Abstract Components with complex internal surfaces are increasingly important for gas and fluid flow applications in aerospace and automotive industries. Recently, as an emerging manufacturing technology, three-dimensional (3D) additive manufacturing (AM) technology enables one-step fabrication of these complex internal surfaces. Although 3D AM technology eliminates the need for complex assembly process, due to the poor surface and sub-surface integrity, achieving a favourable surface condition is challenging. Therefore, a post-polishing process is essential for these 3D AM complex internal surfaces. This paper presents a novel rotating-vibrating magnetic abrasive polishing method to finish a kind of complex internal surface which has a double-layered tube structure made by selective laser melting (SLM) of Inconel 718. The principle of the method was illustrated and the material removal process was modelled. The feasibility of the method was verified and the surface evolution mechanism under different motions was revealed. The effects of process parameters on material removal and surface quality were evaluated quantitatively. The results showed that material was uniformly removed from both of the external surface of inner tube and internal surface of outer tube. The uneven surface caused by partially melt powders during SLM process was smoothed and the surface roughness was reduced from about 7 μm Ra to less than 1 μm Ra. Relatively higher material removal efficiency and lower surface roughness were obtained through combining rotation and vibration motions. The surface quality was improved representing by the increase of surface nanohardness and release of residual stress after polishing. There was no subsurface deformation and damage observed so that a damage-free surface was obtained.

中文翻译：

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一种用于双层内表面精加工的新型旋振磁研磨抛光方法

摘要 具有复杂内表面的部件对于航空航天和汽车行业的气体和流体流动应用越来越重要。最近，作为一种新兴的制造技术，三维 (3D) 增材制造 (AM) 技术能够一步制造这些复杂的内表面。尽管 3D AM 技术消除了对复杂组装过程的需求，但由于表面和次表面完整性较差，实现良好的表面条件具有挑战性。因此，对于这些 3D AM 复杂的内表面，后抛光过程是必不可少的。本文提出了一种新颖的旋转振动磁研磨抛光方法，以精加工一种复杂的内表面，该内表面具有 Inconel 718 选择性激光熔化 (SLM) 制成的双层管结构。阐述了该方法的原理，并对材料去除过程进行了建模。验证了该方法的可行性，揭示了不同运动下的表面演化机制。定量评估工艺参数对材料去除和表面质量的影响。结果表明，材料从内管外表面和外管内表面均被均匀去除。SLM 过程中部分熔化粉末造成的不平整表面得到平滑，表面粗糙度从约 7 μm Ra 降低到小于 1 μm Ra。通过结合旋转和振动运动，获得了相对较高的材料去除效率和较低的表面粗糙度。抛光后表面纳米硬度的增加和残余应力的释放使表面质量得到改善。没有观察到次表面变形和损坏，从而获得无损坏的表面。