Mold, composite material product and preparation method of composite material product
By designing grooves in the mold and using high temperature -resistant silicone elastic buffer body, the contraction force of the outer mold is cushioned, and the squeezing problem caused by the difference in thermal expansion of the mold products is solved to ensure the internal quality and mechanical performance of the product.
Patent Information
- Application Number
- CN202411543737.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-01-24
AI Technical Summary
During the high-temperature curing process of composite materials, due to the difference in thermal expansion of metal molds, the product is subjected to the extrusion pressure caused by the shrinkage of the mold during the post-curing cooling stage, which is prone to damage and internal defects.
Design a mold, including core molds, external molds, elastic buffer bodies, and metal cubes. It uses grooves and elastic buffer to buffer the shrinkage of external molds during the high temperature solidification and cooling process to prevent damage to composite materials.
It effectively avoids the extrusion force caused by the shrinkage of the outer mold during the cooling stage of composite products after curing, prevents flanging damage and internal defects, and ensures the internal quality of the product.
Smart Images
Figure CN119348007A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of composite materials, and in particular relates to a mold, a composite material product and a preparation method thereof. Background Art
[0002] Composite products are usually solidified by laminates made of stacked unidirectional fiber prepreg tapes. Since composite materials have anisotropic characteristics, they can be stacked to form products with better strength and stiffness. Carbon fiber composites are high-performance materials with resin as the matrix and carbon fiber as the reinforcement. The specific strength and specific stiffness of carbon fiber composites are significantly better than those of metal composites, and lightweight requirements can also be met. In addition, carbon fiber composites have a low thermal expansion coefficient, so they have higher dimensional stability. Carbon fiber composites are widely used in the aerospace field due to their excellent mechanical and physical and chemical properties.
[0003] The dimensional stability of composite products is little affected by temperature, but their mechanical properties are affected by the temperature of the matrix material. As the ambient temperature rises, their mechanical properties decrease. Therefore, when used in fields such as aerospace, composite products must meet certain temperature resistance requirements. At this time, high-temperature resistant resins are usually selected as the matrix material of composite products, such as bismaleimide resins, polyimide resins, etc.
[0004] The glass transition temperature T g It is higher, so it also corresponds to a higher curing temperature. The mold for preparing products is usually made of metal material. Due to the high curing temperature, there is a large difference in thermal expansion between the product and the mold. For products with flanges or flanging, when they are prepared using metal molds, the products will be subject to a large extrusion force caused by the shrinkage of the mold during the cooling stage after curing. The flanges or flanging are easily damaged by the force, resulting in defects inside the product, reducing the mechanical properties of the product, and in severe cases, the product will be scrapped. Summary of the invention
[0005] In view of this, the present invention aims to provide a mold, a composite product and a preparation method thereof, which at least helps to alleviate the problem of extrusion of the composite product by the external mold during the preparation process.
[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows:
[0007] The invention provides a mold, comprising: a core mold, an outer mold, an elastic buffer body and a metal pad. When the mold is in a mold closing state, the outer mold is positioned on the outside of the core mold, and the surface of the outer mold facing the core mold and the surface of the core mold facing the outer mold form a mold cavity. The mold cavity is used to form a composite material product. The composite material product includes an integrally formed product body and a flange; the mold cavity includes a main body cavity and a flange cavity that are connected. The main body cavity is used to form the product body, and the flange cavity is used to form the flange; the outer mold is provided with a groove, and one end of the flange cavity away from the main body cavity is directly opposite to the groove, and the shape of the metal pad and the shape of the elastic buffer body both correspond to the groove; in the preparation process of the composite material product, the groove is used to set the metal pad in the pre-compacting step, and the groove is used to set the elastic buffer in the high-temperature curing step.
[0008] Furthermore, in the high temperature curing step, the elastic buffer body is fixed in the groove by bonding.
[0009] Furthermore, the glass transition temperature of the composite material product is not less than 200° C., the material of the outer mold includes metal, and the material of the elastic buffer body includes high temperature resistant silicone.
[0010] Furthermore, the thickness of the main cavity is the same as that of the flange cavity. In the direction perpendicular to the thickness of the flange cavity, the size of the groove is twice the thickness of the flange cavity. In the direction of the thickness of the flange cavity, the size of the groove is larger than the thickness of the flange cavity, and the difference between the size of the groove and the thickness of the flange cavity is within the range of 5mm to 10mm.
[0011] On the other hand, the present invention provides a method for preparing a composite material product, comprising: providing the above-mentioned mold, the mold comprising a core mold, an outer mold, an elastic buffer body and a metal pad; preparing a high-temperature system prepreg; laying the high-temperature system prepreg on the side of the core mold; placing the metal pad in the groove of the outer mold, and assembling the outer mold on the outside of the core mold with pressure bolts to pressurize the high-temperature system prepreg; releasing the pressure bolts to remove the outer mold from the core mold, replacing the metal pad with an elastic buffer body, and setting the elastic buffer body in the groove; assembling the outer mold on the outside of the core mold with pressure bolts to pressurize to achieve cold mold closing; high-temperature curing the high-temperature system prepreg to form a composite material product.
[0012] Furthermore, the high temperature curing step includes: heating the high temperature system prepreg in the mold cavity to the glass transition temperature, continuing heating for a preset time and then stopping heating, releasing the pressure bolts before the mold cools to room temperature, and removing the outer mold after releasing the pressure bolts to demold the composite product.
[0013] Furthermore, when the temperature of the mold drops to (T g / 2-T1)℃, release the pressure bolt, where T gT1 is the glass transition temperature of the high temperature system prepreg, and is in the range of 10 to 20.
[0014] Furthermore, when the temperature of the mold drops to T g / 3±5℃, remove the outer mold to demould the composite product, where T g It is the glass transition temperature of high temperature system prepreg.
[0015] In another aspect, the present invention provides a composite material product, which is prepared using the above-mentioned mold, or prepared using the above-mentioned composite material preparation method, and the composite material product includes an integrally formed product body and a flange.
[0016] Compared with the prior art, the invention can achieve the following beneficial effects: in the process of preparing a composite product, in the pre-compacting step, a groove is provided at the outer mold corresponding to the edge of the high-temperature system prepreg used to form the flange later, and a metal pad is installed in the groove, the purpose of which is to ensure that the shape of the high-temperature system prepreg after pre-compacting is the desired shape, and to prevent the prepreg from entering the groove in the pre-compacting step, that is, to preliminarily control the shape of the composite product formed later, because the flange of the composite product is susceptible to the extrusion force of the shrinkage of the outer mold during the cooling process after high-temperature curing, resulting in flange damage, in order to eliminate the influence of the shrinkage force of the outer mold, an elastic buffer is provided in the groove of the outer mold during the high-temperature curing and the cooling process after curing, so that during the process of the outer mold shrinking due to cooling, the contact between the flange edge and the outer mold is elastic, which is conducive to releasing the extrusion force of the outer mold on the flange, avoiding defects of the composite product of the high-temperature resin system due to the extrusion of the outer mold, and is conducive to ensuring the internal quality of the composite product. 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:
[0018] Figure 1 A schematic structural diagram of a mold and a composite material product according to an embodiment of the present invention.
[0019] Explanation of the reference numerals: 102, upper mold; 111, groove; 130, elastic buffer; 122, flange; 121, product body; 120, composite product; 101, main body; 110, outer mold; 141, main body cavity; 142, flange cavity; 140, mold cavity; 103, lower mold; X, second direction; Y, first direction; 104, first engaging corner; 105, second engaging corner. DETAILED DESCRIPTION
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.
[0025] refer to Figure 1The invention provides a mold, including: a core mold, an outer mold 110, an elastic buffer body 130 and a metal pad (not shown). When the mold is in a mold-closing state, the outer mold 110 is positioned outside the core mold, and the surface of the outer mold 110 facing the core mold and the surface of the core mold facing the outer mold 110 form a mold cavity 140. The mold cavity 140 is used to form a composite material product 120. The composite material product 120 includes an integrally formed product body 121 and a flange 122; the mold cavity 140 includes a main body cavity 121 and a flange 122 that are connected to each other. 41 and a flanging cavity 142, the main cavity 141 is used to form the product body 121, and the flanging cavity 142 is used to form the flanging 122; the outer mold 110 is provided with a groove 111, and the end of the flanging cavity 142 away from the main cavity 141 is directly opposite to the groove 111, and the shape of the metal pad and the shape of the elastic buffer body 130 both correspond to the groove 111; during the preparation process of the composite product 120, the groove 111 is used to set the metal pad in the pre-compacting step, and the groove 111 is used to set the elastic buffer body 130 in the high-temperature curing step.
[0026] In some embodiments of the present invention, the product body 121 extends along a first direction Y, and the flange 122 extends from the edge of the product body 121 along a second direction X away from the product body 121. The first direction Y can be perpendicular to the second direction X, and accordingly, the extension direction of the flange cavity 142 is also perpendicular to the extension direction of the main cavity 141.
[0027] In some embodiments of the present invention, the core mold includes a lower end mold 103, a main body 101 and an upper end mold 102 connected in sequence along a first direction Y, in a direction perpendicular to the first direction Y, the lower end mold 103 and the upper end mold 102 are both protruding from the main body 101, and the portion of the upper end mold 102 protruding from the main body 101 has a first engaging corner 104, and the portion of the lower end mold 103 protruding from the main body 101 has a second engaging corner 105, and the first engaging corner 104 and the second engaging corner 105 are opposite; the outer mold 110 includes a connected The protrusion and the engaging portion; when the mold is in the mold closing state, the engaging portion is engaged between the first engaging corner 104 and the second engaging corner 105, and the protrusion is located on the side of the engaging portion facing the main body 101, and a main body cavity 141 is formed between the main body 101 and the protrusion, and a flanging cavity 142 is formed between the protrusion and the upper end mold 102, or, a flanging cavity 142 is formed between the protrusion and the lower end mold 103, or, one flanging cavity 142 is formed between the protrusion and the lower end mold 103, and another flanging cavity 142 is formed between the protrusion and the upper end mold 102.
[0028] The mold provided in the embodiment of the present invention is used to prepare a composite material product 120 of a high temperature resin system having a flange 122. Therefore, the design of the mold should consider the following issues: Since the glass transition temperature T of the prepreg of the high temperature resin system is gIn the range of 200℃~350℃, therefore, the temperature during the curing process needs to reach the glass transition temperature T g During the curing process, when the temperature does not reach the glass transition temperature T g During the process of pressing the film before curing and the process of heating during curing, the prepreg used to prepare the composite product 120 will also be squeezed by the outer mold 110 and squeezed by the mold temperature expansion. However, since the composite product 120 has not yet been cured, it will not damage the composite product 120. This process will also squeeze and remove excess resin in the prepreg. When the curing temperature reaches the glass transition temperature T g Afterwards, as the curing temperature continues to rise, the resin matrix undergoes a cross-linking reaction. When the curing process enters the cooling stage, the prepreg has been transformed from an elastic body to a rigid body. Due to the difference in thermal expansion coefficients between the outer mold 110 and the composite product 120, the contraction amount of the cured composite product 120 is relatively small, while the contraction amount of the outer mold 110 made of metal material is relatively large, resulting in the composite product 120 being squeezed by the outer mold 110. Due to the anisotropic characteristics of the composite material, the composite product 120 has a strong ability to withstand the extrusion force along the thickness direction of the composite product 120, but has a weak ability to withstand the force perpendicular to the thickness direction of the composite product 120. Therefore, during the curing and cooling process, when the edge of the flange 122 is subjected to the extrusion force of the outer mold 110 perpendicular to the thickness direction of the flange 122, the flange 122 will be damaged due to the force.
[0029] It should be noted that the glass transition temperature T g is the glass transition temperature of the high temperature system prepreg, and the glass transition temperature of the high temperature system prepreg is the glass transition temperature of the resin matrix of the high temperature system prepreg.
[0030] In order to address the problem that the composite product 120 is damaged due to the difference in thermal expansion coefficients during the cooling stage after curing, an embodiment of the present invention provides the above-mentioned mold for preparing a high-temperature system composite product 120, wherein a groove 111 is arranged at a position of the outer mold 110 corresponding to the edge of the flange 122, and the size of the groove 111 is designed according to the thickness of the flange 122, the size of the metal pad used in the pre-compacting step is designed according to the size of the groove 111, and the size of the elastic buffer 130 is designed according to the size of the groove 111. During the cooling process after curing, the contact between the mold and the edge of the flange 122 is elastic, thereby releasing the extrusion force on the flange 122.
[0031] It should be noted that the metal spacer is designed according to the size of the groove 111 in order to ensure that the prepreg in the flanging cavity 142 does not overflow into the groove 111 during the pre-compacting step.
[0032] Furthermore, in the high temperature curing step, the elastic buffer body 130 is fixed in the groove 111 by bonding. Specifically, only the side surface of the elastic buffer body 130 away from the flange cavity 142 is bonded and fixed to the bottom surface of the groove 111 facing it.
[0033] Furthermore, the glass transition temperature of the composite material product 120 is not less than 200° C., the material of the outer mold 110 includes metal, the material of the elastic buffer body 130 includes high temperature resistant silicone, and the elastic buffer body 130 has high elasticity.
[0034] Furthermore, the heat-resistant temperature of the high-temperature resistant silicone is in the range of 320°C to 350°C.
[0035] Furthermore, the thickness of the main cavity 141 is the same as the thickness of the flange cavity 142. If the thickness of the main cavity 141 and the thickness of the flange cavity 142 are both defined as L1, along the direction perpendicular to the thickness of the flange cavity 142, the size L2 of the groove 111 is twice the thickness L1 of the flange cavity 142, that is, L2=2L1, and along the direction of the thickness of the flange cavity 142, the size L3 of the groove 111 is greater than the thickness of the flange cavity 142, and the difference between the size L3 of the groove 111 and the thickness of the flange cavity 142 is in the range of 5mm to 10mm, that is, along the direction of the thickness of the flange cavity 142, the size L3 of the groove 111 is in the range of L1+5mm to L1+10mm.
[0036] In some embodiments of the present invention, the material of the outer mold 110 and the material of the core mold may both include 45-grade steel.
[0037] On the other hand, the present invention also provides a method for preparing a composite material, including: providing the above-mentioned mold, the mold including a core mold, an outer mold 110, an elastic buffer body 130 and a metal pad; preparing a high-temperature system prepreg; laying the high-temperature system prepreg on the side of the core mold; placing the metal pad in the groove 111 of the outer mold 110, and assembling the outer mold 110 on the outside of the core mold with pressure bolts to pressurize the high-temperature system prepreg; releasing the pressure bolts to remove the outer mold 110 from the core mold, replacing the metal pad with an elastic buffer body 130, and setting the elastic buffer body 130 in the groove 111; assembling the outer mold 110 on the outside of the core mold with pressure bolts to pressurize and achieve cold mold closing; high-temperature curing the high-temperature system prepreg to form a composite material product 120.
[0038] In some embodiments of the present invention, the high temperature system prepreg may be a prepreg composed of carbon fiber and bismaleimide resin. In other embodiments of the present invention, the high temperature system prepreg may be a prepreg composed of carbon fiber and polyimide resin.
[0039] In some embodiments of the present invention, after laying the high temperature system prepreg on the side of the core mold, it also includes: laying an isolation film on the surface of the high temperature system prepreg, and then assembling the mold after laying the isolation film.
[0040] Furthermore, the high temperature curing step includes: heating the high temperature system prepreg in the mold cavity 140 of the mold to the glass transition temperature, continuing to heat for a preset time and then stopping the heating, releasing the pressure bolts before the mold cools to room temperature, and after releasing the pressure bolts, removing the outer mold 110 to demold the composite product 120. It should be noted that before the mold cools to room temperature, the outer mold 110 is removed to demold the composite product 120.
[0041] In order to eliminate the influence of the thermal stress caused by the shrinkage of the outer mold 110 on the composite product 120, in addition to setting an elastic buffer body 130 at the corresponding position on the outer mold 110, after high-temperature curing, the pressure bolts are released and the outer mold 110 is disassembled before the mold temperature drops to room temperature, thereby releasing the extrusion pressure of the outer mold 110 and avoiding the outer mold 110 from squeezing the flange 122. Choosing to disassemble the outer mold 110 in the high-temperature stage is beneficial to further reduce the influence of the shrinkage of the outer mold 110 on the composite product 120.
[0042] Furthermore, when the temperature of the mold drops to (T g / 2-T1)℃, release the pressure bolt, where T g is the glass transition temperature of the high temperature system prepreg, T1 is in the range of 10℃~20℃.
[0043] Furthermore, when the temperature of the mold drops to T g / 3±5℃, dismantle the outer mold 110 to demould the composite product 120, wherein T g It is the glass transition temperature of high temperature system prepreg.
[0044] Example 1
[0045] Step S1, providing a mold, the outer mold 110 has a groove 111 at a position corresponding to the edge of the flange 122, the thickness L of the composite material product 120 to be prepared can be in the range of 3mm to 5mm, and this embodiment is described by taking 5mm as an example, the thickness of the main cavity 141 and the thickness of the flange cavity 142 are both L1, L1=L=5mm, along the direction perpendicular to the thickness of the flange cavity 142, the size of the groove 111 is 2L=10mm, along the direction of the thickness of the flange cavity 142, the size of the groove 111 is in the range of 10mm to 15mm, the shape of the metal pad corresponds to the shape of the groove 111, the elastic buffer 130 is high temperature resistant silicone, and the shape of the high temperature resistant silicone corresponds to the shape of the groove 111;
[0046] Step S2, preparing a high temperature system prepreg, specifically, using carbon fiber and bismaleimide resin as raw materials to prepare the prepreg, wherein the glass transition temperature T g The temperature of the prepreg is about 240°C, and the single layer thickness of the high temperature system prepreg can be 0.2 mm. It should be noted that carbon fiber and polyimide resin can also be used as raw materials to prepare prepreg, wherein the glass transition temperature T g The temperature is about 350° C. This embodiment is described by taking carbon fiber and bismaleimide resin as raw materials to prepare prepreg as an example;
[0047] Step S3, using the prepared high temperature system prepreg to lay on the core mold for forming, the thickness of the high temperature system prepreg is about 5 mm, and the laying parameters can be [0 / +45 / 90 / -45 / 0]5;
[0048] Step S4, assembling the mold to pre-compact the high temperature system prepreg. Specifically, after the high temperature system prepreg is laid, an isolation film is placed on the surface of the high temperature system prepreg, and then the mold is assembled for pre-compaction. At this time, a rigid metal pad is arranged in the groove 111 to ensure the pre-compaction state of the high temperature system prepreg.
[0049] Step S5, after the above-mentioned pre-compacting step is completed, release the pressure bolts, remove the outer mold 110 from the core mold, take out the metal pad in the groove 111, bond the high temperature resistant silicone into the groove 111, and then perform cold mold closing and high temperature curing operations. High temperature curing requires heating to 240°C and maintaining for 4h to 6h.
[0050] Step S6, product demoulding. Specifically, in the cooling stage after high-temperature curing, the pressure bolts are released. When the composite product 120 is prepared by a high-temperature system prepreg including bismaleimide resin, the timing for releasing the pressure bolts is: releasing the pressure bolts when the mold temperature drops to any temperature between 100°C and 110°C; the timing for disassembling the outer mold 110 is: disassembling the outer mold 110 when the mold temperature drops to any temperature between 75°C and 85°C.
[0051] For Example 1, after demolding, the composite material product 120 is subjected to ultrasonic non-destructive testing, and the overall interior of the product is free of defects such as pores, dispersion, and stratification. The composite material product 120 is sampled for physical and chemical property testing, and its fiber volume content is in the range of 57% to 60%, and the porosity is less than 1%.
[0052] Comparative Example 1
[0053] Step S1, providing a mold, the mold comprising a core mold and an outer mold, wherein the core mold is the same as the core film provided by the present invention, and the outer mold is different from the outer mold provided by the present invention in that the outer mold provided in Comparative Example 1 does not have a groove, and Comparative Example 1 does not involve a metal pad and an elastic buffer in the preparation process of the product;
[0054] Step S2, preparing a high temperature system prepreg, using carbon fiber and bismaleimide resin as raw materials to prepare a high temperature system prepreg, and the single layer thickness of the high temperature system prepreg is the same as that of Example 1;
[0055] Step S3, using the prepared high temperature system prepreg to lay on the core mold for forming, the laying thickness and laying angle are the same as those in Example 1;
[0056] Step S4, assembling the mold for cold mold closing and high temperature curing.
[0057] Step S5, demoulding the product. Specifically, after the temperature of the mold drops to room temperature, the outer mold is removed to obtain the product.
[0058] In Comparative Example 1, after demoulding, ultrasonic nondestructive testing was performed on the product, and diffuse defects and interlayer peeling and delamination defects were found in the interlayer interface of the product flange.
[0059] In the preparation method of the composite product 120 provided by the present invention, for the composite product 120 with a flange 122, in terms of mold design, a groove 111 is provided, and a high-temperature resistant elastic buffer body 130 is provided in the groove 111 as a buffer, thereby avoiding the outer mold 110 from squeezing the flange 122 during the cooling stage after high-temperature curing. In terms of demolding process control, the release timing of the pressure bolts and the timing of disassembling the outer mold 110 are controlled, thereby effectively solving the defect problem of the flange 122 when the composite product 120 is prepared using a high-temperature resin system as a raw material, thereby ensuring the internal quality of this type of composite product 120.
[0060] The present invention also provides a composite material product 120, which is prepared using the above-mentioned mold, or prepared using the above-mentioned composite material preparation method. The composite material product 120 includes an integrally formed product body 121 and a flange 122.
[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: include: A core mold, an outer mold, an elastic buffer body and a metal pad, wherein when the mold is in a mold-closing state, the outer mold is positioned outside the core mold, and the surface of the outer mold facing the core mold and the surface of the core mold facing the outer mold form a mold cavity, and the mold cavity is used to form a composite material product, and the composite material product includes an integrally formed product body and a flange; The mold cavity comprises a main body cavity and a flanging cavity which are connected to each other, the main body cavity is used to form the product body, and the flanging cavity is used to form the flanging; The outer mold is provided with a groove, one end of the flange cavity away from the main body cavity is directly opposite to the groove, and the shapes of the metal pad and the elastic buffer body both correspond to the groove; During the preparation of the composite material product, the groove is used to arrange the metal pad in the pre-compacting step, and the groove is used to arrange the elastic buffer in the high-temperature curing step.
2. The mold according to claim 1, characterized in that: In the high temperature curing step, the elastic buffer body is fixed in the groove by bonding.
3. The mold according to claim 1, characterized in that: The glass transition temperature of the composite material product is not less than 200° C., the material of the outer mold includes metal, and the material of the elastic buffer body includes high-temperature resistant silicone.
4. The mold according to claim 1, characterized in that: The thickness of the main body cavity is the same as that of the flange cavity. In the direction perpendicular to the thickness of the flange cavity, the size of the groove is twice the thickness of the flange cavity. In the direction of the thickness of the flange cavity, the size of the groove is larger than the thickness of the flange cavity, and the difference between the size of the groove and the thickness of the flange cavity is in the range of 5mm to 10mm.
5. A method for preparing a composite material product, characterized in that: include: A mold according to any one of claims 1 to 4 is provided, wherein the mold comprises a core mold, an outer mold, an elastic buffer body and a metal pad; Preparing high temperature system prepreg; Laying the high temperature system prepreg on the side of the core mold; Placing the metal pad in the groove of the outer mold, and assembling the outer mold on the outer side of the core mold by using pressure bolts to apply pressure, so as to pre-compact the high temperature system prepreg; Release the pressure bolt to remove the outer mold from the core mold, use the elastic buffer body to replace the metal pad, and place the elastic buffer body in the groove; The outer mold is assembled on the outer side of the core mold by using the pressure bolts to apply pressure to achieve cold mold closing; The high temperature system prepreg is cured at high temperature to form a composite material product.
6. The method for preparing a composite material product according to claim 5, characterized in that: The high-temperature curing step includes: heating the high-temperature system prepreg in the mold cavity to the glass transition temperature, continuing heating for a preset time and then stopping heating, releasing the pressure bolts before the mold cools to room temperature, and disassembling the outer mold after releasing the pressure bolts to demold the composite product.
7. The method for preparing a composite material product according to claim 6, characterized in that: When the temperature of the mold drops to (T g / 2-T1)℃, release the pressure bolt, where T g is the glass transition temperature of the high temperature system prepreg, and T1 is in the range of 10°C to 20°C.
8. The method for preparing a composite material product according to claim 6 or 7, characterized in that: When the temperature of the mold drops to T g / 3±5℃, dismantle the outer mold to demould the composite product, wherein T g is the glass transition temperature of the high temperature system prepreg.
9. A composite material product, characterized in that: The composite material product is prepared using the mold as described in any one of claims 1 to 4, or is prepared using the method for preparing a composite material product as described in any one of claims 5 to 8, wherein the composite material product comprises an integrally formed product body and a flange.