Browsing by Subject "Cellular manufacturing systems"

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Open Access
Design of cellular manufacturing systems using a holonistic approach
(1998) Türkcan, Ayten
Cellular manufacturing is application of group technology to mcinufacturing. Cellular manufacturing system design problem involves the identification of part families, machine groups and layout of cells, and the selection of tools, fixtures and material handling equipment. In this study, part family and machine cell formation, and within-cell hiyout problems are solved simultaneously by using a holonistic approach. A mixed integer programming (MIP) model is proposed to form completely independent cells. The model maximizes total profit under cell size, within-cell layout, machine capacity, low utilization and low profit level constraints. Since it is difficult to obtain a feasible solution to the proposed model in a reasonable computation time, a local search heuristic based algorithm is proposed. The first two stages of the algorithm are used to find a feasible solution to the MIP model and the third stage provides an alternative solution with intercell movements. The proposed algorithm finds feasible solutions to the problem in recisonable computation times.
Open Access
Effects of product variety in technology selection decision for cellular manufacturing system design
(2003) Yayla, Hesna Müge
In today’s world, customers expect product variety. However, non-uniform products complicate the manufacturing processes significantly. In this study, we solved the cellular manufacturing system design and the technology selection problems simultaneously while taking the changing market dynamics into consideration. Cellular manufacturing system design problem aims the identification of existing part families and machine groups, while the technology selection decision determines the appropriate technology for the facility. In order to integrate the market characteristics in our model, we proposed a new cost function. Further, we modified a well known similarity measure in order to handle the operational capability of available technology. This new coefficient is employed at the identification of part families. The technology selection decision is based on the individual properties of parts, namely the production volume, variability of the demand, and the design stability of the part. Integration of the product variety at the design stage leads us to the use of flexible machining systems and dedicated manufacturing systems at the same facility. In the thesis, our hybrid technology approach is presented via a multi-objective mathematical model. A filtered-beam based local search heuristic is proposed to solve the problem efficiently
Open Access
Management of product variety in cellular manufacturing systems
(Springer, 2005) Akturk, M. S.; Yayla, H. M.
In today's markets, non-uniform, customized products complicate the manufacturing processes significantly. In this paper, we propose a cellular manufacturing system design model to manage product variety by integrating with the technology selection decision. The proposed model determines the product families and machine groups while deciding the technology of each cell individually. Hedging against changing market dynamics leads us to the use of flexible machining systems and dedicated manufacturing systems at the same facility. In order to integrate the market characteristics in our model, we proposed a new cost function. Further, we modified a well known similarity measure in order to handle the operational capability of the available technology. In the paper, our hybrid technology approach is presented via a multi-objective mathematical model. A filtered-beam based local search heuristic is proposed to solve the problem efficiently. We compare the proposed approach with a dedicated technology model and showed that the improvement with the proposed hybrid technology approach is greater than 100% in unstable markets requiring high product varieties, regardless of the volumes of the products.
Open Access
Polyhedral Approaches to Hypergraph Partitioning and Cell Formation
(1994) Kandiller, Levent
Hypergraphs are generalizations of graphs in the sense that each hyperedge can connect more than two vertices. Hypergraphs are used to describe manufacturing environments and electrical circuits. Hypergraph partitioning in manufacturing models cell formation in Cellular Manufacturing systems. Moreover, hypergraph partitioning in VTSI design case is necessary to simplify the layout problem. There are various heuristic techniques for obtaining non-optimal hypergraph partitionings reported in the literature. In this dissertation research, optimal seeking hypergraph partitioning approaches are attacked from polyhedral combinatorics viewpoint. There are two polytopes defined on r-uniform hypergraphs in which every hyperedge has exactly r end points, in order to analyze partitioning related problems. Their dimensions, valid inequality families, facet defining inequalities are investigated, and experimented via random test problems. Cell formation is the first stage in designing Cellular Manufacturing systems. There are two new cell formation techniques based on combinatorial optimization principles. One uses graph approximation, creation of a flow equivalent tree by successively solving maximum flow problems and a search routine. The other uses the polynomially solvable special case of the one of the previously discussed polytopes. These new techniques are compared to six well-known cell formation algorithms in terms of different efficiency measures according to randomly generated problems. The results are analyzed statistically.