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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


over-shelf-life PCB

andy

#20429

over-shelf-life PCB | 19 June, 2002

we have a big inventory of over-shelf-life PCB, most of them are stored over 2 years. Could we ensure all these over 2 years PCB will not cause significant quality issue after assembly? and where could I find the related specification?

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#20430

over-shelf-life PCB | 19 June, 2002

If you can assemble flawless products with these boards, do not be concerned about post-assembly quality issues.

There is no current related specification in the US. Although, there may be some old military specifications that apply, but you would know about them, since they would be defined in your contract.

There real issue with boards like this is maintaining solderability. Solderability is a function of: * Design. * Fabrication methods and materials. * Packaging for storage. * Storage conditions.

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andy

#20433

over-shelf-life PCB | 20 June, 2002

thanks, but I also encounter the solderability problem. because these boards are HASL or Ni/Au finish, and we print the solder paste and reflow, the result shows the some non-wetting area. and the reliability test also proves to be bad. so the critical thing we faced is how can we deal with them, can we apply some methods to rework these board and then go into normal production. some thing we will do: 1.inspection the IMC 2.weight the moisture 3.solderability test

I would appreciate your suggestion.

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#20439

over-shelf-life PCB | 20 June, 2002

Either you need a stronger flux or the solderable surfaces need to be reconditioned. Most board fabricators don't do reconditioning. Search the fine SMTnet Archives for discussion on ROSA. EMPF is one place that does ROSA on a contract basis.

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