Implications of Replacing 1,1,1 Trichloroethane with N-propyl Bromide for Vapor Solvent Removal of RMA Flux From Printed Wiring Boards

摘要

After RMA flux-assisted hand and wave soldering of components onto printed wiring boards (PWBs), the flux must be removed in order to meet low ionic contamination requirements. Lockheed-Martin, and much of the astronautics and aeronautics industries, have traditionally used 1,1,1 trichloroethane to remove RMA flux after soldering. However, this ozone depleting compound (ODC) was eliminated from use on all work at Lockheed-Martin by December of 1997. This paper discusses the extensive research that was done in choosing a non-ODC vapor cleaning solvent among other possible cleaning methods, and also the choice of N-propyl bromide (nPB) among other possible vapor cleaning solvents. Finally, the problems and benefits of cleaning and stripping with nPB since we made the switch-out in October of 1997 is discussed. This presentation will be useful to others in the electronics industry who are considering alternatives to an ODC solvent for PWB cleaning and stripping.