The effect of tool sharing on reliability of flexible manufacturing systems.

Abstract

A major consideration in opting for reliability and flexibility in Flexible Manufacturing Systems (FMSs) is to enhance the availability of resources in order to maintain an uninterrupted production. This means that sufficient redundancies must be foreseen at the preliminary production planning stage to cope with the random breakdowns of components. In this research effort four mathematical models were developed to determine the spare requirements for tooling system in FMSs, so that a desired system reliability is achieved with minimum cost and/or tool slots occupancy of the system. For the first time, the influences of tool sharing on cost, reliability, spares requirement, and tool magazines capacity of FMSs, in which tools and tool transporter are subject to general failure distributions, were analyzed. The developed models have been applied to a hypothetical example and the computational results were compared, for the case where tool sharing is not applicable and where tool sharing can be implemented. Several sets of sensitivity analysis were also performed on different system parameters through which the effects of the number of tools shared among machines, the required system reliability, and operating times for tools on the system reliability and cost were assessed.