以系統模擬探討流程式生產的顧客訂單分歧點之設置

A Study on Positioning CODP of a Flow Shop with Simulation Method

邱于峮(Yu-Jiun Chiou)

指導教授 ： 項衛中

中原大學/工學院/工業工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200469

摘要

由於半導體市場受到全球化影響，台灣半導體設備廠的客戶群越來越廣泛及多樣化。設備廠產品客製化的種類也越來越多，使得產品銷售預測的準確性越來越低。當設備廠產品預測發生錯誤時，通常採取將預測錯誤的產品拆卸重工，雖然此方法需要負擔額外的拆卸與重組的費用，但可有效的縮短產品製造時間與出貨時間。
本研究參考半導體設備廠的生產流程並將其簡化成含有四個工作站的流程式生產，並設定每一個工作站都需進行零組件的組裝。本論文探討在拆卸與不拆卸的決策下，五個顧客訂單分歧點的設置位置對於總成本所造成的影響，並且以模擬的方式來計算相關數值。本論文以顧客訂單分歧點、拆卸站別、拆卸個數、人員配置與兩訂單單位遲交成本比例等五個因子做為自變數，以總成本為應變數，分別針對拆卸與不拆卸的決策進行實驗設計，並從結果發現此五種因子在拆卸與不拆卸的情況下均為顯著。
本論文在拆卸與不拆卸兩種決策中，挑選出最佳顧客訂單分歧點之設置位置，做為降低半導體設備廠總成本之建議。本論文認為在拆卸決策中，顧客訂單分歧點設置於第二站之後較佳，主因是第二站為半導體設備廠的瓶頸作業站，如此可以縮短生產平均時間。然而在不拆卸的決策中，顧客訂單分歧點設置於最後一站為最佳。因本研究假設正確預測實際訂單，當實際訂單到來時，可將完工之產品直接出貨，以達成降低成本、提高顧客滿意度之需求。

關鍵字

顧客訂單分歧點 ； 系統模擬 ； 流程式生產

並列摘要

Semiconductor market is highly affected by globalization, and the requirements of equipment products become very diverse. Therefore, it is harder and harder to have accurate sales forecast for customized equipment products.
While forecasting errors happened, such as the forecasting number was not correct or excess demand occurred, the manufacturer would consider work-in-process (WIP) of the similar products in the plant. Sometimes, regular order with similar components will be disassembled to fulfill the rush order. Although the rush order can be delivered on time in this way, the regular order might become late and the total production cost would increase.
In this study, to solve inaccurate forecasting or excess demand problems, a simulation model was developed to calculate total cost with various customer order decoupling points (CODPs). The assembly process was modeled as a flow line with four consecutive workstations, and components were assembled or disassembled in each station. This model would decide whether to disassemble similar products to meet the customer requirements and to minimize the production cost with different CODPs.
Experimental design was applied to analyze the effect of independent variables on the total production cost. The independent variables are position of CODP, ratio of unit costs for tardiness, disassembling process, number of disassembled WIP, and operator number. Even experiments with disassembling WIP or not to disassemble were conducted separately; all independent variables were significant in either decision.
Based on the results and the response of each factor, this study suggests that the CODP should be placed after the second workstation for the disassembling WIP case. The main reason could be this arrangement would increase the utilization of the second station and decrease the cycle time since the second station is the bottleneck one. For the not-to-disassemble decision, this case became a make-to-stock production way. The main reason is this paper assumed the real regular order is as same as the forecasted one.

並列關鍵字

customer order decoupling point ； simulation ； flow shop

參考文獻

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