METHOD OF SCANNING A COMPONENT

The present disclosure provides a method of scanning a component by computed tomography, the method comprising: providing the component having a first density; supporting the component in a scanning orientation using a support bed, the support bed comprising a granular material disposed in a container, the granular material having a second density lower than the first density; wherein supporting the component comprises at least partially embedding the component in the granular material. The method further comprises scanning the component in the scanning orientation by X-ray or gamma ray scanning to produce an image of the component.

FIELD OF INVENTION

The present disclosure relates to a method of scanning a component by computed tomography.

BACKGROUND

Computed tomography (CT) scanning is an imaging technique used to obtain detailed images of a component. In particular, CT can be used to produce three-dimensional (3D) representations of a component. This may be useful for performing detailed internal inspection of the component, which may be a component of a turbomachine, such as a gas turbine engine. CT scanning can use X-rays and gamma rays to produce an image of the component. To produce a 3D model, 2D images of the component are taken from multiple angles of the component and the images are computationally combined.

The 3D model is made up of multiple voxels representing cubes in 3D space. Each voxel has a different value on the greyscale based on the opacity of the voxel. For instance, voxels indicating empty space around the component are transparent, while voxels indicating the solid body of the component are opaque. The intensity of opacity is dependent on the material property and the shape of the component.

Typically, a frame or fixture is used to hold the component in a desired orientation and position whilst it is scanned. These fixtures are typically made from a material which has a lower density than the component to be scanned, so that there is a significant difference in the opacity of the voxels of the fixture with respect to the voxels of the component in the 3D model. This enables the component to be easily distinguished from the fixture in the 3D model. These fixtures can be made from foam. However, foam fixtures only offer low strength and have only limited ability to rigidly retain the component in its desired orientation. More robust fixtures can be made using 3D printing or moulding, but have a long manufacturing time, which is undesirable.

There is therefore a need to develop a method of scanning a component which addresses at least some of the aforementioned problems.

SUMMARY

According to an aspect of the present disclosure, there is provided a method of scanning a component by computed tomography, the method comprising: providing the component having a first density; supporting the component in a scanning orientation using a support bed, the support bed comprising a granular material disposed in a container, the granular material having a second density lower than the first density; wherein supporting the component comprises at least partially embedding the component in the granular material. The method further comprises scanning the component in the scanning orientation by X-ray or gamma ray scanning to produce an image of the component.

The component may be separated from the granular material by a barrier disposed between the component and the granular material.

The barrier may have a third density which is lower than the first density.

The barrier may be formed by a casing surrounding the component.

The casing may be vacuum sealed around the component.

The support bed may further comprise a rigid support element disposed in the container. The rigid support element may have a fourth density which is lower than the first density. The rigid support element may be configured to interface with the component to retain the component at a scanning position within the container.

The container may comprise a housing enclosing the granular material. The housing may comprise a flexible wall configured to receive the component. The barrier may be formed by the flexible wall. Supporting the component may comprise positioning the component against the flexible wall to at least partially embed the component in the granular material.

The housing may further comprise a rigid wall. The flexible wall may be attached to the rigid wall.

The support element may comprise a plurality of the containers. Supporting the component may comprise arranging the component between the plurality of containers such that the component is at least partially embedded in the granular material.

The barrier may be transparent.

The granular material may be transparent.

DETAILED DESCRIPTION

With reference toFIG.1, a gas turbine engine is generally indicated at10, having a principal and rotational axis11. The engine10comprises, in axial flow series, an air intake12, a propulsive fan13, an intermediate pressure compressor14, a high-pressure compressor15, combustion equipment16, a high-pressure turbine17, an intermediate pressure turbine18, a low-pressure turbine19and an exhaust nozzle20. A nacelle21generally surrounds the engine10and defines both the intake12and the exhaust nozzle20.

The compressed air exhausted from the high-pressure compressor15is directed into the combustion equipment16where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines17,18,19before being exhausted through the nozzle20to provide additional propulsive thrust. The high17, intermediate18and low19pressure turbines drive respectively the high-pressure compressor15, intermediate pressure compressor14and fan13, each by suitable interconnecting shaft.

A component, such as a component of a gas turbine engine, may be scanned using computed tomography (CT) scanning. Here, CT scanning is defined as including scanning by X-rays or gamma rays. The component may be formed from a single material or from multiple materials. The component has an overall first material density. For example, the component may be formed from a metal.

FIG.2shows a first example of a support bed30according to the present disclosure. The support bed30comprises a granular material34disposed in a container36. The granular material34comprises a collection of discrete macroscopic particles of one or more materials. The granular material34may be a powder. The granular material34has an overall second material density, which will be referred to as the second density. By overall density is meant the mean density of the granular material taking into account any spaces between individual grains. The second density is lower than the first density of the component32. The granular material34may be any material that has a lower density than the density of the component32. For example, if the component32is formed from a metal, the granular material34may comprise a polymer, glass, foam, etc. In some examples, the granular material34may be transparent, which allows the component32to be visible when the component32is embedded in the granular material34. The container36comprises a lid38, which prevents the granular material34from escaping the container36. In other examples, the container may not comprise a lid.

In use, the component32is placed into the support bed30and manipulated within the granular material34until the component32is in a desired scanning orientation for scanning by X-ray CT. The component32is completely embedded within the granular material34, in that the component32is completely surrounded by the granular material34. In other examples, the component32may only be partially embedded in the granular material34, in that a part of the component32is not surrounded by the granular material34. The granular material34is able to support the component32in the scanning orientation. An X-ray image of the component32is then captured whilst the component32is in the scanning orientation. As the second density of the granular material34is lower than the first density of the component32, the granular material34attenuates X-rays to a lower extent than the component32. This means that the component32can be readily distinguished from the granular material34in the X-ray image. The component32can be repositioned within the granular material34such that the component32is in a different scanning orientation. As the granular material34can be readily manipulated, the component32can be moved to the different scanning orientation quickly, and the granular material34can support and retain the component32in the different scanning orientation.

FIG.3shows a second example of a support bed according to the present disclosure. The second example is substantially similar to the first example, with like reference numerals denoting like features. The second example differs from the first example only with respect to a casing covering the component.

The component32is covered by a casing35. The casing35has a third material density. The third density is lower than the first density of the component32. The third density may be the same as or different to the second density of the granular material34. The casing35may be vacuum sealed to the component32, forming a tight cover around the component32. Alternatively, the casing35may be loosely secured around the component32. The casing35forms a barrier between the component32and the granular material34such that the component32is prevented from contacting the granular material34. The casing35may be transparent or opaque, with the transparent casing enabling the component32to be visible when it is covered by the casing35.

In use, the second example support bed40functions in a similar manner to the first example. The component32is placed into the support bed40and manipulated within the granular material34until the component32is in a desired scanning orientation for scanning by X-ray CT. The component32is completely embedded within the granular material34, in that the component32is completely surrounded by the granular material34. In other examples, the component32may only be partially embedded in the granular material34, in that a part of the component32is not surrounded by the granular material34. The granular material34is able to support the component32in the scanning orientation. An X-ray image of the component32is then captured whilst the component32is in the scanning orientation. As the second density of the granular material34and the third density of the casing35is lower than the first density of the component32, the granular material34and the casing35attenuates X-rays to a lower extent than the component32. This means that the component32can be readily distinguished from the granular material34and the casing35in the X-ray image. The component32can be repositioned within the granular material34such that the component32is in a different scanning orientation. As the granular material34can be readily manipulated, the component32can be moved to the different scanning orientation quickly, and the granular material34can support and retain the component32in the different scanning orientation.

FIG.4shows a third example of a support bed according to the present disclosure. The third example is substantially similar to the second example, with like reference numerals denoting like features. The third example differs from the second example only with respect to the presence of an additional support element.

The support bed50comprises a rigid support element53disposed in the container36. The support element53is formed as a mesh frame which rests on the base of the container36. The support element53is formed from a rigid material. The support element53has a fourth material density which is lower than the first density of the component32. The fourth density may the same as or different to the second density of the granular material34or the third density of the casing35. The support element53is configured to provide additional support for the component32in the container36and retain the component32at a particular location within the container36. In this example, the support element53enables the component32to be in a raised position above the base of the container36. In other examples, the support element may extend from other walls of the container36; for example, a ledge may extend from a side wall of the container36. In further examples, a plurality of support elements may be provided. The support element may also comprise one or more retaining features (e.g., clips or clamps) which help to retain the component32in a particular location in the container36.

In use, the third example support bed50functions in a similar manner to the second example. In addition, the rigid support element53provides a base on which the component32can be placed while it is manipulated within the granular material34to the desired scanning orientation. An X-ray image of the component32is then captured whilst the component32is in the scanning orientation. As the second density of the granular material34, the third density of the casing35, and the fourth density of the support element53is lower than the first density of the component32, the granular material34, the casing35, and the support element53attenuate X-rays to a lower extent than the component32. This means that the component32can be readily distinguished from the granular material34, the casing35, and the support element53in the X-ray image. The component32can be repositioned within the granular material34such that the component32is in a different scanning orientation. As the granular material34can be readily manipulated, the component32can be moved to the different scanning orientation quickly, and the granular material34and the support element53can support and retain the component32in the different scanning orientation.

In other examples, the support bed may have a rigid support element, but there may not be a casing covering the component. The component may then directly contact the granular material and the rigid support element in the support bed.

FIG.5shows a fourth example of a support bed according to the present disclosure. The fourth example support bed comprises similar features to the first example and the second example, with like reference numerals denoting like features.

The support bed60comprises a granular material34disposed in a container66. The container66comprises a housing67having rigid base and side walls. The housing67also comprises a top wall65which is a flexible wall. The top wall65is attached to the side walls of the housing67. The housing67therefore encloses the granular material34. The flexible wall65covers the granular material34and is configured to be manipulated, such that the flexible wall65can be pushed into the granular material34and cause the granular material34to move within the container66. The flexible wall65may be configured to be manipulated against the granular material because the flexible wall65is not attached in a taut manner to the side walls, which provides sufficient slack in the flexible wall65to enable it to be manipulated. Additionally, or alternatively, the housing67may not be completely filled by the granular material34, which provides space for the flexible wall65to be manipulated against the granular material34.

The component32does not have a casing covering the component32. Instead, the flexible wall65forms the barrier between the component32and the granular material34, in that the flexible wall65prevents the component32from contacting the granular material34. The flexible wall65may be formed from a material which has a third density lower than the first density of the component32. In some examples, the granular material34and the flexible wall65may be transparent, which allows the component32to be visible when the component32is embedded in the granular material.

In use, the component32is manipulated against the flexible wall65, which causes the granular material34to move, such that the component32is in a desired scanning orientation and is partially embedded in the granular material34. By being partially embedded, the component32is at least partially surrounded by the granular material34. The granular material34is therefore able to support the component32such that it remains in its scanning orientation. An X-ray image of the component32is then captured whilst the component32is in the scanning orientation. As the second density of the granular material34and the third density of the flexible wall65is lower than the first density of the component32, the granular material34and the flexible wall65attenuate X-rays to a lower extent than the component32. This means that the component32can be readily distinguished from the granular material34and the flexible wall65in the X-ray image. The component32can be repositioned against the flexible wall65such that the component32is in a different scanning orientation. As the flexible wall65and the granular material34can be readily manipulated, the component32can be moved to the different scanning orientation quickly, and the granular material34can support and retain the component32in the different scanning orientation.

FIG.6shows a fifth example of a support bed according to the present disclosure. The fifth example support bed is similar to the fourth example support bed, with like reference numerals denoting like features. The fifth example support bed further comprises a second container.

The fifth example support bed70comprises a first container66and a second container62. The first container66is substantially similar to the container66shown in the fourth example support bed60. The second container62is substantially similar to the first container66. and comprises a granular material64disposed within the container62. The second container62comprises a housing63having rigid top and side walls. The housing63also comprises a bottom wall69which is a flexible wall, which is arranged in a substantially similar manner to the flexible wall65of the first container66. The flexible wall65,69of each of the first and second containers66,62is configured to be manipulated against the granular material34,68and cause the granular material34,68to move within the respective container66,62.

The second container62can be considered to be a copy of the first container66which is turned upside-down and placed on top of the first container66, such that the side walls of the first container66abut against the side walls of the second container62. Thus, in use, the component32is manipulated against the flexible wall65of the first container66, which causes the granular material34in the first container66to move, such that the component32is in a desired scanning orientation and is partially embedded in the granular material34. The second container62is then placed over the component32and the first container66such that the side walls of the first container66abut against the side walls of the second container62. The flexible wall69of the second container62will lie against the outer surface of the component, due to the weight of the granular material68within the second container62. The component32is partially surrounded by the granular material68in the second container62. The component32is completely surrounded by and embedded within the granular material34,68of the first and second containers66,62together. The second container62provides additional support for retaining the component32in the scanning orientation. An X-ray image of the component32is then captured whilst the component32is in the scanning orientation. As the density of the granular material34,68and the density of the flexible walls65,69is lower than the first density of the component32, the granular material64,68and the flexible walls65,69attenuate X-rays to a lower extent than the component32. This means that the component32can be readily distinguished from the granular material64,68and the flexible walls65,69in the X-ray image. The component32can be repositioned with respect to the first and second containers66,62such that the component32is in a different scanning orientation. As the flexible walls65,69and the granular material64,68can be readily manipulated, the component32can be moved to the different scanning orientation quickly, and the granular material64,68can support and retain the component32in the different scanning orientation.

In other examples, the support bed70may comprise more than two such containers which can be arranged together to support the component.

FIG.7shows a sixth example of a support bed according to the present disclosure. The sixth example support bed comprises similar features to the first, second, third, fourth, and fifth examples, with like reference numerals denoting like features.

The sixth example support bed80comprises a first container82and a second container86. The first container82comprises a granular material84encased by a flexible housing85. The second container66also comprises a granular material88encased by a flexible housing89. The flexible housing85,89of each of the first and second containers82,86surrounds the respective granular material84,88to form a sealed bag around the granular material84,88, for example in the manner of a bean bag. The flexible housing85,89may be formed from any flexible material that is readily pliable into different shapes, for example a fabric or polymer-based material. The flexible housing85,89is therefore configured to be manipulated, such that the flexible housing85,89can be pushed against the respective granular material84,88and cause the granular material84,88to move within the respective container82,86. The flexible housing85,89of the first and second containers82,86therefore forms a barrier between the respective granular material84,88and the component32, preventing the granular material84,88from contacting the component32. The flexible housing85,89may be formed from any material which has a lower density than the first density of the component32. In some examples, the granular material84,88and the flexible housing85,89may be transparent, which allows the component32to be visible when the component32is embedded in the granular material84,88.

The granular material84,86of the first and second containers82,86may be in a powdered form. The granular material84,86of the first and second containers82,86may be the same or may be different; however, they both have an overall density which is lower than the first material density of the component32. The granular material84,86of the first and second containers82,86may therefore be any material that has a lower density than the density of the component32.

In use, the first container82is placed on a surface90. The surface90may be substantially flat. The component32is then manipulated and positioned against the flexible housing85of the first container82, causing the granular material84to move within the first container82. The component32is positioned such that it is in a desired scanning orientation and is partially embedded in the granular material84. By being partially embedded, the component32is at least partially surrounded by the granular material84. The granular material84in the first container82is therefore able to support the component32such that it remains in its scanning orientation. The second container86is then placed over the component32and the first container82. The second container86is manipulated with respect to the component32such that the flexible housing89of the second container86lies against the outer surface of the component32. The component32is therefore positioned between the first container82and the second container86. The component32is partially surrounded by the granular material88in the second container86. The component32is completely surrounded by and embedded within the granular material84,88of the first and second containers82,86together. The second container86provides additional support for retaining the component32in the scanning orientation. An X-ray image of the component32is then captured whilst the component32is in the scanning orientation. As the density of the granular material84,88and the density of the flexible housings85,89is lower than the first density of the component32, the granular material84,88and the flexible housings85,89attenuate X-rays to a lower extent than the component32. This means that the component32can be readily distinguished from the granular material84,88and the flexible housings85,89in the X-ray image. The component32can be repositioned with respect to the first and second containers82,86such that the component32is in a different scanning orientation. As the flexible housings85,89and the granular material84,88can be readily manipulated, the component32can be moved to the different scanning orientation quickly, and the granular material84,88can support and retain the component32in the different scanning orientation.

In other examples, the support bed80may only comprise a single container with a flexible housing similar to the first and second containers described above. In further examples, the support bed80may comprise more than two such containers which can be arranged together to support the component therebetween.

FIG.8is a flow diagram showing a method100of scanning a component by computed tomography according to the present disclosure. In a first step102, the method comprises providing the component having a first density. In a second step104, the method comprises supporting the component in a scanning orientation using a support bed. The support bed comprises a granular material disposed in a container, the granular material having a second density lower than the first density. Supporting the component comprises at least partially embedding the component in the granular material. The component is separated from the granular material by a barrier disposed between the component and the granular material. In a third step106, the method comprises scanning the component in the scanning orientation by X-ray or gamma ray scanning to produce an image of the component.

The method of the present disclosure provides an improved method of scanning a component by CT scanning by improving the way in which the component is supported and held in a desired orientation whilst it is scanned. The support bed comprising a granular material disposed in a container provides a fixture for the component which is completely reconfigurable and can support the component in infinitely variable orientations, without requiring a new fixture to be produced for each desired scanning orientation. A single support bed can be used for a multitude of different components and geometries as the granular material can quickly adapt to the different geometries. The support bed is therefore reusable, reducing material waste. The component can be moved between different orientations in a matter of seconds by manipulating it with respect to the granular material. As the density of the granular material is lower than the density of the component, the component can be readily distinguished in the scanned images and the component can be easily inspected. The barrier between the component and the granular material prevents the granular material from contacting the component and prevents the granular material from entering any cavities or crevices of a complex component, which might otherwise reduce the clarity of the image. By providing a flexible wall for the container which acts as the barrier, the component itself does not need to be covered, and the flexible wall and the granular material can robustly support the component, whilst preventing contact between the component and the granular material.

Although it has been described in the above examples that the component is scanned in the scanning orientation by X-rays to produce an image, it will be appreciated that in other examples gamma rays can be used to scan the component and produce an image.