ABSTRACT As a non-traditional machining process, spark assisted chemical engraving (SACE) can machine hard, brittle, and non-conducting materials. The spark discharges on tool-electrode sidewall result in energy loss and overcut edges. A tool electrode covered with an insulating film on its sidewall is usually used to constrain the discharges to the tool-electrode end. However, not only the preparation of the insulating film is cautious and fussy, but also it is easy to split away under the high temperature and pressure action of SACE. In this research, a novel method constraining the micro-SACE discharges to the tool-electrode end was proposed by changing surface roughness of the tool electrode. The special micro-tool electrode with rough end and smooth sidewall was fabricated on-machine. The constraint effect was experimented by observing the distribution of SACE bubbles and discharges around the tool-electrode end, and the optimal parameters were obtained by evaluating the bubble aspect ratio. Furthermore, machining experiments of the micro-SACE scanning process by constraining discharges to tool-electrode end were verified on ZrO2 ceramics as a kind of difficult-to-machine material. Micro-circular grooves without micro cracks were successfully machined by the use of a Φ300 μm tool electrode.

中文翻译：

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具有不同刀具表面粗糙度的 Micro-SACE 扫描工艺

摘要 作为一种非传统加工工艺，火花辅助化学雕刻 (SACE) 可以加工硬、脆和不导电的材料。工具电极侧壁上的火花放电导致能量损失和过切边缘。通常使用在其侧壁上覆盖有绝缘膜的工具电极来限制向工具电极端的放电。但是，绝缘膜的制备不仅要谨慎、繁琐，而且在SACE的高温高压作用下容易裂开。在这项研究中，通过改变工具电极的表面粗糙度，提出了一种将微 SACE 放电限制在工具电极端的新方法。在机器上制造了具有粗糙端部和光滑侧壁的特殊微型工具电极。通过观察SACE气泡和工具电极端周围放电的分布来实验约束效果，并通过评估气泡纵横比获得最佳参数。此外，通过将放电限制在工具电极端的微 SACE 扫描工艺的加工实验在 ZrO2 陶瓷作为一种难加工材料上进行了验证。使用Φ300 μm工具电极成功加工出无微裂纹的微圆形凹槽。在作为一种难加工材料的 ZrO2 陶瓷上验证了通过将放电限制到工具电极端的 micro-SACE 扫描工艺的加工实验。使用Φ300 μm工具电极成功加工出无微裂纹的微圆形凹槽。在作为一种难加工材料的 ZrO2 陶瓷上验证了通过将放电限制到工具电极端的 micro-SACE 扫描工艺的加工实验。使用Φ300 μm工具电极成功加工出无微裂纹的微圆形凹槽。