Hi Phil - the solderability of a pwb is typically accountable for 12 months as tested per the IPC-JSTD-003 specification. After 12 months, you are own your own - some finishes will last longer, some will not and it all depends on the initial quality of the applied surface finish and the type of longer term storage experienced. Having boards that were stored for 24 months means that the solderability may not be acceptable. Dave Hillman Rockwell Collins [log in to unmask] Phil Bavaro <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 06/20/2011 12:12 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to [log in to unmask] To <[log in to unmask]> cc Subject [TN] Using PWBs instead of test coupons to meet IPC-6012 Class 3 I recently came across a situation where PWBs were used in lieu of test coupons to meet a contractual 3rd party micro-section test requirement for IPC-6012 Class 3 hardware. This decision was made after having the PWBs stored in the stockroom for two years. I was asked to get involved when the PWB "coupon" failed for Solderability testing by the 3rd party test house. I checked and the original PWB micro-section report from the fabricator indicated that the test coupons all passed at the time of manufacture. So I am left wondering about the requirement that is intended by 6012 to use test coupons. I would have thought at the very least, the PTH hole locations of PWB which would correspond to the test coupon sections would have to have been identified and approved. I can rationalize why the stored board would not meet Solderability requirements after two years in a stockroom, but I cannot get past the requirement to use actual test coupons for acceptance testing. Am I missing something or do we have a choice whether to test the coupons vs the actual PWB? ------------------------------------------------------------------------------ This message and any attachments are solely for the use of the addressee and may contain L-3 proprietary information that may also be defined as USG export controlled technical data. If you are not the intended recipient, any disclosure, use or distribution of its content is prohibited. Please notify the sender by reply e-mail and immediately delete this message and any attachments. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------