A method to determine the depowdered height in lattices manufactured by electron beam melting

Carré, Aurélien; Museau, Matthieu; Doutre, Pierre-Thomas; Vignat, Frédéric

doi:10.1016/j.jmapro.2018.05.025

Cited by 15 publications

(6 citation statements)

References 12 publications

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“…EBM technology makes it possible to manufacture lattice structures [1], [20]. Past researches recommend a minimum radius of 0.4 mm [20] and provide a depowderable criteria [21] [22] in accordance with the manufacturability. For each set of parameters, three samples are designed for a total of 15 structures to be fabricated.…”

Section: Multipipe Tools In Rhino Grasshoppermentioning

confidence: 99%

Influence of fillets onto mechanical properties of octet-truss lattice structures

Doutre,

Grandvallet,

Gobet

et al. 2023

Preprint

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The development of Additive Manufacturing (AM) for the fabrication of metallic parts allows structures to be directly manufactured from 3D models. The Electron Beam Melting (EBM) technology is an example of AM technologies that enables the manufacturing of new designs and sophisticated geometries. The process is particularly well suited for the fabrication of lattice structures. Octet-truss lattice structure has been a subject for research during the past 10 years. The potentials that it possesses attract enough interest for manufacturers to use it during the production of parts. Besides being lightweighted, the structure could provide solid mechanical properties. However, researchers always encounter the same issue regarding this particular structure. During Finite Element Analysis (FEA) simulation, stress concentration tends to appear at the struts intersection. This is due to the sharp edges that have very small surface area, thus provoking the presence of singularities. In this respect, the proposed solution is to integrate rounded-joints or fillets at the struts intersection. However, adding fillet entails a mass increase of octet-truss structures. To avoid this mass increase related to these fillets, it is necessary to reduce the size of octet-truss struts. This research work studies the influence of fillets onto the mechanical properties of structures with identical mass. To do so, a set of 15 octet-truss structures are designed with various fillet sizes and strut sizes and compared. Whereas some of them have thick struts and small fillets, others have smaller struts and bigger fillets. The main technical issue in this study remains the design of fillets for octet-truss structures. These latter can indeed be created for up to 12 struts that converge to the same point. Once designed, these octet-truss structures are fabricated by EBM technology and undergo static compression testing. Mechanical properties of each structure are finally determined. Results show that for the same relative density, octet-truss with fillets degrades the mechanical characteristics of the whole structures. This study shows that the strength/mass ratio is better for a structure without fillets. this result can be used in lightweighted applications.

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Section: Multipipe Tools In Rhino Grasshoppermentioning

confidence: 99%

Influence of fillets onto mechanical properties of octet-truss lattice structures

Doutre,

Grandvallet,

Gobet

et al. 2023

Preprint

Self Cite

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“…Other latest researches have also been carried out by Carre et al [9] who predict the depowdering capacity of lattice structures based on hydraulic diameter. All these approaches characterize the ability to depowder by implementing a PRS [7], but little is described about other working approaches.…”

Section: State Of the Artmentioning

confidence: 99%

“…From an industry point of view, to enhance the depowdering system of EBM technology will have high beneficial effect. For instance, it could be interesting to make mono-bloc heat exchangers that contains conformal cooling channels, or else, to build lattice structures with a density above the boundaries highlighted by [9]. To do so, additional research work would be required for tackling needs such as to determine the depowdering limits for parts with internal complex shapes or to extend the method to a depowdering device with bigger dimensions.…”

Section: Perspectivesmentioning

confidence: 99%

A new method with ultrasonic mechanism for efficient depowdering of parts produced by electron beam melting

Doutre

Grandvallet

Museau

2022

Mechanics & Industry

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Among metallic additive manufacturing technologies, electron beam melting (EBM) requires a specific operation called depowdering once a part is built. With the help of a powder recovery system (PRS), this process consists in blowing titanium powder onto a “cake” of a manufactured part in order to separate sintered but not melted powder from the part itself. However, the depowdering of some geometries can in fact become difficult, even impossible, due to the part shape. This article aims at proposing an ultrasonic depowdering mechanism that allows to improve and to quantify the depowdering capabilities of the PRS system currently used. Experimentations are led onto geometries that include canals. A “depowderable depth”/diameter criterion is then applied for comparing the depowdering capacity of the proposed system with the traditional one. First results show that the quantity of powder removed onto samples is highly enhanced with an ultrasonic process. This outcome creates opportunities since additional tests could be implemented onto more complex shapes such as, for instance, parts with internal complex shapes.

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“…Mostly, it is assumed that the determined physical values can be directly correlated to the actual fatigue state and, thus, the damage progress. However, a complex interaction of signals has been revealed [23] such that a simultaneous application of several measuring techniques should be considered. In the literature [53,54], the combination of these techniques has been successfully applied for the detailed evaluation of the fatigue behavior of various steels and lightweight alloys.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

“…In the aforementioned study the authors concluded that the relationship between cycles to failure and fatigue strength follows a power law; in particular, the influence of specific aspects like relative density and cell topology were highlighted. However, little work regarding the mechanical properties of lattice structures manufactured by E-PBF has been carried out so far [23,24].…”

Section: Introductionmentioning

confidence: 99%

Damage Tolerance Evaluation of E-PBF-Manufactured Inconel 718 Strut Geometries by Advanced Characterization Techniques

et al. 2020

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By means of electron beam powder bed fusion (E-PBF), highly complex lightweight structures can be manufactured within short process times. Due to the increasing complexity of producible components and the entangled interplay of damage mechanisms, common bulk material properties such as ultimate tensile or fatigue strength are not sufficient to guarantee safe and reliable use in demanding applications. Within this work, the damage tolerance of E-PBF-manufactured Ni-based alloy Inconel 718 (IN 718) strut geometries under uniaxial cyclic loading was investigated supported by several advanced measurement techniques. Based on thermal and electrical measurements, the failure of single struts could reliably be detected, revealing that continuous monitoring is applicable for such complex geometries. Process-induced surface roughness was found to be the main reason for early failure during cyclic loading. Thus, adequate post-processing steps have to be established for complex geometries to significantly improve damage tolerance and, eventually, in-service properties.

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A method to determine the depowdered height in lattices manufactured by electron beam melting

Cited by 15 publications

References 12 publications

Influence of fillets onto mechanical properties of octet-truss lattice structures

Influence of fillets onto mechanical properties of octet-truss lattice structures

A new method with ultrasonic mechanism for efficient depowdering of parts produced by electron beam melting

Damage Tolerance Evaluation of E-PBF-Manufactured Inconel 718 Strut Geometries by Advanced Characterization Techniques

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