Precision Forming of Electric and Electronic Small Parts Made of Metal Foil Using Multi-functional Forming Machine

随着坯料厚度的减小，防止起皱所需的压边压力显著增大。随着压边力的增大，拉深过程中的最大拉深应力也随着板料厚度的减小而增大。金属箔在拉深过程中容易产生断裂和起皱，使成形性能变差。为了成形超薄壳而不破坏，压边力应沿沿着最佳路径加载。除了由于坯料厚度减小而导致的失效之外，工具缺陷（诸如工具与箔坯料之间的不均匀接触、沿圆周沿着的不相等间隙以及凸模、凹模和坯料之间的不准确对准）也极大地影响起皱和断裂的发生。在成形过程中使用辅助板减少了模具缺陷的影响，并防止了毛刺和断裂。在非常薄的板上冲孔对于制造小型化部件非常重要。在爆炸冲击压力冲孔工艺中，不需要凸模，只需要一个模腔。这一工艺对于钻细孔非常有效。爆炸冲击强度对穿孔状态有很大影响。最佳强度提高了穿孔质量。箔材的种类及其机械性能也影响穿孔。

The blankholding pressure required to prevent wrinkling increased considerably with a decrease of blank thickness. The maximum deep-drawing stress also increased greatly with an increase of the blankholding pressure, according to the decrease of blank thickness. Fractures and wrinkles in deep drawing of metal foil occurred easily and the formability deteriorated. In order to form very thin shells without failure, blankholding pressure should be loaded along optimum paths. In addition to the failure due to the decrease of blank thickness, tooling imperfections such as ununiform contact between tools and the foil blank, unequal clearance along the circumference and inaccurate alignment between the punch, die and blank greatly influence the onset of wrinkling and fracturing. The use of auxiliary sheets in the formation reduced the influence of tooling imperfections and prevented wrinkling and fracturing.Piercing fine holes in very thin sheets is important in manufacturing miniaturized parts. In piercing process by means of explosive-impulsive pressure, a punch is not required but only a die cavity is required. This process will be very effective for piercing fine holes. The explosive-impulsive intensity strongly influenced the state of pierced holes. The optimum intensity improved the quality of the pierced holes. The kind of foil materials and their mechanical properties also influenced the pierced holes.