System of compatible products for assured performance in PWB assembly The presentation discusses the importance of process compatibility related to the assembly of PWB's. The performance of the assembly process is dependent upon the materials used for component attachment e.g. solder paste, drip adhesive, wave flux and tempoary solder masks. Also on surface coatings present on the PWB substrate e.g.solder mask, or pad and through hole coatings such as hot-air leveled solder, gold and organic solderability preservatives. The objective of the PWB assmbler is to maintain the throughput and first pass yields on the soldering line. Poor wetting of the PWB through holes and surface mount pads, high ionic, bridging, solder balling, solder webbing, staining and excessive or unsightly flux residues can significantly impact on the cost and efficiency of the soldering process, Compatibility of PWB coatings with the soldering materials can minimize or eliminate defects. The importance of various solderable coatings (including organic solderability preservatives), solder mask, flux and paste is presented and discussed highlighting their impact on assembly quality and reliability.
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