Performance Prediction of Flexible Manufacturing System using Queueing Networks

In the present paper we study the flexible manufacturing system (FMS) consisting of small manufacturing cells. The performance modelling of an FMS has been done by considering the individual manufacturing cells as closed queueing networks and the integrated manufacturing system as an open queueing network. Each manufacturing cell consists of a number of stations and a material handling device (MHD). The stations are arranged in series; the last station wherein inspection takes place is governed by Bernoulli feedback. We consider the inspection schedule such that when the operation of a job is completed at r^th station, it enters (r+1)^th station i.e. the inspection station. When inspection of the job is completed at (r+1)^th station, it enters either (r+3)^th station for unloading or enters (r+2)^th rework station for satisfactory operation with some probability. We formulate the inter-departure times of the loading/ unloading (L/U) station as a phase type distribution and find the mean and variance of the throughput process. We have given a numerical example for the illustration purpose which validates the algorithm proposed for computational purpose.