Optimization of due-date objectives in scheduling semiconductor batch manufacturing

This paper presents look-ahead batch scheduling for the real-time control of due-date objectives, such as average tardiness, maximum tardiness, and number of tardy jobs in batch processes. These due-date objectives play an important role in several production industries such as semiconductor manufacturing, aircraft industry, metalworking industry, etc. In look-ahead batching, the scheduling decisions are based on the arrival epochs and due-dates of incoming lots at each work station which are easily predictable in a computer integrated manufacturing environment. The steady state performance of the developed control strategy is compared to the steady state performance of the theoretically optimal control strategy (i.e. a Minimum Batch Size strategy). The experimental results indicate that the developed look-ahead batch scheduling strategy improves the performance of due-date objectives under wide conditions of arrival pattern, due-date distribution and traffic intensity.