The elements and functions of hierarchical scheduling system of order production

The purpose of this study is to develop a more flexible and effective scheduling system of order production which is adaptable to the dynamic fluctuation of customers’ demand and process capacity. In recent years the importance of developing an effective and flexible scheduling system in job production has increased in accordance with the diversification of customer demand and products. Many heuristic job shop schedling rules have been investigated by theoretical and experimental means in order to satisfy the aforementioned demands. On the other hand, expert systems and artificial intelligence have been introduced to job shop scheduling and complicated scheduling problems. Several expert systems are known to be more efficient, but it is not easy to adopt them for other scheduling problems because the structure and characteristics of their models are must too specialized. The basic concept of the hierarchical scheduling system and the function of subsystems are examined in this paper. A hierarchical scheduling system which includes the functions of order screening, loading and dispatching is proposed. As measures of scheduling performance of this mode, effectiveness of machine loading and tardiness beyond the specified due date are introduced. The developed hierarchical scheduling system is applied to an actual electronic parts manufacturer, thus the effectiveness of the system and the problems to be improved upon were clarified. The purpose of the study is to establish a basic model of an effective scheduling system of order production under market diversification, short production lead time and increasing market uncertainty. A scheduling model with hierarchical structure which includes the functions of screening, loading, and dispatching is proposed.