Getting the Lead Out of Hot Air Soldering

摘要

As lead-free legislation looms, a new form of eutectic tin-copper has been developed as a wave solder replacement, eliminating many of the problems associated with the tin-copper alloy. The electronics industry is approaching the end of the era of tin-lead solder. Good, old 63/37 eutectic tin-lead solder has been a mainstay of electronic fabrication since its earliest days, but modern concerns over lead exposure in our environment, especially ground water contamination, have forced the industry to seek lead-free alternatives. This hasn't been easy. Tin-lead solder has many advantages: a melting point (183℃) that's high enough to remain solid in normal applications but still low enough to not seriously damage the printed circuit board and its components, a fairly long shelf life if stored properly, and if kept free of impurities, capable of a smooth, free wicking application with minimal flux. That's a lot for a lead-free solder to replace.