Micro-cutting characteristics of EDM fabricated high-precision polycrystalline diamond tools

To fabricate three-dimensional microstructures, such as micro dimples, micro grooves and micro channels, on ceramic mold materials, tool fabrication with super hard materials is an essential step. In this work, micro electro discharge machining (EDM) was used to fabricate high-precision polycrystalline diamond end mills. Form accuracy and edge sharpness in one micron level were achieved by utilizing electro discharge induced graphitization of diamond grains under extremely low discharge energy conditions. The cutting performance of the fabricated tools was examined by machining micro dimples and micro grooves on tungsten carbide mold substrates. Results showed that using the EDM-fabricated tools, ductile mode machining of tungsten carbide was realized with a surface finish of 2 nm Ra, which is comparable to that produced by polishing.

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► Diamond undergoes graphitization in EDM of PCD, enabling gradual material removal.
► Extremely low-energy electro discharge can be realized by stray capacitance.
► One micron level form accuracy and edge sharpness is producible in EDM of PCD tools.
► Smooth surface of 2 nm Ra was achieved on tungsten carbide by the EDM fabricated tools.
► Edge chippings of PCD tools were far fewer than that of single-crystal diamond end mill.