Simulation analysis of the connecting transport AMHS in a wafer fab

This paper analyzes the performance of the connecting transport automated material handling system (AMHS) in a wafer fab. Discrete-event simulation models are developed in e-M Plant to study connecting transport in a simplified 300 mm wafer fab. A two-phase experimental approach evaluates the connecting transport. In phase I, the simulation results show that the connecting transport method has a significant effect on average travel time, throughput, and vehicle utilization. The relationship between vehicle quantity and the material flow rate is investigated in a simulation model for three connecting transport methods. The performance measures of these two factors can be predicted with a response surface method. However, none of the connecting transport methods outperforms the others in the different operating scenarios. In phase II, the connecting transport method is a mixture of the three existing methods. Thus, the optimum combination of these methods can be obtained with a mixture of experiment.