Heating up

Steve Scheiber, Technical Editor -- Test & Measurement World, 11/1/2005

As optical and x-ray inspection techniques continue to improve, we sometimes lose sight of other technologies that could add to our quality arsenal. Infrared inspection has enjoyed a mixed history at best. Although infrared inspection is still used to inspect bare boards for shorts, its entry into loaded-board manufacturing proved less successful, suffering as much from a lack of corporate enthusiasm as from any drawbacks to the method itself. Circumstances encourage taking another look.

One of the challenges of increasingly powerful components is their heat dissipation. Concern has arisen that normal operating temperatures of some components can create "hot spots" on the board that approach tolerance limits of board substrates and other components.

As with visible-light and x-ray products, the resolution and sensitivity of infrared inspection hardware and software have improved dramatically in recent years. Although it might be argued that identifying locations with heat problems on boards during full-scale production would constitute closing the barn door after the horse has bolted, incorporating infrared inspection into prototype, pre-production, and initial ramp-up can minimize problems once full production begins.

Readers of this space will no doubt recognize that my fascination with this technique is far from new. Nevertheless, it could offer solutions in some situations where more conventional inspection techniques fall short.

Contact Steve Scheiber at sscheiber@aol.com.