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Wed, 17 Jul 2002 11:03:09 EDT |
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Hi Dave,
The problem in recent years has been that people use HASS and HALT [no real
fixed definition for either] without any thought or understanding what the
results actually mean for the product. In most cases, the "HIGHLY
ACCELERATED" is no such thing; producing failures quickly is not necessarily,
and in most cases assuratly not, accelerating actual product damage
mechanisms.
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com
In a message dated 07/16/2002 17:52:00, [log in to unmask] writes:
>Hi Werner! Terry is describing a HASS (highly accelerated stress screen) or
>a HALT (highly accelerated life test) type of chamber. We have six of the
>HASS chambers which are used to improve printed wiring assembly design
>robustness (we track what fails, determine if that failure mode/mechanism
>is valid for the use environment and make any appropriate design
>improvements). These chambers can indeed provide temperature ramp rates of
>5-50C per minute (they use LN2 boost) - the ultimate in thermal shock
>recipes. I think you raised the most important questions - what is the
>relationship of the failure modes/mechanisms induced by the HALT chamber
>and the failure mechanisms the printed wiring assembly undergoes in its
>use environment? Pretty tough question.
>Dave Hillman
>Rockwell Collins
>[log in to unmask]
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