Criteria evaluation for cleanliness testing phase 0

The Boeing Company (Boeing) contracted with Lawrence Livermore National Laboratory (LLNL) to develop criteria for evaluating the efficacy of its parts cleaning processes. In particular, LLNL and Boeing are attempting to identify levels of contamination that lead to parts failures. Sufficient contamination to cause impairment of anodizing, alodining, painting, or welding operations is considered a part failure. In the Phase 0 part of the project that was recently completed, preliminary analyses of aluminum substrates were performed as a first step in determining suitable cleanliness criteria for actual Boeing parts made from this material. A wide spread of contamination levels was specified for the Phase 0 test coupons, in the hopes of finding a range in which an appropriate cleanliness specification might lie. It was planned that, based on the results of the Phase 0 testing, further more detailed analyses (Phase 1 testing) would be performed in order to more accurately identify the most appropriate criteria. For the Phase 0 testing, Boeing supplied LLNL with 3 x 6 and 3 x 10 aluminum test panels which LLNL contaminated with measured amounts of typical hydrocarbon substances encountered in Boeing s fabrication operations. The panels were then subjected by Boeing to normal cleaning procedures, after which they went through one of the following sets of operations: l anodizing and primer painting . alodining (chromating) and primer painting l welding The coatings or welds were then examined by both Boeing and LLNL to determine whether any of the operations were impaired, and whether there was a correlation between contamination level and damage to the parts. The experimental approach and results are described in detail