METHOD FOR PRODUCING COMPOSITE COMPONENTS HAVING AN UNDEVELOPABLE SURFACE

Abstract

Method for producing composite components having an undevelopable surface. To be able to maintain the tolerances when manufacturing especially large components in the case of composite components with undevelopable surfaces, it is proposed according to the invention to drape a cut-to-size blank on a molding tool and to determine the deviation of the cut-to-size blank edge from the setpoint cut-to-size edge. Then, on the basis of the deviation, a new cut-to-size blank edge is calculated, and a new cut-to-size blank is created and re-draped for examination purposes. The method is repeated until the deviations are below a tolerable threshold value. The method is furthermore carried out for each textile ply of the composite component.

Claims

1. A method for ascertaining cutting-to-size data, on a basis of which a textile sheet material can be cut to size to obtain a cut-to-size textile ply suitable for production of a composite component that is formed from textile plies and has an undevelopable surface, the method comprising: a) providing a textile sheet material in a form of a cut-to-size blank, which has at least one cut-to-size blank edge; b) draping the cut-to-size blank on a molding tool or preceding cut-to-size blank suitable for the production of the composite component; c) ascertaining a deviation of a profile, resulting from step b), of the cut-to-size blank edge and a profile, predefined by the undevelopable surface, from setpoint cut-to-size edges; d) when an extent of the deviation ascertained in step c) is above a predefined threshold value: removing the cut-to-size blank and changing the profile of the cut-to-size blank edge based on the deviation ascertained in step c) and repeating steps b) to d), otherwise storing the profile of the cut-to-size blank edge for this cut-to-size blank in a form of cutting-to-size data, and leaving the cut-to-size blank on the molding tool or the preceding cut-to-size blank.

2. The method of claim 1, wherein in step a) the cut-to-size blank is cut to size from the textile sheet material as in a case of a developable surface.

3. The method of claim 1, wherein in step a) the cut-to-size blank is formed by a textile sheet material that has an oversize in relation to a molding tool suitable for the production of the composite component.

4. The method of claim 1, wherein in step c) the deviation is ascertained using a measuring grid and/or a setpoint cut-to-size edge projected onto the cut-to-size blank.

5. The method of claim 1, wherein in step c) the deviation is ascertained using an image recording or a 3D scan of the cut-to-size blank and a corresponding evaluation.

6. The method of claim 1, wherein in step d) the profile of the cut-to-size blank edge is changed by cutting to size a further cut-to-size blank based on the changed profile of the cut-to-size blank edge.

7. The method of claim 1, wherein in step d) the profile of the cut-to-size blank edge is changed by continuing to cut the cut-to-size blank based on the changed profile of the cut-to-size blank edge.

8. The method of claim 1, wherein steps a) to d) are carried out for each textile ply of the composite component.

9. A method for cutting a textile sheet material to size to obtain a cut-to-size textile ply suitable for production of a composite component that is formed from textile plies and has an undevelopable surface, the method comprising: a) carrying out the method of claim 1 to obtain cutting-to-size data; and b) cutting the textile sheet material to size based on the cutting-to-size data to obtain the cut-to-size textile ply.

10. A method for producing a composite component that is formed from textile plies and has an undevelopable surface, the method comprising: a) carrying out the method of claim 9; b) draping cut-to-size textile plies on the molding tool to obtain a component precursor formed from textile plies; and c) carrying out a transfer molding method with a closed mold or a vacuum method with a vacuum bag to form the composite component from the component precursor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Example embodiments will be explained in more detail with reference to the appended schematic drawings, in which:

[0072] FIG. 1 shows an example of a ramp with different textile plies;

[0073] FIG. 2 shows a perspective view of a cut-to-size blank draped on a molding tool;

[0074] FIG. 3 shows an illustration of a measurement of the deviation of the cut-to-size blank edges from the setpoint cut-to-size edges; and

[0075] FIG. 4 shows an illustration of a change in the profile of the cut-to-size blank edge.

DETAILED DESCRIPTION

[0076] Reference is firstly made to FIG. 1, on the basis of which the problem addressed by the disclosure herein is to be explained in more detail. FIG. 1 shows a two-part molding tool 110. The tool halves 112, 114 enclose a mold cavity 116. A plurality of textile plies 118 of textile sheet material are arranged therein. The component to be formed therefrom is to have a ramp 120 in one region. The textile plies 118 adjoining the ramp 120 are ideally cut such that they follow the profile of the ramp 120 when placed one on top of another (at the top in FIG. 1). This results in a certain fiber volume content (FVC), illustrated in the diagrams, along the horizontal profile of the textile plies 118 (Position). The FVC corresponds to a nominal FVC 122 and is somewhat smaller in the region of the ramp 120. In this situation, the tool halves 112, 114 can be closed and the textile plies 118 can be provided with resin and cured in a manner known per se.

[0077] It is different, for example, if one of the textile plies 118 has an oversized region 124, as illustrated at the bottom in FIG. 1. In this case, in the region of the ramp 120 the FVC increases above the nominal FVC 122, this generally resulting in the molding tool 110 no longer being able to be closed.

[0078] It is also possible that one of the textile plies 118 has a shorter form, with the result that a certain overhang of the textile ply 118 lying above it forms. In this case, the FVC falls in turn below the nominal FVC 122 and can be compensated in another way.

[0079] The aim of the methods described below is in particular to avoid the aforementioned situations to the best possible extent.

[0080] Reference is made below to FIGS. 2 to 4, which schematically show individual stations of a method for producing a composite component 10 with an undevelopable surface. Undevelopable surfaces have a double curvature to an extent that no longer permits conventional manufacture within predefined tolerances.

[0081] The composite component 10 is preferably an aircraft composite component suitable for an aircraft. Examples of such aircraft composite components are the rear pressure bulkhead and the wing tips, in particular with Sharklets. Wing tips are usually considered to be the last 4 to 5 meters of the wing in the outboard direction.

[0082] The composite component 10 is constructed from a plurality of textile plies 12. The textile plies 12 are textile sheet materials and may be prepregs, woven fabrics or laid fabrics, for example.

[0083] First of all, the textile sheet material 14 is cut to size by using a conventional method. In the process, the 2D cut grid for the sheet material 14 can be calculated by CAD software that is conventional in the art. However, in order to stay within predefined tolerances, the following refinement according to the disclosure herein is necessary.

[0084] The sheet material 14 is firstly draped on a molding tool 16 in the form of a cut-to-size blank 18. The cut-to-size blank 18 has at least one cut-to-size blank edge 20. On account of the properties of undevelopable surfaces, the profile of the cut-to-size blank edge 20 will not correspond to the profile of the setpoint cut-to-size edge 22. The setpoint cut-to-size edge 22 specifies where the cut-to-size blank edge 20 should run so that the desired geometry within the tolerance limits is brought about after the cut-to-size blank 18 has been draped.

[0085] Then, as is illustrated in more detail in FIG. 3, the deviation of the cut-to-size blank edge 20 from the setpoint cut-to-size edge 22 is measured. In one case, this can be done by a laser projection of the setpoint cut-to-size edge 22 and a measuring grid 24. The deviations 26 of the cut-to-size blank edge 20 and the setpoint cut-to-size edge 22 can be measured pointwise by hand, for example.

[0086] However, it is preferred that the cut-to-size blank edge 20 is measured automatically, for example using an image evaluation method or on the basis of a laser scan. The methods required for determining edges and distances are well known per se in other fields.

[0087] If the extent of the ascertained deviations 26 is above a predefined threshold value, the profile of the cut-to-size blank edge 20 is changed. The extent of the deviations 26 can be ascertained by gradient methods or similar methods, for example.

[0088] In this way, it is possible to ascertain a correction 28 for each measured point on the cut-to-size blank edge 20 from the deviations 26.

[0089] As is illustrated in more detail in FIG. 4, the cut-to-size blank edge 20 is changed on the basis of the deviations 26 or of the correction 28 calculated from them. The result is a new profile of the cut-to-size blank edge 20.

[0090] Then, a new cut-to-size blank 18 of the new cut-to-size blank edge 20 is created and in turn draped on the molding tool 16 or optionally on a preceding cut-to-size blank 18. Then, in turn, the deviation 26 of the profile of the cut-to-size blank edge 20 from the setpoint cut-to-size edge 22 is ascertained.

[0091] When the extent of the deviations 26 is below the predefined threshold value, the cut-to-size blank 18 remains on the molding tool 16 or a preceding cut-to-size blank 18. The cutting-to-size data, which specify the profile taken by the cut-to-size blank edge 20, are stored for this specific textile ply 12 and can then be used for the further production.

[0092] The method is carried out for each textile ply 12 incorporated in the composite component 10.

[0093] What is produced overall, iteratively and ply-by-ply, is therefore a 2D cut-to-size shape, which can create a composite component 10 within the predefined tolerances when draped on the molding tool 16.

[0094] In mass production, the textile sheet materials 14 are cut to size on the basis of the cutting-to-size data ascertained for each layer of the composite component 10 and then draped on the molding tool 16.

[0095] The molding tool 16 may be part of a closed molding process, such as for instance transfer molding (or resin transfer molding, RTM), but it can also be effected in combination with a vacuum bag method, optionally using pressure pieces.

[0096] In order to be able to maintain the tolerances when manufacturing especially large components in the case of composite components 10 with undevelopable surfaces, it is proposed according to the disclosure herein to drape a cut-to-size blank 18 on a molding tool 16 and to determine the deviation 26 of the cut-to-size blank edge 20 from the setpoint cut-to-size edge 22. Then, on the basis of the deviation 26, a new cut-to-size blank edge 22 is calculated and a new cut-to-size blank 18 is created and re-draped for examination purposes. The method is repeated until the deviations 26 are below a tolerable threshold value. The method is furthermore carried out for each textile ply 12 of the composite component 10.

[0097] While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE SIGNS

[0098] 10 Composite component

[0099] 12 Textile ply

[0100] 14 Sheet material

[0101] 16 Molding tool

[0102] 18 Cut-to-size blank

[0103] 20 Cut-to-size blank edge

[0104] 22 Setpoint cut-to-size edge

[0105] 24 Measuring grid

[0106] 26 Deviation

[0107] 28 Correction

[0108] 110 Molding tool

[0109] 112 Tool half

[0110] 114 Tool half

[0111] 116 Mold cavity

[0112] 118 Textile ply

[0113] 120 Ramp

[0114] 122 Nominal FVC

[0115] 124 Oversized region