By Courtney E. Howard
SAN DIEGO, 11 March 2008. In an afternoon session at the Military & Aerospace Electronics Forum titled, "The Effect of Lead-free Regulations on the COTS Procurement Process," Vance Anderson, an engineer with the Defense Microelectronics Activity in McClellan, Calif., discussed the impact of the European Union directive for the Reduction of Hazardous Substances (RoHS) banning the use of certain materials in electronic equipment.
Lead in found in electronics systems in various areas, including: component finishes, solder, printed wiring board finishes. Lead can also be found in components that don't always come to mind when someone says "electronics," such as connectors, lugs, cardguides, packages, lids, and so on.
"We are changing the materials we have been using for 30 or 40 years," Anderson says. This move to lead-free electronics impacts the U.S. Department of Defense in several ways. It can result in: tin whisker failures, lead-free solder challenges, repair and rework, mixed material environments, and the reduced availability of lead-bearing solder and components.
The commercial market is driving technology, but the DoD has specialized requirements. The lead-free movement has a much greater impact on the DOD, which requires reliable, repairable systems with a long service life. "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." After all, he continues, the mil-aero market has a few things that the consumer electronics segment doesn't: long-term harsh-service requirements, strict qualifications testing, and a 20-year service life.
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, he says.
