Micro bending method by soft punch under laser-driven flyer loading

In order to investigate the micro bending forming by soft punch under laser-driven flyer loading, this paper presents a kind of micro bending method by soft punch under laser-driven flyer loading. In the experiments, a pulse Nd-YAG laser (Innolas Gmbit Spitlight 2000 THG) with Gaussian distribution beam is employed, and the polyurethane rubbers are used as the soft punch. The U-shaped groove with 115 μm in depth is machined on the printed circuit board with the micro-milling of the circuit board engraving machine (LPKF-ProtoMat-C60). After laser impact, the 30 μm thickness cooper foils can replicate the U-shaped groove from the mold. In order to understand the micro bending deformation of metal foil sheet based on the U-shaped groove mold, the influence of various process parameters (including laser energy, the soft punch thickness) on the micro bending deformation is investigated. In addition, for comparing the micro bending experiments by soft punch under laser-driven flyer loading with the micro bending experiment based on the laser-driven flyer, the corresponding experiment is also carried out. The results show the maximum depth of the work piece can be increased by using the flyer and soft punch, the process can improve the work piece forming ability and quality.