Many components won't need special storage requirements. However, plastic 
SMDs are susceptible to cracking or "popcorning" during reflow due to 
moisture absorbed through humidity in the factory or during shipping (if 
not properly sealed).

Typically the component supplier will put a label indicating shelf life 
and handling requirements (indicated by a number, 1-6, depending 
on the susceptibility to moisture).

I would advise reviewing IPC-SM-786A, "Procedures for Characterizing and 
Handling of Moisture/Reflow Sensitive ICs."

It's available from IPC, 847-509-9700, ext. 316. Price: $15 for IPC 
members, 30 for nonmembers.

Mike Buetow
IPC Technical Staff
2215 Sanders Road
Northbrook, IL 60062
P: 847-509-9700, ext. 335
F: 847-509-9798
[log in to unmask]



On Wed, 21 Aug 1996, Kenny Bloomquist wrote:

> On August 16th I wrote the following question.  Unfortunately I did not
> receive any responses.  I am sending this again in hopes that the people
> with good comments are still out there in TechNet land.
> 
> This is a request for input on recommended shelf life for SMT components.
> Our company uses small quantities of SMT components but we often purchase
> reels of components which will last for quite some time.  We currently do an
> incoming solderability test and if the components pass we establish a shelf
> based on the manufacturing date of the component.  What I am asking for is
> any advise on what a reasonable shelf life should be for SMT components
> stored in a building with 30 to 60 percent humidity and 72 plus or minus 5
> degrees Fahrenheit.  The components are placed in ESD bags with a piece of
> 3M OAP paper.
> 
> Thanks in advance for any and all comments.
> 
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