原料採購模式之研究-以銅金屬為例

Abstract

近年來，中國、印度等新興國家的經濟建設呈現高度成長，促使能源與原物料的需求持續上揚；另外，全球金融受到美國次級房貸問題的衝擊，美元持續疲軟，大量的資金湧入商品市場進行避險、套利或投機，使得原物料價格的漲勢不斷地被哄抬；然而，原物料的商品供給量卻並未明顯增加，致使國內廠商面臨材料供貨吃緊與原料價格上漲的雙重壓力。 本研究以銅金屬為對象，應用時間序列方法，預測銅金屬在倫敦金屬交易所（LME）的庫存量，並利用銅庫存量與銅價為反向關係來探究未來一個月銅價走勢。研究期間以2006年1月1日到2008年6月30日銅金屬在倫敦金屬交易所（LME）的庫存量及現貨價之日資料作為實證研究資料。本研究分析移動平均法、指數平滑法與線性迴歸法的預測結果顯示，LME銅庫存量最佳預測模式為三個月加權移動平均法，每期權重（80%，10%，10%）。利用三個月加權移動平均法預測LME銅庫存量與銅價變化趨勢，推導出最適採購決策模式，並使其採購成本約可降低2.3%。 本研究結果顯示預測方法的使用，有助於IC封裝產業降低材料上漲所造成的資金壓力與購料風險，並將獲得最佳的經營效益。

Due to the fact that the infrastructure of the emerging countries such as China and India increase greatly recently years, the demand of energy and raw material continues to rise. Moreover, the American subprime mortgage has been affecting the global finance, causing the depreciation of US dollars and the massive funds to invest on the commodity market for hedge, arbitrage or gamble. In addition to those circumstances driving up the price of raw material, the supply of raw materials does not increase obviously. These bring a tremendous pressure on the raw materials shortage and the price increasing. This research on the subject of the copper metal applies the time series model to forecast the storage in London Metal Exchange (LME), and adopts the negative correlation between the stock quantity and the copper price to explore next month trend of the copper price. The statistics quote the daily transactions of both the storage and the spot price in LME from January 1, 2006 to June 30, 2008. Comparing among the moving average method, the exponential smoothing method and the linear Regression, this study shows that the optimum prediction pattern for the LME copper storage is the latter method with the three-month weighted moving average method weights applied(80%,10%,10). Using this method to forecast the variation of the storage and price, it can be inferred that the most suitable purchase decision-making pattern can reduce the procurement costs approximately 2.3%. This demonstration with the prediction pattern is helpful to IC packaging company to reduce the capital pressure and the risk for procuring materials, and to obtain the best business benefit.