High-power millisecond laser is an efficient tool to manufacture micro holes, but the laser induced thermal defects, such as recast layer (RL), micro cracks and heat affected zone, are difficult to avoid. However, some important components, like turbine blades, are very sensitive to these defects, therefore, they must be eliminated in the manufacturing process of film cooling holes. We propose a combined processing method which includes high-power laser pre-drilling and electrochemical post-processing. One novelty of this study is that we applied a special back-bonded material (silicate mixture) under the Inconel 718 substrate, which functions as barricade to protect the opposite inner surface of the hollow blade in laser drilling, while in the electrochemical process, it functions as bottom support to form electrolyte back flow. A novel two-step inner streaming electrochemical post-processing technique was designed according to the characteristics of RL distribution in the laser pre-drilled holes. The processing strategy was optimized by a series of experiments. Finally, recast-layer free holes with clear and straight hole walls could be drilled in less than 30 s each, which is much faster than ultrafast laser drilling.

高功率毫秒激光是制造微孔的有效工具，但激光引起的热缺陷，如重铸层（RL）、微裂纹和热影响区等难以避免。然而，一些重要的部件，如涡轮叶片，对这些缺陷非常敏感，因此在薄膜冷却孔的制造过程中必须消除它们。我们提出了一种包括高功率激光预钻孔和电化学后处理的组合加工方法。这项研究的一个新颖之处在于，我们在 Inconel 718 基板下应用了一种特殊的背键材料（硅酸盐混合物），其功能是在激光钻孔中保护空心刀片的相对内表面，而在电化学过程中，它起到了路障的作用。起到底部支撑作用，形成电解液回流。根据激光预钻孔中RL分布的特点，设计了一种新型的两步内流电化学后处理技术。通过一系列实验优化处理策略。最后，可以在不到 30 秒的时间内钻出具有清晰直孔壁的无重铸层孔，这比超快激光钻孔快得多。