Development of a generic model for a manufacturing management system
The work reported in this thesis is related to the development of a generic model for a 'make-to-stock’ manufacturing organisation. This research is based upon the hypothesis that every type of manufacturing company should have a generic model. The objectives of the model are first, to help SNIEs (Small and Medium sized Enterprises) who cannot afford external help and second, to fulfil the need for modelling that arose from a review of modelling literature. These were the basic driving forces in carrying out this research and from which the objectives are derived. A survey of various system design and analysis methods was carried out. Initially SSADM, SADT, IDEFO, NMRISE, STRIM and GRAI were selected for the study. The reason for the selection of these methods was that each contained graphical tools and fulfilled the requirements for modelling. Further investigation showed GRAI and IDEFO to be the most suitable methods for modelling manufacturing systems and these were selected for further investigation. A direct comparison of the GRAI and IDEFO methods was carried out using a case study. The results of this indicated that the GRAI method was the most suitable for the analysis and design of manufacturing systems and demonstrated advantages over the IDEFO method. For this reason the GRAI method was selected and applied to case study 'make-to-stock! manufacturing organisations. The case studies demonstrated that several similar characteristics existed in 'make-to-stock’ manufacturing organisations, supporting the hypothesis of the research. The case studies also indicated that the application methodology had some significant drawbacks. On the basis of this investigation, a detailed methodology to apply the GRAI method was formulated and validated using a further detailed case study. After the methodology had been validated, it was used to develop a generic model for a 'make-to-stock' manufacturing organisation. The model developed presents the activities carried out at the strategic, tactical and operational levels of the management hierarchy. Details of typical decision horizon and review periods are also included in the model. The thesis presents the first detailed methodology for applying the GRAI method and first application to develop a generic model. It also presents the first detailed comparison between the IDEFO and GRAI methods. The findings of this research and recommendations for future work are presented in the final chapter.