LLNL and TRW extend benchmark environmental stress testing for two alternative printed board cleaners

摘要

TRW Corporation and LLNL jointly conducted a testing program to evaluate the effectiveness of non-CFC defluxing chemistries on printed boards designed for high reliability military and aerospace applications. TRW assessed existing data for alternative chemistries, selected candidates for further testing, implemented the cleaning processes, and performed ionic conductivity testing on the spent solvents. LLNL designed and fabricated special circuit boards with interdigitated comb patterns to allow insulation resistance (IR) measurements under selected soldered components. LLNL designed the test and measurement setup and conducted accelerated environmental stress testing of flux residues for 28 days following cleaning. Statistical analyses of the IR measurements were correlated with visual observations and spectroscopic (FTIR) measurements. Performance of the alternative chemistries was compared with that of a standard CFC cleaning agent also included in the test program. The program was designed to follow the same environmental stress and electrical measurement requirements as the IPC/DOD/EPA Ad Hoc Solvent Working Group's benchmark 7-day test plan, but with certain minor modifications and extension to 28 days.