Hi Dave,

Not sure if this helps much or not, but I found this:

http://www.circuitinsight.com/pdf/final_finish_specifications_review_ipc_plating_ipc.pdf


and I was able find this 4552 which is an old rev because I think it's at
Rev A now, but if you look starting at page 19 where it talks about aging,
there's a pretty good bit of discussion there that's interesting...

http://noyancircuits.ir/wp-content/uploads/2018/05/IPC-4552.pdf

Not exactly sure why they wanted to limit it to 6-months based on the way
it's talked about in that section...

Steve



On Tue, Aug 13, 2019 at 12:46 PM Dave Schaefer <[log in to unmask]> wrote:

> Many older postings on this forum and PCB vendor publications regarding
> ENIG plating suggest this finish has a very long shelf life, in excess of
> 12 months. However, the somewhat dated IPC-4552 specification I have
> suggests the shelf life be limited to 6 months.
>
> Can anyone elaborate on what the IPC-4552 recommendations are based upon?
> Also, what types of failures would one expect to see with PCBs exceeding
> the recommended shelf life?
>


-- 
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133

-- 



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