Carbon fiber composite material cartridge forming tool for aviation, cartridge and forming method thereof

Abstract

The application provides an aviation carbon fiber composite magazine forming tool, a magazine and a forming method thereof. The forming tool comprises a fixed base, a plurality of square tube forming cores and a plurality of connecting block forming cores. Each square tube forming core is detachably connected to the fixed base, and the outer cover layers of two adjacent square tube forming cores are connected to each other. Each connecting block forming core is detachably connected to the fixed base, and the outer cover layer of each connecting block forming core is connected to the outer cover layer of the adjacent square tube forming core. The square tube forming cores and the connecting block forming cores are surrounded to form a profile, and a layer of carbon fiber prepreg for forming a magazine shell is laid on the profile. In the application, the forming tool adopts a split structure, the square tube forming cores and the connecting block forming cores can be taken down, and then the material laying and the material preforming treatment are carried out, and then the square tube forming cores and the connecting block forming cores are installed on the fixed base, so that the material laying effect is guaranteed, and the overall forming quality of the magazine is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ammunition magazines, in particular to an aviation carbon fiber composite material ammunition magazine forming tool, an aviation carbon fiber composite material ammunition magazine and a forming method of the aviation carbon fiber composite material ammunition magazine. BACKGROUND

[0002] The ammunition magazine is an important aviation part, is a loading body of airborne jamming ammunition, and has the characteristics of complex structure. In the traditional technology, the ammunition magazine is usually made of high-strength aluminum alloy and titanium alloy and the like metal, has the defects of large mass, high cost, limited designability by machining process, poor corrosion resistance and poor mechanical properties, and the forming method of the metal ammunition magazine has the defect of complex production process. Therefore, people began to use composite materials to prepare the ammunition magazine to overcome the defects of the traditional technology.

[0003] However, the existing composite material ammunition magazine forming tool is of a whole structure, and directly laying the material on the whole structure forming tool has the defect of inconvenient operation, which further reduces the forming quality of the ammunition magazine. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the defects of the prior art, provide an aviation carbon fiber composite material ammunition magazine forming tool capable of improving the forming quality of the ammunition magazine, an aviation carbon fiber composite material ammunition magazine with good forming quality, and a forming method of the carbon fiber composite material ammunition magazine capable of improving the forming quality of the ammunition magazine.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] An aviation carbon fiber composite material ammunition magazine forming tool, comprising a fixed base; a plurality of square tube forming cores with preformed carbon fiber prepreg and adhesive film on the outer surface are detachably connected to the fixed base, and four connecting block forming cores with preformed carbon fiber prepreg and adhesive film on the outer surface are detachably connected to the fixed base, the plurality of square tube forming cores and the four connecting block forming cores are arranged in a square structure on the fixed base, and the square structure is used for laying carbon fiber prepreg to form an ammunition magazine shell.

[0007] Further, the forming tool comprises a plug-in plate, a plurality of plug-in holes are formed in the plug-in plate; an installation groove is formed in the fixed base, and the plug-in plate is installed in the installation groove; the square tube forming cores and the connecting block forming cores are plugged into the plug-in holes of the plug-in plate.

[0008] Further, the forming tooling comprises a press-in board, a plurality of insertion holes are formed on the press-in board; the end of the square tube forming mold core away from the fixed base and the end of the connecting block forming mold core away from the fixed base are fixedly installed in the insertion holes of the press-in board.

[0009] Further, the forming tooling comprises a magazine shell forming mold, the magazine shell forming mold comprises four forming plates; the four forming plates are slidingly arranged on the fixed base and can be used to extrude the square structure so that the carbon fiber prepreg laid on the square structure and the preformed carbon fiber prepreg are combined by the adhesive film.

[0010] Further, one side of the forming plate facing the external space is a bevel, and the forming tooling comprises a press cover; the press cover is connected with the fixed base and can also be used to press the bevel of the forming plate and the press-in board.

[0011] Further, the forming tooling comprises a square tube preforming mold set; the square tube preforming mold set comprises a first lower mold base and a first upper mold cover; a square groove capable of accommodating a plurality of square tube forming mold cores with carbon fiber prepreg laid on the outer surface is formed between the first lower mold base and the first upper mold cover; the first lower mold base is connected with the first upper mold cover and can extrude the carbon fiber prepreg on the outer surface of the square tube forming mold core.

[0012] Further, the forming tooling comprises a connecting block preforming mold set; the connecting block preforming mold set comprises a second lower mold base and a second upper mold cover; a forming groove capable of accommodating a plurality of connecting block forming mold cores covered with carbon fiber prepreg on the outer surface is formed between the second lower mold base and the second upper mold cover; the second lower mold base is connected with the second upper mold cover and can extrude the carbon fiber prepreg on the outer surface of the connecting block forming mold core.

[0013] Further, the connecting block forming mold core comprises three first, second and third rod members inserted in sequence; the cross-sectional area of the first rod member and the cross-sectional area of the third rod member are both smaller than the cross-sectional area of the second rod member.

[0014] A carbon fiber composite magazine for aviation is prepared by using the forming tooling described above; the connecting block forming mold core comprises three first, second and third rod members inserted in sequence; the magazine comprises a magazine shell and four connecting blocks, the four connecting blocks are correspondingly connected to the four corners on the inner side of the magazine shell; a demolding groove for taking out the second rod member is formed on the side wall of the magazine shell; a first demolding hole for taking out the first rod member is formed on one end of the connecting block, and a second demolding hole for taking out the third rod member is formed on the other end.

[0015] A method for molding a carbon fiber composite magazine for aviation use, applied to the molding tooling described above; comprising the following steps:

[0016] S1: Remove the square tube forming mold core and the connecting block forming mold core from the fixed base, lay carbon fiber prepreg on the outer surface of the two and perform pre-forming treatment, and then lay the adhesive film to obtain a square tube forming mold core covered with pre-formed carbon fiber prepreg and adhesive film and a connecting block forming mold core covered with pre-formed carbon fiber prepreg and adhesive film.

[0017] S2: Install the square tube forming mold core covered with pre-formed carbon fiber prepreg and film and the connecting block forming mold core covered with pre-formed carbon fiber prepreg and film on the fixed base, and arrange the square tube forming mold core covered with pre-formed carbon fiber prepreg and film and the connecting block forming mold core covered with pre-formed carbon fiber prepreg and film to form a square structure.

[0018] S3: Apply carbon fiber prepreg to the outline of the square structure, excluding the top and bottom.

[0019] S4: Place the molding fixture on the curing platform of the hot press, and heat and press the square tube molding core covered with pre-formed carbon fiber prepreg and adhesive film, and the connecting block molding core covered with pre-formed carbon fiber prepreg and adhesive film, and then mold and cure them.

[0020] Compared with the prior art, the advantages of the present invention are as follows: the molding tooling adopts a split structure, which can remove the square tube molding core and the connecting block molding core, perform material laying and material preforming treatment respectively, and then install them on the fixed base to form the square structure. Then, carbon fiber prepreg is laid on the square structure to form the magazine shell, which ensures the effect of material laying and thus improves the overall molding quality of the magazine. Attached Figure Description

[0021] Figure 1 This is an exploded view of a carbon fiber composite magazine molding tooling for aviation use;

[0022] Figure 2 This is a schematic diagram of the structure of the square tube preforming module in the aviation carbon fiber composite magazine forming tooling;

[0023] Figure 3 This is a schematic diagram of the connecting block pre-forming module in the molding tooling for carbon fiber composite magazines used in aviation.

[0024] Figure 4 This is a schematic diagram of the connecting block forming mold core in the molding tooling for carbon fiber composite magazines used in aviation.

[0025] Figure 5is a structural schematic diagram of a carbon fiber composite magazine for aviation;

[0026] Figure 6 is a flow chart of a forming method of a carbon fiber composite magazine for aviation.

[0027] In the figure, the numbers represent: 1, fixed base; 2, square tube forming mold core; 3, connecting block forming mold core; 301, first rod; 302, second rod; 303, third rod; 4, plug-in plate; 5, pressurized plug-in plate; 6, magazine shell forming mold; 601, forming plate; 7, pressurized cover; 8, square tube preforming mold set; 801, first lower mold base; 802, first upper mold cover; 9, connecting block preforming mold set; 901, second lower mold base; 902, second upper mold cover; 10, magazine shell; 11, connecting block; 12, square tube; 13, metal embedded part. DETAILED DESCRIPTION

[0028] The application will be further described in detail below in combination with the drawings and specific examples.

[0029] An embodiment of a forming tool for a carbon fiber composite magazine for aerospace applications

[0030] Please refer to Figures 1-4 , the carbon fiber composite magazine forming tool for aviation includes a fixed base 1; a plurality of square tube forming mold cores 2 and four connecting block forming mold cores 3, the outer surfaces of which are covered with preformed carbon fiber prepreg and adhesive film, are detachably connected to the fixed base 1; the plurality of square tube forming mold cores 2 and the four connecting block forming mold cores 3 are arranged in a square structure on the fixed base 1 and are used for laying carbon fiber prepreg to form a magazine shell. The adhesive film includes epoxy resin or bismaleimide resin, and the thickness of the adhesive film is 0.1-0.2mm. The carbon fiber prepreg includes medium-temperature curing carbon fiber prepreg or high-temperature curing carbon fiber prepreg. The forming tool adopts a split structure, the square tube forming mold cores 2 and the connecting block forming mold cores 3 can be taken off, laid with material and preformed separately, and then installed on the fixed base 1 to form the square structure, and then laid with carbon fiber prepreg to form a magazine shell, which ensures the effect of material laying and improves the overall forming quality of the magazine. In addition, after separating the parts of the forming tool, each part is laid separately, modular operation is adopted, the laying difficulty is reduced, the work efficiency is improved, and the rapid batch production of the magazine is facilitated.

[0031] Specifically, the forming tooling includes a plug-in plate 4, a plurality of insertion holes are formed on the plug-in plate 4; the fixing base 1 is provided with a mounting groove, the plug-in plate 4 is mounted in the mounting groove; the square tube forming mold core 2 and the connecting block forming mold core 3 are inserted into the insertion holes of the plug-in plate 4. The square tube forming mold core 2 and the connecting block forming mold core 3 are connected with the fixing base 1 through the plug-in plate 4, which has the advantage of convenient disassembly and assembly. Further, the mounting groove is provided with an error-proof positioning assembly to facilitate the positioning and installation of the plug-in plate 4, and the mounting groove is provided with an exhaust groove and a semicircular overflow groove, which can exhaust excess gas and resin to improve the forming quality.

[0032] Specifically, the forming tooling includes a plug-in plate 4, a plurality of insertion holes are formed on the plug-in plate 4; the fixing base 1 is provided with a mounting groove, the plug-in plate 4 is mounted in the mounting groove; the square tube forming mold core 2 and the connecting block forming mold core 3 are inserted into the insertion holes of the plug-in plate 4. The square tube forming mold core 2 and the connecting block forming mold core 3 are connected with the fixing base 1 through the plug-in plate 4, which has the advantage of convenient disassembly and assembly. Further, the mounting groove is provided with an error-proof positioning assembly to facilitate the positioning and installation of the plug-in plate 4, and the mounting groove is provided with an exhaust groove and a semicircular overflow groove, which can exhaust excess gas and resin to improve the forming quality. Specifically, the forming tooling includes a plug-in plate 4, a plurality of insertion holes are formed on the plug-in plate 4; the fixing base 1 is provided with a mounting groove, the plug-in plate 4 is mounted in the mounting groove; the square tube forming mold core 2 and the connecting block forming mold core 3 are inserted into the insertion holes of the plug-in plate 4. The square tube forming mold core 2 and the connecting block forming mold core 3 are connected with the fixing base 1 through the plug-in plate 4, which has the advantage of convenient disassembly and assembly. Further, the mounting groove is provided with an error-proof positioning assembly to facilitate the positioning and installation of the plug-in plate 4, and the mounting groove is provided with an exhaust groove and a semicircular overflow groove, which can exhaust excess gas and resin to improve the forming quality.

[0033] Specifically, the molding fixture includes a square tube preforming module 8; the square tube preforming module 8 includes a first lower mold base 801 and a first upper mold cover 802; a square groove is formed between the first lower mold base 801 and the first upper mold cover 802 to accommodate multiple square tube forming mold cores 2 with carbon fiber prepreg on their outer surfaces; the first lower mold base 801 is connected to the first upper mold cover 802 and can compress the carbon fiber prepreg on the outer surface of the square tube forming mold core 2. The molding fixture includes a connecting block preforming module 9; the connecting block preforming module 9 includes a second lower mold base 901 and a second upper mold cover 902; a molding groove is formed between the second lower mold base 901 and the second upper mold cover 902 to accommodate multiple connecting block forming mold cores 3 with carbon fiber prepreg on their outer surfaces; the second lower mold base 901 is connected to the second upper mold cover 902 and can compress the carbon fiber prepreg on the outer surface of the connecting block forming mold core 3. Through the combined action of the square tube preforming module 8 and the connecting block preforming module 9, multiple square tube preforms and multiple connecting block preforms can be quickly obtained, achieving modularity and simplifying operation, thus facilitating rapid mass production of magazines. Furthermore, the connecting block forming core 3 includes three sequentially inserted first rods 301, 302, and 303; the cross-sectional areas of the first rod 301 and the third rod 303 are both smaller than the cross-sectional area of ​​the second rod 302, and the end of the first rod 301 furthest from the second rod 302 is fixedly connected to the pressure insertion plate 5, while the end of the third rod 303 furthest from the second rod 302 is inserted into the insertion plate 4. Furthermore, both ends of the square tube forming mold core 2 are formed with draft tapers. The end of the first rod 301 away from the second rod 302 and the end of the third rod 303 away from the second rod 302 are both formed with draft tapers. The draft taper is 8-20°, which facilitates the use of a drafting tool to achieve quick drafting. The second rod 302 is provided with a threaded hole on its side. After the magazine shell is formed, a draft groove is opened on its side to facilitate the removal of the second rod 302 from the draft groove by a puller.

[0034] An embodiment of a carbon fiber composite magazine for aerospace applications

[0035] Please refer to Figure 5The aviation carbon fiber composite magazine is prepared by using the forming tool mentioned above; the connecting block forming mold core 3 comprises three sequentially inserted first rod 301, second rod 302 and third rod 303; the magazine comprises a magazine shell 10 and four connecting blocks 11, and the four connecting blocks 11 are connected to the four corners of the inner side of the magazine shell 10; the side wall of the magazine shell 10 is provided with a demolding groove for taking out the second rod 302, and the demolding groove also plays a role in reducing the weight of the device as a whole; one end of the connecting block 11 is provided with a first demolding hole for taking out the first rod 301, and the other end is provided with a second demolding hole for taking out the third rod 303. Specifically, the magazine further comprises a plurality of square tubes 12; a plurality of square tubes 12 are arranged on the inner side of the magazine shell 10, and a plurality of square tubes 12 are connected as a whole and connected with the magazine shell 10 and the connecting block 11. Further, a metal embedded part 13 is arranged in each connecting block 11, and an internal thread is formed on the metal embedded part 13. In the prior art, an internal thread is usually formed on the connecting block 11 to connect with the external device, but since the connecting block 11 is made of composite material, the wear resistance is not high, resulting in unreliable connection. In the present application, the metal embedded part 13 is arranged in the connecting block 11, and the internal thread of the metal embedded part 13 is connected with the external device, which improves the wear resistance, connection reliability and repeatable disassembly. Among them, the metal embedded part 13 comprises an aluminum alloy embedded part, a titanium alloy embedded part or a magnesium alloy embedded part.

[0036] An embodiment of a method of forming a carbon fiber composite magazine for aerospace applications

[0037] Please refer to Figure 6 The forming method of the aviation carbon fiber composite magazine is applied to the forming tool mentioned above; comprising the following steps:

[0038] S1: the square tube forming mold core 2 and the connecting block forming mold core 3 are taken off from the fixed base 1, the outer surfaces of the two are paved with carbon fiber prepreg and preformed, then the glue film is paved, and the square tube forming mold core 2 covered with preformed carbon fiber prepreg and glue film and the connecting block forming mold core 3 covered with preformed carbon fiber prepreg and glue film are obtained. Among them, the preforming treatment is realized by using the square tube preforming mold group 8 and the connecting block preforming mold group 9: the outer surfaces of the square tube forming mold core 2 and the connecting block forming mold core 3 are paved with carbon fiber prepreg and precompacted in a vacuum environment, and the vacuum degree of the environment is not less than-0.085MPa, the precompaction time is not less than 5min, the paving of carbon fiber prepreg is carried out in a purification room, and the environmental temperature of the purification room is 18-26℃, the relative humidity is not greater than 65%, and the illuminance is not less than 200Lux; the square tube forming mold core 2 is installed between the first lower mold seat 801 and the first upper mold cover 802, the connecting block forming mold core 3 is installed between the second lower mold seat 901 and the second upper mold cover 902, then the square tube preforming mold group 8 and the connecting block preforming mold group 9 are transferred to the press, the square tube preforming mold group 8 is applied with a pressure of 20-40T for 3-5min, and the connecting block preforming mold group 9 is applied with a pressure of 10-20T for 3-5min, and the square tube preforming body and the connecting block preforming body are obtained by mold pressing preforming.

[0039] S2: the square tube forming mold core 2 covered with preformed carbon fiber prepreg and glue film and the connecting block forming mold core 3 covered with preformed carbon fiber prepreg and glue film are installed on the fixed base 1, and the square tube forming mold core 2 covered with preformed carbon fiber prepreg and glue film and the connecting block forming mold core 3 covered with preformed carbon fiber prepreg and glue film are arranged to form a square structure.

[0040] S3: carbon fiber prepreg is paved on the outline of the square structure except the top and bottom. After paving the carbon fiber prepreg, precompaction is carried out in a vacuum environment, and the vacuum degree of the environment is not less than-0.085MPa, and the precompaction time is not less than 5min.

[0041] S4: the magazine shell forming mold 6 is arranged on the fixed base 1, so that the magazine shell forming mold 6 surrounds the square tube forming mold core 2 covered with preformed carbon fiber prepreg and glue film and the connecting block forming mold core 3 covered with preformed carbon fiber prepreg and glue film; and the pressurizing plug-in plate 5 and the pressurizing cover 7 are installed.

[0042] S5: The forming tool is placed on the curing platform of the hot press, and the square tube forming mold core 2 covered with preformed carbon fiber prepreg and adhesive film and the connecting block forming mold core 3 covered with preformed carbon fiber prepreg and adhesive film are heated and pressed by the cartridge shell forming mold 6, the press-in plate 5 and the press-in cover 7, and are molded and cured. When the carbon fiber prepreg is selected as medium temperature curing carbon fiber prepreg, the cartridge curing parameters are: slowly pressurized to 10T (contact pressure), increased to 75-85℃ at a rate of 1-3℃ / min, and kept at temperature and pressure for 10-30min; continue to increase the temperature to 125-135℃ at a rate of 1-3℃ / min, when the temperature reaches 105-115℃, pressurize to 140T, keep temperature and pressure for 20-60min; decrease the temperature to below 60℃ at a rate of 1-3℃ / min, and then release the pressure. When the carbon fiber prepreg is selected as high temperature curing carbon fiber prepreg, the cartridge curing parameters are: slowly pressurized to 10T (contact pressure), increased to 90-100℃ at a rate of 1-3℃ / min, and kept at temperature and pressure for 10-30min; continue to increase the temperature to 175-185℃ at a rate of 1-3℃ / min, when the temperature reaches 115-125℃, pressurize to 140T, keep temperature and pressure for 120-180min; decrease the temperature to below 80℃ at a rate of 1-3℃ / min, and then release the pressure.

[0043] S6: Demolding, taking out the formed cartridge, and sequentially taking out the first rod 301, the third rod 303 and the second rod 302.

[0044] S7: Trim the burrs on the cartridge, and polish to smooth and smooth with sandpaper.

[0045] S8: Process the formed cartridge on the three-axis numerical control machining center to form grooves or holes for weight reduction and external connecting holes.

[0046] S9: Spray paint on the outer surface of the cartridge. The paint is a composite color acrylic polyurethane semi-gloss paint, which requires 2 coats of paint, each coat has a thickness of 20-25μm, and the coating surface should be uniform, without bubbles, no leakage, no obvious flow, no orange peel, no impurities, no cracks and other defects.

[0047] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any skilled person in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the technical solutions of the present application, shall fall within the scope of protection of the technical solutions of the present application.

Claims

1. An aviation carbon fiber composite magazine forming tooling, characterized by, The forming tool includes a fixed base (1), a plurality of square tube forming cores (2) covered with preformed carbon fiber prepreg and adhesive film, and a plurality of connecting block forming cores (3) covered with preformed carbon fiber prepreg and adhesive film; each of the square tube forming cores (2) is detachably connected to the fixed base (1) in the form of multiple rows and multiple columns, and a notch is arranged at the intersection of the outermost row and column, and the outer cover layers of two adjacent square tube forming cores (2) are connected to each other; each of the connecting block forming cores (3) is arranged at the corresponding notch, and each of the connecting block forming cores (3) is detachably connected to the fixed base (1), and the outer cover layer of each connecting block forming core (3) is connected to the outer cover layer of the square tube forming core (2) adjacent to the corresponding notch. The square tube forming cores (2) located in the outermost row and column and the connecting block forming cores (3) at each notch are surrounded to form a profile except the top and bottom, and a layer of carbon fiber prepreg for forming a magazine shell (10) is laid on the profile.

2. The carbon fiber composite magazine forming tooling for aerospace applications of claim 1, wherein, The forming tool includes a plug-in plate (4) having a plurality of plug-in holes formed therein; the fixed base (1) has a mounting groove, and the plug-in plate (4) is mounted in the mounting groove; and the square tube forming cores (2) and the connecting block forming cores (3) are detachably plugged into the plug-in holes of the plug-in plate (4).

3. The carbon fiber composite magazine forming tooling for aerospace applications of claim 1, wherein, The forming tool includes a pressurized plug-in plate (5) having a plurality of plug-in holes formed therein; one end of each of the square tube forming cores (2) and the connecting block forming cores (3) away from the fixed base (1) is fixedly mounted in the plug-in hole of the pressurized plug-in plate (5).

4. The carbon fiber composite magazine forming tooling for aerospace applications of claim 3, wherein, The forming tool includes a magazine shell forming die (6) including a plurality of forming plates (601); each of the forming plates (601) is slidably arranged on the fixed base (1) to press the carbon fiber prepreg for forming the magazine shell (10).

5. The carbon fiber composite magazine forming tooling for aerospace applications of claim 4, wherein, One side of the forming plate (601) facing the external space is a bevel; the forming tool includes a pressurized cover (7) connected to the fixed base (1), and the pressurized cover (7) covers the pressurized plug-in plate (5) and the magazine shell forming die (6) to press the bevel of the pressurized plug-in plate (5) and the forming plate (601).

6. The carbon fiber composite magazine forming tooling for aerospace applications of any one of claims 1-5, wherein, The forming tool includes a square tube preforming die set (8); the square tube preforming die set (8) includes a first lower die seat (801) and a first upper die cover (802); a square slot capable of accommodating a plurality of square tube forming cores (2) having carbon fiber prepreg laid on the outer surfaces is formed between the first lower die seat (801) and the first upper die cover (802); The first lower die seat (801) is connected to the first upper die cover (802) and can press the carbon fiber prepreg on the outer surface of the square tube forming core (2).

7. The carbon fiber composite magazine forming tooling for aerospace applications of any one of claims 1-5, wherein, The forming tool includes a connecting block preforming module (9); the connecting block preforming module (9) includes a second lower die seat (901) and a second upper die cover (902); a forming groove capable of accommodating a plurality of connecting block forming cores (3) whose outer surfaces are covered with carbon fiber prepreg is formed between the second lower die seat (901) and the second upper die cover (902); the second lower die seat (901) is connected with the second upper die cover (902) and can extrude the carbon fiber prepreg on the outer surface of the connecting block forming core (3).

8. The carbon fiber composite magazine forming tooling for aerospace applications of claim 7, wherein, The connecting block forming core (3) includes three first, second and third rod members (301, 302 and 303) which are sequentially inserted; the cross-sectional area of the first rod member (301) and the cross-sectional area of the third rod member (303) are both smaller than the cross-sectional area of the second rod member (302).

9. A method of forming an aviation carbon fiber composite magazine, characterized by, The application is applied to the forming tool as claimed in any one of claims 1-8; and includes the following steps: S1: the square tube forming core (2) and the connecting block forming core (3) are taken off from the fixed base (1), carbon fiber prepreg is laid on the outer surfaces of both, and preforming treatment is performed, then adhesive film is laid, to obtain a square tube forming core (2) covered with preformed carbon fiber prepreg and adhesive film and a connecting block forming core (3) covered with preformed carbon fiber prepreg and adhesive film; S2: the square tube forming core (2) covered with preformed carbon fiber prepreg and adhesive film and the connecting block forming core (3) covered with preformed carbon fiber prepreg and adhesive film are installed on the fixed base (1), and the square tube forming core (2) covered with preformed carbon fiber prepreg and adhesive film and the connecting block forming core (3) covered with preformed carbon fiber prepreg and adhesive film are arranged to form a square structure; S3: carbon fiber prepreg is laid on the contour of the square structure except the top and bottom; S4: the forming tool is placed on the curing platform of a hot press, the square tube forming core (2) covered with preformed carbon fiber prepreg and adhesive film and the connecting block forming core (3) covered with preformed carbon fiber prepreg and adhesive film are heated and pressurized, and are molded and cured.

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