Working end wear of 3D-laminated microelectrode in reverse-polarity PMEDM with Gr and Cu powders

For the preparation of complex three-dimensional (3D) microstructures with large depth, the 3D-laminated microelectrode reverse-polarity multi-material powder-mixed electrical discharge machining (PMEDM) technology can avoid problems encountered in thermal diffusion bonding 3D-laminated microelectrode conventional micro-EDM such as large electrode wear and obvious seam discharge ridges on the machined surface. However, there is no relevant report on the wear law and mechanism of the triple junction intersection where the electrode is prone to concentrated discharge in reverse-polarity PMEDM with graphite (Gr) and Cu powders of 3D-laminated microelectrode. Based on this technology, the paper systematically analyzed the main elements' composition both its formation mechanism of the deposition layer for the interlayers self-welding regions of the 3D-laminated microelectrode and the end-faces of the two-dimensional (2D) foils. The impact of Gr and Cu powder concentrations, voltage pulse width Ton and voltage pulse interval Toff, and processing voltage on the wear of the triple junction intersection at the end of the 3D-laminated microelectrode were focused studied. Results suggested that the appropriate processing efficiency formed by the matching parameters and the multi-quality protective film deposited on the 3D-laminated electrode working surface could effectively reduce the wear curvature at the electrode triple junction intersection to R42 mu m, indicating the potential of this approach in precision manufacturing of 3D microstructures.