Rosin fluxes used in a traditional open air mass soldering process serve three purposes: 1)removal of oxides from metal surfaces, 2) protection of these surfaces from further oxidation and 3) reducing the surface tension of the liquid solder. Waste generated form this process include VOC emissions from rosin and isopropyl alcohol, waste lead dross from oxidation of the solder and spent ozone depleting chemicals used in the final cleaning process.
Texas Instruments, in cooperation with the Navy, Motorola, Sandia National Labs, IPC and other industry partners developed and implemented a Controlled Atmosphere Soldering (CAS) system using low residue flux that eliminated or reduced much of the wastes associated with mass soldering. By soldering under inert conditions (i.e. nitrogen), flux removes oxides from to-be soldered metal surface, the re-oxidation of the to-be-soldered metal surface is eliminated. The final cleaning could be satisfactorily done using an aqueous cleaner instead of ozone depleting solvents.
Details of Reductions
Additional Information :
Process development, equipment purchases and implementation cost approximately $400,000. This project has paved the way for a major change of direction in the assembly of military electronic products. Although it was initially pursued for environmental reasons, the project has resulted in a significant reduction in manufacturing costs. It is self sustaining financially with a simple payback of 1.5 years on investment.