NON-DESTRUCTIVE TESTING

Abstract

A method of manufacturing a test component and a method of testing a test component for non-destructive testing (NDT) together with a method of validating an NDT process for a component manufactured by an additive manufacturing (AM) process are disclosed. The validation method includes the steps of forming a first test specimen by the AM process, the test specimen containing one or more defects of a specified type and size, confirming both by destructive testing and by a first NDT step the type and size of the defects, forming the component by the said AM process with an aperture to receive the test specimen, forming a second test specimen by the same AM process which contains defects of the same type and size, inserting into the aperture the second test specimen, arranging the performance of a second NDT step on the component for defects, and comparing the results of the first and second NDT steps to validate the method.

Claims

1. A method of manufacturing a test component for NDT including the steps of forming the component with an aperture shaped to receive a test specimen formed with least one defect and inserting a said test specimen into the said aperture.

2. A method according to claim 1, in which the test specimen and component are formed by an AM process.

3. A method according to claim 1, in which the aperture is formed in the component whereby the at least one defect in the test specimen, when inserted, will be positioned within the component at a location likely to be subject to defects of said component, in production manufacturing.

4. A method according to claim 3, in which a series of test specimens are inserted into respective apertures in the component at locations likely to be subject to defects.

5. A method according to claim 1, in which the test specimen is inserted into the aperture as an interference fit.

6. A method according to claim 1, in which one of the test specimen- and the component is formed with a relief whereby to allow escape of gas as the test specimen is inserted into the component.

7. A method according to claim 1, in which the test specimen is formed as a generally cylindrical plug.

8. A method according to claim 1, in which the test specimen is formed with at least one defect selected from the group: crack, distributed porosity, single pore, inclusion and lack of fusion.

9. A method of validating an NDT process for a component manufactured by an AM process, the method including the steps of, forming by an AM process a first test specimen containing at least one defect of a specified type and size, measuring by a first NDT step the type and size of the at least one defect in the first test specimen, manufacturing a test component for NDT according to the method of claim 1, said test component having a second said test specimen inserted therein, said second test specimen containing at least one defect of the same type and size as that of the first test specimen, arranging the performance of a second NDT step on the test component for defects, and comparing the results of the first and second NDT steps to validate the method.

10. A method according to claim 9, in which at least one of the first and second NDT steps comprises CT scanning.

11. A method according to claim 9, in which the first NDT step includes micro CT scanning.

12. A method according to claim 9, in which the first test specimen is additionally destructively tested to measure the type and size of the at least one defect.

13. A method according to claim 9, in which an NDT step is performed on the second test specimen before insertion into the component.

14. A method of testing a test component manufactured according to the method of claim 1, the method including the performance of an NDT step on the test component for defects in the test specimen.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will now be described, by way of example only, with reference to the following drawings in which:

[0021] FIG. 1 is an isometric view from below of a failsafe bracket for an aircraft, defining a circular aperture to receive a test specimen, for use according to the process of the invention;

[0022] FIG. 2 is an isometric view of a cylindrical test specimen for use according to the process of the invention in the failsafe bracket of FIG. 1 and drawn to a larger scale;

[0023] FIG. 3 is a top plan view of the test specimen of FIG. 2;

[0024] FIG. 4 is a side sectional view of the test specimen of FIG. 2, Cylinder 1, taken along the line C-C and showing a first range of spherical defects;

[0025] FIG. 5 is the same sectional view as FIG. 4 of a second test specimen, Cylinder 2, showing a second range of spherical defects, and

[0026] FIG. 6 is the same sectional view as FIG. 4 of a third test specimen, Cylinder 3, showing a range of linear defects.

DETAILED DESCRIPTION OF THE INVENTION

[0027] As an example of where the method of the invention may be used, a manufacturer may be a supplier of components to a manufacturer of assemblies containing those components, for example an aircraft manufacturer. In order for the assembly manufacturer to confirm the failsafe component quality during production by the component supplier, the assembly manufacturer will have to depend on the NDT techniques used by the component supplier. Such techniques need to be validated to qualify the supplier's NDT facility against the relevant acceptance criteria for the component.

[0028] For example, one acceptance criterion may be that the supplier is able reliably to detect a defect within the component such as gas porosity/less dense inclusions down to 500 m or less and solid inclusions/lack of fusion down to 150 m diameter or less.

[0029] Thus, AM of a test specimen formed with voids or inclusions of a known size and shape, insertion of that test specimen into an actual component and the requirement for the supplier to itself test the component for defects, can be used to ascertain whether the supplier's test methods are able reliably to detect such a defect. The precise size and shape of the known defects can be checked by the assembly manufacturer by high resolution micro CT testing and/or destructive testing.

[0030] Well known destructive testing methods, such as micrographic inspection after dissection of the test specimen, may be carried out by the assembly manufacturer. Following the destructive testing, a further test specimen would be manufactured by AM to a specification identical to that of the test specimen destructively tested. That further test specimen would then be inspected by high resolution CT scanning and inserted into the test component for testing by the supplier or NDT service provider. Comparison of the supplier's test results and the assembly manufacturer's test results would then enable validation of the supplier's test methods and their NDT capabilities.

[0031] With reference to FIG. 1, a failsafe bracket 1 for structural analysis is manufactured by an AM electron beam powder bed process out of Ti6A14V material. The component 1 has a cylindrical aperture 2 formed through a lower surface 3 thereof. The aperture 2 is formed as the component 1 is being manufactured but could be drilled instead. Referring to FIG. 2, a cylindrical test specimen 4 is formed of the same material by the same AM process and is shaped to be inserted as an interference fit into the aperture 2, in the direction of the arrow. Alternatively, a close sliding fit may be adequate in certain circumstances. The test specimen 4 may be surface finished by any suitable process if necessary, in order to form a smooth cylindrical surface for insertion into the aperture 2 of the bracket 1. Although only one aperture 2 is shown in FIG. 1, the component may be formed with as many apertures as are required to accommodate test specimens. For example, the manufacturing process may tend to form defects at locations in the region of a thickening of the structure, such as at the location of the aperture 2, shown in FIG. 1. In such a case, apertures may be formed and test specimens inserted at all or a representative sample of such locations in the structure.

[0032] The test specimen 4 has a V-shaped groove 5 formed along its length to act as an air escape channel as the test specimen is pressed into the aperture 2 of the bracket 1.

[0033] The test specimen 4 has been deliberately formed with a variety of defects 6, 7, 8, 9, during the AM process and these defects are discussed below in relation to FIGS. 4, 5 and 6 and cylinders 1, 2 and 3, respectively. All defects are centrally positioned within the test specimen 4.

[0034] Table 1, relating to Cylinder 1 as illustrated in FIG. 4, shows the diameter of four spherical defects intentionally formed during the AM manufacturing process of the test specimen 4.

[0035] Table 2, relating to Cylinder 2 as illustrated in FIG. 5, shows the diameter of four further spherical defects intentionally formed during the AM manufacturing process of the test specimen 4.

[0036] Table 3, relating to Cylinder 3 as illustrated in FIG. 6, shows the dimensions of four linear defects intentionally formed during the AM manufacturing process of the test specimen 4. The linear defects are all 500 m in length but their orientation within the test specimen differs as do their widths and thicknesses.

TABLE-US-00001 TABLE 1 (CYLINDER 1) Defect reference Nominal diameter 1 150 m 2 200 m 3 300 m 4 400 m

TABLE-US-00002 TABLE 2 (CYLINDER 2) Defect reference Nominal diameter 1 500 m 2 600 m 3 800 m 4 1000 m

TABLE-US-00003 TABLE 3 (CYLINDER 3) Defect reference Angle to horizontal Length Width Thickness 1 0 500 m 200 m 200 m 2 45 500 m 200 m 200 m 3 0 500 m 300 m 300 m 4 45 500 m 300 m 300 m

[0037] Depending upon the specific requirements of the component concerned, the test specimens 4, shown in FIGS. 4, 5 and 6, may be inserted into separate apertures in a single component 1 or, in sequence, into a single aperture in a component 1. All the test specimens may not be required, however, if it is determined that not all of the defects listed above are likely to occur in the component concerned. Thus, for example, a single test specimen may contain two spherical defects of differing diameter and two linear defects of differing length. The type and size of defect created in the test specimen and the number of test specimens used will always depend upon a specific need for the supplier or other entity whose NDT capabilities are being tested to identify defects of a specific type and size for a particular component of a given size and geometry.

[0038] The embodiments described herein are respective non-limiting examples of how the present invention, and aspects of the present invention, may be implemented. Any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined by the accompanying claims.

[0039] The word or as used herein is to be taken to mean and/or unless explicitly stated otherwise.