Multi objective design of mixed model assembly line

Line balancing is a tool that can be used to optimize the workstation or assembly line throughput. Mixed-model assembly line is the line on which the simultaneous production of more than one model is realized. In today's industries and global market, due to the increasing competitiveness, companies try to enhance production flexibility by reducing their batch sizes and increasing product varieties. Because of this competitiveness, single-model production is less common than multi/mixed model production. Due to the enlarged number of models, the design of an mixed model assembly system becomes more complicated. In this study firstly, an mixed integer programming model have used for balancing and selected assembly routes for products to minimize total transportation time. Then it is evaluated cost of stations to minimize time and cost in mixed model assembly line problem with mixed integer programming. This problem is solved with goal programming to reach these objectives. The developed models are applied to both data sets aquired from the literature and the real data from the Arçelik A.Ş. The model is applied to the LCD assembly line of the company. Then results are assessed. Different scenarios based on time and cost while considering company's goals are assessed and then results are presented to the Company's managers.Results of presented scenarios show 0 value for positive deviations of objectives. Cycle times and balancing loss are computed for station loads and the less loss balancing is selected, otherwise, the scenario which has less deviations between stations is selected among scenarios. Goal values for this scenario is fixed more convenient goals for the company. At last phase, sensitivity analysis is made for selected scenario to show sensitivity of paramaters in objective function and goal values. For this in ILOG OPL 12.2 Optimization programming is used.