Reduction of incandescent spatter with helium addition to the process gas during laser powder bed fusion of Ti-6Al-4V

Pauzon, Camille Nicole Géraldine; Hoppe, Birk; Pichler, T.; Goff, Sophie Dubiez-Le; Forêt, Pierre; Nguyen, Tri H.; Hryha, Eduard

doi:10.1016/j.cirpj.2021.07.004

Cited by 32 publications

(5 citation statements)

References 20 publications

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“…The influence of the current processing atmosphere on the metal vaporization process is as follows: S. Traore et al [ 166 ] investigated the effect of the processing atmosphere on metal vaporization during LPBF, established the processing atmospheres of argon and helium, observed the state of the melt pool, vapor plume, and sputtering during LPBF of nickel-based alloys using high-speed visible imaging, and found that changing the gas atmosphere from argon to helium can affect the melt pool and vapor plume morphology as shown in Figure 34 . C. Pauzon et al [ 167 ] used high-speed shadowing imaging to image the LPBF process in the presence of pure argon, pure helium, and a mixture of argon and helium and found that pure helium reduced spatter by at least 60% and a mixture of argon and helium reduced spatter by 30% compared to pure argon. This high-speed shadowing demonstrates the accelerated expansion of the vapor plume with the addition of helium and the reduction in spatter and vapor accumulation at the laser spot, with images taken by high-speed shadowing as shown in Figure 35 .…”

Section: Lpbf Process Inhibition Of Metal Evaporation Measuresmentioning

confidence: 99%

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Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion

et al. 2023

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Laser powder bed fusion (LPBF) is of great importance for the visual measurement and analysis of the metallization process, which is the process of solid, liquid, and gas phase transformations of metal powders under high-energy laser irradiation due to the low boiling point/high saturated vapor pressure. Since the evaporation of metals involves the interaction of driving forces such as vapor back pressure, surface tension, and gravity, the movement of the melt pool is not stable. At the same time, it also produces vaporization products such as vapor plumes and sprays, which cause defects such as bubbles, porosity, lack of fusion, inclusions, etc., during the manufacturing process of the parts, affecting the performance and manufacturing quality of the parts. More and more researchers are using imaging technologies, such as high-speed X-ray, high-speed visible light cameras, and high-speed schlieren imaging, to perform noncontact visual measurements and analyses of the melt pool, vapor plume, and spatter during the metal evaporation process, and the results show that the metal evaporation process can be suppressed by optimizing the process parameters and changing the processing atmosphere, thereby reducing part defects and improving part performance and built part quality. This paper reviews the research on metal evaporation mechanisms and visual measurement methods of metal evaporation, then discusses the measures of metal evaporation, and finally summarizes and prospects the future research hotspots of LPBF technology, according to the existing scholars’ research on numerical simulation analysis and visual measurement methods of the metal evaporation process.

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Section: Lpbf Process Inhibition Of Metal Evaporation Measuresmentioning

confidence: 99%

“… ( a ) Shadowgraphs extracted at 18,264 ms from the experiments performed under argon, the gas mixture, and helium for the no flow, negative flow, and positive flow configurations; ( b ) Analysis of the darker (colder) spatters from extracted shadowgraph [ 167 ]. …”

Section: Figurementioning

confidence: 99%

Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion

et al. 2023

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“…Although it is not possible to completely eliminate spatter, it is necessary to regulate the behavior of spatter. Currently, researchers have conducted some experimental studies on SLM spatter, and the main idea is to record the generation and motion of spatter with the help of real-time monitoring means such as high-speed cameras [7][8][9][10], X-ray imaging [11], and acoustic signal acquisition [12] and to study the effects of process parameters such as scanning speed [13], laser power [13], laser beam number [14], and the protective gas type and flow rate [15,16] on spatter behavior, and then to propose SLM spatter regulation strategies such as adjusting the forming cavity flow field [17] and adding nanoparticles [18]. Experimental studies play an important role in the in-depth understanding of SLM spatter, but because SLM spatter is in a dramatically changing high-temperature and high-speed environment, the cost of experimental studies is high, and it is difficult to achieve quantitative analysis, so numerical simulation becomes a necessary aid to research.…”

Section: Introductionmentioning

confidence: 99%

CFD–DPM Simulation Study of the Effect of Powder Layer Thickness on the SLM Spatter Behavior

Cao

Zhang

Meng

2022

Metals

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Selective Laser Melting (SLM) has significant advantages in manufacturing complex structural components and refining the alloy microstructure; however, spatter, as a phenomenon that accompanies the entire SLM forming process, is prone to problems such as inclusions, porosity, and low powder recovery quality. In this paper, a Computational Fluid Dynamics–Discrete Particle Method (CFD–DPM) simulation flow for predicting the SLM spatter behavior is established based on the open-source code OpenFOAM. Among them, the single-phase flow Navier–Stokes equation is used in the Eulerian framework to equivalently describe the effect of metal vapor and protective gas on the flow field of the forming cavity, and the DPM method is used in the Lagrangian framework to describe the metal particle motion, and the factors affecting the particle motion include particle–particle collision, particle–wall collision, fluid drag force, gravity, buoyancy force, and additional mass force. In addition, the equivalent volume force and fluid drag force are used to characterize the fluid–particle coupling interaction. For the spatter behavior and powder bed denudation phenomenon, the calculation results show that the spatter height and the drop location show a clear correlation, and the powder bed denudation phenomenon is caused by the high-speed gas flow, causing the surrounding gas to gather in the forming area, which in turn drives the motion of the powder bed particles. For the effect of powder layer thickness on spatter and powder bed denudation, the calculation results show that the effect of powder layer thickness on the number of spatters is large (when the thickness was increased from 50 μm to 100 μm, the number of spatters increased by 157%), but the effect on spatter height and drop location distribution is small. When the powder layer thickness is small, the width of the denudation zone is significantly larger, but when the powder layer reaches a certain thickness, the width of the denudation zone does not show significant changes. It should be noted that the presented model has not been directly validated by experiments so far due to the difficulty of tracking the large-scale motion of SLM spatter in real time by current experimental means.

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“…Primary components of inert gases: Pauzon et al [125] studied the effect of protective gas on L-PBF of Ti-6Al-4V powder in three different conditions: pure argon, pure helium, and a helium and argon mix (oxygen content was controlled at 100 ppm). In comparison to the common use of argon, studies have indicated that using pure helium or a mixture of helium and argon can reduce hot spatter by at least 60% and ~30%, respectively, as shown in Figure 25.…”

mentioning

confidence: 99%

“…. (2016)[124] Increase gas flow velocity (without blowing away the powder bed) Inconel 718 Ladewig et al (2016)[87] Adding helium to protective gas Ti-6Al-4V Pauzon et al (2021)[125] Printing in the central area of the powder bed Ti-6Al-4VWang et al (2021) [126] 5.1.1. Laser VED…”

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confidence: 99%

A Review of Spatter in Laser Powder Bed Fusion Additive Manufacturing: In Situ Detection, Generation, Effects, and Countermeasures

Yin

et al. 2022

Micromachines

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Spatter is an inherent, unpreventable, and undesired phenomenon in laser powder bed fusion (L-PBF) additive manufacturing. Spatter behavior has an intrinsic correlation with the forming quality in L-PBF because it leads to metallurgical defects and the degradation of mechanical properties. This impact becomes more severe in the fabrication of large-sized parts during the multi-laser L-PBF process. Therefore, investigations of spatter generation and countermeasures have become more urgent. Although much research has provided insights into the melt pool, microstructure, and mechanical property, reviews of spatter in L-PBF are still limited. This work reviews the literature on the in situ detection, generation, effects, and countermeasures of spatter in L-PBF. It is expected to pave the way towards a novel generation of highly efficient and intelligent L-PBF systems.

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Reduction of incandescent spatter with helium addition to the process gas during laser powder bed fusion of Ti-6Al-4V

Cited by 32 publications

References 20 publications

Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion

Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion

CFD–DPM Simulation Study of the Effect of Powder Layer Thickness on the SLM Spatter Behavior

A Review of Spatter in Laser Powder Bed Fusion Additive Manufacturing: In Situ Detection, Generation, Effects, and Countermeasures

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