Research On Production Planning And Control In The Automotive Mixed-model Assembly Lines

Mixed assembly is a way to produce multi-species product with higher productivity. This new production mode is now adopted by more and more enterprises.And research on production sequencing, which is most important to this production mode, has become a research hotspot. This mode involves of different product, complicated assembly process and a wide variety of materials.Therefore controlling and planning of this mode is more complex than the general assembly production.In this paper, with empirical and normative research methods, a number of key issues in mixed assembly production are studied.First, related works on production sequencing and controlling of mixed assembly mode are reviewed. Second, production plan on mixed assembly of the car has been studied. It includes researches on the framework of production planning, sequencing in automobile mixed assembly line and the objectives of the sequencing of mixed-model production. Evaluation index system on production plan in automobile mixed assembly line is set up.And with the methods of analytic hierarchy process (AHP),production plan in automobile mixed assembly line is evaluated. At last, production control about automobile mixed-model assembly is research. It includes dynamic production scheduling, dynamic management of the work-in-process products, dynamic control of the progress of production and dynamic control of the delivery of production assembly parts.According to the actual needs of the automotive industry, four components distribution methods are used, and a distribution pattern based time and quantitative is proposed.Through the above study,the results and conclusions are as follows:First, seven optimization objectives of mixed-model production are summed up, that is production time, equipment load, daily production line load, production line adjustments in mixed-model cycle, production line adjustments in enterprise operation, the cost of raw materials, the bullwhip effect between the processes in production line. These goals have been analyzed, and evaluation index system of automobile production plan has been set up.Second, three mixed production programs are proposed. With an AHP model,three mixed production sequencing scheme are evaluated,and an optimal plan is chosen. This method can also be used to determine more complex schemes.Third, through the research of production process, some methods to control mixed assembly line are presented as follows:(1)In order to cope with change of orders, an order control system which is flexible and stable is established. A double module scheduling methods is proposed. It is that the pre-scheduling module and scheduling module are established, and the orders in the scheduling modules will be scheduling for the production according to certain rules of the rolling, so if the order changes, it only needs to change orders in pre-scheduling module. Through this work,a real-time dynamic rolling order control mechanisms is set up,and program flexibility is improved.(2)The dynamic idea is used to manage the work-in-process products. With the product ID, dynamic tracking and backtracking is available.(3)To control the progress of the production work, an method to monitor product amount and production process is proposed.(4)The mixed-model production also makes higher demands to the delivery of components.Based on the analysis of the normal distribution of components, the complementary approaches and the components matching system, a distribution pattern based time and quantitative is proposed.