Thin-wall special-shaped light shield as well as preparation method and mold thereof

Abstract

The invention relates to the technical field of composite materials, in particular to a thin-wall special-shaped light shield and a preparation method and mold thereof, the mold is used for preparing the thin-wall special-shaped light shield, and the thin-wall special-shaped light shield comprises a light shield body and external ribs which are integrally formed; the mold comprises a main body mold part, an end face mold part and an external rib mold part, and the main body mold part is detachably fixed to the first surface of the end face mold part; when the mold is in a mold closing state, the positioning part is arranged in the positioning groove so that the external rib mold part can be positioned on the outer side of the main body mold part, the positioning part can move in the positioning groove in the stress direction of the external rib mold part, a forming groove is formed in the side face, facing the main body mold part, of the external rib mold part, and the forming groove is used for forming an external rib; and the outer side surface of the main body mold part is used for forming a light shield main body. The thin-wall special-shaped light shield with better performance can be prepared at least favorably.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a thin-walled special-shaped sunshade and a preparation method and a mold thereof. Background Art

[0002] Carbon fiber is a fibrous carbon material with an incomplete graphite crystallization and a carbon content of more than 90%. Carbon fiber-resin matrix composite materials are resin matrix composite materials with carbon or graphite fibers as reinforcements. At present, due to the superior specific strength and specific stiffness of carbon fiber composite materials, carbon fiber composite materials are increasingly used in the manufacture of space optical structures, for example, in the manufacture of optical platforms, precision instrument support structures, space telescope brackets or sunshades, etc.

[0003] In the structure of space cameras, the sun hood, as an important component of the optical system, is mostly placed at the front end of the optical system to reduce the external stray light entering the optical system, thereby preventing the stray light from affecting the imaging quality of the optical system.

[0004] Since the lens hood is located at the front end of the optical system and far away from the end of the overall structure of the optical system, the lens hood often produces a large structural response to the optical system. In other words, the lens hood has a great influence on the overall structural stability of the optical system. Therefore, the lens hood needs to have a light weight as much as possible. At the same time, the lens hood also needs to have a certain rigidity to meet the requirements of its performance. Therefore, carbon fiber composite materials can be used to prepare thinner lens hoods to meet the strength and weight requirements of the lens hood at the same time. In the design process of the lens hood, the structural rigidity of the lens hood can be further improved by using built-in apertures or adding reinforcement ribs. However, most of the complex special-shaped lens hood reinforcement ribs are currently assembled on the lens hood shell by threaded connection and adhesive connection. This not only makes the preparation cost of the lens hood high, but also makes the preparation steps more, and the weight of the lens hood cannot be further reduced due to the presence of connecting parts such as bolts or screws. Therefore, the preparation method of the lens hood with reinforcement ribs needs to be improved. Summary of the invention

[0005] In view of this, the present invention aims to provide a thin-walled special-shaped sunshade and a preparation method and a mold thereof, which are conducive to preparing a thin-walled special-shaped sunshade with better performance.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: The invention provides a mold for preparing a thin-walled special-shaped sunshade, the thin-walled special-shaped sunshade comprising: an integrally formed sunshade body and an external rib, the external rib being located on the outer surface of the sunshade body, the sunshade body having a first end and a second end opposite to each other, the external rib extending in a direction from the first end to the second end; the mold comprising: a main body mold portion, an end face mold portion and an external rib mold portion, the end face mold portion having a first surface, the main body mold portion being detachably fixed to the first surface of the end face mold portion, the first surface also having a positioning groove, the external rib mold portion comprising a main body portion and a positioning portion connected thereto; when the mold is in a mold closing state, the positioning portion is arranged in the positioning groove so that the external rib mold portion is positioned on the outside of the main body mold portion, and the positioning portion is movable in the positioning groove along the force direction of the external rib mold portion, the external rib mold portion having a molding groove on the side of the external rib mold portion facing the main body mold portion, the molding groove being used to form the external rib, and the outer side surface of the main body mold portion being used to form the sunshade body, wherein the force direction of the external rib mold portion is the direction from the external rib mold portion to the main body mold portion.

[0007] Furthermore, a plurality of external ribs are arranged at intervals on the outer surface of the sunshade body; the mold includes a plurality of external rib mold parts, and when the mold is in a closed mold state, each external rib mold part is positioned on the outside of the main mold part through a corresponding positioning groove, and an external rib mold part has at least one molding groove, and the force direction of the external rib mold part is: the corresponding external rib mold part points in the direction of the main mold part.

[0008] Furthermore, the main body has a pressing surface and a pressure-bearing surface that are relatively arranged. When the mold is in a closed mold state, the pressing surface is the side of the external rib mold part facing the main mold part, and the molding groove is located on the pressing surface; the pressure-bearing surface is a plane, and the pressure-bearing surface is perpendicular to the force direction of the external rib mold part.

[0009] Further, the material of the rib die portion includes aluminum alloy, and the material of the main die portion and / or the material of the end face die portion includes steel.

[0010] Furthermore, the main mold part is a hollow structure, the hood body has an opening, and the opening extends from the second end to the first end; the outer side surface of the main mold part has an opening area corresponding to the opening, and the hood body is formed on the outer side surface of the main mold part outside the opening area.

[0011] Furthermore, the thin-walled special-shaped sunshade further includes: a flange, the flange is connected to the first end, and a portion of the first surface adjacent to the main body mold portion is used to form the flange.

[0012] On the other hand, the present invention provides a method for preparing a thin-walled special-shaped sunshade, comprising: providing the above-mentioned mold, the mold comprising a main body mold part, an end face mold part and an external rib mold part; laying a first prepreg composite layer on the outer side surface of the main body mold part as a skin, the skin is used to form the sunshade body; laying a first prepreg composite layer in the molding groove of the external rib mold part as an initial external rib, the initial external rib is used to form the external rib; positioning the external rib mold part on the outside of the main body mold part through the positioning groove, and closing the mold; arranging a vacuum bag outside the closed mold, evacuating the vacuum bag, and performing a first heating and pressurizing curing process on the mold with the vacuum bag using an autoclave; demolding the mold after cooling to obtain a thin-walled special-shaped sunshade, the thin-walled special-shaped sunshade comprising an integrally formed sunshade body and external ribs.

[0013] Furthermore, the first prepreg composite layer includes multiple base layers, and the ply parameter of the first prepreg composite layer is [0 / 90]ns, wherein n is an integer obtained by dividing the thickness of the sunshade body by twice the thickness of the base layer. The process of laying the first prepreg composite layer includes: vacuuming and pre-compacting the base layer.

[0014] Furthermore, the sunshade body has an opening, and the opening extends from the second end of the sunshade body to the first end of the sunshade body; the preparation method also includes: obtaining an initial thin-walled special-shaped sunshade through a first temperature increase and pressurization curing process, and compensating for deformation of the initial thin-walled special-shaped sunshade, the deformation compensation including: after the mold is cooled to room temperature, before the demolding step, laying a second prepreg composite layer on the outer side of the second end other than the opening, the width of the second prepreg composite layer is in the range of 20mm~25mm, and the second prepreg composite layer is a unidirectional layer; high-temperature curing treatment is performed on the initial thin-walled special-shaped sunshade laid with the second prepreg composite layer, and demolding is performed after the mold is cooled to obtain a thin-walled special-shaped sunshade.

[0015] On the other hand, the present invention also provides a thin-walled special-shaped light shield, which is prepared using the above-mentioned mold, or prepared using the above-mentioned method for preparing a thin-walled special-shaped light shield, and the thin-walled special-shaped light shield includes: an integrally formed light shield body and external ribs, the light shield body is a cylindrical structure, the light shield body has a first end and a second end opposite to each other, the external ribs are located on the outer side of the light shield body, and the external ribs extend in the direction from the first end to the second end.

[0016] Compared with the prior art, the invention can achieve the following beneficial effects: the invention provides a mold, which can be used to prepare an integrally formed thin-walled special-shaped sunshade. Specifically, the mold includes: a main body mold part, an end face mold part and an external rib mold part. Prepreg for forming the sunshade body is laid on the outer side of the main body mold part, and prepreg for forming the external rib is laid in the molding groove of the external rib mold part. The positioning part of the external rib mold part cooperates with the positioning groove of the end face mold part to position the external rib mold part on the outside of the main body mold part, and the mold is closed. In this way, the external rib mold part is used to form the external rib. The prepreg is positioned on the outer surface of the prepreg used to form the main body of the sunshade, and pressure is applied in the direction of the external rib mold portion pointing to the main body mold portion. The prepreg is then cured at high temperature and high pressure to form a thin-walled special-shaped sunshade in which the external ribs and the sunshade main body are integrally formed. Compared with the method of assembling the reinforcing ribs on the sunshade shell by bolting or screwing and gluing, the weight of the thin-walled special-shaped sunshade with external ribs is reduced, the preparation steps of the thin-walled special-shaped sunshade with external ribs are reduced, the preparation difficulty of the thin-walled special-shaped sunshade is reduced, and a thin-walled special-shaped sunshade with better performance can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 It is a structural schematic diagram of a mold provided with a thin-walled special-shaped light shield according to an embodiment of the present invention when it is in a mold closing state; Figure 2 A schematic diagram of the exploded structure of the mold according to an embodiment of the present invention; Figure 3 The present invention is a schematic structural diagram of a thin-walled special-shaped sunshade according to an embodiment of the present invention.

[0018] Explanation of the reference numerals: 100, thin-walled special-shaped sunshade; 101, first end; 102, second end; 110, sunshade body; 111, external rib; 112, opening; 113, flange; 200, main body mold portion; 201, first end portion; 202, second end portion; 203, opening area; 204, hollow; 210, end face mold portion; 211, positioning groove; 212, first surface; 220, external rib mold portion; 221, main body; 222, positioning portion; 223, pressure-bearing surface. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0020] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0021] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0022] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0023] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0024] like Figures 1 to 3As shown, the invention provides a mold for preparing a thin-walled special-shaped sunshade 100, and the thin-walled special-shaped sunshade 100 includes: an integrally formed sunshade body 110 and an external rib 111, the external rib 111 is located on the outer surface of the sunshade body 110, the sunshade body 110 has a first end 101 and a second end 102 relative to each other, the external rib 111 extends from the first end 101 to the second end 102, the sunshade body 110 is a tubular structure, and in the direction from the first end 101 to the second end 102, the inner circumference of the tubular structure gradually increases, or in other words, the outer shape of the tubular structure gradually increases.

[0025] It should be noted that the mold provided by the invention must meet the following requirements: the mold can be used to form a thin-walled special-shaped sunshade 100 with a sunshade main body 110 and external ribs 111 integrally formed, and the mold is an autoclave pressurized molding mold. The autoclave pressurized molding mold refers to a mold on which prepreg is laid, which can cure the prepreg at high temperature and high pressure by means of autoclave pressurization, thereby preparing a corresponding product.

[0026] The mold provided by the invention comprises: a main mold part 200, an end mold part 210 and an external rib mold part 220, the end mold part 210 has a first surface 212, the main mold part 200 is detachably fixed to the first surface 212 of the end mold part 210, the first surface 212 also has a positioning groove 211, and the external rib mold part 220 comprises a main part 221 and a positioning part 222 connected to each other; when the mold is in a mold-closing state, the positioning part 222 is arranged in the positioning groove 211 so that the external rib mold part The rib mold portion 220 is positioned on the outside of the main mold portion 200, and the positioning portion 222 is movable in the positioning groove 211 along the force direction of the external rib mold portion 220, and the external rib mold portion 220 has a molding groove (not shown) on the side facing the main mold portion 200, and the molding groove is used to form the external rib 111, and the outer side surface of the main mold portion 200 is used to form the sunshade body 110, wherein the force direction of the external rib mold portion 220 is the direction in which the external rib mold portion 220 points to the main mold portion 200.

[0027] Among them, the main mold part 200 can be detachably fixed to the first surface 212 of the end face mold part 210. In this way, when demolding, the main mold part 200 can be removed from the end face mold part 210, which facilitates the demolding of the product. It should be noted that the products involved in the embodiments of the invention are all thin-walled special-shaped sunshades 100.

[0028] In some embodiments of the present invention, the end face mold portion 210 has a first surface 212 and a second surface opposite to each other, and the positioning groove 211 may extend from the first surface 212 to the second surface. In some examples, the positioning groove 211 may be a through groove that penetrates the end face mold portion 210 along the thickness direction of the end face mold portion 210; in other examples, the positioning groove 211 may not penetrate the end face mold portion 210.

[0029] The positioning portion 222 is movable in the positioning groove 211 along the force direction of the external ribbed mold portion 220 to reserve pressurized moving space for the external ribbed mold portion 220 and avoid the positioning groove 211 limiting the external ribbed mold portion 220 when the external ribbed mold portion 220 is used to pressurize the prepreg.

[0030] In some embodiments of the present invention, along a direction perpendicular to the first surface 212, the end of the main mold portion 200 where the end face mold portion 210 is fixed is a first end portion 201, and the end of the main mold portion 200 away from the end face mold portion 210 is a second end portion 202. Along the direction from the first end portion 201 to the second end portion 202, the outer shape of the main mold portion 200 gradually increases so as to be suitable for forming a thin-walled special-shaped sunshade.

[0031] In some embodiments of the present invention, when the mold is in a mold-closing state, along the direction from the first end 201 to the second end 202, the shape of the main body 221 of the external rib mold part 220 gradually becomes smaller, and the orthographic projection of the main body 221 on the first surface 212 covers the orthographic projection of the positioning portion 222 on the first surface 212, the positioning portion 222 is provided at the bottom end of the main body 221, and the bottom end of the main body 221 is also provided with a bottom surface that can contact the first surface 212, and the bottom surface of the main body 221 can be completely Fully or partially covering the positioning groove 211 is beneficial to improving the stability of the external rib mold part 220 positioned on the end face mold part 210, and ensuring that when the external rib mold part 220 slides under force, the external rib mold part 220 can move toward the main mold part 200, avoiding the external rib mold part 220 from tilting toward the main mold part 200 when subjected to force, which is beneficial to ensuring that after pressurization, the prepreg laid in the external rib mold part 220 is in close contact with the prepreg laid on the outer surface of the main mold part 200.

[0032] It should be noted that the contact area between the bottom surface of the main body 221 and the first surface 212 cannot be too large, which is helpful to reduce friction and facilitate the movement of the rib mold part 220 toward the main body mold part 200 during the pressurization process.

[0033] Furthermore, multiple external ribs 111 are arranged at intervals on the outer surface of the sunshade body 110; the mold includes multiple external rib mold parts 220, and when the mold is in a closed mold state, each external rib mold part 220 is positioned on the outside of the main mold part 200 through a corresponding positioning groove 211, and an external rib mold part 220 has at least one molding groove.

[0034] Furthermore, the main body 221 has a pressing surface and a pressure-bearing surface 223 that are arranged opposite to each other. When the mold is in the mold-closing state, the pressing surface is the side of the external rib mold part 220 facing the main mold part 200, the molding groove is located on the pressing surface, and the shape of the pressing surface corresponds to the shape of the corresponding external side surface of the main mold part 200; the pressure-bearing surface 223 is a plane, and the pressure-bearing surface 223 is perpendicular to the force direction of the external rib mold part 220. In other words, the external side surface of the external rib mold part 220 is a plane, and during the pressurization process, the pressure on the external rib mold part 220 is in the direction from the external rib mold part 220 to the main mold part 200, thereby ensuring that the prepreg laid in the external rib mold part 220 is in close contact with the prepreg laid on the outer surface of the main mold part 200.

[0035] Further, the material of the ribbed mold part 220 includes aluminum alloy, and the material of the main mold part 200 and / or the material of the end mold part 210 includes steel. Using aluminum alloy to manufacture the ribbed mold part 220 is conducive to reducing the weight of the ribbed mold part 220, and facilitating the movement of the ribbed mold part 220 toward the main mold part 200 during the pressurization process; using steel as the material of the main mold part 200 and / or the end mold part 210 is conducive to ensuring that the main mold part 200 and / or the end mold part 210 can provide sufficient rigidity support.

[0036] Furthermore, the main mold part 200 is a hollow structure, which is conducive to reducing the weight of the main mold part 200, and during the high-temperature curing process, heat can be quickly diffused from the hollow 204 to the prepreg, so as to better perform high-temperature curing on the prepreg. Figure 1 and Figure 3 The hood body 110 has an opening 112 extending from the second end 102 to the first end 101 ; the outer side surface of the main mold portion 200 has an opening area 203 corresponding to the opening 112 , and the hood body 110 is formed on the outer side surface of the main mold portion 200 outside the opening area 203 .

[0037] Furthermore, the thin-walled special-shaped sunshade 100 further includes a flange 113 , which is connected to the first end 101 of the sunshade body 110 , and a portion of the first surface 212 adjacent to the main body mold portion 200 is used to form the flange 113 .

[0038] Another aspect of the present invention provides a method for preparing a thin-walled special-shaped sunshade 100, comprising: refer to Figures 1 to 3 , providing the above-mentioned mold, the mold includes a main mold part 200, an end surface mold part 210 and an external rib mold part 220, and using the mold to form a thin-walled special-shaped sunshade 100. The preparation steps after providing the mold are as follows: First, a first prepreg composite layer is laid on the outer side of the main mold part 200 as a skin, and the skin is used to form the sunshade body 110. The first prepreg composite layer is the prepreg used to form the sunshade body 110. The first prepreg composite layer is laid in the molding groove of the external rib mold part 220 as an initial external rib, and the initial external rib is used to form the external rib 111. That is, the same prepreg can be used to form the sunshade body 110 and the external rib 111.

[0039] Furthermore, the first prepreg composite layer includes a plurality of base layers, and the ply parameter of the first prepreg composite layer is [0 / 90]ns, wherein n is an integer obtained by dividing the thickness of the sunshade body by twice the thickness of the base layer, and the process of laying the first prepreg composite layer includes: vacuuming and pre-compacting the base layer. The vacuuming and pre-compacting refers to pressurizing the prepreg by means of the negative pressure formed by vacuuming between the corresponding vacuum bag and the mold.

[0040] In some embodiments of the present invention, the base layer may be a single-layer prepreg composed of carbon fiber and resin.

[0041] For the first prepreg composite layer, the extending direction of the fibers in the base layer closest to the mold is parallel to the direction pointing to the second end 102 from the first end 101 .

[0042] The reason for selecting [0 / 90]ns as the layup parameter of the first prepreg composite layer is that due to the irregular structure of the thin-walled special-shaped sunshade, the stress generated by the different thermal expansion coefficients of the fiber and the resin during the subsequent curing process will further aggravate the deformation of the thin-walled special-shaped sunshade. Therefore, the orthogonal symmetrical layup with a layup parameter of [0 / 90]ns is adopted, which is beneficial to reduce the coupling effect caused by the curing of the first prepreg composite layer and alleviate the deformation of the special-shaped sunshade.

[0043] In some embodiments of the present invention, vacuum pre-compaction may be performed once after laying each base layer; in other embodiments of the present invention, vacuum pre-compaction may also be performed once after laying two or three base layers. In other words, the embodiments created by the present invention do not limit the number and timing of vacuum pre-compaction during the process of laying the first prepreg composite layer.

[0044] After laying the first prepreg composite layer, the rib mold part 220 is positioned outside the main mold part 200 through the positioning groove 211, and the mold is closed. In this way, the initial ribs laid in the molding groove of the rib mold part 220 can be positioned on the outer surface of the skin, and then the co-curing molding of the ribs 111 and the sunshade main body 110 can be achieved later.

[0045] After the mold is closed, a vacuum bag is arranged outside the mold. The vacuum bag can be evacuated by a vacuum pumping device in the autoclave to make the initial external rib fit with the skin.

[0046] After pre-compacting, the mold covered with a vacuum bag is subjected to a first temperature-raising and pressurizing curing process using an autoclave. It should be noted that both the pre-compacting and the first temperature-raising and pressurizing curing process can be achieved using an autoclave.

[0047] Specifically, the first temperature rise and pressurization curing process includes: using a thermocouple of the autoclave to monitor the temperature of the mold, and pressurizing when the temperature reaches 50°C. The pressurized gas pressure can be in the range of 0.2MPa~0.3MPa. After the temperature reaches 100°C, it is maintained for 3 hours. After the temperature reaches 150°C, it is maintained for 7 hours, and then the temperature is lowered. The process is always in a pressurized state until it cools to 50°C and the pressurization is stopped.

[0048] After heating and pressurizing, the mold is cooled to room temperature and then demolded to obtain an initial thin-walled special-shaped light shield, which can be directly used as a thin-walled special-shaped light shield 100 . The thin-walled special-shaped light shield 100 includes an integrally formed light shield body 110 and external ribs 111 .

[0049] Furthermore, the sunshade body 110 has an opening 112, and the opening 112 extends from the second end 102 of the sunshade body 110 to the first end 101 of the sunshade body 110; the preparation method also includes: performing deformation compensation on the initial thin-walled special-shaped sunshade, and the deformation compensation includes: after the mold is cooled to room temperature, before demolding, laying a second prepreg composite layer on the outer side of the second end 102 outside the opening 112, and before demolding, the width of the second prepreg composite layer is in the range of 20mm~25mm, and the second prepreg composite layer is a unidirectional layer; high-temperature curing treatment is performed on the initial thin-walled special-shaped sunshade laid with the second prepreg composite layer, and demolding is performed after the mold is cooled to obtain a thin-walled special-shaped sunshade 100.

[0050] That is to say, after the first temperature-raising and pressurizing curing process, the mold can be taken out of the autoclave after the mold is cooled to room temperature to perform deformation compensation.

[0051] The reason for deformation compensation is that during the curing process of the first prepreg composite layer, there will be certain stress due to the different thermal expansion coefficients of the fiber and the resin, and the thin-walled special-shaped sunshade 100 involved in the present invention has an opening 112, which is a sudden change structure. Therefore, the edge stiffness of the second end 102 is weak and it is easy to deform, which is mostly manifested as a reduction in the opening 112. If the deformation is compensated by mold design, it is easy to cause other related dimensional changes and the controllability is poor. Therefore, the embodiment of the present invention adopts deformation compensation after curing.

[0052] A second prepreg composite layer is laid on the outer surface of the second end 102 of the hood body 110. The second prepreg composite layer will shrink during the high temperature and high pressure curing process. Since the second prepreg composite layer is not set at the edge of the opening 112, the shrunk second prepreg composite layer pulls the edge of the second end 102 of the hood body 110 outward, thereby enlarging the opening 112 to suppress the shrinkage of the opening 112 caused by the first temperature increase and pressure curing process.

[0053] It should be noted that the second prepreg composite layer is a unidirectional layer, that is, the layering parameter of the second prepreg composite layer is [0]n, and the base layer material of the second prepreg composite layer is the same as that of the first prepreg composite layer.

[0054] The extending direction of the fibers in each base layer of the second prepreg composite layer is the circumferential direction of the edge of the sunshade body.

[0055] The base layers of the second prepreg composite layer and the first prepreg composite layer can both be single-layer prepregs composed of T700 carbon fiber and resin. The principle of deformation compensation can also be as follows: when laying the second prepreg composite layer, the initial thin-walled special-shaped sunshade has not been demolded, so the mold suppresses the shrinkage of the initial thin-walled special-shaped sunshade. It should be noted that when the T700 prepreg is laid with a layer parameter of [0 / 90}ns, its positive thermal expansion coefficient is 2.5×e -6 When T700 prepreg is laid with a ply parameter of [0]n, its positive thermal expansion coefficient is 4.5×e -8 Therefore, the positive thermal expansion coefficient of the second prepreg composite layer is very small, and the shrinkage of the second prepreg composite layer after curing is small, so that the initial thin-walled special-shaped sunshade is maintained in the size state on the mold, and the second prepreg composite layer does not cause additional shrinkage, thereby greatly inhibiting the shrinkage caused by the first prepreg composite layer.

[0056] The shrinkage compensation size can refer to the following formula: △L=L×(a （单向带） -a （产品） )×(t2-t1), where △L is the shrinkage compensation size, L is the length of the second prepreg composite layer, and a （单向带） is the linear thermal expansion coefficient of the second prepreg composite layer, a（产品） is the linear thermal expansion coefficient of the first prepreg composite layer, t2 is the gel temperature of the resin, and t1 is the room temperature.

[0057] In some embodiments of the present invention, after the mold is cooled to room temperature and before demoulding, the cured second prepreg composite layer is polished and trimmed so that it is not obtrusive to the sunshade body 110 .

[0058] On the other hand, the present invention also provides a thin-walled special-shaped sunshade 100. The thin-walled special-shaped sunshade 100 is prepared using the above-mentioned mold, or is prepared using the above-mentioned method for preparing the thin-walled special-shaped sunshade 100. The thin-walled special-shaped sunshade 100 includes: an integrally formed sunshade body 110 and external ribs 111. The sunshade body 110 is a tubular structure. The sunshade body 110 has a first end 101 and a second end 102 opposite to each other. The external ribs 111 are located on the outer side of the sunshade body 110, and the external ribs 111 extend in a direction from the first end 101 to the second end 102. The sunshade body 110 is a tubular structure, and the inner circumference of the tubular structure gradually increases in a direction from the first end 101 to the second end 102.

[0059] Furthermore, a plurality of external ribs 111 are arranged at intervals on the outer surface of the light shield body 110 .

[0060] Furthermore, the light shield body 110 has an opening 112 , and the opening 112 extends from the second end 102 to the first end 101 .

[0061] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0062] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A mold, characterized in that: The mold is used to prepare a thin-walled special-shaped sunshade, and the thin-walled special-shaped sunshade comprises: an integrally formed sunshade body and an external rib, the external rib is located on the outer surface of the sunshade body, the sunshade body has a first end and a second end opposite to each other, and the external rib extends in a direction from the first end to the second end; The mold comprises: a main body mold part, an end face mold part and an external rib mold part, the end face mold part has a first surface, the main body mold part is detachably fixed to the first surface of the end face mold part, the first surface also has a positioning groove, and the external rib mold part comprises a main body part and a positioning part connected to each other; When the mold is in a mold closing state, the positioning portion is arranged in the positioning groove so that the external rib mold portion is positioned on the outside of the main mold portion, and the positioning portion is movable in the positioning groove along the force direction of the external rib mold portion, and the external rib mold portion has a molding groove on the side facing the main mold portion, and the molding groove is used to form the external rib, and the outer side surface of the main mold portion is used to form the sunshade body, wherein the force direction of the external rib mold portion is the direction in which the external rib mold portion points to the main mold portion.

2. The mold according to claim 1, characterized in that: A plurality of the external ribs are arranged at intervals on the outer surface of the sunshade body; The mold includes multiple external rib mold parts. When the mold is in a closed mold state, each of the external rib mold parts is positioned on the outside of the main mold part through the corresponding positioning groove. One of the external rib mold parts has at least one forming groove. The force direction of the external rib mold part is: the corresponding external rib mold part points in the direction of the main mold part.

3. The mold according to claim 1, characterized in that: The main body has a pressing surface and a pressure-bearing surface that are arranged opposite to each other. When the mold is in a mold-closing state, the pressing surface is the side of the external rib mold part facing the main body mold part, and the molding groove is located on the pressing surface; The pressure-bearing surface is a plane, and the pressure-bearing surface is perpendicular to the force direction of the external rib mold part.

4. The mold according to claim 1, characterized in that: The material of the additional rib mold part includes aluminum alloy, and the material of the main body mold part and / or the material of the end surface mold part includes steel.

5. The mold according to claim 1, characterized in that: The main body mold part is a hollow structure, and the light shield body has an opening, and the opening extends from the second end to the first end; The outer side surface of the main body mold portion has an opening area corresponding to the opening, and the outer side surface of the main body mold portion outside the opening area forms the light shield body.

6. The mold according to claim 1, characterized in that: The thin-walled special-shaped light shield further includes a flange, the flange is connected to the first end, and a portion of the first surface adjacent to the main body mold portion is used to form the flange.

7. A method for preparing a thin-walled special-shaped sunshade, characterized in that: include: A mold according to any one of claims 1 to 6 is provided, wherein the mold comprises a main body mold portion, an end face mold portion and an external rib mold portion; Laying a first prepreg composite layer as a skin on the outer side of the main mold portion, wherein the skin is used to form a sunshade body; Laying the first prepreg composite layer in the molding groove of the external rib mold as an initial external rib, wherein the initial external rib is used to form an external rib; Positioning the external rib mold part on the outside of the main mold part through the positioning groove to close the mold; A vacuum bag is arranged outside the mold of the mold closing, the vacuum bag is evacuated, and the mold with the vacuum bag is subjected to a first temperature-raising and pressurizing curing process by using the autoclave; After the mold is cooled, demoulding is performed to obtain a thin-walled special-shaped light shield, wherein the thin-walled special-shaped light shield comprises the light shield body and the external ribs which are integrally formed.

8. The method for preparing a thin-walled special-shaped sunshade according to claim 7, characterized in that: The first prepreg composite layer includes multiple base layers, and the ply parameter of the first prepreg composite layer is [0 / 90]ns, wherein n is an integer obtained by dividing the thickness of the sunshade body by twice the thickness of the base layer. The process of laying the first prepreg composite layer includes: vacuuming and pre-compacting the base layer.

9. The method for preparing a thin-walled special-shaped sunshade according to claim 7 or 8, characterized in that: The shading cover body has an opening, and the opening extends from the second end of the shading cover body to the first end of the shading cover body; The preparation method further includes: obtaining an initial thin-walled special-shaped sunshade through the first temperature-raising and pressurizing curing process, and performing deformation compensation on the initial thin-walled special-shaped sunshade, wherein the deformation compensation includes: after the mold is cooled to room temperature, before performing the demoulding step, laying a second prepreg composite layer on the outer side surface of the second end outside the opening, wherein the width of the second prepreg composite layer is within the range of 20 mm to 25 mm, and the second prepreg composite layer is a unidirectional layer; The initial thin-walled special-shaped sunshade with the second prepreg composite layer is subjected to high-temperature curing treatment, and demoulding is performed after the mold is cooled to obtain the thin-walled special-shaped sunshade.

10. A thin-walled special-shaped sunshade, characterized in that: The thin-walled special-shaped light shield is prepared by using the mold described in any one of claims 1 to 6, or by using the method for preparing a thin-walled special-shaped light shield as described in any one of claims 7 to 9, the thin-walled special-shaped light shield comprises: an integrally formed light shield body and external ribs, the light shield body having a first end and a second end opposite to each other, the external ribs being located on the outer surface of the light shield body, and the external ribs extending in a direction from the first end to the second end.

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