Planning quality inspection operations in multistage manufacturing systems with inspection errors

The management of resources dedicated for the appraisal of critical product quality attributes is a matter of increasing importance in multistage manufacturing systems. An interesting quality planning problem lies in the operational implementation of a quality inspection policy to select specific locations and machines for inspection activities. In this research, a mathematical model is developed for solving the inspection allocation and assignment problems in a multistage manufacturing system. The multistage system here considered processes part types with distinctive machine visitation sequences, and inspections can be performed on one of the several inspection stations with possible inspection errors. The computational process shows that as the problem size increases the number of inspection allocation possibilities and the computer system memory required becomes prohibitively large. Thus, three heuristic solution methods have been developed and are found to be effective in arriving at a near optimal solution with considerable savings in computational effort when compared with the optimization method based on complete enumeration. The heuristic solution methods are further compared with each other to determine their relative strength and weakness. A computer simulation is conducted to evaluate the methods developed.