Implementing new dispatching rules at SGS-Thomson microelectronics

This paper reports a real-life manufacturing case study in the short term p roduction planning and control for a very large scale integrated (VLSI) cir cuit manufacturing production unit Dispatching in VLSI manufacturing is a crucial issue, since often binding c onstraints are set on the delivery dates by the customers downstream in the supply chain, while manufacturers, due to the huge fixed cost of capital g oods, must ensure the full utilization of their shop floors. The complexity of the manufacturing technology and the re-entrant nature of the resulting production flows further add difficulties to the problem. Starting from a shop floor scheduling based on simple dispatching rules, e. g. FIFO rule, or the well-known 'minimum set-up' criterion, workcentres hav e been firstly grouped according to their nature, then they have been class ified according to their criticality in terms of production capacity and fl exibility. Finally, for each class, a customized, yet suitable to be implem ented, dispatching rule is proposed and tested through a wide simulation ca mpaign. Experimental results show that the proposed dispatching approach le ads to a superior overall output and, at the same time, to an increased del ivery timeliness.