The first accomplishment was a passive sensor and related optics to measure infrared emissions from the weld during processing. The monitor can tell a worker on the factory floor about the weld's penetration depth and surface quality. Bad welds are flagged and the monitor can automatically signal the system to change weld parameters or laser power levels. The laser welding monitor can be used with steel, aluminum and magnesium. Because the monitor senses the integrity of the weld remotely, destructive weld evaluation can be used less frequently.
Every weld is critical in safety-related applications, such as in automotive airbag housings.
Several welds are performed to manufacture the airbag housing which has to be leak proof and tested. The lack of competent weld monitoring has contributed to defect rates of several percent. With more than 10 million air bags produced each year, the Argonne-developed monitor could save millions of dollars in this business alone. Partner Spawr Industries, Inc. integrated the monitor into the laser beam delivery system, and provides a commercial version. This technology received a 1997 Federal Laboratory Consortium Award for Excellence in Technology Transfer.