考慮回收機制下再生物料混合比例之最佳生產模式

An Optimal Stochastic Model for Recycled Material Blending Manufacturing under Resources Recycle Fee and Subsidy Mechanisms

李思漢(Ssu-Han Lee)

指導教授 ： 蔣明晃 ； 郭瑞祥

國立臺灣大學/管理學院/商學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00377

摘要

近年來企業開始將逆向物流的概念納入營運作業模式中，不僅因應世界環保的趨勢，逆向物流可以讓企業從中獲得競爭力，如降低成本、提升企業形象等。當企業開始考量逆向物流的營運後，大都會採用再生物料(recycled material)進行生產，但使用再生物料為原料時常會加入原始物料(virgin material)混合生產，以增加物料特性的強度來符合標準，而廠商的製造設備也會因為物料混合比例的不同，使得設定的最佳參數也不同，製造設備的設定往往在短時間內無法任意的更改，再加上回收物料在回收的時間、數量以及品質上的具有高度不確定性，所以逆向物流的決策者希望對於這些不確定性能夠較為不敏感，因此本研究將要探討在某期間內再生物料的混合生產中，如何找出具強健性的最佳混合比例，以符合實際上的需求。
本研究探討混合比例的建置，同時參考國內費率制度的相關文獻，企圖建構出一個在資源回收回收體系下的混合再生物料製造商，以成本最小化的觀點，設計出隨機非線性規劃模型，且使用具強健性的隨機規劃方法進行求解，並設計隨機情境，以瞭解產品需求量、再生物料回收量、再生物料價格等不確定性，在不同費率結構下，對於製造商的再生物料混合比例決策及總成本的影響。

透過本研究可以得知製造商總成本會受到需求量變異、回收量變異、費率結構及物料價差的影響，而再生價格變異則會改變費率結構以及回收量變異對於總成本的影響。另外，再生物料混合比例會因為回收量變異、再生價格變異、物料價差及費率的不同而有所影響。因此就再生物料混合比例的決策而言，製造商在面對平均價格較低的再生物料時，並不會一昧的採用最高比例的混合再生物料的生產方式，會依照再生物料回收量、市場價格波動幅度的影響，選擇最佳使用再生物料的混合比例。費率結構對廠商而言，不僅影響製造商再生物料的混合比例的選擇、製造商生產成本的高低，甚至還影響製造商生產成本的性質，因此政府在制訂費率結構的時候，必須審慎的考量政策制訂的目標是否能有效的達到目標，及對製造商成本上的衝擊。

關鍵字

逆物流 ； 再製造 ； 線性規劃 ； 資源回收 ； 二次料 ； 強健性 ； 混煉

並列摘要

In recent years, enterprises began to apply the concept of the reverse logistics to their business model to obtain competitiveness, such as lowering costs or improving the corporate image. More specifically, enterprises may add in recycled materials while manufacturing their products. By blending recycled materials with virgin materials, the firm needs to determine the best setting parameters for manufacture equipment when the blending proportion changes such that the intensity of mixed material to produce can be increased. But because the equipment settings are not allowed to be changed frequently and there exists high uncertainty of recycled material both in quantity and quality, the policymaker of the reverse logistics wants to search a manufacturing decision which can be less sensitive to the uncertainty. Thus, in this research, we will base on the concept of robust to determine the optimal blending proportion to manufacture between recycled material and virgin material, and also examine how the related parameters affect a firm’s manufacturing cost.

First of all, a multi-period stochastic non-linear programming model is constructed based on past researches about recycled material blending problems and current fee and subsidy structure in Taiwan. We develop a stochastic programming method to solve it. Moreover, experimental design associated with scenario planning is used to analyze how blending proportion and total manufacturing cost are affected by different variations from product demand, availability of recycled materials, difference between recycled material and virgin material cost, and two different fee and subsidy structures.

From the results of analysis, we find that product demand, availability of recycled materials, difference between recycled and virgin material cost, and fee and subsidy structures have significant impact on total manufacturing cost, while the spot market price of recycled materials could make a different impact of availability of recycled material and fee and subsidy structure on total manufacturing cost. Speaking of the blending proportion, the manufacturer will readjust the proportion as product availability of recycled materials, spot market price of recycled materials, difference between recycled and virgin material costs and fee and subsidy structure change respectively. We also observe that the fee and subsidy structure plays an important role in determining not only the best proportion mix but also manufacturing expense in each period. Thus, Recycle Management Fund must take all factors into consideration so as to make sure that the fee and subsidy structure could achieve the goal Government wants.

並列關鍵字

reverse logistics ； remanufacturing ； non-linear programming ； recycled material ； robust ； blending

參考文獻

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