blog: Two Year Component Date Questions

QUESTION:

We are a contract manufacturer. We currently have a quality mandate to purchase components that have a manufacturing date code within 2 years. This is due to solderability issues we have had in the past. This mandate causes many problems with our purchasing components especially from large distribution channels.

Are there any industry standards or best practices concerning this issue? Is this shelf life issue as prevalent as it once was?

M.M. 

Answers:

I have run into this requirement for a couple of customers over the years, however I have not seen it for a while. Applicability really depends on the component, packaging and handling; both by your organization and anyone else you may have handled the product prior to receipt. Meaning this should be looked at case by case or as quality issues arise in the process.

I am unaware of any standards that apply specifically to the shelf life of components.

Tod Cummins

Director of Corporate Quality Assurance

Delta Group Electronics Inc.

Tod has been working in the Aerospace Electronics Industry for 25 years, beginning with 4+ years working for PCB fabricator ending as the Quality Manager and 20 years with Delta Group Electronics Inc. an AS9100 registered electronics contract manufacture. Currently position is Director of Corporate Quality Assurance.

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Date codes, dates of expiration, used by dates, shelf live, what do they all mean?

J-STD-002 and J-STD-003 discuss plating requirements on boards and component. They also discuss storage and packaging materials. IPC-6012 also discusses the various coatings and thickness for printed circuit boards. So there is plenty of information in the market place on how to define what you want, how to do the testing to make sure the materials do in fact meet the requirements and how to create your documents with the appropriate information so you get what you ordered.

If there were solderability issues in the past, how were the components handled, what was the environment in which they stored, what was the packaging in which they were stored, what was the initial plating on the components, were the components checked initially to make sure they were solderable, was the plating thickness within the requirements of your specifications. All these issues have to be addressed, reviewed and considered in the causal effect determination program.

Secondly, the process: was the flux changed, was the soldering process changed, was the thermal profiled changed, was the tooling and equipment changed, were the operators changed. Again another investigation into what is different? This creates another causal investigation?

Third the business, why do you buy components and materials to have them hang around for two years? This is not good supply chain practices, this is not Just in Time Manufacturing. If the issue is small volume manufacturing and to get the appropriate price breaks in purchasing, larger quantities will have to be purchased, then many operational issues have to be considered within the manufacturing site to justify the lower cost of buying the products. Material cost is one thing, but handling and storing them incorrectly for periods of time may be much more costly and have more financial impact on the solderability and reliability of your product than the initial inexpensive material cost.

Shelf live issues are related to deterioration of the product. Is it still a problem, my answer is yes and no, as it depends upon how the material is acquired, received, stored, and used as previously mentioned. Everything must work together to make it happen.

Answers:

 I do not know of a written standard except for moisture sensitive devices. It seems that many companies have adopted the 2-year rule as a norm. The main issue is component solderability. With time, SMD terminations will oxidize affecting wetting, solder joint appearance and component performance.

I have worked with several contract manufacturers and OEM's that perform a series of solderability tests to extend shelf life or to accept components passed the 2 year mark.

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