In this paper, an attempt is made to explain the surface texture of Selective Laser Melting (SLM) parts more satisfyingly than the existing methods. Investigations were carried out on the 316L stainless steel SLM samples. To account for most of the surface conditions, a truncheon artefact was employed for the analysis. A Stylus Profilometer was employed as a metrology tool for obtaining the 3D surface measurements. A methodology is proposed to extract and characterize the topographic features of Additive Manufactured (AM) surfaces. Here, the overall roughness of the surface is segregated into the roughness of the powder particles and the waviness due to thermal and the “staircase” effects. Analyzing these features individually results in an increased understanding of the AM process and an opportunity to optimize machine settings.

The increasing interest in Additive Manufacturing (AM) is due to its huge advantage in producing parts without any geometrical limitations. It is due to this reason, AM is extensively utilized in automotive, aerospace, medical and dental applications. Despite their popularity, AM is often associated with inferior surface quality which is one of the many reasons why it has failed to fully replace traditional methods. Hence, AM is always followed by a subsequent post-processing step to produce the end-product. To establish control over the surface quality it is first necessary to fully understand the surface behaviour concerning the factors affecting it. In this paper, the focus is mainly on having a better understanding of the surfaces by using scale-sensitive fractal analysis. In addition, the paper documents the influence of build inclination and post-processing in particular shot blasting on surface topography and utilizes a multi-scale approach to identify the most important scale and parameters for characterization. Results of this study reveal that shot blasting has a minimalistic effect on surface features at a large scale as it cannot remove the waviness completely. At smaller scales, blasting imparts additional features on the surface due to the impact of abrasive particles at high pressure. At the intermediate scales, the influence of shot blasting is highest as it successfully eliminates the surface features comprising of partially melted powder particles and stair-step effect. © 2020 IOP Publishing Ltd.

Additive Manufacturing (AM) is gaining prominence due to its massive advantage in fabricating components without any geometrical limitations. The most widely used AM technique is Fused Deposition Modelling (FDM). FDM is an extrusion-based AM mostly focused on producing functional prototypes and in some cases as an end-product. One of the most common challenges associated with FDM is its reduced dimensional accuracy and surface quality. A fair amount of research has been carried out to identify the factors affecting print quality and measures to reduce surface roughness. On a few occasions, it is still necessary to achieve higher precision and quality to meet the standards set by conventional manufacturing. Hence, post-processing is employed as an additional step to reach the finish required. This paper focuses on enhancing the surface quality of FDM parts by subjecting it to Acetone vapour smoothening, Shot-blasting and Laser-assisted finishing post-processing methods. A comparative study is presented in this paper, where surface produced by different post-processing methods were compared to the reference injection moulding components. The results suggest that the acetone-based process has the best surface finish compared to the other two means; however, it leaves a very glossy appearance to the part. Shot blasting is very aggressive, and blasting time has a strong influence on the part quality. Laser-assisted finishing slightly ignites the top layer during melting leading to discolouration of the part. The optimum solution was found to be combining the post-processes, which not only reduced the roughness but also enhanced the aesthetic properties of the product. © 2020 IOP Publishing Ltd.

Fused Deposition Modeling (FDM) is mostly used to develop functional prototypes and in some applications for end-use parts. It is important to study the surfaces produced by FDM to understand the certainty of process. Truncheon design test artefacts are printed at different print settings and surfaces are measured using stylus profilometer. Taguchi’s design of experiments, signal-to-noise ratio and multiple regression statistics are implemented to establish a concise study of the individual and combined effect of process variables on surface texture parameters. Further, a model is developed to predict the roughness parameters and is compared with experimental values. The results suggest significant roughness parameter values decrease with increase in build inclination and increases with increase in layer thickness except the roughness peak count. © 2018 The Authors. Published by Elsevier B.V