Abstract:
Zirconia ceramics are widely used in various industrial fields due to their excellent characteristics, such as high hardness and high melting point, however, the material is difficult to process, making it difficult to realize high-efficiency, high-quality and high-precision machining. Electro-chemical discharge machining (ECDM) of zirconia ceramics, although the energy can be increased to improve the machining efficiency, it is easy to produce a large number of micro cracks and other defects due to excessive thermal stresses within the material and other problems. Therefore, the machining of small holes in zirconia by ECDM using high-speed rotating abrasive electrodes was proposed. By comparing with traditional ECDM to analyze the machining characteristics, it is found that the abrasive electrode can enhance the stability of the gas film and reduce the thermal defects generated by the thermal shock of the discharge to improve the machining quality of small holes, and the results show that the machining accuracy has been improved by 63.9%. Furthermore, the influences of different duty cycles, electrolyte concentrations, frequencies, and rotational speeds on the machining laws of zirconia ceramics were further investigated. The suitable process parameter combination of a duty cycle of 80%, a electrolyte concentration of 15 wt%, a pulse frequency of 17.5 kHz and a rotational speed of 10 000 r/min was determined through a one-way test, and small holes up to a depth of 670.4 μm with 108.9 μm overcutting were successfully machined under this parameter combination.