Eliminating Solvents in the Cleaning of Circuit Assemblies: A Case History

Abstract

This paper describes the work that was necessary to eliminate CFC (chlorofluorocarbon) cleaning solvents in the post‐soldering defluxing operation during assembly of printed wiring assemblies (PWA) in an off‐shore electronics manufacturing plant. The pressures—both external and internal—to utilise environmentally clean processes are becoming increasingly great in off‐shore manufacturing facilities, just as throughout the US. However, as will be shown in this paper, producers of electronic equipment must continue to ensure that a high level of product performance and reliability is not sacrificed when going to more environmentally favourable materials and processes. The study described here consisted of examining several water‐soluble flux materials, measuring ionic contamination levels of both Freon® TMS‐cleaned and water‐cleaned assemblies, and functional testing of the assembled devices at various levels of functional test severity. Materials, methods and actual physical data are presented in this paper.