Abstract In order to reduce the thickness of recast layer and improve the surface quality of film cooling holes, a novel high speed self-adjusting electrical discharge machining (EDM)/ electrochemical machining (ECM) approach was developed by applying two independent flushing systems that were able to switch automatically in the machining process. The new flushing systems used different work-liquids and online dynamically changing discharge parameters. With the change in gap distance and the depth of the hole drilled, the dominant machining mechanism is graduated changed from EDM to electrochemical discharge machining (ECDM) and ECM. The formation mechanism of the recast layer on nickel alloy was investigated by comparing the surface characters of the bulk material and those of the recast layer using transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). The results from comparison experiments, in which different discharge parameters and sustaining time were applied, show that this new flushing systems would ensure much better flushing continuity of the working fluid and improve the discharge gap status. In addition, low voltage and current would benefit the ECM process and the removal of recast layer.

中文翻译：

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自调式 EDM/ECM 高速钻孔薄膜冷却孔

摘要 为了减少重铸层厚度，提高薄膜冷却孔的表面质量，采用两个独立的冲洗系统开发了一种新型的高速自调放电加工（EDM）/电化学加工（ECM）方法。可在加工过程中自动切换。新的冲洗系统使用不同的工作液体和在线动态改变排放参数。随着间隙距离和钻孔深度的变化，主导加工机制逐渐从电火花加工到电化学放电加工（ECDM）和ECM。使用透射电子显微镜（TEM）和能量色散X射线光谱（EDS）比较块体材料和重铸层的表面特征，研究镍合金上重铸层的形成机制。应用不同放电参数和持续时间的对比实验结果表明，这种新的冲洗系统将确保工作流体更好的冲洗连续性并改善放电间隙状态。此外，低电压和电流将有利于 ECM 工艺和重铸层的去除。表明这种新的冲洗系统将确保工作流体更好的冲洗连续性并改善放电间隙状态。此外，低电压和电流将有利于 ECM 工艺和重铸层的去除。表明这种新的冲洗系统将确保工作流体更好的冲洗连续性并改善放电间隙状态。此外，低电压和电流将有利于 ECM 工艺和重铸层的去除。