A review of metal additive manufacturing technologies: Mechanism of defects formation and simulation of melting and solidification phenomena in laser powder bed fusion process

Kyogoku, Hideki; Ikeshoji, Toshi-Taka

doi:10.1299/mer.19-00182

Cited by 67 publications

(28 citation statements)

References 31 publications

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“…This section mainly reports the latest research status of the modelling and simulation of the molten pool behaviour of multi-material L-PBF. The simulations of L-PBF processes can be categorised into three: macroscopic, mesoscopic, and microscopic (Kyogoku and Ikeshoji 2020;Tan, Sing, and Yeong 2020). A limited number of studies are based on the macroscopic (Bandyopadhyay and Heer 2018) and microscopic methods (Mohanty and Hattel 2017) for multi-material L-PBF modelling.…”

Section: Understanding Molten Pool Behaviour In Multi-materials L-pbf By Modelling and Simulationmentioning

confidence: 99%

Recent progress and scientific challenges in multi-material additive manufacturing via laser-based powder bed fusion

Wei¹,

Li²

2021

Virtual and Physical Prototyping

120

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Multi-material additive manufacturing provides a new route for fabricating components with tailored physical properties. Laser-based powder bed fusion (L-PBF), also known as selective laser melting, is a powder bed-based additive manufacturing technology. This technology affords the advantage of manufacturing metallic and non-metallic materials with high geometrical resolution. An emerging field relevant to the foregoing is multi-material L-PBF. This paper reviews the latest progress in this field including multiple material powder deposition mechanisms, molten pool behaviour, process characteristics of printing metal-metal, metal-ceramic, and metal-polymer multiple material components, and potential applications. Finally, scientific and technological challenges are presented.

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Section: Understanding Molten Pool Behaviour In Multi-materials L-pbf By Modelling and Simulationmentioning

confidence: 99%

Recent progress and scientific challenges in multi-material additive manufacturing via laser-based powder bed fusion

Wei¹,

Li²

2021

Virtual and Physical Prototyping

120

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“…Generally, there are two types of pores in parts manufactured by PBF-LB, irregular shaped LOF defects and spherical pores attributed to gas entrapment [38][39]. LOF defects are of elongated, irregular shape and of strongly varying size.…”

Section: = (2)mentioning

confidence: 99%

Development of an Empirical Process Model for Adjusted Porosity in Laser-Based Powder Bed Fusion of Ti-6Al-4V

Emminghaus

Paul

Hoff

et al. 2021

Preprint

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A promising approach to address the mismatch of bone and implant stiffness, leading to the stress-shielding phenomenon, is the application of functionally graded materials with adjusted porosity. Although defect formation and porosity in laser-based powder bed fusion of metals (PBF-LB/M) are already widely investigated, so far there is little research on the influences and parameter interactions regarding the pore characteristics. This work therefore aims to provide an empirical process model for the generation of gas porosity in the PBF-LB process of Ti-6Al-4V. For the first time, parts with closed locally adjusted porosity of ~ 6 % achieved through gaseous pores instead of lack-of-fusion defects or lattice structures were built by PBF-LB. Parameter variation and evaluation of relative density, pore size and sphericity was done in accordance with the design of experiments approach. A parameter set for maximum gas porosity (laser power of 189 W, scanning speed of 375 mm/s, hatch spacing of 150 µm) was determined for a constant layer thickness of 30 µm and a spot diameter of 35 µm. Tensile tests were conducted with specimens consisting of a core with maximum gas porosity or lack-of-fusion porosity, respectively, and a dense skin as well as fully dense specimens. Whereas lack of fusion defects can lead to significant reduction of stiffness, the elastic modulus remained unchanged when implementing spherical pores. Nevertheless, the found superior strength and ductility of specimens with gas porous core underline the advantages of adjusted porosity for the application in functionally graded materials and lightweight applications.

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“…The correlation between the shape and size of the melt pool/single tracks and porosity in 3D parts has been proven in many investigations (Yadroitsev, 2009;Tran and Lo, 2019;Kuo et al, 2020). The occurrence of defects during the L-PBF process was also described in detail in Kyogoku and Ikeshoji (2020) and Oliveira et al (2020).…”

Section: Introductionmentioning

confidence: 99%

Monitoring of Laser Powder Bed Fusion by Acoustic Emission: Investigation of Single Tracks and Layers

et al. 2021

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Quality concerns in laser powder bed fusion (L-PBF) include porosity, residual stresses and deformations during processing. Single tracks are the fundamental building blocks in L-PBF and their shape and geometry influence subsequent porosity in 3D L-PBF parts. The morphology of single tracks depends primarily on process parameters. The purpose of this paper is to demonstrate an approach to acoustic emission (AE) online monitoring of the L-PBF process for indirect defect analysis. This is demonstrated through the monitoring of single tracks without powder, with powder and in layers. Gas-borne AE signals in the frequency range of 2–20 kHz were sampled using a microphone placed inside the build chamber of a L-PBF machine. The single track geometry and shape at different powder thickness values and laser powers were studied together with the corresponding acoustic signals. Analysis of the acoustic signals allowed for the identification of characteristic amplitudes and frequencies, with promising results that support its use as a complementary method for in-situ monitoring and real-time defect detection in L-PBF. This work proves the capability to directly detect the balling effect that strongly affects the formation of porosity in L-PBF parts by AE monitoring.

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A review of metal additive manufacturing technologies: Mechanism of defects formation and simulation of melting and solidification phenomena in laser powder bed fusion process

Cited by 67 publications

References 31 publications

Recent progress and scientific challenges in multi-material additive manufacturing via laser-based powder bed fusion

Recent progress and scientific challenges in multi-material additive manufacturing via laser-based powder bed fusion

Development of an Empirical Process Model for Adjusted Porosity in Laser-Based Powder Bed Fusion of Ti-6Al-4V

Monitoring of Laser Powder Bed Fusion by Acoustic Emission: Investigation of Single Tracks and Layers

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