Waiting time optimization in queueing models of equipment with multiple preventive maintenance cycles

Abstract

Preventive maintenance activities perform important part in preventing unexpected failure and ensuring the reliability of the equipment. In the semiconductor manufacturing, preventive maintenance include many and complex tasks. According to the planning of PM, the cycle time and line performance are affected. In this paper a model is proposed that optimizes the new cycle of single PM and multiple PMs for minimizing cycle time with consideration of attached setups. This model consists of two parts. First, part is the queueing networks with sin-gle PM. Second part is the queueing networks with multiple PMs. The queueing networks are applied in the M/G/1-queue and G/G/m queue. The model is formulated as nonlinear programming problem with constraints. In order to solve this model, The matlab optimization toolbox is used. Since the model of G/G/m queue is ap-proximation, The optimal solution is not guaranteed. Thus, the results obtained have compared with a simulation model is made into the Arena 14.5 version and Opt quest.