Mechanical punching of 15 μm size hole

This study investigates the size limit of a hole produced by the conventional punching process. In the micron size hole punching, there are two main technical obstacles that complicate the miniaturization steps. One is the fabrication of the micro punch tools with high dimensional accuracy and the other is the accurate alignment of the tools within the die clearance of 1∼2 μm. In this study, we tried to mechanically punch a 15 μm size hole. For this, we fabricated and aligned the punch tools. Micro punch tools made of tungsten carbide were fabricated by micro-electrical discharge machining (micro-EDM). The diameter of punch tip was 15 μm, and that of the die hole, 17 μm. With the developed micro punching system, tools were aligned, and then, 15 μm size holes were made on 13-μm-thick brass and stainless steel foil, respectively.