SMD reeled components

Jack: You should use your components promptly. Don't store 'em, only bad things will happen to them.

1 You should store all your components, not just your SMD reeled components, so they are not damaged or their solderability decreased. Check the archives for discussions on temperature and humidity levels. 2 The maximum time from the "date of manufacture" that components can be stored depends on the manufacturing processes used to fabricate the components and the handling and storage conditions the components "see" between the time of their manufacture and their end-use. � We routinely solder components over 5 years old taking no special steps. � Then again, we periodically have a tough time soldering capacitors with date codes less that 6 months old. 3 I�d guess that different companies take different approaches in specifying their date of manufacture and acceptance of that manufacture. For us, the time from when an assembly is complete and when it is released for shipment varies depending on customer requirements, shop loading, and what not. Maybe your supplier can give you direct insight. My2�

Dave F

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We have just completed a test for a leading manufacturer of SMT IC packages. There were some surprises. The carrier and cover tapes appear to be highly hygoscopic. The saturation curves for the tape and devices showed dramatic absorption at the beginning of the 30 deg. - 60% exposure period. The first hour out of the vapor barrier bag was a killer.

The good news that we found that the moisture could be driven out of the tape and devices in six to twelve hours at temperatures as low as 55 deg. C. Low temperature TVP drying of the reel tape and devices will have a very positive influence in solderability.

The study is available to anyone who asks.

Stu Leech sleech@ix.netcom.com

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