Original Date: 06/05/2006
Revision Date: / /
Best Practice : Common ODS-Free, Low Volatile Organic Compound, Topical Batch and In-Line Cleaning Processes
Rockwell Collins’ implementation of the “right-sized” in-line aqueous cleaning equipment and “new configuration” batch cleaning equipment using the “new generation” cleaning chemistry provide significant environmental stewardship, cost savings, and cleaning process opportunities. Rockwell Collins has the potential for a 50% cost reduction in its batch and in-line cleaning process.
Cleaning processes for printed circuit boards and the chemistry used to clean them were found to be environmentally offensive, expensive, and provided marginal cleaning results prior to 1996. Batch-cleaning system chemistries were often costly, ozone-depleting substances (ODS) that were difficult to chemically balance and contained materials that were harmful to humans, harsh with electronic assemblies, and provided marginally effective cleaning of ionic contamination. Significant quantities of the chemistry would evaporate when used, causing waste and increased cost. In-line cleaning chemistries consisted of harsh saponifiers or ODS solvent blends that did not effectively clean ionic contamination and used large and expensive energy-inefficient equipment.
Rockwell Collins addressed these cleaning issues by replacing the harsh saponifiers or ODS blends with a low volatile organic compound and an environmentally friendly cleaning chemistry that effectively cleans leaded and lead-free solder alloy flux residue. The introduction of new Kyzen cleaning chemistry can be used 10%-20 % by volume in deionized water and costs approximately the same as the previous ODS chemistry. After it was approved for use, the Kyzen cleaning chemistry is now being used in numerous Rockwell Collins in-line cleaning systems and applicable batch-cleaning systems and will continue to be added to new and existing cleaning systems through 2007.
Rockwell Collins also evaluated its batch and in-line cleaning equipment and processes to control chemistry concentration automatically or semiautomatically and reduce cycle time for wash, rinse, and dry. The new batch cleaning system (Aqueous Technologies Model 800) was recommended and installed. The new system provides cleaning-system control using a Kyzen Dosatron dosimeter. The new batch cleaning system reduced the clean-and- dry cycle time to 20 minutes. The cycle time for cleaning a batch of printed circuit boards was reduced by 50%.
Rockwell Collin also worked with its equipment supplier Austin American Technology to design and develop an in- line cleaning system. A new 12'x5'x5' cleaning system was developed that provides chemistry control and chemistry consumption that is half as much as the old in-line system. The new in-line cleaning system reduced the clean-and- dry cycle time from 13 minutes to 4 minutes. The smaller, “right-sized” in-line cleaning system allows Rockwell Collins to install the equipment closer to process and assembly operations. The smaller system used with the new cleaning chemistry has extended the life of the system’s wash sump chemistry solution.
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