Air bag auxiliary fuselage integral forming method

Abstract

The invention discloses an air bag auxiliary fuselage integral forming method which comprises the following steps: a) designing and manufacturing a mold according to the boundary dimension of a fuselage, unfolding the size and shape of a product by using software, and cutting a carbon fiber prepreg; b) paving prepreg on the machine body lower mold and the machine body upper mold according to the shape, and vacuumizing and pre-compacting; c) after paving, paving an auxiliary material, closing the mold, positioning through a positioning pin and fastening through a bolt; d) after the upper die and the lower die are closed, arranging overlapping edges, placing the air bags, connecting the air bags through vacuum bags, and vacuumizing and pre-compacting again; e) removing the vacuum bag, locking the mold, inflating the air bag and checking the air pressure, and adjusting the air pressure and curing after the air bag is correct; and f) demolding and finishing to obtain a product body. Through uniform expansion of the airframe air bag in the curing process, the carbon fiber prepreg is tightly attached to the shape of the mold, defects such as gaps and bubbles are effectively avoided, and therefore the forming precision of a product is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of equipment manufacturing, and in particular to an airbag-assisted fuselage integral molding method. Background Art

[0002] In the fields of aviation, aerospace, automobile and high-end equipment manufacturing, the manufacture of fuselage or similar cylindrical semi-enclosed structures often requires high performance, light weight and low cost. Traditionally, such structures are mostly manufactured using a split-half molding process, that is, the composite material is first made into two halves, and then combined into a complete cylindrical structure through fasteners or other connection methods. However, this process has several significant limitations: The performance of composite materials is not fully utilized: the half-molding process makes it difficult to ensure the optimal distribution and orientation of the composite materials in the overall structure, thus limiting the full utilization of their mechanical properties and durability.

[0003] High process cost: Half-molding requires additional mold design and manufacturing, as well as subsequent assembly and fastening processes, which increase the overall manufacturing cost.

[0004] Increased weight: The use of fasteners and other connecting parts not only increases the complexity of the structure, but also leads to unnecessary weight increase, which is a significant disadvantage for modern vehicles that pursue lightweight.

[0005] Difficulty in removing the core mold: When the outer mold and the core mold are combined for laying, the removal of the core mold is often a time-consuming and complicated process, affecting production efficiency and cost-effectiveness.

[0006] High customization costs: If airbags and air bags are used as core molds, although a certain molding effect can be achieved, because they require customized design, they are often accompanied by high manufacturing costs. Self-made products such as silicone airbags will also add additional process steps and costs.

[0007] In summary, the existing half-molding process and its related technical solutions have many deficiencies in the manufacture of composite cylindrical semi-enclosed structures, and a new process is urgently needed to overcome the above defects, maximize the performance of composite materials, reduce costs, reduce weight and improve production efficiency. The fuselage composite one-piece molding process of the present invention is an innovative solution proposed to meet this demand. Summary of the invention

[0008] The purpose of the present invention is to solve the above technical problems, thereby providing an airbag-assisted fuselage integrated molding method; In order to solve the above technical problems, the present invention provides the following technical solutions: The present invention provides an airbag-assisted fuselage integral forming method. The following steps are involved: a) Based on the fuselage dimensions, the mold is precisely designed and manufactured using Fibersim software to develop the product size and shape, ensuring that the cut prepreg completely matches the fuselage shape; b) Precisely lay the prepreg on the fuselage lower mold and the fuselage upper mold according to the shape of the fuselage, and use a vacuum pre-compaction process to ensure that the vacuum degree is above 0.085Mpa to remove the air between the materials and ensure the close fit of the prepreg; c) After the paving is completed, auxiliary materials are laid on the prepreg, and then the upper mold of the fuselage is turned over, accurately positioned with the lower mold of the fuselage through positioning pins, and fastened with bolts to ensure the stability and accuracy of the mold during the mold closing process; d) After the upper and lower molds are closed, the overlapping edges are carefully arranged to ensure that they fit tightly. Then, the fuselage airbag is placed from the fuselage round cover mold, and the vacuum bag made in the upper mold is connected to the fuselage airbag through sealant. Vacuuming and pre-compacting are performed again to ensure that the fuselage airbag fits the fuselage shape perfectly. e) Remove the vacuum bag made by the upper mold, lock the fuselage front cover mold and the fuselage rear cover mold, close the fuselage round cover mold, inflate the air nozzle of the fuselage air bag, and check the air pressure gauge. Inflate to 0.4Mpa for the first time, keep the air pressure unchanged after 5 minutes, and after confirming that it is correct, adjust the air pressure to 0.6Mpa, then put the mold into the curing oven, and heat it to 125℃ for curing; f) After curing is completed, demoulding is performed and the product body is trimmed to obtain the final airbag-assisted body one-piece molding product.

[0009] Optionally, the Fibersim software is used to accurately develop product size and shape to ensure a high degree of matching between the cut carbon fiber prepreg and the fuselage shape.

[0010] Optionally, the vacuum degree of the vacuum pre-compacting process is controlled at above 0.085 MPa to ensure close fit between the prepreg and the auxiliary materials and to exclude air between the materials.

[0011] Optionally, the fuselage mold includes a fuselage lower mold, a fuselage upper mold, a fuselage front cover mold, a fuselage rear cover mold and a fuselage round cover mold, and in addition to the single-side opening, the fuselage upper mold is also provided with two openings at both ends in the middle, which is convenient for installing other equipment after the fuselage is formed, and convenient for arranging and adjusting the position of the fuselage air bag during the inflation process of the fuselage air bag.

[0012] Optionally, the inflation step of the fuselage airbag includes initially inflating to 0.4Mpa, maintaining it for 5 minutes, and checking whether the air pressure remains unchanged, and then adjusting the air pressure to 0.6Mpa after confirmation, so as to ensure the stability of the fuselage airbag during the curing process and the performance of the final product.

[0013] Optionally, the curing step includes heating the mold to 125° C. for curing to ensure sufficient curing of the carbon fiber prepreg and the fuselage airbag and the final performance of the product.

[0014] Optionally, the final product fuselage is obtained through demoulding and trimming steps, and has the characteristics of high precision, high strength and high performance, and is suitable for various fuselage structures requiring high precision and strength.

[0015] In summary, the present invention has the following beneficial effects: The present invention makes the carbon fiber prepreg closely fit the mold shape through the uniform expansion of the fuselage airbag during the curing process, effectively avoiding the generation of defects such as gaps and bubbles, thereby significantly improving the molding accuracy of the product. The uniform pressure provided by the fuselage airbag helps to reduce the thermal stress and deformation of the product during the curing process, so that the final product has better dimensional stability and shape retention. The auxiliary effect of the fuselage airbag makes the product surface smoother and flatter, reducing surface defects that may occur in traditional processes, such as wrinkles and dents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the fuselage forming product and the mold structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the body airbag of the present invention that is attached to the product by vacuuming.

[0018] Figure 3 It is a schematic diagram after the mold filling of the present invention is completed.

[0019] Explanation of the accompanying drawings: 1-fuselage lower mold, 2-fuselage upper mold, 3-fuselage rear cover mold, 4-fuselage front cover mold, 5-fuselage, 6-fuselage air bag, 7-air nozzle, 8-fuselage round cover mold. DETAILED DESCRIPTION

[0020] 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 new embodiments of the system. 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.

[0021] Example: like Figure 1-Figure 3 As shown, the present invention provides an airbag-assisted fuselage integral forming method, The following steps are involved: a) Based on the fuselage dimensions, the mold is precisely designed and manufactured using Fibersim software to develop the product size and shape, ensuring that the cut prepreg completely matches the fuselage shape; b) Precisely lay the prepreg on the fuselage lower mold 1 and the fuselage upper mold 2 according to the shape of the fuselage, and use a vacuum pre-compaction process to ensure that the vacuum degree is above 0.085Mpa to remove the air between the materials and ensure the close fit of the prepreg; c) After the paving is completed, auxiliary materials are laid on the prepreg, and then the upper mold 2 of the fuselage is turned over, accurately positioned with the lower mold 1 of the fuselage through positioning pins, and fastened with bolts to ensure the stability and accuracy of the mold during the mold closing process; d) After the upper and lower molds are closed, the overlapping edges are carefully arranged to ensure that the overlapping edges are tightly fitted, and then the fuselage air bag 6 is placed from the fuselage round cover mold 8, and the vacuum bag made in the upper mold is connected to the fuselage air bag 6 through the sealant, and vacuum pre-compacted again to ensure that the fuselage air bag 6 and the fuselage shape fit perfectly; e) Remove the vacuum bag made by the upper mold, lock the fuselage front cover mold 4 and the fuselage rear cover mold 3, close the fuselage round cover mold 8, inflate the air nozzle 7 of the fuselage air bag 6, and check the air pressure gauge. Initially inflate to 0.4Mpa, keep the air pressure unchanged for 5 minutes, and after confirmation, adjust the air pressure to 0.6Mpa, then put the mold into the curing oven, and heat it to 125℃ for curing; f) After curing is completed, demoulding operation is performed and the product fuselage 5 is trimmed to obtain the final airbag-assisted fuselage integrated molding product.

[0022] The above steps include the following instructions: First, the outer dimensions of the fuselage 5 are accurately measured to obtain detailed three-dimensional data, and Fibersim software is used to perform accurate three-dimensional mold design based on the outer dimension data of the fuselage 5. This software can ensure the accuracy and precision of the mold design. According to the design data of the Fibersim software, mold components such as the fuselage lower mold 1 and the fuselage upper mold 2 are manufactured, and at the same time, the manufacturing accuracy and quality of the mold are ensured.

[0023] In the Fibersim software, expand the size and shape of the fuselage 5 product to ensure that the cut carbon fiber prepreg completely matches the shape of the fuselage 5. This step is the key to ensure that the subsequent prepreg can fit the shape of the fuselage 5 tightly.

[0024] On the fuselage lower mold 1 and the fuselage upper mold 2, the prepregs cut and paved are precisely laid according to the shape of the fuselage 5. This step requires ensuring that the laying position, direction and quantity of the prepregs are accurate.

[0025] The prepregs are compacted using a vacuum pre-compacting process to ensure that the vacuum degree is above 0.085 MPa, so as to remove the air between the materials and ensure that the prepregs fit tightly. This step is the key to ensure that the prepregs can maintain a tight fit during the subsequent molding process.

[0026] Auxiliary materials such as release cloth, breathable felt, etc. are laid on the prepreg. These auxiliary materials help to maintain the shape and position of the prepreg during the molding process, and also facilitate demoulding and subsequent processing.

[0027] The upper mold 2 of the fuselage is turned over, and it is precisely positioned with the lower mold 1 of the fuselage through positioning pins and fastened with bolts to ensure the stability and accuracy of the mold during the mold closing process. This step is the key to ensure that the mold can remain tightly closed during the subsequent molding process to avoid movement or deformation of the prepreg.

[0028] After the upper and lower molds are closed, the overlapping edges are carefully arranged to ensure that the overlapping edges are tightly fitted. This step is the key to ensure that the fuselage airbag 6 can expand evenly during the subsequent inflation process and avoid the generation of bubbles or cavities.

[0029] The fuselage airbag 6 is placed into the mold from the fuselage dome mold 8. The shape and size of the fuselage airbag 6 should match the shape of the fuselage 5 to ensure that it can expand evenly and fit the shape of the fuselage 5 closely during the inflation process.

[0030] The vacuum bag made in the upper mold is connected to the fuselage air bag 6 through a sealant, and vacuum pre-compacted again to ensure that the fuselage air bag 6 and the fuselage 5 fit perfectly in shape, while further eliminating the air between the materials.

[0031] Remove the vacuum bag made by the upper mold, lock the fuselage front cover mold 4 and the fuselage rear cover mold 3, close the fuselage round cover mold 8, inflate the air nozzle 7 of the fuselage air bag 6, and check the air pressure gauge. Inflate to 0.4Mpa for the first time and keep the air pressure unchanged after 5 minutes. This step is the key to ensure that the fuselage air bag 6 can expand evenly and fit the shape of the fuselage 5 tightly.

[0032] After confirmation, adjust the air pressure to 0.6Mpa, then put the mold into the curing oven and heat it to 125°C for curing. During the curing process, the pressure environment provided by the fuselage airbag 6 helps the composite material prepreg to fit tightly and cure.

[0033] After curing is completed, demoulding operation is performed, the mold is opened, and the molded fuselage 5 structure is taken out. This step requires careful operation to avoid damaging the molded product.

[0034] The product body 5 is subjected to finishing treatments, such as grinding and trimming, to ensure that the product surface is smooth and defect-free to meet the final product requirements. This step is the key to ensuring the product appearance quality and subsequent performance.

[0035] In summary, the airbag-assisted fuselage integrated molding method provided by the present invention realizes the efficient, precise and high-quality production of the composite fuselage 5 through key steps such as precise design and manufacturing of molds, prepreg laying and pre-compacting, auxiliary material laying and mold closing, placement and re-pre-compacting of the fuselage airbag 6, inflation and curing treatment, demolding and trimming. This method not only improves the precision and quality of the product, but also reduces the process cost and material waste, and has significant technical innovation and practical application value.

[0036] The Fibersim software is used to accurately develop the product size and shape, ensuring that the cut carbon fiber prepreg is highly compatible with the shape of the fuselage 5.

[0037] Since Fibersim can accurately unfold the size and shape of prepreg, it can minimize material waste, which not only helps to reduce costs, but also helps to improve production efficiency and environmental performance. The precisely cut prepreg can fit the shape of the fuselage 5 closely, reducing gaps and defects in the molding process. This helps to improve the overall quality and mechanical properties of the product, enabling it to meet strict performance requirements. Through automated layer unfolding and optimized design, Fibersim can significantly shorten the production cycle of composite parts. Engineers can complete design work faster and pass accurate design data to the manufacturing department, thereby accelerating product development and market launch.

[0038] In summary, Fibersim software ensures a high degree of matching between the cut carbon fiber prepreg and the shape of the fuselage 5 by integrating 3D CAD system, automatic ply unfolding and optimized ply design. This feature is of great significance in improving product quality, reducing costs and shortening production cycles.

[0039] The vacuum degree of the vacuum pre-compacting process is controlled at above 0.085 MPa to ensure close fit between the prepreg and the auxiliary materials and to exclude air between the materials.

[0040] When the vacuum degree reaches above 0.085Mpa, sufficient negative pressure can be generated to make the prepreg and auxiliary materials subject to uniform pressure in the mold, thereby achieving a close fit. This close fit helps to reduce gaps and defects in the molding process and improve the overall quality of the product.

[0041] High vacuum can effectively remove the air between the prepreg and auxiliary materials. The presence of air will affect the curing effect and mechanical properties of the composite material, so removing air is the key to ensuring product quality.

[0042] Tight fit and air exclusion help the composite material to be heated and compressed more evenly during the curing process, thereby improving the curing effect and giving the product better mechanical properties and stability.

[0043] In summary, controlling the vacuum degree above 0.085Mpa in the vacuum pre-compaction process is a key measure to ensure the close fit of prepreg and auxiliary materials and to exclude air between materials. By taking a series of effective control measures and application practices, the quality of products and production efficiency can be significantly improved.

[0044] The fuselage mold includes a fuselage lower mold 1, a fuselage upper mold 2, a fuselage front cover mold 4, a fuselage rear cover mold 3 and a fuselage round cover mold 8. In addition to the single-side opening, the fuselage upper mold 2 is also provided with two openings at both ends in the middle, which is convenient for installing other equipment after the fuselage 5 is formed, and convenient for arranging and adjusting the position of the fuselage air bag 6 during the inflation process of the fuselage air bag 6.

[0045] The fuselage lower mold 1 is the basic part of the mold, used to support and position the prepreg and auxiliary materials. Its shape and size match the lower part of the fuselage 5 to ensure the accuracy and stability of the lower part during the molding process.

[0046] The upper mold 2 of the fuselage cooperates with the lower mold 1 of the fuselage to form a complete mold cavity. In addition to the single-side opening for mold closing and demolding, there are two openings at both ends in the middle. These openings are convenient for installing other equipment after the fuselage 5 is formed, such as electronic equipment, pipelines, etc.

[0047] During the inflation process of the fuselage airbag 6 , the two openings are also convenient for arranging and adjusting the position of the fuselage airbag 6 , ensuring that the fuselage airbag 6 can expand evenly and closely fit the shape of the fuselage 5 .

[0048] The fuselage front cover mold 4 and the fuselage rear cover mold 3 are used to cover the front and rear of the fuselage 5 respectively, and together with the fuselage lower mold 1 and the fuselage upper mold 2 form a complete mold cavity. Their shapes and sizes match the corresponding parts of the fuselage 5 to ensure the integrity and accuracy of the fuselage 5 during the molding process.

[0049] Fuselage round cover mold 8: used to cover the circular part of the fuselage 5, and together with the fuselage lower mold 1, the fuselage upper mold 2, the fuselage front cover mold 4 and the fuselage rear cover mold 3 form a complete mold cavity, whose shape and size match the top or circular part of the fuselage 5 to ensure the accuracy and stability of this part during the molding process.

[0050] The opening design at both ends of the middle of the fuselage upper mold 2 makes it easy to install other equipment, such as electronic equipment, sensors, pipelines, etc. after the fuselage 5 is formed. This design improves the flexibility and convenience of production.

[0051] During the inflation process of the fuselage air bag 6, the two openings also facilitate the arrangement and adjustment of the position of the fuselage air bag 6. Through the two openings, the operator can easily access the fuselage air bag 6 and ensure that it can expand evenly and fit the shape of the fuselage 5 closely during the inflation process, which helps to reduce the generation of defects such as bubbles and cavities, and improve the quality and performance of the product. This special design makes the fuselage 5 molding and subsequent equipment installation process more efficient. The operator can install and adjust the equipment without moving the entire mold, thereby saving time and labor costs.

[0052] The inflation step of the fuselage airbag 6 includes initially inflating to 0.4Mpa, and checking whether the air pressure remains unchanged after maintaining for 5 minutes, and then adjusting the air pressure to 0.6Mpa after confirmation to ensure the stability of the fuselage airbag 6 during the curing process and the performance of the final product.

[0053] 1. Initial inflation to 0.4Mpa Purpose: The main purpose of the initial inflation is to initially expand the fuselage airbag 6 and initially fit the shape of the fuselage 5. By setting a relatively low initial air pressure of 0.4Mpa, problems such as rupture of the fuselage airbag 6 or deformation of the prepreg due to excessive air pressure can be avoided.

[0054] Operation process: Place the fuselage air bag 6 into the mold and ensure that it is in the correct position. Connect the inflation equipment such as an air compressor, air pump, etc. to the air nozzle 7 of the fuselage air bag 6, turn on the inflation equipment, start to inflate the fuselage air bag 6, monitor the air pressure gauge, and stop inflation when the air pressure reaches 0.4Mpa.

[0055] 2. Hold for 5 minutes and check the air pressure Purpose: Maintaining for a period of time, such as 5 minutes, and checking whether the air pressure remains unchanged is to verify the sealing and stability of the fuselage airbag 6. If the air pressure drops significantly during the holding period, it means that the fuselage airbag 6 may have a leakage problem and needs to be dealt with in time.

[0056] Operation process: After the initial inflation to 0.4Mpa, start timing immediately, keep the inflation device closed, and allow the fuselage air bag 6 to naturally maintain air pressure in the mold. After 5 minutes, check the pressure gauge again to confirm whether the air pressure is still maintained at around 0.4Mpa. If the air pressure drops significantly, it is necessary to check whether there is any leakage in the connection parts such as the air nozzle 7 and sealant of the fuselage air bag 6, and repair them in time.

[0057] 3. Adjust the air pressure to 0.6Mpa Purpose: After confirming that there are no problems with the sealing and stability of the fuselage airbag 6, the air pressure is adjusted to a higher level of 0.6Mpa to ensure that the fuselage airbag 6 can provide a sufficient pressure environment during the curing process, so that the prepreg fits the mold shape closely and achieves the desired curing effect.

[0058] Operation process: If the air pressure after the initial inflation remains correct, continue to open the inflation device and slowly increase the air pressure to 0.6Mpa. Pay attention to monitoring the changes in the pressure gauge. When the air pressure reaches 0.6Mpa, stop inflating and check the sealing and stability of the fuselage airbag 6 again.

[0059] IV. Precautions Inflation speed: During the inflation process, the inflation speed should be controlled not to be too fast to avoid the fuselage airbag 6 from rupturing due to a sharp increase in air pressure.

[0060] Air pressure monitoring: The changes in the air pressure gauge should be continuously monitored during the entire inflation process to ensure that the air pressure fluctuates within the predetermined range.

[0061] Safety inspection: Before inflation, the inflation equipment and molds should be thoroughly inspected to ensure that all connections are firm and reliable without leakage risks.

[0062] Curing treatment: After the inflation is completed, the mold should be placed in the curing oven for curing treatment in time to ensure that the prepreg can be fully cured and achieve the required mechanical properties.

[0063] In summary, the inflation step of the fuselage airbag 6 is one of the key links in the airbag-assisted fuselage integrated molding method. By strictly controlling the inflation pressure and operating steps, the stability of the fuselage airbag 6 during the curing process and the performance of the final product can be ensured.

[0064] The curing step includes heating the mold to 125° C. for curing to ensure sufficient curing of the carbon fiber prepreg and the fuselage airbag 6 and the final performance of the product.

[0065] Heating the mold to 125°C for curing is determined based on the characteristics and curing requirements of the carbon fiber prepreg material. The carbon fiber prepreg usually contains a resin matrix and a carbon fiber reinforcement material, and the curing temperature of the resin matrix is ​​a key factor affecting its curing degree and performance. The curing temperature of 125°C can ensure that the resin matrix undergoes a chemical reaction at an appropriate temperature to complete the curing process, while avoiding material degradation or performance degradation caused by excessive temperature.

[0066] At a temperature of 125°C, the cross-linking reaction in the resin matrix is ​​fully carried out to form a stable three-dimensional network structure. This process causes the resin matrix to transform from liquid to solid, giving the composite material excellent mechanical properties and thermal stability.

[0067] During the curing process, the fuselage airbag 6 maintains a certain air pressure, which helps the carbon fiber prepreg to fit the mold shape closely and prevent the generation of gaps or bubbles. At the same time, the existence of the fuselage airbag 6 can also transfer heat evenly to a certain extent and promote the uniform curing of the resin matrix.

[0068] Through sufficient curing treatment, the mechanical properties of carbon fiber composite materials such as strength, modulus, and thermal stability are significantly improved. In addition, the curing process also helps to reduce the residual stress and deformation of the product and improve the dimensional stability and surface quality of the product.

[0069] Heating the mold to 125°C for curing is an important step in the airbag-assisted fuselage integrated molding process. By strictly controlling the curing temperature, insulation time, and fuselage airbag 6 management and other operating points, the carbon fiber prepreg and fuselage airbag 6 can be fully cured, thereby ensuring the final performance and quality of the product.

[0070] The final product fuselage 5 is obtained through demoulding and finishing steps, and has the characteristics of high precision, high strength and high performance, and is suitable for various fuselage 5 structures requiring high precision and strength.

[0071] The airbag-assisted integrated fuselage molding method involved in the present invention has the core of utilizing the fuselage airbag 6 to form a certain pressure environment inside the mold to assist the composite material prepreg to be tightly fitted and cured in the mold, thereby directly obtaining a complete cylindrical semi-enclosed fuselage structure. This method avoids the problems of composite material performance loss, process cost increase, weight increase, and difficulty in core mold disassembly in the traditional half-molding process.

[0072] The present invention includes the following steps during use: Mould design and manufacturing According to the external dimensions of the fuselage 5, the mold shape is accurately designed using special software such as Fibersim, and the mold is manufactured, including the fuselage lower mold 1, the fuselage upper mold 2, the fuselage front cover mold 4, the fuselage rear cover mold 3, and the fuselage round cover mold 8. In particular, in addition to the single-sided opening, the fuselage upper mold 2 is also provided with two openings at both ends in the middle to facilitate subsequent operations.

[0073] Prepreg cutting and laying Use Fibersim software to expand the product size and shape, ensure that the cut carbon fiber prepreg completely matches the shape of the fuselage 5, and accurately lay the prepreg on the fuselage lower mold 1 and the fuselage upper mold 2 according to the shape of the fuselage.

[0074] Vacuum pre-compacting After laying auxiliary materials on the prepreg, vacuum pre-compaction is performed. This step is to remove the air between the materials, ensure the close fit between the prepreg and the mold, and improve the molding quality. The vacuum degree must be controlled above 0.085Mpa.

[0075] Mould closing and positioning The upper mold 2 of the fuselage is turned over, and accurately positioned with the lower mold 1 of the fuselage through the positioning pins, and fastened with bolts. To ensure the stability and accuracy of the mold during the mold closing process, the fuselage air bag 6 is placed and vacuumed again, and the fuselage air bag 6 is placed into the mold from the fuselage round cover mold 8, and a vacuum bag is made in the upper mold, and the vacuum bag is connected to the fuselage air bag 6 through the sealant, and the vacuum pre-compaction treatment is performed again to ensure that the fuselage air bag 6 and the fuselage 5 shape fit perfectly.

[0076] Inflation and curing Remove the vacuum bag made by the upper mold, lock the fuselage front cover mold 4 and the fuselage rear cover mold 3, close the fuselage round cover mold 8, and inflate the air nozzle 7 of the fuselage air bag 6. Initially inflate to 0.4Mpa, keep it for a while to check whether the air pressure remains stable. After confirming that it is correct, adjust the air pressure to 0.6Mpa, put the mold into the curing furnace, and heat it to 125℃ for curing. During the curing process, the pressure environment provided by the fuselage air bag 6 helps the composite material prepreg to fit tightly and cure.

[0077] Demolding and trimming After the curing is completed, the demoulding operation is performed to take out the formed fuselage 5 structure, and the product fuselage 5 is trimmed to ensure that the surface is smooth and defect-free to meet the final product requirements.

[0078] Through the above steps, the present invention realizes the one-piece forming of the composite material fuselage by using the airbag-assisted forming technology, which not only gives full play to the performance advantages of the composite material, but also reduces the process cost, reduces the weight, and improves the production efficiency.

[0079] The present invention makes the carbon fiber prepreg closely fit the mold shape through the uniform expansion of the fuselage airbag 6 during the curing process, effectively avoiding the generation of defects such as gaps and bubbles, thereby significantly improving the molding accuracy of the product. The uniform pressure provided by the fuselage airbag 6 helps to reduce the thermal stress and deformation of the product during the curing process, so that the final product has better dimensional stability and shape retention. The auxiliary effect of the fuselage airbag 6 makes the product surface smoother and flatter, reducing surface defects that may occur in traditional processes, such as wrinkles and dents.

[0080] After being fully cured, the carbon fiber prepreg of the present invention forms a composite material with excellent mechanical properties, so that the product body 5 has high strength and high rigidity and can withstand large loads and impacts. Through precise curing treatment, the resin matrix forms a stable three-dimensional network structure, which gives the product good thermal stability and enables it to maintain stable performance in high or low temperature environments.

[0081] According to needs, other functional materials, such as conductive materials, thermal conductive materials, etc., can be added to the product body 5 to achieve the multifunctionality of the product.

[0082] Compared with the traditional process, the present invention reduces multiple processing steps, such as cutting and splicing of prepreg, thereby simplifying the process flow and improving production efficiency. Since the fuselage airbag 6 is used to assist in molding, the prepreg can fit the mold shape more fully, reducing material waste and reducing production costs.

[0083] The present invention adopts a more efficient heating method during the curing process, and due to the simplification of the process flow, the overall energy consumption is also reduced.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An airbag-assisted fuselage integral molding method, characterized in that: The following steps are involved: a) Based on the fuselage dimensions, the mold is precisely designed and manufactured using Fibersim software to develop the product size and shape, ensuring that the cut prepreg completely matches the fuselage shape; b) Precisely laying the prepreg on the fuselage lower mold (1) and the fuselage upper mold (2) according to the shape of the fuselage, and using a vacuum pre-compaction process to ensure that the vacuum degree is above 0.085Mpa to remove air between the materials and ensure that the prepreg fits tightly; c) After the paving is completed, auxiliary materials are laid on the prepreg, and then the upper mold (2) of the fuselage is turned over, and accurately positioned with the lower mold (1) of the fuselage through positioning pins and fastened with bolts to ensure the stability and accuracy of the mold during the mold closing process; d) After the upper and lower molds are closed, the overlapping edges are carefully arranged to ensure that the overlapping edges are tightly fitted, and then the fuselage air bag (6) is placed from the fuselage round cover mold (8), and the vacuum bag made in the upper mold is connected to the fuselage air bag (6) through a sealant, and vacuum pre-compacted again to ensure that the fuselage air bag (6) and the fuselage shape fit perfectly; e) Remove the vacuum bag made by the upper mold, lock the fuselage front cover mold (4) and the fuselage rear cover mold (3), close the fuselage round cover mold (8), inflate the air nozzle (7) of the fuselage air bag (6), and check the air pressure gauge. Initially inflate to 0.4Mpa, keep the air pressure unchanged for 5 minutes, and after confirming that it is correct, adjust the air pressure to 0.6Mpa, then put the mold into the curing oven, and heat it to 125℃ for curing; f) After curing is completed, demoulding is performed and the product body (5) is trimmed to obtain the final airbag-assisted body integrated molding product.

2. The airbag-assisted fuselage integral molding method according to claim 1, characterized in that: The Fibersim software is used to accurately develop product size and shape, ensuring that the cut carbon fiber prepreg is highly compatible with the fuselage shape.

3. The airbag-assisted fuselage integral molding method according to claim 1, characterized in that: The vacuum degree of the vacuum pre-compacting process is controlled at above 0.085 MPa to ensure close fit between the prepreg and the auxiliary materials and to exclude air between the materials.

4. The airbag-assisted fuselage integral molding method according to claim 1, characterized in that: The fuselage mold comprises a fuselage lower mold (1), a fuselage upper mold (2), a fuselage front cover mold (4), a fuselage rear cover mold (3) and a fuselage round cover mold (8), and the fuselage upper mold (2) is provided with two openings at both ends in addition to a single-side opening, so as to facilitate installation of other equipment after the fuselage is formed and facilitate arrangement and adjustment of the position of the fuselage air bag (6) during the inflation process of the fuselage air bag (6).

5. The airbag-assisted fuselage integral molding method according to claim 4, characterized in that: The inflation step of the fuselage airbag (6) includes initially inflating the airbag to 0.4 Mpa, maintaining the pressure for 5 minutes, and checking whether the air pressure remains constant. After confirmation, the air pressure is adjusted to 0.6 Mpa to ensure the stability of the fuselage airbag (6) during the curing process and the performance of the final product.

6. The airbag-assisted fuselage integral molding method according to claim 5, characterized in that: The curing step includes heating the mold to 125° C. for curing to ensure sufficient curing of the carbon fiber prepreg and the fuselage airbag (6) and the final performance of the product.

7. The airbag-assisted fuselage integral molding method according to claim 1, characterized in that: The final product body (5) is obtained through demoulding and trimming steps.

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