結合良率與成本分析評選多重供應商

Multiple Supplier Selections Based on Yield and Costs

湯寬傑(Kuan-Chieh Tang)

指導教授 ： 林真如

元智大學/工程學院/工業工程與管理學系/碩士(2011年)

https://doi.org/10.6838/YZU.2011.00004

摘要

一般產品製造商的原材料採購，會因為品質穩定，而一直使用同一家供應商所提供的材料。若供應商提供的材料品質逐漸低落，導致製造商生產良率因而下降，便會啟動另尋材料供應商的機制。或是當製造商希冀降低材料成本時，便會考量替換材料。又如供應商的產出能力無法滿足需求量時，便容易產生缺料問題，導致客戶納期的延誤，此時製造商亦需另外找尋符合標準的供應商。以上為採用單一或多家供應商政策下可能面臨的問題，由此可見，如何在成本考量下，評估材料的品質，為供應商選擇的重要問題。
評估多家材料供應商時，一般計算不良品個數的方法並不有效率。尤其當材料的良率極高，則可能無法做出有效判斷。所以本研究以製程良率指標Spk及多重比較Dunn-Sidak 法為基礎，利用檢定兩兩供應商良率之間的差異，提供選擇多家供應商時的依據。在比較良率差異幅度後，本研究將材料成本納入考慮，分析具備較高良率的供應商所提出之材料價格是否合宜，以尋求品質、價格均佳的供應商。如果能從多家供應商中評估條件最好的供應商，或是挑選兩家以上適合
的材料供應商，不僅可以保持供貨的穩定，還可創造出日後議價的空間。最後本論文以被動元件廠做為案例，在品質及材料成本的考量下，運用本研究所提出之方法，找出最符合需求的供應商。

關鍵字

供應商選擇 ； 製程能力指標 ； 多重比較方法 ； 成本分析

並列摘要

A manufacturer tends to purchase raw materials from the same supplier if the quality remains stable. Suppose that the production yield rate decreases due to the low quality of raw materials. The manufacturer will initiate a project to look for new suppliers. If a manufacturer plans to reduce material costs, the company may consider replacing materials. When the supplier cannot fulfill demand, the manufacturer will search for other suppliers. Otherwise,
the due date will be delayed due to lacking of raw materials. These are common problems under a signal or multiple suppliers. Thus, supplier selection under the consideration of costs and quality is an important issue.
Counting the number of defectives is inefficient in evaluating suppliers, especially when yield rate is high. Therefore, this research tests the difference between two yields from any pair of suppliers by using Spk index and Dunn-Sidak based method. The impact of cost will also be taken into account during the analysis. The goal is to identify the best suppliers in terms of quality and price. If a manufacture can select two or more best suppliers, the
company not only can have stable supply, but also can have chances to negotiate price in the future. Finally, this thesis investigates a case study in passive device and applies the proposed method to find the best suppliers.

並列關鍵字

supplier selection ； process capability indices ； multiple comparisons ； cost analysis

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