scholarly journals A multi-technique tomography-based approach for non-invasive characterization of additive manufacturing components in view of vacuum/UHV applications: preliminary results

2021 ◽  
Author(s):  
Francesco Grazzi ◽  
Carlo Cialdai ◽  
Marco Manetti ◽  
Mirko Massi ◽  
Maria Pia Morigi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Additive Manufacturing ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Proton Accelerator ◽  
Neutron Tomography ◽  
Metallic Component ◽  
X Ray ◽  
Building Orientation ◽  
X Ray Computed

AbstractIn this paper, we have studied an additively manufactured metallic component, intended for ultra-high vacuum application, the exit-snout of the MACHINA transportable proton accelerator beam-line. Metal additive manufacturing components can exhibit heterogeneous and anisotropic microstructures. Two non-destructive imaging techniques, X-ray computed tomography and Neutron Tomography, were employed to examine its microstructure. They unveiled the presence of porosity and channels, the size and composition of grains and intergranular precipitates, and the general behavior of the spatial distribution of the solidification lines. While X-ray computed tomography evidenced qualitative details about the surface roughness and internal defects, neutron tomography showed excellent ability in imaging the spatial density distribution within the component. The anisotropy of the density was attributed to the material building orientation during the 3D printing process. Density variations suggest the possibility of defect pathways, which could affect high vacuum performances. In addition, these results highlight the importance of considering building orientation in the design for additive manufacturing for UHV applications. Graphical Abstract

scholarly journals Effect of Porosity on Mechanical Properties of 3D Printed Polymers: Experiments and Micromechanical Modeling Based on X-Ray Computed Tomography Analysis

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1154 ◽  
Author(s):  
Wang ◽  
Zhao ◽  
Fuh ◽  
Lee
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Micromechanical Model ◽  
Micromechanical Modeling ◽  
X Ray ◽  
Fused Deposition ◽  
3D Printed ◽  
X Ray Computed

Additive manufacturing (commonly known as 3D printing) is defined as a family of technologies that deposit and consolidate materials to create a 3D object as opposed to subtractive manufacturing methodologies. Fused deposition modeling (FDM), one of the most popular additive manufacturing techniques, has demonstrated extensive applications in various industries such as medical prosthetics, automotive, and aeronautics. As a thermal process, FDM may introduce internal voids and pores into the fabricated thermoplastics, giving rise to potential reduction on the mechanical properties. This paper aims to investigate the effects of the microscopic pores on the mechanical properties of material fabricated by the FDM process via experiments and micromechanical modeling. More specifically, the three-dimensional microscopic details of the internal pores, such as size, shape, density, and spatial location were quantitatively characterized by X-ray computed tomography (XCT) and, subsequently, experiments were conducted to characterize the mechanical properties of the material. Based on the microscopic details of the pores characterized by XCT, a micromechanical model was proposed to predict the mechanical properties of the material as a function of the porosity (ratio of total volume of the pores over total volume of the material). The prediction results of the mechanical properties were found to be in agreement with the experimental data as well as the existing works. The proposed micromechanical model allows the future designers to predict the elastic properties of the 3D printed material based on the porosity from XCT results. This provides a possibility of saving the experimental cost on destructive testing.

scholarly journals X-ray computed tomography and additive manufacturing in medicine: a review

2017 ◽  
Vol 8 ◽  
pp. 17 ◽  
Author(s):  
Adam Thompson ◽  
Donal McNally ◽  
Ian Maskery ◽  
Richard K. Leach
Keyword(s):  
Computed Tomography ◽  
Additive Manufacturing ◽  
X Ray ◽  
X Ray Computed

X-Ray Computed Tomography Inspection in Metal Additive Manufacturing: The Role of Witness Specimens

2020 ◽  
pp. 139-156
Author(s):  
Anton du Plessis ◽  
Jess M. Waller ◽  
Stephan G. le Roux ◽  
Ina Yadroitsava ◽  
Igor Yadroitsev ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Additive Manufacturing ◽  
X Ray ◽  
Metal Additive Manufacturing ◽  
X Ray Computed ◽  
Metal Additive

Measurement of the Porosity of Additive-Manufactured Al-Cu Alloy Using X-Ray Computed Tomography

2016 ◽  
Vol 258 ◽  
pp. 448-451 ◽  
Author(s):  
Aneta Zatočilová ◽  
Tomáš Zikmund ◽  
Jozef Kaiser ◽  
David Paloušek ◽  
Daniel Koutný
Keyword(s):  
Computed Tomography ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Dimensional Accuracy ◽  
Threshold Value ◽  
Processing Parameters ◽  
Laser Melting ◽  
X Ray ◽  
X Ray Computed ◽  
Metallic Parts

The additive manufacturing of metallic parts by means of selective laser melting is an emerging technology, the development of which is currently of great interest. The quality of the parts produced is evaluated mainly in terms of their mechanical properties, dimensional accuracy, and the homogeneity of the material. Because it is virtually impossible to produce parts without any internal porosity using powder-based additive manufacturing processes, measuring the porosity is critically important to optimizing the processing parameters. X-ray computed tomography is currently the only way used to measure the distribution of pores non-destructively and it can also measure the density and dimensional accuracy. Many studies have presented results of porosity measurements made using CT, but no standard methodology for the making of measurements and processing of data currently exists. The choice of parameters used for measurement and processing can have a significant impact on the results. This study focuses on the effect of voxel resolution on the resulting porosity number and discusses the possibilities for determining the threshold value for detecting pores. All the results presented in this study were obtained by analyzing the sample produced by selective laser melting technology from AlCu2Mg1.5Ni alloy.

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