Estimation of tool requirements in single-stage multimachine systems

As machine tools become more versatile, single-stage multimachine systems (SSMS) have emerged in which all the operations of a part are performed on a single machine. In this system, parts stay on a machine all through their operations while tools are delivered to the machines as requested. The performance of the system is then restricted by the tooling conditions. This paper addresses the problem of how many tools should be maintained in an SSMS under a tool sharing environment. An open queueing network-based approach is proposed which not only determines tool requirement levels but also predicts the tool waiting time given the tooling capacity. The tool life and tool delivery are taken into consideration in determining the tool requirement levels. A simulation study is performed to evaluate the proposed approach.