MULTI CRITERIA DYNAMIC SCHEDULING WITH MACHINE BREAKDOWNS

Abstract

Increasing demand for new products creates the need for production systems that are flexible and allow shorter product life cycle, smaller production lots, large variety and ensure 100% on-time delivery. Nowadays manufacturing is characterized by a consumer-oriented market giving more options and choices to the consumers. Hence, the significant trends in the present day market oriented manufacturing are large product variety and frequent design changes, which translate into low production volumes. Low quantity, high variety, small batch production requires a manufacturing system with a reasonably high flexibility not only in manufacturing equipments but also in design, planning and , decision making. A rapid and timely response to market demands is the key to achieve high competitiveness. These challenges set the new trends in evolution of modem manufacturing systems that are increasingly becoming more complex. In these systems, planning and scheduling functions need to be addressed with much greater rigour and precision in order to achieve their effective utilization in terms of productivity. Production planning and control is a very complex process, which lies at the heart of operations for manufacturing companies. In increasingly competitive consumer driven markets, which prevail in most manufacturing sectors, the successful operation of production planning and control systems is essential to the survival of manufacturing organizations. Nowadays, companies operate in a much more dynamic mode, characterized by greatly reduced life cycles, greater product complexity and enhance capability to supply in a short time and introduce new product ranges very rapidly. Traditionally, scheduling research was concentrated on small size systems with exact solution procedures based on assumptions that are far removed from real systems. Such solutions of the scheduling problem are essentially theoretical in nature. To bridge the gap between theory and practice it is necessary to consider practical factors such as availability of alternate process plans, multiple performance measures, dynamic arrival of jobs and machine availability constraint.