Micro Stretch Forming of Foil using Lithography Process

即使在像铝这样具有良好成形性的材料中，当板材厚度像铝箔那样急剧减小时，冲压件的拉伸性也会降低。本研究针对这种厚度较小的材料，给出了一种形成圆顶形状的方法。成形过程的原理不是平面拉伸，而是厚度方向的压缩。流程如下：首先，纸是皱巴巴的，其次，波纹纸像灯笼一样伸展。本研究从机械生产瓦楞纸板入手。齿形刀具采用直径为0.5 mm的圆柱销，将厚度为20 μm的铝箔压在平模上。结果，平箔起皱而成为瓦楞片。该波纹板进行了拉伸试验，获得了较大的伸长率。其次，研究了用光刻工艺生产波纹片材的方法。抗蚀剂是用纺纱机涂上的，然后用烘箱烘干。然后用Hg-Xe灯照射，进行显影和蚀刻处理。条纹图案的面具是为自己制作的。对光刻后的铝箔表面进行了检查，发现其刻槽形成规律。该工艺适用于铝箔的两面。测量了加工后板材的极限拉伸应变。结果发现，与我们的预期相反，只获得了很小的应变。因此，必须首先分析破裂的机制。

The punch stretchability lowers even in the material which has good formability like aluminum, when the sheet thickness extremely decreases like the foil. This study aims for such material with small thickness to give a method for forming dome shape. The principle of the forming process is not tension in plane but compression for the thickness direction. The process is as follows ; first, the sheet is wrinkled, and the second the corrugated sheet is extended like a lantern. This study started from to produce the corrugated sheet by mechanical means. The tooth-profile tool was made by cylinder pin of 0.5 mm diameter, and the tool compressed the aluminum foil of 20 μm thickness against a flat die. As a result, the flat foil wrinkled and became the corrugated sheet. This corrugated sheet received tensile test, and large elongation was obtained. Next, the method for producing the corrugated sheet by the lithography processing was examined. The resist was applied by the spinner, and dried by the oven. Then, it was exposed by the Hg-Xe lamp, and the treatment of the development and the etching were carried out. The mask of the stripe pattern was made for oneself. The surface of the aluminum foil after the lithography processing was examined and it was found that the grooves were made regularly. This processing was applied for the both sides of aluminum foil. The limit tensile strain of the processed sheet was measured. As the result, it was found that only small strain was obtained against our expectation. So, it was clarified that the mechanism of the rupture had to be analyzed first of all.