A scatter search method to minimise makespan of cell scheduling problem

Scheduling problem in a Cellular Manufacturing System (CMS) environment is treated as group scheduling problem, which assumes that all parts in a part family are processed in the same cell and no inter-cellular transfer is needed. In a typical CMS environment, however, there could be some exceptional parts, which need to visit machines in the other cells. This fact limits the applicability of group scheduling approaches. This paper addresses the scheduling of manufacturing cells in which parts may need to visit different cells. These problems are solved in two stages namely intra-cell scheduling and inter-cell scheduling. Through inter-cell scheduling, the sequence of parts within manufacturing cells is determined. In inter-cell scheduling, the sequence of cells is obtained. Scatter Search (SS) is proposed to solve the intra-cell and SVS algorithm is to solve inter-cell scheduling problem. The performance of proposed SS algorithm is evaluated on benchmark problems selected from literature. The results reveal that the SS algorithm performs better than NEH heuristic method in the selected benchmark problems with respect to average makespan.