Performance modeling of a closed loop material handling system

Abstract

An integrated manufacturing system consisting of a set of work stations, a loading and an unloading station linked by a closed loop material handling system is considered. Each work station has a set of machines and a limited local storage, is capable of processing workpieces belonging to the same family of parts, and is connected to an unloading station. Each workpiece requires only one stage of operation, which may receive it from either one of the work stations. The workpieces enter the system at the loading station, recirculate along the material handling system until they are processed by one of the work stations, and then leave the system through the appropriate unloading stations. The asymptotic performance of the above system is modeled by a queueing network model. Each work station is modeled by a G/M/ S/K queueing system with generally distributed interarrival times, Markovian processing times, S machines, and a local storage of size K. The flows of workpieces inside the system are approximated by a two parameter method. Furthermore, two parametric methodologies are suggested to control the congestion along the material handling system. Finally, numerical results are provided and approximation outcomes are compared against those from a simulation study.