Research On Method And Information System For Flexible Job Shop Scheduling Based On BOM

With the increasingly open of the global market, customers' demands become increasingly diversified and personalized. Meanwhile the market condition as well as manufacture environment that the enterprises faced with have undergone fundamental changes. Thus the mode of production management transformed gradually from extensive management to intensive management. Companies must insist on customer-oriented, not only meet customers' individual demand but also meet customers' due date. So as to strive to survive in the transitions. Therefore, how to achieve delivery just in time and continuously improve customers' satisfaction and loyalty have become the theme for the companies to stand in an invincible position.Job shop scheduling(JSP) study is to optimize the allocation of productive resources under its corresponding constraints so as to make one or several indicators of production system(maximum completion time of jobs, production costs, the total tardiness of jobs, etc.) be the best. JSP is one of the most complicated NP-Complete combinatorial optimization problems. Flexible Job shop scheduling(FJSP) is more complex. After decades of development, Scholars at home and abroad had put forward a lot of methods to solve the problem. These methods were be used in the actual production process, however, the effect is not satisfactory.In the paper, a flexible job shop scheduling method based on BOM is proposed against the deficiency produced by the traditional flexible job shop scheduling in the actual production process. Firstly, taking the workshop calendar of equipments into account, with the minimized tardiness as the optimization objective, a flexible job shop scheduling model based on BOM relationship between the jobs is constructed. The improved genetic algorithm is applied to get the optimized scheduling scheme set. An example simulation is given to demonstrate the efficiency of the proposed method.Secondly, on the one hand, when the minimum total tardiness equals zero, all the optimized scheduling schemes meeting the due date are output. Then these schemes' proportionality and robustness are further considered. Then the optimal scheduling scheme is obtained to improve the noise immunity of the scheduling scheme and instruct enterprises to produce in a balanced and ordered manner. On the other hand, if there is tardiness in the optimized scheduling schemes, the batch processing mode is used to obtain the scheduling schemes meeting the due date. Then these schemes' proportionality and robustness are further considered.Thirdly, Most of the traditional job shop scheduling studies focus on the static scheduling problem. In practice, however, the production system is not immutable. There are a lot of random interference events in the actual production system, such as production equipment failure, emergency orders and process delay. When these unexpected events occurs, the pre-scheduling scheme might not be able to continue and must be rescheduled. Based on the production practice, the traditional job shop scheduling problem is extended. Combined with the existing research results of dynamic scheduling and the mentioned method in this paper, a flexible job shop dynamic scheduling method based on BOM is proposed. And the effectiveness, feasibility and stability of this method are verified by production example simulation.Finally, based on the above mentioned research, a decision support information system of flexible job shop scheduling based on BOM is designed and developed. The system includes three basic functions, namely, scheduling data management, preliminary optimal scheduling and comprehensive evaluation decision. Good application effect is achieved when this system is tested in a machine shop.