Study on the forming of complex shaped microparts by progressive micropunching of thin copper strip

In this work, a progressive micropunching technology was proposed to form complex shaped microparts using thin copper strip with a thickness of 200 μm. The mechanical properties, microstructure and texture of the annealed thin copper strip were systematically studied, and the quality of the formed microparts through both 1-step micropunching and progressive micropunching were evaluated and discussed. The results show that annealing temperatures of 500 and 600 °C are beneficial to improve the plasticity and formability of copper strips, thereby enhancing the dimensional and shape accuracy of formed complex shaped microparts. Compared with the formed products after 1-step micropunching, the smooth zone of the microparts by progressive micropunched increases by 25%. Also, progressive micropunching significantly improves the surface finish of the cross section of formed microparts. Overall, the proposed progressive micropunching process is functional to enhance the dimensional and shape accuracy of punched parts, exhibiting superiority in comparison with 1-step micropunching process.