Process defects and<i>in situ</i>monitoring methods in metal powder bed fusion: a review

Grasso, Mario; Colosimo, Bianca Maria

doi:10.1088/1361-6501/aa5c4f

Cited by 617 publications

(274 citation statements)

References 115 publications

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“…The emergence of various defects during AM of metals has been studied by many researchers and has recently been reviewed by Grasso and Colosimo [23]. The formation of spherical pores is a commonly occurring defect, which, as indicated by Vilaro et al [20], is caused by the presence of gas among the powder particles dissolved in the melt pool, which remains in the material due to rapid solidification.…”

Section: Build Defects and The Influence Of Gas Flowmentioning

confidence: 99%

A Review of the As-Built SLM Ti-6Al-4V Mechanical Properties towards Achieving Fatigue Resistant Designs

Agius

Kourousis

Wallbrink

2018

Metals

171

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Ti-6Al-4V has been widely used in both the biomedical and aerospace industry, due to its high strength, corrosion resistance, high fracture toughness and light weight. Additive manufacturing (AM) is an attractive method of Ti-6Al-4V parts' fabrication, as it provides a low waste alternative for complex geometries. With continued progress being made in SLM technology, the influence of build layers, grain boundaries and defects can be combined to improve further the design process and allow the fabrication of components with improved static and fatigue strength in critical loading directions. To initiate this possibility, the mechanical properties, including monotonic, low and high cycle fatigue and fracture mechanical behaviour, of machined as-built SLM Ti-6Al-4V, have been critically reviewed in order to inform the research community. The corresponding crystallographic phases, defects and layer orientations have been analysed to determine the influence of these features on the mechanical behaviour. This review paper intends to enhance our understanding of how these features can be manipulated and utilised to improve the fatigue resistance of components fabricated from Ti-6Al-4V using the SLM technology.

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Section: Build Defects and The Influence Of Gas Flowmentioning

confidence: 99%

A Review of the As-Built SLM Ti-6Al-4V Mechanical Properties towards Achieving Fatigue Resistant Designs

Agius

Kourousis

Wallbrink

2018

Metals

171

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“…The main limitation of this technology is the limited range of filaments commercially available. Moreover, the quality of printing can be disturbed by issues such as filament break, filament thickness, and length . However, novel technologies, capable of printing raw materials from pellets and also of heating the receiving support or substrate, are now on the market.…”

Section: Introductionmentioning

confidence: 99%

“…3D printing or polymer additive manufacturing (PAM) could be a solution to overcome this limitation. 1 Several 3D techniques have emerged these last years, such as (a) fused deposition modeling (FDM) ( Figure 1A) [1][2][3][4] ; selective laser sintering ( Figure 1B), which uses a laser as the power source to sinter and bind powdered material to create a solid structure, [5][6][7] and (b) stereolitography apparatus (SLA; with liquid or powder), 8 which is based on photopolymerization and therefore using light to link chains of molecules, forming polymers and thus making up a three dimensional solid ( Figure 1C). Among these technologies, FDM presents the best quality to cost ratio.…”

mentioning

confidence: 99%

“…Moreover, the quality of printing can be disturbed by issues such as filament break, filament thickness, and length. 2,4 However, novel technologies, capable of printing raw materials from pellets and also of heating the receiving support or substrate, 9 are now on the market. It has therefore many advantages compared to the technology using filaments, and this technique was used in this work.…”

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confidence: 99%

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Additive manufacturing of fire‐retardant ethylene‐vinyl acetate

Geoffroy

Samyn

Jimenez

et al. 2019

Polymers for Advanced Techs

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Thermocompression (with also extrusion and injection molding) is a classical polymer shaping manufacturing, but it does not easily allow designing sophisticated shapes without using a complex mold, on the contrary to 3D printing (or polymer additive manufacturing), which is a very flexible technique. Among all 3D printing techniques, fused deposition modeling is of high potential for product manufacturing, with the capability to compete with conventional polymer processing techniques. This is a quite low cost 3D printing technique, but the range of filaments commercially available is limited. However, in some specific 3D printing processes, no filaments are necessary. Polymers pellets feed directly the printing nozzle allowing to investigate many polymeric matrices with no commercial limitation. This is of high interest for the design of flame‐retarded materials, but literature is scarce in that field. In this paper, a comparison between thermocompression and 3D printing processes was performed on both neat ethylene‐vinyl acetate (EVA) copolymer and EVA flame retarded with aluminum triHydroxyde (ATH) containing different loadings (30 or 65 wt%) and with expandable graphite (EG), ie, EVA/ATH (30 wt%), EVA/ATH (65 wt%), and EVA/EG (10 wt%), respectively. Morphological comparisons, using microscopic and electronic microprobe analyses, revealed that 3D printed plates have lower apparent density and higher porosity than thermocompressed plate. The fire‐retardant properties of thermocompressed and 3D printed plates were then evaluated using mass loss calorimeter test at 50 kW/m2. Results highlight that 3D printing can be used to produce flame‐retardant systems. This work is a pioneer study exploring the feasibility of using polymer additive manufacturing technology for designing efficient flame‐retarded materials.

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“…However, the predictions for melt pool peak temperature, y 3 , show a higher value of MAPE (12% of the simulation range) compared to the predictions for melt pool depth and width. We believe that this is due to the inherent high uncertainty associated with experimental temperature measurements using contactless temperature measurement through pyrometry [71]. The uncertainty in the temperature data can be measured by computing its standard deviation.…”

Section: Prediction Using the Calibrated Modelmentioning

confidence: 99%

Multivariate Calibration and Experimental Validation of a 3D Finite Element Thermal Model for Laser Powder Bed Fusion Metal Additive Manufacturing

Mahmoudi

Tapia

Karayagiz

et al. 2018

Integr Mater Manuf Innov

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Metal additive manufacturing (AM) typically suffers from high degree of variability in the properties/performance of the fabricated parts, particularly due to the lack of understanding and control over the physical mechanisms that govern microstructure formation during fabrication. This paper directly addresses an important problem in AM: the determination of the thermal history of the deposited material. Any attempts to link process to microstructure in AM would need to consider the thermal history of the material. In-situ monitoring only provides partial information and simulations may be necessary to have a comprehensive understanding of the thermo-physical conditions to which the deposited material is subjected. We address this in the present work through linking thermal models to experiments via a computationally efficient surrogate modeling approach based on multivariate Gaussian processes (MVGPs). The MVGPs are then used to calibrate the free parameters of the multi-physics models against experiments, sidestepping the use of prohibitively expensive Monte Carlo-based calibration. This framework thus makes it possible to efficiently evaluate the impact of varying process parameter inputs on the characteristics of the melt pool during AM. We demonstrate the framework on the calibration of a thermal model for Laser-Powder Bed Fusion AM of Ti-6Al-4V against experiments carried out over a wide window in the process parameter space. While this work deals with problems related to AM, its applicability is wider as the proposed framework could potentially be used in many other ICME-based problems where it is essential to link expensive computational materials science models to available experimental data.

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Process defects andin situmonitoring methods in metal powder bed fusion: a review

Cited by 617 publications

References 115 publications

A Review of the As-Built SLM Ti-6Al-4V Mechanical Properties towards Achieving Fatigue Resistant Designs

A Review of the As-Built SLM Ti-6Al-4V Mechanical Properties towards Achieving Fatigue Resistant Designs

Additive manufacturing of fire‐retardant ethylene‐vinyl acetate

Multivariate Calibration and Experimental Validation of a 3D Finite Element Thermal Model for Laser Powder Bed Fusion Metal Additive Manufacturing

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