ANALYSIS OF DISPATCHING RULES FOR JOB SHOP SCHEDULING IN A - DYNAMIC ENVIRONMENT

Abstract

The present day manufacturing industries consist of complex systems and apply various approaches to make best use of the available resources. In this regard production planning and control activities play an important role and ensure effective conversion of raw material into finished goods in such a way that high productivity goals are reached. Scheduling is the most important activity of production control determining the effective flow of inventory from raw material stage to end product. Even though Flexible Manufacturing Systems, Cellular Manufacturing and Computer Integrated Manufacturing represent the key .trends in the modern job shop and batch production, the job shop continues to be relevant till date for production of a vast range of products, and in repair and service shops. Dynamic job shop scheduling problem exist in most of the advanced manufacturing systems in different forms. In a dynamic job shop environment there will be certain amount of uncertainty about the arrival of jobs for which application of heuristics are found to be suitable rather than analytical approaches. There is a need to study the performance of various heuristics under different conditions for the dynamic job shop. The present work is formulated to study the performance of some commonly used heuristics for dynamic job shop problem considering the different arrival patterns. A simulation program is developed in C++ language and the different heuristics are compared using performance criteria as Average job tardiness, % of job tardy, Average job time in the system and Maximum tardiness. III