Evaluation of dispatching rules for flexible manufacturing system

Abstract

In this project, three dispatching rules are evaluated based on system flexibility in a flexible manufacturing system (FMS). The three types of dispatching rule are earliest due date (EDD), least reduction in entropy (LRE) and least relative reduction in entropy (LRRE). The system is studied under two input rules, level production rate (LPR) and same part type (SPT), three levels of system availability (50%, 75% and 95%) and three levels of work-in-progress (WIP), 18, 27 and 36 fixtures. A static dispatching rule (EDD) is used to compare the performance with two entropy-base dispatching rules, namely LRE and LRRE. The manufacturing system would be a medium size cell which consists of 5 machines and 3 product types. The performance measures of interest are cycle time and part throughput rate.

Simulation models of the above-mentioned FMS were meticulously developed by using Arena simulation software. Results are obtained from all the different combinations of system availability, input rule, WIP and dispatching rule. Then these simulation results are used to evaluate dispatching rules by analyzing manufacturing system performance, in terms of cycle time and throughput rate. The results of system performance indicated that LRRE is a better dispatching rule to implement in FMS, to better cope with any unpredictable disruptions and uncertainties.