A new multi-objective approach in order to balancing and sequencing U-shaped mixed model assembly line problem: a proposed heuristic algorithm

Mixed model production is the practice of assembling different and distinct models in a line without change-overs responding to sudden demand changes for a variety of models. In this paper, to achieve a combination of balancing of the tasks and sequencing of models, both the balancing and sequencing problems are considered simultaneously. Three objective functions including: minimizing the cycle times, minimizing the wastages in each station, and minimizing the work overload by considering a multiple objective in both sequencing and balancing problem are investigated. One of the characteristics of this study is minimizing the wastages. The combination of those objectives in such problems has not been studied yet. Also, we propose a new heuristic algorithm and indicate that our results can be improved in the algorithm from the initial solution. Finally, the straight lines and U-lines in our problem are investigated; therefore, a decision maker can decide about the shape of assembly lines and compare the results in these cases.