Formability in Biaxial Stretch of Aluminum Sheets and Foil with Very Small Punch

采用直径分别为4.0、7.5和40mm的半球面冲床对铝箔和铜箔的成形性进行了研究。所用材料为0.2 mm和0.02mm厚度的铝板和铝箔，以及0.035mm厚度的铜箔。采用厚度为1.0mm的铝板和厚度为0.6mm的磷脱氧铜板。所有这些材料都经过了退火处理。在PTFE（聚四氟乙烯片材，公称厚度0.05mm）上滴上机械油，石墨脂和机械油作为毛坯和冲床之间的润滑剂。所得结论如下。厚度的增加提高了临界成形深度。这已经被报道过了。在这项工作中，0.2至0.02mm的厚度也得到了相同的结果。作为实现同厚效果的有效方法，提出了层压法。在这种情况下，层压片是相同的厚度或不同的或不同的材料。通过层压两层或多层，也可以提高临界成形深度。该方法能较好地提高临界成形深度。结果表明，厚度应变分布对临界成形深度有较大影响。厚度应变在坯料与凸模接触区域的均匀分布是提高临界成形深度的关键。

The formability of Aluminum foil and Copper foil was investigated using semi-spherical punch which diameter were 4.0,7.5 and 40mm.The materials used are Aluminum sheet and foil Which are 0.2 and 0.02mm in thickness, and Copper foil which is 0.035mm in thickness. Moreover, Aluminum sheet which is 1.0mm in thickness and Phosphorus deoxidized copper sheet which is 0.6mm in thickness were used. All these materials were annealed.The PTFE (Polytetrafluoroethylene sheet, nominal thickness is 0.05mm) on which machine oil was dropped, Graphite grease and Machine oil Were used as the lubricants between blank and punch. The conclusions obtained are as follows.Increasing in thickness is improved the critical forming depth. This has already been reported. In this work, same consequence for 0.2 to 0.02mm in thickness were a also obtained. As a useful method to give same thickness effect, laminating method was proposed. In this case, the sheets laminated were same thicknesses or different ones or different material ones. The critical forming depth is also improved by laminating the two or more sheets. The critical forming depth is improved fairly by this method. It is noticed that the critical forming depth is largely affected in the thickness strain distribution.It is important to improve the critical forming depth that the thickness strain is distributed uniformly over the contact region between blank and punch.