Optimal design of an inspection station in a Flexible Manufacturing System-Analysis of an FMS using a closed queueing network model (Part III)

Inspection of finished products is necessary to ensure the required quality after all operations of jobs have been completed at workstations in a Flexible Manufacturing System. Since full inspection of finished products is ideal but too expensive to realize, the authors adopt a policy of partial inspection according to prespecified ratio (inspection ratio). Under this policy, the two kinds of loss caused by defective products should be considered: One is a cost for reprocessing a defective product detected by the inspection and the other is both the intangible penalty and the cost for replacing a defective product shipped without inspection. In addition, equipment costs are necessary for installing inspection devices and pallets. An optimal design problem of an inspection station is formulated to maximize the gross profit derived by subtracting the sum of the total loss and the total equipment cost from the total gain of finished products. An efficient solution method to obtain the optimal values for the number of inspection devices, inspection ratio and the number of pallets is proposed by exploiting three conjectures newly introduced. [In Japanese.]