Micropunching large-area metal sheets using underwater shock wave: Experimental study and numerical simulation

Laser shock punching is a recently developed technique, which is very efficient for punching microholes in thin metal sheets. However, processing large areas with laser shock punching is difficult because the processing area is limited by the size of the laser spot. Moreover, as the duration of the laser-induced shock pressure is considerably less than that of the explosive used, the thickness of the punchable metal sheet is in the order of a few tenths of the punch diameter. In this paper, we report an efficient approach that enables micropunching over a large area of a metal sheet in a single step. This micropunching method uses an underwater shock wave generated by the explosion of a plastic explosive charge. This approach is successfully used to punch circular holes over a large area of a 0.1-mm thick A1100 sheet, forming multiple holes with a diameter of 300 μm each. The pressure profiles of the underwater shock waves measured using piezo film gauges are used to analyze the micropunching process using ANSYS Autodyn software. The punching process is numerically simulated, and it is observed that the simulation and experimental results are in good agreement. The proposed approach can be applied to high-strength materials and thick sheets that are difficult to process using laser-induced shock waves. •Micropunching method using explosives for punching a wide range of metal sheets.•The new method can be applied to high-strength materials and thick sheets.•The punching area can be increased by changing the shape of the explosive.•The shock pressure and duration can be used to control punching conditions.•The shape of the hole edge depends on the shock pressure.