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Industrial computed tomography (CT) scanning is any computer-aided tomographic process, usually
X-ray computed tomography An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Moti ...
, that uses
irradiation Irradiation is the process by which an object is exposed to radiation In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior th ...

irradiation
to produce three-dimensional internal and external representations of a scanned object. Industrial CT scanning has been used in many areas of industry for internal inspection of components. Some of the key uses for industrial CT scanning have been flaw detection, failure analysis, metrology, assembly analysis and
reverse engineering Reverse engineering (also known as backwards engineering or back engineering) is a process or method through the application of which one attempts to understand through deductive reasoning Deductive reasoning, also deductive logic, is the process ...

reverse engineering
applications. Just as in
medical imaging Medical imaging is the technique and process of imaging Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image). Imaging technology is the application of materi ...
, industrial imaging includes both nontomographic radiography (
industrial radiography Industrial radiography is a modality of non-destructive testing Nondestructive testing (NDT) is a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without cau ...
) and computed tomographic radiography (computed tomography).


Types of scanners

''Line beam scanning'' is the traditional process of industrial CT scanning.Hofmann, J., Flisch, A., Obrist, A., Adaptive CT scanning-mesh based optimisation methods for industrial X-ray computer tomography applications. NDT&E International (37), 2004, pp. 271–278. X-rays are produced and the beam is
collimated A collimated beam of light Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that can be visual perception, perceived by the human eye. Visible light is usually defined as having wavelength ...
to create a line. The X-ray line beam is then translated across the part and data is collected by the detector. The data is then reconstructed to create a 3-D
volume rendering In scientific visualization Surface rendering of '' confocal_microscope..html" ;"title="onfocal_microscopy.html" ;"title="pollen.html" ;"title="Arabidopsis thaliana'' Arabidopsis_thaliana''_pollen_grains_with_Confocal_microscopy">confocal ...
of the part. In ''cone beam scanning'', the part to be scanned is placed on a rotary table. As the part rotates, the cone of X-rays produce a large number of 2D images that are collected by the detector. The 2D images are then processed to create a 3D
volume rendering In scientific visualization Surface rendering of '' confocal_microscope..html" ;"title="onfocal_microscopy.html" ;"title="pollen.html" ;"title="Arabidopsis thaliana'' Arabidopsis_thaliana''_pollen_grains_with_Confocal_microscopy">confocal ...
of the external and internal geometries of the part.


History

Industrial CT scanning technology was introduced in 1972 with the invention of the
CT scanner A CT scan or computed tomography scan (formerly known as computed axial tomography or CAT scan) is a medical image, imaging Scientific technique, technique used in radiology to obtain detailed internal images of the body noninvasively for Diagno ...

CT scanner
for medical imaging by
Godfrey Hounsfield Sir Godfrey Newbold Hounsfield (28 August 1919 – 12 August 2004) was an English electrical engineer who shared the 1979 Nobel Prize for Physiology or Medicine with Allan MacLeod Cormack for his part in developing the diagnostic technique ...

Godfrey Hounsfield
. The invention earned him a Nobel Prize in medicine, which he shared with Allan McLeod Cormack. Many advances in CT scanning have allowed for its use in the industrial field for metrology in addition to the visual inspection primarily used in the medical field (medical
CT scan A CT scan or computed tomography scan (formerly known as computed axial tomography or CAT scan) is a medical image, imaging Scientific technique, technique used in radiology to obtain detailed internal images of the body noninvasively for Diagno ...

CT scan
).


Analysis and inspection techniques

Various inspection uses and techniques include part-to-CAD comparisons, part-to-part comparisons, assembly and defect analysis, void analysis, wall thickness analysis, and generation of CAD data. The CAD data can be used for
reverse engineering Reverse engineering (also known as backwards engineering or back engineering) is a process or method through the application of which one attempts to understand through deductive reasoning Deductive reasoning, also deductive logic, is the process ...

reverse engineering
, geometric dimensioning and tolerance analysis, and production part approval.


Assembly

One of the most recognized forms of analysis using CT is for assembly, or visual analysis. CT scanning provides views inside components in their functioning position, without disassembly. Some software programs for industrial CT scanning allow for measurements to be taken from the CT dataset volume rendering. These measurements are useful for determining the clearances between assembled parts or the dimension of an individual feature.


Void, crack and defect detection

Traditionally, determining defects, voids and cracks within an object would require destructive testing. CT scanning can detect internal features and flaws displaying this information in 3D without destroying the part. Industrial CT scanning (3D X-ray) is used to detect flaws inside a part such as porosity, an inclusion, or a crack. Metal casting and moulded plastic components are typically prone to porosity because of cooling processes, transitions between thick and thin walls, and material properties. Void analysis can be used to locate, measure, and analyze voids inside plastic or metal components.


Geometric dimensioning and tolerancing analysis

Traditionally, without destructive testing, full metrology has only been performed on the exterior dimensions of components, such as with a
coordinate-measuring machine A coordinate measuring machine (CMM) is a device that measures the geometry of physical objects by sensing discrete points on the surface of the object with a probe. Various types of probes are used in CMMs, including mechanical, optical, laser, an ...
(CMM) or with a vision system to map exterior surfaces. Internal inspection methods would require using a 2D X-ray of the component or the use of destructive testing. Industrial CT scanning allows for full non-destructive metrology. With unlimited geometrical complexity,
3D printing 3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. T ...
allows for complex internal features to be created with no impact on cost, such features are not accessible using traditional CMM. The first 3D printed artefact that is optimised for characterisation of form using computed tomography CT


Image-based finite element methods

Image-based finite element method converts the 3D image data from X-ray computed tomography directly into meshes for
finite element analysis The finite element method (FEM) is a widely used method for numerically solving differential equations In mathematics, a differential equation is an equation In mathematics Mathematics (from Ancient Greek, Greek: ) includes the stud ...
. Benefits of this method include modelling complex geometries (e.g. composite materials) or accurately modelling "as manufactured" components at the micro-scale.


See also

*
Industrial radiography Industrial radiography is a modality of non-destructive testing Nondestructive testing (NDT) is a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without cau ...
*
Cone beam computed tomography Cone beam computed tomography (or CBCT, also referred to as C-arm CT, cone beam volume CT, flat panel CT or Digital Volume Tomography (DVT)) is a medical imaging technique consisting of X-ray computed tomography An X-ray, or X-radiation, is ...


References

{{DEFAULTSORT:Industrial Ct Scanning Tomography
Materials science Materials science includes those parts of chemistry, physics, geology and biology that deal with the physical, chemical or biological properties of materials. It is usually considered an applied science in which the properties it studies are used ...
Microtomography Microtechnology Nondestructive testing Reverse engineering Articles containing video clips