Study And Application Of The Production Planning Management System Based On JIT In The Multi-varieties And Small-batch Environment

With the increasing market competition and the diversification of user needs, the production model of multi-varieties and small-batch is becoming the mainstream. In this model, product's variety, small-batch, low repetition and process route's frequent change make the production planning more difficult. Chongqing Wangjiang Co.Ltd is a typical multi-varieties and small-batch business. Through analysis of the company's current production situation, a new production planning model based on JIT is proposed in this paper. And a production planning management system is developed based on this model. The main research contents are as follows:Firstly, this paper analyses the theory and current research of JIT, and the practical significance of JIT is proposed for enterprises production. Secondly, the company's current production planning system was researched and the problems and shortcomings in the production process are also analyzed under this system. Then, a new production planning system based on JIT is proposed. It consists of three levels of production plans, that is, the upper level plans, the middle level plans and the lower level plans. Among them, the middle level plan is the focus of this system, and it consists of Master Production Planning (including machining plan and procedure plan), Material Requirements Planning (including roughcast plan) and Capacity Requirements Planning. The system's basic idea is taking the product's deadline as the "source of pull" of JIT, combining the meta-knowledge library of product, pushing down the latest completion time of each accessory from the root of the product and layer by layer, resulting in the corresponding Master Production Planning and Material Requirements Planning. Then, the Capacity Requirements Planning is made to determine whether the current production capacity can meet the needs of production planning. Thirdly, the system is designed in detail from the system's physical architecture, technical architecture, function modules and database aspects. Last but not least, an instance of the system and summary of research work and achievement are given, and the suggestions and ideas are proposed for the future research.The system has been put into use in Chongqing Wangjiang Co.Ltd. And it has achieved good effect and the desired goals.