Design of material flow networks in manufacturing facilities

In this paper we consider the design of material handling flow paths in a discrete parts manufacturing facility. A fixed-charge capacitated network design model is formulated, and two efficient heuristics are proposed to determine near-optimal solutions to the resulting NP-hard problem. The first heuristic iteratively adjusts the arc fixed costs and selectively includes arcs in the flow network until a feasible network is obtained. The second heuristic partially explores the problem state-space. Both heuristics are tested against an implicit enumeration scheme used to obtain optimal solutions for small examples. For more realistic cases, solutions are compared to lower bounds obtained by linear programming relaxation of the mixed integer program or by an iterative dual-ascent algorithm. Results indicate that, on average, the heuristics provide good solutions in reasonable time. The proposed methodology is applied to design flow paths of an existing manufacturing facility. The role of the flow path network problem in integrated shop design is also discussed.