My experience was steam age and solderability test components and if they
pass then to store in a drybox for up to 2 years.  After 2 years repeat
steam age and solderability and store for another 2 years.  When things
didn't pass steam age and solderability we determined the extent of the
failure and considered our needs and the current performance of the
material.  Perhaps we used it, perhaps not. C of C's are worthless as far
as I am concerned when it comes to solderability.  They were typically a
xeroxed scrap of paper that was basically useless.  All parts that failed
were supplied with a C of C. In the case of a few failed components we
found out that they were at least 7 years old and stocked by a distr'r for
that length of time.
There is no replacement for testing the components.

Denis Meloche
Heraeus Cermalloy

At 06:41 AM 8/20/97 PDT, you wrote:
>Second Posting as I am not sure the first made it.
>
>Hi everyone!!
>
>I need some help.
>
>In our company, a debate rages about the appropriate date code limitation
>to use to assure solderability of SMT components in a no-clean process.
>The engineering side of the house (that's me) recommends that in light of
>the fact we aren't equipped to do solderability testing on all materials,
>we opt for a six month shelf life as a target and dig in our heels at 12
>months. The "enemy" (purchasing) says that their vendors (distribution)
>claims that two years is an industry standard and that they cannot get
>reliable supplies if we tell our vendors we will not accept anything
>older than 12 months.
>
>For those of you working in no clean processes, or product being built to
>IPC Class III requirements, would you share with us your experiences and
>requirements with respect to component date codes?? I'd like to know your
>date code requirements on your vendors, does it cost you extra money or
>planning time, what type of products do you make, and what IPC Class
>requirements do you use?
>
>By the way, I have a copy of ANSI/J-STD-002 which was helpful, but a bit
>vague.
>
>Thanks
>
>Regards
>
>Sherman Banks
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>408/481-6047
>******************************************************
>
>