Screening program effectiveness

During the last ten to fifteen years, active and passive device screening has received considerable discussion. The literature contains well over 100 papers dealing with various aspects of part screening and the cost effectiveness of such programs. Although these reports are generally favorable toward the decision to utilize some type of 100-percent testing beyond the manufacturers normal end-of-line testing, most commercial systems and some military systems are routinely assembled using unscreened parts. From this it appears that management's decision variables must differ substantially from those discussed in the various pro-sereening papers. This paper attempts to provide a general means of evaluating a screening program's effectiveness which utilizes terminology appropriate to product management decisions. Any systematic evaluation should provide guidance relative to three areas of concern. 1) Should device screening be imposed for product X? 2) If so, which screens should be used? 3) How can we keep the program dynamic and sensitive to the changing technology? A benefit/cost model utilizes information developed by marketing, manufacturing, and reliability engineering to estimate the total impact of a screening program and provides a quantitative basis for decision making.