Abstract Three-dimensional (3D) microcavities can be machined by micro-electrochemical machining (micro-ECM) using a 3D microelectrode. However, with increasing machining depths, it becomes challenging to renew electrolyte and remove the electrolytic products from the machining gap. Therefore, 3D microcavities are usually shallow and the machined surfaces are of poor quality. To address these problems, this paper proposed performing 3D microelectrode vibration-assisted micro-ECM in combination with polishing to machine 3D microcavities by using an electrolyte containing suspended B4C particles. First, a 3D microelectrode with rectangular holes on both of its undersurfaces was fabricated by means of bending-and-avoiding mode wire electrical discharge machining in combination with vacuum thermal diffusion bonding. Second, the prefabricated microelectrode was applied in vibration-assisted micro-ECM to machine deep 3D microcavities using an electrolyte containing suspended B4C particles. Thereafter, the machined surfaces of the deep 3D microcavities were polished to improve the surface quality. Furthermore, the effects of vibration amplitude and frequency, polishing time, and B4C particle concentration on the microcavity surface quality were investigated in detail. The experimental results indicate that the electrochemical reaction attachments on the microelectrode surface were removed by polishing of the particles during processing, ensuring satisfactory processability of the microelectrode, as well as a highly efficient and stable micro-ECM process. Moreover, when the vibration amplitude was set to 10 μm, vibration frequency to 30 Hz, polishing time to 30 min, and B4C particle concentration to 5 g/L for the 300 μm deep microcavity machined by the proposed method, the microcavity bottom surface roughness was minimized (Ra = 0.223 ± 0.021 μm) and the sidewall roughness was improved. Finally, based on the proposed method and optimized polishing parameters, 3D microcavities of more than 800 μm deep with rectangular and semi-cylindrical islands were obtained.

中文翻译：

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振动辅助微 ECM 与抛光相结合，使用带有悬浮 B 4 C 颗粒的电解质加工 3D 微腔

摘要 三维 (3D) 微腔可以通过使用 3D 微电极的微电化学加工 (micro-ECM) 进行加工。然而，随着加工深度的增加，更新电解液和去除加工间隙中的电解产物变得具有挑战性。因此，3D 微腔通常较浅，加工表面质量较差。为了解决这些问题，本文提出通过使用含有悬浮 B4C 颗粒的电解质，将 3D 微电极振动辅助微 ECM 结合抛光来加工 3D 微腔。首先，通过弯曲避让模式线材放电加工结合真空热扩散键合，制备了两个下表面均带有矩形孔的3D微电极。第二，将预制微电极应用于振动辅助微 ECM，以使用含有悬浮 B4C 颗粒的电解质加工深 3D 微腔。此后，对深 3D 微腔的加工表面进行抛光以提高表面质量。此外，详细研究了振动幅度和频率、抛光时间和 B4C 颗粒浓度对微腔表面质量的影响。实验结果表明，通过在加工过程中对颗粒进行抛光，去除了微电极表面的电化学反应附着物，确保了微电极的良好加工性能，以及高效稳定的微ECM工艺。此外，当振幅设置为 10 μm，振动频率设置为 30 Hz，抛光时间设置为 30 分钟时，对于通过所提出的方法加工的 300 μm 深微腔，B4C 颗粒浓度达到 5 g/L，微腔底表面粗糙度最小化（Ra = 0.223 ± 0.021 μm），侧壁粗糙度得到改善。最后，基于所提出的方法和优化的抛光参数，获得了深度超过 800 μm 的具有矩形和半圆柱形岛的 3D 微腔。