Research On JIT Theory And Optimization For Production Plan

Production plan aims to reduce inventory, improve resource utilization, to shorten themanufacturing time through reasonable planning on resources and logistics, so as to make theenterprise to produce by low cost and high efficiency. The traditional production plan is basedon MRPII. In the production of many varieties, small batch and short shipment, the shortage ofMRPII on the production plan’s execution is restricting the development of the enterprise. Inorder to reduce material inventory and order delivery rate, the paper is proposing a productionplanning model which mixed MRPII and JIT with the support of JIT theory and analysis on theproduction planning model of a discrete manufacturing enterprise. The paper focuses oninventory control model of JIT purchasing and equalization of JIT production in the MRPII/JITproduction planning model. The main content of this paper are as follows:In the1stchapter, in view of the shortage of production planning model in the productionof many varieties, small batch, short delivery, a concept of MRPII/JIT production planningmodel, which is fit the production mode of make to order is proposed. To research contents, theresearch status about theory of JIT purchasing and equalization of JIT production are introducedbriefly. Then the research method and content are presented.In the2ndchapter,the advantages and disadvantages of MRPII and JIT production planningmodels are addressed firstly. It provides the theoretical foundation for building MRPII/JITproduction planning model in the3rdchapter, JIT purchasing inventory control in the4thchapterand equalization of JIT production in5thchapter.In the3rdchapter, the production planning model of a discrete manufacturing enterprise isbecame the research object. After analyzing the production plan’s implementation, inventoryand the status quo of the value stream, the MRPII/JIT production planning model andimplementation steps are put forward, with the JIT theory introduced into the originalproduction plan model. This model’s difficulty is the control of JIT on the material procurementand production operationIn the4thchapter, the ABC classification of raw materials is introduced firstly. To problemof large class of A materials inventory, a JIT inventory control model which is based on theminimum cost of purchaser and supplier is established. The model is made up of supplier’s inventory cost, extension cost and purchasers’ out of stock cost, inventory cost, ordering costand product cost. It assumes that the time to finish the orders obeys exponential distribution andthe demand for raw materials obeys normal distribution. After solving the model, get thepurchasing quantity, order point and safety stock function. Finally, the feasibility of the model isverified through workshop instance.In the5thchapter, it introduces the quantitative timing mode of production scheduling. Tothe problem of low order delivery rate, a method of determine the bottleneck process inproduction order is brought forward. To the optimization problem of production sequence insome equipments of bottleneck process, in order to maximize utilization rate of equipment, theNEH algorithm is applied. Then uses FlexSim to simulate for he original production order andOptimization order by NEH algorithm and verifies the effectiveness of the algorithm.In the6thchapter, it summaries achievements and innovations of this dissertation, andprospects the future work.