Hi Suzanne! Solderability of pwbs is a function of the type and quality of
surface finish deposited. You will find a wide variation of "responses" on
the shelflife of the different surface finishes available. The more you are
willing to pay, the better the shelflife guarantee you will find. Rockwell
Collins has looked at a number of immersion tin chemistries and we found a
wide spectrum of performance (good to bad). My expectations for any pwb
surface finish is 12 months of shelflife in controlled storage conditions
(75F +/-10, 30-60%RH). I have found a number of surface finishes (immersion
tin, immersion silver, immersion gold, OSP, immersion palladium) which can
meet the 12 month shelflife - provided you partner with your pwb
fabricator.  The real key is teaming with your pwb fabricator and having
everyone understand your expectations of the surface finish. Good Luck.

Dave Hillman
Rockwell Collins
[log in to unmask]




Lupita Roberts <[log in to unmask]>@ipc.org> on 03/20/2002 10:34:07
AM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
       to Lupita Roberts <[log in to unmask]>

Sent by:    TechNet <[log in to unmask]>


To:    [log in to unmask]
cc:

Subject:    [TN] FW: shelve life of pwb's


I am wondering if anyone can help me with the shelve life of raw
PWB's. I was experiencing solderability issues and oxidation issues
with some boards. I was told by several suppliers that White Tin only
has a shelve life of 6 months and they were not warrantied beyond that
point. I have been unsuccessful in trying to find data in regards to
this issue.

Suzanne Foulkes
QC Supervisor
Inservco Inc.
LaGrange, Ohio 44050

[log in to unmask]
[log in to unmask]

---------------------------------------------------------------------------------

Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]:
SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
---------------------------------------------------------------------------------

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------