Power Density Distribution for Laser Additive Manufacturing (SLM): Potential, Fundamentals and Advanced Applications

Metel, Alexander; Stebulyanin, M. M.; Fedorov, S. Yu.; Okunkova, Anna A.

doi:10.3390/technologies7010005

Cited by 53 publications

(35 citation statements)

References 92 publications

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“…The significant difference between the ceramics was in the conditions of production. The first sample was produced in the laboratories of MSTU STANKIN with the maximum achievable homogeneity of powders before hybrid sintering [59]. The main SPS parameters are presented in Table 5 [123,124].…”

Section: Methodsmentioning

confidence: 99%

“…Then, a research group under the supervision of Prof. Torrecillas and Prof. Moya proposed an advanced SPS method assisted by electrical current to produce new nanocomposites of Al 2 O 3 +SiC w +TiC. In addition, the question of the percolation threshold and the achieved electrical and mechanical properties of samples were discussed [57, 58, 59]. Note that having a suitable conductivity for EDM and attaining precise machining are two different things.…”

Section: Introductionmentioning

confidence: 99%

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Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Grigoriev

Kozochkin

Porvatov

et al. 2019

Heliyon

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The productivity of electrical discharge machining (EDM) is relatively low owing to the natural laws of electrical erosion. Precise EDM demands uninterrupted control of the discharge gap and adjustment of process parameters. It is particularly critical for processing large workpieces with complex linear surfaces and for materials with threshold conductivities such as the new advanced ceramic nanocomposites Al2O3+TiC and Al2O3+SiCw+TiC(30–40%). In these cases, adequate flushing of erosion products is hampered by the geometry of the working space or by the small value of the required discharge gap, which does not exceed 2.2–2.5 μm. The methods of adaptive control in modern computer numerical control systems of EDM equipment based on measuring the electrical parameters in the working zone have been shown to be ineffective in the cases described above. This study aims to investigate the natural phenomena of material sublimation under discharge pulses for conductive ceramics and nanocomposites. The measured conductivities of the samples are higher than the percolation threshold. However, the question of machinability remains open owing to detected processing interruptions and poor quality of machined surfaces. New knowledge on EDM of conductive ceramics and nanocomposites can improve the final quality of the machined surfaces and productivity of the method by the introduction of advanced monitoring and control methods based on acoustic emissions. The manuscript presents an up-to-date overview and current state of the research on the subject area. The obtained morphology of the samples and discussion of the findings complete the experimental part of the study. The scientific basis for a new type of adaptive control system is provided. This can improve the effectiveness of parameter control for machining conductive ceramics and nanocomposites and contribute to an increase in the EDM performance for the most critical cases.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Grigoriev

Kozochkin

Porvatov

et al. 2019

Heliyon

View full text Add to dashboard Cite

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“…The difference observed between the two setups might be linked to the energy distribution of the laser beam (Gaussian versus top-hat). (Metel et al, 2018) studied the influence of the laser power distribution for L-PBF single beads of a CoCrMo alloy including Gaussian, top hat and donut distributions. Even if they observed globally similar denuded widths with Gaussian or top hat laser distributions, the (denuded width/ laser diameter) ratio was two times larger for the Gaussian beam diameter.…”

Section: Comparison Of the Two Setupsmentioning

confidence: 99%

Influence of gas atmosphere (Ar or He) on the laser powder bed fusion of a Ni-based alloy

Traore

Schneider

Koutiri

et al. 2021

Journal of Materials Processing Technology

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The gaseous atmosphere plays a major role in the quality of the manufactured parts in Laser Powder Bed Fusion (L-PBF) by protecting the metal from high temperature oxidation. If argon and nitrogen are the most commonly used gases, helium has almost never been considered as a possible candidate as a chemically inert shielding gas. To provide a better understanding of the influence of the gas atmosphere on the process stability, a comparative study of L-PBF manufacturing under argon and helium atmospheres has been carried out, considering a nickelbased alloy Inconel® 625 and a single bead configuration. To this end, in-situ process measurements were carried out on a dedicated experimental setup. The melt pool behaviour, the expansion of the vapour plume and the amount of spatters were evaluated with high-speed imaging for the two gases considered, together with the final L-PBF bead dimensions. Results were also compared to single fusion beads carried out in an industrial L-PBF machine for a comparable range of volume energy densities. The influence of the shielding atmosphere on L-PBF single beads was as follows: (1) dimensions of beads were shown to be constant whatever the gas; (2) fewer and smaller spatters were produced under helium atmosphere, especially for high volume energy densities. Physical mechanisms were then discussed to understand those specific effects.

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“…The research activity on AM is mainly focused on the melting/sintering process, neglecting the spreading of the powders to build the powder bed. The most commonly considered features are the scan strategy, the characteristics of the powders, and the parameters of the heat source [ 4 ]. However, the characteristics of the powder bed (e.g., the packing factor, its homogeneity within the powder layer, and the actual layer thickness) strongly influence the printing process and must be carefully taken into account.…”

Section: Introductionmentioning

confidence: 99%

Discrete Element Method Analysis of the Spreading Mechanism and Its Influence on Powder Bed Characteristics in Additive Manufacturing

2021

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Laser powder bed fusion additive manufacturing is among the most used industrial processes, allowing for the production of customizable and geometrically complex parts at relatively low cost. Although different aspects of the powder spreading process have been investigated, questions remain on the process repeatability on the actual beam–powder bed interaction. Given the influence of the formed bed on the quality of the final part, understanding the spreading mechanism is crucial for process optimization. In this work, a Discrete Element Method (DEM) model of the spreading process is adopted to investigate the spreading process and underline the physical phenomena occurring. With parameters validated through ad hoc experiments, two spreading velocities, accounting for two different flow regimes, are simulated. The powder distribution in both the accumulation and deposition zone is investigated. Attention is placed on how density, effective layer thickness, and particle size distribution vary throughout the powder bed. The physical mechanism leading to the observed characteristics is discussed, effectively defining the window for the process parameters.

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Power Density Distribution for Laser Additive Manufacturing (SLM): Potential, Fundamentals and Advanced Applications

Cited by 53 publications

References 92 publications

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

Influence of gas atmosphere (Ar or He) on the laser powder bed fusion of a Ni-based alloy

Discrete Element Method Analysis of the Spreading Mechanism and Its Influence on Powder Bed Characteristics in Additive Manufacturing

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