TESTING AND QUALIFICATION OF HFE/CO-SOLVENT CLEANING AGENTS IN VAPOR DECREASING APPLICATIONS
Author: Elizabeth A. Bivins Company: Petroferm Inc. Date Published: 9/10/1996
Surface Mount International
Abstract: There is no satisfactory replacement for vapor decreasing in many electronics cleaning tasks. This paper describes anew, environmentally friendly co-solvent/fluorocarbon vapor decreasing process that can permanently replace CFC-1 13, HCFC-141b and 1,1,1-trichloroethane in a wide variety of cleaning applications. Co-solvent cleaning is functionally indistinguishable from vapor decreasing as it is normally practiced. Importantly, this new process operates very satisfactorily in unmodified, modern vapor decreasing equipment, or in slightly modified older but well-maintained equipment. This alternative may offer the possibility of an eleventh-hour rescue for many organizations which delayed finding or couldn’t afford the equipment necessary to use other alternatives to ozone-depleting solvents. It also is attractive for those whose alternative has not fully met their expectations, or whose circumstances and requirements have changed. From the equipment operator’s perspective, the co-solvent process is run identically to a conventional vapor decreasing process in which the parts are immersed in the boil sump. The cleaning tests reported here were performed side-by-side in essentially identical equipment using the HFE/co-solvent system in one machine and HCFC-14 lb. in a second one. The two processes performed equivalently. HFE/co-solvent results to date can be summarized as follows: The HFE/co-solvent process has been implemented in completely unmodified, conventional vapor decreasing equipment, where it operates fully satisfactorily. Routine production parts were cleaned as well in the test process as with HCFC-141b. No compatibility problems were observed. n Cycle times were approximately equivalent to those used in production with HCFC- 141b. Solvent emissions were significantly reduced compared to those with HCFC-141 b; initial data indicate that the process will offer attractive economics. Cleaning costs for the new process were found to be comparable to those for HCFC-141b.