A MATHEMATICAL-MODEL FOR CELL-FORMATION CONSIDERING INVESTMENT AND OPERATIONAL COSTS

The majority of the cell formation models consider grouping of parts a nd machines, based on clustering techniques. The performance of cells thus formed indicates that the cellular systems perform more poorly in terms of work-in-process inventory, average job waiting time and job flow time than the improved job shops. However, they have superior per formance in terms of average move times and setup times. The main reas on for such a poor performance is that the current cell design procedu res do not consider the operational aspects during the cell formation. Therefore, the objective of this paper is to consider the investment and operational costs simultaneously during the design of a cellular m anufacturing system. For this purpose we develop a mixed integer progr amming model and illustrate the trade-off relationships between the in vestment and operational variables, such as sequence dependence setup, machine idle time, part inventory, part early and late finish (compar ed with due date), by considering examples. Computational experience i s provided for randomly generated test problems.