A method of forming a complex composite inlet duct cover

Abstract

This invention relates to a method for molding an irregularly shaped composite material air intake protective cover. The method includes: manufacturing a protective cover molding mold and a rubber core mold according to the outer dimensions and molding requirements of the protective cover; laying up the rubber core mold to obtain front and rear reinforcing ribs covered with prepreg layers; positioning the rear reinforcing rib in the protective cover molding mold; applying a film to the connecting seat and positioning the connecting seat in the protective cover molding mold; positioning the front reinforcing rib in the protective cover molding mold; laying up the skin of the protective cover body and performing vacuum pre-compacting treatment; and closing, curing, and demolding to obtain the irregularly shaped composite material air intake protective cover. This invention effectively solves the problems of molding and demolding difficulties in irregularly shaped composite material protective covers, ensuring both surface accuracy and internal quality of the product, resulting in a high-quality final product with good overall integrity, and significantly reducing molding and subsequent machining costs.

Description

Technical Field

[0001] This invention belongs to the field of integral molding technology for irregularly shaped composite materials, and particularly relates to a molding method for aircraft protective covers. Background Technology

[0002] The air intake shield is a protective component for the air intake of an air-breathing aircraft. Located on the underside of the aircraft, it plays a role in stabilizing the airflow field and protecting the internal spacecraft. It is an irregularly shaped and complex shell, constructed from high-temperature resistant, high-strength, and high-modulus carbon fiber thermosetting resin-based composite material. This material is often used to replace the structural aluminum alloys commonly used in aircraft, reducing structural weight and increasing load-bearing capacity. However, high-temperature resistant composite materials typically have high curing temperatures. After curing, once cooled to room temperature, the presence of internal curing and thermal stresses, along with the anisotropic nature of the composite material, makes the product prone to deformation and warping, affecting dimensional accuracy and leading to dimensional deviations. Furthermore, the aircraft air intake shield is a thin-walled, open structure with a large slope, making manufacturing difficult. Molding and demolding are challenging, and the resin has low viscosity and high fluidity at high temperatures, making it prone to runaway and causing delamination and porosity defects within the product.

[0003] For large-sized, irregularly shaped air intake dome structures, product forming, deformation, and delamination remain key technical problems that urgently need to be solved, which seriously restricts the promotion and application of composite materials in the field of aircraft. Summary of the Invention

[0004] The technical problem solved by the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a molding method for an irregular composite material air intake protective cover. After integral molding and curing, the overall performance, surface accuracy and internal quality of the air intake protective cover can be guaranteed. Compared with conventional methods, the production efficiency is greatly improved.

[0005] The specific technical solution of this invention is as follows:

[0006] A method for molding an irregularly shaped composite material air intake protective cover includes the following steps:

[0007] Based on the external dimensions and molding requirements of the protective cover, manufacture the protective cover molding mold and the rubber core mold;

[0008] The rubber core mold is layered to obtain front and rear reinforcing ribs covered with prepreg layers;

[0009] The rear reinforcing rib is positioned in the protective cover molding mold;

[0010] Apply a film to the connector and position it in the protective cover molding mold;

[0011] The front reinforcing ribs are positioned in the protective cover molding mold;

[0012] The protective cover body is laid with skin layers and then vacuumed and pre-compacted.

[0013] The process involves mold closing, curing, and demolding to obtain a protective cover for the air intake duct made of irregularly shaped composite material.

[0014] Furthermore, the manufacturing of the protective cover molding mold and rubber core mold according to the outer dimensions and molding requirements of the protective cover includes: manufacturing the protective cover molding mold and rubber core mold using P20 mold steel according to the outer dimensions and molding requirements of the protective cover. The protective cover molding mold has an upper and lower mold structure. The lower mold has a segmented structure, consisting of a lower mold base frame, limiting posts, stops, side strips, and multiple core blocks. The core blocks are limited to the lower mold base frame by the grooves in the lower mold base frame. The side strips are folded strips installed around the edges of the core blocks to support the upper mold and ensure the molding quality of the sides of the protective cover. The limiting posts are cylindrical and used to determine whether the side strips are securely fastened. The rubber core mold has an upper and lower mold structure. The lower mold has two grooves for molding the front reinforcing ribs and the rear reinforcing ribs, respectively. The outer surface of the upper mold has a glue inlet and a glue outlet.

[0015] Further, the process of laying up the rubber core mold to obtain the front and rear reinforcing ribs covered with the prepreg layer group includes: pouring molten rubber (silicone rubber) after vacuuming and degassing into the rubber inlet of the rubber core mold to uniformly expel air from the mold until the rubber overflows from the outlet, curing at room temperature for 12 hours, demolding to obtain the front / rear rubber core mold, and then directly covering the prepreg layer group on the rubber core mold according to the layup sequence, sealing it with a vacuum bag, and vacuuming and pre-compacting it to obtain the front / rear reinforcing ribs covered with the prepreg layer group.

[0016] Furthermore, the positioning of the rear reinforcing rib in the protective cover molding mold includes: assembling the metal core block at the large end of the mold into the positioning groove of the lower mold bottom frame; installing the metal core block at the bottom of the rear reinforcing rib into the positioning groove of the lower mold bottom frame; laying a layer of plain carbon fiber prepreg on the upper surface of the metal core block; and then placing the rear reinforcing rib covered with the prepreg layer onto the plain carbon fiber prepreg on the metal core block.

[0017] Furthermore, the process of applying a film to the connector and positioning the connector in the protective cover molding mold includes: applying multiple layers of adhesive film to all contact areas between the connector and the composite material cover, installing the central metal core block containing the connector in the positioning groove of the lower mold bottom frame, and simultaneously installing the remaining central metal core block in the positioning groove of the lower mold bottom frame.

[0018] Furthermore, the positioning of the front reinforcing rib in the protective cover molding mold includes: installing the metal core block at the bottom of the front reinforcing rib into the positioning groove of the lower mold bottom frame, laying a layer of plain carbon fiber prepreg on the upper surface of the metal core block, and placing the front reinforcing rib covered with the prepreg layer on the plain carbon fiber prepreg on the metal core block.

[0019] Furthermore, the process of laying the protective cover skin and performing vacuum pre-compaction includes:

[0020] 1) Assemble the metal core blocks at the small end of the mold into the positioning grooves of the lower mold base frame in sequence.

[0021] 2) Fold the plain carbon fiber prepreg with front / rear reinforcing ribs up along the mold direction. Do not cut it during the folding process. Lay a layer of plain carbon fiber prepreg on the remaining mold surface, and then lay the thickened area of ​​the cover and the skin area in sequence. Seal with a vacuum bag and perform the first vacuum pre-compacting treatment.

[0022] 3) Before laying the protective cover skin again, trim the prepreg along the edge of the mold, lay the remaining skin layers and perform a second vacuum pre-compaction. After the pre-compaction is completed, trim any excess flash around the perimeter.

[0023] 4) After cleaning the entire surface of the skin, lay the last layer of plain carbon fiber prepreg and trim it according to the edge lines of the mold.

[0024] Furthermore, the mold closing, curing, and demolding processes include:

[0025] 1) Tighten the fastening screws between the metal core block of the mold and the bottom frame of the lower mold. After placing the pressure block at the upper end of the connecting seat into place, tighten the fastening screws on the pressure block to ensure that the connecting seat is installed in place.

[0026] 2) Assemble the front stop block and the three side strips on the left, right and rear ends of the mold into the corresponding positions on the lower mold, and use the pressure screws to push the side strips to fit tightly against the core block;

[0027] 3) Close the upper mold, set the temperature and pressure according to the prepreg process parameters, and then gradually increase the pressure in three to four times until the mold is tightly closed. After ensuring that the gap between the upper and lower molds is no more than 0.1mm, tighten the pressure screws of the side strip to ensure that the limit posts on both sides do not protrude from the outside of the mold. During the entire heating and curing process of the protective cover, the mold must be kept within the set temperature range of ±5℃.

[0028] 4) Cooling and demolding after curing: Cold circulation cooling pneumatic demolding, remove the lower mold and core block to obtain the anisotropic composite material air inlet protective cover.

[0029] Furthermore, during the front / rear reinforcing rib layup process, adjacent prepreg strips in the same layer are laid in a butt joint manner, and the butt joints between different layers are staggered by 5-10mm.

[0030] Furthermore, the vacuum pre-compaction treatment during the front / back reinforcing rib layup process is as follows: the outer surface of the reinforcing rib rubber core mold with the laid layers is wrapped sequentially with a non-porous membrane, a breathable felt, and a vacuum bag, and sealed with a sealing strip to ensure airtightness. It is then placed in an oven and kept at a temperature of 70-90℃ for 60-80 minutes. A vacuum is then drawn, and the vacuum degree reaches above -0.09MPa.

[0031] Furthermore, the pre-compaction process after laying the protective cover skin is as follows: the lower mold of the protective cover is placed on a steel plate, and a non-porous membrane, a breathable felt, and a vacuum bag are wrapped sequentially on the outer surface of the mold after the cover is laid. The vacuum bag is then attached to the steel plate to seal the entire lower mold of the protective cover. The airtightness is ensured by sealing with a sealing strip. The mold is then placed in an oven and kept at a temperature of 50–90°C for 50–80 minutes. A vacuum is then drawn, and the vacuum degree reaches above -0.09 MPa.

[0032] The present invention also provides an irregularly shaped composite material air intake protective cover formed by the above method.

[0033] The advantages of this invention compared to the prior art are as follows:

[0034] This invention adopts an integrated molding process. Through the pre-pressing process and the close cooperation of the side strips and limiting posts, and the use of silicone rubber for auxiliary pressure and front and rear reinforcing ribs, it can effectively solve the problems of molding and demolding difficulties of irregular composite material protective covers. While ensuring the surface accuracy of the product, it can also ensure the internal quality of the product (the area occupied by flaw detection defects is less than 5%). The process is stable, the final product has good integrity, and the molding manufacturing and subsequent machining costs are greatly reduced. Attached Figure Description

[0035] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention. They do not constitute an undue limitation of the invention. The proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0036] Figure 1 This is a flowchart of the method of the present invention;

[0037] Figure 2 This is a schematic diagram of the irregular composite material air intake protective cover of the present invention;

[0038] Figure 3 This is a top view of the molding die for the irregular composite material air intake protective cover of the present invention;

[0039] Figure 4 This is a cross-sectional view of the molding die for the irregular composite material air intake protective cover of the present invention;

[0040] Figure 5 This is a schematic diagram of the pressing block of the present invention;

[0041] Figure 6 This is a schematic diagram of the rubber molding die for the irregular composite material air intake duct protective cover of the present invention;

[0042] Figure 7 This is a SEM image of the irregular composite material air intake protective cover of the present invention.

[0043] List of reference numerals in the attached diagram:

[0044] 0. Air intake duct protective cover; 1. Connecting seat; M1. Limiting post; M2. Pressure screw; M3. Fastening screw; M4. Positioning groove; M5. Upper mold; M6. Lower mold base frame; M7. Side strip; M8. Metal core block; M9. Stop block; M10. Pressure plate; M11. Pressure plate fastening screw; M12. Groove for reinforcing ribs before molding; M13. Groove for reinforcing ribs after molding; M14. Glue inlet; M15. Glue outlet. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The overall process of the integral molding method for the irregular composite material protective cover of the present invention is as follows: Figure 1 As shown, the main steps include: mold design, manufacturing and assembly, front and rear reinforcing ribs layup, rear reinforcing rib positioning, connector film application and connector positioning, front reinforcing rib positioning, cover skin layup, multiple product pre-compaction, mold closing, curing, demolding and CT inspection, etc. Figure 2 This is a schematic diagram of the irregular composite material air intake protective cover of the present invention, in which the two dashed lines indicate the location of the reinforcing ribs.

[0047] In one embodiment of the present invention, the method for molding the irregular composite material air intake protective cover specifically includes the following steps:

[0048] (1) Based on the external dimensions and molding requirements of the protective cover, P20 mold steel is used to manufacture the protective cover molding mold and rubber core mold. The protective cover molding mold is divided into an upper mold M5 and a lower mold. The lower mold has a segmented structure, consisting of a lower mold base frame M6, limiting posts M1, stop blocks M9, side strips M7, and multiple metal core blocks M8, as shown below. Figure 3 , Figure 4 As shown. The rubber core mold has an upper and lower mold structure, as... Figure 6 As shown, the lower mold has a groove M12 for reinforcing ribs before molding and a groove M13 for reinforcing ribs after molding. The outer surface of the upper mold has a glue inlet M14 and a glue outlet M15.

[0049] (2) Pour the vacuum-sealed, bubble-removed rubber liquid into the rubber inlet M14 of the rubber core mold to uniformly expel air from the mold until the rubber overflows from the outlet M15. Cure at room temperature for 12 hours, demold to obtain the front / rear rubber core mold, and then directly cover the prepreg layer group on the rubber core mold according to the layering sequence. The thickness of a single layer of prepreg is 0.5 mm, and the number of layers is 3 to 6. Seal with a vacuum bag and perform vacuum pre-compacting treatment until the predetermined number of layers is obtained to obtain the front / rear reinforcing ribs covered with prepreg.

[0050] (3) Place the large end of the mold (such as...) Figure 3 The five segmented metal core blocks (as shown) are assembled in the positioning groove M4 of the lower mold bottom frame M6;

[0051] (4) Install the metal core block at the bottom of the rear reinforcing rib into the positioning groove M4 of the lower mold, lay a 0.2mm thick plain carbon cloth prepreg on the upper surface of the metal core block, and then place the rear reinforcing rib covered with the prepreg layer group in step (2) on the plain carbon cloth prepreg on the metal core block.

[0052] (5) Apply 2 to 4 layers of adhesive film to all contact areas between the connector 1 and the composite material cover, and install the central metal core block containing the connector 1 into the positioning groove M4 of the lower mold, while also installing the remaining central metal core block into the positioning groove M4 of the lower mold. The connector 1 is used to fix the air intake protective cover to other parts of the aircraft.

[0053] (6) Install the metal core block at the bottom of the front reinforcing rib into the positioning groove M4 of the lower mold, lay a layer of 0.2mm thick plain carbon cloth prepreg on the upper surface of the metal core block, and place the front reinforcing rib in step (2) on the plain carbon cloth prepreg on the metal core block.

[0054] (7) Place the small end of the mold (such as...) Figure 3 The large metal core blocks (as shown) are sequentially assembled in the positioning groove M4 of the lower mold;

[0055] (8) Fold the plain weave carbon fiber prepreg with front / rear reinforcing ribs up along the mold direction (covering the front / rear reinforcing ribs). Do not cut it during the folding process. Lay a 0.2mm thick layer of plain weave carbon fiber prepreg on the remaining mold surface. Then lay the 3-8mm thickened area and 1-4mm skin area of ​​the cover in sequence. Seal with a vacuum bag and perform the first vacuum pre-compacting treatment until the predetermined number of layers is reached.

[0056] (9) Before laying the protective cover skin again, trim the prepreg along the edge of the mold and lay the remaining skin layer. Seal it with a vacuum bag and perform a second vacuum pre-compaction until the skin thickness is reached. After the pre-compaction is completed, trim the excess flash around the perimeter.

[0057] (10) After cleaning the entire surface of the skin, lay the last layer of 0.2mm thick plain carbon cloth prepreg and trim it according to the edge lines of the mold.

[0058] (11) Tighten the fastening screws M3 between the metal core block of the mold and the bottom frame M6 of the lower mold. After placing the pressure block M10 at the upper end of the connecting seat 1 into place, tighten the fastening screws M11 on the pressure block, as follows. Figure 5 As shown, ensure the connector is installed correctly;

[0059] (12) Assemble the stop block M9 at the front end of the mold and the three side strips M7 at the left and right rear ends in the corresponding positions of the lower mold, and use the pressure screws M2 (such as Figure 3 (As shown) Push the edge strip tightly against the core block;

[0060] (13) Close the upper mold and place the assembled mold on the press. When the mold temperature is 140℃, gradually increase the pressure in three to four times until the mold is tightly closed. After ensuring that the gap between the upper and lower molds is no more than 0.1mm, tighten the pressure screw M2 of the side strip to ensure that the limit posts on both sides do not protrude from the outside of the mold. Keep the mold warm and pressurized for 2 hours. When the mold temperature is raised to 180℃, keep the mold warm and pressurized for 2 hours. During the entire heating and curing process of the protective cover, the mold must be kept within the set temperature range of ±5℃.

[0061] (14) Cooling and demolding after curing: cold circulation cooling pneumatic demolding, pull out the lower mold and core block to obtain the anisotropic composite material air inlet protective cover.

[0062] According to some preferred embodiments, during the front / rear reinforcing rib layup process in step (2), adjacent prepreg strips in the same layer are laid in a butt joint manner, and the butt joints between different layers are staggered by 5-10 mm. The vacuum pre-compaction treatment in step (2) is as follows: the outer surface of the reinforcing rib rubber core mold with the laid layers is wrapped in a non-porous membrane, a breathable felt, and a vacuum bag in sequence, and the airtightness is ensured by sealing strips. It is then placed in an oven, kept at a temperature of 70-90℃ for 60-80 minutes, and a vacuum is drawn until the vacuum degree reaches above -0.09MPa.

[0063] According to some preferred embodiments, in steps (8) and (9), the vacuum pre-compaction process is as follows: the lower mold of the protective cover is placed on a steel plate, and a non-porous membrane, a breathable felt, and a vacuum bag are wrapped sequentially on the outer surface of the mold covered with the cover. The vacuum bag is then attached to the steel plate to seal the entire lower mold of the protective cover. The airtightness is ensured by attaching the sealing strip. The mold is then placed in an oven with a heat preservation temperature of 50-90°C and a heat preservation time of 50-80 minutes. A vacuum is then drawn, and the vacuum degree reaches -0.09 MPa or higher.

[0064] According to some preferred embodiments, the prepreg is a carbon fiber reinforced resin-based epoxy prepreg (e.g., T700 / 8522 ​​high-temperature epoxy prepreg), where 8522 refers to a high-temperature epoxy resin. The material processed with this resin and unidirectional layers or carbon cloth is called T700 / 8522 ​​high-temperature epoxy prepreg layer or T700 / 8522 ​​high-temperature epoxy plain weave carbon cloth prepreg.

[0065] Figure 7 This is a SEM image of the irregular composite material air intake protective cover of the present invention, located at... Figure 2 In the middle position, it can be seen that the carbon fiber is tightly wrapped by the matrix without gaps or delamination, indicating that the internal quality of the air intake protective cover after molding is stable.

[0066] It is worth noting that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution. In the absence of any conflict between the solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0067] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for molding an irregularly shaped composite material air intake protective cover, characterized in that, Includes the following steps: Based on the external dimensions and molding requirements of the protective cover, manufacture the protective cover molding mold and the rubber core mold; The rubber core mold is layered to obtain front and rear reinforcing ribs covered with prepreg layers; The rear reinforcing rib is positioned in the protective cover molding mold; Apply a film to the connector and position it in the protective cover molding mold; The front reinforcing ribs are positioned in the protective cover molding mold; The protective cover is covered with a layer of skin and then vacuumed and pre-compacted. The mold is closed, cured, and demolded to obtain a shaped composite material air intake protective cover. The protective cover molding die has an upper and lower mold structure. The lower mold includes a lower mold base frame, limiting posts, stop blocks, side strips, and multiple core blocks. The core blocks are limited to the lower mold base frame by grooves. The side strips are folded strips installed around the edges of the core blocks to support the upper mold and ensure the molding quality of the sides of the protective cover. The limiting posts are cylindrical and used to determine whether the side strips are securely fastened. The rubber core mold has an upper and lower mold structure. The lower mold has two grooves for molding the front reinforcing ribs and the rear reinforcing ribs, respectively. The outer surface of the upper mold has a glue inlet and a glue outlet. The process of laying up the rubber core mold to obtain the front and rear reinforcing ribs covered with the prepreg layer group includes: pouring molten rubber that has been vacuumed and de-aired into the rubber inlet of the rubber core mold to uniformly expel air from the mold until the rubber overflows from the outlet, performing room temperature vulcanization, demolding to obtain the front and rear rubber core molds, and then directly covering the prepreg layer group on the rubber core mold according to the layup sequence, sealing it with a vacuum bag, and vacuuming and pre-compacting it to obtain the front and rear reinforcing ribs covered with the prepreg layer group.

2. The method according to claim 1, characterized in that, During the layup of the front and rear reinforcing ribs, adjacent prepreg strips in the same layer are laid together by butt joints, and the butt joints between different layers are staggered by 5-10 mm. The vacuum pre-compaction treatment during the layup of the front and rear reinforcing ribs is as follows: the outer surface of the rubber core mold of the reinforcing ribs with the laid layers is wrapped in a non-porous membrane, a breathable felt, and a vacuum bag in sequence, and the airtightness is ensured by sealing strips. The mold is then placed in an oven and kept at a temperature of 70-90℃ for 60-80 minutes. A vacuum is then applied, and the vacuum degree reaches above -0.09 MPa.

3. The method according to claim 1, characterized in that, Positioning the rear reinforcing rib in the protective cover molding mold includes: installing the metal core block at the bottom of the rear reinforcing rib into the positioning groove of the lower mold bottom frame, laying a layer of plain carbon fiber prepreg on the upper surface of the metal core block, and then placing the rear reinforcing rib covered with the prepreg layer on the plain carbon fiber prepreg on the metal core block.

4. The method according to claim 1, characterized in that, The process of applying a film to the connector and positioning the connector in the protective cover molding mold includes: applying multiple layers of adhesive film to all contact areas between the connector and the composite material cover, installing the central metal core block containing the connector in the positioning groove of the lower mold bottom frame, and simultaneously installing the remaining central metal core block in the positioning groove of the lower mold bottom frame.

5. The method according to claim 1, characterized in that, Positioning the front reinforcing rib in the protective cover molding mold includes: installing the metal core block at the bottom of the front reinforcing rib into the positioning groove of the lower mold bottom frame, laying a layer of plain carbon fiber prepreg on the upper surface of the metal core block, and placing the front reinforcing rib covered with the prepreg layer on the plain carbon fiber prepreg on the metal core block.

6. The method according to claim 1, characterized in that, The process of laying the skin layer of the protective cover and performing vacuum pre-compaction includes: Fold the plain carbon fiber prepreg with front / rear reinforcing ribs up along the mold direction. Do not cut it during the folding process. Lay a layer of plain carbon fiber prepreg on the remaining mold surface, and then lay the thickened area of ​​the cover and the skin area in sequence. Seal with a vacuum bag and perform the first vacuum pre-compacting treatment. Before laying the protective cover skin again, trim the prepreg along the edge of the mold, lay the remaining skin layers and perform a second vacuum pre-compaction. After the pre-compaction is completed, trim any excess flash around the perimeter. After cleaning the entire surface of the skin, lay the last layer of plain carbon fiber prepreg and trim it according to the edge lines of the mold. The vacuum pre-compaction process is as follows: the lower mold of the protective cover is placed on a steel plate, and a non-porous membrane, a breathable felt, and a vacuum bag are wrapped sequentially on the outer surface of the mold after the cover is laid. The vacuum bag is then glued to the steel plate to seal the entire lower mold of the protective cover. The airtightness is ensured by sealing with a sealing strip. The mold is then placed in an oven and kept at a temperature of 50-90℃ for 50-80 minutes. A vacuum is then drawn, and the vacuum degree reaches above -0.09MPa.

7. The method according to claim 1, characterized in that, The mold closing, curing, and demolding processes include: Tighten the fastening screws between the metal core block of the mold and the bottom frame of the lower mold. After placing the pressure block at the upper end of the connecting seat into place, tighten the fastening screws on the pressure block to ensure that the connecting seat is installed in place. Assemble the front stop block and the three side strips on the left, right and rear ends of the mold into the corresponding positions of the lower mold, and use the pressure screws to push the side strips to fit tightly against the core block; Close the upper mold, set the temperature and pressure according to the prepreg process parameters, and then gradually increase the pressure in three to four times until the mold is tightly closed. After ensuring that the gap between the upper and lower molds is no more than 0.1mm, tighten the pressure screws of the side strip to ensure that the limit posts on both sides do not protrude from the outside of the mold. During the entire heating and curing process of the protective cover, the mold must be kept within the set temperature range of ±5℃. After curing, the material is cooled and demolded to obtain an anisotropic composite material air intake protective cover.

8. An irregularly shaped composite material air intake protective cover formed by the method according to any one of claims 1 to 7.

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