NBI Newsletter 10/2005:
Going "Green" - NBI Developing Lead-Free Process
NBI is developing a lead-free soldering process that conforms to IPC-A-610 Revision D.
In March of this year, NBI began a feasibility study for developing a lead-free
soldering process for manufacturing circuit boards. NBI began by reviewing the available
research material, going to trade shows, talking with other contract manufacturers, and by
polling customers to judge their level of interest. Although none of NBI's customers
expressed a strong interest in going "lead-free" at that time, NBI continued
research and began an experimentation project.
By the middle of May, NBI engineers were ready to begin hands-on experiments to find
out if the published problems with running a lead-free process would apply to NBI as well.
A set of relatively simple lead-free boards was procured. NBI's engineers ran them
through the SMT process with various oven profiles using three different lead-free solder
paste formulations. The results were very satisfying. Only minor oven profile adjustments
were required to achieve high quality lead-free solder joints. After the successful SMT
reflow experiments, NBI engineers had the PTH components hand inserted and hand soldered
using both water-wash and no-clean lead-free wire solder formulations. Once again, the
results were much better than expected.
The boards were final inspected and function-tested. Again,
the results were good.