Research On Continuous-time Batch Production Scheduling And It's Application

Printing and Dyeing industry, an important component of the manufacturing industry of China, is a typical chemical batch process. Its production line is complicated and has a lot of character, such as large amount of product kinds, flexible production equipments, changeful product kinds and so on. As the core process of Printing and Dyeing production, dye-vat production scheduling is complex, and most of Printing and Dyeing enterprises still rely on artificial arrangements of dye-vat production, which lead it to be the choke point of the development of Printing and Dyeing enterprises. Therefore, a rational production scheduling method, which improve the production efficiency and reduce their production costs, can significantly improve the situation of Printing and Dyeing enterprises.This study introduces the theory of the scheduling, and various methods of batch scheduling. Then, under the background of production process management system in Zhejiang Mizuda printing and dyeing Group, a continuous-time MILP mathematical model of production process scheduling based on immediate batch precedence is presented, and this model with production data was solved by ILOG OPL Studio. The computational result was shown in Gantt diagram, which indicates the results are effective. The major contents of this paper are described as follows:1. Introduced the basic concepts and developmental status of the production scheduling at first, and then a brief introduction of the developmental status and concepts which relevant to the batch scheduling has been given.2. In this section, we introduced the specific process and the characteristics of Printing and Dyeing production at first, and then put the objective of Printing and Dyeing production scheduling forward. According to process of dye, the core process in Dyeing and Printing production, a continuous-time MILP mathematical model of production process scheduling based on immediate batch precedence is established by directly handling the scheduling order of dye-vats as the decision variables for the optimization objective function, which meets printing and dyeing production demand. The model, the objective of which is to meet the orders'delivery date and minimize the circulation time(or maximize the completion time),is fully considers the actual situation of the production in dye process, such as multi-related o rders, multi-product and switching costs related sequence and equipment.3. The continuous-time MILP mathematical model of production process scheduling based on immediate batch precedence is formulated and implemented in ILOG OPL Studio, which based on established production scheduling models that meeting Printing and Dyeing production demand. Besides, actual example was presented in this paper to be modeled and realized in ILOG OPL Studio. Analysis the computational results and Gantt diagram of the example to verify the validity and feasibility of the continuous-time MILP mathematical model of production process scheduling.Finally, some problems for further research are pointed out, based on a summarization of this dissertation.