Denudation of metal powder layers in laser powder bed fusion processes

Matthews, Manyalibo J.; Guss, Gabe; Khairallah, Saad A.; Rubenchik, Alexander M.; Depond, Philip J.; King, Wayne E.

doi:10.1016/j.actamat.2016.05.017

Cited by 619 publications

(233 citation statements)

References 17 publications

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“…The irregularities can be correlated with how the particles were arranged; leading to non-uniform capillary forces on both sizes of the laser track. This behaviour is in agreement with high speed camera images reported in literature [11,12].…”

Section: Resultssupporting

confidence: 81%

Influence of Powder Bed Characteristics on Material Quality in Additive Manufacturing

Zielinski

Vervoort

Mindt

et al. 2017

Berg Huettenmaenn Monatsh

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Abstract:In powder bed based Additive Manufacturing (AM) processes like Selective Laser Melting (SLM) or Electron Beam Melting (EBM), the spatial distribution of the individual powder particles is typically unknown. Nevertheless, the distribution of particles in the heat affected zone defines the thermophysical properties of the region being processed by the heat source and therefore plays a crucial role in heat transfer processes. In this work, the spatial distribution of individual particles and their influence on the AM process is numerically investigated. Two powder bed configurations are compared: One powder bed is generated using the discrete element method (DEM) to model the coating process; the second powder bed is arranged in the BCC structure. The melting and solidification of both configurations are modelled. The predicted melt pool dimensions are compared with experimentally determined values. The results indicate that modelling the coating process is necessary to ensure accurate modelling of the heat source powder bed interaction as well as an accurate prediction of the melt pool characteristics. Keywords

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Section: Resultssupporting

confidence: 81%

Influence of Powder Bed Characteristics on Material Quality in Additive Manufacturing

Zielinski

Vervoort

Mindt

et al. 2017

Berg Huettenmaenn Monatsh

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“…These results also confirm the overall influence of vaporization phenomena already mentioned by all the recent works carried out in Livermore Lab. (King et al, 2014;Matthews et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…3 and 4) can be summarized as follows: (1) due to conduction heating of the surrounding powder bed, powder grains in close contact with the upper and lateral side of melt-pool tend to agglomerate to form larger liquid droplets, (2) For low VED values, such droplets are incorporated to the MP whereas above a VED threshold generating more or less intense vaporization, a possible key-hole regime and accelerated liquid flow backwards, such droplets are accelerated sheared upwards by the metallic gas plume and ejected. The mechanisms for lateral attraction of liquid droplets or solid grains to the melt-pool by Bernoulli-like effects are detailed by Matthews et al (2016).…”

Section: Generation Of Spattersmentioning

confidence: 99%

“…In a preliminary work by King et al (2014), the threshold for key-hole formation, assumed to be a major contributor to the formation of defects, was calculated by considering the depth variation versus a normalized enthalpy value. The experimental and numerical work detailed in Matthews et al (2016) focused on the denudation phenomena occurring near SLM beads and concluded that inward lateral gas flow induced by the melt-pool vaporization was the main dragging force for powder depletion. Khairallah et al (2016) also considered key-hole closure as a possible explanation for porosity formation, and confirmed that melt-pool vaporization was a key factor for the formation of spatters and denudation.…”

Section: Introductionmentioning

confidence: 99%

“…Investigations on single beads have been previously carried out by many authors such as Yadroitsev et al (2010), King et al (2014), Khairallah et al (2016) and Matthews et al (2016), for investigating the physics of SLM. In the following work, single beads are considered to be representative of the first stage of a SLM process, near the platform, where the average temperature has not reached a high and stabilized level yet.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental analysis of spatter generation and melt-pool behavior during the powder bed laser beam melting process

Gunenthiram

Peyre

Schneider

et al. 2018

Journal of Materials Processing Technology

246

111

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. A B S T R A C TThe experimental analysis of spatter formation was carried out on an instrumented SLM set-up allowing the quantification of spatter ejections and possible correlation with melt-pool behavior. Considering nearly similar SLM conditions than those carried out on SLM machines, an increase of large spatters (> 80 μm) with volume energy density (VED) was clearly demonstrated on a 316L stainless steel, which was attributed to the recoil pressure applied on the melt-pool by the metal vaporization and the resulting high velocity vapor plume. In a second step, much lower spattering was shown on Al-12Si powder beds than on 316L ones. Fast camera analysis of powder beds indicated that droplet formation was mostly initiated in the powder-bed near the melt-pool interface. On Al-12 Si alloys, such droplets were directly incorporated in the MP without being ejected upwards as spatters like on 316L. Last, it was shown that a strong reduction of spattering was possible even on 316L, with the use of low VED combined with larger spots (≈0.5 mm), allowing to melt sufficiently deep layers in conduction regime and ensure adequate dilution between layers.

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Monitoring and Quality Assurance for Metal Additive Manufacturing

2021

Metal Additive Manufacturing

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Denudation of metal powder layers in laser powder bed fusion processes

Cited by 619 publications

References 17 publications

Influence of Powder Bed Characteristics on Material Quality in Additive Manufacturing

Influence of Powder Bed Characteristics on Material Quality in Additive Manufacturing

Experimental analysis of spatter generation and melt-pool behavior during the powder bed laser beam melting process

Monitoring and Quality Assurance for Metal Additive Manufacturing

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