Research On The Effective Shop Floor Layout Design In Multi Product Manufacturing System

Manufacturing companies must reduce cost to survive in today's economy. In the last few decades, many companies began to focus on increasing productivity with optimized utilization of human resources. Due to the optimization in labor resources, investments in equipment costs have increased. Among the consequences of these policies is a significant reduction in direct labor cost which in effect has made material handling cost more important than ever before. Material handling cost reductions can be obtained by designing efficient layouts. Efficient layouts are obtained by solving machine and facility layout problems effectively which can keep the organization competitive in global market.There is an emerging consensus that traditional layout designs cannot meet the requirements of multi-product manufacturing systems and there is a need for designing an effective new layout which can cope with the needs of multi product enterprises. An extensive literature review has shown that the facility layout problems are generally solved by process layout, product layout or cellular layout. However the requirements of an efficient layout can be fulfilled more economically by using the hybrid layout which is the type that combines the features of all three basic types of layout.In this research, a step by step methodology has been developed to design/redesign an effective shop floor layout. Performance indices for efficient layout are evaluated and prioritized. The Important indices selected for formation of layout design are flexibility, batch size of products, cost of equipments, product volume, machine to machine distance and available space. After evaluating the performance indices for layout design, a technique for the formation of effective shop floor layout is developed. The size of the problem is reduced by combining the products which have similar product type and sequence of operations. Machines for different types of layouts are segregated based on machine utilization and product similarities. The placement of machines in cellular, process and product type layouts is based on the percentage utilization of machines for specific products to be routed through these machines.The placement of machines within a given layout is an important decision to optimize the performance measure. Genetic algorithm (GA), being an innovative approach for solution of facility layout problem has been used to assign machines to locations within a given layout for the entire system. Usually, in the cell formation problem only the material handling cost is considered, while in this research, before going to develop a fitness function a thorough research on all the factors effecting the layout design are reviewed and prioritized by using Fuzzy/Analytical Hierarchical process. A new mathematical model comprising of machine to machine distance and frequency of flow for specific product order is designed for solving cell formation. A new and improved cross over method is implemented in GA for achieving better optimal solution and to avoid entrapment of inferior solution.In order to test the effectiveness of the proposed methodology, an evaluation is carried out by solving a medium size facility layout problem which contains the twenty three products and twenty types of machines. The problem has been solved by using developed methodology. For comparison with the newly developed layout, a cellular layout for the same problem is solved by using well knows rank order clustering technique (ROC).The simulation software for the performance evaluation and comparison of both of the manufacturing systems was carefully chosen using AHP based multi criteria decision making technique. The analysis and evaluation of the both manufacturing system is carried out by integrating simulation with Design of Experiments (DOE). A full factorial design of experiment is conducted to see the response of both of the systems in term of flow time. The response is measured under different conditions of process parameters; these process parameters include designed layouts, machine set up time, machine down time, number and type of transporter, batch size of the product and the scheduling and dispatching rule. The purpose was not only to measure the response of both of the systems but also to determine the effect of these process parameters and how response can be improved by adjusting appropriate level of these factors.At the end the Stata statistical software package has been used to perform statistical analysis. The simulation results indicate that facility layout designed by proposed methodology outperforms the cellular type of layout. Data analysis shows that it is not only the type of layout responsible for making the manufacturing system efficient, there are also several factors which can contribute significantly to the performance of manufacturing system.