Research On Inventory Of WIP Control In Discrete Manufacturing System Based On Bottleneck Analysis

A lot of discrete manufacturing companies which are oriented by orders have too much inventory of work in process(WIP).And overfull inventory of WIP will bring high cost,long cycle time,and many problems such as quality problems being nonsensed to the company. As we know, cost, quality and response speed are the most three important factors between company's competition.So research on optimizing and controlling the inventory of WIP effectively in discrete manufacturing companies become an issue that both academia and companies very care about.By learning the existing metheds of optimizing and controlling the inventory of WIP, the author discovered that most of the methods regard all the working procedure in the manufacturing system as same important, and rarely care about the bottleneck procedure in the system.But as we know, the bottleneck is the key factor in the manufactuing system.So this will make the system's control cost too high because of lack of control emphases, and also will weaken the effect of the system's improving. According to the theory of constraints (TOC), this paper put the emphasis of controlling the inventory of WIP in production system on the system's bottleneck, based on detecting the bottleneck in a manufacturing system effectively by adopting the method of computer simulation, the bottleneck-driving Push&Pull production control mode which combined advantages of the most three popular production management theories MRP II ,JIT and TOC is framed in order to reduce the inventory of WIP in the whole system,and assure the bootleneck's continuous production by setting a reasonable amount of the inventory of WIP before the bottleneck. And then, the bottleneck's frontal inventory of WIP feedforward and feedback integrated control model is constructed, to make sure the inventory of WIP before the bottleneck can lever off at the initialization.In the end, an example of a product's manufacturing system in Anhui TongDu Valves Ltd. is given to testify the validity of the method and the model in this paper. A satisfying result is obtained by the computer simulation analysis.