Performance modeling of a manufacturing cell with a single material transporter: An approximation

We consider a flexible manufacturing system with a number of workstations, a single material transporter, and a common storage space of finite capacity. The material handling delay times are explicitly considered in the model and assumed to follow a two-stage Coxian distribution. The material processing times on a workstation also have a two-stage Coxian distribution. The routing of parts within the system follows a Markov chain. An approximate performance model is developed and the results are compared with the exact or simulation results. We also investigate how this performance model compares to a simulation with deterministic routing and processing times. Finally, we study the effect, on the performance measures, of ignoring the material transporter or of modeling the transporter as a central server with aggregation of routing information.