A forming tool for a composite material skin with a flange

Abstract

This utility model relates to the field of aerospace technology, and in particular to a molding die for a composite material skin with a flange, comprising an upper die, a lower die, and a drill die; a front insert is installed at the upper end of the lower die, and the upper die is sleeved on the upper end of the lower die outside the product positioning pin; a drill die is installed between the upper and lower dies. This utility model achieves integrated curing of the prepreg flange and twisting process by using the combined use of the upper die, lower die, and drill die. The shape design of the upper die ensures the fiber continuity at the flange, avoiding structural weaknesses caused by fiber breakage or discontinuity, and improving the overall strength and reliability of the product. At the same time, the twist can be quantitatively filled, reducing the complexity of multi-step processing in the process, thereby ensuring the structural integrity and performance consistency of the product. Furthermore, the cured product only requires simple trimming before use, greatly simplifying subsequent processing procedures.

Description

Technical Field

[0001] This utility model relates to the field of aerospace technology, and in particular to a molding die for a composite material skin with a flange. Background Technology

[0002] Composite material skin parts are skin structures made of composite materials. The connection method of skin parts is mostly the connection in the thickness direction and normal direction of the skin. Because the thickness of composite parts is generally thin, usually within 5mm, the connection method along the thickness section direction is relatively rare. However, some parts need to be connected along the thickness section direction due to different operating conditions. The skin is made of composite materials, usually including carbon fiber reinforced composite materials, glass fiber composite materials, etc. These materials are formed through specific processes (such as prepreg laying, curing, etc.) and are widely used in aerospace and other fields, with many excellent properties and a wide range of applications.

[0003] Existing carbon fiber composite materials have low interlaminar strength. When drilling holes in the interlaminar direction, insufficient interlaminar bonding force can easily lead to delamination of the material, which can damage the structural integrity and load-bearing capacity, and affect the reliability and service life of the product. Utility Model Content

[0004] To overcome the problem that existing carbon fiber composite materials have low interlayer strength, and that insufficient interlayer bonding force can easily lead to material delamination during hole drilling operations in the interlayer direction, thereby damaging structural integrity and load-bearing capacity, affecting the reliability and service life of the product, and reducing overall safety, this utility model provides a molding die for a composite material skin with flanges.

[0005] The technical solution is as follows: A molding die for a composite material skin with a flanged edge includes an upper die, a lower die, and a drill die; a front insert is installed at the upper end of the lower die, the upper die is sleeved on the outer side of the product positioning pin at the upper end of the lower die, and a drill die is installed between the upper die and the lower die.

[0006] Furthermore, two sets of bosses are symmetrically installed on the inner wall of the lower mold below the front insert, and two sets of product positioning pins are symmetrically installed on the outer end of the lower mold.

[0007] Furthermore, bolts are installed on the outer end of the lower mold on one side of the product positioning pin, and multiple sets of drill bushings are fixed on the inner wall of the lower mold below the two sets of bosses.

[0008] Furthermore, the interior of the upper mold is provided with positioning holes to accommodate product positioning pins and to determine the installation position and orientation accuracy of the upper mold.

[0009] Furthermore, the upper mold has a threaded through hole on one side of the positioning hole to accommodate bolts. The upper mold is installed and fixed to the lower mold by product positioning pins and bolts.

[0010] Furthermore, the drill jig has a limiting hole inside to accommodate the boss, and a threaded hole inside the drill jig located on one side of the limiting hole to accommodate the bolt.

[0011] Furthermore, a gasket sleeve that matches the product positioning pin is provided on one side of the threaded hole inside the drill jig to ensure the accuracy of the product's hole drilling position.

[0012] The beneficial effects are as follows: This utility model achieves integrated curing and molding of prepreg by combining the use of an upper mold, a lower mold, and a drilling jig during processing, ensuring that the prepreg is folded and twisted in one piece. The shape design of the upper mold ensures the continuity of fibers at the fold, avoiding structural weaknesses caused by fiber breakage or discontinuity, and improving the overall strength and reliability of the product. At the same time, the twist can be quantitatively filled, reducing the complexity of multi-step processing in the process, thereby ensuring the structural integrity and performance consistency of the product. Secondly, the cured product only needs simple trimming before it can be put into use, which greatly simplifies the subsequent processing procedures. In addition, the position and accuracy of the holes are precisely ensured by the drilling jig, with the hole-making direction perpendicular to the layup direction, effectively avoiding the risk of splitting and improving the reliability and service life of the product. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of a molding die for a composite material skin with a flange, according to the present invention.

[0014] Figure 2 This is a schematic diagram of the three-dimensional structure of the lower mold of this utility model;

[0015] Figure 3 This is an exploded three-dimensional structural diagram of the lower mold of this utility model;

[0016] Figure 4 This is a three-dimensional structural diagram of the drill jig of this utility model.

[0017] In the attached diagram, the following are the reference numerals: 1. Upper mold; 2. Lower mold; 3. Drill jig; 4. Front insert; 5. Boss; 6. Product positioning pin; 7. Bolt; 8. Bushing; 9. Positioning hole; 10. Threaded through hole; 11. Limiting hole; 12. Threaded hole; 13. Gasket. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] Composite material skin components are crucial structural parts in modern aerospace, automotive, and other fields. They are primarily composed of high-strength, high-modulus reinforcing fibers such as carbon fiber, glass fiber, and aramid fiber, combined with a resin matrix (such as epoxy resin or bismaleimide resin) through specific processes, offering unique performance advantages and broad application prospects. These parts are typically sheet-like structures, with thicknesses ranging from a few millimeters to tens of millimeters, and their specific dimensions and shapes depend on various application requirements. In the aerospace field, composite material skin components are widely used in critical parts of aircraft such as wings, fuselages, and tail sections. Their function is not only to provide external protection for aircraft against environmental factors (such as wind, rain, hail, and bird strikes), but also to maintain a good aerodynamic shape and ensure aerodynamic performance during flight. For example, the skin components of aircraft wings need to precisely conform to the aerodynamic shape of the wing to reduce air resistance and improve fuel efficiency, while also withstanding various loads generated by airflow during flight, such as lift, shear force, and bending moment.

[0020] The manufacturing process of composite material skin parts is relatively complex and requires comprehensive consideration of multiple factors. Firstly, in terms of material selection, appropriate reinforcing fibers and resin matrices must be chosen based on different usage environments and performance requirements. For example, in the aerospace field, high-strength, high-modulus carbon fibers are typically combined with high-temperature resistant, high-strength resins to meet the performance requirements of aircraft in high-speed flight and complex environments. In the automotive field, however, cost-effectiveness may be a greater consideration, and relatively economical glass fiber composite materials may be selected while ensuring performance.

[0021] Secondly, during the design phase, advanced computer-aided design (CAD) and finite element analysis (FEA) technologies are required to accurately design the structure and evaluate the mechanical properties of the skin parts. By simulating different working conditions, parameters such as part thickness, layup angle, and number of layers are optimized to ensure that weight is reduced to the maximum extent while meeting strength and stiffness requirements. In the manufacturing process, common methods include manual layup, automated tape laying, and autoclave curing. Manual layup is suitable for parts with complex shapes and small dimensions, offering flexibility but lower efficiency; automated tape laying is suitable for large-area, regularly shaped parts, improving production efficiency and quality stability. Autoclave curing is currently the most commonly used curing process, which fully cures the resin under high temperature and pressure to form a composite material structure with good mechanical properties.

[0022] However, composite material skin parts also face some challenges and limitations. On the one hand, their manufacturing costs are relatively high, especially in the aerospace field, where the raw material and processing costs of high-performance composite materials are expensive, which limits their large-scale application to some extent. On the other hand, composite materials have high damage tolerance and are difficult to repair. Once damage occurs, such as delamination or fiber breakage, the repair process is complex and costly, requiring specialized equipment and technicians. Furthermore, the recycling of composite materials is a pressing issue. Currently, composite material recycling technologies are not mature enough, and most discarded composite material parts are difficult to effectively recycle and reuse, putting pressure on the environment.

[0023] With the continuous advancement of technology, the research and development of composite material skin parts is ongoing. Researchers are exploring new material systems, manufacturing processes, and design concepts to further improve performance, reduce costs, enhance damage tolerance, and increase recyclability. For example, novel nano-reinforced composite materials and self-healing composite materials are gradually finding applications, promising new breakthroughs in the development of composite material skin parts. Meanwhile, additive manufacturing (3D printing) technology is also showing broad application prospects in the field of composite materials, potentially enabling the rapid manufacturing and personalized customization of complex-shaped skin parts.

[0024] Composite material skin components, as high-performance and multifunctional structural parts, have broad application prospects in aerospace, automotive, and other fields. They can not only significantly improve the performance and efficiency of aircraft and automobiles, but also drive technological progress and sustainable development in related industries. Although some challenges remain, with continuous technological innovation and breakthroughs, composite material skin components will undoubtedly play an even more important role in the future.

[0025] like Figures 1-4 As shown, a molding die for a composite material skin with a flange includes an upper die 1, a lower die 2 and a drill die 3; a front insert 4 is installed at the upper end of the interior of the lower die 2, and the upper die 1 is sleeved on the upper end of the lower die 2 outside the product positioning pin 6; a drill die 3 is installed between the upper die 1 and the lower die 2.

[0026] Please see Figures 2-3Two sets of bosses 5 are symmetrically installed on the inner wall of the lower mold 2 below the front insert 4. Two sets of product positioning pins 6 are symmetrically installed on the outer end of the lower mold 2. The bosses 5 are used to ensure that the countersunk hole at the product connection point is co-cured with the product. After curing, the drill dies 3 are installed to complete the preparation of the connection hole, which helps the gasket 13 to ensure that the countersunk hole at the connection point is concentric with the bosses 5. Bolts 7 are installed on the outer end of the lower mold 2 on one side of the product positioning pins 6. Multiple sets of drill die 3 bushings 8 are fixed on the inner wall of the lower mold 2 below the two sets of bosses 5. The upper mold 1 has positioning holes 9 inside to accommodate the product positioning pins 6 and to determine the installation position and orientation accuracy of the upper mold 1. The use of the upper mold 1 can ensure that the fiber at the product flange is continuous and integrally formed with a net size, thus ensuring the strength of the installation position.

[0027] Please see Figures 2-4 The upper mold 1 has a threaded through hole 10 for accommodating bolt 7 on one side of the positioning hole 9. The upper mold 1 is installed and fixed to the lower mold 2 by the product positioning pin 6 and bolt 7. The structure of the upper mold 1 can help the surface fiber direction of the flanging prepreg to be perpendicular to the normal direction of the hole making position, instead of making the hole in the interlayer direction of the product, effectively preventing the hole making position from splitting along the interlayer direction. The drill jig 3 has a limiting hole 11 for accommodating boss 5 inside. The drill jig 3 has a threaded hole 12 for accommodating bolt 7 on one side of the limiting hole 11 inside. The drill jig 3 has a liner sleeve 13 on one side of the threaded hole 12 inside, which is adapted to the product positioning pin 6 to ensure the accuracy of the product hole making position.

[0028] When manufacturing composite material skin parts, the upper mold 1 and lower mold 2 are first assembled to form a complete mold system. Next, the first layer of prepreg is laid inside the cavity of the lower mold 2, ensuring the prepreg adheres tightly to the surface of the cavity. A flanging operation is performed on the bottom surface of the upper mold 1, guiding the first layer of prepreg to form the desired flanged shape. Subsequently, carbon fiber prepreg twists and subsequent layups are used to gradually fill the space between the upper mold 1 and lower mold 2, ensuring each layer of prepreg adheres tightly to the mold surface, forming a uniform layered structure. After the prepreg is laid, a curing process is performed to solidify the prepreg within the mold. After curing, auxiliary materials such as release cloth are removed. The upper mold 1 is removed without demolding, and a drill 3 is installed in the position of the upper mold 1 to precisely drill holes. After drilling, the product is removed from the mold, and its outer contour is trimmed to ensure the product's shape meets design requirements. Throughout the manufacturing process, the direction of hole drilling is consistent with the direction of layer layup, which can effectively prevent splitting and ensure the production quality of the product.

[0029] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A forming tool for a composite material skin with a flange, characterized in that, It includes an upper mold (1), a lower mold (2) and a drill jig (3); the upper part of the lower mold (2) is equipped with a front insert (4), the upper part of the lower mold (2) is fitted with the upper mold (1) outside the product positioning pin (6), and the drill jig (3) is installed between the upper mold (1) and the lower mold (2).

2. A forming tool for a composite material skin with flanges according to claim 1, characterized in that The inner wall of the lower mold (2) is symmetrically equipped with two sets of bosses (5) below the front insert (4), and the outer end of the lower mold (2) is symmetrically equipped with two sets of product positioning pins (6).

3. A forming tool for a composite skin with flanges according to claim 2, characterized in that The outer end of the lower mold (2) is equipped with a bolt (7) on one side of the product positioning pin (6), and multiple sets of drill jig (3) bushings (8) are fixed below the two sets of bosses (5) on the inner wall of the lower mold (2).

4. A forming tool for a composite skin with flanges according to claim 1, characterized in that The upper mold (1) is provided with positioning holes (9) to accommodate product positioning pins (6) and to determine the installation position and orientation accuracy of the upper mold (1).

5. A forming tool for a composite material skin with flanges according to claim 4, characterized in that The upper mold (1) has a threaded through hole (10) for accommodating bolts (7) on one side of the positioning hole (9). The upper mold (1) is installed and fixed to the lower mold (2) by product positioning pins (6) and bolts (7).

6. A forming tool for a composite skin with flanges according to claim 1, characterized in that The drill jig (3) has a limiting hole (11) inside to accommodate the boss (5), and a threaded hole (12) inside the drill jig (3) on one side of the limiting hole (11) to accommodate the bolt (7).

7. A forming tool for a composite material skin with flanges according to claim 6, characterized in that A liner (13) is provided on one side of the threaded hole (12) inside the drill jig (3) to match the product positioning pin (6) and to ensure the accuracy of the product hole making position.

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