为了实现金属箔板大面积微弯曲成形, 本文结合激光冲击微弯曲成形技术与软模成形技术的优点, 提出了激光冲击软模大面积微弯曲成形方法。 该方法是在脉冲激光冲击波压力下, 将软模作为柔性冲头作用于金属箔板来实现工件成形的。实验中使用了Innolas Gmbit公司生产的Spitlight 2000 THG脉冲激光器, 将250 μm厚的聚氨酯橡胶薄膜作为软模, 采用德国LPKF-ProtoMat-C60型雕刻机在印刷电路板上加工出深度为120 μm的U型多槽模具, 实现了在厚度为30 μm的铜箔板上一次性对3个U型凹槽冲击成形。用KEYENCE VHX-1000C超景深三维显微系统进行工件观测, 结果显示工件上的微成形槽具有良好的轮廓质量。以ANSYS/LS-DYNA为平台, 使用有限元建模(FEM)方法对微弯曲过程进行了数值模拟。实验和模拟结果均表明, 加载软模的工件与模具的U型凹槽特征在形状上更加接近, 成形工件更加均匀, 而且具有较好的表面质量, 其最大平均成形深度可达110 μm, 大于激光直接冲击成形的最大深度(88 μm), 说明使用软模提高了充型能力。

To implement the large area micro bending forming of metal foils, this paper presents a large area micro bending method by laser shock wave based on advantages of laser shock bending forming and soft punch forming. With this method, the metal sheets would be deformed under the soft punch. In the experiments, a pulse Nd-YAG laser (Innolas Gmbit Spitlight 2000 THG) with Gaussian distribution beam was employed, and the polyurethane rubber with a thickness of 250 μm were used as the soft punch. The U-shaped grooves with a depth of 120 μm were machined on a printed circuit board with an engraving machine made in Germany(LPKF-ProtoMat-C60). After one impact, three U-shaped grooves were replicated from the mold on cooper foils with a thickness of 30 μm. Observed by the digital measurement system (KEYENCE VHX-1000C), the deformed micro grooves in the work piece own good contour shape. Besides, the numerical simulation was used to understand the micro-bending process by the ANSYS/LS-DYNA software. The experiment and simulation results show that the work pieces with soft punch have more uniform multi-groove contour shapes and good surface quality. The depth of the deformed micro grooves in the work piece reaches as deep as 110 μm, higher than that from the laser direct shock shape(88 μm). Therefore, it implies that this kind of process improves the work piece forming ability and quality.