Configuring layout in unidirectional loop manufacturing systems

This paper addresses the layout configuration problem of workstations in a uni-directional loop manufacturing system. In this popular unicyclic material handling facility, the material transporters depart from the input/output station, traverse each workstation exactly once, and then return to the input/output station. We show the important properties of this unidirectional material handling loop network. Based on these characterizations, both heuristic and branch-and-bound algorithms are proposed to solve such NP-complete layout problems. Computational experiments with problem sizes up to 100 workstations are reported. Both the problem size and the material flow density have been found to affect the solution quality and the computational efficiency. The proposed methods appear efficient and effective for solving these layout problems.