Scheduling flexible flow lines with sequence-dependent setup times

This paper examines scheduling in flexible flow lines with sequence-dependent setup times to minimize makespan. This type of manufacturing environment is found in industries such as printed circuit board and automobile manufacture. An integer program that incorporates these aspects of the problem is formulated and discussed. Because of the difficulty in solving the IP directly, several heuristics are developed, based on greedy methods, flow line methods, the Insertion Heuristic for the Traveling Salesman Problem and the Random Keys Genetic Algorithm. Problem data is generated in order to evaluate the heuristics. The characteristics are chosen to reflect those used by previous researchers. A lower bound has been created in order to evaluate the heuristics, and is itself evaluated. An application of the Random Keys Genetic Algorithm is found to be very effective for the problems examined. Conclusions are then drawn and areas for future research are identified. (C) 2003 Elsevier B.V. All rights reserved.