An overview of surface roughness enhancement of additively manufactured metal parts: a path towards removing the post-print bottleneck for complex geometries

Abstract

Since the advent of additive manufacturing (AM) (also called 3D-printing), substantial progress has been achieved in technological advances in the processes and micro/macro characteristics of the components. However, this rapidly evolving field is faced with some barriers to industrial adoption, especially in the case of metals processing. Poor surface quality and surface topography imperfections, which are inherent in metal AM, are among the main drawbacks hindering AM broad industrial adoption. This issue cannot be addressed only by AM process optimization due to the intrinsic complexity of the process. Therefore, effective surface post-treatment methods are required to enhance the surface quality of the final parts for both external and hard-to-reach internal surfaces. Considering the importance and urgent need for surface modification of AM metals, this review aims to provide a broad overview of the existing research endeavors as well as gaps and opportunities in the surface enhancement of AM metals, with a focus on solution-based approaches to improve surface roughness of complex metal 3D-printed parts with intricate surfaces and evaluate the effect of these approaches on the functional properties for end-use applications. Assessing the effectiveness of the surface modification techniques, the present paper further provides the research needs to fulfill the performance-impacting knowledge gap for AM industrial adoption and further expansion of surface treatment methodologies for improved surface finish of complex metal printed parts.