Reliability optimisation of FMS with spare tooling

Tool reliability plays an important role in the performance cmd justificati on of flexible manufacturing systems (FMS). Failure of a single tool can ca use downtimes over the Entire system. This results in missing due dates, an d inferior products. Therefore, in order to justify the large capital inves tment associated with FMS, the system must perform in a reliable manner to give an acceptable or expected rate of return on capital. FMS reliability s hould be studied at the planning and design stages, as tool failures pose a major obstacle to achieving this objective. In this paper, a mathematical model has been developed to determine the spares requirement of the tooling system in an FMS, so that the desired system reliability is achieved and t he cost is minimised. The influence of tool sharing on cost, reliability, s pares requirement, and tool magazine capacity of the FMS are analysed. The tools and tool transporter are subject to general failure distributions.