DOUBLE-STAGE INSPECTION FOR SCREENING MULTI-CHARACTERISTIC ITEMS

Final product inspection of a multi-attribute product, such as in the electronic assembly industry, involves expensive facilities. The corre lation among attributes may be used for reducing the efforts needed fo r screening the products; however, engineers without an appropriate st atistical-economical analysis tools do not take risks, and they design ate full inspection of each item. We propose a double stage inspection program for reducing inspection efforts. Assuming that the joint dist ribution is known, the conditional probability that a product is ''goo d'' may be evaluated conditional upon the observation of the product's first-stage inspected quality attributes. Then, an expected cost mini mization is implemented in order to decide whether a second inspection stage is required or a classification should be based solely on the f irst inspection stage. The cost factors include inspection and false c lassification. The method is illustrated on a real data set from a par ticular electronic product of Motorola-Arad Ltd.