本論文係在液壓成形（Hydroforming）的方式下進行最佳化下料加工之研究，同時探討下料斷面光亮度（clean-cut surface）和成品精度之問題。本論文研究的方式係採用田口式品質工程法，配合有限元素模擬分析軟體DEFORM-2D進行模擬分析，來選擇下料加工影響之相關可控參數，並預測最佳製程參數。因此，本法在開模前就能瞭解變形趨勢之所在，並以自行建構之液壓成形模具，進行實驗並將所得結果加以分析。經本論文研究後發現：本法經田口式最佳化後之製程參數(模具間隙、上模圓角半徑、下模圓角半徑)，在液背壓力為一定值範圍內，其理論之最佳預測值和實驗值相吻合。除此之外，在不同液壓背壓下，下料斷面光亮度之高度，將隨液壓背壓之增高而變高；相對之下，下料後所產生的毛邊高度，也會隨液壓背壓之增高而減小。 Hydro-blanking processes were studied on the optimization considerations of Taguchi’s Method. In this research, the problems of cross section of shining clean-cut surface and the finished product accuracy were discussions. To make an optimal choices of blank parameters, the finite element method with the package DEFORM-2D were used. Consequently, an optimization die obtained from the Taguchi’s Method were designed and manufactured. It was shown that the results obtained by this method were good coincidence with the experiments. In addition, It was worthy to note that the height of clean-cut surface were directly proportional to the increase of the hydraulic pressure on back of specimen and contrary to the height of blanked burr.