Molding process of carbon fiber product for vehicle

Abstract

The invention relates to the technical field of carbon fiber material forming, in particular to a forming process of a carbon fiber product for a vehicle. The forming process comprises the following steps: S1, laying a plurality of carbon fiber prepreg sheets on a horizontal platform; s2, heating and horizontally compacting all the laid carbon fiber prepreg sheets at a temperature capable of softening the carbon fiber prepreg sheets to form a carbon fiber prepreg blank; s3, the carbon fiber prepreg blank is put into a pre-forming mold to be subjected to cold press forming, and a pre-formed body is formed; and S4, the preformed metal outer plate, the adhesive film, the preformed body and the preformed metal inner plate are sequentially put into a forming mold with the temperature capable of curing the preformed body to be subjected to compression molding, so that the metal outer plate, the adhesive film, the preformed body and the metal inner plate are connected, and the carbon fiber product for the vehicle is formed. The invention aims to overcome the problem of poor quality of a carbon fiber product for a vehicle in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon fiber material molding, and in particular to a molding process of carbon fiber products for vehicles. Background Art

[0002] Carbon fiber products for vehicles are typically made using a molding process. This process involves placing a metal outer panel in a molding die, then laying the cut carbon fiber prepreg sheets layer by layer on the preformed metal outer panel according to preset positions; after the layers are laid, an adhesive film is laid on the carbon fiber prepreg sheets; then a preformed metal inner panel is placed on the adhesive film; and then the molding die heats and pressurizes the metal inner panel, adhesive film, carbon fiber prepreg sheets, and metal outer panel to solidify the carbon fiber prepreg sheets, thereby connecting the metal inner panel, carbon fiber prepreg sheets, and metal outer panel into a whole to form the carbon fiber product for vehicles.

[0003] During the layup process, on-site personnel need to lay the cut carbon fiber prepreg sheets one by one on the preformed metal outer panel. However, the surface of the metal outer panel is uneven (for example, the metal outer panel has a certain curvature), which makes the laid carbon fiber prepreg sheets uneven as well. This leads to poor bonding between the carbon fiber prepreg sheets, for example, gaps between two carbon fiber prepreg sheets, thus reducing the quality of the cured carbon fiber product for vehicles. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem of poor quality of carbon fiber products for vehicles in the prior art.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a carbon fiber product forming process for vehicles, which comprises the following steps: S1, laying a plurality of carbon fiber prepreg sheets on a horizontal platform in a preset order and at a preset angle; S2, heating all the carbon fiber prepreg sheets after the laying is completed at a temperature that can soften the carbon fiber prepreg sheets, and at the same time, horizontally compacting all the carbon fiber prepreg sheets after the laying is completed to form a carbon fiber prepreg blank; S3, placing the carbon fiber prepreg blank into a preforming mold for cold pressing to form the carbon fiber prepreg blank into a preform that can match the forming mold; S4, sequentially placing a preformed metal outer panel, an adhesive film, a preform and a preformed metal inner panel into a forming mold at a temperature that can solidify the preform for compression molding, so that the metal outer panel, the adhesive film, the preform and the metal inner panel are connected to form a carbon fiber product for vehicles.

[0006] In some embodiments, the carbon fiber prepreg sheet comprises a resin component that enables the preform to be quickly cured and shaped.

[0007] In some embodiments, step S1 further includes: performing vacuum treatment after the first layer of carbon fiber prepreg sheet is laid; starting from laying the second layer, vacuum treatment is performed on the laid carbon fiber prepreg sheet after each preset number of layers are laid.

[0008] In some embodiments, before step S1 , the method further includes: cutting the carbon fiber prepreg raw material to obtain a plurality of carbon fiber prepreg sheets having a preset shape.

[0009] In some embodiments, in step S2 , all the carbon fiber prepreg sheets after the layup are heated and pressurized simultaneously by a press.

[0010] In some embodiments, the molding time in the preforming mold is a first preset time, and the molding time in the molding mold is a second preset time, and the second preset time is greater than the first preset time.

[0011] In some embodiments, the first preset duration ranges from 20 seconds to 40 seconds, and the second preset duration ranges from 4 minutes to 6 minutes.

[0012] In some embodiments, step S5 further includes: within a third preset time period, the forming mold applies a first pressure to the metal outer plate, the adhesive film, the preform and the metal inner plate; within a fourth preset time period, the forming mold applies a second pressure to the metal outer plate, the adhesive film, the preform and the metal inner plate; wherein the fourth preset time period is longer than the third preset time period, and the second pressure is greater than the first pressure.

[0013] In some embodiments, step S5 further includes: installing the carbon fiber product for a vehicle on a cooling and shaping tool for cooling.

[0014] In some embodiments, step S5 further includes trimming and polishing the carbon fiber product for a vehicle after cooling.

[0015] The above technical solution of the present invention has the following beneficial effects:

[0016] The carbon fiber prepreg sheets are laid out on a horizontal platform so that each layer of the carbon fiber prepreg sheets can be laid out on a relatively flat surface, avoiding poor bonding effects caused by an uneven operating surface during laying. Moreover, the carbon fiber prepreg sheets are compacted horizontally after laying, and the connection between the carbon fiber prepreg sheets is more stable and tight, so the carbon fiber prepreg blanks have better quality. Better quality carbon fiber prepreg blanks help to form better quality preforms, thereby improving the quality of carbon fiber products for vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 11 is a flow chart of a carbon fiber product forming process for a vehicle according to one embodiment of the present invention. DETAILED DESCRIPTION

[0018] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention.

[0019] like Figure 1 As shown, the present invention provides a process for forming a carbon fiber product for a vehicle.

[0020] Example 1

[0021] The carbon fiber product forming process for vehicles includes the following steps: S1, laying multiple carbon fiber prepreg sheets on a horizontal platform according to a preset order and preset angle; S2, heating all the carbon fiber prepreg sheets after the laying is completed at a temperature that can soften the carbon fiber prepreg sheets, and at the same time horizontally compacting all the carbon fiber prepreg sheets after the laying is completed to form a carbon fiber prepreg blank; S3, placing the carbon fiber prepreg blank into a preforming mold for cold pressing to form the carbon fiber prepreg blank into a preform that can match the forming mold; S4, sequentially placing the preformed metal outer plate, adhesive film, preform and preformed metal inner plate into a forming mold at a temperature that can solidify the preform for compression molding, so that the metal outer plate, adhesive film, preform and metal inner plate are connected to form a carbon fiber product for vehicles.

[0022] Specifically, in step S1, the carbon fiber prepreg sheets are laid on a horizontal platform so that each layer of the carbon fiber prepreg sheets can be laid on a relatively flat surface, avoiding poor lamination due to an uneven operating surface during laying, such as avoiding gaps between carbon fiber prepreg sheets that are bonded to each other, or avoiding wrinkles in the carbon fiber prepreg sheets. At the same time, compared to laying on a forming mold, laying on a horizontal platform is easier to operate, helps to simplify the laying process and shorten the laying time, thereby improving the implementation efficiency of the laying.

[0023] Specifically, in step S2, after the laid carbon fiber prepreg sheet is heated, the carbon fiber prepreg sheet will soften. The viscosity and deformation ability of the softened carbon fiber prepreg sheet will increase, which can improve the bonding effect between the carbon fiber prepreg sheets and thus improve the quality of the carbon fiber prepreg blank. After the carbon fiber prepreg sheets are horizontally compacted, the connection between the carbon fiber prepreg sheets is tighter, which helps to improve the quality of the carbon fiber prepreg blank. Moreover, during the horizontal compaction of the carbon fiber prepreg sheets, the pressure helps to discharge the air between the softened carbon fiber prepreg sheets, which helps to improve the quality of the carbon fiber prepreg blank. It should be noted that the softening temperature of the carbon fiber prepreg sheet is lower than the curing molding temperature, so the flexibility of the softened carbon fiber prepreg sheet increases at this time, which is more conducive to horizontal compaction. It should also be noted that the carbon fiber prepreg sheet itself has a certain flexibility at room temperature. The softening of the carbon fiber prepreg sheet refers to the carbon fiber prepreg sheet becoming softer and stickier than the carbon fiber prepreg sheet at room temperature after being heated.

[0024] Specifically, in step S3, when the carbon fiber prepreg blank is placed in the preforming mold, although the carbon fiber prepreg blank is separated from the heat source, the temperature of the carbon fiber prepreg blank is still higher than room temperature. At this time, the carbon fiber prepreg blank is relatively soft, so the carbon fiber prepreg blank is easy to be shaped and the material is not easily damaged.

[0025] Specifically, in step S4, the temperature of the forming mold is heated in advance to a temperature that can solidify the preform, which helps to shorten the solidification time. After the preformed metal outer plate, adhesive film, preform and preformed metal inner plate are placed in sequence, the forming mold heats and pressurizes the above materials, and the preform is gradually solidified and formed during the temperature increase, and the metal outer plate, adhesive film, preform and preformed metal are connected together to form a carbon fiber product for a vehicle. In this carbon fiber product, a carbon fiber prepreg is sandwiched between the metal outer plate and the metal inner plate, which helps to reduce weight and increase strength. In addition, the adhesive film is a common material in the field for bonding carbon fiber prepregs and metal plates, and the present invention will not go into details.

[0026] In this embodiment, the carbon fiber prepreg sheets are laid on a horizontal platform so that each layer of the carbon fiber prepreg sheets can be laid on a relatively flat surface, avoiding poor bonding effect caused by uneven operating plane during laying; and the carbon fiber prepreg sheets are horizontally compacted after laying, and the connection between the carbon fiber prepreg sheets is more stable and tight, so the carbon fiber prepreg blank has better quality. Better quality carbon fiber prepreg blanks help to form better quality preforms, thereby improving the quality of carbon fiber products for vehicles.

[0027] Example 2

[0028] This embodiment includes all the contents of the embodiment 1. In addition, in this embodiment, the carbon fiber prepreg sheet contains a resin component that can rapidly solidify and shape the preform.

[0029] Specifically, the resin is a fast-curing molding resin, which helps accelerate the curing and molding speed of carbon fiber prepreg sheets, carbon fiber prepreg blanks, and preforms, thereby shortening the molding time of carbon fiber products for vehicles and improving production efficiency. It should be noted that the fast-curing molding resin can be made of materials commonly used in the field. For example, the present invention can use the medium-temperature curing prepreg resin for rapid molding disclosed in Publication No. CN107868401A or the medium-temperature fast-curing epoxy resin disclosed in Publication No. CN104558526A.

[0030] In some embodiments, in the carbon fiber prepreg sheet, the mass percentage range of the above-mentioned resin (i.e., the above-mentioned rapid curing molding resin) is 32%-40%. Those skilled in the art will understand that the carbon fiber prepreg sheet comprises carbon fiber and resin, and the resin can bond the carbon fiber into a whole, thereby giving full play to the mechanical properties of the carbon fiber. If the mass percentage of the resin is lower than 32%, the carbon fibers will not be fully impregnated with the resin, resulting in some carbon fibers not being bonded together, thereby reducing the mechanical properties of the entire carbon fiber prepreg sheet. If the mass percentage of the resin is higher than 40%, the content of carbon fiber is low at this time, and the mechanical properties of the entire carbon fiber prepreg sheet will also be poor. Therefore, controlling the mass percentage range of the resin to 32%-40% helps to give full play to the mechanical properties of the carbon fiber, thereby maintaining good mechanical properties of the carbon fiber prepreg sheet.

[0031] Example 3:

[0032] This embodiment includes all the contents of Embodiment 1 and Embodiment 2. In this embodiment, step S1 further includes: performing a vacuum treatment after the first layer of carbon fiber prepreg sheets is laid; and starting from the second layer, vacuuming the already laid carbon fiber prepreg sheets after each predetermined number of layers are laid.

[0033] Specifically, after the first layer of carbon fiber prepreg sheets is laid, the already laid carbon fiber prepreg sheets, along with the horizontal platform, are vacuum-bagged and sealed. The vacuum bag is then evacuated to allow air to escape between the carbon fiber prepreg sheets. After evacuation is complete, the vacuum bag is removed. Then, starting with the second layer, after each predetermined number of layers are laid, the already laid carbon fiber prepreg sheets, along with the horizontal platform, are vacuum-bagged again and sealed. The vacuum bag is then evacuated to allow air to escape between the carbon fiber prepreg sheets. For example, vacuuming is performed once after every two, three, or four layers are laid. Similarly, after each vacuuming is completed, the vacuum bag is removed. After the carbon fiber prepreg sheets are laid, a final vacuuming treatment is performed. Through multiple vacuuming treatments, the carbon fiber prepreg sheets adhere well to each other, helping to improve the quality of the carbon fiber prepreg blank. Of course, vacuuming can also be performed using dedicated vacuuming equipment for carbon fiber prepregs, which is not limited by the present invention.

[0034] Furthermore, in this embodiment, before step S1, the following step may be performed: cutting the carbon fiber prepreg raw material to obtain a plurality of carbon fiber prepreg sheets having a predetermined shape. Specifically, the carbon fiber prepreg raw material can be cut using a cutting device. The cutting device is a common device in the art, and the present invention will not further describe its structure and principle.

[0035] Example 4:

[0036] This embodiment includes all the contents of embodiment 1 and embodiment 2. In addition, in step S2, all the carbon fiber prepreg sheets after the plying is completed are heated and pressurized simultaneously by a press.

[0037] Specifically, the press is preheated to a temperature that can soften the carbon fiber prepreg sheets, and then the carbon fiber prepreg sheets that have been laid are placed on the horizontal workbench of the press for horizontal compaction. The press heats and presses all the carbon fiber prepreg sheets so that all the carbon fiber prepreg sheets are formed into carbon fiber prepreg blanks. The press is a common device in this field, and the present invention will not go into details about its structure and principle. Of course, other equipment can also be used to heat and pressurize the carbon fiber prepreg sheets, and the present invention does not limit this.

[0038] Example 5

[0039] This embodiment includes all the contents of the second embodiment. In this embodiment, the molding time in the preforming mold is a first preset time, and the molding time in the molding mold is a second preset time, and the second preset time is longer than the first preset time.

[0040] Specifically, when the carbon fiber prepreg blank is placed in the preforming mold, although the carbon fiber prepreg blank is separated from the heat source, the carbon fiber prepreg blank is still higher than room temperature, so the carbon fiber prepreg blank still has a certain flexibility. The molding method of the preforming mold is cold pressing, that is, the temperature of the preforming mold is room temperature. During the preforming process of the carbon fiber prepreg blank, the temperature of the carbon fiber prepreg blank will drop. The preforming time of the carbon fiber prepreg blank is less than the time of molding and curing, that is, the preforming time of the carbon fiber prepreg blank is shortened, so the preform is still higher than room temperature when it is taken out of the preforming mold, so the preform will maintain a certain flexibility. When the preform is placed on the metal outer plate, the flexible preform is more likely to fit between the metal outer plate.

[0041] Furthermore, in this embodiment, the first preset time can range from 20 seconds to 40 seconds, shortening the preforming time of the carbon fiber prepreg blank. Therefore, the preform is still above room temperature when it is removed from the preforming mold, and the preform maintains a certain degree of flexibility. The second preset time can range from 4 minutes to 6 minutes, which provides sufficient curing time for the preform to ensure a good connection between the metal outer plate, the film, the preform, and the metal inner plate. Of course, this embodiment preferably uses the above-mentioned carbon fiber prepreg sheet containing a fast-curing resin so that the preform can be completed within the first preset time, and the carbon fiber product for the vehicle can also be completed within the second preset time.

[0042] Example 6

[0043] This embodiment includes all the contents of Embodiments 1 and 2. Furthermore, in this embodiment, step S5 may further include: applying a first pressure to the metal outer plate, the adhesive film, the preform, and the metal inner plate during a third preset duration; and applying a second pressure to the metal outer plate, the adhesive film, the preform, and the metal inner plate during a fourth preset duration; wherein the fourth preset duration is longer than the third preset duration, and the second pressure is greater than the first pressure.

[0044] Specifically, the temperature of the forming mold reaches the curing molding temperature of the carbon fiber prepreg sheet, and the preform will first be heated to the softening temperature in the forming mold, and then continue to be heated to the curing molding temperature. When the preform is at a softening temperature, a smaller first pressure is applied in a shorter period of time, and the film and preform can be stably compacted, and it helps to discharge the air between the metal outer plate, the film, the preform and the metal inner plate. After the film and preform are stably compacted, a larger second pressure is applied for a longer period of time, so that the metal outer plate, the film, the preform and the metal inner plate are connected more tightly and the preform is gradually solidified. Finally, the metal outer plate, the film, the preform and the metal inner plate are connected to form a carbon fiber product for a vehicle.

[0045] Example 7

[0046] This embodiment includes all the contents of embodiment 1 and embodiment 2. In this embodiment, step S5 may further include: installing the carbon fiber product for a vehicle on a cooling and shaping tool for cooling.

[0047] Specifically, automotive carbon fiber products are prone to deformation during cooling. The automotive carbon fiber products are mounted on a cooling and shaping fixture, where various parts of the automotive carbon fiber products are restrained to prevent excessive dimensional changes. Of course, the cooling and shaping fixture is common equipment in the art, and the present invention will not elaborate on its structure and materials.

[0048] Furthermore, in this embodiment, step S5 may further include: trimming and polishing the carbon fiber product for a vehicle after cooling.

[0049] Specifically, the tolerance of the carbon fiber product for vehicles after cooling is relatively large, and trimming and polishing are required to ensure that the carbon fiber product for vehicles can match the installation position of the vehicle.

[0050] In some embodiments, the carbon fiber product for a vehicle may be a vehicle B-pillar or a vehicle front hood, etc., which is not limited in the present invention.

[0051] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above are only preferred implementation methods of the present invention. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of the present invention, they can make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the present invention to other occasions without improvement, should be regarded as the scope of protection of the present invention.

Claims

1. A carbon fiber product molding process for a vehicle, characterized in that: The steps include: S1. Laying a plurality of carbon fiber prepreg sheets on a horizontal platform in a preset order and at a preset angle; S2, heating all the carbon fiber prepreg sheets after the plying is completed at a temperature that can soften the carbon fiber prepreg sheets, and at the same time horizontally compacting all the carbon fiber prepreg sheets after the plying is completed to form a carbon fiber prepreg blank; S3, placing the carbon fiber prepreg blank into a preforming mold for cold pressing, so that the carbon fiber prepreg blank forms a preform that can match the forming mold; S4. Sequentially placing the preformed metal outer panel, the adhesive film, the preformed body and the preformed metal inner panel into the molding die at a temperature that can solidify the preformed body for compression molding, so that the metal outer panel, the adhesive film, the preformed body and the metal inner panel are connected to form a carbon fiber product for a vehicle.

2. The process for forming a carbon fiber product for a vehicle according to claim 1, characterized in that: The carbon fiber prepreg sheet contains a resin component that can rapidly solidify and shape the preform.

3. The process for forming a carbon fiber product for a vehicle according to claim 1 or 2, characterized in that: The step S1 further comprises: After the first layer of carbon fiber prepreg sheets is laid, vacuum treatment is performed; Starting from laying the second layer, after laying a preset number of layers each time, the laid carbon fiber prepreg sheets are vacuumed.

4. The process for forming a carbon fiber product for a vehicle according to claim 3, characterized in that: Before step S1, the following steps are also included: The carbon fiber prepreg raw material is cut and cut to obtain a plurality of carbon fiber prepreg sheets with preset shapes.

5. The process for forming a carbon fiber product for a vehicle according to claim 1 or 2, characterized in that: In the step S2, all the carbon fiber prepreg sheets after the layering are heated and pressurized at the same time by a press.

6. The process for forming a carbon fiber product for a vehicle according to claim 2, characterized in that: The molding time in the preforming mold is a first preset time, and the molding time in the molding mold is a second preset time, and the second preset time is greater than the first preset time.

7. The process for forming a carbon fiber product for a vehicle according to claim 6, characterized in that: The first preset time length ranges from 20 seconds to 40 seconds, and the second preset time length ranges from 4 minutes to 6 minutes.

8. The process for forming a carbon fiber product for a vehicle according to claim 1 or 2, characterized in that: The step S5 further comprises: During a third preset time period, the forming die applies a first pressure to the metal outer plate, the adhesive film, the preform, and the metal inner plate; During a fourth preset time period, the forming die applies a second pressure to the metal outer plate, the adhesive film, the preform, and the metal inner plate; The fourth preset time duration is longer than the third preset time duration, and the second pressure is greater than the first pressure.

9. The process for forming a carbon fiber product for a vehicle according to claim 1 or 2, characterized in that: The step S5 further comprises: The carbon fiber product for a vehicle is installed on a cooling and shaping tool for cooling.

10. The process for forming a carbon fiber product for a vehicle according to claim 9, characterized in that: The step S5 further comprises: The carbon fiber product for a vehicle after cooling is trimmed and polished.

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