供應商代管庫存(Vendor Managed Inventory, VMI)模式，始於 80 年代中期 威名百貨(Wall-Mart)與寶僑(P&G)的合作。藉由供應鏈成員彼此之資訊分享與 協同合作，以 VMI 模式協助整體供應鏈降低成本、加快回應速度、提升營運 效益及客戶服務滿意度。緊固件(Fastener)為螺絲、螺帽、鉚釘等結合性零件 之泛稱，在存貨價值分類中屬於 C 類產品，其產品生命週期亦較長，適合實 施 VMI 模式。美國緊固件產業於 90 年代中期導入 VMI 模式，並於 97 年由台 灣緊固件業第一大出口貿易商:友信國際股份有限公司首先導入台灣。本研究以友信為研究個案，針對緊固件跨國供應鏈之企業動態經營模 式，做傳統客戶自管庫存模式(CMI)與 VMI 兩種管理模式之比較，並在各種 情境下下作模擬分析。首先是四種需求型態下，傳統安全庫存配置之模擬分 析。其次是梯狀突增需求下之最佳化庫存配置模擬分析。最後是不同客戶交 易條件下，供應商庫存最佳化配置模擬分析。 存貨與斷線為緊固件業經營上之兩大風險，存貨多寡直接反應成本增 減；缺料所造成客戶生產斷線不僅必須支付停產罰款更可能失去客戶。因此 本研究以存貨持有成本、存貨週轉率與訂單達成率為執行ＶＭＩ模式之關鍵 績效指標。模擬實驗結果顯示，由海外客戶及整體供應鏈之角度，VMI 供應 商代管庫存營運模式之營運績效均優於傳統模式，尤以海外客戶績效改善幅 度最為顯著。同時經由此模型之建構，亦能夠協助解決國內業界在 VMI 推廣 與缺乏風險評估的問題。

Vendor Management Inventory (VMI) is one of the most widely discussed partnering initiatives for improving multi-firm supply chain efficiency. Also known as continuing replenishment or supplier-managed inventory, VMI became popular in mid -1980’s, pioneered by the famous retailing case of Wall-Mart and Procter & Gamble. Through sharing inventory information and collaborating work in procurement, VMI allows suppliers manage inventories for their customers, thus streamlining the entire supply chain process and leading to cost reduction for the overall supply chain. VMI can apply to a product with large transaction volume and relatively long product life cycle, and the fastener industry falls into this category. VMI was first implemented in the fastener industry in the early to mid-90’s, and later was applied in Taiwan by QST International . Considering the system dynamic model of international fastner supply chain, a case study of QST was conducted in this article. The purpose is to compare VMI with the traditional inventory management practice. The comparison is based on simulation experiments in various scenario designs. By setting up a safety stock environment, this study first examined supply chain performance in four different demand patterns. Then the supply chain performance was assessed by simulating a precipitate demand increase. This study finally addressed the supply chain performance in different terms of transaction with overseas customers.Inventory cost and shut-down penalty are two major risks in fastener business operation. The amount of inventory has a direct influence on cost in the supply side. Material shortage will have customers shut down their production line, and suppliers in turn face penalty and loss of faith. Consequently , this article selects inventory cost, inventory turnover rate and order fulfillment rate as the key performance index (KPI) as the comparison criteria . The findings based on the simulation experiments indicated that optimum replenishment parameters of VMI model are established through scenarios design, dynamic simulation, parameters tuning and KPI measuring. Furthermore, a systematic modeling approach provides Fastener VMI players with feasible methodology in solving real world VMI problems.

供應商代管庫存模式(VMI)之核心觀念雖可簡化為資訊分享、協同運作，文獻中也不乏諸如Walmart及Dell實施VMI之成功案例。然而台灣實務界仍缺乏針對產業特性建構之VMI動態量化模型。以致實務界若非僅能由理論之觀點揣摩VMI模式之運作方式，便只能由其他產業之經驗自行摸索，造成VMI觀念推廣之困難。此外，由於缺乏效益與風險評估工具，無法精細評估VMI實施前後供應鏈成員之利益與風險，導致在與客戶及製造廠商議定價格與協商供應合約時，缺乏實證依據從而造成決策偏頗及困難。概念推廣與效益評估工具實為台灣實務界推行VMI之二大障礙。 本研究主要針對台灣緊固件業之產業特性，結合實務經驗與學術理論，採用系統動力學之方法，建立緊固件產業供應鏈之傳統客戶自管庫存模式(CMI)與VMI跨國動態量化模型，具體說明VMI模式與CMI模式之差異。並可依據個別企業實際運作條件，設定特殊參數，實際模擬個案運作，協助VMI觀念之釐清及推廣。模型並可協助說明並證明VMI模式實施前後供應鏈各成員之利益及風險，利於建立成員間利益共享及風險分攤之機制。並作為議定合作關係之重要參考數據。經由本模式之建立，降低了推行VMI之障礙。 本研究經由顧客需求型態的分析，選擇較精確之安全庫存量配置參數，協助供應商產能規劃，建立較為強健之VMI模式確保滿足顧客需求；經由各品項需求型態的分析，提供庫存控管及補貨作業的有效執行；最後搭配供應合約之庫存管控水準、交易條件、付款條件等狀況，較精確地規劃供應鏈整體庫存配置，降低作業成本，謀求供應鏈整體庫存配置之最佳化。製造商產能規劃、自動補貨機制與整體庫存最佳化正為VMI實務運作之困難亦為本研究之貢獻所在。