Abstract Laser polishing, capable of polishing selective nonplanar areas, is exploited to improve the surface roughness of additive manufactured metal components. It offers a highly repeatable, higher speed polishing process as well as low labor costs compared with traditional mechanical abrasive polishing. In spite of the fact that many studies can be found on laser polishing processes, few have reported that focus on metal components, manufactured additively by selective laser melting (SLM) technology, with geometrically different complex surfaces. This paper presents a novel method to reduce the surface roughness of Cobalt Chromium (CoCr) components with complex surface geometry by using a layered polishing method which can constantly adjust the defocusing distance of the laser along with the surface shape of the components. The optimized laser polishing parameters used were firstly obtained from the test results on planar surfaces of CoCr alloy samples and samples with complex surface geometry were then polished based on the laser parameters. Characterizations for the laser polished samples were conducted using optical profiling and scanning electron microscopy, showing that the surface roughness was reduced significantly in comparison with the as-received samples. A reduction of up to 93% in surface roughness was achieved. The mechanical hardness was also characterized by testing for Vickers hardness, which indicated the surface hardness of the laser polished samples was enhanced by 8%. Moreover, a simple and effective model was developed to illustrate the method of laser polishing on the complex surface geometry of additive manufactured CoCr alloy components. The analytical model is helpful in understanding and evaluating the underlying mechanisms of laser polishing.

中文翻译：

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具有复杂表面几何形状的增材制造 CoCr 合金部件的激光抛光

摘要 激光抛光能够抛光选择性的非平面区域，用于改善增材制造金属部件的表面粗糙度。与传统的机械研磨抛光相比，它提供了高度可重复、更高速的抛光过程以及较低的劳动力成本。尽管有许多关于激光抛光工艺的研究，但很少有报告关注金属部件，这些部件是通过选择性激光熔化 (SLM) 技术增材制造的，具有几何不同的复杂表面。本文提出了一种通过分层抛光方法来降低具有复杂表面几何形状的钴铬（CoCr）组件表面粗糙度的新方法，该方法可以随着组件的表面形状不断调整激光的散焦距离。所使用的优化激光抛光参数首先从 CoCr 合金样品平面表面的测试结果中获得，然后根据激光参数对具有复杂表面几何形状的样品进行抛光。使用光学轮廓和扫描电子显微镜对激光抛光样品进行表征，表明与接收样品相比，表面粗糙度显着降低。表面粗糙度降低了 93%。机械硬度还通过维氏硬度测试进行表征，表明激光抛光样品的表面硬度提高了 8%。此外，还开发了一个简单有效的模型来说明对增材制造的 CoCr 合金部件的复杂表面几何形状进行激光抛光的方法。