Research And Application Of Production Planning Method For MTO-based Cold-rolled Sheet Enterprises

In this dissertation, the state of batch and production planning is reviewed and the characters of the cold rolling production system are also summarized in cold rolling enterprises. Taking a cold rolling production line of national certain Iron and steel enterprise as study object, batch and production planning problems of cold rolling are solved by considering the actual production situation in cold rolling enterprises. This dissertation has mainly carried on the following research.(1) Nowadays, one of the most important challenges faced by cold-rolling mills industries is the adjustment of the production mode in order to satisfy market requirements subjected to fluctuations over time, mainly product varieties, demands, etc. To do so, we propose a batch planning model including three objectives, which are(i) to minimize the difference of delivery,(ii)to minimize the difference of process route, and(iii) to minimize adjustment times of mills of all the batches while meeting the requirements of process constraints such as weight, width of outlet(inlet), thickness of outlet(inlet), and tensile strength. And then a fuzzy clustering algorithm based on the particle swarm optimization which is used to solve the model is established.(2) Cold rolling production process is characterized as multi-stage inventory and multi-flow directions. This paper presents a production planning model. The model meets process constraints,minimizing the total penalties caused by undue or overdue contracts, sufficient or insufficient intermediate inventory, and guaranteeing the minimum inventory costs of finished products.Genetic algorithm is improved by setting reasonable parameters to avoid the occurrences where crossover probability and mutation probability take fixed values within a certain range and the function values appear big jumps at some breakpoints or are unreasonable. These two probabilities can be adjusted adaptively by the fitness of individuals.(3) In order to make the presented model and algorithm to get the promotion and application,developing a contract production system of cold rolling sheet based on B/S model of J2 EE. This system can provide guidance for production in cold rolling sheet enterprises. Therefore, it will improve the management level for cold rolling enterprises.The formulated mathematical models and the corresponding algorithms for production planning and batch are tested by practical data. The numerical analysis has shown that the proposed model and algorithm are feasible and effective.