Letter Re: "Industry Steps Up to Make the World A Bit Cleaner" or "Who's Responsible for the Lead-Free Mess"?


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Thank you for such a carefully articulated article. I especially appreciate the way you equally represented all the sides. I would prefer that you keep my name out of the press.

 

I work for a defense contractor, and we build a wide range of military products; from Hi-Rel space applications to commercial-like office environments. Even though we are exempt from RoHS certification, our supply chain has been significantly and permanently altered. We are gradually phasing in the lead free process where our contracts allow, not because we just like to share in the pain, but because we can no longer procure parts with tin-lead finish. The issue of cost and availability of lead bearing finishes will make our products non-competitive. We are quite concerned about long term reliability of the solder connection, and have only considered this move on products that don't have as stringent an environmental requirement. In addition, many of our customers require that we keep at least 3% lead in our solder connections, because of fears over tin-whiskers. This is forcing us to implement re-balling and re-plating processes, exposing our components to further temperature and handling stresses.

 

While we are benefiting from the many industry studies and excellent research papers that are written about processing, metallurgy, and reliability, we are still running our own internal testing to qualify these new processes.  Controlling our internal inventory, and screening new shipments is adding further to our cost concerns. The cost implications are spread out over many different projects and departments, and I feel the greatest costs are yet to come, as we begin to maintain our already deployed units.

 

As most defense contractors have become systems integrators, the risks of deploying lead free COTS (commercial off-the-shelf) assemblies in harsh environments is increasing. Where the defense industry once could rely on COTS reliability to meet the military environments, further efforts are now required to "ruggedize" these COTS assemblies, and additional qualification testing is required. All these impacts are rolling up to higher costs to the government and greater risks to mission critical systems. While some may argue that military systems are over designed and the environmental requirements are exaggerated, but our recent successes in the Gulf War are a clear indication of the necessity to maintain the higher expectations. (Who's to say that our next conflict won't be waged in the bitter cold.) Our nation's investment in new technology is not merely the latest wave in consumer features. These systems are still fully utilized more than 10 years after deployment. This makes it extremely difficult to change from the known behaviors of the tin-lead solder joint.

 

From our perspective, we definitely agree with your comments of the RoHS conversion, "a huge waste of industry resources", and "an unnecessary and wasteful transition". I share your optimism that out of this,  "our factories are cleaner and more efficient, wasting much less process chemistry.", but it is difficult to find a metal that absorbs stress and conducts as well as lead. I guess the single best by-product is that the component manufacturers will be making parts that withstand higher processing temperatures, which usually results in better field performance (stable Cte).

 

Respectfully,

 

Chief Engineer, Manufacturing

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