Carbon fiber structural member and molding process method thereof

Abstract

The application discloses a carbon fiber structural member and a forming process method thereof. The method comprises the following steps: laying a carbon fiber prepreg in a hot-pressing mold to obtain a large surface part through hot-pressing forming, wherein the large surface part comprises a large surface part feature structure and a sink structure; and placing the large surface part in an injection mold to inject a structure part at the sink structure to obtain the carbon fiber structural member. The thermoplastic resin is formed into the large surface part and the structure part through co-curing, so that the integrity, consistency, stability and interface bonding strength of the carbon fiber structural member are improved, the continuity of the fibers in the thermoplastic composite material in the large surface part is ensured, the carbon fiber structural member has good rigidity and strength, the process flow is simplified, the forming cycle is shortened, the production efficiency is improved and the cost is reduced without processing the glue-pulling structure. In the case of ensuring the pulling force and the bonding force, the thickness is not restricted, and the thin-walled structural member forming can be realized. The thermoplastic material is used to form the large surface part, the production environment pollution is reduced, the finished product is easy to shape, and the finished product can be recycled.

Description

Technical Field

[0001] This application relates to the field of terminal equipment technology, and in particular to a carbon fiber structural component and its molding process. Background Technology

[0002] Carbon fiber composites are characterized by low specific gravity, high specific modulus, high specific strength, and fatigue resistance. As structural components, they are widely used in laptops, tablets, smartphones, smart wearable devices, portable smart information terminals, and other fields.

[0003] Carbon fiber structural components made from carbon fiber composites are commonly formed by first hot-pressing the large-area structure and then injection molding the structural part. The structural part is then physically riveted to the large-area structure via a glue-stretching mechanism, with the glue-stretching mechanism holes penetrating the large-area sheet through milling, punching, or laser machining. However, this forming method disrupts the continuity of the fibers within the carbon fiber composite material, leading to a decrease in the finished product's stiffness, flexural strength, and impact resistance. Summary of the Invention

[0004] This application provides a carbon fiber structural component and its molding process to solve the problem that commonly used molding methods easily damage the continuity of the internal fibers of the structural component, resulting in a reduction in stiffness and strength.

[0005] In a first aspect, this application provides a molding process method for carbon fiber structural components, comprising: providing carbon fiber prepreg; laying the carbon fiber prepreg in a hot press mold and hot pressing it to obtain a large surface area, the large surface area including a large surface feature structure and a recessed structure; placing the large surface area in an injection mold and injection molding the structural part at the recessed structure to obtain a carbon fiber structural component.

[0006] The carbon fiber structural component molding process provided in this application involves stacking carbon fiber prepreg in a hot press mold, followed by hot pressing to obtain a large-area section, which includes a large-area feature structure and a recessed structure. The large-area section is then placed in an injection mold, and the recessed structure is injection molded to form a structural part, resulting in a co-cured, integrally molded carbon fiber structural component. Co-curing the large-area section and structural part with thermoplastic resin improves the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component, ensuring the continuity of the internal fibers of the thermoplastic composite material in the large-area section, thus giving the carbon fiber structural component good stiffness and strength. Furthermore, it eliminates the need for a pull-out structure, simplifying the process, shortening the molding cycle, improving production efficiency, and reducing costs. While ensuring pull-out force and bonding force, there are no thickness limitations, enabling the molding of thin-walled structural components. Integral molding of the carbon fiber structural component reduces the number of component parts, facilitating assembly and improving reliability. Using thermoplastic materials to mold the large-area section instead of traditional thermosetting materials reduces environmental pollution during production, makes the finished product easy to shape, and allows for the recycling of thermoplastic composite materials.

[0007] In some implementations, carbon fiber prepreg is formed by impregnating carbon fibers with thermoplastic resin. Thus, using carbon fiber thermoplastic composites to manufacture carbon fiber structural components results in less environmental pollution during production, shape repositioning, recyclability, and a green, low-carbon footprint.

[0008] In some implementations, the hot press mold includes a first hot press mold and a second hot press mold; and, laying carbon fiber prepreg in the hot press mold and hot pressing to form a large surface area includes: laying carbon fiber prepreg in the first hot press mold and hot pressing to form a carbon fiber sheet; wherein the surface of the first hot press mold is flat and the surface of the carbon fiber sheet is flat; placing the carbon fiber sheet in the second hot press mold and hot pressing to form a large surface area feature structure and a recessed structure to obtain a large surface area.

[0009] In some implementations, the hot pressing temperature of the first hot pressing is higher than the melting temperature of the thermoplastic resin; the hot pressing temperature of the second hot pressing is higher than the softening temperature of the thermoplastic resin.

[0010] In some implementations, carbon fiber prepreg is laid in a hot press mold, including: using a lamination method to lay multiple layers of carbon fiber prepreg in the hot press mold. This ensures that the large surface area formed later has a certain thickness.

[0011] In some implementations, the carbon fibers in the same layer of carbon fiber prepreg are arranged in one of the following ways: unidirectional arrangement, two-dimensional fabric, three-dimensional fabric, or multi-axial fabric. Two-dimensional fabrics include plain weave, twill weave, or satin weave, while three-dimensional fabrics include orthogonal structures, interlocking structures, or multi-layer interconnected structures. By using different arrangement methods for the carbon fibers, the strength and impact resistance of the large sections formed later are ensured.

[0012] In some implementations, the prepreg is stacked in at least one of parallel stacking, orthogonal stacking, or staggered stacking. This allows for the stacking of multiple layers of carbon fiber prepreg using different methods, ensuring that the subsequently formed large sections have a certain thickness while increasing strength.

[0013] In some implementations, the carbon fiber in the carbon fiber prepreg is always the first fiber; or, the carbon fiber prepreg uses multiple mixed fiber prepregs, where the fiber types include both the first and second fibers. Multiple layers of carbon fiber prepregs form a composite laminate, where all layers are made of carbon fiber prepreg, or a mixed laminate is formed using carbon fiber prepreg and multiple mixed fiber prepregs. The first fiber includes one of viscose-based carbon fiber, PAN-based carbon fiber, or pitch-based carbon fiber; the second fiber includes one of glass fiber, ceramic fiber, alumina fiber, basalt fiber, aramid fiber, PBO fiber, polyaryl ester fiber, graphite fiber, or carbon nanotube fiber. This allows for the use of different types of fibers to fabricate carbon fiber structural components, thereby improving their strength and damage tolerance.

[0014] In some implementations, the recessed structure is formed by the surface of the large facet recessing inwards; the carbon fibers in the large facet are continuous and have a regular arrangement and orientation; the fibers adjacent to the recessed structure are spaced apart from the recessed structure. In this way, the recessed structure is formed only within the structure of the thermoplastic resin, without destroying the continuity and orientation of the carbon fibers, and without sacrificing structural strength and stiffness.

[0015] In some implementations, the large facial features include at least one of stepped surfaces, curved surfaces, rounded corners, and angular corners; the surface of the recessed structure includes at least one of planar, serrated, grid-like, columnar, and prismatic protrusions; and the structural parts include at least one of snap-fit, stud, and groove. This allows carbon fiber structural components to have different structural features to suit different application scenarios.

[0016] In some implementations, before injection molding the structural components at the recessed platform, the surface of the recessed platform structure is treated using methods such as cleaning, laser engraving, and plasma treatment. This increases the surface roughness and cleanliness of the recessed platform structure, thereby improving the injection molding bond strength between the injection molding material and the recessed platform structure.

[0017] In some implementations, before injection molding the structural part at the recessed platform, the process includes: preheating the recessed platform structure of the large surface area using directional heating; or preheating the entire large surface area using overall heating; wherein the preheating temperature is higher than the softening temperature of the thermoplastic resin. Preheating the large surface area softens it, allowing for better bonding between the resin material of the large surface area and the resin material of the injection molding material during injection molding, achieving co-curing and integral molding of the structural part and the large surface area.

[0018] In some implementations, the injection molding material matrix is ​​made of thermoplastic resin; the thermoplastic resin system of the injection molding material matrix is ​​the same as that of the carbon fiber prepreg. In this way, the matrix material of the structural part and the matrix material of the large part are the same, and they form a common phase after melting together, ensuring interfacial bonding and improving the injection molding bond strength between the large part and the structural part.

[0019] Secondly, this application provides a molding process method for carbon fiber structural components, including: providing carbon fiber prepreg; laying the carbon fiber prepreg in a first hot press mold, and obtaining a carbon fiber sheet through a first hot press molding; wherein the surface of the first hot press mold is flat, and the surface of the carbon fiber sheet is flat; placing the carbon fiber sheet in a hot press injection molding integral mold, and integrally molding the large-face structural features and injection molding structural parts to obtain a carbon fiber structural component.

[0020] The carbon fiber structural component molding process provided in this application involves stacking carbon fiber prepreg in a first hot-press mold, obtaining a carbon fiber sheet after the first hot-press molding; and then performing a second hot-press molding and injection molding on the carbon fiber sheet using a hot-press injection molding mold to obtain a co-cured, integrally molded carbon fiber structural component including the large-area section and the structural section. By co-curing the large-area section and structural section with thermoplastic resin, the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component can be improved, ensuring the continuity of the internal fibers of the thermoplastic composite material in the large-area section, giving the carbon fiber structural component good stiffness and strength. Furthermore, it eliminates the need for processing the adhesive-stretched structure, simplifying the process flow, shortening the molding cycle, improving production efficiency, and reducing costs; while ensuring pull-out force and bonding force, there are no thickness limitations, enabling the molding of thin-walled structural components. Integral molding of the carbon fiber structural component reduces the number of component parts, facilitating assembly and improving reliability. Using thermoplastic materials to mold the large-area section instead of traditional thermosetting materials can reduce environmental pollution during production, the finished product is easy to shape, and the thermoplastic composite material is recyclable.

[0021] In some implementations, carbon fiber sheets are placed in a thermoforming injection mold to form large facial structural features and injection-molded structural parts, including: placing the carbon fiber sheet in the thermoforming injection mold, performing a second thermoforming of the carbon fiber sheet using the thermoforming injection mold to form the large facial structural features; and using the thermoforming injection mold to melt the injection material and inject it into the injection position of the carbon fiber sheet to form the structural parts.

[0022] In some implementations, carbon fiber prepreg is formed by impregnating carbon fibers with thermoplastic resin; the hot pressing temperature of the first hot pressing is higher than the melting temperature of the thermoplastic resin; the hot pressing temperature of the second hot pressing is higher than the softening temperature of the thermoplastic resin.

[0023] Thirdly, this application provides a carbon fiber structural component, characterized in that it is manufactured using the molding process method for carbon fiber structural components as provided in the first aspect. The carbon fiber structural component includes a large surface area and a structural portion. The surface of the large surface area includes a large surface feature structure and a recessed structure. The interior of the large surface area includes multiple layers of carbon fibers, which are continuous and have a regular arrangement and orientation. The carbon fibers include first fibers and / or second fibers. The structural portion is injection molded into the recessed structure, and the bottom of the structural portion is spaced from the first or second fiber of the adjacent layer in the large surface area.

[0024] The carbon fiber structural component provided in this application embodiment features a co-cured integral molding of the structural part and the large-area part, eliminating the need for adhesive-stretching structures, simplifying the process, improving production efficiency, and reducing costs. Eliminating adhesive-stretching structures removes thickness limitations, enabling the molding of thin-walled structural components. Integral molding reduces the number of component parts, facilitating assembly and improving reliability. Co-curing the large-area part and structural part enhances the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component, ensuring the continuity of carbon fibers within the composite material, resulting in excellent stiffness and strength. Furthermore, using thermoplastic materials as the skeleton instead of traditional thermosetting materials reduces environmental pollution during production, and the product is easy to shape and recyclable. Attached Figure Description

[0025] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a structural diagram of a structural component;

[0027] Figure 2 This is a structural diagram of another type of structural component;

[0028] Figure 3 This is a schematic diagram of the carbon fiber structural component provided in the embodiments of this application;

[0029] Figure 4 This is the first method flowchart of the molding process for carbon fiber structural parts provided in the embodiments of this application;

[0030] Figure 5 This is a schematic diagram of the structure of the carbon fiber prepreg provided in the embodiments of this application;

[0031] Figure 6 This is a schematic diagram of the arrangement of the multilayer carbon fiber prepreg provided in the embodiments of this application;

[0032] Figure 7This is the first molding route diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application;

[0033] Figure 8 This is the first process flow diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application;

[0034] Figure 9 This is the second molding route diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application;

[0035] Figure 10 This is the second process flow diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application;

[0036] Figure 11 This is a second method flowchart of the molding process for carbon fiber structural parts provided in the embodiments of this application;

[0037] Figure 12 This is the third molding route diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application;

[0038] Figure 13 This is the third process flow diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application;

[0039] Figure 14 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application;

[0040] Figure 15 This is a schematic diagram of the rotating shaft mechanism provided in the embodiments of this application;

[0041] Figure 16 This is a schematic diagram of the door panel provided in the embodiment of this application.

[0042] Illustration:

[0043] 10-Large surface structure, 11-First carbon fiber, 12-Stretching structure hole, 20-Feature structure, 21-Second carbon fiber, 30-Bonded part;

[0044] 100-Large face, 101-Large face feature structure, 102-Sunken structure, 103-Carbon fiber, 104-Thermoplastic resin, 100a-Carbon fiber prepreg, 100a-1-First layer of carbon fiber prepreg, 100a-2-Second layer of carbon fiber prepreg, 100b-Carbon fiber sheet.

[0045] 200 - Structural part, 201 - Short fiber, 202 - Resin matrix;

[0046] 301-First fuselage, 302-Second fuselage, 303-Display screen, 304-Rotating mechanism, 3041-Rotating base, 3042-Door panel, 3043-Connector, 3044-Rotating part. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the protection scope of this application.

[0048] In the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0049] Furthermore, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0050] The following explanations of the technical terms mentioned in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0051] Carbon fiber, an inorganic high-performance fiber with a carbon content exceeding 90%, is transformed from organic fibers through a series of heat treatments. It is a new material with excellent mechanical properties. Carbon fiber composites are characterized by low specific gravity, high specific modulus, high specific strength, and fatigue resistance. As structural components, they are widely used in laptops, tablets, smartphones, smart wearable devices, portable smart information terminals, and other fields. Carbon fiber composites mainly include carbon fiber reinforced thermosetting resin composites and carbon fiber reinforced thermoplastic resin composites.

[0052] Figure 1 This is a structural schematic diagram of a structural component.

[0053] like Figure 1 As shown, the structural component includes a large surface structural part 10 and a feature structural part 20, with the feature structural part 20 located on the large surface structural part 10. The large surface structural part 10 is the structural base, and the feature structural part 20 consists of structures such as bosses, threaded pillars, and undercuts on the structural base.

[0054] The large surface structure 10 includes a first carbon fiber 11, which is a continuous fiber; the feature structure 20 includes a second carbon fiber 21, which is a short fiber.

[0055] Structural components made of carbon fiber composite materials are commonly formed using thermoforming. Thermoforming refers to a method of molding and curing prepreg into a finished product under heat and pressure. However, thermoforming relies on a mold as a template and can only construct planar structures or relatively simple geometric shapes; it cannot integrally form complex structures such as bosses, threaded pillars, or undercuts. The forming process for structural components involves first thermoforming the large-area structural part 10, and then injection molding the feature structural part 20. One implementation method is to physically rivet the feature structural part 20 to the large-area structural part 10 using a glue-stretching structure.

[0056] However, this forming method requires milling, punching, laser processing, and computer-controlled machining (CNC) to create adhesive-stretching structural holes 12 in the large-area structural section 10, which penetrate the upper and lower surfaces of the large-area structural section 10. This disrupts the continuity of the first carbon fiber 11 within the carbon fiber composite material, reducing the mechanical properties of the composite material, specifically leading to a decrease in the finished product's stiffness, flexural strength, and impact resistance. Furthermore, the adhesive-stretching structural holes 12 require CNC machining, resulting in numerous processes and low efficiency in this forming method.

[0057] The large-area structural section 10 is made of thermosetting continuous fiber composite material, while the characteristic structural section 20 is made of thermoplastic short fiber composite material. The use of different matrix materials for the large-area structural section 10 and the characteristic structural section 20 results in two separate phases and a phase separation interface, leading to weak bonding between them. Furthermore, the large-area structural section 10 and the characteristic structural section 20 are separate structures, making them highly susceptible to breakage. Using thermosetting materials would result in severe chemical pollution in the production environment, and the materials are not reshapeable or recyclable.

[0058] With the development of products that are thin, lightweight, and highly reliable, carbon fiber composite materials are required to not only have higher strength and stiffness, but also thinner thickness. The thin-walled structure poses a severe challenge to design and molding. However, the hole 12 in the stretchable structure limits the lower limit of the thin-walled structure design, with a minimum thickness of 0.3mm, which prevents the structural components from being made thinner and lighter, i.e., the thickness of the structural components cannot be reduced.

[0059] To facilitate the explanation of the position of each component in the structure, an exemplary embodiment of this application establishes a three-dimensional coordinate system based on the structure, wherein the x-axis direction is the width direction of the structure, the y-axis direction is the length direction of the structure, and the z-axis direction is the thickness direction of the structure.

[0060] Figure 2 This is a structural diagram of another type of structural component.

[0061] like Figure 2 As shown, in another implementation, the large surface structure 10 is connected to the feature structure 20 via the adhesive bonding portion 30. Specifically, the large surface structure 10 is first hot-pressed, the injection molding area is surface-treated by dispensing adhesive, and then the feature structure 20 is injection molded.

[0062] However, although this molding method does not destroy the fiber continuity of the large surface structure 10, the bonding strength of the feature structure 20 is low, and it is easy to detach from the large surface structure 10, reducing the reliability of the structural component.

[0063] To address the aforementioned technical problems, this application provides a carbon fiber structural component and its molding process. By co-curing and molding the large surfaces and structural parts, the integrity, stability, and interfacial bonding strength of the carbon fiber structural component are improved, ensuring the continuity of the fibers within the composite material and giving the carbon fiber structural component good stiffness and strength. Furthermore, thin-walled structural components can be molded without the need for adhesive bonding.

[0064] Figure 3 This is a schematic diagram of the carbon fiber structural component provided in the embodiments of this application.

[0065] like Figure 3 As shown in the embodiment of this application, the carbon fiber structural component includes: a large surface area 100 and a structural portion 200.

[0066] The large face 100 is the structural matrix of the carbon fiber structural component. The surface of the large face 100 includes the large face feature structure 101 and the recessed structure 102. The interior of the large face 100 includes multiple layers of carbon fiber 103. The carbon fiber 103 is continuous and has a regular arrangement and orientation, for example, a straight orientation.

[0067] The structural part 200 is embedded in the recessed structure 102, and the structural part 200 and the large surface area 100 are co-cured and integrally formed, which can improve the stiffness and strength of the carbon fiber structural component. The bottom of the structural part 200 is spaced from the adjacent layer of carbon fiber 103 in the large surface area 100. In this way, the structural part 200 will not damage the structure of the carbon fiber 103 in the large surface area 100, so that the carbon fiber 103 maintains its continuous straight line characteristics, thereby making the structural component strong without sacrificing stiffness.

[0068] The large surface area 100 is made of thermoplastic continuous fiber composite material, while the structural part 200 is made of thermoplastic short fiber composite material. In this way, the large surface area 100 and the structural part 200 use the same matrix material, and after they melt together, they form a common phase, ensuring good interfacial bonding. Furthermore, using thermoplastic materials results in less environmental pollution during production, allows for shape reshaping, recyclability, and is green and low-carbon.

[0069] The carbon fiber structural component provided in this application embodiment features a structural section 200 and a large section 100 that are co-cured and integrally formed, eliminating the need for adhesive bonding, simplifying the process, improving production efficiency, and reducing costs. The elimination of adhesive bonding removes thickness limitations, enabling the molding of thin-walled structural components (thickness ≤ 0.3 mm). Integral molding reduces the number of component parts, facilitating assembly and improving reliability. Co-curing the large section 100 and structural section 200 enhances the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component, ensuring the continuity of the carbon fiber 103 within the composite material, resulting in excellent stiffness and strength. Furthermore, using a thermoplastic material as the skeleton instead of traditional thermosetting materials reduces environmental pollution during production, makes the product easy to shape, and allows for recycling.

[0070] Figure 4 This is the first method flowchart of the molding process for carbon fiber structural parts provided in the embodiments of this application.

[0071] like Figure 4 As shown, in some embodiments, the molding process of carbon fiber structural components includes the following steps S101-S103:

[0072] Step S101: Provide carbon fiber prepreg.

[0073] The carbon fiber prepreg 100a is formed by impregnating carbon fiber 103 with thermoplastic resin 104 and then encapsulating the carbon fiber 103 with thermoplastic resin 104.

[0074] In the structure of the single-layer carbon fiber prepreg 100a, the arrangement of the carbon fibers 103 includes one of the following: unidirectional arrangement, two-dimensional fabric, three-dimensional fabric, or multi-axial fabric, so that the arrangement of the carbon fibers 103 is regular. Among them, the two-dimensional fabric includes plain weave fabric, twill weave fabric, or satin weave fabric, etc., and the three-dimensional fabric includes orthogonal structure, corner interlocking structure fabric, or multi-layer connection structure, etc.

[0075] Figure 5 This is a schematic diagram of the structure of the carbon fiber prepreg provided in an embodiment of this application. Wherein, Figure 5 Image (a) shows a side view of carbon fiber prepreg. Figure 5 (a) shows a top view of carbon fiber prepreg.

[0076] like Figure 5As shown in (a) and (b), the single-layer carbon fiber prepreg 100a comprises a layer of carbon fiber 103 coated with thermoplastic resin 104. The single-layer carbon fiber 103 comprises multiple carbon fibers 103 arranged in a unidirectional manner. This can be understood as the multiple carbon fibers 103 being parallel to each other.

[0077] Thermoplastic resin 104 serves as the matrix for the carbon fiber structural component, and carbon fiber 103 is distributed within the thermoplastic resin. The carbon fiber 103 is continuous, regularly arranged, and oriented in a straight line.

[0078] Thermoplastic resin 104 may include polyethylene terephthalate (PET), polyamide fiber (PA), polyphthalamide (PPA), polycarbonate (PC), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polysulfone (PSU), polyethersulfone (PES), polyetheretherketone (PEEK), polyetherketoneketone (PAEK), polyetherketoneketone (PEKK), thermoplastic polyurethanes (TPU), polypropylene (PP), polyethylene (PE), etc.

[0079] In carbon fiber prepreg, carbon fiber 103 can be the first fiber. The first fiber includes viscose-based carbon fiber, polyacrylonitrile (PAN)-based carbon fiber, pitch-based carbon fiber, etc. PAN-based carbon fiber is preferred. The proportion of carbon fiber in the finished structural parts is between 30% and 70%.

[0080] Alternatively, the carbon fiber prepreg can be made from a variety of blended fiber prepregs, where the fiber types include a first fiber and a second fiber. The second fiber can be one of the following: glass fiber, ceramic fiber, alumina fiber, basalt fiber, aramid fiber, poly-p-phenylene benzobisoxazole (PBO) fiber, polyarylate fiber, graphite fiber, or carbon nanotube fiber.

[0081] Step S102: The carbon fiber prepreg is laid in a hot press mold and hot-pressed to form a large face, which includes a large face feature structure and a recessed platform structure.

[0082] The hot press mold (not shown in the figure) has different structural features on its surface. These different structural features are used to form different large facial feature structures 101 and recessed structures 102.

[0083] The carbon fiber prepreg 100a is cut to fit the shape of the hot press mold.

[0084] In some embodiments, the carbon fiber prepreg 100a can be multilayered, and multiple layers of carbon fiber prepreg 100a are laid in a hot press mold in a stacking manner to ensure that the large surface area 100 formed subsequently has a certain thickness. For example, the carbon fiber prepreg 100a can be 5 layers.

[0085] The stacking method includes at least one of parallel stacking, orthogonal stacking, or staggered stacking. Parallel stacking means that the layers of carbon fiber prepreg 100a are parallel to each other. Orthogonal stacking means that two adjacent layers of carbon fiber prepreg 100a are stacked orthogonally in a 0° / 90° direction. Staggered stacking means that the angle formed between the layers of carbon fiber prepreg 100a is between 0° and 180°.

[0086] To optimize the flatness of the finished carbon fiber structural components, it is preferable to arrange the layers of carbon fiber prepreg 100a in an orthogonal stacking manner.

[0087] Figure 6 This is a schematic diagram showing the arrangement of the multilayer carbon fiber prepreg provided in an embodiment of this application. Wherein, Figure 6 (a) is a side view. Figure 6 (b) and (c) are top views.

[0088] like Figure 6 As shown in (a), taking a two-layer carbon fiber prepreg 100a as an example, the first layer of carbon fiber prepreg 100a-1 includes n carbon fibers 103, and the second layer of carbon fiber prepreg 100a-2 includes n carbon fibers 103.

[0089] When using a parallel stacking method, the first layer of carbon fiber prepreg 100a-1 and the second layer of carbon fiber prepreg 100a-2 are parallel, and the extension directions of the carbon fibers 103 in the two layers are parallel.

[0090] like Figure 6As shown in (b), when using an orthogonal stacking method, the first layer of carbon fiber prepreg 100a-1 is arranged along the 0° direction, and the second layer of carbon fiber prepreg 100a-2 is arranged along the 90° direction. That is, the first layer of carbon fiber prepreg 100a-1 and the second layer of carbon fiber prepreg 100a-2 are perpendicular to each other, and the extension directions of the carbon fibers 103 in the two layers are perpendicular to each other.

[0091] like Figure 6 As shown in (c), when using an interleaved stacking method, the first layer of carbon fiber prepreg 100a-1 is arranged along the 0° direction, and the second layer of carbon fiber prepreg 100a-2 is arranged along the 45° direction. The angle formed between the first layer of carbon fiber prepreg 100a-1 and the second layer of carbon fiber prepreg 100a-2 is 45°.

[0092] It should be noted that in this embodiment, only the extension direction of the carbon fiber 103 in the single-layer carbon fiber prepreg 100a is taken as the 0° direction. The 0° direction can be defined according to actual application conditions and is not limited here. Also, to clearly show the angles between the layers of carbon fiber prepreg 100a, Figure 6 The carbon fiber prepreg 100a shown in (b) and (c) has a relatively small width, but in practical applications, the carbon fiber prepreg 100a can have a wider width. That is to say, Figure 6 The dimensions of the carbon fiber prepreg 100a shown in the various schematic diagrams are only for illustrating the stacking relationship and are not intended to limit the actual dimensions.

[0093] In some embodiments, the multilayer carbon fiber prepreg 100a forms a composite material stack, wherein all composite material stacks are made of carbon fiber prepreg, or a mixed stack is formed of carbon fiber prepreg and a variety of mixed fiber prepregs.

[0094] In one implementation, the carbon fibers in the composite material stack are all of the first fiber type. That is, the carbon fibers in each layer of carbon fiber prepreg 100a are of the same type and all use the first fiber to form a multilayer first fiber prepreg stack.

[0095] In another implementation, the carbon fibers in the composite laminate are of the type of first fiber and multiple mixed fibers, wherein the multiple mixed fibers include the first fiber and the second fiber. That is, the multilayer carbon fiber prepreg 100a can be used as a mixed laminate of a first fiber prepreg and a mixed fiber prepreg formed by the first fiber and the second fiber.

[0096] Figure 7 This is the first molding route diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application; Figure 8 This is the first process flow diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application.

[0097] like Figure 7 and Figure 8 As shown in (a), the multilayer carbon fiber prepreg 100a is prepared according to... Figure 6 The carbon fiber prepreg 100a of appropriate size is laid in a hot press mold after being stacked in any of the shown stacking methods and then cut. The carbon fiber prepreg 100a is then hot-pressed in the hot press mold to obtain a large face 100 including a large face feature structure 101 and a recessed structure 102. There are multiple large face feature structures 101 and multiple recessed structures 102.

[0098] The hot pressing temperature of the hot pressing molding is higher than the melting temperature of the thermoplastic resin 104 to ensure good welding of each layer of carbon fiber prepreg 100a, thereby ensuring the reliability of the large surface area 100.

[0099] The large facial feature structure 101 refers to the features possessed by the surface of the large facial face 100. The large facial feature structure 101 includes at least one of a step, a curved surface, a rounded corner (R-angle), and a chamfer (C-angle). Among them, a rounded corner (R-angle) refers to an inner or outer rounded corner on a part. A chamfer (C-angle) is a bevel, such as a 45-degree chamfer.

[0100] The recessed structure 102 is located at the injection position of the large surface area 100, which is the location where the structural part 200 will be injection molded from the large surface area 100. The recessed structure 102 is formed by indentation from the surface of the large surface area 100, and can be considered as a groove, the surface of which is the surface of the recessed structure 102. The surface of the recessed structure 102 includes at least one of the following: planar, serrated, mesh-like, columnar, and prismatic protrusions. Different recessed structures 102 are used for subsequent injection molding of different structural parts 200. The recessed structure 102 has complex surface features, which can increase the bonding area with the injection molding material, thereby improving the bonding strength of the injection molded part.

[0101] The carbon fibers 103 in the large surface area 100 are continuous and the orientation of the carbon fibers 103 is linear. The carbon fibers 103 adjacent to the recessed structure 102 are spaced L0 apart from the recessed structure 102. That is to say, the recessed structure 102 is only formed within the structure of the thermoplastic resin 104, without destroying the continuity and orientation of the carbon fibers 103, and without losing structural strength and stiffness.

[0102] In this way, the carbon fiber 103 in the large section 100 remains continuous, ensuring the reliability and stability of the large section 100, which in turn results in good structural strength and stiffness of the carbon fiber structural components subsequently manufactured.

[0103] Step S103: Place the large face part in the injection mold, and inject the structural part at the sinking structure to obtain the carbon fiber structural part.

[0104] The structural part 200 includes at least one of the following: a snap fastener, a stud, a groove, etc.

[0105] The mold provided by the injection mold has the same shape as the structural part 200 to be formed, so as to form the corresponding structural part 200.

[0106] like Figure 7 and Figure 8 As shown in (b), after the large part 100 is cut, it is placed in an injection mold (not shown in the figure), and the structural part 200 is injected into each of the recessed structures 102 of the large part 100 using the injection mold.

[0107] The structural part 200 is injection molded using a thermoplastic short fiber composite material, which is formed by impregnating short fibers with a thermoplastic resin. The structural part 200 includes short fibers 201 and a resin matrix 202, with the resin matrix 202 encapsulating a large number of short fibers 201. The resin matrix 202 is a thermoplastic resin. In other words, the injection molding material matrix required for injection molding is a thermoplastic resin; and the thermoplastic resin system of the injection molding material matrix is ​​the same as the thermoplastic resin system of the carbon fiber prepreg 100a.

[0108] In this way, the injection molding material of the structural part 200 is the same thermoplastic resin system used in the large part 100. The two have the same matrix material and form a common phase after melting with each other, which ensures the interfacial bonding effect and improves the injection molding bonding strength between the large part 100 and the structural part 200.

[0109] After injection molding, there is a gap L0 between the bottom of the structural part 200 and the carbon fiber 103 of the adjacent layer. That is to say, the structural part 200 is only embedded in part of the structure of the thermoplastic resin 104, without destroying the continuity and orientation of the carbon fiber 103, and without losing structural strength and stiffness. The carbon fiber 103 of the adjacent layer may be the first fiber or the second fiber.

[0110] In this way, the carbon fiber 103 in the large section 100 remains continuous, ensuring the reliability and stability of the large section 100, thereby making the carbon fiber structural component have good structural strength and stiffness.

[0111] In some embodiments, before injection molding the structural portion at the recessed platform structure 102, the surface of the recessed platform structure 102 may be surface treated by means of cleaning, laser engraving and plasma treatment.

[0112] Before injection molding, each injection point is cleaned, laser-engraved, and treated with plasma to increase the surface roughness and cleanliness of the sinking structure 102, thereby improving the injection bonding strength between the injection molding material and the sinking structure 102.

[0113] In some embodiments, before injection molding the structural part at the sinkhole structure 102, the process may further include: preheating the large part 100 and maintaining the temperature for a certain period of time; after preheating, transferring it to the injection mold.

[0114] In one implementation, directional heating is used to preheat the recessed platform structure 102 of the large face 100. In another implementation, overall heating of the large face 100 is used to preheat the entire large face 100.

[0115] The preheating method can be one of laser, infrared, or ultrasonic methods. The preheating temperature is higher than the glass transition temperature of the resin material, and preferably higher than the softening temperature of the thermoplastic resin.

[0116] Preheating the large part 100 softens it, allowing the resin material of the large part 100 to better bond with the resin material of the injection molding material during injection molding, thus achieving co-curing and integral molding of the structural part 200 and the large part 100.

[0117] After injection molding is completed and cooled, the injection molded part is removed and then surface-treated to obtain a one-piece carbon fiber structural component. The surface treatment includes deburring.

[0118] The following describes the molding process method for the first carbon fiber structural component provided in this application, using two specific implementation methods.

[0119] First specific implementation method:

[0120] PA6 is used as the thermoplastic resin matrix, and T700 unidirectional carbon fiber prepreg 100a is used. The thickness of the single-layer carbon fiber prepreg 100a is between 0.1mm and 0.2mm, and the resin content is 35%-45%. The injection molding material is PA short glass fiber reinforced injection molding compound.

[0121] Preheat the hot press mold to 200℃; proceed as follows: Figure 6 As shown in (c), the cut carbon fiber prepreg 100a is stacked in five layers at 0°, 45°, 0°, -45°, and 0° (the long side direction is defined as the 0° direction), and laid in a hot press mold. The hot press mold is closed and placed in a hot press machine. The pressure is increased to 60kg-80kg, the hot press machine temperature is set to 240℃-270℃, and the hot press is performed for 720s-1200s. After cooling to 80℃, the hot press part is removed and laser-cut to obtain a single hot press part with a large facial feature structure 101 and a recessed structure 102, namely the large facial feature 100.

[0122] After preheating the injection mold to 180℃-220℃, place the hot press part (large part 100) into the mold and maintain the temperature for 120s-300s to preheat the large part 100. Then, inject PA short glass fiber reinforced injection molding material into each sink structure 102. The injection temperature of the injection material is 260℃-280℃ to form the structural part 200. After cooling to 80℃, remove the injection molded part, remove the burrs, and obtain the one-piece carbon fiber structural part.

[0123] The carbon fiber structural component obtained in the first specific embodiment is taken as Example 1, and Comparative Example 1 is defined as follows: Figure 1 The structural component shown is made according to a commonly used pull-fit riveting structure. The mechanical properties of the carbon fiber structural component provided in this application embodiment are tested by comparing the pull-out force data and stiffness data of Example 1 and Comparative Example 1.

[0124] The performance of carbon fiber structural components includes the pull-out force and stiffness of structural part 200. The pull-out force of structural part 200 refers to the force value when structural part 200 breaks with large part 100, which is used to describe the bonding strength between structural part 200 and large part 100. Stiffness refers to the ability of the carbon fiber structural component as a whole to resist elastic deformation or breakage when subjected to maximum force.

[0125] When testing the pull-out force of structural part 200, taking three injection molding positions as an example, that is, the number of structural parts 200 of the carbon fiber structural component is 3, and the number of feature structural parts 20 of the structural component is 3. The injection molding positions correspond to the structural parts 200 and the feature structural parts 20, and these three injection molding positions are used as the test points for the pull-out force of structural part 200. Table 1 shows the pull-out force data of the structural parts of Example 1 and Comparative Example 1.

[0126] When testing stiffness, taking six measurement points as an example, the six measurement points are distributed at different positions of the carbon fiber structure in Example 1, which corresponds to different positions of the structure in Comparative Example 1. Table 2 shows the stiffness test data of Example 1 and Comparative Example 1.

[0127] Table 1 Pull-out force data of structural components

[0128]

[0129] Table 2 Stiffness Test Data

[0130]

[0131] Based on Tables 1 and 2, comparing the mechanical properties of Example 1 and Comparative Example 1, the pull-out force of the structural part 200 at each injection position in Example 1 is approximately 26 N, which is greater than the pull-out force at the corresponding injection position in Comparative Example 1; the measured stiffness of Example 1 at different measurement positions is 14.4-35.3 N / mm, which is greater than the stiffness of Comparative Example 1 at the corresponding measurement position (4.1-18.8 N / mm).

[0132] As can be seen, since the through holes of the adhesive-bonded structure are eliminated in the structure of the carbon fiber structural component provided in this application embodiment, the mechanical properties of the carbon fiber structural component are better than those of Comparative Example 1. Therefore, the mechanical properties of the carbon fiber structural component provided in this application embodiment are better.

[0133] The second specific implementation method:

[0134] PC is used as the thermoplastic resin matrix, and M40J unidirectional carbon fiber prepreg 100a is used. The thickness of a single layer of carbon fiber prepreg 100a is between 0.12mm and 0.2mm, and the resin content is 40%-50%. The injection molding material is PC short carbon fiber reinforced injection molding compound.

[0135] Preheat the hot press mold to 200℃; proceed as follows: Figure 6 As shown in (b), the pre-cut carbon fiber prepreg 100a is stacked in three layers at 0° and 90° orthogonal angles and laid in a hot press mold. The hot press mold is closed and placed in a hot press machine. The pressure is increased to 60kg-80kg, the temperature of the hot press machine is set to 260℃-280℃, and the hot press is held for 720s-1200s. After cold pressing at room temperature for 300s-600s, the hot press part is taken out and laser-cut to obtain a single hot press part with a large facial feature structure 101 and a recessed structure 102, namely the large facial feature 100.

[0136] Preheat the injection mold, setting the mold temperature to 100℃, 110℃, 125℃, and 135℃ respectively (Examples 2, 3, 4, and 5). Place the hot-pressing part (large part 100) into the mold and hold it at a constant temperature for 120s-300s to preheat the large part 100. Then, inject PC short carbon fiber reinforced injection molding material into each recessed structure 102 at an injection temperature of 270℃-300℃ to form the structural part 200. After cooling for 30s-120s, remove the injection molded part, remove burrs, and obtain an integrally formed carbon fiber structural part. The mold temperature of the injection mold is the temperature at which the large part 100 is preheated and softened.

[0137] The carbon fiber structural parts obtained by the large surface area 100 in the second specific embodiment at different softening temperatures are used as Examples 2, 3, 4, and 5. By comparing the tensile fracture force data and lateral thrust fracture force data of Examples 2-5, the mechanical properties of the carbon fiber structural parts formed at which softening temperature are good are tested.

[0138] The tensile fracture force refers to the maximum force that causes the structural portion 200 to break when pulled along its extension direction, resulting in the structural portion 200 breaking from the large portion 100. The lateral fracture force refers to the maximum force that causes the structural portion 200 to break from the large portion 100 when pushed from one side along its extension direction. For example, the extension direction of the structural portion 200 is the z-axis direction, and the extension direction of the large portion 100 is the x-axis direction.

[0139] When testing the pull-out force of structural part 200, taking six injection points as an example, namely injection point A, injection point B, injection point C, injection point D, injection point E, and injection point F. Table 3 shows the pull-out fracture force data of structural part 200 of carbon fiber structural component at different mold temperatures (softening temperatures), and Table 4 shows the lateral thrust fracture force data of structural part 200 of carbon fiber structural component at different mold temperatures (softening temperatures).

[0140] Table 3. Pull-out fracture force data of the structural part at different mold temperatures.

[0141]

[0142]

[0143] Table 4. Lateral thrust fracture force data of the structural part at different mold temperatures.

[0144]

[0145] Based on Tables 3 and 4, comparing Examples 2-5, as the softening temperature increases, the tensile breaking force and lateral breaking force of the structural part 200 gradually increase, indicating that the bonding force between the structural part 200 and the large part 100 is better. However, the softening temperature should not be too high. If the softening temperature is close to the melting temperature of the thermoplastic resin 104, the thermoplastic resin 104 is prone to melting at high temperatures, which can easily cause the carbon fiber 103 to bend, affecting the structural strength and stiffness.

[0146] Therefore, when the injection molding temperature corresponding to Example 2 is higher than 110°C, the structural part 200 and the large part 100 are well bonded, and both the pull-out force and the lateral thrust are significantly improved, resulting in good overall integrity after co-curing. In other words, a softening temperature above 110°C can produce carbon fiber structural parts with good mechanical properties.

[0147] The carbon fiber structural component molding process provided in this application involves stacking carbon fiber prepreg 100a in a hot press mold, and then hot-pressing it to obtain a large surface area 100. The large surface area 100 includes a large surface feature structure 101 and a recessed structure 102. The large surface area 100 is placed in an injection mold, and a structural portion 200 is injection molded at the recessed structure 102 of the large surface area 100 to obtain a co-cured integrally molded carbon fiber structural component. By co-curing the large surface area 100 and the structural portion 200 with thermoplastic resin, the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component can be improved, ensuring the continuity of the internal fibers of the thermoplastic composite material in the large surface area, giving the carbon fiber structural component good stiffness and strength. Furthermore, it eliminates the need for processing the pull-out structure, simplifying the process flow, shortening the molding cycle, improving production efficiency, and reducing costs. While ensuring pull-out force and bonding force, there are no thickness limitations, enabling the molding of thin-walled structural components. The integral molding of the carbon fiber structural component reduces the number of component parts, facilitating assembly and improving reliability. Using thermoplastic materials to mold large facial features (100mm) instead of traditional thermosetting materials can reduce environmental pollution during production, make finished products easy to shape, and make thermoplastic composite materials recyclable.

[0148] In some embodiments, this application provides a second molding process method for carbon fiber structural components. The difference between this method and the first molding process method for carbon fiber structural components lies in the content of step S102. The rest of the content can be referred to the content of the first molding process method for carbon fiber structural components, and will not be repeated here.

[0149] In this scenario, the hot pressing mold can include a first hot pressing mold and a second hot pressing mold. The surface of the first hot pressing mold is flat, meaning that the surface of the first hot pressing mold has no structural features or no complex structural features, which facilitates automated mechanical laying, continuous hot pressing, and rapid mass production. The surface of the second hot pressing mold has different structural features, which are used to form different large facial feature structures 101 and recessed structures 102.

[0150] In some embodiments, step S102 can guarantee the following steps S201-S202:

[0151] Step S201: The carbon fiber prepreg is laid in the first hot press mold and formed by the first hot press to obtain carbon fiber sheet.

[0152] In step S202, the carbon fiber sheet is placed in the second hot press mold and subjected to a second hot press molding to form the large facial feature structure and the sinking structure, thus obtaining the large facial face.

[0153] Figure 9 This is the second molding route diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application; Figure 10 This is the second process flow diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application.

[0154] like Figure 9 and Figure 10 As shown in (a), in step S201, the multilayer carbon fiber prepreg 100a is prepared according to... Figure 6 The carbon fiber prepreg 100a of appropriate size is stacked in any of the shown stacking methods, then cut and laid in the first hot press mold. The carbon fiber prepreg 100a is hot-pressed and formed using the first hot press mold, and then removed after cooling to obtain carbon fiber sheet 100b.

[0155] The surface of carbon fiber sheet 100b is planar and lacks any special structural features, exhibiting a plate-like structure. During the first hot-pressing process, the absence of surface features in the first hot-pressing mold results in a more uniform distribution of hot-pressing pressure. This better maintains the orientation of carbon fibers 103 in each layer of carbon fiber prepreg 100a, reducing surface quality and mechanical property degradation caused by fiber twisting, overlapping, and misalignment. Consequently, the resulting carbon fiber structural components exhibit better flatness and stiffness.

[0156] The hot pressing temperature of the first hot pressing is higher than the melting temperature of the thermoplastic resin 104, causing the thermoplastic resin 104 of each layer of carbon fiber prepreg 100a to melt, thereby ensuring good bonding of each layer of carbon fiber prepreg 100a and ensuring the reliability of the carbon fiber sheet 100b. For example, the melting temperature of the thermoplastic resin 104 is about 200°C, at which temperature the thermoplastic resin 104 can melt into a molten state.

[0157] The carbon fiber sheet 100b is processed by laser, CNC, punching and other methods to make the size of the carbon fiber sheet 100b meet the size requirements of the second hot pressing mold.

[0158] like Figure 9 and Figure 10 As shown in (b), in step S202, the carbon fiber sheet 100b that meets the size requirements is placed in the second hot press mold and subjected to a second hot press molding to form the large face feature structure 101 and the recessed structure 102, thereby obtaining the large face 100. The number of large face feature structures 101 and the number of recessed structures 102 are both multiple.

[0159] The second hot pressing is performed at a temperature higher than the softening temperature of the thermoplastic resin 104. This allows the carbon fiber sheet 100b to soften sufficiently for molding the large facial feature structure 101 and the recessed structure 102. For example, the softening temperature of the thermoplastic resin 104 is lower than its melting temperature, approximately 80°C. At this temperature, the thermoplastic resin 104 softens into a partially molten state, remaining non-flowing without disrupting the orientation of the carbon fiber 103, and is also easy to shape.

[0160] like Figure 9 and Figure 10 As shown in (c), the large surface area 100, obtained through two hot pressing processes, is placed in an injection mold, and the structural part 200 is injection molded at the recessed structure 102 to obtain a carbon fiber structural component. For details, please refer to the aforementioned step S103, which will not be repeated here.

[0161] It should be noted that before injection molding the structural part at the sinkhole structure 102, the molding process method of the carbon fiber structural part provided in this application embodiment may also include: the steps of treating the surface of the sinkhole structure 102 and preheating the large part 100. For details, please refer to the corresponding content of the foregoing embodiment, which will not be repeated here.

[0162] The following describes the molding process method for the second carbon fiber structural component provided in this application embodiment, using a specific implementation method as an example.

[0163] PA12 is used as the thermoplastic resin matrix, and T700 unidirectional carbon fiber prepreg 100a is used. The thickness of the single-layer carbon fiber prepreg 100a is between 0.05mm and 0.12mm, and the resin content is 40%-50%. The injection molding material is PA short carbon fiber reinforced injection molding compound.

[0164] According to such Figure 6 As shown in (b), the cut carbon fiber prepreg 100a is stacked in six layers at 0° and 90° orthogonal positions in a first hot press mold. The first hot press mold is closed and placed in a hot press machine. The machine temperature is set to 240℃-270℃, and the hot press pressure is gradually increased. The hot press is performed for 600s-900s, followed by a cold press at room temperature for 400s-600s before demolding to obtain a carbon fiber sheet 100b without surface feature structures.

[0165] After the carbon fiber sheet 100b is cut, it is placed into the second hot press mold. The mold temperature is set to 180℃-220℃ and the pressure is 150kg-180kg. After hot pressing for 60s-360s, it is held under pressure in the mold and cooled to 80℃ before demolding. After laser cutting, a hot press part with a large facial feature structure 101 and a recessed platform structure 102 is obtained, namely the large facial feature 100.

[0166] Preheat the injection mold to 160℃-200℃, and use a laser to heat the injection position for 10s-60s. Then, move the hot-pressed part (large part 100) into the injection mold to preheat the large part 100. Inject PA short carbon fiber reinforced injection molding material at 240℃-260℃ at each sinkhole structure 102 to form the structural part 200. After cooling to 80℃, remove the injection molded part, remove the burrs, and obtain the one-piece carbon fiber structural part.

[0167] The carbon fiber structural component obtained in this specific embodiment is taken as Example 6, and Comparative Example 2 is defined as follows: Figure 1 The structural component shown is made using a commonly used ply-riveting structure. The mechanical properties of the carbon fiber structural component provided in this application are tested by comparing the three-bar bend test data of Example 6 and Comparative Example 2.

[0168] The three-point bend test involves placing a specimen on two support points at a certain distance. A downward load is applied to the specimen at the midpoint between the two support points. When the three contact points of the specimen form two equal moments, a three-point bend occurs, and the specimen will break at the midpoint. The test measures the maximum force at which the specimen breaks.

[0169] When testing the fracture force value of the three-bar bend, taking four measurement positions as an example, namely measurement position L1, measurement position L2, measurement position R1, and measurement position R2. Table 5 shows the three-bar bend test data of Example 6 and Comparative Example 2.

[0170] Table 5 Test data for the three-pole bend

[0171] Test value Measurement bit L1 Measurement position L2 Measurement bit R1 Measurement position R2 Example 6 Fracture force (N) 27.0 26.2 25.8 26.5 Comparative Example 2 Fracture force (N) 18.0 24.5 17.6 21.8

[0172] Based on Table 5, the three-bar bending fracture force values ​​at each measurement point in Example 6 are 25.8N-27.0N, which is better than that in Comparative Example 2. Therefore, the carbon fiber structural component provided in this application has better mechanical properties.

[0173] The molding process of the carbon fiber structural component provided in this application involves stacking carbon fiber prepreg 100a in a first hot press mold, and obtaining a carbon fiber sheet 100b after a first hot press molding; then, a second hot press mold is used to perform a second hot press molding on the carbon fiber sheet 100b to obtain a large surface area 100, which includes a large surface feature structure 101 and a recessed structure 102; the large surface area 100 is placed in an injection mold, and a structural portion 200 is injection molded at the recessed structure 102 of the large surface area 100 to obtain a co-cured integrally molded carbon fiber structural component. By co-curing the large surface area 100 and the structural portion 200 with thermoplastic resin, the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component can be improved, ensuring the continuity of the internal fibers of the thermoplastic composite material in the large surface area, thus giving the carbon fiber structural component good stiffness and strength. Furthermore, the process eliminates the need for fabrication of the adhesive-bonded structure, simplifying the workflow, shortening the molding cycle, improving production efficiency, and reducing costs. While ensuring pull-out force and bonding strength, there are no thickness limitations, enabling the molding of thin-walled structural components. One-piece molding of carbon fiber structural components reduces the number of component parts, facilitating assembly and improving reliability. Molding large-area sections with thermoplastic materials instead of traditional thermosetting materials reduces environmental pollution during production, makes the finished product easy to shape, and allows for the recycling of thermoplastic composite materials.

[0174] Figure 11 This is the second method flowchart of the molding process for carbon fiber structural parts provided in the embodiments of this application.

[0175] like Figure 11 As shown, in some embodiments, the molding process of carbon fiber structural components includes the following steps S301-S303:

[0176] Step S301: Provide carbon fiber prepreg.

[0177] The content of step S301 can be referred to the content of step S101 provided in the aforementioned embodiment, and will not be repeated here.

[0178] In step S302, carbon fiber prepreg is laid in the first hot press mold and subjected to the first hot press molding to obtain carbon fiber sheet.

[0179] The surface of the first hot press mold is flat, and the surface of the carbon fiber sheet is flat; the hot pressing temperature of the first hot pressing is higher than the melting temperature of the thermoplastic resin.

[0180] Figure 12 This is the third molding route diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application; Figure 13 This is the third process flow diagram of the molding process method for carbon fiber structural parts provided in the embodiments of this application.

[0181] like Figure 12 and Figure 13 As shown in (a), the multilayer carbon fiber prepreg 100a is prepared according to... Figure 6 The carbon fiber prepreg 100a of appropriate size is stacked in any of the shown stacking methods, then cut and laid in the first hot press mold. The carbon fiber prepreg 100a is hot-pressed and formed using the first hot press mold, and then removed after cooling to obtain carbon fiber sheet 100b.

[0182] It should be noted that the content of step S302 can refer to the content of step S201 provided in the aforementioned embodiment, and will not be repeated here.

[0183] Step S303: Place the carbon fiber sheet into a hot-press injection molding mold to form the large facial structural features and injection-molded structural parts, thereby obtaining a carbon fiber structural component.

[0184] The thermoforming injection mold is a shared mold for both thermoforming and injection molding, featuring a large surface area 100 and structural parts 200. For example, the thermoforming injection mold includes a thermoforming module and an injection module. The thermoforming module has the structural features of the large surface area 100, and the injection module has the structural features of the structural parts 200. The thermoforming injection mold is used for integral molding of the large surface area 100 and the structural parts 200. The large surface area 100 includes a large surface feature structure 101.

[0185] like Figure 12 and Figure 13 As shown in (b), step S303 may include the following steps S3031-S3032:

[0186] Step S3031: Place the carbon fiber sheet in a hot-press injection molding mold, and use the hot-press injection molding mold to perform a second hot-press molding of the carbon fiber sheet to form a large facial feature structure.

[0187] In step S3032, the injection material is melted using a hot-press injection mold and then injected into the injection position of the carbon fiber sheet to form the structural part.

[0188] In step S3031, the carbon fiber sheet 100b is cut so that the size of the carbon fiber sheet 100b meets the size requirements of the hot-press injection molding integrated mold (not shown in the figure).

[0189] The cut carbon fiber sheet 100b is placed in a hot-press injection molding mold, and the carbon fiber sheet 100b is subjected to a second hot-press molding using the hot-press module of the hot-press injection molding mold. The hot-pressing temperature of the second hot-press molding is higher than the softening temperature of the thermoplastic resin 104.

[0190] The carbon fiber sheet 100b is first heated to above the softening temperature of the thermoplastic resin 104 using the hot pressing module of the hot pressing injection mold, so that the carbon fiber sheet 100b is fully softened; then pressure is applied to form the large facial feature structure 101.

[0191] In step S3032, the number of injection modules and the number of injection positions in the integrated hot-press injection mold are the same, with multiple injection modules corresponding one-to-one with multiple injection positions. Different injection modules have different structural features of the structural part 200, and each injection module also has an injection port. For example, the structural features of the structural part 200 include surface features and morphological features. The surface features include at least one of planar, serrated, mesh-like, columnar, and prismatic protrusions, and the morphological features include at least one of snap-fit, stud, and groove.

[0192] The injection module of the thermoforming injection mold melts the injection material and injects it through the injection port to mold the material into the injection position of the carbon fiber sheet 100b to form the structural part 200. After cooling, the part is demolded and surface treated to obtain the one-piece molded carbon fiber structural part.

[0193] In this way, the large surface area 100 and the structural part 200 are co-cured and molded in one step, which can reduce repeated heating / cooling processes, improve production efficiency, reduce energy consumption, and lower costs. Furthermore, one-step molding can also ensure the integrity of the finished product while maintaining the fiber orientation consistency of the large surface area 100, giving the finished product better rigidity and strength.

[0194] The following describes the molding process method for the third carbon fiber structural component provided in this application embodiment, using a specific implementation method as an example.

[0195] Using PPS as the thermoplastic resin matrix, two prepregs are employed: T800 unidirectional carbon fiber prepreg 100a and fiberglass cloth prepreg. The thickness of the single-layer carbon fiber prepreg 100a ranges from 0.06mm to 0.12mm, with a resin content of 35% to 45%. The fiberglass cloth prepreg also uses PPS as the resin matrix, with a thickness of 0.04mm to 0.10mm. The injection molding material is PPS short carbon fiber reinforced injection molding compound.

[0196] According to such Figure 6 In any of the stacking methods shown, the cut carbon fiber prepreg 100a and glass fiber prepreg are mixed and layered in a sequence of carbon fiber 0°, glass fiber, carbon fiber 0°, glass fiber, and carbon fiber 0°, and then laid in a first hot press mold. The first hot press mold is closed and placed in a hot press machine. The machine temperature is set to 300℃-330℃, and the hot pressing pressure is gradually increased to 60kg-80kg. The hot pressing is carried out for 300s-600s, and after holding the pressure and cold pressing to 100℃, the material is demolded to obtain a carbon fiber sheet 100b without surface feature structures.

[0197] After preheating the hot-press injection mold, place the cut carbon fiber sheet 100b into it, heat it to 280℃-300℃ for preheating, and then pressurize it to 80kg-100kg and hold it for 30s-120s. Inject PPS short carbon fiber reinforced injection molding material at 300℃-330℃ into each sink structure 102 to form the structural part 200. After cooling to 100℃, remove the injection molded part. After deburring and polishing, the one-piece carbon fiber structural part is obtained.

[0198] The carbon fiber structural component molding process provided in this application involves stacking carbon fiber prepreg 100a in a first hot press mold, and obtaining carbon fiber sheet 100b after a first hot press molding. A second hot press molding and injection molding are then performed on the carbon fiber sheet 100b using a hot press injection molding mold to obtain a co-cured, integrally molded carbon fiber structural component including a large surface area 100 and a structural portion 200. By co-curing the large surface area 100 and the structural portion 200 with thermoplastic resin, the integrity, consistency, stability, and interfacial bonding strength of the carbon fiber structural component can be improved, ensuring the continuity of the fibers within the thermoplastic composite material of the large surface area, thus giving the carbon fiber structural component good stiffness and strength. Furthermore, it eliminates the need for processing the adhesive-stretched structure, simplifying the process flow, shortening the molding cycle, improving production efficiency, and reducing costs. While ensuring pull-out force and bonding force, there are no thickness limitations, enabling the molding of thin-walled structural components. The integral molding of the carbon fiber structural component reduces the number of component parts, facilitating assembly and improving reliability. Using thermoplastic materials to mold large facial features (100mm) instead of traditional thermosetting materials can reduce environmental pollution during production, make finished products easy to shape, and make thermoplastic composite materials recyclable.

[0199] The carbon fiber structural components provided in this application can be applied to fields such as laptops, tablets, smartphones, smart wearable devices, and portable smart information terminals. The following description uses the application of carbon fiber structural components in the hinge mechanism of a foldable electronic device as an example.

[0200] Figure 14 This is a schematic diagram of the structure of the foldable electronic device provided in the embodiments of this application.

[0201] like Figure 14 As shown, the electronic device may include a first body 301, a second body 302, a display screen 303, and a rotating mechanism 304, wherein, Figure 14The dashed lines schematically indicate the area of ​​the pivot mechanism 304. The first body 301 and the second body 302 are respectively located on both sides of the axis of the pivot mechanism 304. The first body 301 and the second body 302 are respectively connected to the pivot mechanism 304, and can be rotated by the pivot mechanism 304 to reduce the angle between the first body 301 and the second body 302 until the foldable electronic device is in a folded state; or to increase the angle between the first body 301 and the second body 302 until the foldable electronic device is in an unfolded state.

[0202] The display screen 303 covers the first body 301, the second body 302, and the pivot mechanism 304, and is connected to the first body 301 and the second body 302 respectively. The rotation of the first body 301 and the second body 302 can cause the display screen 303 to bend or unfold. For example, the display screen 303 can be a flexible screen that can be bent, and the display screen 303 has a bending area, so that the display screen 303 can be bent in the bending area as the pivot mechanism 304 rotates.

[0203] To facilitate the explanation of the positions of various components in the foldable electronic device, this application embodiment establishes a three-dimensional coordinate system based on the foldable electronic device, wherein the x-axis direction is the width direction of the foldable electronic device, the y-axis direction is the length direction of the foldable electronic device, and the z-axis direction is the thickness direction of the foldable electronic device.

[0204] Figure 15 This is a schematic diagram of the rotating shaft mechanism provided in the embodiments of this application.

[0205] like Figure 15 As shown, the rotating shaft mechanism 304 includes a rotating shaft base 3041, two door panels 3042, two connecting parts 3043, and multiple sets of rotating parts 3044.

[0206] Two door panels 3042 are located on opposite sides of the pivot base 3041, and the display screen 303 covers the two door panels 3042, supporting the display screen 303. Two connectors 3043 are located on opposite sides of the pivot base 3041 and are connected to the first body 301 and the second body 302 respectively. For example, the door panels 3042 are movably connected to the connectors 3043 on the same side, and the rotating part 3044 is movably connected to the pivot base 3041. This movable connection can be either a rotating fit or a sliding connection.

[0207] Figure 16 This is a schematic diagram of the door panel provided in the embodiment of this application.

[0208] like Figure 16As shown, the door panel 3042 adopts the co-cured integrally molded carbon fiber structural component provided in the embodiment of this application. The door panel 3042 includes a large surface 100, and the surface of the large surface 100 facing the connector 3043 includes structural parts 200 such as buckles, studs, and grooves.

[0209] In this way, door panel 3042 adopts a co-cured, one-piece molded carbon fiber structural component. This one-piece structure not only improves the overall strength and structural stability of door panel 3042, but also reduces the number of parts, facilitating the assembly of the hinge mechanism and improving the assembly precision between door panel 3042 and other components. This also contributes to the lightweight design of the hinge mechanism. Furthermore, it improves the reliability and stability of foldable electronic devices while reducing cost and weight.

[0210] It should be noted that those skilled in the art, upon considering the specification and practicing the application disclosed herein, will readily conceive of other embodiments of this application. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope of this application is indicated by the following claims.

[0211] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A molding process for carbon fiber structural components, characterized in that, include: Provide carbon fiber prepreg; The carbon fiber prepreg is laid in a hot press mold and hot-pressed to form a large face, which includes a large face feature structure and a recessed structure. The large face is placed in an injection mold, and the structural part is injection molded at the sinkhole structure to obtain a carbon fiber structural component.

2. The molding process method for carbon fiber structural components according to claim 1, characterized in that, The carbon fiber prepreg is formed by impregnating carbon fibers with thermoplastic resin.

3. The molding process method for carbon fiber structural components according to claim 2, characterized in that, The hot pressing mold includes a first hot pressing mold and a second hot pressing mold; and, The process of laying the carbon fiber prepreg in a hot press mold and hot-pressing it to obtain a large surface area includes: The carbon fiber prepreg is laid in the first hot press mold and subjected to a first hot press molding process to obtain a carbon fiber sheet; wherein, the surface of the first hot press mold is flat and the surface of the carbon fiber sheet is flat. The carbon fiber sheet is placed in the second hot press mold and subjected to a second hot press molding process to form the large facial feature structure and the recessed platform structure, thereby obtaining the large facial feature.

4. The molding process method for carbon fiber structural components according to claim 3, characterized in that, The hot pressing temperature of the first hot pressing is higher than the melting temperature of the thermoplastic resin; The hot pressing temperature of the second hot pressing is higher than the softening temperature of the thermoplastic resin.

5. The molding process method for carbon fiber structural components according to claim 1 or 3, characterized in that, Laying the carbon fiber prepreg in a hot press mold includes: The carbon fiber prepreg is laid in multiple layers in the hot press mold using a layering method.

6. The molding process method for carbon fiber structural components according to claim 5, characterized in that, The carbon fibers in the same layer of carbon fiber prepreg are arranged in one of the following ways: unidirectional arrangement, two-dimensional fabric, three-dimensional fabric, or multi-axial fabric. The two-dimensional fabric includes plain weave fabric, twill weave fabric or satin weave fabric, and the three-dimensional fabric includes orthogonal structure, corner interlocking structure fabric or multi-layer connection structure.

7. The molding process method for carbon fiber structural components according to claim 6, characterized in that, The stacking method includes at least one of parallel stacking, orthogonal stacking, or staggered stacking.

8. The molding process method for carbon fiber structural components according to claim 7, characterized in that, In the carbon fiber prepreg, all carbon fibers are of the first fiber type; or, The carbon fiber prepreg uses a variety of mixed fiber prepregs, and the fiber types of the mixed fiber prepregs include the first fiber and the second fiber; Multiple layers of the aforementioned carbon fiber prepreg form a composite material stack, wherein all of the composite material stacks use the aforementioned carbon fiber prepreg, or a mixed stack formed by the aforementioned carbon fiber prepreg and the aforementioned mixed fiber prepregs; The first fiber includes one of viscose-based carbon fiber, PAN-based carbon fiber, or pitch-based carbon fiber; the second fiber includes one of glass fiber, ceramic fiber, alumina fiber, basalt fiber, aramid fiber, PBO fiber, polyarylate fiber, graphite fiber, or carbon nanotube fiber.

9. The molding process method for carbon fiber structural components according to claim 8, characterized in that, The recessed platform structure is formed by the surface of the large face being recessed inward; The carbon fibers in the large face are continuous, and the carbon fibers have a regular arrangement and orientation; The fibers adjacent to the sinking structure are spaced apart from the sinking structure.

10. The molding process method for carbon fiber structural components according to claim 9, characterized in that, The large facial feature structure includes at least one of the following: step, arc surface, R angle, and C angle; The surface of the recessed platform structure includes at least one of the following: planar, serrated, grid-like, columnar, and prismatic protrusions. The structural component includes at least one of a snap fastener, a stud, and a groove.

11. The molding process method for carbon fiber structural components according to claim 2, characterized in that, Before the injection molding of the structural part at the settling platform structure, the method further includes: The surface of the sinking platform structure is treated by cleaning, laser engraving, and plasma treatment.

12. The molding process method for carbon fiber structural components according to claim 11, characterized in that, Before the injection molding of the structural part at the settling platform structure, the method further includes: The recessed platform structure of the large face is preheated using directional heating; or, A large-area overall heating method is used to preheat the entire large face. The preheating temperature is higher than the softening temperature of the thermoplastic resin.

13. The molding process method for carbon fiber structural components according to claim 12, characterized in that, The injection molding material matrix is ​​made of thermoplastic resin; The thermoplastic resin system of the injection molding material matrix is ​​the same as that of the carbon fiber prepreg.

14. A molding process for carbon fiber structural components, characterized in that, include: Provide carbon fiber prepreg; The carbon fiber prepreg is laid in a first hot press mold and subjected to a first hot press molding process to obtain a carbon fiber sheet; wherein, the surface of the first hot press mold is flat and the surface of the carbon fiber sheet is flat. The carbon fiber sheet is placed in a hot-press injection mold to integrally form the large facial structural features and injection-molded structural parts, thereby obtaining a carbon fiber structural component.

15. The molding process method for carbon fiber structural components according to claim 14, characterized in that, The step of placing the carbon fiber sheet into a hot-press injection mold to form the large facial structural features and the injection-molded structural part includes: The carbon fiber sheet is placed in a hot-press injection molding mold, and the carbon fiber sheet is subjected to a second hot-press molding using the hot-press injection molding mold to form the large facial feature structure. The injection material is melted using the hot-press injection mold and then injected into the injection position of the carbon fiber sheet to form the structural part.

16. The molding process method for carbon fiber structural components according to claim 15, characterized in that, The carbon fiber prepreg is formed by impregnating carbon fibers with thermoplastic resin. The hot pressing temperature of the first hot pressing is higher than the melting temperature of the thermoplastic resin; The second hot pressing temperature is higher than the softening temperature of the thermoplastic resin.

17. A carbon fiber structural component, characterized in that, The carbon fiber structural component is manufactured using the molding process method described in any one of claims 1-16, wherein the carbon fiber structural component comprises: A large face (100) has a surface including a large face feature structure (101) and a settling platform structure (102). The interior of the large face (100) includes multiple layers of carbon fibers (103). The carbon fibers (103) are continuous and have a regular arrangement and orientation. The carbon fibers (103) include a first fiber and / or a second fiber. A structural portion (200) is injection molded into the recessed structure (102), the bottom of the structural portion (200) being spaced from the first or second fiber of the adjacent layer in the large surface area (100).

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