ABSTRACT

The current state-of-the-art metal additive manufacturing (AM) process still cannot meet the high industry requirements in terms of surface roughness. In addition, there are limited ISO/ASTM standards on the post-processing of metal AM components. Considerable efforts have been made to close these current gaps and challenges for standardization. In this review, First, all the existing ISO/ASTM standards under the jurisdiction of ASTM Committee F42 on additive manufacturing technologies are briefly discussed. Second, two of the most promising additive manufacturing processes: powder bed fusion (PBF) and directed energy deposition (DED), as well as their common defects of AM components, are thoroughly reviewed. The build quality, surface finish characteristics, and dimensional integrity of the as-built AM components are still not satisfactory (i.e., Ra > 5 µm and Rz > 100 µm). Third, the review is focused on identifying potential solutions to surface-finish complex additive manufactured geometries and reduce the surface roughness to meet the industry requirements (i.e., Ra < 1 µm and Rz < 20 µm). Current state-of-the-art surface finishing techniques, their material removal mechanisms, process parameters, advantages, and limitations to post-process PBF components are discussed. The technical gaps and future perspectives in enhancing the surface quality of AM components are outlined.

摘要

就表面粗糙度而言，当前最先进的金属增材制造（AM）工艺仍不能满足较高的行业要求。此外，在金属AM组件的后处理方面，存在有限的ISO / ASTM标准。为了弥补这些当前的差距和标准化挑战，已经做出了巨大的努力。在这篇评论中，首先，简要讨论了ASTM F42委员会关于增材制造技术的所有现有ISO / ASTM标准。其次，对最有前途的两种增材制造工艺：粉末床熔合（PBF）和定向能量沉积（DED）以及AM组件的常见缺陷进行了全面回顾。制成的AM组件的制造质量，表面光洁度特性和尺寸完整性仍然不令人满意（即，Ra > 5 µm，Rz > 100 µm）。第三，审查的重点是确定表面处理复杂添加剂制造的几何形状并降低表面粗糙度以满足行业要求（即Ra <1 µm和Rz <20 µm）的潜在解决方案。讨论了当前最先进的表面精加工技术，其材料去除机理，工艺参数，优点以及对后处理PBF组件的限制。概述了增强AM组件表面质量的技术差距和未来前景。