Scheduling and simulated annealing application to a semiconductor circuit fabrication plant

Abstract

This paper addresses the scheduling problem of the input order of multiproduct batch processing systems. This type of plant configuration is typically used in the production of paints, medicines, cosmetics, electronics componants, etc. In a general way, the scheduling problem of large multiproduct batch plants (MPBP) cannot be solved exactly because its dimension is very high (problem NP-complete). An optimization technique called Simulated Annealing (SA) has already been successfully used to solve several large combinatorial problems ( for example, travelling salesman), and so we have implemented a SA methodology for determining the input order of a given set of products so as to minimize the average residence time of these products in the plant with unlimited intermediate storage (UIS) policy. The discrete simulation program developped in a previous part of this study is used to determine the value of the objective function. The proposed technique is applied to a real world problem - a semiconductor circuit fabrication plant of MOTOROLA Inc. (Toulouse) -.