Abstract: With the increasing of demand diversification, manufacturing enterprises encounter challenges of demand uncertainty and fluctuation. Japanese Seru (Japanese style assembly cell) production system (SPS) has received more attention with its efficiency and flexibility especially under uncertain demand. More researches focus on how to implement Seru production system appropriately. However,most of current research focus on the deterministic demand. To enrich the research in this field, a line-Seru conversion problem is investigated in this paper. Considering the fluctuation of product demand, a multi-objective optimization model of line-Seru conversion problem is developed to minimize the expectation and variance of make span (MS). The minimized expectation of make span offers quick response to a production system with fast delivery. The minimized variance of make span represents the high system stability. The aim of this paper is to offer a method for formulating a robust Seru production system which can ultimately deal with the fluctuation of product demand. In order to obtain optimal solutions of this NP-Hard problem, an NSGA-Ⅱ (non-dominated sorting genetic algorithm Ⅱ) based algorithm is developed.Combining the benchmark data from Yu Yang et al[18] with fluctuation factors,numerical experiments are conducted to prove the effectiveness of the model and illustrate how to implement the method. The experiment results show that both delivery time and stability of SPS will be improved with considering the demand fluctuation. At the same time, performance of the system will decline with the increasing of batch size.

Key words: demand fluctuation, Japanese Seru production system, cellular manufacturing, multi-objective model