| Highly integrated manufacturing processes are always very difficult to operate because of system complexity, inherent nonlinearity, various uncertainties, and heavy system interactions. Facing the challenges of global economical competition and increasingly stringent environmental protections, industries have been making tremendous efforts on cost cutting, quality improvement and pollution prevention (P2). In this endeavor, one of the most effective ways is to characterize and optimize the processes so that the economical, technical and environmental goals can be simultaneously achieved.; The key to achieve the optimal production and P2 of a manufacturing process is to have a deep understanding of process fundamentals and to develop optimal process operational strategies. This research centers on the development of a set of general, integrated modeling and optimization methodologies for two classes of coating processes, automotive and metal finishing, each of which consists of a number of heavily interacted sub-processes. By using the large-scale system theory, chemical engineering fundamentals, and non conventional computational techniques, an integrated modeling methodology is introduced. First-principle modeling and empirical modeling techniques are combined with non-conventional modeling techniques using artificial intelligence, fuzzy logic, and neural network to construct computer-aided tools. It is shown that the tools can represent and manipulate the knowledge at different levels, ranging from physical, logical, epistemological, conceptual, to linguistic levels, in forms both numerical and symbolic, structured and unstructured, precise and imprecise. With this modeling scenario, hierarchical and simultaneous system optimization strategies are also proposed. The proposed methodology is used for two types of industrial processes: (i) an automotive topcoat spray and curing process where the coating quality and energy reduction are the main concerns, and (ii) an electroplating process where the reduction of chemical solvent, wastewater and sludge, as well as the improvement of cleaning and rinsing quality are targeted. In these applications, the novel concepts and methodologies of proactive quality control (PQC) of automotive polymeric coating and profitable pollution prevention (P3) of metal coating are introduced. |
