Large-scale metal additive manufacturing: a holistic review of the state of the art and challenges

Lehmann, Thomas; Rose, Dylan; Ranjbar, Ehsan; Ghasri-Khouzani, Morteza; Tavakoli, Mahdi; Henein, H.; Wolfe, Tonya; Qureshi, Ahmed Jawad

doi:10.1080/09506608.2021.1971427

Cited by 41 publications

(10 citation statements)

References 409 publications

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“…Traditionally, casting and forging produce near−equilibrium microstructures, but excessive cooling rates during solidification in additive manufacturing produce non−equilibrium microstructures. Thermal cycling induced by the duplicate deposition of new molten layers on the solidified layer also leads to iterative microstructural evolution [ 39 ]. Some key parameters affect specimen quality, including building layer thickness, laser power, hatch spacing, scanning speed, etc.…”

Section: Advanced Additive Manufacturing Techniquesmentioning

confidence: 99%

The Characteristic Microstructures and Properties of Steel-Based Alloy via Additive Manufacturing

Shang

Pan

et al. 2023

Materials

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Differing from metal alloys produced by conventional techniques, metallic products prepared by additive manufacturing experience distinct solidification thermal histories and solid−state phase transformation processes, resulting in unique microstructures and superior performance. This review starts with commonly used additive manufacturing techniques in steel−based alloy and then some typical microstructures produced by metal additive manufacturing technologies with different components and processes are summarized, including porosity, dislocation cells, dendrite structures, residual stress, element segregation, etc. The characteristic microstructures may exert a significant influence on the properties of additively manufactured products, and thus it is important to tune the components and additive manufacturing process parameters to achieve the desired microstructures. Finally, the future development and prospects of additive manufacturing technology in steel are discussed.

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Section: Advanced Additive Manufacturing Techniquesmentioning

confidence: 99%

The Characteristic Microstructures and Properties of Steel-Based Alloy via Additive Manufacturing

Shang

Pan

et al. 2023

Materials

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“…This increased heat can cause the evaporation of some alloying metals, such as zinc and magnesium, resulting in porosity. 5 Porosity is a concern in the application of ground-based astronomical equipment where instruments are housed within vacuum chambers operating at cryogenic temperatures. Porous materials can contain trapped gas and contaminants, which can lead to increased outgassing which can adversely affect neighbouring components.…”

Section: Wire Arc Additive Manufacturingmentioning

confidence: 99%

“…Large-scale parts are being made using DED at Relativity Space, MX3D, MER corporation, AML3D and AMFG. 5 Although DED has its disadvantages, namely that parts often contain material defects such as porosity, it can manufacture large freeform components on the metre and multi-meter scale.…”

Section: Introductionmentioning

confidence: 99%

Lightweighting large optomechanical structures in astronomy instrumentation utilising generative design and additive manufacturing

Wells,

Westsik,

Chahid

et al. 2023

Optomechanical Engineering 2023

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Ground-based astronomical instruments have mass limits to ensure they can operate safely and accurately. Reducing the mass of optomechanical structures relieves mass budget for other components, improving the instrument's performance. Many industries have adopted generative design (GD) and additive manufacturing (AM; 3D printing) to produce lightweight components. This is yet to be implemented in ground-based astronomical instrumentation; this paper aims to provide insight into the advantages and limitations of this approach. The project studied the Extremely Large Telescope (ELT) Mid-infrared Imager and Spectrograph (METIS) threemirror anastigmat (TMA); comparing the conventional, subtractive machined design with GD-AM designs. The TMA was selected due to its bespoke geometry constrained by an optical path, a conventional design which did not consider mass reduction, the size of the part (615 mm × 530 mm × 525 mm) that necessitated a study of different AM methods, and the operational environment (70 K & 10 −6 Pa).The study created mass-optimised designs of the TMA using topology optimisation and field-driven design. The performance of these designs was analysed using finite element analysis and optical ray tracing. It was found that GD-AM designs pass the required optical, structural and modal requirements, with a greater than 30% weight reduction when compared to the conventional design. The study investigated wire arc additive manufacturing (WAAM), a viable method of manufacturing components of the TMA's size. To commence the validation of WAAM for cryogenic environments, samples of WAAM aluminium 5356 were created and studied. The internal and external dimensions of two samples were investigated using X-ray computed tomography and the outgassing rate of two sets of three samples were evaluated to quantify the difference between machined and as-built samples.

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“…A large variety of processes is available for AM of metals [6]. The process chain for these methods is basically identical.…”

Section: Am Of Metallic Componentsmentioning

confidence: 99%

The effects of building position on surface and fatigue of DED-arc steel components

et al. 2022

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Recently, additive manufacturing (AM) of structural metallic components is analyzed regarding its potential use by industry and research. Next to the development of manufacturing processes, the mechanical properties are under investigation today. One of the quality measures of metallic components is the surface topography. DED-arc processes (direct energy deposition) result in relatively coarse surfaces, characterized by a distinct waviness with wave amplitudes in the mm-range. This is enhanced when applying horizontal building position in comparison to vertical position. Next to increased waviness, the load-bearing net cross sections are reduced as well. The surface topography determines the fatigue life properties of metallic components. While stress raising surface effects are generally well understood and fatigue (Structures 31: 576–589, 2021) of welded metals is established well, the fatigue behaviour of additively manufactured components is less investigated yet. In order to define surface quality levels for DED-arc components, the effects of surface topography on mechanical performance need to be understood. This article presents the manufacturing of high strength steel test coupons by the DED-arc process. The process parameters were varied with regard to the building position and different levels of surface quality were generated. The surfaces of different specimens were characterized and fatigue tests were conducted. The results were used to derive the surface influence on both, the effective load-bearing wall thickness and notch effects induced by the layer-by-layer building approach. A correlation between building position, surface waviness and fatigue strength was proven. In general, higher waviness resulted in reduced effective wall thickness and lowered fatigue strength. A difference in fatigue strength at 2 million load cycles of 20 to 30% was proven when printing in different building positions. The surface effect can be captured in the design concept when applying the effective notch stress approach with an averaging length of of ρ* = 0.4 mm. The fatigue strength is describable by a design S–N curve FAT160 and a k-value of 4.

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Large-scale metal additive manufacturing: a holistic review of the state of the art and challenges

Cited by 41 publications

References 409 publications

The Characteristic Microstructures and Properties of Steel-Based Alloy via Additive Manufacturing

The Characteristic Microstructures and Properties of Steel-Based Alloy via Additive Manufacturing

Lightweighting large optomechanical structures in astronomy instrumentation utilising generative design and additive manufacturing

The effects of building position on surface and fatigue of DED-arc steel components

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