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Lead-free issues continue to plague mil-aero market, says DMEA engineer

By Courtney E. Howard

SAN DIEGO—Vance Anderson, an engineer with the Defense Microelectronics Activity in Sacramento, Calif., discussed the influence of the European Union directive for the Reduction of Hazardous Substances (RoHS) banning the use of certain materials in electronic equipment last month at the Military & Aerospace Electronics Forum in San Diego.

“Lead is found in electronics systems in various areas, including component finishes, solder, printed wiring board finishes,” Anderson told MAEF attendees in his presentation, “The Effect of Lead-free Regulations on the COTS Procurement Process.”

Lead can also be found in components that do not always come to mind when someone says “electronics,” such as connectors, lugs, cardguides, packages, and lids.

The lead-free movement has a greater impact on the U.S. Department of Defense (DOD) than the commercial market. The DOD requires reliable, repairable systems with a long service life; yet, the move to lead-free electronics can result in tin whisker failures, lead-free solder challenges, mixed material environments, and the reduced availability of lead-bearing solder and components.

“Those in the commercial market know what their market is and they are meeting their market’s requirements; a problem arises when we try to apply that same technology in military mission-critical environments,” Anderson says. After all, he continues, the mil-aero market has a few things that the consumer electronics segment do not: long-term harsh-service requirements, strict qualifications testing, and a 20-year service life. “We are changing the materials we have been using for 30 or 40 years.”

Many DoD programs will not go lead-free because of uncertainties and the risks associated with the current science and materials. “There are failures, but we’re not always hearing about it; most of the reporting is coming from government bodies. But believe me,” Anderson says, “it is hitting all the major primes right now, very hard.” The automotive, medical, and telecommunications markets are not immune, and have also experienced the same failures. Such failures are common, but not often revealed, perhaps due to stockholder pressures.

Government defense agencies and the defense industry have the same problem, Anderson acknowledges. “We are all in this together. A comprehensive lead-free strategy is underway.” The LEAP Working Group (the combined efforts of GEIA, AIA, AMC, and the U.S. government), U.S. DOD, and the GEIA and IEC standards bodies are all working together, notes Anderson.

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