Fabrication of micro punching mold for micro complex shape part by micro EDM

Micro punching process is suitable for mass production of micro parts. It is a challenge to fabricate micro punching mold with complex cross-sectional shape on-machine. The micro punching system’s structure design has to meet the requirement of large punching force. In this study, a micro punching system has been developed with a micro electrical discharge machining (EDM) module. A series of machining operations, from the fabrication of micro molds to punching, have been completed with no secondary clamping error. The micro die and reversed electrode are prepared using micro EDM milling. The micro punch is fabricated using reversed electrode. The punching clearance is around 11 μm. Complex shape punched holes and blanked parts have been successfully fabricated on copper, brass, 304 stainless steel, and 3J21 alloy. After punching, there was no damage on the edges of micro die and micro punch. The key dimensional error of blanked part varies by different materials, which is less than 2.5 μm.