One-time forming method and mold for producing foam sandwich structure product from composite material

Abstract

The invention relates to the technical field of composite material manufacturing, in particular to a one-time forming method and a mold for producing a foam sandwich structure product from a composite material, epoxy foaming foam and carbon fiber prepreg are used as raw materials, a one-time forming compression molding process is adopted, the integrity and the structural property of the product are improved, and the production efficiency is improved. The performance of each part of the product in the use process is more uniform and stable, the production procedures and operation links are reduced, the production cycle is shortened, and the production efficiency is improved; a one-time forming process is adopted, so that deformation and shrinkage of the material are controlled under a unified process condition, and the dimensional accuracy of a product is better ensured; the foam density is controlled by adjusting the quality of the filled foaming foam, so that the diversified requirements of the composite material on the performance of an interlayer product are met, the designability of the product is enhanced, the diversified performance requirements are met, and a more efficient and high-quality production process is provided for related industries.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material production technology, and specifically to a one-time molding method and mold for producing foam sandwich structure products from composite materials. The method can be widely used in industries such as aerospace, drone manufacturing, etc. that have high performance requirements for composite material structural parts. Background Art

[0002] Due to the excellent properties of light weight and high strength, the application of composite materials is no longer limited to simple plates and shell structures. With the improvement of the performance and quality requirements of composite materials in the aerospace field, products with complex cavity structures such as special-shaped pipes and aircraft parts for aviation have also begun to be manufactured in large quantities using composite materials. For thicker or special-shaped composite parts, the filling core material used to be mainly honeycomb sandwich or foamed high-density foam. For some secondary load-bearing products, the filling core material is PES (polyethersulfone) foam, PMI (polymethacrylimide) foam, etc. When using them as sandwich layers, in order to fit the surface, the foam needs to be pre-pressed or pre-processed by machining. The pre-pressing and machining processes will incur corresponding costs. Due to the existence of machining errors, the fit between the skin layer and the mold will be affected to a certain extent. The need for resin filling is also prone to overweight. In the traditional production process of composite foam sandwich structure products, multiple molding processes are often required, such as making each component separately, and then assembling and secondary processing. This traditional process has many disadvantages: first, due to the existence of multiple molding steps and component connection processes, defects are easily generated at the interfaces between components, affecting the integrity and structural strength of the product and reducing the reliability of the product when subjected to stress and pressure; second, multiple processes lead to long production cycles, low production efficiency, and increased production costs. In the secondary molding process, steps such as waiting for the material to solidify and reheating will consume a lot of time, making the production process discontinuous; third, in the multiple molding process, due to the differences in process conditions in different processes, it is difficult to accurately control the dimensional accuracy of the product, and it is often difficult to meet the design requirements for parts with complex shapes and high precision requirements; in addition, the traditional process has limited design flexibility for product performance, and it is difficult to easily design structures with different performance characteristics according to the stress conditions of different parts of the product, and it is also not easy to meet the diversified performance requirements of sandwich products, such as precise control of foam density to achieve weight reduction and other purposes.

[0003] In order to solve the shortcomings of the above-mentioned composite products, such as complicated processes, high costs, long production cycles, and easy overweight of products, the present invention aims to provide a new one-time molding process for composite material production of foam sandwich structure products, creating a new economic growth point. Summary of the invention

[0004] The present invention provides a one-time molding method and mold for producing foam sandwich structure products from composite materials, so as to improve the integrity, structural strength, production efficiency and dimensional accuracy of the products, enhance the designability of the products, meet diverse performance requirements, and provide a more efficient and high-quality production process for related industries.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a one-step molding method for producing a foam sandwich structure product from a composite material, comprising the following steps: Step 1: Mold pretreatment: The composite product mold includes an upper mold, a lower mold and a bottom plate mold. Before production, the composite product mold is processed to ensure that the mold surface is smooth and heated, and a release agent is evenly applied on the mold surface; Step 2: Laying carbon fiber prepreg on the upper mold; Laying two layers of carbon fiber prepreg on the upper mold of the mold respectively; Step 3: The lower mold is paved with carbon fiber prepreg; two layers of carbon fiber prepreg are paved on the lower mold of the mold respectively, a circle of inward turning edges are reserved around the carbon fiber prepreg paved by the lower mold, and a reinforcement layer is pasted on the flange of the lower mold, and the reinforcement layer is pasted on the first layer and the second layer; Step 4: Lay the carbon fiber prepreg on the bottom plate mold; Use the same grade of carbon fiber prepreg leftovers to lay the bottom plate mold of the mold, and the laid carbon fiber prepreg is flush with the outer edge of the bottom plate mold; Step 5: cold pre-extraction: placing the upper mold, lower mold and bottom plate mold after the carbon fiber prepreg is laid in a vacuum package for cold pre-extraction in the workshop; Step 6: Laying the foam material: Evenly lay a layer of epoxy foam in the lower mold; When paving the foam, the edge area and each corner must be affixed to the foam material, and more foam material should be affixed to the thicker area of ​​the composite product; Step 7: Auxiliary paving of the upper mold; lay a strip of epoxy foam at the corner where the upper mold contacts the flange, and do not lay it at the flange; Step 8: Mold closing; combine the bottom plate mold with the upper mold and the lower mold, and fix them with screws; Step 9: Hot pressing: preheat the press to 135℃~140℃, put the mold into the press after mold closing, and pressurize it to 10MPa. After the mold is heated to 135℃~140℃, keep it for 30min and then start cooling. Do not release the pressure during the whole cooling process. Step 10: Post-processing steps; wait for the mold to cool down to below 40°C, release the pressure and remove the mold, first drill a hole at the flange, then open the mold; take out the qualified products and send them to the fitter for repair.

[0006] In the step 1, the mold surface is coated with a release agent three times, with an interval of 10 to 15 minutes between each coat, and finally the mold is heated at a temperature of 40 to 50°C. In the steps 2 and 3, the first layer of carbon fiber prepreg is pasted with 45° carbon fiber prepreg, and the second layer of carbon fiber prepreg is pasted with 0° carbon fiber prepreg. There are no specific requirements for the angles in other places.

[0007] In the step 3, the width of the inward flange reserved around the carbon fiber prepreg laid on the lower mold is 9 to 10 mm.

[0008] The surface density of the carbon fiber prepreg used in step 2, step 3 and step 4 is 330g±10g, wherein the surface density of the carbon fiber is 200±10g, and the resin content is 40%±2.

[0009] In the step 5, the cold pre-pumping time is 35 to 40 minutes.

[0010] In the step 5, before pre-drawing, a circle of flange around the lower mold is isolated from the lower mold by an isolation fabric.

[0011] The foam used in step 6 and step 7 is an epoxy resin system, with a thermal natural expansion ratio of 50 times, a starting temperature of 100°C to 150°C, and an epoxy foam filling density of 60 to 100 kg / m 3 , and isotropic.

[0012] In the step eight, when closing the mold, first turn the flange around the lower mold inward along the edge of the mold to ensure that the material is completely in the mold cavity when closing the mold, and the flange can wrap the foaming material; after closing the mold, lift the flange of the lower mold upward to ensure that the carbon fiber prepreg of the upper mold and the lower mold fit together.

[0013] A mold used in a one-time molding method for producing a foam sandwich structure product from a composite material, the mold comprising an upper mold, a lower mold and a bottom plate mold. After carbon fiber prepreg is laid on the molds and foamed foam is placed in them, the bottom plate mold is combined with the upper mold and the lower mold and fixed with screws to ensure that the product is molded in one time.

[0014] ‌Beneficial effects: 1. The present invention has higher integrity and structural strength; the one-time molding process directly makes the composite material into the shape of the final product in a continuous process, and the bonding between the materials is tighter. The one-time molded composite material structural parts can better withstand various stresses and pressures, and the integrity of the entire structure is better. There is no performance difference caused by the difference in molding process between different parts, so that the performance of each part of the product during use is more uniform and stable.

[0015] 2. The present invention has higher production efficiency: The one-shot molding process of the present invention does not require additional steps such as secondary processing or assembly, which reduces the production process and operation links and greatly shortens the production cycle. For the large-scale production of drone ventral fins or other similar composite foam sandwich structure products, it significantly improves production efficiency and reduces costs; it also avoids the time consumption of waiting for materials to solidify and reheating during the secondary molding process, making the production process more continuous and efficient.

[0016] 3. The dimensional accuracy of the present invention is easier to ensure: in the one-time molding process, the deformation and shrinkage of the material can be controlled under a unified process condition. Since multiple assembly and adjustment are not required, the dimensional accuracy of the product is guaranteed, especially for some parts with complex shapes and high dimensional accuracy requirements, such as the ventral fin structure of a drone with special curved surfaces or high-precision matching requirements. One-time molding can better meet the design requirements and reduce product performance degradation or assembly problems caused by dimensional deviation.

[0017] 4. The present invention has strong designability: the foam density can be controlled by adjusting the quality of the filling foam, thereby meeting the diverse requirements of composite materials for the performance of sandwich products and facilitating the later weight reduction design. Based on the characteristics of epoxy foam foaming along with the cavity during the foaming process, the preparation of composite products with complex structures has greater tolerance, and sandwich products with gradient structures can be designed according to the stress conditions of the product, so that the product can have different performance characteristics in different parts. For example, higher density foaming materials or increased number of prepreg layers are used in parts subject to greater stress, while low-density foaming materials are used in parts subject to less stress to reduce weight, thereby enhancing the designability of the product and better meeting the performance requirements in different application scenarios.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the lower mold of the present invention; Figure 3 This is a schematic diagram of the upper mold of the present invention; Figure 4 It is a schematic diagram of mold closing of the present invention.

[0021] In the figure: 1. upper mold; 2. lower mold; 3. bottom plate mold. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example: according to Figure 1-Figure 4 A one-step molding method for producing a foam sandwich structure product from a composite material includes the following steps: Step 1: mold pretreatment; the composite product mold includes an upper mold 1, a lower mold 2 and a base mold 3. The composite product mold is processed before production to ensure that the mold surface is smooth and heated, and a release agent is evenly coated on the mold surface.

[0024] Step 2: Lay the carbon fiber prepreg on the upper mold 1; Figure 3 As shown, two layers of carbon fiber prepreg are laid on the upper mold 1 of the mold.

[0025] Step 3: Lay the carbon fiber prepreg on the lower mold 2; Figure 2 As shown, two layers of carbon fiber prepreg are laid on the lower mold 2 of the mold, and a circle of inward turning is reserved around the carbon fiber prepreg laid on the lower mold 2 to facilitate wrapping the material during the subsequent mold closing operation and ensure the integrity of the material in the mold cavity; at the same time, a reinforcement layer is pasted on the flange of the lower mold, and the reinforcement layer is pasted on the first layer and the second layer of material, which significantly improves the strength of the flange part and enhances the stability of the overall structure. The reinforcement layer is pasted on the flange of the lower mold, and the reinforcement layer is pasted on the first layer and the second layer of material. Step 4: Pave the bottom plate mold 3 with carbon fiber prepreg; use the same brand of carbon fiber prepreg leftovers to pave the bottom plate mold 3 of the mold, and the laid carbon fiber prepreg is flush with the outer edge of the bottom plate mold 3; ensure that the material distribution of the bottom plate mold 3 is even and compatible with the entire mold structure.

[0026] Step 5: Cold pre-pumping; Place the upper mold 1, lower mold 2 and bottom plate mold 3 after laying the carbon fiber prepreg in a vacuum package for cold pre-pumping in the workshop; Cold pre-pumping can remove the gaps between the prepreg layers and the bubbles generated by laying, and remove air and volatiles, effectively remove the air between the materials, improve the tightness of the materials, improve the quality and performance of the products, and reduce the occurrence of internal defects.

[0027] Step 6: Laying the foaming material; evenly lay a layer of epoxy foam in the lower mold 2; when laying, the edge area and each corner must be affixed to the foaming material, and more foaming material should be affixed to the thicker area of ​​the composite product to adapt to the structural strength and lightweight requirements of different parts; make full use of the self-adhesive characteristics of epoxy foam, just fix it in the mold without compacting, so as to ensure that the foaming material can foam evenly and fill the interlayer space in the subsequent molding process.

[0028] Step 7: Auxiliary paving of the upper mold 1; a strip of epoxy foam is laid at the corner where the upper mold 1 contacts the flange, and no laying is done at the flange; a strip of material is laid at the corner where the upper mold 1 contacts the flange to enhance the buffering and connection performance of the corner, and no laying is done at the flange according to the process design to avoid affecting the mold closing accuracy and subsequent processing operations; this special paving method helps to ensure the connection tightness and structural integrity between the upper and lower molds during mold closing, while avoiding unnecessary impact on the flange.

[0029] Step 8: mold closing; Figure 4 As shown, the bottom plate mold 3 is combined with the upper mold 1 and the lower mold 2, and screwed together. Step nine: hot pressing; preheat the press to 135℃~140℃ in advance. The press can be preheated to 130℃, 136℃, 138℃, 145℃ or 146℃ according to the actual situation on site; then the assembled mold is smoothly sent into the press and pressurized to 10MPa. After the mold is heated to 135℃~140℃, keep it for 30min to allow the prepreg to fully cure, the foaming material to complete expansion and foaming and tightly integrate with the prepreg to form an integrated sandwich structure, and then start to cool down. No pressure is released during the entire cooling process to maintain the shape and structural stability of the product. Step 10: Post-processing steps; wait for the mold to cool down to below 40°C, safely release the pressure and remove the mold. First, accurately drill holes at the flange to meet the subsequent assembly and connection requirements. Then open the mold smoothly, carefully take out qualified products and send them to the fitter in time for fine repair to ensure that the product edges are smooth and the dimensions are accurate to meet the design requirements.

[0030] Furthermore, in the step one, the mold surface is evenly coated with a release agent three times, with an interval of 10 to 15 minutes between each coat. The release agent needs to be completely dry before being coated again. Finally, the mold is heated to 40 to 50°C. The press can be preheated to 36°C, 38°C, 48°C, 51°C or 55°C in advance according to the actual situation on site, so as to create a good demoulding foundation and process temperature environment for subsequent material paving.

[0031] The stacking method of carbon fiber prepreg has an important influence on product performance; the prepreg stacking angle refers to the angle between the prepreg layer material and the mold substrate in the vertical direction; the prepreg stacking angle can affect the density, strength, stiffness and other properties of the composite material, so it is very important to choose a suitable stacking angle. Among them, the 45° stacking method can achieve a balance in strength, stiffness and toughness, and the 0° stacking method, which is parallel to the substrate, can achieve higher strength and stiffness.

[0032] Furthermore, in the steps 2 and 3, preferably, the first layer of carbon fiber prepreg is pasted with 45° carbon fiber prepreg, the second layer of carbon fiber prepreg is pasted with 0° carbon fiber prepreg, and there are no specific requirements for the angles in other places. The paving method of the prepreg of the present invention helps to provide suitable mechanical properties in different directions. The first layer of carbon fiber prepreg is pasted with 45° carbon fiber prepreg, which can effectively adjust the internal stress distribution direction of the material and optimize the force characteristics; the second layer of carbon fiber prepreg is pasted with 0° carbon fiber prepreg to strengthen the axial mechanical performance support; there are no specific requirements for the angles in other places, but it is also necessary to ensure that the paving is flat and tight, without wrinkles, bubbles and other defects.

[0033] Furthermore, in the step three, the width of the inward flange reserved around the carbon fiber prepreg laid on the lower mold 2 is 9 to 10 mm.

[0034] Furthermore, the surface density of the carbon fiber prepreg used in step 2, step 3 and step 4 is 330g±10g, wherein the surface density of the carbon fiber is 200±10g, and the resin content is 40%±2, so as to ensure the consistency and stability of the material performance.

[0035] Furthermore, in step five, preferably, the cold pre-pumping time is 35 to 40 minutes.

[0036] Furthermore, in the step 5, a circle of flange around the lower mold 2 is isolated from the lower mold 2 by an isolation fabric before pre-drawing to prevent mold sticking in subsequent process.

[0037] Furthermore, the foam used in step six and step seven is an epoxy resin system, and the thermal natural expansion ratio is 50 times. According to the actual situation on site, heating at 110°C, 130°C, 145°C or 155°C is possible; the epoxy foam filling density is 60-100kg / m 3 , according to the actual working conditions, 65kg / m 3 or 80kg / m 3 Both are isotropic and can provide balanced mechanical support in different directions; the foam density can be controlled by adjusting the quality of the filled epoxy foam to meet the diverse requirements of composite materials for the performance of sandwich products, and sandwich products with gradient structures can be designed to achieve different performance characteristics in different parts of the product.

[0038] ‌Furthermore, in step eight, when closing the mold, the flange around the lower mold 2 is cleverly folded inward along the edge of the mold to ensure that the material is completely wrapped in the mold cavity when closing the mold, and the flange of the lower mold 2 tightly wraps the foaming material to prevent the material from overflowing and shifting; after the upper and lower molds are closed, the flange of the lower mold 2 is appropriately lifted upward to make the carbon fiber prepreg of the upper and lower molds fit closely to form a stable overall structure, and then the bottom plate is firmly combined with the upper and lower molds with screws to ensure the mold assembly accuracy and structural stability.‌

[0039] A mold used in a one-time molding method for producing a foam sandwich structure product from a composite material, the mold comprising an upper mold 1, a lower mold 2 and a bottom plate mold 3. After the molds are respectively paved with carbon fiber prepreg and foamed foam is placed, the bottom plate mold 3 is combined with the upper mold 1 and the lower mold 2 and fixed with screws to ensure that the product is molded in one time.

[0040] In the actual production process, the process parameters can be adjusted according to different product requirements. For example, if higher structural strength is required, the number of prepreg layers can be appropriately increased or a higher strength prepreg grade can be selected; if the weight of the product needs to be adjusted, the foam density can be controlled by changing the amount of epoxy foam laid, thereby achieving a weight reduction or weight gain design; if the shape of the product is more special or complex, the laying angle of the prepreg and the laying area of ​​the foam material can be optimized according to its specific structure to ensure that all parts can obtain a good molding effect in the one-time molding process.

[0041] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0042] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0043] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0044] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A one-step molding method for producing a foam sandwich structure product from a composite material, characterized in that: The following steps are involved: Step 1: pretreatment of the mold; the composite product mold comprises an upper mold (1), a lower mold (2) and a base plate mold (3). Before production, the composite product mold is processed to ensure that the mold surface is smooth and heated, and a release agent is evenly coated on the mold surface; Step 2: laying carbon fiber prepreg on the upper mold (1); laying two layers of carbon fiber prepreg on the upper mold (1) of the mold respectively; Step 3: The lower mold (2) is paved with carbon fiber prepreg; two layers of carbon fiber prepreg are paved on the lower mold (2) of the mold respectively, a circle of inward turning edges is reserved around the carbon fiber prepreg paved on the lower mold (2), a reinforcement layer is pasted on the flange of the lower mold, and the reinforcement layer is pasted on the first layer of material and the second layer of material; Step 4: paving the bottom plate mold (3) with carbon fiber prepreg; paving the bottom plate mold (3) of the mold with the remaining carbon fiber prepreg of the same brand, so that the paved carbon fiber prepreg is flush with the outer edge of the bottom plate mold (3); Step 5: cold pre-extraction; placing the upper mold (1), the lower mold (2) and the bottom plate mold (3) after the carbon fiber prepreg is laid in a vacuum package for cold pre-extraction in the workshop; Step 6: paving the foaming material; evenly paving a layer of epoxy foam in the lower mold (2); when paving the foaming foam, the edge area and each corner must be affixed with the foaming material, and more foaming material is affixed to the thicker area of ​​the composite product; Step 7: Assisting paving of the upper mold (1); laying a strip of epoxy foam at the corner where the upper mold (1) contacts the flange, but not laying at the flange; Step 8: Mold closing: Combine the bottom plate mold (3) with the upper mold (1) and the lower mold (2), and fix them with screws; Step 9: Hot pressing: preheat the press to 135℃~140℃, put the mold into the press after mold closing, and pressurize it to 10MPa. After the mold is heated to 135℃~140℃, keep it for 30min and then start cooling. Do not release the pressure during the whole cooling process. Step 10: Post-processing steps; wait for the mold to cool down to below 40°C, release the pressure and remove the mold, first drill a hole at the flange, then open the mold; take out the qualified products and send them to the fitter for repair.

2. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: In the step 1, the mold surface is coated with a release agent three times, with an interval of 10 to 15 minutes between each coat, and finally the mold is heated at a temperature of 40 to 50°C.

3. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: In the steps 2 and 3, the first layer of carbon fiber prepreg is pasted with 45° carbon fiber prepreg, and the second layer of carbon fiber prepreg is pasted with 0° carbon fiber prepreg. There are no specific requirements for the angles in other places.

4. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: In the step three, the width of the inward flange reserved around the carbon fiber prepreg laid on the lower mold (2) is 9 to 10 mm.

5. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: The surface density of the carbon fiber prepreg used in step 2, step 3 and step 4 is 330g±10g, wherein the surface density of the carbon fiber is 200±10g, and the resin content is 40%±2.

6. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: In the step 5, the cold pre-pumping time is 35 to 40 minutes.

7. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: In the step five, before pre-drawing, a circle of flange around the lower mold (2) is isolated from the lower mold (2) by an isolation fabric.

8. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: The foam used in step 6 and step 7 is an epoxy resin system, with a thermal natural expansion ratio of 50 times, a starting temperature of 100°C to 150°C, and an epoxy foam filling density of 60 to 100 kg / m 3 , and isotropic.

9. A one-step molding method for producing a foam sandwich structure product from a composite material as claimed in claim 1, characterized in that: In the step eight, when closing the mold, the flange around the lower mold (2) is first turned inward along the edge of the mold to ensure that the material is completely in the mold cavity when closing the mold, and the flange can wrap the foaming material; after closing the mold, the flange of the lower mold (2) is lifted upward to ensure that the carbon fiber prepreg of the upper mold (1) and the lower mold (2) are attached to each other.

10. A mold used in a one-step molding method for producing a foam sandwich structure product from a composite material as claimed in any one of claims 1 to 9, characterized in that: The mould comprises an upper mould (1), a lower mould (2) and a bottom plate mould (3). After the moulds are paved with carbon fiber prepreg and foamed foam is placed therein, the bottom plate mould (3) is combined with the upper mould (1) and the lower mould (2) and fixed with screws to ensure that the product is formed in one step.

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