The Study of Controlling the Dynamic Work-in-Process Level for Wafer Fabrication Factories

• Main Authors: Kang, He-Yau, 康鶴耀
• Other Authors: Shu-Hsing Chung
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/96042139061680518357

碩士 === 國立交通大學 === 工業工程與管理學系 === 85 === The wafer fabrication industry in Taiwan has the most competitive advantage. To keep the competitive superiority, each firm devotes to production planning and control. The goals of production planning and control include reducing WIP level and production cycle time, increasing due date performance and throughput. The objective of this research is to study the effect of four modified models on the actual WIP distribution. Buffer management and machine breakdown are taken into consideration in our study. The four modified models are CONWIP/ FIFO, CONWIP/SPT, CONWIP/replying the Machine-Breakdown and modified TB+. We apply the idea of Taguchi method to design WIP Production Flow Control（WIPPFC）chart and WIP Control Capability Index（Cwip） for evaluating the performance of these models on the WIP level. The modified TB+ is more complicated due to the control of the throughput and WIP of each layer. However , the results of simulation show it has advantages of stabilizing the throughput and leveling the WIP of each layer. CONWIP/replying the Machine-Breakdown adjusts the WIP level when the machines break down. The simulation results show that it can lower down the WIP level but does not have significant effect on increasing the throughput. The other two methods, CONWIP/FIFO and CONWIP/SPT, just control the system throughput and the system WIP level; they do not control the throughput and WIP of each layer. However, CONWIP/SPT can lower down the maximum utilization rate of the buffer before each workstation . Through this research, modified TB+ method with WIP management and WIP production flow control is found to be useful and efficient in controlling the variation and distribution of WIP and in increase the system performance.