Composite truss forming die and forming method thereof

Abstract

The invention provides a composite material truss forming mold and a forming method thereof, and belongs to the technical field of composite material forming. The problems that an existing satellite composite material is poor in bearing capacity and low in space utilization rate are solved. The device comprises an outer pressurizing frame, outer molds, split molds, a bottom plate mold and a core mold, composite material trusses are laid on the split molds to obtain prepreg, the split molds with the laid prepreg are installed on the core mold, the core mold is installed on the bottom plate mold, the three outer molds are evenly distributed on the bottom plate mold, the outer pressurizing frame is installed on the outer sides of the three outer molds, and the outer pressurizing frame is installed on the outer sides of the three outer molds. The sectioning mold on which the prepreg is laid is connected with the core mold through a bolt and a positioning pin, the core mold is connected with the bottom plate mold through a bolt and a positioning pin, and the composite material truss is made of a carbon fiber epoxy resin composite material. The method is mainly used for forming the carbon fiber composite material supporting structure.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material forming, and in particular relates to a composite material truss forming die and a forming method thereof. Background Art

[0002] In recent years, micro-satellites have become a research hotspot due to their low cost, short R&D cycle, easy satellite formation networking, and satellite constellation operation. Carbon fiber composite materials can be used as the support structure of satellites and their space cameras, which plays an important role in the stable operation, weight reduction, and cost reduction of high-resolution micro-satellites. At present, there are three main load-bearing structures of satellite composite materials in the world, namely box-plate type, load-bearing cylinder type, and truss type. The traditional box-plate type has a simple structure, compact layout, low cost, but poor bearing capacity; the load-bearing cylinder type has strong bearing capacity, but low space utilization. Summary of the invention

[0003] In view of this, the present invention aims to provide a composite material truss forming die and a forming method thereof, so as to solve the problems of poor bearing capacity and low space utilization of existing satellite composite materials.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A composite material truss forming mold comprises an external pressure frame, an outer mold, a flap mold, a base plate mold and a core mold, the flap mold is laid with prepreg of the composite material truss, the flap mold with the prepreg laid is installed on the core mold, the core mold is installed on the base plate mold, three outer molds are evenly distributed on the base plate mold, and the external pressure frame is installed on the outside of the three outer molds.

[0006] Furthermore, the split mold with the prepreg laid is connected to the core mold through bolts and positioning pins.

[0007] Furthermore, the core mold is connected to the base plate mold through bolts and positioning pins.

[0008] Furthermore, the composite material truss is made of carbon fiber epoxy resin composite material.

[0009] Furthermore, the composite material truss is provided with reinforcing ribs with a thickness of 1-3 mm.

[0010] A forming method of a composite material truss forming mold comprises the following steps:

[0011] Step 1: Prepare prepreg, impregnate epoxy resin with carbon fiber to obtain prepreg, process composite truss forming mold according to the drawing, prepare sandpaper for polishing the mold and silicone grease for mold assembly;

[0012] Step 2: Cut the prepreg into the required size and then lay it out in the split mold;

[0013] Step 3: After the laying is completed, fix the split mold on the core mold, and then fix the core mold on the base mold. At the same time, place the three outer molds on the base mold in sequence, and finally wrap them with an external pressure frame for pressurization and tightening;

[0014] Step 4: Curing is carried out according to the epoxy resin fixing system. After curing is completed, the product is cooled in the curing furnace and demoulding is carried out after cooling;

[0015] Step 5: After the product is demoulded, correct the surface and smooth the burrs with a file;

[0016] Step 6: Analyze the composite truss modal.

[0017] Furthermore, in step 1, the carbon fiber prepreg is prepared by hot melt prepreg method.

[0018] Furthermore, in step 2, the layers are laid on the split mold in a circular mirroring manner according to the laying angles of 0 / 90 / 45 / -45°ns.

[0019] Furthermore, in step 4, the curing regime of the epoxy resin is 100°C / 2h-150°C / 2h.

[0020] Furthermore, when demolding is performed in step 4, demolding is performed in the order of the external pressure frame, the base plate mold, the outer mold, the core mold and the petal mold.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The lower thin-walled tube and the upper truss rod of the composite material truss formed by the molding mold of the present invention are integrally formed, and the combined carbon fiber support structure can improve the lightweight degree of the structure to a certain extent.

[0023] 2. The mold of the present invention has been installed and disassembled, which improves the work efficiency in the process of mold closing and demoulding of preparing composite material trusses.

[0024] 3. The composite material truss prepared by the molding mold of the present invention is integrally formed and has the advantage of being easy to install and adjust, thereby improving the stability of the satellite space camera support structure and playing an important role in improving the resolution of the space camera.

[0025] 4. The present invention improves the bearing capacity of the composite material truss, has a compact structure, high functional density, a short creation path, and high lightweight performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 It is a structural schematic diagram of a composite material truss forming mold according to the present invention;

[0028] Figure 2 It is a schematic structural diagram of the composite material truss described in the present invention.

[0029] 1-external pressure frame, 2-external mold, 3-composite material truss, 4-petal mold, 5-bottom plate mold, 6-core mold. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0031] Specific implementation method 1: See Figure 1-2 To illustrate the present embodiment, a composite material truss forming mold includes an external pressure frame 1, an outer mold 2, a flap mold 4, a base plate mold 5 and a core mold 6. The flap mold 4 is laid with prepreg of the composite material truss 3, and the flap mold 4 with the prepreg laid is installed on the core mold 6. The core mold 6 is installed on the base plate mold 5. Three outer molds 2 are evenly distributed on the base plate mold 5, and the external pressure frame 1 is installed on the outside of the three outer molds 2.

[0032] The split mold 4 with prepreg laid is connected to the core mold 6 by bolts and locating pins, and the core mold 6 is connected to the base plate mold 5 by bolts and locating pins. The composite truss 3 adopts carbon fiber epoxy resin composite material, and the composite truss 3 is provided with reinforcing ribs with a thickness of 1-3mm.

[0033] First, the composite truss mold is designed and re-inspected before entering the factory. The mold's external dimensions and surface finish must meet the design requirements. After the mold meets the design requirements, it is disassembled and degreased, and the surface is polished with fine sandpaper and wiped clean with acetone for later use. Then, according to the composite material ply design criteria and actual engineering experience, the prepreg ply 0 / 90 / 45 / -45ns is designed and laid in the split mold 4. All the inner corners are flattened with an auxiliary tool putty knife to ensure that the prepreg is firmly attached, not suspended, and not bridged. After the prepreg is laid, the excess part is trimmed with a wallpaper knife, and the prepreg is pressed by external pressure. Frame 1 provides pressure to the prepreg, and puts the mold into the curing furnace under pressure. It is cured and formed according to the resin curing system of 100℃ / 2h-150℃ / 2h. The lower thin-walled tube and the upper truss rod of the cured composite truss are integrally formed. The combined carbon fiber support structure can improve the lightweight degree of the structure to a certain extent, has the advantage of easy installation and adjustment, improves the stability of the satellite space camera support structure, and plays an important role in improving the resolution of the space camera. In addition, the mold is easy to install and disassemble during mold closing and demolding, thereby improving work efficiency.

[0034] Specific implementation method 2: See Figure 1-2 The present embodiment describes a method for forming a composite material truss forming mold, which comprises the following steps:

[0035] Step 1: Prepare prepreg, impregnate epoxy resin with carbon fiber to obtain prepreg, process composite truss forming mold according to the drawing, prepare sandpaper for polishing the mold and silicone grease for mold assembly. Carbon fiber prepreg is prepared by hot melt prepreg method;

[0036] Step 2: Cut the prepreg into the required size, and then lay it on the split mold 4, and lay it on the split mold 4 according to the layup angle (0 / 90 / 45 / -45°)ns circular mirror image;

[0037] Step 3: After the laying is completed, the split mold 4 is fixed on the core mold 6, and then the core mold 6 is fixed on the base mold 5, and the three outer molds 2 are placed on the base mold 5 in sequence, and finally wrapped with an external pressure frame 1 for pressurization and tightening;

[0038] Step 4: Curing is performed according to the epoxy resin fixing system. The curing system of the epoxy resin is 100°C / 2h-150°C / 2h. After the curing is completed, the product is cooled in the curing furnace. After cooling, the product is demoulded. When demoulding, the demoulding is performed in the order of the external pressure frame 1, the bottom plate mold 5, the outer mold 2, the core mold 6 and the petal mold 4;

[0039] Step 5: After the product is demoulded, correct the surface and smooth the burrs with a file;

[0040] Step 6: Analyze the 3 modes of the composite truss.

[0041] The composite truss adopts high modulus carbon fiber epoxy resin composite material. The high modulus composite material is not easy to deform when carrying the engine, and has strong stability. The carbon fiber prepreg is prepared by hot melt prepreg method. Under a certain temperature and pressure, the epoxy resin is fully impregnated with the carbon fiber to obtain the prepreg. After the composite truss mold is designed, it is processed according to the drawings. The mold is first degreased after leaving the factory. After passing the inspection, all the detachable petals connected by bolts are disassembled, and the mold surface is polished with 100 mesh sandpaper. Then the female mold and the male mold are assembled separately for prepreg molding, sandpaper is prepared for mold polishing, silicone grease is prepared for mold assembly, and it is easy to demold after curing. Wallpaper knives, scissors, etc. are prepared for product molding. The prepreg is cut into a size that is convenient for laying, and laid on the petal mold 4 according to the laying angle (0 / 90 / 45 / -45°)ns loop mirror. When laying, pay attention to the prepreg to fit the mold, and the laying of layers at various angles. The prepreg layers should be tightly fitted and bubbles should be driven out. After laying, the prepreg layers are fixed to the core mold 6 by bolts and locating pins, and then the core mold is fixed to the base mold 5 by bolts and locating pins. At the same time, the three outer molds 2 are placed on the base mold 5 in sequence. Finally, all the molds are wrapped with an external pressure frame 1 for pressurization and tightening to provide curing pressure for the composite truss 3. The composite truss products should be cured according to the curing system of epoxy resin, that is, 100℃ / 2h-150℃ / 2h. After the curing temperature is completed, they should be cooled in the curing furnace to ensure that the mold temperature drops to no more than 30℃ from room temperature before the product can be demoulded. Demolding should be carried out in the opposite order of the combined mold, and demoulding should be carried out in the order of external pressure frame 1, base mold 5, outer mold 2, core mold 6 and petal mold 4. The modal analysis results of the truss show that there is no weak stiffness position in the main structure of the composite material, and the strength of the main load-bearing structure and the satellite stiffness meet the dynamic requirements of the space camera.

[0042] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A composite material truss forming mold, characterized in that: It comprises an external pressure frame (1), an external mold (2), a split mold (4), a base mold (5) and a core mold (6); the split mold (4) is provided with prepreg of a composite material truss (3); the split mold (4) with the prepreg is installed on the core mold (6); the core mold (6) is installed on the base mold (5); three external molds (2) are evenly distributed on the base mold (5); and the external pressure frame (1) is installed on the outside of the three external molds (2).

2. The composite material truss forming mold according to claim 1, characterized in that: The split mold (4) on which the prepreg is laid is connected to the core mold (6) via bolts and positioning pins.

3. The composite material truss forming mold according to claim 1, characterized in that: The core mold (6) is connected to the base plate mold (5) via bolts and positioning pins.

4. The composite material truss forming mold according to claim 1, characterized in that: The composite material truss (3) is made of carbon fiber epoxy resin composite material.

5. The composite material truss forming mold according to claim 1, characterized in that: The composite material truss (3) is provided with reinforcing ribs with a thickness of 1-3 mm.

6. A method for forming a composite material truss forming mold according to any one of claims 1 to 5, characterized in that: It includes the following steps: Step 1: Prepare prepreg, impregnate epoxy resin with carbon fiber to obtain prepreg, process composite truss forming mold according to the drawing, prepare sandpaper for polishing the mold and silicone grease for mold assembly; Step 2: cutting the prepreg into the required size and then laying it on the split mold (4); Step 3: After the laying is completed, the split mold (4) is fixed on the core mold (6), and then the core mold (6) is fixed on the base mold (5). At the same time, the three outer molds (2) are placed on the base mold (5) in sequence, and finally wrapped with an external pressure frame (1) for pressurization and tightening; Step 4: Curing is carried out according to the epoxy resin fixing system. After curing is completed, the product is cooled in the curing furnace and demoulding is carried out after cooling; Step 5: After the product is demoulded, correct the surface and smooth the burrs with a file; Step 6: Perform modal analysis on the composite truss (3).

7. The forming method of the composite material truss forming mold according to claim 6, characterized in that: In step 1, the carbon fiber prepreg is prepared by hot melt prepreg method.

8. The forming method of the composite material truss forming mold according to claim 6, characterized in that: In step 2, the layers are laid on the split mold (4) according to the laying angle (0 / 90 / 45 / -45°) ns circular mirroring.

9. The forming method of the composite material truss forming mold according to claim 6, characterized in that: The curing regime of the epoxy resin in step 4 is 100°C / 2h-150°C / 2h.

10. The forming method of the composite material truss forming mold according to claim 6, characterized in that: When demoulding in step 4, demoulding is performed in the order of the external pressure frame (1), the base plate mold (5), the outer mold (2), the core mold (6) and the split mold (4).

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