In-process inspection and correction facilities subject to errors

Inspection error is one important cause of consumer dissatisfaction particularly in consumer products. For decades, inspection for quality of product has been performed mostly at the end of production line. Therefore, any nonconformance from product's specification is known at the time they are inspected. One solution is applying in or between process's inspection. This becomes available by the use of sensor technology that is no longer expensive for specific purposes. Moreover, necessary in or between process's correction can be performed before parts or components are manufactured by the next process. In this study, an in-process inspection and correction facility is considered. Two sequences are compared, the first consists of process and inspection, where correction is performed by the same process. The second includes an additional correction facility and any nonconformance is corrected separately. Process, inspection and correction costs are considered as an economical measure of the accepted product for both sequences. On the other hand, an accepted product is not always perfect, it varies around its target value due to variation of process or correction and inspection error, finally resulting in loss to the consumer. A model of the sum of these costs and losses is used to determine the best sequence.<>