Asymmetrical curved honeycomb sandwich structure light shield and preparation method thereof

Abstract

The application provides a special-shaped curved honeycomb sandwich structure light shield and a preparation method thereof, which comprises the following steps: S1, manufacturing each component of the light shield; S2, processing and pre-assembling according to the shape; S3, surface treatment; S4, sequentially assembling; S5, preheating and vacuumizing; S6, locally uniformizing pressure and guiding flow at the position of the special-shaped curved surface; S7, heating, pressurizing and solidifying; S8, reinforcing the joint position; and S9, demolding. In the application, the inner skin is not split as a whole, the continuity of the fiber as a whole is ensured, the stiffness and strength are better, the light and efficient structure is obtained, the number of molds is reduced through mold sharing, the fit degree of the skin profile and the mold under the high-temperature solidification state is ensured, the forming precision is improved through the design of the skin resetting and positioning, the production efficiency is improved through the introduction of the preheating treatment, the local uniformizing pressure and the flow guiding treatment and other modes, the product bonding quality is improved, and the manufacturing precision and the stability of the product can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, specifically to a non-circular curved honeycomb sandwich structure light shield and its preparation method. Background Technology

[0002] A lens hood is a crucial component of the optical system of a space camera. Its primary function is to suppress stray light, significantly impacting the camera's build quality and performance. The lens hood not only blocks some atmospheric light and other stray light from entering the camera lens, but also, by utilizing its length, surface material properties, and internal cavity contours, maximizes the absorption of stray light that has already entered the lens hood, thereby improving the camera's signal-to-noise ratio.

[0003] In addition to withstanding the harsh mechanical environment of satellite transportation and launch, such as static overload, dynamic load impact, and random vibration, sunshades are sometimes directly exposed to space. Therefore, high requirements are placed on the materials and manufacturing processes of sunshades. With the development towards "functionality" and "lightweighting," more and more optical remote sensor sunshades are using various composite materials. For example, the main body of the sunshade is made of fiber (carbon fiber, aramid fiber) reinforced resin matrix composites or honeycomb sandwich structures.

[0004] The development of space remote sensing technology has made the structure of light shields more complex and diverse. The structure of light shields has evolved from the original regular cylindrical and conical shapes to various irregular shapes. Among them, light shields with irregular curved honeycomb sandwich structures are widely used, mainly to block and absorb external stray radiation or reduce the temperature gradient of the window to improve imaging quality or detection performance.

[0005] Currently, the method for manufacturing irregularly shaped curved honeycomb sandwich structure light shields involves separately forming inner and outer skins of the irregular curved surface, and then overlapping the inner and outer skins in a segmented manner to form the sandwich structure. To ensure the connection strength at the segmented locations and the inner cavity contour of the light shield, reinforcement is applied at the segmented locations, with internal reinforcement for the inner skin and external reinforcement for the outer skin. Simultaneously, to ensure the thickness of the light shield, the honeycomb sandwich structure at the segmented locations must be short, and the honeycomb cells need to be spliced ​​separately, with the seams filled with adhesive film or expanding foam. This method causes discontinuities in the skin and honeycomb, increases weight, hindering lightweighting, and increases the amount of adhesive used, leading to increased gas escape in a vacuum environment, which affects the imaging of the optical system. After the skin is segmented, the requirements for the inner cavity seams are high, and there is often a large amount of adhesive overflow at the inner cavity seams, making subsequent cleaning difficult. Currently, no effective solution has been proposed to address these numerous technical problems of the existing method for manufacturing irregularly shaped curved honeycomb sandwich structure light shields.

[0006] Therefore, there is a need to provide a method for preparing a light shield with an irregular curved honeycomb sandwich structure, which can improve production efficiency and product bonding quality, especially providing good guidance for bonding of sandwich structures with irregular curved surfaces, and can greatly improve the manufacturing precision and stability of the product. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a light shield with an irregular curved honeycomb sandwich structure and its preparation method.

[0008] The present invention provides a method for preparing a light shield with an irregular curved honeycomb sandwich structure, comprising the following steps:

[0009] Step S1: The inner skin, outer skin, honeycomb core, and embedded parts of the light shield are manufactured respectively.

[0010] Step S2: Process the outer skin according to its shape, divide the outer skin into multiple segments, pre-assemble the inner skin, the outer skin, the honeycomb core and the embedded parts, and adjust the assembly gap.

[0011] Step S3: Perform surface treatment on the inner skin, the outer skin, the honeycomb core, and the embedded parts;

[0012] Step S4: First, the inner skin is assembled onto the mold, then the honeycomb core and the embedded parts are assembled in sequence, and finally the outer skin is assembled by overlapping segments to form an integral sandwich structure.

[0013] Step S5: Make a vacuum bag, preheat and vacuum it;

[0014] Step S6: Perform local pressure equalization and flow diversion treatment on the irregular curved surface, and remake the vacuum bag;

[0015] Step S7: Perform heat and pressure curing treatment;

[0016] Step S8: Reinforce the seam of the outer side of the outer skin.

[0017] Step S9: Demolding yields a light shield with an irregular curved honeycomb sandwich structure.

[0018] Preferably, in step S1, both the inner skin and the outer skin are formed using a positive mold. During layup, the layup angle trajectory of the composite material is first simulated on the mold, and the layers are laid up according to the trajectory.

[0019] Preferably, in step S2, the outer skin is segmented by overlapping sections, and the outer skin is divided along the length of the light shield on its plane.

[0020] Preferably, in step S2, the inner skin is provided with positioning ear pieces, and the positioning ear pieces are provided with pin holes and upper and lower waist-shaped holes; the upper and lower edges of each segment of the outer skin are provided with left and right waist-shaped holes, and the middle position is provided with upper and lower waist-shaped holes.

[0021] Preferably, in step S4, the mold to which the inner skin is assembled shares the same core mold as the molding mold of the inner skin.

[0022] Preferably, in step S5, the integral sandwich structure is heated to 65°C to 80°C along with the mold in a furnace, and a vacuum is drawn with a vacuum degree not lower than -0.055 MPa.

[0023] Preferably, in step S6, pressure equalization is achieved by placing a pressure equalization plate, the pressure equalization plate being circumferentially extended outward by 50-60mm on one side at the transition position between the edge and the plane, the pressure equalization plate comprising a thin metal plate or a composite material plate; and flow guidance is achieved by placing a flow guide net on the outside of the pressure equalization plate.

[0024] Preferably, in step S7, the pressure curing molding process includes oven curing molding process, autoclave curing molding process, and vacuum bag pressure curing molding process.

[0025] Preferably, in step S8, the outer skin is reinforced at the segment position with narrow strips of the same material, and the width of the reinforcement is increased by 15-25mm from the center of the seam to both sides.

[0026] The irregular curved honeycomb sandwich structure light shield provided by the present invention is prepared by the above-mentioned preparation method of the irregular curved honeycomb sandwich structure light shield.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention ensures the continuity of the fiber structure with good rigidity and strength by not segmenting the inner skin as a whole, thus achieving a lightweight and efficient structure. It solves the problems of increased weight caused by the need for reinforcement and foam filling at the segmentation points during segmented molding, reduced new interfaces, and the need to shorten the honeycomb height at the segmentation points due to internal reinforcement, which requires splicing the honeycomb and reduces the strength compared to continuous honeycomb.

[0029] 2. This invention uses a sandwich structure inner skin mold and a sandwich structure adhesive assembly mold to share the same mold, which reduces the number of molds and the problem of poor surface matching caused by different molds, and also ensures the fit between the skin surface and the mold under high temperature curing.

[0030] 3. This invention improves molding accuracy through the design of skin resetting and positioning, solves the problem of high-precision skin resetting during sandwich structure molding, and also restricts unidirectional movement when the skin extends, thus solving the problem of disordered slippage during skin extension.

[0031] 4. This invention solves the problems of skin not fitting well with the mold due to the coefficient of thermal expansion at room temperature and high temperature, uneven pressure at different curvature positions during sandwich structure molding, wrinkles or depressions and bulges that the skin cannot stretch, by introducing preheating treatment, local pressure equalization and flow guiding treatment.

[0032] 5. This invention can improve production efficiency and product bonding quality, especially providing good guidance for bonding sandwich structures with irregular curved surfaces, which can greatly improve the manufacturing precision and stability of the products. Attached Figure Description

[0033] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0034] Figure 1 This is a schematic diagram illustrating the main features of the irregular curved honeycomb sandwich structure light shield of the present invention;

[0035] Figure 2 This is a schematic diagram illustrating the main skin layering of the present invention;

[0036] Figure 3 This is a partial schematic diagram illustrating the positioning lugs and surrounding strip holes during the curing of the sandwich structure, which are the main features of this invention.

[0037] Figure 4 This is a partial schematic diagram illustrating the positioning holes of the solidified outer skin of the sandwich structure, which is the main feature of this invention.

[0038] Figure 5 This is a schematic diagram of the auxiliary layer during the curing of the irregular curved honeycomb sandwich structure light shield, which is the main feature of this invention.

[0039] As shown in the figure:

[0040] Core mold 1; Light shield product 2; Isolation film 3

[0041] 4. Pressure equalizing plate; 5. Air guide net; 6. Breathable material

[0042] 7 Vacuum bags 8 Sealing strips Detailed Implementation

[0043] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0044] Example 1

[0045] like Figure 1-5 As shown, the present invention provides a method for preparing a curved honeycomb sandwich structure light shield, wherein the curved sandwich structure is a honeycomb sandwich structure with a composite material skin, the sandwich structure is a cover, a cylindrical section, a compartment section, or a similar circumferentially closed structure, the structure includes an inner skin and an outer skin, the skin is a composite material, the middle is a honeycomb structure, and multiple embedded parts can be present in the sandwich structure, including the following steps:

[0046] Step S1: Manufacture the inner skin, outer skin, honeycomb core, embedded parts, and other components of the light shield.

[0047] Step S2: Process the sunshade according to its shape, divide the outer skin into multiple petals, pre-assemble the inner skin, outer skin, honeycomb core and embedded parts, and adjust the assembly gap.

[0048] Step S3: Perform surface treatment on the inner skin, outer skin, honeycomb core and embedded parts;

[0049] Step S4: First, apply adhesive film to the inner and outer skins, glue the inner skin onto the mold, then assemble the honeycomb core and embedded parts in sequence, wrap the embedded parts with expanding foam for assembly, and finally assemble the outer skin in sections to form an integral sandwich structure.

[0050] Step S5: Make a vacuum bag. The entire sandwich structure is preheated and vacuumed along with the mold.

[0051] Step S6: Perform local pressure equalization and flow diversion treatment on the irregular curved surface, and remake the vacuum bag;

[0052] Step S7: Perform heat and pressure curing treatment on the entire sandwich structure;

[0053] Step S8: Reinforce the seam where the outer skin is split on the outside.

[0054] Step S9: Demolding yields a light shield with an irregular curved honeycomb sandwich structure.

[0055] In step S1, both the inner and outer skins are formed using a positive mold. During layup, the layup angle trajectory of the composite material is first simulated on the mold, and the layup is performed according to the trajectory to ensure the accuracy of the irregular curved surface angle layup.

[0056] In step S2, the inner skin is a whole and not segmented, while the outer skin is segmented and overlapped according to the structural characteristics of the product. The outer skin is divided along the length of the light shield on its plane.

[0057] In step S2, the inner skin is provided with positioning lugs, which have pin holes and upper and lower waist-shaped holes. Each segment of the outer skin has left and right waist-shaped holes at its upper and lower edges, and upper and lower waist-shaped holes at its center. Positioning lugs are left on the mold during inner skin molding. One of the positioning lugs has a pin hole for repositioning the skin, and the other has upper and lower waist-shaped holes to allow the mold expansion positioning shaft to move during high-temperature curing, preventing bulging caused by localized jamming and thermal stress concentration. The outer skin has left and right waist-shaped holes at the upper and lower edges of each segment, and upper and lower waist-shaped holes near the center. This ensures unidirectional outward expansion of the skin during high-temperature curing, guaranteeing the fit between the skin and the sandwich structure.

[0058] In step S4, the mold to which the inner skin is assembled shares the same core mold 1 with the molding mold of the inner skin, ensuring that the inner skin and the mold have a good fit when the sandwich structure is cured, and ensuring the matching of the surface accuracy.

[0059] In step S5, after the overall sandwich structure is assembled, the product is made into a vacuum bag and heated to 65℃~80℃ along with the mold. A vacuum is then drawn, with the vacuum degree not lower than -0.055Mpa. While drawing the vacuum, the skin and honeycomb are shaped to ensure that the skin and honeycomb fit the mold.

[0060] In step S6, pressure equalization plates 4 are placed locally at locations with large curvature or significant curvature changes on the irregular curved surface to equalize the pressure at these irregular locations. The pressure equalization plates 4 extend 50-60mm outwards on one side at the transition point between the edge and the plane. The pressure equalization plates 4 are deformable plates with certain rigidity and strength; they can be thin metal plates or thin composite material plates, with thin aluminum plates being a suitable material. A flow guide net 5 is placed on the outer side of the pressure equalization plates 4 to guide the local gas flow.

[0061] In step S7, the pressure curing molding process includes, but is not limited to, oven curing molding process, autoclave curing molding process, and vacuum bag pressure curing molding process.

[0062] In step S8, a narrow strip of the same material as the skin is used to reinforce the outer side of the outer skin segment. The width of the reinforcement is preferably increased by 15-25 mm from the center of the seam to both sides.

[0063] This application achieves a lightweight and efficient structure by ensuring the continuity of the fiber structure with good rigidity and strength by not segmenting the inner skin as a whole. It solves the problems of increased weight caused by the need for reinforcement and foam filling at the segmentation position during segmented molding, reduced new interfaces, and the need to shorten the honeycomb height at the segmentation position due to internal reinforcement, which requires splicing of the honeycomb and reduces the strength compared to continuous honeycomb.

[0064] This application uses the same mold for the inner skin of the sandwich structure and the adhesive assembly mold of the sandwich structure to reduce the number of molds and the problem of poor surface matching caused by different molds, and also ensures the fit between the skin surface and the mold under high temperature curing.

[0065] This application improves molding accuracy through the design of skin reset and positioning, solves the problem of high-precision skin reset during sandwich structure molding, and also restricts unidirectional movement when the skin extends, thus solving the problem of disordered slippage during skin extension.

[0066] This application solves problems such as skin not fitting properly to the mold due to the coefficient of thermal expansion at room temperature and high temperature, uneven pressure at different curvature positions during sandwich structure molding, wrinkles or depressions and bulges that prevent the skin from stretching, by introducing preheating treatment, local pressure equalization and flow guiding treatment.

[0067] This application can improve production efficiency and product bonding quality, especially providing good guidance for bonding sandwich structures with irregular curved surfaces, which can greatly improve the manufacturing precision and stability of the products. It enables efficient molding, resulting in products with high precision, excellent performance, good quality consistency, and lightweight, high-strength structures.

[0068] This application does not impose any particular restrictions on the specific shape of the irregular curved honeycomb sandwich structure light shield; it can be designed according to needs. This application uses... Figure 1 Taking the shape as an example, it is a camera lens hood with a honeycomb sandwich structure of composite material skin with different contour tapered curved surfaces. The thickness of the inner and outer skins is 0.5mm, the height of the honeycomb sandwich structure is 6mm, the skin material is T800 / cyanate ester composite material, the honeycomb core is a 5×0.03 porous durable honeycomb, and the adhesive film and foam used are cyanate ester materials. The manufacturing method includes the following steps:

[0069] Step S1: The inner skin is prepared using a bonding assembly mold, and the outer skin is prepared using an outer skin forming mold. During molding, positioning lugs are pre-reserved at the upper and lower ends. Pin holes are pre-reserved at selected locations in the middle of the skin. During layup, lines are first etched on the upper and lower edge generatrices of the reference mold. Using the smaller end generatrice line as a reference, ±45° lines are drawn. Starting from this, spiral winding is used to simulate the layup trajectory of the ±45° layer on the mold, serving as the positioning basis for subsequent layups. A layup diagram is shown below. Figure 2 As shown. Both the honeycomb core and embedded parts are machined.

[0070] Step S2: Pre-assemble the sandwich structure parts. Drill holes on the skin according to the positions of the embedded parts and corresponding holes. Machin the product shape, with positioning lugs on the edges. Leave rounded corners at the connection points with the product. Machin the oblong holes inside the lugs. The inner skin is not segmented. The outer skin is segmented along the length of the cover at a suitable position on the plane. Control the cutting seam to avoid excessive glue gaps. Record the position of each segment. Adapt the position of the embedded parts and control the glue gaps. During the pre-assembly of the honeycomb, if the honeycomb does not fit, it needs to be reshaped to ensure fit. Use tooling strips to limit the outer side. Positioning lugs and positioning strip holes are as follows... Figure 3 As shown.

[0071] Step S3: Perform surface treatment on the carbon fiber skin by grinding and cleaning, clean the honeycomb core, and perform corresponding surface treatment on the other embedded parts.

[0072] Step S4: Apply adhesive film to the bonding surfaces of the inner and outer skins, and wrap the embedded parts with expanding foam. Assemble the inner skin onto the mold, then assemble the honeycomb core. Cut the honeycomb core at the embedded part location, assemble the embedded part, and position it using tooling. The embedded part should not protrude above the honeycomb. Fill the honeycomb core at the edge of the embedded part with expanding foam. Install the outer skin according to the recorded segment positions of the outer skin, without removing the release paper of the adhesive film. Create a vacuum bag on the outside of the cover, evacuate, and maintain the vacuum for a period of time to ensure that the honeycomb and adhesive film are completely compacted and pressed together. Then assemble the outer skin. When assembling the outer skin, the positioning holes of the outer skin are as follows... Figure 4 As shown. The irregular area is first bonded to the honeycomb. With the irregular area as the center, the planar area extends to both sides along the profile so that it is bonded to the honeycomb. The positioning pin is positioned by the ear piece and the inner skin mold.

[0073] Step S5: Fabricate the vacuum bag as a whole. When making the bag, add more breathable material 6 to the corners of the mold to prevent damage to the sealed bag. After the vacuum bag is made, connect the vacuum for a certain period of time. Check the fit of the outer skin under vacuum to prevent slippage and overlap. Connect a thermocouple to the mold and heat the assembly structure and the mold as a whole into the furnace to 65℃~80℃, and then evacuate the vacuum to a level not lower than -0.055Mpa. While evacuating the vacuum, shape the skin and honeycomb to ensure the fit of the skin and honeycomb with the core mold 1.

[0074] Step S6: After vacuum insulation for 1-2 hours, remove the vacuum bag and remake the bag, laying the auxiliary layer as follows. Figure 5 As shown. Product 2 is positioned on core mold 1, and its surface is isolated by isolation film 3. A suitable pressure equalizing plate 4 is placed locally at the irregular curved surface position. The pressure equalizing plate 4 is circumferentially extended outward by 50-60mm on one side at the transition position between the edge and the plane. A guide net 5 is placed on the outside of the pressure equalizing plate 4, and the surface and edges are made of breathable material. The whole is made into a second vacuum bag 7, and the edges are sealed with sealing strips 8. Vacuum is then drawn.

[0075] Step S7: Connect the assembly structure and mold to a thermocouple, perform vacuum leak testing, and then heat and pressurize them for curing. After curing, when the temperature drops to about 80°C, remove the retaining strip and positioning screws, and allow the product to cool to room temperature on the mold.

[0076] Step S8: The outer seam of the product's outer skin is reinforced with a narrow strip of the same material as the skin. The width of the reinforcement is increased by 15-25mm from the center of the seam to both sides.

[0077] Step S9: Demold and clean the product, perform non-destructive testing and dimensional inspection to confirm that it meets the design requirements.

[0078] The method of this application can ensure high-precision, high-strength, lightweight, and low-cost molding of composite curved sandwich structures. It requires fewer molds, thus reducing molding costs. The inner skin has a high degree of fit with the mold, the inner skin is continuous as a whole, and the inner cavity has a complete contour, which has good precision and ensures the strength of the structure. At the same time, it reduces the splicing seams of the honeycomb core due to the skin segmentation and the filling of foam, thus obtaining a lightweight and efficient sandwich structure, and the weight reduction effect of the sunshade is obvious.

[0079] Example 2

[0080] The irregular curved honeycomb sandwich structure light shield provided by the present invention is prepared by the preparation method of the irregular curved honeycomb sandwich structure light shield of Example 1. The obtained irregular curved honeycomb sandwich structure light shield has the advantages of being lightweight, having stable performance, high precision, high rigidity and high strength.

[0081] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0082] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for preparing a light shield with an irregular curved honeycomb sandwich structure, characterized in that, The steps include the following: Step S1: The inner skin, outer skin, honeycomb core, and embedded parts of the light shield are manufactured respectively. Step S2: Process the outer skin according to its shape, divide the outer skin into multiple segments, pre-assemble the inner skin, the outer skin, the honeycomb core and the embedded parts, and adjust the assembly gap. Step S3: Perform surface treatment on the inner skin, the outer skin, the honeycomb core, and the embedded parts; Step S4: First, the inner skin is assembled onto the mold, then the honeycomb core and the embedded parts are assembled in sequence, and finally the outer skin is assembled by overlapping segments to form an integral sandwich structure. Step S5: Make a vacuum bag, preheat and vacuum it; Step S6: Perform local pressure equalization and flow diversion treatment on the irregular curved surface, and remake the vacuum bag; Step S7: Perform heat and pressure curing treatment; Step S8: Reinforce the seam of the outer side of the outer skin. Step S9: Demolding yields a light shield with an irregular curved honeycomb sandwich structure; In step S2, the outer skin is segmented by overlapping segments, and the outer skin is divided along the length of the light shield on its plane. In step S2, the inner skin is provided with positioning ear pieces, and the positioning ear pieces are provided with pin holes and upper and lower waist-shaped holes. Each segment of the outer skin has left and right waist-shaped holes at its upper and lower edges, and upper and lower waist-shaped holes at its middle position.

2. The method for preparing the irregular curved honeycomb sandwich structure light shield as described in claim 1, characterized in that, In step S1, both the inner skin and the outer skin are formed using a positive mold. During layup, the layup angle trajectory of the composite material is first simulated on the mold, and the layers are laid up according to the trajectory.

3. The method for preparing the irregular curved honeycomb sandwich structure light shield as described in claim 1, characterized in that, In step S4, the mold to which the inner skin is assembled shares the same core mold (1) with the molding mold of the inner skin.

4. The method for preparing the irregular curved honeycomb sandwich structure light shield as described in claim 1, characterized in that, In step S5, the integral sandwich structure is heated to 65℃~80℃ along with the mold in a furnace, and a vacuum is drawn with a vacuum degree not lower than -0.055Mpa.

5. The method for preparing the irregular curved honeycomb sandwich structure light shield as described in claim 1, characterized in that, In step S6, pressure is equalized by placing a pressure equalization plate (4). The pressure equalization plate (4) is circumferentially expanded outward by 50-60mm on one side at the transition position between the edge and the plane. The pressure equalization plate (4) includes a thin metal plate and a composite material plate. The flow is guided by placing a flow guide net (5) on the outside of the equalizing plate (4).

6. The method for preparing the irregular curved honeycomb sandwich structure light shield as described in claim 1, characterized in that, In step S7, the pressure curing molding process includes oven curing molding process, autoclave curing molding process, and vacuum bag pressure curing molding process.

7. The method for preparing the irregular curved honeycomb sandwich structure light shield as described in claim 1, characterized in that, In step S8, the outer skin is reinforced at the split position with narrow strips of the same material, and the width of the reinforcement is increased by 15-25mm from the center of the seam to both sides.

8. A light shield with an irregular curved honeycomb sandwich structure, characterized in that, It is prepared by the method of any one of claims 1-7 for the preparation of the irregular curved honeycomb sandwich structure light shield.

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