A Study of Soldering Tip Life on Lead-Free Alloys

ABSTRACT The life span of soldering tips operating with lead-free alloys has been evaluated as they show less durability than those operating with conventional tin-lead (SnPb) solder. This issue has been exacerbated by the higher temperature of lead-free (Pb-free) soldering and the higher tin (Sn) content (tin readily erodes iron (Fe) plating) and more aggressive flux in lead-free soldering. Since the implementation of the European Union's Restriction of Hazardous Substances (RoHS) directive which took effect on 1 st July 2006, many companies, especially those in Europe and North America have adopted SAC405 as the lead-free alloy of choice. Hence, in this study, SAC405 solder wire was chosen as the natural rework solder for the investigation on the durability performance of solder tips from various suppliers. One of the known concerns when working with SAC405 alloy is the higher copper (Cu) dissolution rate, which sometime causes increased defect rates; especially in multiple PTH reworks. Another concern is the relative higher price of the alloy due to the silver (Ag) content. In this paper, an alternative lead-free solder, Sn-Cu + Ni is proposed to determine the effect of alloy on solder tip life when compared with SAC405 base alloy.