Reliability of an Environmentally Friendly Soldering Process for Printed Wiring Boards
Project Description and Significance
A major part of electronics manufacturing is the production of printed wiring boards (PWBs). Normally after soldering, the boards must be cleaned with solvents that contain ozone-depleting chemicals (ODCs). Since ODC production was banned after December 1995, and ODC costs and ODC-use labeling requirements are increasing, electronics manufacturers have been forced to consider alternative materials and processes. A new low-residue soldering process can eliminate the use of solvents by eliminating the cleaning step altogether. By eliminating this step, the low-residue soldering process not only helps protect the environment but also speeds up production, significantly minimizes waste streams, and reduces costs.
Sandia and Motorola, in a joint effort (a Cooperative Research and Development agreement, or CRADA), evaluated the reliability of PWBs manufactured with low-residue technology in a wave soldering application. This study showed that the reliability of PWBs produced with the low-residue process was at least as good as that of PWBs soldered with the traditional rosin flux/solvent cleaning process. The project gained wide national attention and resulted in Sandia receiving more than 350 inquiries about implementing low-residue soldering. These inquiries indicated that gaining military acceptance of low-residue technology was a major concern. To address this concern, Sandia formed a task force consisting of 11 organizations and representatives from the three military services to conduct an extensive evaluation of low-residue technology for military electronics applications.
Sandia's Contribution
Performance of the low-residue soldered boards was comparable to the rosin flux/solvent-cleaned control boards in all tests, even though the low-residue processes had not been optimized at any of the manufacturing sites. One of the partners used the test program and results to gain military acceptance of the low-residue process on 66 major military contracts, reducing their annual materials processing costs by 96%. Reports on both the project with Motorola and the task force evaluation are available from Sandia.
Future Work
Sandia is currently involved in efforts to couple low-residue soldering with lead-free solders and considerable interest has been expressed by companies wishing to collaborate on new environmentally conscious soldering technologies.
For further information, contact:
Dennis J. Anderson
Sandia National Laboratories, MS-0746
Albuquerque, NM 87185-0746
Phone: (505) 845-9837
e-mail: djander@sandia.gov
Submitted October 1996 Layout design by Wanda Mar.
Submitted October 1996