Effects of additive manufacturing processes on part defects and properties: a classification review

Additive manufacturing (AM) is an established manufacturing technology which allows for greater design freedom. Across the seven existing AM processes, we observe a variety of defects in printed parts, due to the different physical properties of each manufacturing process. This variety of defects complicates the design step without a clear overview of the deep interaction geometry-process-defect. The classification of these defects, which may be process- or machine-based, often raises methodological and terminological issues. In this paper, a review of AM general part defects using a process-based approach, is proposed. The aim of this paper is to provide the designer with a classification that would allow to make choices in the part design, by taking stock of the different defects affecting the resulting part considering the chosen process. For each process category defined in ISO/ASTM 52900, the main properties and defects of parts are reviewed and classified into four families: geometry and dimensions, surface quality, microstructure and mechanical properties. This review focuses in particular, on the process parameters which affect declined defects and properties allowing a relevant choice of the designer with respect to the process or the expected requirements of the part.