>
> With best regards,
> Jean-Paul
> ____________________________________________________
> Jean-Paul Clech
> EPSI Inc., P. O. Box 1522, Montclair, NJ 07042, USA
> SMT / BGA / Flip-Chip / CSP Assembly Reliability Specialists
> tel: +1 (973)746-3796, fax: +1 (973)655-0815
> home page:  <A HREF="http://members.aol.com/Epsiinc1/index.html">epsi</A>
> URL:
> http://members.aol.com/Epsiinc1/index.html
>
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