An interlaboratory comparison of X-ray computed tomography measurement for texture and dimensional characterisation of additively manufactured parts

Townsend, Andrew; Răcăşăn, Radu; Leach, Richard; Senin, Nicola; Thompson, Adam; Ramsey, Andrew; Bate, David; Woolliams, Peter; Brown, Stephen; Blunt, Liam

doi:10.1016/j.addma.2018.08.013

Cited by 45 publications

(31 citation statements)

References 16 publications

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“…AM surface the voxel size for full characterisation should be less than one-half the surface Sa value [37]. The average value of resulted Sa of the measured acetabular cup is 5.75 µm, which is far smaller than the voxel size 31.7 µm.…”

Section: Discussionmentioning

confidence: 88%

Surface texture evaluation of additively manufactured metallic cellular scaffolds for acetabular implants using X-ray computed tomography

et al. 2019

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The surface topography of acetabular implants plays a key role in providing cell attachment and proliferation. The measurement and characterisation of the surface texture of the cellular scaffold layer on the acetabular cup are very difficult due to the 3D nature of scaffold geometry. It is proposed to use X-ray computed tomography (XCT) to measure the surface texture of an electron beam melting-produced titanium acetabular cup. The surface texture of its cellular scaffold is evaluated using the newly developed 3D surface texture parameters, which allows surface characterisation on 3D triangular mesh surfaces. Four commonly used height parameters, i.e. the arithmetical mean height Sa, the root mean square height Sq, the skewness Ssk and the kurtosis Sku, are calculated from surface patches extracted from the XCT scanned triangular mesh surface. In addition, the surface peak density and pit density, which are more related to cell communication and proliferation, are estimated based on the 3D watershed segmentation. The Wolf pruning with an empirical threshold 12 µm is used to control the over-segmentation.

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Section: Discussionmentioning

confidence: 88%

Surface texture evaluation of additively manufactured metallic cellular scaffolds for acetabular implants using X-ray computed tomography

et al. 2019

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“…Future work will include investigation of functional applications of re-entrant surfaces and their correlation to Sdr prime and Sdr mesh . Measurement accuracy for the extraction of as-built AM surface texture data from CT has been reported [11,12]. The reported work included a processing step to convert the CT mesh data to a height map (grid) format to allow direct comparison of the CT data to the reference line-of-sight focus variation instrument.…”

Section: Discussion-measurement Robustness and Evaluation Of Measuremmentioning

confidence: 99%

“…The nominal powder particle size was 45-100 µm. The methodology for the extraction of these surfaces from CT point cloud data is reported elsewhere [11,12]. Data for the extracted surfaces, including captured re-entrant features (Sdr prime and Sdr mesh ) are compared to projected (grid) data, Sdr ISO .…”

Section: Methodsmentioning

confidence: 99%

Introduction of a Surface Characterization Parameter Sdrprime for Analysis of Re-entrant Features

et al. 2019

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Producing components using metal additive manufacturing processes, such as powder bed fusion, presents manufacturing and measurement challenges, but also significant opportunities. The as-built surface may include overhanging (re-entrant) features not intentionally included in the design, but that aid in component functionality. In addition, the additive manufacturing process presents opportunities to design and manufacture re-entrant features intentionally. Re-entrant features increase the specific surface area and, in addition, produce mechanical locking to the surface. These re-entrant features may be intended to improve surface performance in areas such as biological cell attachment, coating adhesion, electrical capacitance and battery plate design, fluid flow and material cooling. Re-entrant features may prove difficult or impossible to measure and characterise using conventional line-of-sight surface metrology instrumentation, however the correct measurement of these surfaces may be vital for functional optimisation. X-ray computed tomography does have the ability to image internal and re-entrant features. This paper reports on the measurement of re-entrant features using X-ray computed tomography and the extraction of actual surface area information (including re-entrant surfaces) from sample additively manufactured surfaces. A proposed new surface texture parameter, Sdr prime , is discussed. This parameter is applicable to true 3D data, including re-entrant features, and is intended to relate directly to the component surface functional performance. The errors produced when using line-of-sight instruments and height map parameter generation per ISO 25178-2 to evaluate surfaces that include re-entrant features are discussed. Measurement results for electron beam melting and selective laser melting additively manufactured components, together with simulated structured surfaces, are presented.

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“…Another origin of porosity is the gas entrapment in the powder (during its production, leading to microporosity), or in lack of powder fusion (low laser absorption due to powder shape and/or morphology). There are several techniques to measure porosity such as Optical Microscopy (OM), Electron Microscopy (EM), X-Ray Computer Tomography (X-Ray CT) and Synchrotron Radiation Micro-Tomography (SRµT) [16,[50][51][52][53][54][55].…”

Section: Origin Of Defects and Its Inspection Methodsmentioning

confidence: 99%

Metal Additive Manufacturing Cycle in Aerospace Industry: A Comprehensive Review

Barroqueiro

Andrade‐Campos

Valente

et al. 2019

JMMP

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Additive Manufacturing (AM) is the forefront of advanced manufacturing technologies and has the potential to revolutionize manufacturing, with a dramatic change in the design and project paradigms. A comprehensive review of existent metal AM processes, processable materials, respective defects and inspection methods (destructive and non-destructive) is presented in a succinct manner. Particularly, the AM design optimization methodologies are reviewed and their threats and constraints discussed. Finally, an aerospace industry case study is presented and several cost-effective examples are enumerated.

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An interlaboratory comparison of X-ray computed tomography measurement for texture and dimensional characterisation of additively manufactured parts

Cited by 45 publications

References 16 publications

Surface texture evaluation of additively manufactured metallic cellular scaffolds for acetabular implants using X-ray computed tomography

Surface texture evaluation of additively manufactured metallic cellular scaffolds for acetabular implants using X-ray computed tomography

Introduction of a Surface Characterization Parameter Sdrprime for Analysis of Re-entrant Features

Metal Additive Manufacturing Cycle in Aerospace Industry: A Comprehensive Review

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