批量式生產/組裝系統最佳策略之研究

Optimum Inventory Policy on Batch Process and Assemble System

何怡潔(Yi-Chieh Ho)

指導教授 ： 蔡啟揚

元智大學/工程學院/工業工程與管理學系/碩士(2007年)

摘要

近年來面臨全球化資訊進步的影響，消費者對於科技產品之需求變化極為迅速，企業主將紛紛採用模組化的生產方式。所謂的模組化生產指的就是結合存貨式生產(MTS；Make To Stock)與接單式生產(MTO；Make To Order)兩種模式的生產方式，因模組化產品之複雜性與資源限制下，在存貨管理上將會變為更加複雜化。
本研究是針對多物項產品之二階層存貨系統，其二階層是由第一階層原物料存貨系統與第二階層半成品存貨系統所組成，而兩階層的存貨系統之存貨量具有相依關係，也就是說第二階層產品製造是提取第一階層原物料之存量而來；並認為在考量批量生產與批量訂單的因素下，因批量訂單會使得存貨一下子大幅度的下降，而批量生產則會使存貨量一下子增加許多，所以存貨量的震盪勢必會較激烈。因此本研究依據訂購量決策變化(EOQ、倍數與二冪)，並採用兩種決策法則(分散式決策法則與集中式決策法則)，以最小化二階層存貨系統總相關成本為目標，藉由程式搜尋找出最佳存貨策略。並觀察需求量變化與相關成本參數變化，對趨勢變動與整體總成本的影響。最後從結果比較發現集中式決策在不同需求狀況下能改善存貨系統的總成本，並得到最小化二階層總相關成本。

關鍵字

二階存貨系統 ； 訂購批量 ； (s, Q)存貨策略

並列摘要

In recent years, the impact of globalization and technical merchandises change very fast, therefore modular becomes the best method to produce. Modular means combined two modules which are Make To Stock and Make To Order, but it is complex and is limited by resources that will cause inventory management to become more and more complicated.
In the two phases of the inventory system which is consists of material on first stage and products on second stage, the quantity of inventory have dependent relationship. In other words, the manufacturing of products at the second stage needs the inventoried materials at the first stage. After that, we will consider batch to order and batch order, because first one will affect inventory to be decreased and other one will increase inventory a lot. The quantity of inventory will be dramatic influence.
Accordinging to quantity of order strategy(EOQ、multiple、Power-of-Two Policy)and two decision strategies (sequential strategy and coordinated strategy) are discussed when searching for the best inventory policy based on the minimum total cost of the two-echelon inventory system. Finally we can see that coordinated strategy improves total cost of inventory system in different conditions and get amount of cost between minimum the two stages.

並列關鍵字

Two-level inventory system ； batch to order ； (s, Q) inventory policy

參考文獻

9.黃建程，「兩階層配銷系統(R, S)存貨政策—倉儲中心與零售點具相異盤存週期之模式發展」，國立成功大學工業管理科學系，碩士論文，2002。

10.張瑜真，「考量多物項多產品下二階存貨策略之模擬研究」，元智大學工業工程與管理學系，碩士論文，2005。

18.Chen, F. and Y. S. Zheng, “Inventory models with general backorder costs,” European Journal of Operational Research, 65 (2), 175-186 (1994).

11.Axsater, S., “Simple evaluation of echelon stock (R, Q) policies for two-level inventory systems,” IIE Transactions, 29 (8), 661-669 (1997).

12.Axsater, S., “Scaling down multi-echelon inventory problems,” International Journal of Production Economics, 71, 255-261 (2001a).