Invited review article: Metal-additive manufacturing—Modeling strategies for application-optimized designs

Abstract

Next generation, additively-manufactured metallic parts will be designed with application-optimized geometry, composition, and functionality. Manufacturers and researchers have investigated various techniques for increasing the reliability of the metal-AM process to create these components, however, understanding and manipulating the complex phenomena that occurs within the printed component during processing remains a formidable challenge—limiting the use of these unique design capabilities. Among various approaches, thermomechanical modeling has emerged as a technique for increasing the reliability of metal-AM processes, however, most literature is specialized and challenging to interpret for users unfamiliar with numerical modeling techniques. This review article highlights fundamental modeling strategies, considerations, and results, as well as validation techniques using experimental data. A discussion of emerging research areas where simulation will enhance the metal-AM optimization process is presented, as well as a potential modeling workflow for process optimization. This review is envisioned to provide an essential framework on modeling techniques to supplement the experimental optimization process.

Clinical significance of three-dimensional printed biomaterials and biomedical devices

“…In short, PBF is used to develop single-material components with fine features (such as the porous structures shown in Figure 2b-d, whereas DED is used for changing the composition of a component during printing to optimize specific sections for different operating environments, or providing a surface coating to an existing component. 7 Because the feedstock is metal powder, leaching of this powder into the body is a major concern as these structures often maintain a surface with partially melted particles. Despite this, manufacturers have used techniques such as chemical etching to remove surface particles and have eliminated the possibility of loose powder leaching from the implant surface.…”

“…Methods such as PBF and DED play a large role in this because they enable patient-specific geometry, controlled open-cell and interconnected porosity, and functional gradation from one material to another to increase implant osseointegration. 2,7,8 Investigations of porous structures produced via PBF show that their properties are largely dependent on the relative density of the final structure, the cell topology, the strut shape, and size distribution, as well as the mechanical properties of the base material (see Table II for some examples of these structures, 8,[11][12][13][14][15][16][17] as well as Figure 2b-d 6,16,18 ). The inherent challenge with creating these features is that the strut size varies along the length due to the powder-bed support during processing.…”

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

“…AM terminologies and general principles are standardized by the ISO/ASTM 52900 (2015) international standard. Dissimilar from other manufacturing technologies, AM produces parts by a layer-by-layer stacking approach [1][2][3][4][5]. The process starts from a three-dimensional (3D) computer-aided design (CAD) model of the part to be built, which is sliced in several thin layers by a appropriate software [6].…”

“…Furthermore, compressive stresses immediate to the surface were obtained in heat-treated specimens, which is not in agreement with the typical characteristics of parts fabricated by PBF-LB, i.e., tensile stresses at the surface and compressive stresses in the part's core.Diverse metals AM techniques exist, and the most adopted in the industry are Powder Bed Fusion (PBF) and Directed Energy Deposition (DED), as for the classification by the ISO/ASTM 52900 (2015) international standard. These two techniques use a laser or an electron beam as a high energy density source to selectively melt the material and build the parts [3][4][5][6][7]. Actually, different nomenclatures are used for the same process.…”

“…Its microstructure consists of a EVIEW 2 of 16 d products in the aerospace, automotive, biomedical/medical, and energy techniques exist, and the most adopted in the industry are Powder Bed ted Energy Deposition (DED), as for the classification by the ISO/ASTM 52900 ndard. These two techniques use a laser or an electron beam as a high energy ctively melt the material and build the parts [3][4][5][6][7]. Actually, different for the same process.…”