Fabrication of TiN-Cu Electrical Discharge Machining Electrode by Vacuum Freeze Drying and Microwave Sintering

The TiN-Cu electrical discharge machining (EDM) electrode was fabricated by vacuum freeze drying and high-vacuum microwave sintering, instead of conventional vacuum drying and sintering via resistive heating.The influence of the fabrication conditions, including the pressure, freezing, microwave power, sintering temperature/time and heating rate, on the quality of TiN-Cu EDM electrode was investigated through orthogonal experiment and with scanning electron microscopy to optimize the fabrication conditions.The results show that the freeze-drying combined with microwave sintering in vacuum significantly improved the quality of TiN-Cu EDM electrode.For instance, under the optimized conditions, the new TiN-Cu EDM had a relative loss-rate of 3.55%, much lower than that of commercially Cu-EDM electrode.The possible mechanisms, explaining the lower blank shrinkage rate and smaller relative loss-rate of TiN-Cu EDM electrode, were also tentatively discussed.