Layout design for flexible manufacturing systems

The authors consider the layout design problem for flexible manufacturing systems, in particular the two most commonly used configurations-loop-conveyor and linear-track conveyor systems. Such systems may include machines of different dimensions separated by some required clearance between them: this means that distances between predefined locations cannot be used as in the traditional facilities layout problem, and the quadratic assignment problem (QAP) approach cannot be used to find a solution to minimize material handling. The authors model the loop-conveyor system as a QAP with an alternate, equivalent objective function; and for the linear-track conveyor system they use an approximate model that is a QAP. A heuristic method for the facilities layout problem is specialized to solve these problems. Computational testing compares results obtained to optimal solutions where possible, and to results published in the literature for larger problems. The QAP approach, as implemented here, finds optimal or near-optimal solutions for smaller problems, and significantly improved solutions, as compared to published results, for larger problems.