Ask the Experts
December 13, 2016
Two Year Component Date Code Mandate
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?
Expert Panel Responses
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.
Director of Corporate Quality Assurance
Delta Group Electronics Inc.
Tod has been working in the Aerospace Electronics Industry for 20+ years, beginning with 4 years working for PCB fabricator ending as the Quality Manager and 16 years with Delta Group Electronics Inc. an AS9100 registered electronics contract manufacture. Currently position is Director of Corporate Quality Assurance.
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.
Vice President, Technical Director
At EPTAC Corporation, Mr. Lambert oversees content of course offerings, IPC Certification programs and provides customers with expert consultation in electronics manufacturing, including RoHS/WEEE and lead free issues. Leo is also the IPC General Chairman for the Assembly/Joining Process Committee.
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.
Senior Manufacturing Engineer
Edithel is a chemical engineer with 20 year experience in manufacturing & process development for electronic contract manufacturers in US as well as some major OEM's. Involved in SMT, Reflow, Wave and other assembly operations entailing conformal coating and robotics.
At IEC Electronics, also an electronics services manufacturer (CM), we too are routinely confronted with quality mandates on components purchased depending on EOL, OBS, Counterfeit as well as solderability mitigation industry requirements. First, the best suggestion I have is to ask the best company I know who provides component preparation services(Corfin resident expert Don Tyler ) to the defense, aerospace, medical, telecommunications, transportation, industrial, and other high reliability industries. Corfin is recognized for pioneering "Robotic Hot Solder Dip" for the delivery of product that is <2 years since manufacture and packaged per GEIA-STD-0003.
Second, require that parts must pass solderability testing if you choose to perform. Third, then take what you get and perform solderability tests on older parts at incoming inspection and reject failures accordingly.
Finally, if customer suggests alternate to "Robotic Hot Solder Dip" be aware of the stripper chemical possibly utilized to remove plating's as it gets trapped in the lead body interface and will corrode over time, hence subsequent electroplating cannot be performed after manufacture. With these mandates, especially solderability, the following conditions address the mitigation of the degradation of solderability over time, but they are not likely conditions you can mandate on the big distribution guys:
- "Robotic Hot Solder Dipped" parts don't have the porosity of plated parts. This is recognized by MIL-PRF-38534 and -38535 by requiring 300 uin of tin-lead plate or as little as 60 uin of hot solder dipped tin-lead to accomplish the same base metal protection. Most commercial parts have tin plating thinner than 200 uin.
- GEIA-STD-0003 Long Term Storage of Electronic Devices provides packaging parameters to protect finishes on parts for storage of greater than 12 months. Key elements are a heavier thickness of moisture barrier bag, double heat seal, nitrogen purge, and extra desiccant.
- The obsolete MIL-STD-2000 would allow for a reset of the 2-year storage period if a sample passed a solderability test.
VP of Advanced Technical Operations
Mark has over 25 years' experience in electronics fabrication, quality and reliability while working for IEC Electronics, GE, Motorola, ORS, etc. He has most recently established IEC Electronics Analysis and Testing Laboratories (IATL), LLC in Albuquerque, NM for electronics and material analysis testing in the military, medical, and industrial industries. His area of expertise includes PCB, PCBA, components, analytical and electrical analysis techniques.
There are no industry standards that I know of that will limit your parts usage within a specific time frame other than expiration date where applicable. However, I do understand the need of using newer components to avoid process issues.
Should you have to use older components, a screening and testing for oxidation, baking, tinning can solve some of your supply chain issues.
Engineering and Operations Management
Georgian Simion is an independent consultant with 20+ years in electronics manufacturing engineering and operations.
Contact me at email@example.com.