New Heuristics to Minimize the Mean Flow Time for Static Permutation Flowshop Problems

Abstract

This paper presents three new heuristic procedures in an attempt to improve the solution’s quality of an earlier proposed heuristic in the literature. The heuristcis are developed to minimize average flow time in static and dynamic flexible manufacturing cell environment for n-job m-machine problem. The first heuristic is a modified version of Chan and Bedworth’s heuristic (Inter. J. Prod. Res., Vol 28, pp. 2037-2049, 1990) which attempts to improve its solution’s performance. The second heuristic is based on the development of an index function to select a job to be appended to a partial sequence. Finally, a simulated annealing algorithm is developed to be also used for testing and comparisons. The three heuristics along with that of Chan and Bedworth are tested by solving 180 randomly generated problems. Based on the results of this experemintal work, the improved Chan and Bedworth’s heuristic was superior to the other three heuristics when minimizing the average flow time. With respect to the makespan as an objective function, the heuristic using the index function outperformed the remaining heuristics.