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ELECTRONIC COMPONENT COOLING ALTERNATIVES: COMPRESSED AIR & LIQUID NITROGEN
Citation:
Schmitt, S. AND R. Olfenbuttel. ELECTRONIC COMPONENT COOLING ALTERNATIVES: COMPRESSED AIR & LIQUID NITROGEN. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-94/170.
Description:
The goal of this study was to evaluate tools used to troubleshoot circuit boards with known or suspected thermally intermittent components. ailure modes for thermally intermittent components are typically mechanical defects, such as cracks in solder paths or joints, or broken bonds, such as interconnections inside integrated circuit packages or capacitors. pray cans of refrigerants (R-12 [CFC-12] and R-22 [HCFC-22]), which are commonly used in electronics manufacturing and repair businesses for this purpose, served as the benchmark for the evaluation. romising alternative technology that was evaluated in this study is a compressed-air tool that provides a continuous stream of cold air that can be directed toward specific components. nother alternative technology that was considered is a Dewar flask that dispenses cold nitrogen gas as the cooling agent. ritical parameters were measured for each cooling method to provide a basis for comparison of compressed air and liquid nitrogen with spray cans of refrigerant. hese parameters are accuracy, electrostatic discharge risk, cooling capability, technician safety, pollution prevention potential, and economic viability. ewark Air Force Base, in Ohio, was the site for evaluating compressed-air and liquid nitrogen technologies. lectronic circuit boards from a variety of Air Force Systems are tested and repaired on a daily basis. ercentage of these circuit boards demonstrate thermally intermittent failure modes and were used for comparison testing.