Browsing by Author "Yang, C. J."

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The evaluation of search range assignment in 300 mm automated material handling system (AMHS)
(2008-01-01)
Sha, D. Y.
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Lin, J. T.
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Yang, C. J.
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工業工程與管理學系
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Department of Industrial Engineering and Management
In the 300 mm AMHS with a connected loops layout, the vehicle can travel not just in one loop but all around the wide fab to execute tool-to-tool delivery. Determining how far the waiting FOUPs (WFs) or idle vehicles (IVs) should be considered before selecting a dispatching rule might make dispatching more efficient. A two-phase approach with simulation has been developed to assign the search range (SR) for studying this idea. The model of a simplified 300 mm AMHS was built using eM-Plant and Design Expert to design experiments and analyse the results. In phase I, the number of WF and IV in the system at the time of dispatching will affect the distance of the vehicle's empty trip (DVemp). Further, the SR was assigned and evaluated based on the average and standard deviation of DVemp under different numbers of WF and IV in phase II. The results indicated that the SR significantly affects the performance, and a longer SR used in a light system is feasible; a shorter SR is applicable for a heavy system.
The transport strategies for fully automated manufacturing in 300 mm wafer fab
(2009)
Sha, D. Y.
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Yang, C. J.
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工業工程與管理學系
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Department of Industrial Engineering and Management
This paper addresses the operational issues of transport strategies in tool and vehicle dispatching integration (TVDI) architecture in a fully automated manufacturing wafer fab. At present, there are three transport strategies involved in vehicle dispatching, namely, avoid blocking, avoid starvation, and accelerate batch preparation. These strategies were developed to obviate production obstacles and to avoid capacity loss. Consequently, there are five levels in the decision-making process of TVDI, namely, dispatching request, conditions checking, candidate selection, dispatching rules, and result execution. Specifically, candidate selection was classified into five categories: FOUP-selects-tool (FST), FOUP-selects-stocker (FSS), tool-selects-FOUP (TSF), FOUP-selects-vehicle (FSV), and vehicle-selects-FOUP (VSF). The proposed transport strategies were implemented in VSF, and a simulation model abstracted from a wafer fab in Taiwan was used to evaluate the performance. The results show that the differences in the proposed strategies compared with ignoring the issues are statistically significant, and the performances of the wafer output, cycle time and waiting time can be improved.