Forming mold and preparation method of composite material structure square tube for satellite

Abstract

The invention discloses a forming mold and a preparation method of a composite material structure square tube for a satellite. The forming mold comprises a core mold and a pressing mold, the core mold is provided with four first molding surfaces which are respectively used for molding four inner walls of the square tube; the pressing die comprises an upper pressing strip and a lower pressing strip, and the lower pressing strip is provided with a second forming face and a third forming face which are used for forming the lower outer wall and the right outer wall of the square pipe respectively. The upper pressing strip is provided with a fourth forming surface and a fifth forming surface which are respectively used for forming the upper outer wall and the left outer wall of the square tube; the first end of the lower pressing strip is in beveled fit with the second end of the upper pressing strip, and the second end of the lower pressing strip is in beveled fit with the first end of the upper pressing strip. The method is applied to the field of composite material forming, the winding and mold pressing coupling technology is applied to preparation of simple structural parts such as satellite structure square pipes, and the method has the advantages of being easy to prepare, low in cost, high in product bearing strength, large in structural rigidity, high in integration degree, good in reliability and the like.

Description

Technical Field

[0001] The invention relates to the technical field of composite material molding, and in particular to a composite material structure square tube molding die for satellites and a preparation method thereof. Background Art

[0002] Satellite square tubes are key load-bearing components used in satellite structures. They provide mounting bases for key components such as satellite payloads, attitude control propulsion systems, and communication antennas. Therefore, satellite square tubes need to withstand large overloads caused by complex mechanical environments during satellite launch, on-orbit maneuvers, and orbit maintenance; withstand thermal stress caused by extreme temperature changes in space to protect internal systems; and must have a certain dimensional stability to ensure the normal operation of sensitive internal equipment.

[0003] Composite materials have excellent properties such as light weight, high specific modulus, high specific strength, shock absorption and heat insulation (low thermal conductivity). Using composite materials to prepare square tubes and other components in satellite structures can achieve lightweight satellite structures, improve their on-orbit maneuverability and fuel efficiency; increase the amount of payload carried and reduce energy consumption; and effectively reduce structural deformation and improve the stability and reliability of internal equipment.

[0004] Composite structural parts in existing satellite structures are generally made using autoclave technology to ensure low porosity and high density. With the advancement of aerospace technology, the launch cycle is further shortened, and the autoclave process has a long manufacturing cycle and high cost, which makes the traditional autoclave process not well matched with aerospace needs. Summary of the invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention provides a composite material structural square tube forming mold and preparation method for satellites, which meet the requirements of satellite structural square tube load-bearing, light weight, and rapid preparation of internal and external contour stable right-angle edge forming, and has the advantages of simple preparation, low cost, high product bearing strength, high structural rigidity, high degree of integration, and good reliability.

[0006] To achieve the above-mentioned purpose, the present invention provides a composite material structure square tube forming die for satellite, comprising a core die and a pressure die; The core mold is a rectangular strip structure having four first molding surfaces, which are respectively used for molding four inner walls of the square tube; The die comprises an upper press strip and a lower press strip, and the cross-sections of the upper press strip and the lower press strip are both L-shaped: The lower pressing strip has a second molding surface and a third molding surface, which are used for molding the lower outer wall and the right outer wall of the square tube respectively; The upper pressure strip has a fourth molding surface and a fifth molding surface, which are used for molding the upper outer wall and the left outer wall of the square tube respectively; The first end of the lower press strip is beveled and matched with the second end of the upper press strip, and the second end of the lower press strip is beveled and matched with the first end of the upper press strip.

[0007] In one embodiment, the first end of the lower press strip is adjacent to the second molding surface, and the second end of the upper press strip is adjacent to the fifth molding surface; A first inclined surface is provided at the first end of the lower pressing strip, and a top end of the first inclined surface is inclined in a direction away from the second forming surface; A second inclined surface is provided at the second end of the upper press strip, and a bottom end of the second inclined surface is inclined toward a direction close to the fifth forming surface; The inclination angles of the first inclined surface and the second inclined surface are both 30° to 60°, and the first inclined surface is beveled to match the second inclined surface.

[0008] In one embodiment, the upper press strip includes a top press strip and a left press strip that are separated, the fourth molding surface is located on the top press strip, and the fifth molding surface is located on the left press strip; The second inclined surface is located at the bottom side of the left press strip, a third inclined surface is provided at the top side of the left press strip, and the top end of the third inclined surface is inclined toward the direction close to the fifth molding surface; A fourth inclined surface is provided at the left end of the top pressure strip, and the bottom end of the fourth inclined surface is inclined in a direction away from the fourth molding surface; The inclination angles of the third inclined surface and the fourth inclined surface are both 30°-60°, and the third inclined surface is bevel-cut and matched with the fourth inclined surface.

[0009] In one embodiment, the second end of the lower press strip is adjacent to the third molding surface, and the first end of the upper press strip is adjacent to the fourth molding surface; A fifth inclined surface is provided at the second end of the lower pressing strip, and the top end of the fifth inclined surface is inclined toward a direction close to the third forming surface; A sixth inclined surface is provided at the first end of the upper press strip, and a bottom end of the sixth inclined surface is inclined in a direction away from the fourth molding surface; The inclination angles of the fifth inclined surface and the sixth inclined surface are both 30°-60°, and the fifth inclined surface is bevel-cut and matched with the sixth inclined surface.

[0010] In one embodiment, the lower press strip includes a separate bottom press strip and a right press strip, the second molding surface is located on the bottom press strip, and the third molding surface is located on the right press strip; The fifth inclined surface is located on the top side of the right bead, and a seventh inclined surface is provided on the bottom side of the right bead, and the bottom end of the seventh inclined surface is inclined toward the direction close to the third molding surface; An eighth inclined surface is provided at the right end of the bottom press strip, and the top end of the eighth inclined surface is inclined in a direction away from the second forming surface; The inclination angles of the seventh inclined surface and the eighth inclined surface are both 30°-60°, and the seventh inclined surface is bevel-cut and matched with the eighth inclined surface.

[0011] To achieve the above object, the present invention also provides a method for preparing a composite material structural square tube for satellites, using the above-mentioned molding die; The preparation method comprises the following steps: Step 1, prepare the resin solution, adjust its viscosity and add it into the roller groove of the winding machine, so that the surface of the carbon fiber yarn is evenly covered with the resin solution to ensure that the carbon fiber yarn is impregnated; Step 2, adjusting the tension of the carbon fiber yarn on the winding machine, starting the winding machine, and winding and laying the core mold according to the layup design; Step 3, remove the wound core mold, place it in the die, and check the degree of mold closing; Step 4, placing the entire mold in a hot press and performing hot pressing curing according to a certain curing system; Step 5, after curing is completed, demoulding and trimming are performed to obtain a composite material structure satellite square tube component.

[0012] In one embodiment, the carbon fiber yarn is a high-performance carbon fiber T700, T800, M40, M55J with a single filament fineness of 3K, 6K or 12K.

[0013] In one embodiment, in step 1, the materials for preparing the resin solution include base resin, curing agent and solvent; The base resin is epoxy 648 resin; The curing agent is boron trifluoride monoethylamine, and the amount used is 1% to 5% of the mass of the base resin; The solvent is acetone, and the amount used is 30% to 60% of the base resin.

[0014] In one of the embodiments, in step 2, during the process of winding and laying the core mold, the laying angles are symmetrically arranged in a certain order according to multiple direction angles of 0°, ±30°, ±45°, and 90°, and the thickness of the layer is 0.2mm~0.4mm.

[0015] In one embodiment, in step 4, the process of hot pressing curing is specifically as follows: Heat the mold from room temperature to 80-100°C in 10-20 minutes, keep it at 80-100°C for 4-6 hours, and apply a pressure of 0.1-0.3MPa to the upper and lower working surfaces of the mold; Raise the temperature from 80~100℃ to 100~160℃ in 10~20min, keep it at 100~160℃ for 1~3h, and gradually apply 0.5~2.0MPa pressure to the upper and lower surfaces of the mold; The temperature is raised from 100-160°C to 160-200°C in 10-20 minutes, and post-cured at 160-200°C for 1-3 hours while applying a pressure of 2.0-4.0 MPa to the upper and lower surfaces of the mold.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: 1. The present invention applies the process of coupling winding and molding to the preparation of simple structural parts such as satellite structural square tubes, which can effectively meet the requirements of satellite structural square tubes for load bearing, light weight, and rapid preparation of inner and outer contour stable right-angle edge forming, etc. It has the advantages of simple preparation, low cost, high product bearing strength, high structural rigidity, high degree of integration, good reliability, etc., and is of great significance to the realization of satellite lightweighting; 2. The present invention can design molds and layers according to different service conditions. The product has good designability and can be manufactured by integral molding, which is beneficial to improving bearing strength, structural rigidity and service efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 This is a schematic diagram of the structure of a satellite square tube in an embodiment of the present invention; Figure 2 An axonometric view of a core mold in an embodiment of the present invention; Figure 3 It is an axonometric view of the die in the first embodiment of the present invention; Figure 4 It is a front view of the die in the first embodiment of the present invention; Figure 5 It is an axonometric view of the die in the second embodiment of the present invention; Figure 6 It is a front view of the die in the second embodiment of the present invention.

[0019] Figure numbers: core mold 1, first molding surface 101, pull rod 102, upper pressure strip 2, fourth molding surface 201, fifth molding surface 202, second inclined surface 203, sixth inclined surface 204, top pressure strip 205, left pressure strip 206, third inclined surface 207, fourth inclined surface 208, lower pressure strip 3, second molding surface 301, third molding surface 302, first inclined surface 303, fifth inclined surface 304, bottom pressure strip 305, right pressure strip 306, seventh inclined surface 307, eighth inclined surface 308.

[0020] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] This embodiment discloses a composite material structure square tube forming mold for satellites, which mainly includes a core mold 1 and a pressure mold, and is mainly used for forming Figure 1 Satellite square tube shown.

[0027] refer to Figure 2 The core mold 1 is a hollow or rectangular strip structure, and its specific size is adapted to the inner wall size of the satellite square tube to be formed. The four sides of the core mold 1 are first molding surfaces 101, which are respectively used to mold the four inner wall surfaces of the satellite square tube to be formed. The end of the core mold 1 has a pull rod 102, which is used to pull out the core mold 1 when demolding.

[0028] refer to Figure 3 , Figure 4 The die includes an upper press strip 2 and a lower press strip 3, and the cross sections of the upper press strip 2 and the lower press strip 3 are both L-shaped structures. The inner wall of the lower press strip 3 has a second molding surface 301 and a third molding surface 302, the second molding surface 301 is used for molding the lower outer wall of the satellite square tube to be molded, and the third molding surface 302 is used for molding the right outer wall of the satellite square tube to be molded. The inner wall of the upper press strip 2 has a fourth molding surface 201 and a fifth molding surface 202, the fourth molding surface 201 is used for molding the upper outer wall of the satellite square tube to be molded, and the fifth molding surface 202 is used for molding the left outer wall of the satellite square tube to be molded.

[0029] In this embodiment, the first end of the lower pressure strip 3 is beveled to match the second end of the upper pressure strip 2, and the second end of the lower pressure strip 3 is beveled to match the first end of the upper pressure strip 2. Due to the structural limitations of the hot press, only vertical pressure can be provided during the hot pressing and curing process. Therefore, during the molding process, the upper and lower sides of the molded satellite square tube often have a molding effect, while the left and right sides can only be pressed by the rigidity of the die, and the molding effect is often weaker than the upper and lower sides. Therefore, in this embodiment, the lower pressure strip 3 and the upper pressure strip 2 are beveled to decompose part of the vertical pressure of the hot press to the horizontal direction, so that the left and right sides of the satellite square tube to be molded can also be subjected to sufficient pressure, thereby improving the overall molding effect of the satellite square tube.

[0030] In the specific implementation process, the first end of the lower bead 3 is adjacent to the second molding surface 301, the second end of the upper bead 2 is adjacent to the fifth molding surface 202, the second end of the lower bead 3 is adjacent to the third molding surface 302, and the first end of the upper bead 2 is adjacent to the fourth molding surface 201. The first end of the lower bead 3 is provided with a first inclined surface 303, and the top end of the first inclined surface 303 is inclined in a direction away from the second molding surface 301. The second end of the upper bead 2 is provided with a second inclined surface 203, and the bottom end of the second inclined surface 203 is inclined in a direction close to the fifth molding surface 202. The inclination angles of the first inclined surface 303 and the second inclined surface 203 are both 30°~60°, and the first inclined surface 303 and the second inclined surface 203 are beveled to match. At the same time, a fifth inclined surface 304 is provided at the second end of the lower pressure strip 3, and the top end of the fifth inclined surface 304 is inclined in a direction close to the third molding surface 302; a sixth inclined surface 204 is provided at the first end of the upper pressure strip 2, and the bottom end of the sixth inclined surface 204 is inclined in a direction away from the fourth molding surface 201; the inclination angles of the fifth inclined surface 304 and the sixth inclined surface 204 are both 30°~60°, and the fifth inclined surface 304 is beveled and matched with the sixth inclined surface 204.

[0031] As a preferred embodiment, the upper press strip 2 includes a separate top press strip 205 and a left press strip 206, the fourth molding surface 201 is located on the top press strip 205, and the fifth molding surface 202 is located on the left press strip 206. Figure 5 , Figure 6 As shown. The second inclined surface 203 is located at the bottom side of the left bead 206, and the top side of the left bead 206 is provided with a third inclined surface 207, and the top end of the third inclined surface 207 is inclined in the direction close to the fifth molding surface 202, that is, the cross section of the left bead 206 is a trapezoidal structure with two inclined surfaces. The left end of the top bead 205 is provided with a fourth inclined surface 208, and the bottom end of the fourth inclined surface 208 is inclined in the direction away from the fourth molding surface 201. The inclination angles of the third inclined surface 207 and the fourth inclined surface 208 are both 30°~60°, and the third inclined surface 207 and the fourth inclined surface 208 are beveled and matched, that is, during the process of applying pressure by the hot press, the top bead 205 and the lower bead 3 simultaneously provide leftward pressure to the left bead 206, ensuring that the left side wall of the satellite square tube has a better molding effect.

[0032] As a preferred embodiment, the lower press strip 3 includes a separate bottom press strip 305 and a right press strip 306, the second molding surface 301 is located on the bottom press strip 305, and the third molding surface 302 is located on the right press strip 306. Figure 5 , Figure 6As shown. The fifth inclined surface 304 is located on the top side of the right bead 306, and the bottom side of the right bead 306 is provided with a seventh inclined surface 307, and the bottom end of the seventh inclined surface 307 is inclined in the direction close to the third molding surface 302, that is, the cross section of the right bead 306 is a trapezoidal structure with two inclined surfaces. The right end of the bottom bead 305 is provided with an eighth inclined surface 308, and the top end of the eighth inclined surface 308 is inclined in the direction away from the second molding surface 301. The inclination angles of the seventh inclined surface 307 and the eighth inclined surface 308 are both 30°~60°, and the seventh inclined surface 307 is beveled with the eighth inclined surface 308, that is, during the process of applying pressure by the hot press, the bottom bead 305 and the upper bead 2 simultaneously provide rightward pressure to the right bead 306, ensuring that the right side wall of the satellite square tube has a better molding effect.

[0033] Based on the above-mentioned satellite composite material structure square tube forming mold, this embodiment also discloses a method for preparing a satellite composite material structure square tube, comprising the following steps: According to the outer dimensions of the square tube to be prepared, combined with the characteristics and requirements of the molding process, a core mold and a compression mold of corresponding sizes are prepared, and the working surface of the mold is cleaned, polished, and coated with a release agent to obtain a spare mold; According to the service environment of the product, epoxy 648 resin and high-performance carbon fiber T700, T800, M40, M55J with a single fiber fineness of 3K, 6K or 12K are selected as the raw materials of the components; Prepare the resin solution, adjust its viscosity and add it into the roller groove of the winding machine so that the surface of the carbon fiber yarn is evenly covered with the resin solution to ensure that the carbon fiber yarn is impregnated; Adjust the tension of the carbon fiber yarn on the winding machine, start the winding machine, and wind and lay the layers on the core mold according to the layup design. The layup design adopts the composite material lamination theory, takes the bearing capacity and deformation of the composite material component as the optimization index, and designs and optimizes the layup structure of the target composite material component; Take the wound core mold off the winding machine, close it with the prepared die, and check the degree of mold closing; Place the entire mold in a hot press and perform hot pressing and curing according to a certain curing system; After curing is completed, demoulding and trimming are performed to obtain a composite material structure satellite square tube component.

[0034] In the specific implementation process, the materials for preparing the resin solution include base resin, curing agent and solvent. Among them, the base resin is epoxy 648 resin; the curing agent is boron trifluoride monoethylamine, the amount of which is 1% to 5% of the mass of the base resin; the solvent is acetone, the amount of which is 30% to 60% of the base resin.

[0035] During the process of winding and laying the core mold, the laying angles are symmetrically arranged in a certain order according to various direction angles of 0°, ±30°, ±45°, and 90°, preferably in a submissive arrangement of 0°, -45°, 45°, 0°, 0°, 45°, -45°, and 0°, and the layer thickness is 0.2mm~0.4mm.

[0036] In the specific implementation process, the process of checking the degree of mold closing is as follows: using a combination of visual inspection and dimensional measurement, after completing the mold closing, while ensuring that the die is placed on a horizontal surface, looking straight from the front view of the mold, there should be no extra gap between the die and the core mold except for the necessary fiber winding body space visible to the eye; using a laser level or plumb line to inspect the side wall of the die, the vertical dimension should not exceed plus or minus 3°. If the inspection does not meet the requirements, the core mold is removed from the die and the mold is closed again. Given that the resin-impregnated fiber layer has a high viscosity, the outermost layer will be affected during the removal process. Therefore, the outermost layer is peeled off and re-laid, and then the mold is closed again for inspection.

[0037] In the specific implementation process, the process of hot pressing curing is specifically as follows: The mold is heated from room temperature to 80-100°C in 10-20 minutes, and kept at 80-100°C for 4-6 hours. At the same time, a pressure of 0.1-0.3MPa is applied to the upper and lower working surfaces of the mold. When the temperature is 80-100°C, the resin solution begins to undergo a cross-linking reaction, but has not yet been completely cured. In order to control the cross-linking reaction of small molecules, a certain temperature control and conformal control are performed, so a certain pressure is applied; The temperature is raised from 80-100°C to 100-160°C in 10-20 minutes. While maintaining the temperature at 100-160°C for 1-3 hours, a pressure of 0.5-2.0 MPa is gradually applied to the upper and lower surfaces of the mold. When the temperature is 100-160°C, the resin solution undergoes a more intense cross-linking reaction to form a more stable network structure. At the same time, a greater pressure is applied to the winding body to make it fit the mold more closely and obtain the desired right-angle appearance. It takes 10-20 minutes to raise the temperature from 100-160℃ to 160-200℃, and post-curing treatment is carried out at 160-200℃ for 1-3 hours. At the same time, a pressure of 2.0-4.0MPa is applied to the upper and lower surfaces of the mold. When the temperature is 160-200℃, the active groups in the material react completely, and the heat resistance and mechanical properties of the material will be further improved. Therefore, greater pressure is applied to obtain a square tube material with mechanical properties that meet the requirements.

[0038] The preparation method in this embodiment is further described below in conjunction with specific examples.

[0039] Example 1: Prepare a satellite structure square tube, the process steps are as follows: 1. Mold preparation According to the outer dimensions of the required square tube (400mm×25mm×30mm), combined with the characteristics and requirements of the molding process, the corresponding mold system is designed and prepared—— Figure 2 , Figure 3 The core mold and the pressing mold shown are used to clean, polish, and coat the working surface of the obtained mold with a release agent to obtain a spare mold.

[0040] 2. Prepare resin solution Prepare the resin solution required for impregnating the fiber. The resin matrix system used is composed of epoxy resin, curing agent and solvent. The epoxy resin is epoxy 648 resin, the amount is 400g; the curing agent is boron trifluoride monoethylamine, the amount is 3% of the mass of the epoxy resin used; the solvent is acetone, the amount is 50% of the mass of the epoxy resin used. After the preparation is completed, check its viscosity to ensure that the resin solution maintains a certain fluidity.

[0041] 3. Winding core mold Prepare M40 carbon fiber with a monofilament fineness of 6K, pour the prepared resin solution into the roller groove of the winding machine to fully impregnate the carbon fiber with the resin solution, adjust and check the fiber tension, start the winding machine, and wind the fiber layers on the core mold according to the set laying sequence (0°, -45°, 45°, 0°, 0°, 45°, -45°, 0°) with a thickness of 0.25mm per layer.

[0042] 4. Mold fixing After the winding is completed, the core mold and the winding body are placed as a whole in the prepared pressing mold. The shape and size of the mold cavity formed by the core mold and the pressing mold are the same as the size of the square tube obtained by laying.

[0043] 5. Preheat The mold was placed in a hot press and preheated to 93°C.

[0044] 6. Pressurize and cure Adjust the program parameters of the hot press to raise the temperature of the resin in the mold from room temperature to 93°C in 10 minutes, keep it at 93°C for 5 hours, and apply a pressure of 0.2 MPa to the upper and lower working surfaces of the mold; raise the temperature from 93°C to 130°C in 10 minutes, keep it at 130°C for 2 hours, and gradually apply a pressure of 1.0 MPa to the upper and lower surfaces of the mold; raise the temperature from 130°C to 170°C in 10 minutes, and post-cure it at 170°C for 2 hours, while applying a pressure of 2.0 MPa to the upper and lower surfaces of the mold.

[0045] 7. Demolding and post-processing Demoulding, trimming and cleaning are carried out to obtain the required satellite structure square tube.

[0046] The satellite structure square tube prepared in this embodiment uses epoxy 648 resin as a matrix material and M40 fiber as a reinforcement material. The flexural strength of the satellite structure square tube is 58.82 MPa.

[0047] Example 2: Prepare a satellite structure square tube. The specific process steps are as follows: 1. Mold preparation According to the outer dimensions of the required square tube (500mm×25mm×30mm), combined with the characteristics and requirements of the molding process, the corresponding mold system is designed and prepared—— Figure 2 , Figure 4 The core mold and the pressing mold shown are used to clean, polish, and coat the working surface of the obtained mold with a release agent to obtain a spare mold.

[0048] 2. Prepare resin solution Prepare the resin solution required for impregnating the fiber. The resin matrix system used is composed of epoxy resin, curing agent and solvent. The epoxy resin is epoxy 648 resin, the amount is 800g; the curing agent is boron trifluoride monoethylamine, the amount is 3% of the mass of the epoxy resin used; the solvent is acetone, the amount is 50% of the mass of the epoxy resin used. After the preparation is completed, check its viscosity to ensure that the resin solution maintains a certain fluidity.

[0049] 3. Winding core mold Prepare T700 carbon fiber with a monofilament fineness of 6K, pour the resin solution prepared in step 1 into the roller groove of the winding machine to fully impregnate the carbon fiber with the resin solution, adjust and check the fiber tension, start the winding machine, and perform fiber laying and winding on the core mold according to the set laying sequence (0°, 45°, 90°, -45°, 0°, -45°, 90°, 45°, 0°), with a thickness of 0.2mm per layer.

[0050] 4. Mold fixing After the winding is completed, the core mold and the winding body are placed as a whole in the prepared pressing mold. The shape and size of the mold cavity formed by the core mold and the pressing mold are the same as the size of the square tube obtained by laying.

[0051] 5. Preheat The mold was placed in a hot press and preheated to 93°C.

[0052] 6. Pressurize and cure Adjust the program parameters of the hot press to raise the temperature of the resin in the mold from room temperature to 93°C in 10 minutes, keep it at 93°C for 5 hours, and apply a pressure of 0.2 MPa to the upper and lower working surfaces of the mold; raise the temperature from 93°C to 130°C in 10 minutes, keep it at 130°C for 2 hours, and gradually apply a pressure of 1.0 MPa to the upper and lower surfaces of the mold; raise the temperature from 130°C to 170°C in 10 minutes, and post-cure it at 170°C for 2 hours, while applying a pressure of 2.0 MPa to the upper and lower surfaces of the mold.

[0053] 7. Demolding and post-processing Demoulding, trimming and cleaning are carried out to obtain the required satellite structure square tube.

[0054] The satellite structure square tube prepared in this example uses epoxy 648 resin as the matrix material and T700 fiber as the reinforcement material. The flexural strength of the satellite structure square tube is 38.61 MPa.

[0055] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A composite material square tube forming die for satellites, characterized in that: Including core mold and die; The core mold is a rectangular strip structure having four first molding surfaces, which are respectively used for molding four inner walls of the square tube; The die comprises an upper press strip and a lower press strip, and the cross-sections of the upper press strip and the lower press strip are both L-shaped: The lower pressing strip has a second molding surface and a third molding surface, which are used for molding the lower outer wall and the right outer wall of the square tube respectively; The upper pressure strip has a fourth molding surface and a fifth molding surface, which are used for molding the upper outer wall and the left outer wall of the square tube respectively; The first end of the lower press strip is beveled and matched with the second end of the upper press strip, and the second end of the lower press strip is beveled and matched with the first end of the upper press strip.

2. The satellite composite material structure square tube forming mold according to claim 1, characterized in that: The first end of the lower press strip is adjacent to the second molding surface, and the second end of the upper press strip is adjacent to the fifth molding surface; A first inclined surface is provided at the first end of the lower pressing strip, and a top end of the first inclined surface is inclined in a direction away from the second forming surface; A second inclined surface is provided at the second end of the upper press strip, and a bottom end of the second inclined surface is inclined toward a direction close to the fifth molding surface; The inclination angles of the first inclined surface and the second inclined surface are both 30° to 60°, and the first inclined surface is beveled to match the second inclined surface.

3. The satellite composite material structure square tube forming mold according to claim 2, characterized in that: The upper press strip includes a top press strip and a left press strip that are separated, the fourth molding surface is located on the top press strip, and the fifth molding surface is located on the left press strip; The second inclined surface is located at the bottom side of the left press strip, a third inclined surface is provided at the top side of the left press strip, and the top end of the third inclined surface is inclined toward the direction close to the fifth molding surface; A fourth inclined surface is provided at the left end of the top pressure strip, and the bottom end of the fourth inclined surface is inclined in a direction away from the fourth molding surface; The inclination angles of the third inclined surface and the fourth inclined surface are both 30°-60°, and the third inclined surface is bevel-cut and matched with the fourth inclined surface.

4. The satellite composite material structure square tube forming mold according to claim 1, 2 or 3, characterized in that: The second end of the lower press strip is adjacent to the third molding surface, and the first end of the upper press strip is adjacent to the fourth molding surface; A fifth inclined surface is provided at the second end of the lower pressing strip, and the top end of the fifth inclined surface is inclined toward a direction close to the third forming surface; A sixth inclined surface is provided at the first end of the upper press strip, and a bottom end of the sixth inclined surface is inclined in a direction away from the fourth molding surface; The inclination angles of the fifth inclined surface and the sixth inclined surface are both 30°-60°, and the fifth inclined surface is bevel-cut and matched with the sixth inclined surface.

5. The satellite composite material structure square tube forming mold according to claim 4, characterized in that: The lower press strip includes a separate bottom press strip and a right press strip, the second molding surface is located on the bottom press strip, and the third molding surface is located on the right press strip; The fifth inclined surface is located on the top side of the right bead, and a seventh inclined surface is provided on the bottom side of the right bead, and the bottom end of the seventh inclined surface is inclined toward the direction close to the third molding surface; An eighth inclined surface is provided at the right end of the bottom press strip, and the top end of the eighth inclined surface is inclined in a direction away from the second forming surface; The inclination angles of the seventh inclined surface and the eighth inclined surface are both 30°-60°, and the seventh inclined surface is bevel-cut and matched with the eighth inclined surface.

6. A method for preparing a composite material square tube for satellite, characterized in that: Using the molding die according to any one of claims 1 to 5; The preparation method comprises the following steps: Step 1, prepare the resin solution, adjust its viscosity and add it into the roller groove of the winding machine, so that the surface of the carbon fiber yarn is evenly covered with the resin solution to ensure that the carbon fiber yarn is impregnated; Step 2, adjusting the tension of the carbon fiber yarn on the winding machine, starting the winding machine, and winding and laying the core mold according to the layup design; Step 3, remove the wound core mold, place it in the die, close the mold, and check the degree of mold closing; Step 4, placing the entire mold in a hot press and performing hot pressing curing according to a certain curing system; Step 5, after curing is completed, demoulding and trimming are performed to obtain a composite material structure satellite square tube component.

7. The method for preparing a composite material structural square tube for satellite according to claim 6, characterized in that: The carbon fiber yarn is one of high-performance carbon fibers T700, T800, M40, and M55J, with a single-filament fineness of 3K, 6K, or 12K.

8. The method for preparing a composite material structural square tube for satellite according to claim 6, characterized in that: In step 1, the materials for preparing the resin solution include base resin, curing agent and solvent; The base resin is epoxy 648 resin; The curing agent is boron trifluoride monoethylamine, and the amount used is 1% to 5% of the mass of the base resin; The solvent is acetone, and the amount used is 30% to 60% of the base resin.

9. The method for preparing a composite material structural square tube for satellite according to claim 6, characterized in that: In step 2, during the process of winding and laying the core mold, the laying angles are symmetrically arranged in a certain order according to multiple direction angles of 0°, ±30°, ±45°, and 90°, and the thickness of the layer is 0.2mm~0.4mm.

10. The method for preparing a composite material structural square tube for satellite according to claim 6, characterized in that: In step 4, the process of hot pressing curing is specifically as follows: Heat the mold from room temperature to 80-100°C in 10-20 minutes, keep it at 80-100°C for 4-6 hours, and apply a pressure of 0.1-0.3MPa to the upper and lower working surfaces of the mold; Raise the temperature from 80~100℃ to 100~160℃ in 10~20min, keep it at 100~160℃ for 1~3h, and gradually apply 0.5~2.0MPa pressure to the upper and lower surfaces of the mold; The temperature is raised from 100-160°C to 160-200°C in 10-20 minutes, and post-cured at 160-200°C for 1-3 hours while applying a pressure of 2.0-4.0 MPa to the upper and lower surfaces of the mold.

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