Operatonal design of cellular manufacturing systems for robustness

Customer expectations for high quality custom products, shortening product life-cycles, advances in manufacturing technologies and increased global competition enforce companies to replace their legacy production systems with advanced manufacturing systems and technologies. Cellular manufacturing systems (CMS), an application of group technology philosophy to manufacturing is adopted by companies in this context as it provides an effective and efficient system structure with low-cost automation. Cellular manufacturing benefits should be evaluated hollistically as transformation of entire system layout is required for implementation. As companies implement cellular layout they reorganize their functional "job-shop" layout into cellular layout composed of individual manufacturing and assembly cells. A properly implemented cell combines the advantages of flow-lines with flexibility of job-shops constituting a hybrid system structure. This thesis aims to present a framework for operational design of cellular manufacturing systems for robustness. Originality of our approach stems from its consideration of operational design parameters, multi-objective optimization and system robustness. Taguchi's design philosophy and statistical techniques of response surface methodology (RSM) are combined in a simulation setting to form an operational design strategy for group technology cells considering system robustness. Simulation environment facilitates testing alternative design configurations and systematic introduction of variability during experiment in terms of noise variables. Simulation experiments frees experimenters from cost and time constraints faced in real-world environments. Results indicate that robust designed cells exhibit much less performance variability compared to nominal optimal configurations for all performance characteristics considered with minor decrease in mean performance values. Robust designed engineering systems will perform as expected under uncertainty faced by cells in real-world environments. Keywords: Simulation, Robust Design, Taguchi Method, Lean Manufacturing, Cellular Manufacturing Systems, U-shaped Line, Response Surface Methodology, Robust Optimization, Manufacturing Cell, Assembly Cell