Balancing Machining Lines: a Two-phase Heuristic

This paper considers balancing machining lines with parallel machines and sequence-dependent setup times. The goal is to minimize the number of machines for a given cycle time. Such lines are paced, i.e. parts are moved from one station to the next with a given cadence (defined by the line cycle time). At least one machine is installed at each station. Parallel machines are to be used when the corresponding station is overloaded, i.e. the total time of all operations assigned to the station exceeds the line cycle time. Moreover, station workload depends on the sequence in which the operations are executed because the setup times related to the changes and displacements of tools, rotations of the part, etc. In this paper, a heuristic method is proposed for the resolution of this problem. An industrial example is presented and numerical results are reported.