【正文】 the deep drawing process: excessive speeds can cause wrinkling or fracture in the formed part and damage of the tooling: while insufficient speeds reduce the rate of production. In this investigation a drawing speed of 4 mm/sec is found to be the most suitable speed. The blank holder force is chosen to be the minimum force required to prevent wrinkling of the largest blank and is found to be 350kgf. An operation sequence is arranged for the tests and the punch forces are measured simultaneously as function of test variables. The airpressure is applied until the load 7 reaches the maximum load because the airpressing after reaching the maximum load no longer affect better deep drawability. Each test is repeated two or three times, average values being obtained. All experiments were carried out by the cupdrawing operation shown in Fig. 3 and experimental variables applied in this study are described in Table 2. Press oil, mercial grade high pressure hydraulic oil, is brushed on to the blank before forming to diminish the friction at the contact interface. The effectiveness of the airpressing was judged by LOR that is determined by the maximum size of blank that could be formed into a cup, since the blank size determines the maximum cup depth, and can be measured more accurately. 3. Results and Discussion To investigate the effect of air pressing on the deep drawability, the LOR is obtained at each process condition. For the calculation of LOR, the maximum blank diameter, this diameter being that below which the blanks will be drawn successfully and above which tearing will occur in the cup wall is determined. 8 Figure 4 shows the variation of LOR with increasing air pressure for AI1050 and Fig. 5 shows photograph of deep drawn cups at given process conditions. Above figures show that higher LOR is obtained at higher internal airpressure. The reason for the increased LOR at higher air pressure can be explained by thickness profile of cross sectioned cup shown in Fig. 6. Figure 6 shows that the overall thickness of deep drawn cup and the degree of thickness 9 variation at rounding part are decreased at the air pressure of 70 kg/mm39。 大多數(shù)合金鋁有一個 R 值（塑性各向異性值 ） 在 ~ 之間 。 Date and Padmanabhan, 1992。 在這項工作中，研究內(nèi)部壓力對鋁板成形性能的影響，以提高鋁合金的的拉深極限比。 3 一種可能的方式，這是空氣 壓利用專門設(shè)計的沖床 通氣在板料 內(nèi)部表面的。 5 圖 3 示意本研究中使用的凸、凹模。 6 在拉深前，板料涂上高潤滑油，以降低板料成形時的接觸摩擦。 圖 7 顯示了空氣壓對拉深的影響載荷位移曲線，在一般情況下，板料的直徑大拉深力也增大，而這個數(shù)據(jù)表明了，在高空氣壓下，板料的直徑增大，拉深最大載荷并沒有一直增大，這就是說，內(nèi)部空氣壓有助于降低拉深力和板料摩擦力。 10 參考資料 Chen X. and Sowerby R., 1996, Blank Development and the Prediction of Earing in Cup Drawing, International Journal of Mechanical Science, Vol. 8, , pp. 509516. Date . and Padmanabhan ., 1992, On the Prediction of the Forming Limit Diagram of Sheet Metals, International Journal of Mechanical Science, Vol. 34, , pp. 363374. Hrivnak A. and Sobotova L.,1992, The Influence of the Deformation Aging and the Conditions of Stress on the Properties of the Deep Drawing Steel Sheet, Journal of Materials Processing Technology, Vol. 34, pp. 425430. Johnson W. and Mellor .,1983 Engineering Plasticity, 2nd Ed., Ellis Horwood, Camelot Press, UK. Kawai N. et al., 1992,Friction Behavior in the Cup Ironing Process of Aluminum Sheets., Journal of Engineering for Industry, Vol. 114, ., 1997, Prediction of the Limiting Drawing Ratio and the Maximum Drawing Load in CupDrawing, International Journal of Machine Tools and Manufacture, Vol. 37, , pp. 201213. Lange K., 1985, Handbook of Metal Forming, McGrawHill, New York, pp. 2022. Roger P., 1991, Sheet Metal Forming, Adam Hilger, New York, pp. 181242. Thiruvarudehelvan S. and Loh ., 1993, Drawing of Cylindrical and Hemispherical Cups using an Imp