Issue link: https://iconnect007.uberflip.com/i/288471
54 SMT Magazine • April 2014 grows. These systems are being introduced to conditions that would have been considered unsuitable for electronics a short time ago, in- cluding condensing environments and dust environments. Some of the known benefits of coating include: • Reducing entrapped surface contamination to contact power or ground areas • Tin whisker mitigation Having engaged multiple conformal coat- ing manufacturers, there is a common recom- mendation for the application of conformal coating; that is that the substrate be cleaned prior to application, regardless of the type of coating to be applied. These same manufactur- ers will also admit that many of their custom- ers are coating over no-clean flux residues for a variety of reasons. The most common being: • Cost of cleaning • Throughput requirements • Incomplete removal of ionic contamination under and around low-standoff devices • Tin whisker mitigation Analyzing final working environment is cru- cial to a successful outcome and should be the first consideration in determining the appro- priate assembly process. One should determine if applying coating will: a) achieve the desired outcome b) be practical given the nature of the assembly and the assembler's capabilities. As- suming coating is appropriate the materials to be used need to be vetted. fEATurE CONFOrMal COaTiNG OvEr NO-ClEaN FlUX continues Charts 1-5.