| Summary: | 碩士 === 國立交通大學 === 工業工程與管理系 === 90 === To achieve the high delivery and high profit target, it’s necessary for wafer fabrication to control the product cycle time effectively. Hence, this research estimates the product cycle time with applying the Block-Based Cycle Time Estimation with Multiple-Priority Orders (BBCT-MP), and the number of overhead hoist transporter (OHT) plan and the transportation time estimation proposed in this research.
This research proposed contains four modules. First, the aggregate plan (AP) module estimates the ideal number of OHT of the system to minimize the probability of production delay resulted from the OHT. Secondly, the master production schedule (MPS) module follows the number of OHT planned in the aggregate planning module, and analyzes the transportation time needed in each process step, compares the transportation time with the queuing time resulted by the loading factor or the batch factor in the order of process step to estimate the product cycle time of each priority and product. Thirdly, the detail schedule (DS) module makes the release rule with the batch-CONWIP release rule. Finally, the production activity control (PAC) module designs the vehicle management based on the concept of Minimum Inventory Variability Schedule (MIVS) in case the increase of product cycle time, and achieves a high on-time-delivery.
Simulation experiment reveals that on the premise of keeping the bottleneck machine utilization, even the layout or product mix changes, the number of OHT proposed in this module won’t make any OHT be a waste. Compare the estimated product cycle time and the simulation result, the average error is less than 3%, and the achievement of on-time-delivery is higher than 98%. Consequently, the module proposed in this research is effective and efficient, and can be a feasible reference of production plan on the consideration of transportation.
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