US-12623425-B2 - Method and apparatus for making a gap filler having a variable cross-section

Abstract

A forming die has a continuously configurable nip allowing a composite preform to be formed into continuous composite gap filler that has a variable cross-section along its length.

Inventors

• Christian Gordon

Assignees

• THE BOEING COMPANY

Dates

Publication Date

20260512

Application Date

20231130

Claims (20)

1. 1 . A method of making a composite gap filler having a varying cross-section, comprising: drawing a composite preform through a nip in a die; changing a shape of the nip; and heating the composite preform to a softening temperature before the composite preform is drawn through the die, wherein changing the shape of the nip includes: synchronously rotating a plurality of die members such that they remain in contact along their edges, wherein each of the plurality of die members is eccentrically mounted for rotation about an axis and having a die face defining a section of the nip.
2. 2 . The method of claim 1 , wherein changing the shape of the nip is performed in real-time while drawing the composite preform through the nip.
3. 3 . The method of claim 1 , wherein: each of the plurality of die members is oval shaped, and changing the shape of the nip includes changing the faces of the die members.
4. 4 . The method of claim 3 , wherein changing the faces of the die members includes at least partially rotating the die members.
5. 5 . The method of claim 4 , wherein changing the faces of the die members further includes tilting the die members.
6. 6 . The method of claim 1 , further comprising: sensing a speed at which the composite preform is drawn through the nip; and synchronizing the speed with changing the shape of the nip.
7. 7 . The method of claim 1 , further comprising: storing electronic data representing a model of a composite gap filler; and automatically changing a shape of the nip based on the electronic data.
8. 8 . The method of claim 1 , wherein changing the shape of the nip is performed as the composite preform is drawn through the nip.
9. 9 . A method of making a composite gap filler having a cross-section that varies along its length (L), comprising: heating a composite preform to a softening temperature sufficient to allow the composite preform to be shaped; drawing the composite preform through a die configured to form the composite preform into a composite gap filler having a desired cross-section; changing the cross-section of the composite gap filler as the composite preform is drawn through the die by altering the die, wherein changing the cross-section of the composite gap filler includes: synchronously rotating a plurality of die members such that they remain in contact along their edges, each of the plurality of die members eccentrically mounted for rotation about an axis and having a die face defining a section of the cross-section of the composite gap filler.
10. 10 . The method of claim 9 , wherein altering the die includes changing a shape of a nip in the die as the composite preform is drawn through the die.
11. 11 . The method of claim 9 , wherein changing the cross-section of the composite gap filler is performed automatically under computer control using a set of electronic data defining the cross-section of the composite gap filler.
12. 12 . The method of claim 9 , further comprising: sensing a speed at which the composite preform is drawn through the die, and wherein altering a shape of the die is synchronized with the speed at which the composite preform is drawn through the die.
13. 13 . The method of claim 9 , wherein each of the plurality of die members is oval shaped with die faces forming a section of the composite gap filler.
14. 14 . The method of claim 9 , wherein altering the die includes changing a shape of a nip of the die in real-time as the preform is drawn through the die.
15. 15 . Apparatus for making a continuous, composite gap filler formed of a composite material and having a cross-section that varies along its length (L), comprising: a die having a nip through which a composite preform may be drawn, the die including a plurality of die members eccentrically mounted for rotation about an axis and configured to form the composite preform into a desired cross-sectional shape, each of the plurality of die members having a changeable die face configured to vary the cross-section of the composite gap filler as the plurality of dies members are synchronously rotated such that they remain in contact along their edges and the composite preform is drawn through the nip; and a heater configured to heat the composite preform to a forming temperature.
16. 16 . The apparatus of claim 15 , wherein: each of the plurality of die members is oval shaped.
17. 17 . The apparatus of claim 16 , further comprising: a die controller configured to control rotation of each of the die members.
18. 18 . The apparatus of claim 17 , further comprising: a speed sensor for sensing a speed (S) at which the composite preform is drawn through the die; and a controller coupled with the speed sensor and the die controller, and configured to synchronize the speed(S) with operation of the die controller.
19. 19 . The apparatus of claim 15 , further comprising: at least one memory; electronic data stored in the memory representing a model of the composite gap filler; and a controller coupled with the memory and configured to control the nip based on the model of the composite gap filler.
20. 20 . The apparatus of claim 15 , wherein the plurality of die members contact each other and form all sides of the nip.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Patent Application No. 63/591,530 filed Oct. 19, 2023, which is incorporated by reference herein. BACKGROUND INFORMATION 1. Field The disclosed embodiments generally relate to production of composite laminate structures, and deal more particularly with a method and apparatus for making a composite gap filler having a variable cross-section along its length. 2. Background Composite laminate structures sometimes have internal voids or gaps that must be filled with material in order to reinforce joints and meet structural performance requirements. For example, composite laminate stiffeners such as stringers may comprise multiple parts joined together in a manner that create gaps along radius corners of the parts. Similar gaps may be present between the stiffener and a structure to which is attached. A continuous gap filler (colloquially referred to as “noodle”) is placed in the gaps and becomes integrated into the stiffener when it is cured. The gap fillers can be formed from any of various composite materials such as pre-preg or dry fiber, and should have cross-sectional shapes and dimensions closely matching those of the gaps. A problem exists in some applications where the cross-section of the gap is not constant along its length, but rather varies in different sections. In order to fill a gap with changing geometry, a filler having a generic geometry is used that best fits most sections of the gap along its length, leaving other sections either under filled or over filled. It may be possible to partially address this problem by using different dies to extrude different sections the filler, but this solution is time-consuming, labor-intensive and requires that the filler be extruded in separate sections, resulting in a gap filler that is not homogeneous. Accordingly, it would be desirable to provide a method and apparatus for producing a continuous, homogeneous, composite gap filler having a cross-section that varies along its length, matching the shape of all sections of the gap. SUMMARY The disclosure relates in general to composite structures having parts forming gaps or voids that must be filled to provide a desired level of structural integrity. More specifically, this disclosure provides a method and apparatus for making a homogeneous, composite gap filler having a variable cross-section that closely matches a gap having changing geometry along its length. One of the advantages of the disclosed method and apparatus is that a composite gap filler with a variable cross-section can be produced that is continuous and homogeneous along its length, rather than in sections. Another advantage is that greater structural integrity can be achieved by a composite gap filler that is continuous throughout all sections of the gap. A further advantage is that a composite gap filler with a varying cross-section can be produced quickly and easily without the need for changing multiple dies, thereby reducing labor costs and increasing production throughput. Still another advantage is that the dimensions of a composite gap filler with a variable cross-section can be more closely controlled. According to one aspect, a method is provided of making a composite gap filler having a varying cross-section. The method comprises drawing a composite preform through a nip in the die, and changing the shape of the nip. According to still another aspect, a method is provided of making a composite gap filler having a cross-section that varies along its length. The method comprises heating a composite preform to a softening temperature sufficient to allow the composite preform to be reshaped, and drawing the composite preform through a die configured to form the composite preform into a composite gap filler having a desired cross-section. The method also includes changing the cross-section of the composite gap filler as a composite preform is drawn through the die by altering the die. According to still another aspect, apparatus is provided for making a continuous, composite gap filler formed of a composite material and having a cross-section that varies along its length. The apparatus comprises a die having a nip through which a composite preform may be drawn. The die includes die members that are configured to form the composite preform into a desired cross-sectional shape. Each of the die members has a changeable die face configured to vary the cross-section of the composite gap filler as the composite preform is drawn through the nip. The features, functions, and advantages can be achieved independently in various examples of the present disclosure or may be combined in yet other examples in which further details can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS The novel features believed characteristic of the illustrative examples are set forth in the appended claims. The illustrativ