Improving dimensional accuracy in EBM using beam characterization and trajectory optimization

Béraud, Nicolas; Vignat, Frédéric; Villeneuve, François; Dendievel, Rémy

doi:10.1016/j.addma.2016.12.002

Cited by 21 publications

(7 citation statements)

References 20 publications

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“…After the melting step, the material is solid with virtually no porosity. Reduction in porosity results in reduced layer thickness of the melted zones, i.e., volume shrinkage and an increase of the overall layer thickness up to 80 μ m [14]. This means that a powder with particle size of 45-106 μ m is suitable for applying a layer with a theoretical thickness of 50 μ m.…”

Section: Methodsmentioning

confidence: 99%

The Effect of EBM Process Parameters on Porosity and Microstructure of Ti-5Al-5Mo-5V-1Cr-1Fe Alloy

et al. 2019

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In this article, the authors discuss the results of studies into the processing of Ti-5Al-5Mo-5V-1Cr-1Fe near-β titanium alloy (Ti-55511) by electron beam melting (EBM), an additive manufacturing technique. Due to its high flexibility in shaping mechanical properties, Ti-55511 alloy is commonly used in aircraft components such as landing gear or airframes. In this study, Ti-55511 powder was used and its properties were described as regards chemical composition and particle size distribution in order to assess its suitability for EBM processing and repeatability of results. 20 sets of processing parameters were tested in the energy input range between 10 J/mm3 and 50 J/mm3 (cathode current, 4.5 mA-19.5 mA; scanning speed, 1080 mm/s–23400 mm/s). Four types of top surfaces were obtained, namely, flat, orange peel, with single pores, and with swelling. Best results were obtained for the energy of 30 J/mm3: flat top surface and relative density in excess of 99.9%. Analysis of chemical composition showed that aluminum loss was below the specification minimum for the analyzed parameter sets. Scanning speed most significantly affected aluminum content: the lower the scanning speed, the higher the aluminum loss. Analysis of microstructures showed the dependence of lamellar α-phase volume fraction on the process parameters used. For low scanning speed, the determined α-phase volume accounted for about 78%. Higher scanning speed resulted in a decrease of the α-phase content to 61%. The dimensions of the lamellas and the amount of the α-phase strongly effected hardness results (360 HV to 430 HV).

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Section: Methodsmentioning

confidence: 99%

The Effect of EBM Process Parameters on Porosity and Microstructure of Ti-5Al-5Mo-5V-1Cr-1Fe Alloy

et al. 2019

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“…Béraud et al worked on the finite element modeling (FEM) and simulated the process to see the effect of process parameters on the parts. Using appropriate process parameters, the dimensional accuracy can be improved by 60 per cent (Béraud et al, 2017).…”

Section: Challengesmentioning

confidence: 99%

Review on electron beam based additive manufacturing

Negi

Nambolan

Kapil

et al. 2019

RPJ

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Purpose Electron beam-based additive manufacturing (EBAM) is an emerging technology to produce metal parts layer-by-layer. The purpose of this paper is to systematically address the research and development carried out for this technology, up till now. Design/methodology/approach This paper identifies several aspects of research and development in EBAM. Findings Electron beam has several unique advantages such as high scanning speed, energy efficiency, versatility for several materials and better part integrity because of a vacuum working environment. Originality/value This paper provides information on different aspects of EBAM with the current status and future scope.

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“…Truss dimension accuracy and repeatability can be improved to a certain extent with optimised SLM process parameters. The influences of process parameters on part quality are determined for fine-tuning and optimisation via a generally costly experimental test matrix [27][28] [29]. Still, process optimisation cannot fully eliminate geometric imperfections due to inherent process limitations.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the optimised parameters are generally applied for all trusses; the overhang angle, size and shape dependency therefore cannot be considered. In addition, with optimised process parameters the printed trusses still show deviations from the as-designed geometry for larger overhang angles, such as non-circular cross-sections, due to the penetration of the heat source into the layers below the current build layer [27].…”

Section: Introductionmentioning

confidence: 99%

Artificial neural network-based geometry compensation to improve the printing accuracy of selective laser melting fabricated sub-millimetre overhang trusses

Hong

Zhang

Lifton³

et al. 2021

Additive Manufacturing

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Selective laser melting processes deposit and join metal powders to near net shape in a layerby-layer manner. The process of melting and re-solidification of several layers of deposited material can result in geometric deviations, and the impact is particularly significant for submillimetre structures oriented at a wide range of overhang angles with respect to the building platform. This paper assesses and benchmarks the capabilities of a neural network-based geometric compensation approach for truss lattice structures with circular cross-sections. The neural network method is capable to generate free-form cross-sections with enhanced geometric freedom for compensation compared to more established analytical compensation approaches limited to predefined geometric shapes. For neural network training, lattice dome structures composed of trusses with different overhang angles were designed and printed by selective laser melting and measured via X-ray computed tomography, resulting in point cloud data sets containing more than 20,000 data points for each overhang angle. For experimental validation, neural network-compensated dome structures were benchmarked against dome structures with elliptical parameter compensation. Results show that the neural network compensated lattice trusses achieve higher printing dimensional accuracy compared to the uncompensated structures and those compensated based on elliptical parameter estimates.

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Improving dimensional accuracy in EBM using beam characterization and trajectory optimization

Cited by 21 publications

References 20 publications

The Effect of EBM Process Parameters on Porosity and Microstructure of Ti-5Al-5Mo-5V-1Cr-1Fe Alloy

The Effect of EBM Process Parameters on Porosity and Microstructure of Ti-5Al-5Mo-5V-1Cr-1Fe Alloy

Review on electron beam based additive manufacturing

Artificial neural network-based geometry compensation to improve the printing accuracy of selective laser melting fabricated sub-millimetre overhang trusses

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