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.

X-Ray CT Investigation of Graded Ti-Ti64 Material Produced by Selective Laser Melting

2019 ◽  
Vol 822 ◽  
pp. 542-548
Author(s):  
Vadim Sufiiarov ◽  
Artem Kantyukov ◽  
Igor A. Polozov
Keyword(s):  
Computed Tomography ◽  
Selective Laser Melting ◽  
Hot Isostatic Pressing ◽  
Laser Melting ◽  
Raw Data ◽  
X Ray ◽  
Isostatic Pressing ◽  
Volume Graphics ◽  
X Ray Computed

This paper is devoted to the study of gradient samples of Ti-Ti64 material, manufactured by selective laser melting. The measurements of porosity, differences in densities are made with x-ray computed tomography for as-processed and after hot isostatic pressing samples. The raw data was processed using the software Volume Graphics and AVIZO. The porosity of the samples was studied and their sphericity was calculated.

In Implementing a Metal 3D AM Machine

2018 ◽  
Vol 786 ◽  
pp. 356-363
Author(s):  
Tero Jokelainen ◽  
Kimmo Mäkelä ◽  
Aappo Mustakangas ◽  
Jari Mäkelä ◽  
Kari Mäntyjärvi
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Dimensional Accuracy ◽  
Acceptance Test ◽  
Aisi 316L ◽  
Laser Melting ◽  
Geometrical Accuracy ◽  
Machine Performance ◽  
Geometrical Features ◽  
Made In

Additive Manufacturing (AM) does not yet have a standardized way to measure performance. Here a AM machines dimensional accuracy is measured trough acceptance test (AT) and AM machines capability is tested trough test parts. Test parts are created with specific geometrical features using a 3D AM machine. Performance of the machine is then evaluated trough accuracy of test parts geometry. AM machine here uses selective laser melting (SLM) process. This machine has done Factory acceptance test (FAT) to ascertain this machine ́s geometrical accuracy with material AISI 316L. Manufacturer promises accuracy of ±0.05 mm. These parts are used as comparison to AT parts made in this study. After installation two AT parts are manufactured with AM machine. One with AISI 316L and one AlSi10Mg. Dimensional accuracy of geometrical features on these parts are then compared to FAT part and to one another. Machines capability is measured trough two test parts done with material AlSi10Mg. Two of the test parts are done at the same time using same model as the FAT. Parts are printed without supports and with features facing same directions. Features of these parts were then evaluated. Another test to find out AM machines capability was to create part consisting of pipes doing 90˚ angle resulting in horizontal and vertical holes. Dimensional accuracy and circularity of holes was measured. Through these tests machines capability is benchmarked.

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 Repeatability and Reproducibility Assessment of a PolyJet Technology Using X-ray Computed Tomography

2020 ◽  
Vol 10 (20) ◽  
pp. 7040
Author(s):  
Ana Pilipović ◽  
Gorana Baršić ◽  
Marko Katić ◽  
Maja Rujnić Havstad
Keyword(s):  
Computed Tomography ◽  
Dimensional Accuracy ◽  
Test Plate ◽  
X Ray ◽  
Small Series ◽  
Measurement Results ◽  
Shape Errors ◽  
X Ray Computed ◽  
Repeatability And Reproducibility ◽  
Dimensional Errors

From the very start of their use until today, processes in Additive Manufacturing (AM) have found a way to grow from prototype production to individual and small-series production. Improvements in machinery, materials and other challenges in AM development have improved product quality, its mechanical properties and dimensional accuracy. Research in the field of dimensional accuracy must be focused on achieving better tolerances. From the beginning of AM, there has been a big issue in assuring dimensional repeatability and reproducibility of a part being printed over the course of several days. In order to examine that, a test plate was designed and built repeatedly with PolyJet technology over the course of several weeks. Measurements of dimensional accuracy and shape deviations of several typical features were carried out using X-ray Computed Tomography. Measurement results were analysed and presented in order to indicate the repeatability and reproducibility of PolyJet AM technology. Results show that PolyJet technology consistently produces parts within ±100 μm, at a 95% confidence interval, under reproducibility conditions of over a 1-month period. Accuracy for measurands (distance) in the x and y axis was significantly better than it was for the z axis which was from 56 to 197 µm, i.e., in the x and y axis, it was from −8 to 76 µm. Shape errors (i.e., cylindricity) were larger than positional or dimensional errors; this can be attributed to relatively large surface roughness and small feature sizes on the test plate that was used.

Additive manufacturing of CMSX-4 Ni-base superalloy by selective laser melting: Influence of processing parameters and heat treatment

2019 ◽  
Vol 30 ◽  
pp. 100874 ◽  
Author(s):  
Inmaculada Lopez-Galilea ◽  
Benjamin Ruttert ◽  
Junyang He ◽  
Thomas Hammerschmidt ◽  
Ralf Drautz ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Processing Parameters ◽  
Laser Melting ◽  
Base Superalloy

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

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