Research On The Optimization Methods Of Manufacturing Plant Layout With System Implementation

Developing a plant layout is an important step when designing manufacturing facilities due to the impact of the layout on material handling cost and time, on throughput, and on productivity of the facility. Plant layout problems are now faced by industry more frequently due to a change from mass production towards more flexible batch production. And as a result, one has to face a lot of new issues which are significantly different from the traditional layout problems in the design of a plant layout. In this dissertation, several key issues involved in the design of the widely utilized cellular layout (GT layout) are studied, including the modeling, algorithms and visual layout design technologies.In general, the full layout design requires four major steps: (1) Cell formation, i.e., to group parts into part families and machines to machine cells; (2) Cell layout (intra-cell layout), i.e., to assign machines or work stations within each cell; (3) Cell system layout (inter-cell layout), i.e., to arrange cells within floor; (4) material handling (MH) system, i.e., to design material flow paths between the pickup/delivery (P/D) stations. The primary objectives in the formation and layout of manufacturing cell are concerned with minimizing the number and cost of inter-cellular moves and maximizing the utilization of machines.Traditionally, the optimization processes for the plant layout have been carried out sequentially and separately. Solutions obtained by this means can be far from the total optimum. To avoid the drawbacks of traditional layout methods, based on the principles of concurrent engineering, an integrated approach to the problem is proposed, which attempts to design the plant layout concurrently.A way to reduce the material handling cost without compromising the component functionality is to choose satisfactory design options. Also, the alternative processing route is one of the important design factors for the cell formation problem. Based on a full exploring of the close relationships among component design/process planning, cell formation and layout design, an integrated method for the formation of parts and machine families is then developed, together with the corresponding GA-based algorithm for solving it. Compared with those existing approaches, the proposed procedure attempts to solve cell formation, process planning and intra-cell layout in a single step, which improves the design quality and makes the problem's solving simpler.Although the inter-cell layout problem is similar to a block layout problem in terms of concepts, models, and solution procedures, some definite differences between them make the inter-cell problem more complicated and thus, special issues need to be considered in the layout design. In this dissertation, an approach for solving the inter-cell layout problem is presented. The layout problem is modeled based on a slicing tree structure, considering the I/O station sides for each cell. This proposed approach incorporates the GA and SA with a new coding scheme which ensures that the search can cover the full solution space. The computational results show that the proposed approach is capable of obtaining optimal solutions for the test problems even with a higher reduction of the objective function value as compared with other methods. Moreover, it is also observed that the parameter set chosen for the hybrid algorithm is more relaxed than that of GA or SA alone.It has been known that both the cell system layout (CSL) problem and material handling system design problem are of NP-hard combinational problems. In this paper, an integrated approach to the problem is proposed, which attempts to design CSL and flow path structure simultaneously. The cells in question are assumed to be shape fixed and have pre-determined pickup/delivery (P/D) stations. A sequence-pair based CSL-generating algorithm allows cells to be placed at any possible positions on a continuous floorplan and leads to a corresponding feasible CSL. A grid graph for the CSL is accordingly constructed to provide possible flow paths for the layout. Then, the sum of the traveling distances, determined by the shortest path algorithm, is used to evaluate the CSL. These steps are embedded into a GA that searches the solution space to obtain optimal layouts based on the contour distances between the P/D stations. A comparison of the computational results with the existing methods indicates that the proposed approach is a viable alternative for effectively generating layout designs for CMS.Since it is very difficult to model all kinds of factors involved in a detailed layout design problem mathematically, an AR-based visual layout design system is developed. The prototype system shows that, when solving detailed layout problem, AR gives more promise than other possible techniques, say, VR.Finally, based on the aforementioned techniques, a prototypic software system is developed, which can be used to make the layout designer's work easier. Besides, the running cases of the system are also given.