The research on micro-punching by laser-driven flyer

In the conventional mechanical punching, the size of punched holes is limited due to the difficulties of tool fabrication and punch-to-die alignment and the increasing costs of tool fabrication. In order to overcome these problems, this paper presents a novel laser-driven flyer punching technology. A flyer with a high speed punch pressure was achieved after being irradiated by a short and intense laser pulse. When the flyer loaded on the workpiece, bending and axial stretching of workpiece would take place, and the workpiece could be sheared off around the corner of die. In this paper, a single micro-hole mold was machined by the micro-milling cutter on printed circuit board and a die-opening with three holes was produced by electrical discharge machining(EDM) using the copper electrode. The micro-punching experiments were conducted on copper successfully by controlling the laser energy and good edge quality was obtained. Experimental results were observed under a XTZ-FG stereo-microscope and an AxioCSM700 scanning microscope. The novel process of punching was also numerically studied by Finite Element Mesh (FEM) and Smoothed Particle Hydrodynamics (SPH), which on the one hand, confirms this punching method could work, on the other hand, lays the foundation for optimizing the process parameters and reducing the number of experiments. With further development, the laser-driven flyer punching technology may become an important micro-punching method, which is characterized by non-contact, low cost, and high efficiency. (C) 2011 Elsevier Ltd. All rights reserved.