# US 2021/0239585 A1 · System and method for inspecting secondary bonds in laminated parts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239585 A1 - Document ID: US20210239585A1 - Status: Published application - Kind: A1 - Application number: 16/778,714 - Filed: 2020-01-31 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: The Boeing Company - Applicants: The Boeing Company - Inventors: Marcus C. Hart - Web page: https://patentgrep.com/patent/US20210239585A1 ## CPC - G01N 3/24: by applying steady shearing forces (G01N3/26, G01N3/28 take precedence) - G01N 19/04: Measuring adhesive force between materials, e.g. of sealing tape, of coating - G01B 9/08: Optical projection comparators - G01B 11/165: {by means of a grating deformed by the object} - G01N 3/068: {with optical indicating or recording means} - G01N 2203/0234: Low pressure; Vacuum - G01N 2203/0296: Welds - G01N 2203/0647: Image analysis - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract Disclosed herein is a method of inspecting a secondary bond of a laminated part. The method comprises positioning the laminated part within a sealed chamber. The method also comprises reducing a pressure within the sealed chamber to below a pressure outside the sealed chamber when the laminated part is positioned within the sealed chamber. The method further comprises, when the pressure within the sealed chamber is reduced to below the pressure outside the sealed chamber, measuring a gradient of change of a surface profile of the laminated part. The method additionally comprises determining a condition of the secondary bond based on the gradient of change of the surface profile of the laminated part. ## Claims ### Claim 1 A method of inspecting a secondary bond of a laminated part, the method comprising: positioning the laminated part within a sealed chamber; when the laminated part is positioned within the sealed chamber, reducing a pressure within the sealed chamber to below a pressure outside the sealed chamber; when the pressure within the sealed chamber is reduced to below the pressure outside the sealed chamber, measuring a gradient of change of a surface profile of the laminated part; and determining a condition of the secondary bond based on the gradient of change of the surface profile of the laminated part. ### Claim 2 (depends on 1) The method according to claim 1, wherein the gradient of change of the surface profile of the laminated part is measured using a laser shearography process. ### Claim 3 (depends on 1) The method according to claim 1, wherein: the laminated part comprises an internal pocket; the step of determining the condition of the secondary bond comprises determining the condition of the secondary bond as good when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location corresponding with a size, shape, and location of the internal pocket; and the step of determining the condition of the secondary bond comprises determining the condition of the secondary bond as bad when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location that does not correspond with the size, shape, and location of the internal pocket. ### Claim 4 (depends on 3) The method according to claim 3, wherein the step of determining the condition of the secondary bond as bad when the gradient of change of the surface profile of the laminated part indicates the bulge in the laminated part has a size that is bigger than the size of the internal pocket. ### Claim 5 (depends on 3) The method according to claim 3, wherein: the laminated part further comprises a plurality of internal pockets spaced apart from each other; and the size, shape, and location of the bulge in the laminated part does not correspond with the size, shape, and location of the internal pocket when the bulge traverses at least two of the plurality of internal pockets. ### Claim 6 (depends on 3) The method according to claim 3, wherein: the laminated part further comprises a plurality of internal pockets spaced apart from each other; the gradient of change of the surface profile of the laminated part indicates a plurality of bulges in the laminated part; the condition of the secondary bond is determined as good when the size, shape, and location of each one of the plurality of bulges corresponds with the size, shape, and location of a corresponding one of the plurality of internal pockets; and the condition of the secondary bond is determined as bad when the size, shape, and location of any one of the plurality of bulges does not correspond with the size, shape, and location of the corresponding one of the plurality of internal pockets. ### Claim 7 (depends on 1) The method according to claim 1, wherein: the laminated part comprises an internal pocket having a predetermined configuration; and the step of determining the condition of the secondary bond comprises comparing the gradient of change of the surface profile of the laminated part with the predetermined configuration of the internal pocket. ### Claim 8 (depends on 1) The method according to claim 1, wherein: the laminated part further comprises a plurality of internal pockets arranged in a predetermined pattern; and the step of determining the condition of the secondary bond comprises comparing the gradient of change of the surface profile of the laminated part with the predetermined pattern of the plurality of internal pockets. ### Claim 9 (depends on 1) The method according to claim 1, wherein: the laminated part comprises an internal pocket having a predetermined configuration; the step of measuring the gradient of change of the surface profile of the laminated part comprises creating a first digital image of the gradient of change of the surface profile of the laminated part; and the step of determining the condition of the secondary bond comprises automatedly comparing the first digital image of the gradient of change of the surface profile of the laminated part with a second digital image comprising a representation of the internal pocket having the predetermined configuration. ### Claim 10 (depends on 1) The method according to claim 1, wherein the laminated part comprises: a first layer; an intermediate layer adjacent the first layer; and at least a portion of an adhesive between the intermediate layer and the first layer that bonds the intermediate layer to the first layer and forms the secondary bond between the intermediate layer and the first layer. ### Claim 11 (depends on 10) The method according to claim 10, wherein the first layer comprises a plurality of sub-layers. ### Claim 12 (depends on 10) The method according to claim 10, wherein: the intermediate layer comprises an opening; the laminated part further comprises an internal pocket defined by the opening and the first layer; the step of determining the condition of the secondary bond comprises determining the condition of the secondary bond as good when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location corresponding with a size, shape, and location of the internal pocket; and the step of determining the condition of the secondary bond comprises determining the condition of the secondary bond as bad when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location that does not correspond with the size, shape, and location of the internal pocket. ### Claim 13 (depends on 1) The method according to claim 1, wherein the laminated part comprises: a first layer; a second layer; an intermediate layer interposed between the first layer and the second layer; and an adhesive between the intermediate layer and the first layer, the adhesive bonding the intermediate layer to the first layer and forming a first secondary bond between the intermediate layer and the first layer, and between the intermediate layer and the second layer, the adhesive bonding the intermediate layer to the second layer and forming a second secondary bond between the intermediate layer and the first layer; wherein the secondary bond of the laminated part, the condition of which is determined based on the gradient of change of the surface profile of the laminated part, is any one of the first secondary bond or the second secondary bond. ### Claim 14 (depends on 13) The method according to claim 13, wherein: the intermediate layer comprises an opening that extends entirely through a thickness of the intermediate layer; the laminated part further comprises an internal pocket defined by the opening, the first layer, and the second layer; the step of determining the condition of the secondary bond comprises determining the condition of the secondary bond as good when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location corresponding with a size, shape, and location of the internal pocket; and the step of determining the condition of the secondary bond comprises determining the condition of the secondary bond as bad when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location that does not correspond with the size, shape, and location of the internal pocket. ### Claim 15 (depends on 14) The method according to claim 14, wherein each of the first layer, the second layer, and the intermediate layer comprises one or more layers of fiber-reinforced polymeric material. ### Claim 16 A system for inspecting a secondary bond of a laminated part, the system comprising: a sealed chamber, configured to contain the laminated part in a sealed environment; a vacuum device, configured to reduce pressure within the sealed chamber to below a pressure outside the sealed chamber; a shearography apparatus, configured to measure a gradient of change of a surface profile of the laminated part; and a comparison module, configured to determine a condition of the secondary bond based on the gradient of change of the surface profile of the laminated part. ### Claim 17 (depends on 16) The system according to claim 16, wherein the laminated part comprises an internal pocket and the comparison module is configured to: analyze the gradient of change of the surface profile of the laminated part measured by the shearography apparatus; determine the condition of the secondary bond as good when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location corresponding with a size, shape, and location of the internal pocket; and determine the condition of the secondary bond as bad when the gradient of change of the surface profile of the laminated part indicates a bulge in the laminated part having a size, shape, and location that does not correspond with the size, shape, and location of the internal pocket. ### Claim 18 (depends on 17) The system according to claim 17, wherein: the internal pocket has a predetermined configuration; the shearography apparatus is configured to create a first digital image of the gradient of change of the surface profile of the laminated part; and the comparison module is configured to: automatedly compare the first digital image of the gradient of change of the surface profile of the laminated part with a second digital image comprising a representation of the internal pocket having the predetermined configuration; and determine the condition of the secondary bond based on the comparison of the first digital image with the second digital image. ### Claim 19 (depends on 16) The system according to claim 16, wherein: the laminated part further comprises a plurality of internal pockets spaced apart from each other according to a predetermined pattern; the shearography apparatus is configured to create a first digital image of the gradient of change of the surface profile of the laminated part; and the comparison module is configured to: automatedly compare the first digital image of the gradient of change of the surface profile of the laminated part with a second digital image comprising a representation of the plurality of internal pockets arranged in the predetermined pattern; and determine the condition of the secondary bond based on the comparison of the first digital image with the second digital image. ### Claim 20 (depends on 16) The system according to claim 16, wherein the laminated part further comprises a plurality of internal pockets and the comparison module is configured to: analyze the gradient of change of the surface profile of the laminated part measured by the shearography apparatus, wherein the gradient of change of the surface profile of the laminated part indicates a plurality of bulges in the laminated part; determine the condition of the secondary bond as good when a size, shape, and location of each one of the plurality of bulges corresponds with a size, shape, and location of a corresponding one of the internal pocket; and determine the condition of the secondary bond as bad when the size, shape, and location of any one of the plurality of bulges does not correspond with the size, shape, and location of the corresponding one of the plurality of internal pockets.