| Summary: | 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.
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