Dynamic compression of a polymer stamper using high-impulse underwater shock waves to imprint a sub-micrometer structure on a metal plate surface

Press-forming technology is excellent for mass production. However, for micrometer-order forming, manufacturing press tools is unprofitable. Because laser-induced shock waves cannot rapidly accelerate heavier workpieces into molds, the workpieces are limited to thin metal foils. In this study, an explosion-derived high-impulse shock wave was applied to dynamically compress a polymer stamper into a metal plate. The stamper was pressed for a few microseconds, resulting in a well-imprinted submicron structure on the aluminum plate surface. Numerical simulation clarified the imprinting mechanism, which involved local compression and restoration of the stamper profile that occurred when the reflected shock wave generated at the boundary between the stamper and the workpiece reached the free surface of the stamper. It was discovered that the shock wave must continue to act for a significantly longer time than that required for the reflected shock wave to reach the free surface of the stamper. Therefore, explosion-derived shock waves with a long pressure duration are effective for imprinting. This method has the potential to be developed into a practical technique for imparting functional microsurfaces to structural components.