A forming tool and method for composite f-section bars
By using a tooling consisting of an upper split mold, a middle split mold, and a lower split mold, combined with a side pressure plate and a hot autoclave forming method, the problems of internal quality and surface accuracy of parts during the forming process of composite material F-section ribs were solved, and efficient forming operation was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AVIC BEIJING AERONAUTICAL MFG TECH RES INST
- Filing Date
- 2023-06-16
- Publication Date
- 2026-05-19
AI Technical Summary
Existing technologies make it difficult to simultaneously ensure the internal quality and surface accuracy of parts during the forming process of composite material F-section ribs, and the operation is complex and inefficient.
The tooling consists of an upper split mold, a middle split mold, and a lower split mold. Combined with a lateral pressure plate, the tooling achieves precise positioning and efficient forming of F-shaped cross-section ribs of composite materials through vacuuming and autoclave forming.
It achieves accurate positioning of F-section ribs in composite materials, ensuring the internal quality and surface accuracy of parts, while simplifying the operation process and improving molding efficiency.
Smart Images
Figure CN116766627B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aerospace composite material manufacturing technology, specifically to a forming tooling and method for F-section stiffeners of composite materials. Background Technology
[0002] Composite materials, due to their high specific strength, high specific hardness, strong design flexibility, good fatigue fracture resistance, corrosion resistance, good dimensional stability, and ease of large-area integral molding, have become one of the most important structural materials in modern aerospace. To improve the stiffness of composite materials and enhance the overall design integration, "F"-shaped ribs are increasingly being used in the aerospace field. However, molding F-shaped cross-section ribs in composite materials is quite difficult, and controlling both the surface and internal quality is challenging.
[0003] Currently, most aerospace composite material molding processes utilize autoclave molding. In the molding of F-section ribs for composite materials, there are numerous prepreg layup groups, making it difficult to fill the R-zone with prepreg, which easily leads to defects in the R-corner area. If rigid, modular metal tooling is used, it is difficult to accurately position the mold blocks, and the tooling design is generally quite complex.
[0004] How to ensure the internal quality and surface accuracy of parts while simplifying operations and improving molding efficiency remains a challenge.
[0005] Therefore, the inventors provide a forming tooling and method for F-section stiffeners of composite materials. Summary of the Invention
[0006] (1) Technical problems to be solved
[0007] This invention provides a molding fixture and method for F-shaped cross-section ribs of composite materials, solving the technical problem of how to simultaneously improve the internal quality, surface accuracy and molding efficiency of F-shaped cross-section ribs.
[0008] (2) Technical solution
[0009] A first aspect of the present invention provides a forming fixture for F-section stiffeners of composite materials, comprising an upper split mold, a middle split mold, a lower split mold, and a lateral pressure plate; the upper surface of the lower split mold is adapted to the lower surface of the F-section stiffener of the composite material, and the outermost end of the upper surface of the lower split mold is provided with a middle split mold limiting boss; the surface of the middle split mold is adapted to the middle surface of the F-section stiffener of the composite material, and the outermost end of the upper surface of the middle split mold is provided with an upper split mold limiting boss; the lower surface of the upper split mold is adapted to the upper surface of the F-section stiffener of the composite material.
[0010] The lateral pressure plate is located on the side of the upper split mold, the middle split mold and the lower split mold, and its lateral profile is adapted to the lateral profile of the F-shaped cross-section rib of the composite material.
[0011] Furthermore, the height of the center-part mold limiting boss is 20-25mm, and the width is 10-20mm.
[0012] Furthermore, the bottom of the lower split mold is provided with a support base for supporting the lateral pressure plate.
[0013] Furthermore, the height of the center-part mold limiting boss is 20-25mm, and the width is 10-20mm.
[0014] Furthermore, the upper split mold, the middle split mold, and the lower split mold are made of steel.
[0015] Furthermore, the lateral pressure plate is made of composite material.
[0016] Furthermore, the coefficient of thermal expansion of the lateral pressure plate is the same as that of the composite material F-section stiffener.
[0017] Furthermore, the thickness of the lateral pressure plate is 1 to 2 mm.
[0018] A second aspect of the present invention provides a method for forming F-section stiffeners for composite materials, comprising the following steps:
[0019] Prepreg is laid on the lower split mold and the middle split mold respectively;
[0020] Then, the lower split mold and the middle split mold are combined into a tooling assembly. The tooling assembly is vacuumed, and the R-corner area is filled with prepreg unidirectional tape. Then, prepreg is laid on the tooling assembly again.
[0021] Then, the upper split mold and the side pressure plate are installed on the combined tooling, vacuum is applied again, and the parts are sealed and sent into the autoclave for molding.
[0022] Furthermore, after the encapsulation and autoclave molding, the process further includes:
[0023] First, remove the lateral pressure plate, then pull the upper split mold out of the overall tooling, then remove the middle split mold and the composite material F-shaped cross-section ribs from the lower split mold, and finally remove the middle split mold from the composite material F-shaped cross-section ribs to complete the demolding process.
[0024] (3) Beneficial effects
[0025] In summary, this invention uses a tooling assembly consisting of an upper split mold, a middle split mold, and a lower split mold to achieve accurate positioning of F-shaped cross-section ribs in composite materials, ensuring the internal quality and surface accuracy of the parts while being simple to operate and highly efficient. Attached Figure Description
[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is a schematic diagram of a forming tool for F-section stiffeners of composite materials provided in an embodiment of the present invention;
[0028] Figure 2 This is a schematic diagram of the combined structure of the lower split mold, middle split mold, and upper split mold in a tooling for forming F-shaped cross-section ribs of composite materials, provided in an embodiment of the present invention;
[0029] Figure 3 This is a schematic diagram of a structure for a composite material F-section reinforcing bar prepreg layup provided by an embodiment of the present invention;
[0030] Figure 4 This is a schematic flowchart of a method for forming F-shaped cross-section ribs of composite materials according to an embodiment of the present invention.
[0031] In the picture:
[0032] 1-Upper split mold; 2-Middle split mold; 201-Upper split mold limiting boss; 3-Lower split mold; 301-Middle split mold limiting boss; 302-Support base; 4-Side pressure plate; 5-Composite F-section rib; 501-Composite F-section rib middle split mold ply assembly; 502-Composite F-section rib lower split mold ply assembly; 503-Composite F-section rib side ply assembly; 504-Composite F-section rib R-corner filling area. Detailed Implementation
[0033] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.
[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0035] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0036] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0037] Figure 1 This is a schematic diagram of a forming tool for F-section ribs of composite materials provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the molding fixture may include an upper split mold 1, a middle split mold 2, a lower split mold 3, and a side pressure plate 4; the upper surface of the lower split mold 3 is adapted to the lower surface of the composite material F-section rib, and the outermost end of the upper surface of the lower split mold 3 is provided with a middle split mold limiting boss 301; the surface of the middle split mold 2 is adapted to the middle surface of the composite material F-section rib, and the outermost end of the upper surface of the middle split mold 2 is provided with an upper split mold limiting boss 201; the lower surface of the upper split mold 1 is adapted to the upper surface of the composite material F-section rib; the side pressure plate 4 is located on the side of the upper split mold 1, the middle split mold 2, and the lower split mold 3, and its side surface is adapted to the side surface of the composite material F-section rib.
[0038] In the above embodiment, the assembly relationship between the upper split mold 1, the middle split mold 2, and the lower split mold 3 is as follows: Figure 2 As shown, the assembly gaps between the three separate molds are used to fill the prepreg to form the F-section ribs of the composite material. The assembly and positioning of the three separate molds are accurate, ensuring the internal quality and surface precision of the parts, while also being simple and efficient to operate.
[0039] As an optional implementation, the height of the center-part mold limiting boss 201 is 20-25mm, and the width is 10-20mm. The specific dimensions of the center-part mold limiting boss 201 are not limited, but are selected based on the dimensions of the F-shaped cross-section ribs of the composite material to be molded.
[0040] As an optional implementation, the bottom of the lower split mold 3 is provided with a support base 302 for supporting the lateral pressure plate 4. Specifically, as shown... Figure 1 As shown, the support base 302 is mainly used to support and limit the lateral pressure plate 4, thereby enabling the lateral pressure plate 4 to be installed in conjunction with the upper split mold 1, the middle split mold 2, and the lower split mold 3, preventing the prepreg material from falling from the left side during the rib forming process. Figure 1 Deformation occurs in the direction shown, ensuring the forming accuracy of the composite material F-section ribs.
[0041] As an optional implementation, the height of the center-part mold limiting boss 301 is 20-25mm, and the width is 10-20mm. The specific dimensions of the center-part mold limiting boss 301 are not limited, but are selected based on the dimensions of the F-shaped cross-section ribs of the composite material to be molded.
[0042] As an optional implementation, the upper split mold 1, the middle split mold 2, and the lower split mold 3 are made of steel. Specifically, they are manufactured using CNC machining of Q235 steel.
[0043] As an optional implementation, the lateral pressure plate 4 is made of composite material, and the coefficient of thermal expansion of the lateral pressure plate 4 is the same as that of the composite material F-section rib. It should be noted that the material of the lateral pressure plate 4 is selected to enable real-time positioning of the composite material F-section rib, thereby improving molding accuracy.
[0044] As an optional implementation, the thickness of the side pressure plate 4 is 1 to 2 mm. The specific dimensions of the side pressure plate 4 are not limited, but are selected based on the dimensions of the F-shaped cross-section ribs of the composite material to be formed.
[0045] Figure 4 This is a schematic flowchart of a method for forming F-section stiffeners of composite materials according to an embodiment of the present invention, as shown below. Figure 4 As shown, the method may include the following steps:
[0046] S100, prepreg is laid on the lower split mold and the middle split mold respectively;
[0047] S200. Combine the lower split mold and the middle split mold into a combined tooling, vacuum the combined tooling, fill the R-corner area with prepreg unidirectional tape, and then lay prepreg again on the combined tooling.
[0048] S300: Mount the upper split mold and side pressure plate onto the assembly fixture, vacuum again, seal, and send to the autoclave for molding.
[0049] In the above embodiment, before step S100, a release agent needs to be evenly applied to the lower split mold 3, the middle split mold 2, the upper split mold 1 and the side pressure plate 4.
[0050] Among them, the structure of the composite material F-section stiffener prepreg layup is as follows: Figure 3 As shown, composite material F-section rib lower split mold ply assembly 502 is laid on the lower split mold 3, and composite material F-section rib middle split mold ply assembly 501 is laid on the middle split mold 2; then the lower split mold 3 and the middle split mold 2 are assembled into a combined tooling, and a vacuum operation is performed on the combined tooling. After filling the R-corner filling area 504 of the composite material F-section rib with unidirectional prepreg, the tooling is vacuumed; composite material F-section rib lateral ply assembly 503 is laid on the combined tooling.
[0051] As an optional implementation, after encapsulation and molding in a hot autoclave in step S300, the process further includes: S400, first removing the side pressure plate, then pulling the upper split mold out of the overall tooling, then removing the middle split mold and the composite material F-shaped cross-section ribs from the lower split mold, and finally removing the middle split mold from the composite material F-shaped cross-section ribs to complete the demolding process.
[0052] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.
[0053] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.
Claims
1. A forming tool for F-section stiffeners of composite materials, characterized in that, It includes an upper split mold (1), a middle split mold (2), a lower split mold (3), and a side pressure plate (4); the upper surface of the lower split mold (3) is adapted to the lower surface of the composite material F-section rib, and the outermost end of the upper surface of the lower split mold (3) is provided with a middle split mold limiting boss (301); the surface of the middle split mold (2) is adapted to the middle surface of the composite material F-section rib, and the outermost end of the upper surface of the middle split mold (2) is provided with an upper split mold limiting boss (201); the lower surface of the upper split mold (1) is adapted to the upper surface of the composite material F-section rib. The lateral pressure plate (4) is located on the side of the upper split mold (1), the middle split mold (2) and the lower split mold (3), and its lateral profile is adapted to the lateral profile of the F-shaped cross section rib of the composite material; the bottom of the lower split mold (3) is provided with a support base (302) for supporting the lateral pressure plate (4); The upper split mold (1), the middle split mold (2) and the lower split mold (3) are made of steel. The thickness of the side pressure plate (4) is 1-2 mm. The composite material F-shaped cross-section rib forming mode is F vertical placement.
2. The forming tooling for F-section stiffeners of composite materials according to claim 1, characterized in that, The height of the upper split mold limiting boss (201) is 20-25mm and the width is 10-20mm.
3. The forming tooling for F-section stiffeners of composite materials according to claim 1, characterized in that, The height of the central split mold limiting boss (301) is 20-25mm and the width is 10-20mm.
4. The forming tooling for F-section stiffeners of composite materials according to claim 1, characterized in that, The side pressure plate (4) is made of composite material.
5. The forming tooling for F-section stiffeners of composite materials according to claim 4, characterized in that, The thermal expansion coefficient of the lateral pressure plate (4) is the same as that of the composite material F-section stiffener.
6. A forming method using a forming fixture for F-section ribs of composite materials as described in any one of claims 1-5, characterized in that, The method includes the following steps: Prepreg is laid on the lower split mold and the middle split mold respectively; Then, the lower split mold and the middle split mold are combined into a tooling assembly. The tooling assembly is vacuumed, and the R-corner area is filled with prepreg unidirectional tape. Then, prepreg is laid on the tooling assembly again. Then, the upper split mold and the side pressure plate are installed on the combined tooling, vacuum is applied again, and the parts are sealed and sent into the autoclave for molding.
7. The molding method according to claim 6, characterized in that, After the process of encapsulation and deposition in an autoclave, the method further includes: First, remove the lateral pressure plate, then pull the upper split mold out of the overall tooling, then remove the middle split mold and the composite material F-shaped cross-section ribs from the lower split mold, and finally remove the middle split mold from the composite material F-shaped cross-section ribs to complete the demolding process.