Lead-Free Rework Experiences Using SAC

ABSTRACT As companies transition over to lead-free assembly a certain amount of hand-soldering and rework will be performed. An article from Tech Search International last year did state that in Asia where lead-free soldering is much more common, hand-soldering was more of a production problem than lead-free SMT or wave soldering or other soldering processes. In fact most user problem calls and requests for training these days are related to lead-free hand-soldering and rework. In many cases the assemblers are using materials from various solder suppliers with similar issues occurring in all cases. Often the problems are more than just material issues. Switching to lead-free without proper preparation is not recommended. Although this seems easily understood some assemblers have attempted to transition without adequate training; resulting in line stoppages occurring only a few hours into lead-free hand-soldering. Operator complaints, loss of reliability and poor joint quality were experienced. This could be a production engineer’s nightmare but it need not be this way if the basic concepts of hand-soldering are revisited, some experience gained prior to the transition and adequate training of operators is performed before and after the switchover. This paper is a compilation of questions often asked by assemblers in reference to hand-soldering with lead-free. These questions are in fact some of the issues addressed during lead-free hand-soldering on-site audits or training at assemblers using lead-free solders at their facilities. It offers practical answers as to enable the reliable implementation of lead-free.