X-ray computed tomography for additive manufacturing: a review

Abstract

Abstract. In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM.

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

“…XCT is a scanning technique used to produce threedimensional (3D) representations of an object or patient, by taking many X-ray radiographs around a rotation axis and then reconstructing a 3D model using algorithms [6][7][8].…”

“…AM in conjunction with XCT continued to be used during this time primarily for medical modelling, though usage was expanded during this period as the available imaging and production resolutions of XCT and AM improved. Owing to these improvements, XCT also began to be used as an inspection tool for industrially manufactured parts during this time [8]. Alongside the conception of the use of XCT as a part inspection tool, throughout the 1990s and early 2000s, there was continuous development of XCT and [9].…”

“…Future developments in the field will likely result in an increase of precision and accuracy in scanning and manufacturing, so as to improve the fit between guides and the patient, and ultimately the quality of the surgical output. In keeping with these likely developments, it is worth noting that as XCT has increased in use as a metrological tool [8], a number of medical authors have similarly adopted the technology beyond its ability to recreate geometries and as a medical inspection device. Examples of this include the post-operative assessment of implant positional and angular deviation compared to the intended positioning [90], and the comparison between patient XCT data and XCT scans of AM models, through calculation of the root mean square error of surface variations [80].…”

Corroborating tomographic defect metrics with mechanical response in an additively manufactured precipitation-hardened stainless steel

“…Manufacturers such as Bruker , FEI , General Electric , Nikon , Northstar , and ZEISS are growing the market through the manufacture of both industrial and laboratory scale systems which are advancing both the operating voltages and imaging resolutions available [28][29][30][31] . While limitations in the technique's application to additively fabricated structures are becoming increasingly understood 32 , few other techniques currently provide the breadth needed to provide reasonable interrogation across the many applications, sizes and material systems being investigated. As such, micro-computed tomography continues to emerge as one of the more favorable techniques for post-build inspection of additively manufactured parts and products 33,34 .…”

Porosity detection in electron beam-melted Ti-6Al-4V using high-resolution neutron imaging and grating-based interferometry

“…X-ray computed tomography (XCT) has proven valuable for observing polymer AM pores [9]. Micro X-ray CT (lXCT) offers very high spatial resolution (as low as 5 lm) for observing Ti-6Al-4V lack of fusion, keyhole, and gas porosity [10,11].…”