Composite laminate thickness compensation

Patent metadata

Field	Value
Publication number	US-9586367-B2
Application number	US-26475708-A
Country	US
Kind code	B2
Filing date	Nov 4, 2008
Priority date	Nov 4, 2008
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A method is provided for the non-contact measurement of variations in thickness of composite materials and structures prepared from composite parts. Metrologic methods are employed to provide a 3D image of the structure or part. Variations that are greater than an acceptable amount can be corrected by adding a compensation layer to the surface of the structure or part.

First claim

That claimed is:

1. A method for identifying and correcting for variations in thickness in a skin or outer panel designed to be attached to a structural member of a structure, defining a composite article, the method comprising the steps of:
(a) applying composite layers to a mold surface of a forming tool and while on the mold surface, heating the composite layers to cure the composite layers, thereby providing the composite article configured for attachment to the structural member of the structure, the composite article having an inner mold-line surface that when installed faces the structure, and an outer-mold-line surface opposite the inner mold-line surface, the outer mold-line surface having a surface shape which approximates the mold surface, and which defines an outermost surface of the skin or outer panel and which is on a side opposite from the structural member;
(b) measuring a profile of portions of the inner mold-line surface of the composite article, and a profile of portions of the mold surface of the forming tool using a coherent laser radar to generate a calculated thickness data set for the composite article, the measured profile of the portions of the mold surface approximating corresponding portions of the profile of the outer mold-line surface of the composite article;
(c) analyzing the calculated thickness data set for the composite article and determining if the thickness of any areas of the composite article are not within a predetermined range to thereby identify one or more excursions of the calculated thickness in the any areas when existing, an excursion of calculated thickness being defined as a thickness variation of a portion of the composite article between a calculated thickness of the portion of the composite article and a nominal thickness that is greater than an acceptable amount;
(d) correcting for an excursion of the calculated thickness in areas on the outer mold line of the composite article that are outside of the predetermined range by:
(i) providing compensation material that has a thickness substantially the same as the respective excursion, and
(ii) applying the compensation material on an outermost surface of the outer mold line and to the respective area of the composite article having the respective excursion.

2. The method of claim 1 , wherein the composite article comprises a first composite article and wherein the excursion comprises a thickness variation between the first composite article and a second composite article that is disposed adjacent the first composite article.

3. The method of claim 1 wherein measuring the profile of portions of the inner mold line surface of the composite article is performed while the composite article is still on the mold surface of the forming tool.

4. The method of claim 1 ,
wherein step (d) comprises correcting for an excursion of the calculated thickness in each of the any areas of the inner mold-line surface of the composite article that are outside of the predetermined range; and
wherein the method further comprises placing portions of the inner mold-line surface of the composite article against the structural member, and securing the composite article to the structural member after the compensation material has been applied.

5. The method of claim 1 wherein the compensation material comprises a plurality compensation layers of known thickness, and wherein the step of correcting for a variation in the calculated thickness further comprises the steps of
calculating the thickness variation;
calculating the shape and location of the plurality of compensation layers necessary to reduce the thickness variation of the composite article to within the predetermined acceptable thickness variation;
supplying a data set relating the calculated shape of the plurality of compensation layers to an automated broadgoods cutter to produce the plurality of compensation layers;
producing the plurality of compensation layers with the automated broadgoods cutter, the plurality of compensation layers collectively having a shape and thickness necessary to reduce the thickness variation of the composite article to within the predetermined acceptable thickness variation; and
applying the plurality of compensation layers to the composite article.

6. The method of claim 5 wherein the step of applying the plurality of compensation layers to the composite article includes the steps of:
supplying a data set relating the shape and location of the plurality of compensation layers to a laser projector to guide in the application of the plurality of compensation layers,
applying the plurality of compensation layers to the composite article using the laser projector, and
curing the plurality of compensation layers on the composite article to bond them permanently in place to thereby reduce the thickness variation of the composite article.

7. The method as defined in claim 1 , wherein the composite article is a first composite article, wherein the any areas that are outside of the predetermined range comprises a area of the first composite article adjacent a area of a second composite article, wherein the substep of correcting for an excursion of the calculated thickness that are outside of the predetermined range compensates for a thickness variation between the area of the first composite article and the area of the second composite article adjacent thereto, performed without machining the compensation material after the compensation material is applied to the respective area of the composite article having the excursion of the calculated thickness.

8. The method as defined in claim 1 ,
wherein the any areas comprises a plurality of areas; and
wherein each of the plurality of areas having the excursion of calculated thickness covers less than an entire portion of the composite article to thereby define a plurality of discrete excursions.

9. The method as defined in claim 8 ,
wherein the excursion results from a recess in the area on a surface of the composite article, the recess having an at least partially concave shape; and
wherein the compensation material comprises a plurality of compensation layers forming a stack of compensation layers, an initial one of the stacked layers having a smaller size than an adjacent stacked layer stacked upon the initial stacked layer.

10. The method as defined in claim 9 , wherein the compensation material comprises a stack of a plurality of compensation layers, and wherein each compensation layer in the stack of compensation layers is sized to match the dimensions of the portion of the recess to which it is being applied.

11. The method as defined in claim 1 ,
wherein the structure comprises a aircraft, the structural member being a component of the aircraft;
wherein the each area of the composite article that are outside of the predetermined range comprises a plurality of areas critical each covering less than an entire portion of the composite article;
wherein each area of the composite article having a thickness within the predetermined range is not bonded with the compensation material; and
wherein the method further comprises attaching the composite article to the component of the aircraft.

12. A method for forming a composite skin or panel for a component of an aircraft, comprising the steps of:
(a) applying composite layers to a mold surface;
(b) curing the composite layers while on the mold surface to create a composite skin or panel with an inner mold-line and an outer-mold-line surface;
(c) scanning the inner mold-line surface of the skin or panel and recording data points representative of a profile of the inner mold-line surface of the skin

Assignees

• Drewett Jeffrey T
• Briney Paul T
• White Grady L
• Kelly Gary L
• Hestness Michael L
• Ashton Todd H
• Morken Peter L
• Lockheed Corp

Inventors

• Drewett Jeffrey T
• Briney Paul T
• White Grady L
• Kelly Gary L
• Hestness Michael L
• Ashton Todd H
• Morken Peter L

Classifications

• B29C73/10

  using patches sealing on the surface of the article (B29C73/14 takes precedence) · CPC title

• B29K2995/0097

  Thickness · CPC title

• B29C70/54 Primary

  Component parts, details or accessories; Auxiliary operations {, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing} · CPC title