A method for manufacturing a carbon fiber hollow pipe

Abstract

The application discloses a manufacturing method of carbon fiber hollow pipe, which comprises the following steps: first, preparation, material preparation: preparing impregnated resin glass fiber felt, glass fiber surface felt, 3K carbon fiber upper shell, 3K carbon fiber lower shell, core material, vacuum bag, high-temperature-resistant preservative film and a plurality of UD carbon fiber cloths, wherein the UD carbon fiber cloth is provided with a plurality of air holes; equipment preparation: preparing a pre-vacuum device, a preheating jig and a PCM mold forming mold, wherein the preheating temperature of the preheating jig is lower than the mold temperature of the PCM mold forming mold; second, preforming; third, shaping; fourth, preheating; fifth, PCM mold forming. By providing the UD carbon fiber cloth with a plurality of air holes, the air exhaust performance of the UD carbon fiber cloth is improved, the impregnated resin glass fiber felt and the glass fiber surface felt can both play a role in air guiding, the high-temperature-resistant preservative film is a releasable film, which is convenient to remove and reduces the bulge generation rate of the carbon fiber hollow pipe.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber hollow tubing, and in particular to a method for manufacturing carbon fiber hollow tubing. Background Technology

[0002] Carbon fiber hollow tubing is a type of hollow tubing that is lighter than solid tubing. It is commonly used in products such as bicycles and automobiles, including automobile products such as carbon fiber roll cages.

[0003] In existing technologies, carbon fiber hollow tubes consist of several layers of UD carbon fiber cloth inside and an exposed 3K carbon fiber outer shell. This layered structure, where the 3K carbon fiber outer shell and UD carbon fiber cloth layers are directly bonded, is prone to bulging during manufacturing. Bulging affects the product's appearance and quality. Common causes of bulging include: 1. Poor venting performance between the 3K carbon fiber outer shell and the UD carbon fiber cloth layers, causing gas to accumulate between them and bulge, resulting in localized protrusions in the 3K carbon fiber outer shell; 2. Inadequate bonding between layers of UD carbon fiber cloth during stacking, or excessively high mold temperatures. When gas from the inner layers of the UD carbon fiber cloth reaches the middle, the outermost layers have hardened, trapping the gas and preventing its escape. This poor venting performance between multiple UD carbon fiber cloth layers indirectly leads to localized protrusions in the 3K carbon fiber outer shell. Therefore, reducing the bulging rate of carbon fiber hollow tubes is a key research focus in the industry.

[0004] Therefore, it is necessary to design a new technical solution to address the above problems. Summary of the Invention

[0005] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide a method for manufacturing carbon fiber hollow tubing. This method improves the air venting performance of the UD carbon fiber cloth by providing several vent holes. Both the resin-impregnated glass fiber mat and the glass fiber surface mat serve as air guides, allowing internal gases to be expelled from the carbon fiber hollow tubing through these guides. This prevents air from accumulating between the UD carbon fiber cloth and the 3K carbon fiber upper and lower shells, and also ensures good contact with the UD carbon fiber. The combination of UD carbon fiber cloth and 3K carbon fiber cloth does not affect the structural strength of either UD carbon fiber cloth or 3K carbon fiber cloth. Furthermore, the high-temperature resistant food preservation film covering makes the surface of the UD carbon fiber cloth stacked smoother and flatter, facilitating the stacking of UD carbon fiber cloth. The high-temperature resistant food preservation film is also a release film, making it easy to remove. In addition, the positive and negative pressure air sources work together to press the UD carbon fiber cloth and 3K carbon fiber cloth tightly against the mold cavity wall of the PCM molding die, resulting in better shaping effect of the pre-molded body after preheating. This reduces the bulging rate of carbon fiber hollow tubes and improves the yield of carbon fiber hollow tubes.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for manufacturing a carbon fiber hollow tube includes the following steps:

[0008] The first step is preparation, including the following materials: resin-impregnated glass fiber mat, glass fiber surface mat, 3K carbon fiber upper shell, 3K carbon fiber lower shell, core material, vacuum bag, high-temperature resistant food preservation film, and several pieces of UD carbon fiber cloth, wherein the UD carbon fiber cloth has several air vents; and the following equipment: a pre-vacuuming device, a preheating fixture, and a PCM molding die, wherein the preheating temperature of the preheating fixture is lower than the die temperature of the PCM molding die.

[0009] The second step is pre-molding. First, the core material is inserted into the vacuum bag. Then, breathable cotton is placed in the vacuum bag, close to the core material. Next, the two ends of the vacuum bag are sealed by applying putty. Then, the vacuum bag is tested for air leakage. Then, the vacuum bag is straightened on the core material. Next, the high-temperature resistant plastic wrap is wrapped around the vacuum bag by pressing and wrapping it once. Finally, several pieces of UD carbon fiber cloth are stacked and wrapped around the high-temperature resistant plastic wrap to form several layers of UD carbon fiber cloth.

[0010] The third step is shaping. First, the resin-impregnated glass fiber mat is layered and wrapped around the UD carbon fiber cloth. Then, the glass fiber surface mat is wrapped around the resin-impregnated glass fiber mat. Next, the 3K carbon fiber upper shell and 3K carbon fiber lower shell are spliced ​​together and wrapped around the glass fiber surface mat to form a preform. Finally, the preform is placed in a pre-vacuum device for pre-vacuuming to initially press the preform together.

[0011] The fourth step is preheating. After attaching the nozzles to the ends of the preform, place it into the preheating fixture to preheat the preform.

[0012] The fifth step is PCM compression molding. The preheated preform is placed into a PCM compression molding mold for PCM compression molding. After PCM compression molding, the core material, vacuum bag, and high-temperature resistant plastic wrap are removed to obtain carbon fiber hollow tubing. The PCM compression molding mold is equipped with a positive pressure air source and a negative pressure air source. The positive pressure air source is used to expand the vacuum bag outward, and the negative pressure air source is used to draw the 3K carbon fiber upper shell and 3K carbon fiber lower shell outward.

[0013] As a preferred embodiment, in the material preparation, the UD carbon fiber cloth is punctured and perforated using a perforating roller to form the ventilation holes. The vacuum bag is humidified to ensure that the vacuum bag is soft and facilitates the insertion of the core material.

[0014] As a preferred method, the air inside the vacuum bag should be removed before performing leak detection to improve the accuracy of leak detection.

[0015] As a preferred solution, after wrapping the high-temperature resistant plastic wrap, firstly, air ducts are fitted on both ends of the core material to prevent air leakage at the ports. Then, masking tape is applied to the outside of the air ducts to prevent them from falling off. Finally, another layer of high-temperature resistant plastic wrap is wrapped on the surface of the masking tape to prevent the masking tape from sticking to the UD carbon fiber cloth.

[0016] As a preferred option, when a layer of UD carbon fiber cloth is covered by one piece of UD carbon fiber cloth, the resin-impregnated glass fiber mat is one piece. When a layer of UD carbon fiber cloth is covered by two pieces of UD carbon fiber cloth, the two ends of the two pieces of UD carbon fiber cloth are spliced ​​together accordingly. Correspondingly, the resin-impregnated glass fiber mat is two pieces. The overlapping method is reasonably selected according to the cross-sectional area of ​​the core material to facilitate overlapping and covering.

[0017] As a preferred option, when stacking UD carbon fiber fabric, a pad is placed at the gripping position of the core material to prevent the core material from bending downwards.

[0018] As a preferred embodiment, the preheating temperature of the preheating fixture is 50-70 degrees Celsius, and the mold temperature of the PCM molding die is 130-150 degrees Celsius.

[0019] As a preferred embodiment, the PCM molding die includes an upper die and a lower die, which are sealed together so that the preheated preform is located in a sealed cavity. The blowing end of the positive pressure air source is connected to a nozzle, and the negative pressure air source is connected to the sealed cavity. The sealed connection between the upper die and the lower die can prevent air leakage from the sealed cavity where the preheated preform is located.

[0020] As a preferred embodiment, the air intake end of the negative pressure air source is equipped with an air source silencer. The air source silencer can prevent the air intake end of the negative pressure air source from being blocked by resin. By blowing or replacing the air source silencer, it can be ensured that the air intake end of the negative pressure air source is not blocked, which is convenient to use.

[0021] As a preferred embodiment, the resin-impregnated glass fiber mat is an epoxy resin-impregnated glass fiber mat, and the glass fiber surface mat is a wet-laid nonwoven E glass fiber surface mat.

[0022] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution:

[0023] The main advantage is that by incorporating several vents into the UD carbon fiber cloth, its air-exhaust performance is improved. Both the resin-impregnated glass fiber mat and the glass fiber surface mat act as air guides, allowing internal gases to escape from the carbon fiber hollow tube through these guides. This prevents air from accumulating between the UD carbon fiber cloth and the 3K carbon fiber upper and lower shells, and ensures good bonding between the cloth and the 3K carbon fiber cloth without affecting the UD carbon fiber structure. The structural strength of the UD carbon fiber cloth and 3K carbon fiber cloth; and the high-temperature resistant food preservation film covering makes the surface of the UD carbon fiber cloth stacking smoother and flatter, which is convenient for the stacking of UD carbon fiber cloth. Moreover, the high-temperature resistant food preservation film is a release film, which is easy to remove; in addition, the positive pressure air source and the negative pressure air source together adhere the UD carbon fiber cloth and 3K carbon fiber cloth to the mold cavity wall of the PCM molding die, which makes the pre-formed body shaping effect better after preheating; reduce the bulging rate of carbon fiber hollow tubes and improve the yield of carbon fiber hollow tubes.

[0024] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the molding process of a carbon fiber hollow tube according to a preferred embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the UD carbon fiber cloth according to a preferred embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the general structure of the pre-vacuuming device according to a preferred embodiment of the present invention;

[0028] Figure 4 This is a perspective view of a preheating fixture according to a preferred embodiment of the present invention;

[0029] Figure 5 This is a perspective view of a PCM compression molding die according to a preferred embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the installation of the first sealing ring according to a preferred embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the installation of the ejection mechanism according to a preferred embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the installation of the air source silencer according to a preferred embodiment of the present invention;

[0033] Figure 9 This is a schematic diagram of a product application according to a preferred embodiment of the present invention.

[0034] Explanation of reference numerals in the attached diagram:

[0035] 10. Core material 20. Vacuum bag

[0036] 30. High-temperature resistant food preservation film; 40. UD carbon fiber cloth

[0037] 41. Ventilation holes 50. Resin-impregnated fiberglass mat

[0038] 60. Fiberglass surface mat; 71. 3K carbon fiber upper shell

[0039] 72. 3K carbon fiber lower shell; 80. Pre-vacuum device

[0040] 81. Air bag; 90. Preheating fixture

[0041] 100. PCM compression molding die; 1001. Mold cavity

[0042] 1002, Groove; 1003, Positive pressure air source interface

[0043] 1004, Negative pressure air source interface; 110, Air source silencer.

[0044] 120, Insert 130, First sealing ring

[0045] 140. Ejection mechanism; 141. Ejector rod

[0046] 142. Ejector block; 143. Sealing block

[0047] 150. Second sealing ring. Detailed Implementation

[0048] First, it should be noted that in the description of this invention, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Please refer to Figures 1 to 9 As shown, it illustrates a method for manufacturing a carbon fiber hollow tube according to a preferred embodiment of the present invention, comprising the following steps:

[0050] Step 1, Preparation: Materials preparation: Prepare resin-impregnated glass fiber mat 50, glass fiber surface mat 60, 3K carbon fiber upper shell 71, 3K carbon fiber lower shell 72, core material 10, vacuum bag 20, high-temperature resistant food preservation film 30, and several pieces of UD carbon fiber cloth 40, wherein the UD carbon fiber cloth 40 has several air vents; Equipment preparation: Prepare a pre-vacuum device 80, a preheating fixture 90, and a PCM molding die 100, wherein the preheating temperature of the preheating fixture 90 is lower than the die temperature of the PCM molding die 100.

[0051] Specifically, in the material preparation, the UD carbon fiber cloth 40 is punctured and perforated using a perforating roller to form the ventilation holes 41. Several ventilation holes are evenly distributed on the UD carbon fiber cloth 40. The vacuum bag 20 is humidified to ensure that the vacuum bag 20 is soft and easy to insert the core material 10. The operating temperature and humidity of the vacuum bag 20 must be controlled at 24±3℃ and less than 75%RH. The preheating temperature of the preheating fixture 90 is 50-70 degrees Celsius, and the mold temperature of the PCM molding die 100 is 130-150 degrees Celsius.

[0052] In this embodiment, the resin-impregnated glass fiber mat 50 is an epoxy resin-impregnated glass fiber mat, which is a known material and can be purchased from Heyuan Xuanyang Fiber Materials Technology Co., Ltd. Epoxy resin-impregnated glass fiber mat is typically black. The glass fiber surface mat 60 is a wet-laid nonwoven E glass fiber surface mat 60, which is a known material and is compatible with various resins. It can be purchased from Technical Fibre Products Ltd. Wet-laid nonwoven E glass fiber surface mat 60 is typically white. The core material 10 is an EPS core material. The high-temperature resistant food preservation film 30 is typically a food preservation film used for microwave heating. The 3K carbon fiber upper shell 71 and the 3K carbon fiber lower shell 72 are both formed from 3K prepreg fabric, and after forming, they are CNC cut into predetermined shapes.

[0053] The second step is pre-molding. First, the core material 10 is inserted into the vacuum bag 20. Then, breathable cotton is installed in the vacuum bag 20. The breathable cotton is close to the core material 10 and should not be piled up at the port of the vacuum bag 20 to avoid causing poor air extraction. Next, the two ends of the vacuum bag 20 are sealed by applying putty. Then, the vacuum bag 20 is tested for leakage. Then, the vacuum bag 20 is straightened on the core material 10. Next, the high-temperature resistant food preservation film 30 is wrapped around the vacuum bag 20 by pressing and wrapping it around once. Finally, several pieces of UD carbon fiber cloth 40 are stacked and wrapped around the high-temperature resistant food preservation film 30 to form several layers of UD carbon fiber cloth.

[0054] Specifically, before performing a leak test on the vacuum bag 20, the air inside the vacuum bag 20 needs to be removed to improve the accuracy of the leak test. This process typically takes 3 minutes to ensure there is no air inside the vacuum bag 20. After wrapping the high-temperature resistant cling film 30, air ducts are first fitted onto both ends of the core material 10 to prevent leaks at the ports. Then, masking tape is applied to the outside of the air ducts to prevent them from falling off. Finally, another layer of high-temperature resistant cling film 30 is wrapped around the masking tape to prevent it from sticking to the UD carbon fiber cloth 40. The air ducts are made of nylon and are mainly used to protect the vacuum bag 20 at the ports, preventing it from being ruptured under high pressure and causing leaks.

[0055] Also, when threading the core material 10 through the vacuum bag 20, ensure that the core material 10 passes smoothly through the vacuum bag 20. Do not use excessive force to thread the core material 10 to avoid damaging the vacuum bag 20 and causing air leakage. When arranging the vacuum bag 20 on the core material 10, ensure that the vacuum bag 20 is evenly distributed on the top and bottom of the core material 10. When the vacuum bag 20 is inside the entire core material 10, only leave 5-10mm to prevent the vacuum bag 20 from being too tight. Avoid leaving too much space, which may cause air pockets to accumulate. The high-temperature resistant food preservation film 30 should not be wrapped more than 2 times. Wrapping too much will cause the product to delaminate, which may cause the product to bulge. After wrapping, an inspection is required. The vacuum bag 20 should not be exposed. For any exposed areas of the vacuum bag 20, a small piece of high-temperature resistant food preservation film 30 should be applied separately. Do not wrap it a full circle again.

[0056] In this embodiment, based on the cross-sectional area of ​​the core material 10, a reasonable overlapping method is selected to facilitate overlapping and covering. (See reference...) Figure 9 At position A, when the cross-sectional area of ​​the core material 10 is small, one layer of UD carbon fiber cloth can be covered by a single piece of UD carbon fiber cloth 40. Correspondingly, the resin-impregnated glass fiber mat 50 is covered by a single piece. At the gripping position corresponding to the small cross-sectional area of ​​the core material 10, pads are provided to prevent the core material 10 from bending downwards, thus avoiding deformation of the core material 10 during the stacking process of the UD carbon fiber cloth 40. (See reference...) Figure 9 At position B, when the cross-sectional area of ​​the core material 10 is large, a layer of UD carbon fiber cloth is covered by two pieces of UD carbon fiber cloth 40, and the two ends of the two pieces of UD carbon fiber cloth 40 are spliced ​​together accordingly. Correspondingly, the resin-impregnated glass fiber mat 50 is covered by two pieces.

[0057] The third step is shaping. First, the resin-impregnated glass fiber mat 50 is stacked and wrapped around the UD carbon fiber cloth 40. Then, the glass fiber surface mat 60 is wrapped around the resin-impregnated glass fiber mat 50. Next, the 3K carbon fiber upper shell 71 and 3K carbon fiber lower shell 72 are spliced ​​together and wrapped around the glass fiber surface mat 60 to form a preform. Finally, the preform is placed in the pre-vacuum device 80 for pre-vacuuming to pre-press the preform.

[0058] Specifically, the pre-vacuum device 80 has a sealed air bag 81. After the preform is placed into the air bag 81, a pre-vacuum is performed, which can reduce the occurrence of subsequent bulging.

[0059] The fourth step is preheating. After attaching the nozzles to the ports of the preform, it is placed in the preheating fixture 90 to preheat the preform. Attaching the nozzles involves sealing the nozzles to the vacuum bag 20 to facilitate the connection of the positive pressure air source for PCM molding. In traditional technology, the preheating fixture 90 performs positive pressure blowing and negative pressure vacuuming during preheating, which has a significant impact on subsequent PCM molding. Positive pressure causes resin from the UD carbon fiber cloth 40 to overflow and remain on the surface of the preform, which cannot be completely cleaned. When placed in the PCM molding mold 100, this results in indentations and poor appearance. Some resin overflows onto the surface of the preform, solidifies, and severely affects the exhaust of gas from inside the preform, causing bulges. Vacuum not only fails to effectively remove gas from inside the preform but also draws flowing resin to the surface, leading to poor exhaust. Therefore, this preheating step only preheats the preform to reduce its impact on subsequent PCM molding.

[0060] Step 5, PCM molding: The preheated preform is placed into the PCM molding mold 100 for PCM molding. After PCM molding, the core material 10, vacuum bag 20, and high-temperature resistant plastic wrap 30 are removed to obtain carbon fiber hollow tube. The PCM molding mold 100 is equipped with a positive pressure air source and a negative pressure air source. The positive pressure air source is used to expand the vacuum bag 20 outward, and the negative pressure air source is used to draw the 3K carbon fiber upper shell 71 and 3K carbon fiber lower shell 72 outward.

[0061] Specifically, the PCM molding die 100 includes an upper die and a lower die, which together form a cavity 1001 for accommodating the carbon fiber hollow tube. The upper die and the lower die are sealed together so that the preheated preform is located in the sealed cavity. The blowing end of the positive pressure air source is connected to a nozzle, and the negative pressure air source is connected to the sealed cavity. The sealed connection between the upper die and the lower die can prevent air leakage from the sealed cavity where the preheated preform is located. The PCM molding die 100 is provided with a positive pressure air source interface 1003 and a negative pressure air source interface 1004 corresponding to the positive pressure air source and the negative pressure air source, respectively.

[0062] The negative pressure air source is equipped with an air source silencer 110 at the air intake end. The air source silencer can prevent the air intake end of the negative pressure air source from being blocked by resin. By blowing or replacing the air source silencer, it can be ensured that the air intake end of the negative pressure air source is not blocked. It is convenient to use. The air source silencer is usually detachably installed on an insert 120. The insert 120 is installed at the air intake end of the negative pressure air source. The setting of the insert 120 provides an installation position for the air source silencer 110.

[0063] In this embodiment, the lower mold is provided with a first sealing ring mounting groove on the outer periphery of the cavity of the PCM molding die 100. A first sealing ring 130 is provided in the first sealing ring mounting groove, so that the area enclosed by the first sealing ring 130 forms a sealed cavity when the upper and lower molds are closed. The air nozzle will be exposed outside the PCM molding die 100. Therefore, the first sealing ring and the air nozzle must fit tightly to avoid air leakage. The lower mold is also provided with an ejection mechanism 140. The ejection mechanism 140 includes an ejector rod 141 and an ejector block 142. The ejector block 142 is connected to the lower mold and the upper mold. The mold cavity 1001 is formed by the mold and the mold. The top of the lower mold is recessed downwards and a groove 1002 is provided. The ejector block is disposed in the groove. The top of the ejector rod is movably inserted through the bottom wall of the groove and abuts against the bottom of the ejector block. The top of the ejector rod 141 is provided with a sealing block 143. Correspondingly, the bottom of the ejector block is recessed upwards and a relief groove is provided. The outer periphery of the sealing block extends beyond the outer periphery of the ejector rod. A second sealing ring 150 is sandwiched between the bottom of the sealing block 143 and the bottom wall of the groove 1002 to seal the ejector mechanism 140 and further prevent air leakage.

[0064] In addition, four temperature measurement points are set on the upper and lower molds. The mold temperature must be measured before each product is put into the mold. This is because the probability of bulging is higher in the first mold during actual production. Since the upper and lower molds are closed during rest and the equipment is kept heated, the mold temperature is higher in the first mold. High temperature affects bulging. Therefore, the upper and lower molds need to be opened in advance for the first mold, and the product is put into the mold only after the mold temperature reaches the standard.

[0065] In production and application, the structure of this type of carbon fiber anti-bulging hollow tube can be used in carbon fiber automobile roll cages.

[0066] The key design focus of this invention is:

[0067] The main advantage is that by incorporating several vents into the UD carbon fiber cloth, its air-exhaust performance is improved. Both the resin-impregnated glass fiber mat and the glass fiber surface mat act as air guides, allowing internal gases to escape from the carbon fiber hollow tube through these guides. This prevents air from accumulating between the UD carbon fiber cloth and the 3K carbon fiber upper and lower shells, and ensures good bonding between the cloth and the 3K carbon fiber cloth without affecting the UD carbon fiber structure. The structural strength of the UD carbon fiber cloth and 3K carbon fiber cloth; and the high-temperature resistant food preservation film covering makes the surface of the UD carbon fiber cloth stacking smoother and flatter, which is convenient for the stacking of UD carbon fiber cloth. Moreover, the high-temperature resistant food preservation film is a release film, which is easy to remove; in addition, the positive pressure air source and the negative pressure air source together adhere the UD carbon fiber cloth and 3K carbon fiber cloth to the mold cavity wall of the PCM molding die, which makes the pre-formed body shaping effect better after preheating; reduce the bulging rate of carbon fiber hollow tubes and improve the yield of carbon fiber hollow tubes.

[0068] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for manufacturing a carbon fiber hollow tube, characterized in that, Includes the following steps: The first step is preparation, including the following materials: resin-impregnated glass fiber mat, glass fiber surface mat, 3K carbon fiber upper shell, 3K carbon fiber lower shell, core material, vacuum bag, high-temperature resistant food preservation film, and several pieces of UD carbon fiber cloth, wherein the UD carbon fiber cloth has several air vents; and the following equipment: a pre-vacuuming device, a preheating fixture, and a PCM molding die, wherein the preheating temperature of the preheating fixture is lower than the die temperature of the PCM molding die. The second step is pre-molding. First, the core material is inserted into the vacuum bag. Then, breathable cotton is placed in the vacuum bag, close to the core material. Next, the two ends of the vacuum bag are sealed by applying putty. Then, the vacuum bag is tested for air leakage. Then, the vacuum bag is straightened on the core material. Next, the high-temperature resistant plastic wrap is wrapped around the vacuum bag by pressing and wrapping it once. Finally, several pieces of UD carbon fiber cloth are stacked and wrapped around the high-temperature resistant plastic wrap to form several layers of UD carbon fiber cloth. The third step is shaping. First, the resin-impregnated glass fiber mat is layered and wrapped around the UD carbon fiber cloth. Then, the glass fiber surface mat is wrapped around the resin-impregnated glass fiber mat. Next, the 3K carbon fiber upper shell and 3K carbon fiber lower shell are spliced ​​together and wrapped around the glass fiber surface mat to form a preform. Finally, the preform is placed in a pre-vacuuming device for pre-vacuuming to initially press the preform together. The fourth step is preheating. After attaching the nozzles to the ends of the preform, place it into the preheating fixture to preheat the preform. The fifth step is PCM compression molding. The preheated preform is placed into a PCM compression molding mold for PCM compression molding. After PCM compression molding, the core material, vacuum bag, and high-temperature resistant plastic wrap are removed to obtain carbon fiber hollow tubing. The PCM compression molding mold is equipped with a positive pressure air source and a negative pressure air source. The positive pressure air source is used to expand the vacuum bag outward, and the negative pressure air source is used to draw the 3K carbon fiber upper shell and 3K carbon fiber lower shell outward.

2. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: In the preparation of materials, the UD carbon fiber cloth is punctured and perforated using a perforating roller to form the air pores, and the vacuum bag is humidified.

3. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: Before performing a leak test on the vacuum bag, the air inside the vacuum bag must be removed.

4. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: After wrapping the high-temperature resistant plastic wrap, firstly, air ducts are fitted on both ends of the core material to prevent air leakage at the ports. Then, masking tape is applied to the outside of the air ducts to prevent them from falling off. Finally, another layer of high-temperature resistant plastic wrap is wrapped on the surface of the masking tape to prevent the masking tape from sticking to the UD carbon fiber cloth.

5. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: When a layer of UD carbon fiber cloth is covered by one piece of UD carbon fiber cloth, the resin-impregnated glass fiber mat is one piece. When a layer of UD carbon fiber cloth is covered by two pieces of UD carbon fiber cloth, the two ends of the two pieces of UD carbon fiber cloth are spliced ​​together accordingly, and the resin-impregnated glass fiber mat is two pieces.

6. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: When stacking UD carbon fiber cloth, pads are placed at the corresponding gripping positions of the core material to prevent the core material from bending downwards.

7. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: The preheating temperature of the preheating fixture is 50-70 degrees Celsius, and the mold temperature of the PCM molding die is 130-150 degrees Celsius.

8. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: The PCM molding die includes an upper die and a lower die, which are sealed together so that the preheated preform is located in a sealed cavity. The blowing end of the positive pressure air source is connected to a nozzle, and the negative pressure air source is connected to the sealed cavity.

9. The method for manufacturing a carbon fiber hollow tube according to claim 8, characterized in that: The negative pressure air source is equipped with an air source silencer at the air intake end.

10. The method for manufacturing a carbon fiber hollow tube according to claim 1, characterized in that: The resin-impregnated glass fiber mat is an epoxy resin-impregnated glass fiber mat, and the glass fiber surface mat is a wet-laid nonwoven E glass fiber surface mat.

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