A sequencing problem for mixed-model assembly line with the aid of relief-man

Abstract

There usually exist large variations in assembly times at mixed-model assembly lines depending on difference of product-models. To increase efficiency of line handling under such circumstance, this paper concerns with a sequencing problem for the mixed-model assembly lines where each product is supposed to be assembled within the same cycle time. Then, we formulate a new type of the sequencing problem minimizing the weighted sum of the line stoppage times and the idle times, and propose a new sequencing method with the aid of Relief Man (RM). Since the resulting problem refers to a combinational optimization problem, we develop a hybrid method that applies meta-heuristics like SA (Simulated Annealing) together with TS (Tabu Search) in a hierarchical manner. Finally, we examine the effectiveness of the proposed method through computer simulations and show the advantage of using RM against various changes in production environment.