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28 The PCB Magazine • September 2016 meet Class 1 requirements would meet Class 2 and Class 3. • Quality Conformance: Class 3 prod- ucts have more rigorous requirements for qual- ity conformance measures. In general, Class 3 products are required to use a more discrimi- nating sampling plan and many of the confor- mance tests need to be performed at a higher frequency than Class 2 or Class 1. It was mentioned that MIL-PRF-31032 specifications are very close to IPC 6013 Class 3. While this is largely true, there are some dif- ferences worth noting. The following are a few examples: • MIL-PRF-31032 specifically states that tin plating is not allowed; IPC 6013 class 3 allows tin plating • MIL-PRF-31032 sets a different conductor thickness reduction allowance for electrodepos- ited copper (ED) versus rolled annealed copper (RA). IPC 6013 does not distinguish between the two copper types for thickness requirements • MIL-PRF-31032 sets the requirements for minimum conductor space and width reduc- tions as "As Specified" whereas IPC 6013 states a specific percentage (20%) Many believe that, from a true performance standpoint, there is little or no difference be- tween products built to IPC 6013 Class 3 versus MIL-PRF-31032. Much of the criteria and word- ing is the same and in fact MIL-PRF-31032 will refer to IPC 6013 for many of its feature require- ments. Most of the differences that do exist are inconsequential to product performance. PCB Dave Becker is vice president of sales and marketing at All Flex Flexible Circuits LLC. To read past columns by Becker or to contact him, click here. FLEX CIRCUIT SPECIFICATIONS FOR COMMERCIAL AND MILITARY APPLICATIONS In a recent I-Connect007 sur- vey on the military/defense and aerospace markets, respondents were asked about their great- est challenges regarding PCB design, fabrication, and assem- bly; their customers' demands; whether lead-free components are still an issue; and compliance challenges. Their biggest issues include reliability, outdated drawing/specifications, component obsolescence, complicated paperwork and documentation, coun- terfeit components, quality, and compliance to stan- dards. According to our survey, most companies no lon- ger have any issues on lead-free components, which was the case as the industry transitioned to RoHS compliance. While the supply chain consists of lead- free components now, companies have figured out what to do to work with them. However, the only problem still is cost. Some issues, on the other hand, include control- ling phosphate levels in lead plat- ing, reflow temperature compat- ibility, and connection reliability. The International Traffic in Arms Regulations (ITAR) is a set of United States Government regulations on the export and import of defense-related ar- ticles, related technical data and defense services. EMS providers creating electronics subassemblies for military/de- fense applications are required to register with the Directorate of Defense Trade Controls (DDTC) in or- der to be ITAR compliant. Respondents indicated that ongoing compliance is the biggest issue when it comes to ITAR, especially with global enterprises. According to the respondents, the classifications are not based on an understanding of the technol- ogy, but rather, they are political, and as such subject to intense lobbying efforts. They are also changing frequently, which leaves companies scrambling to re- classify parts of their designs on the fly. I-Connect007 Survey: A Look at the Mil/Aero Industry

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