Shelf life of OSP boards is dependant upon several variables:
*  OSP formulation  (supplier)
*  Assembly process variables such as flux type, flux application 
method, number of thermal excursions the product sees, assembly 
atmosphere (air vs nitrogen), etc.....
*  Packaging and storage conditions

Most suppliers of the newer, substituted benzimidazole compounds 
advertise up to 12 months using "typical" PCB packaging procedures. 


Some actual experience...

One customer that uses water soluble (organic acid), mixed technology, 
open air assembly has successfully processed boards that literally sat 
for one year on a shelf in a "factory" environment  (uncontrolled 
atmosphere).

Another customer with mixed technology, open air, no-clean assembly 
processing was successful after 6 months storage in a similar 
environment (he stopped testing after 6 months).


David Boggs
Merix Corporation
email:  [log in to unmask]




[log in to unmask] Wrote:
| 
| Date : 15/5/96 18:11
| Msg From: ATUL RASTOGI
| The shelf life of OSP boards is 6 months in vacuum sealed 
| packs.You
| can store these boards from a RH ranging from 30% to 70% 
| without any
| deterioration in the shelf life as long as vacuum seal is 
| intact
| 
| Atul Rastogi
| >>>>>>>>>>>>>>>
| 
| Posted: Tue, May 14, 1996  11:25 PM                  Msg:
| BJJG-2076-4363/20
| From:   ("RFC-822": <TechNet-request(a)ipc.org>, 
| SITE:INTERNET) 
| To:     ("RFC-822": <technet(a)ipc.org>,SITE:INTERNET)
| CC:     AIL.EHTP/PCL
| Subj:   ASS: Storeage of PWB
| 
| RFC-822-Headers:
| Resent-Date: Tue, 14 May 1996 06:41:27 -0700
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| 
| What is the shelf life of Copper bare boards with OSP 
| finish.
| What is the nominal RH at which the board may be stored at.
| If it's 45% RH, what's the effect  if environment RH is 
| increased to
| 60%
| ie what effect will an increase of RH have on the PWB 
| during
| storeage?
| Thanks in advance.
| 
| 
| <<<<<<<<<<<<<<<
|