Research Of Multiple Stage Complex MES System Production Scheduling Algorithm And Its Application

In the semiconductor,integrated circuit,TFT-LCD panel and other complexmanufacturing processes, products require multiple processing stages, and often a variety ofproducts are manufactured at the same time,with batch processing, and parts assemblyprocessing in the process, the whole production types are mixed flow.. Because equipments ofthis kind of production system is very expensive,so how to arrange the production plan andscheduling, ensuring the production process to be completed as soon as possible under thelimited equipment and resources condition, t determines the enterprise whether can get a placein the fierce market competition. But due to various production process equipment, complexprocess, and processing mode diversification, find a reasonable and effective way ofscheduling becomes a difficult point.From the perspective of resources of such production enterprises,a method ofmanufacturing resources management int the aspect of the meta model is proposed.The modelof the production process is build and analyzed and the bottleneck resource of the wholeproduction system which determin the system productivity is recognized.For the problem ofbottleneck resource utilization,the theory of constraint is used to make reasonable schedulingof the workpiece on the bottleneck workstations and equipments.The main research work is as following:(1) The management methods of the core manufacturing resources which are related tothe production scheduling is researched, a manufacturing resource meta-model is establishedand a kind of manufacturing resources management framework based on meta-resources isproposed. different patterns of meta-model and the conversion algorithm from databaseschema to XML schema and object description schema is researched in this article.(2) The basic method of using the theory of constraints is used to identify the bottlenecksand set buffer,togother with the job scheduling in the multi-phase complex production processis researched the difficulties and problems of DBR technology in the process ofimplementation.is analyzed from three aspects:drum, buffer and rope. (3) Mathematical modeling is carried out on the production scheduling process.Theconstraints in the process of scheduling and the scheduling goal is analyzed. A representationmethod based on production process tree is put forward for the assembly job,and the conceptof key processing route and key components is introduced combining with the bottleneckresources The mathematical equation of constraints and scheduling objectives is built basedon the detailed mathematical description of each key parameters in the process of scheduling.(4) The application of DBR implementation technology in the scheduling process isanalyzed in detail,workload calculation method under the probability distribution is ofproposed and verifyed by Plant Simulation.Bottleneck recognizing is assisted by usingsimulation software.Bottleneck workstation scheduling algorithm under given parameters isdesigned. Genetic algorithm is used to optimize parameters such as buffer coefficient,transportation quantity and sorting rules.TFT-LCD Cell process is used to verify the methodas an example.Production scheduling prototype system facing this type of production workshop iscreated based on the above research work,and the the system is researched from four differentlevels of requirements analysis, system architecture, database and object design and systemimplementation. The effect of the system implementation is analyzed at last.