Conceptual framework for lot-sizing and scheduling of flexible flow lines

The paper considers the lot-sizing and scheduling problem for flexible flow line production facilities. Flexible flow lines are flow lines with parallel machines on some or all production stages. The objective is to find lot-sizes and a feasible schedule that minimizes set-up, inventory holding and back-order costs. Minimization of mean flow time (measured between entering the first stage and leaving the last) is a secondary objective. An integrative solution approach is presented that can incorporate the interdependencies between lot-sizing and scheduling decisions. Applications of the approach in the semiconductor industry are illustrated.