Can lead-free solder joints be completed using a soldering iron and tip that were previously used for tin/lead soldering?  

Contamination of one type of solder with another can have consequences on solder joint reliability. As many facilities transition to lead-free soldering, there will probably be a phase where both tin/lead and lead-free solders will be used at the same time. This will require that material controls are in place to prevent cross contamination of the solders.
Some facilities are considering, or implementing, the complete physical separation of one process (tin/lead) from the other (lead-free). This includes the hand soldering operation and the hand soldering equipment (irons, tips, etc.).

This paper will review an alternative to physical separation: the ‘rinse’ method of eliminating lead from a soldering iron tip. Results of laboratory analysis of solder samples from tin/lead soldering stations used for soldering lead-free solder joints will be revealed. The results will show whether it is possible to switch solder materials (by using the ‘rinse’ method) on the same soldering iron and tip without a risk of lead contamination of the solder joint.

This article originally appeared in Global SMT & Packaging magazine 6.1 - Jan 2006.

Download the full article (free) in PDF format.

Ray Cirimele (rcirimele@solder.net) is operations manager of Business Electronics Soldering Technologies, Inc. Ray is an international speaker in electronics manufacturing and has over twenty years experience in the industry performing electronics maintenance, manufacturing, PCB fabrication, rework and repair, sales and training. Ray has previously worked for the Department of Defense (DOD), Northrop/Grumman, U.S. Robotics/3Com, Electronics Manufacturing Productivity Facility (EMPF), Enthone-OMI, and Diversified Systems. Ray is an active member of the IPC and has received several awards for his involvement on IPC training videos as technical content advisor.