Novel 3D manufacturing method combining microelectrial discharge machining and electrochemical polishing

This paper reports on the potential of microelectrical discharge machining (μEDM) as an innovative method for the fabrication of 3D microdevices. To demonstrate the wide capabilities of μEDM two different microsystems—a microfluidic device for the dispersion of nanoparticles and a star probe for microcoordinate metrology—are presented. To gain optimized process conditions as well as a high surface quality an adequate adaption of the single erosion parameters such as energy, pulse frequency and spark gap has to be carried out and is discussed below. Thus, a surface roughness of R_a = 80 nm is achieved at the channel bottom. The fabricated stylus elements for the star probe have sphere diameters of 40–200 μm. For further surface quality enhancement a subsequent electrochemical polishing step is investigated. In case of the dispersion micromodule a combined process chain of μEDM-milling and electropolishing has reached a surface improvement above 70%.