CN118544612A - A method for forming a multi-cavity carbon fiber bracket - Google Patents

Abstract

The present invention provides a molding method of a multi-cavity structure carbon fiber bracket, which relates to the field of fiber composite molding, including: 1) making a rubber soft mold according to the inner cavity profile of the target bracket, the shape and size of the rubber soft mold being adapted to the inner cavity structure of the multi-cavity structure carbon fiber bracket; 2) first laying a part of the prepreg layer on each of the prepared rubber soft molds and fixing it with a tooling, and then laying the annular flange layer to obtain a rubber mold; 3) sequentially positioning and installing the rubber mold, the core mold and the upper mold on the lower mold of the bracket molding mold, closing the mold to make a bag; 4) curing the prepreg, and demoulding after curing; 5) fine-machining the rough bracket obtained by demoulding according to the target bracket structure requirements to obtain the target bracket. The present invention adopts an autoclave process to realize the integrated molding of the multi-cavity structure bracket, which effectively improves the internal quality of the bracket while reducing the production cost.

Description

A method for forming a multi-cavity carbon fiber bracket

Technical Field

The invention relates to the technical field of fiber composite molding, and in particular to a molding method of a multi-cavity structure carbon fiber bracket.

Background Art

Carbon fiber brackets are usually used to replace metal parts with the same structure and connect the main body with other components. They are widely used in composite aviation and aerospace fields.

Multi-cavity structural carbon fiber parts are usually manufactured using RTM, co-bonding or bonding assembly processes. The internal quality of parts molded by RTM and co-bonding processes is poor, and the bonding assembly process has a large assembly workload, increased product weight, complex procedures and high costs.

Summary of the invention

The purpose of the present invention is to provide a molding method for a multi-cavity structure carbon fiber bracket, which utilizes a rubber soft mold to realize the autoclave integrated molding of the multi-cavity structure carbon fiber composite material bracket. The soft mold can not only enhance the internal quality of the parts, increase the parts molding efficiency, and reduce the manufacturing process, but also can be reused.

To achieve the above object, the present invention proposes the following technical solutions:

A method for forming a multi-cavity carbon fiber bracket comprises the following steps:

1) Making a soft mold: making a plurality of rubber soft molds according to the inner cavity profile of the target stent, wherein the shape and size of the rubber soft molds are adapted to the inner cavity structure of the multi-cavity carbon fiber stent;

2) Prepreg paving: First, partially paving each of the obtained rubber soft molds and fixing them with a positioning tool to obtain a pre-rubber mold; then paving an annular flanged layer of prepreg on the inner circle of the pre-rubber mold to obtain a rubber mold; wherein the prepreg layer paved on each rubber soft mold and the annular flanged layer together constitute the target bracket structure;

3) Mold closing and bag making: the rubber mold, the core mold and the upper mold are positioned and installed on the lower mold of the bracket forming mold in sequence, and a sealing strip is laid on the outer periphery of the bracket forming mold after the mold closing and the bag is made;

4) Curing and demoulding: Curing the prepreg according to the preset autoclave curing process, and demoulding after curing;

5) Processing: according to the structural requirements of the target bracket, the rough bracket obtained by demoulding is subjected to hole making and cutting to obtain the target bracket.

Furthermore, the process of making a plurality of rubber soft molds according to the inner cavity profile of the target stent in step 1) is as follows:

Taking the inner cavity surface of the target stent as a reference, determine the shapes of each soft mold to be produced;

Taking the inner cavity profile of the target stent as a reference and combining the expansion and contraction of the rubber, a female mold forming mold is manufactured for any soft mold, wherein the female mold forming mold includes an upper mold and a lower mold;

The soft mold is formed by using a hot autoclave, and the unvulcanized rubber is filled into the female mold, and then the female mold is locked by bolts to make the bag and solidify;

Demoulding, remove the bolts to separate the upper and lower moulds to obtain a soft mould.

Furthermore, the positioning tool in step 2) includes: a metal frame, a plurality of upper gaskets, a plurality of lower gaskets and a plurality of bolt assemblies;

The metal frame is used to provide a mounting frame for each soft mold paved with prepreg layers, and the upper gasket and the lower gasket are used to fix the mounting frame with a bolt assembly to form a pre-rubber mold of the target structure.

Furthermore, in the step 3), a plurality of groups of lower mold positioning guide holes are symmetrically arranged along the relative sides of the lower mold of the bracket forming mold, and a plurality of groups of positioning holes corresponding to the positions of the lower mold positioning guide holes are arranged on the positioning tooling, and then the lower mold positioning guide holes are matched and fastened with the corresponding positioning holes to complete the fixation of the rubber mold on the lower mold of the bracket forming mold.

Furthermore, in the step 3), a plurality of lower mold positioning grooves are provided on the lower mold of the bracket forming mold, and the plurality of lower mold positioning grooves are arranged in a ring shape within a plurality of symmetrically arranged groups of lower mold positioning guide holes; a plurality of core mold positioning bosses are provided on the side surface of the core mold opposite to the lower mold, and the core mold positioning bosses are adapted in size to the lower mold positioning grooves and have corresponding positions one by one, and then when the core mold positioning bosses are matched with the lower mold positioning grooves for positioning, the core mold is fixed on the lower mold of the bracket forming mold and on the inner side of the rubber mold.

Furthermore, in the step 3), a plurality of core mold positioning grooves are provided on the side of the core mold of the bracket forming mold away from the lower mold, and the core mold positioning grooves are arranged in a ring shape on the surface of the core mold; a plurality of upper mold positioning bosses are provided on the side opposite to the lower mold of the upper mold of the bracket forming mold, and the upper mold positioning bosses are adapted in size to the core mold positioning grooves and have corresponding positions one by one, and then when the upper mold positioning bosses are positioned in coordination with the core mold positioning grooves, the upper mold is fixed on the core mold; and the opposite side of the upper mold close to the core mold completely covers and fits the surface of the prepreg ply laid on the rubber mold.

Furthermore, the unvulcanized rubber is selected to have a hardness of Shore A 40-80 and an expansion rate of 1%-5%.

Furthermore, the combined rubber expansion and contraction amounts, in the process of making a female mold for any soft mold, the mold cavity is expanded by 2mm-5mm and 0.5mm-3mm in its length direction and thickness direction respectively.

Furthermore, the bag making and curing process when making the rubber soft mold is as follows:

For the locked female mold, use pressure-sensitive tape to close the mold seam, then lay auxiliary materials on the entire surface of the mold, make a full bag and put it into the autoclave; the working parameters of the autoclave are: initial pressure 0.6Mpa-1Mpa, heating to 155-195℃, keeping warm for 1-3h, and opening the can after cooling to room temperature after the insulation ends.

Furthermore, the process of curing the prepreg according to the preset autoclave curing process in step 4) is as follows:

After bagging, the stent forming mold is placed in an autoclave, heated to 80℃-100℃ and kept warm for 1-3h. After the insulation is completed, the pressure is increased to 0.5-0.7Mpa, and then the temperature is continued to be raised to 155-195℃ and kept warm for 6-10h. After the insulation is completed, the pressure is released and the can is opened.

It can be seen from the above technical solutions that the technical solutions of the present invention have the following beneficial effects:

The present invention provides a molding method of a carbon fiber bracket with a multi-cavity structure, comprising the following steps: 1) making a soft mold: making a plurality of rubber soft molds according to the inner cavity profile of a target bracket, wherein the shape and size of the rubber soft molds are adapted to the inner cavity structure of the carbon fiber bracket with a multi-cavity structure; 2) prepreg paving: firstly paving a portion of a prepreg ply on each of the prepared rubber soft molds respectively and fixing them with a positioning tool to obtain a pre-rubber mold; then paving an annular flanged ply of the prepreg on the inner circle of the pre-rubber mold to obtain a rubber mold; wherein the prepreg ply and the annular flanged ply laid on each of the rubber soft molds together constitute the target bracket structure; 3) mold closing and bag making: sequentially positioning and installing a rubber mold, a core mold and an upper mold on a lower mold of a bracket forming mold, laying a sealing strip on the periphery of the bracket forming mold after mold closing and making a bag; 4) curing and demoulding: curing the prepreg according to a preset autoclave curing process, and demoulding by opening the can after curing; 5) processing: making holes and cutting the rough bracket obtained by demoulding according to the requirements of the target bracket structure to obtain the target bracket. The present invention adopts the autoclave process to realize the integrated molding of the multi-cavity structure bracket, which effectively improves the internal quality of the bracket and reduces the production cost.

Compared with the prior art, the present invention can not only adopt the autoclave process to realize the integrated molding of the multi-cavity structure bracket, enhance the internal quality of the parts, and reduce the manufacturing process; at the same time, the rubber soft mold manufactured by molding can be reused, reducing the manufacturing cost of the parts and improving the market competitiveness of the product.

It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, may be considered to be part of the inventive subject matter of the present disclosure, provided such concepts are not mutually inconsistent.

The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and/or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG1 is a schematic structural diagram of a target bracket prepared in an embodiment;

FIG2( a ) is a schematic diagram of an L-shaped soft mold of a target bracket manufactured in an embodiment;

FIG2( b ) is a schematic diagram of a square soft mold of a target bracket made in an embodiment;

FIG2( c ) is a schematic diagram of a trapezoidal soft mold of a target bracket manufactured in an embodiment;

3 is a schematic diagram of a female mold forming mold of an L-shaped soft mold of a target bracket manufactured in an embodiment;

Fig. 4 is a schematic diagram of a rubber mold obtained in the embodiment;

FIG5 is a schematic diagram of a stent forming mold of the target stent of the embodiment.

Among them: 1-L-type soft mold, 2-square soft mold, 3-trapezoidal soft mold, 4-upper mold, 5-lower mold, 6-hexagon socket bolt, 7-pin, 8-upper gasket, 9-lower gasket, 10-hexagon countersunk screw, 11-metal frame, 12-hexagon socket cup head screw, 13-pin, 14-bracket forming mold upper mold, 15-core mold, 16-bracket forming mold lower mold, 17-upper mold positioning boss, 18-core mold positioning groove, 19-core mold positioning boss, 20-lower mold positioning groove, 21-lower mold positioning guide hole.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meaning understood by people with general skills in the field to which the present invention belongs.

The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "a", "an" or "the" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" cover the features, wholes, steps, operations, elements and/or components listed after "include" or "comprise", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and/or their collections. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

Based on the current situation that multi-cavity structure carbon fiber parts are usually manufactured by RTM, co-bonding or bonding assembly process, the process is complicated and cannot be manufactured as a whole, the present invention proposes a molding method of a multi-cavity structure carbon fiber bracket that can be manufactured as a whole, and a rubber soft mold is used to realize the autoclave one-piece molding of the multi-cavity structure carbon fiber composite material bracket, which reduces the manufacturing process and improves product quality.

The method for forming a multi-cavity carbon fiber stent disclosed in the present invention comprises the following steps:

1) Making a soft mold: making a plurality of rubber soft molds according to the inner cavity profile of the target stent, wherein the shape and size of the rubber soft molds are adapted to the inner cavity structure of the multi-cavity carbon fiber stent;

2) Prepreg paving: First, partially paving each of the obtained rubber soft molds and fixing them with a positioning tool to obtain a pre-rubber mold; then paving an annular flanged layer of prepreg on the inner circle of the pre-rubber mold to obtain a rubber mold; wherein the prepreg layer paved on each rubber soft mold and the annular flanged layer together constitute the target bracket structure;

3) Mold closing and bag making: the rubber mold, the core mold and the upper mold are positioned and installed on the lower mold of the bracket forming mold in sequence, and a sealing strip is laid on the outer periphery of the bracket forming mold after the mold closing and the bag is made;

4) Curing and demoulding: Curing the prepreg according to the preset autoclave curing process, and demoulding after curing;

5) Processing: according to the structural requirements of the target bracket, the rough bracket obtained by demoulding is subjected to hole making and cutting to obtain the target bracket.

The process of making a plurality of rubber soft molds according to the inner cavity profile of the target bracket in the above step 1) is as follows: taking the inner cavity profile of the target bracket as a reference, determining the shape of each soft mold to be made; taking the inner cavity profile of the target bracket as a reference, combining the expansion and contraction of the rubber, making a female mold forming mold for any soft mold, wherein the female mold forming mold includes an upper mold and a lower mold; using an autoclave to form the soft mold, filling the female mold forming mold with unvulcanized rubber, and then locking the female mold forming mold by bolts to make bags and solidify; demolding, removing the bolts to separate the upper and lower molds, and obtaining the soft mold; wherein, when making the female mold forming mold, combining the expansion and contraction of the rubber, in the process of making the female mold forming mold for any soft mold, the mold cavity is expanded by 2mm-5mm and 0.5mm-3mm in its length direction and thickness direction respectively; the unvulcanized rubber is selected to have a hardness of Shore A40-80 and an expansion rate of 1%-5%.

The following is a further detailed introduction to the molding method of the multi-cavity carbon fiber bracket disclosed in the present invention in conjunction with the specific embodiments shown in the accompanying drawings. As shown in FIG1 , the multi-cavity carbon fiber bracket is a ring structure with flanges, which includes eight cavities. The manufacturing material is made of bismuth resin carbon fiber unidirectional tape prepreg, which is integrally molded in an autoclave. The internal quality of the bracket is guaranteed by the expansion and pressurization of the rubber soft mold filled into the inner cavity. The specific molding process is as follows:

Soft mold design: According to Figures 1 and 2(a)-2(c), the soft molds required for the target bracket are mainly three types: L-shaped soft mold 1, square soft mold 2 and trapezoidal soft mold 3. When designing, for example, for the L-shaped soft mold 1, first use the corresponding inner cavity profile of the target bracket as a reference. The upper mold 4 and the lower mold 5 of the female mold forming mold are shown in Figure 3 and are positioned and connected by hexagonal pins 7 and bolts 6. The mold cavity is enlarged by 5mm and 2mm in length and thickness directions respectively according to the rubber expansion and contraction.

Soft mold molding: first, fill the unvulcanized rubber into the inner cavity of the upper mold 4 of the female mold molding mold and press it tightly. The rubber with a hardness of Shore A60 and an expansion rate of 3.29% is selected. The lower mold 5 of the female mold molding mold is locked by bolts 6 and pins 7. Use pressure-sensitive tape to stick to the mold seam to ensure the internal quality of the expanded rubber soft mold; lay auxiliary materials on the surface of the female mold molding mold as a whole, make a full bag and put it into the autoclave, initially pressurize 0.6Mpa-1Mpa, heat to 155-195℃, keep warm for 1-3h, and start cooling after the insulation ends. When it drops to room temperature, open the can, remove the auxiliary materials, and complete demolding with bolts and pins; in the embodiment, initially pressurize 0.8Mpa, heat to 175℃, and keep warm for 2h.

Laying: The target bracket is formed by first completing half of the laying on the rubber soft mold, and then fixing it with a positioning tool; the positioning tool includes: a metal frame, a plurality of upper gaskets, a plurality of lower gaskets and a plurality of bolt assemblies; the metal frame is used to provide a mounting frame for each soft mold paved with prepreg layers, and the upper gaskets and the lower gaskets are used to fix the mounting frame with bolt assemblies to form a pre-rubber mold of the target structure; in the embodiment shown in Figure 4, the positioning tool includes ten upper gaskets 8 and four lower gaskets 9, and the upper gaskets 8, the lower gaskets 9 and the metal frame 11 fix the eight soft molds with hexagonal countersunk screws 10 and hexagon socket head screws 12 to obtain a pre-rubber mold; after the fixation is completed, twisted wire is manually filled at the R angle to ensure the quality of the vertical reinforcement, and then the laying of the remaining half of the layer is completed, that is, the annular flanged layer of prepreg is laid on the inner circle of the pre-rubber mold to obtain a rubber mold, as shown in Figure 4.

Mold closing: As shown in FIG5 , a plurality of groups of lower mold positioning guide holes 21 are symmetrically arranged along the opposite sides of the lower mold 16 of the bracket forming mold, and a plurality of groups of positioning holes corresponding to the positions of the lower mold positioning guide holes 21 are arranged on the positioning tooling. After the prepreg is laid, the rubber mold is fixed to the lower mold 16 of the bracket forming mold through the pins 13 and the lower mold positioning guide holes 21; a plurality of lower mold positioning grooves 20 are arranged on the lower mold 16 of the bracket forming mold, and the plurality of lower mold positioning grooves 20 are arranged in a ring shape in the plurality of groups of the lower mold positioning guide holes 21 that are symmetrically arranged; a plurality of core mold positioning bosses 19 are arranged on the side opposite to the lower mold on the core mold 15, and the core mold positioning bosses 19 are adapted in size to the lower mold positioning grooves 20 and correspond in position one by one, and then when the core mold positioning bosses 19 are positioned in cooperation with the lower mold positioning grooves 20, on the lower mold 16 of the bracket forming mold and on the inner side of the rubber mold A core mold 15 is inserted, and the internal annular size of the part is guaranteed by the core mold 15; a plurality of core mold positioning grooves 18 are arranged on the side of the core mold 15 of the bracket forming mold away from the lower mold, and the core mold positioning grooves 18 are arranged in a ring shape on the surface of the core mold 15; a plurality of upper mold positioning bosses 17 are arranged on the opposite side of the upper mold 14 of the bracket forming mold close to the lower mold, and the upper mold positioning bosses 17 are adapted in size to the core mold positioning grooves 18 and have a one-to-one corresponding position, and then when the upper mold positioning bosses 17 and the core mold positioning grooves 18 are positioned in cooperation, the upper mold is fixed on the core mold 15; and the opposite side of the upper mold close to the core mold 15 completely covers and fits the surface of the prepreg layer laid on the rubber mold; that is, the target bracket is ensured by the lower mold 16 and the engraved line of the bracket forming mold to ensure the surface quality and size of the lower flange of the part, and the upper mold 14 of the bracket forming mold is used to ensure the surface quality of the upper flange of the target bracket.

Bag making: After the mold is closed, a sealing strip is laid outside the upper margin area of the lower mold 16 of the bracket forming mold and the bag is made.

Curing and demoulding: After the bag making is completed, the bag is placed in an autoclave and heated to 80-100°C for 1-3 hours. After the insulation, the pressure is increased to 0.5-0.7Mpa, and then the temperature is increased to 155-195°C for 6-10 hours. After the insulation, the pressure is reduced to room temperature, the can is opened, and the mold is demolded. The removed soft mold can be kept for continued use. In the embodiment, the autoclave is heated to 90°C for 1 hour, and the pressure is increased to 0.6Mpa after the insulation, and then the temperature is increased to 180°C for 8 hours.

Processing: After demoulding, holes are made and cut according to the size and hole position markings on the target bracket to finally complete the production of parts.

The core of the molding method of the multi-cavity structure carbon fiber bracket disclosed in the present invention is to directly mold the multi-cavity structure bracket as a whole by using the autoclave process through designing and manufacturing soft molds, without the need for gluing and assembly, thereby improving assembly efficiency; at the same time, the soft mold is used during molding to ensure the multi-cavity structure quality of the target bracket, and the soft mold can be reused, further reducing the manufacturing cost of the bracket.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims (10)

1. A method for forming a multi-cavity carbon fiber stent, characterized in that it comprises the following steps: 1) Making a soft mold: making a plurality of rubber soft molds according to the inner cavity profile of the target stent, wherein the shape and size of the rubber soft molds are adapted to the inner cavity structure of the multi-cavity carbon fiber stent; 2) Prepreg paving: First, partially paving each of the obtained rubber soft molds and fixing them with a positioning tool to obtain a pre-rubber mold; then paving an annular flanged layer of prepreg on the inner circle of the pre-rubber mold to obtain a rubber mold; wherein the prepreg layer paved on each rubber soft mold and the annular flanged layer together constitute the target bracket structure; 3) Mold closing and bag making: the rubber mold, the core mold and the upper mold are positioned and installed on the lower mold of the bracket forming mold in sequence, and a sealing strip is laid on the outer periphery of the bracket forming mold after the mold closing and the bag is made; 4) Curing and demoulding: Curing the prepreg according to the preset autoclave curing process, and demoulding after curing; 5) Processing: according to the structural requirements of the target bracket, the rough bracket obtained by demoulding is subjected to hole making and cutting to obtain the target bracket. 2. The molding method of a multi-cavity carbon fiber stent according to claim 1, characterized in that the process of making a plurality of rubber soft molds according to the target stent inner cavity profile in step 1) is: Taking the inner cavity surface of the target stent as a reference, determine the shapes of each soft mold to be produced; Taking the inner cavity profile of the target stent as a reference and combining the expansion and contraction of the rubber, a female mold forming mold is manufactured for any soft mold, wherein the female mold forming mold includes an upper mold and a lower mold; The soft mold is formed by using a hot autoclave, and the unvulcanized rubber is filled into the female mold, and then the female mold is locked by bolts to make the bag and solidify; Demoulding, remove the bolts to separate the upper and lower moulds to obtain a soft mould. 3. The molding method of a multi-cavity carbon fiber bracket according to claim 1, characterized in that the positioning tool in step 2) comprises: a metal frame, a plurality of upper gaskets, a plurality of lower gaskets and a plurality of bolt assemblies; The metal frame is used to provide a mounting frame for each soft mold paved with prepreg layers, and the upper gasket and the lower gasket are used to fix the mounting frame with a bolt assembly to form a pre-rubber mold of the target structure. 4. The molding method of a multi-cavity structure carbon fiber bracket according to claim 3 is characterized in that in the step 3), a plurality of groups of lower mold positioning guide holes are symmetrically arranged along the relative sides of the lower mold of the bracket molding mold, and a plurality of groups of positioning holes corresponding to the positions of the lower mold positioning guide holes are arranged on the positioning tooling, and then the lower mold positioning guide holes are matched and fastened with the corresponding positioning holes to complete the fixation of the rubber mold on the lower mold of the bracket molding mold. 5. The molding method of a multi-cavity structure carbon fiber bracket according to claim 4 is characterized in that, in the step 3), a plurality of lower mold positioning grooves are arranged on the lower mold of the bracket molding mold, and the plurality of lower mold positioning grooves are arranged in a ring shape within a plurality of symmetrically arranged groups of lower mold positioning guide holes; a plurality of core mold positioning bosses are arranged on the side surface of the core mold opposite to the lower mold, and the core mold positioning bosses are adapted in size to the lower mold positioning grooves and have a one-to-one correspondence in position, and then when the core mold positioning bosses are matched with the lower mold positioning grooves for positioning, the core mold is fixed on the lower mold of the bracket molding mold and on the inner side of the rubber mold. 6. The molding method of a multi-cavity structure carbon fiber bracket according to claim 4 is characterized in that, in the step 3), a plurality of core mold positioning grooves are provided on the side of the core mold of the bracket molding mold away from the lower mold, and the core mold positioning grooves are arranged in a ring shape on the surface of the core mold; a plurality of upper mold positioning bosses are provided on the side opposite to the lower mold of the upper mold of the bracket molding mold, and the upper mold positioning bosses are adapted in size to the core mold positioning grooves and have one-to-one corresponding positions, and then when the upper mold positioning bosses are matched and positioned with the core mold positioning grooves, the upper mold is fixed on the core mold; and the opposite side of the upper mold close to the core mold completely covers and fits the surface of the prepreg ply laid on the rubber mold. 7. The molding method of a multi-cavity structure carbon fiber bracket according to claim 2, characterized in that the unvulcanized rubber is selected from rubber with a hardness of Shore A40-80 and an expansion rate of 1%-5%. 8. The molding method of a multi-cavity carbon fiber bracket according to claim 7 is characterized in that the combined rubber expansion and contraction amount, in the process of making a negative mold molding mold for any soft mold, the mold cavity is expanded by 2mm-5mm and 0.5mm-3mm in its length direction and thickness direction respectively. 9. The method for forming a multi-cavity carbon fiber bracket according to claim 2, characterized in that the bag making and curing process is: For the locked female mold, use pressure-sensitive tape to close the mold seam, then lay auxiliary materials on the entire surface of the mold, make a full bag and put it into the autoclave; the working parameters of the autoclave are: initial pressure 0.6Mpa-1Mpa, heating to 155-195℃, keeping warm for 1-3h, and opening the can after cooling to room temperature after the insulation ends. 10. The method for forming a multi-cavity carbon fiber bracket according to claim 1, characterized in that the process of curing the prepreg according to a preset autoclave curing process in step 4) is: After bagging, the stent forming mold is placed in an autoclave, heated to 80℃-100℃ and kept warm for 1-3h. After the insulation is completed, the pressure is increased to 0.5-0.7Mpa, and then the temperature is continued to be raised to 155-195℃ and kept warm for 6-10h. After the insulation is completed, the pressure is released and the can is opened.