Modelling, analysis and design of computer integrated manufacturing systems.

In the present climate of global competition, manufacturing organisations consider and seek strategies, means and tools to assist them to stay competitive. Computer Integrated Manufacturing (CIM) offers a number of potential opportunities for improving manufacturing systems. However, a number of researchers have reported the difficulties which arise during the analysis, design and implementation of CIM due to a lack of effective modelling methodologies and techniques and the complexity of the systems. The work reported in this thesis is related to the development of an integrated modelling method to support the analysis and design of advanced manufacturing systems. A survey of various modelling methods and techniques is carried out. The methods SSADM, IDEFO, IDEF1X, IDEF3, IDEF4, OOM, SADT, GRAI, PN, 10A MERISE, GIM and SIMULATION are reviewed. The majorities of these contain graphical components and therefore, fulfil basic modelling requirements. In addition, these methods represent a comprehensive sample of manufacturing systems modelling methods. A manufacturing system comprises different sub-systems including physical, information and decisions sub-systems. These sub-systems can be modelled using a combination of the methods described i.e. GRAI for decision systems, IDEFO for physical systems, simulation for dynamic aspects, etc. A novel framework for comparing the modelling methods selected is developed using a number of factors derived from CIM and modelling requirements. The study discovered that no single modelling method or technique could model all the different aspects of a manufacturing system or achieve integration between system domains at both static and dynamic levels. As a result, it was concluded that there was a need for an integrated modelling method for the analysis and design of complex manufacturing systems. To overcome these problems, a novel integrated modelling method called GI-SIM has been developed. The method is composed of four modelling components GRAI grid, IDEFO, IDEF1X and SIMAN/ARENA. GI-SIM integrates these four tools to form a complete method, which combines the advantages of existing modelling methods and eliminates their shortcomings. The method developed is evaluated using a case study carried out in a UK company manufacturing electric motors. It is also tested for the design and specification of CIM system components (CAD, CAPP, CAM, etc.). The case studies demonstrate that GISIM achieves two important types of modelling integration; the first is a vertical integration between different levels of abstraction (conceptual, structural and dynamic) and the second is a horizontal integration between five modelling domains (decision, functional, information, physical and dynamic). In addition, the method is easy to learn and use, and sufficiently flexible to model any system function according to its related objectives. The findings of this research and recommendation for future research are presented in the final chapter.