Planning of Production Reliability Stress-Screening Programs

This paper describes qualitative and quantitative techniques for planning, monitoring, and evaluating stress screening programs. The techniques were developed under a recent study for the Rome Air Development Center. A model for use by reliability managers to aid in planning and evaluating stress-screening programs is presented. Guidelines are outlined for determining the applicability of screens to different equipment types and for selecting the proper level of assembly at which to apply the screens. An example of how the techniques are applied to a production screening program is provided. While stress screening is now widely employed throughout the defense industry and many experiments and studies on the subject have been conducted, the precise information needed to plan an optimum production stress screening program is still unavailable. Planning must rely on sound judgment and available data from experience. With the proper selection and placement of screens the stress-screening model is a useful tool in screen parameter selection and in providing a quantitative anticipation of screen results. A comparison of actual and anticipated results allows an evaluation of initial assumptions regarding the initial quantity of defective parts, the number of induced defects, and the true screening strength. Consistent differences between actual and anticipated results serve as the basis for altering the screening parameters and maintaining the most effective screening for the resources invested.