Micro-hole Manufacturing on Metal Sheet by Laser-Driven Flyer Punching

In conventional mechanical punching, the size of the punched holes is limited due to the difficulties of tool fabrication, the difficulties of punch-to-die alignment and the increasing costs of tool fabrication. In order to overcome these problems, a novel micro-hole manufacturing technique based on laser-driven flyer punching is presented. A flyer is irradiated by a short and intense laser pulse, resulting in a high speed and high punch pressure. When the flyer is loaded on the workpiece, the bending and axial stretching of workpiece would take place, and the workpiece could be sheared off around the corner of die. The single micro-hole mould with 1 mm diameter is machined by the micro-milling cutter on printed circuit board. The micro-punching experiment is conducted on copper successfully by controlling the laser energy and good edge quality is obtained. The experimental results are observed by an XTZ-FG stereo-microscope and an AxioCSM700 scanning microscope. The novel process of punching is also numerically studied, which confirms the feasibility of this method and lays the foundation for optimizing the process parameters and reducing the number of experiments.