Due-date Based Multi-period Part Selection for Flexible Manufacturing Systems with Controllable Processing Times

Abstract

This study considers a multi-period part selection problem for flexible manufacturing systems in which part processing times are not given, but can be changed. The problem is to determine the set of parts and their processing times while satisfying the processing time and the tool magazine capacities in each period of a planning horizon for the objective of minimizing the sum of part processing, earliness/tardiness, subcontracting and tool costs. Some practical considerations such as the number of available tool copies, tool life restrictions and tool sharing are also considered. An integer programming model is developed to represent the problem mathematically. Then, due to the complexity of the problem, we propose two-phase heuristics in which an initial solution is obtained by a greedy algorithm under initial processing times and then it is improved using various local search methods while adjusting part processing times. To test the performances of the heuristics proposed in this study, computational experiments were done on a number of test instances, and the results are reported