Conductor surfaces on printed-circuit boards (PCBs) plated with tin-lead alloy and later fused (reflown or melted) can display a variety of topographical features. Surfaces should be bright and shiny as it is difficult to disposition PCBs with unusual grainy features during subjective quality inspection. This report provides workmanship standards of undesirable surface finishes that have been compared against destructive solderability and metallographic tests. Tin-lead platings with a large grain size or composition markedly different from the eutectic are unsuitable for fusing. Attempts to improve a poor surface finish by multiple fusing operations are totally unacceptable.
Examination of fused tin-lead plated printed-circuit boards supporting various surface features
Pruefung von geschmolzenen Zinn-Blei-Plattierungen auf Leiterplatten bei verschiedenen Oberflaecheneigenschaften
1989
30 Seiten, 42 Bilder, 2 Tabellen, 5 Quellen
Report
English
POLYIMIDE PRINTED CIRCUIT BOARDS
SAE Technical Papers | 1979
Optical links for printed circuit boards
IEEE | 2003
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