Method for integrally forming carbon fiber structural part of sunken mouth frame

Abstract

The present disclosure relates to the technical field of composite material load-bearing structure forming, and particularly relates to a carbon fiber structure integrated forming method of a sunken mouth frame. The present disclosure provides a carbon fiber structure integrated forming method of a sunken mouth frame, which comprises overall layering, folding the skin fiber multiple times, layering the mouth frame by using the folded skin fiber, forming the sunken mouth frame, the reinforcing area and the skin layering, pre-pressing the product after layering by using a mold and curing the skin shape, curing and forming, taking the product out of the furnace after curing, removing the process skin on the outside, demolding by using a demolding tool, detecting and processing the end face and the opening of the product, and the like. The technical scheme of the present disclosure solves the problem of the integrated forming of the sunken mouth frame structure carbon fiber shell, guarantees the overall continuity of the fiber to the greatest extent, and improves the load-bearing capacity of the shell structure.

Description

Technical Field

[0001] This disclosure relates to the field of composite material load-bearing structural component molding technology, and in particular to a method for integral molding of carbon fiber structural components with a recessed frame. Background Technology

[0002] The recessed frame of the carbon fiber composite shell serves to support the overall strength and also meets certain load-bearing requirements. If an adhesive bonding process is used here, molding the shell and frame separately and then bonding them together, the structural component will have low strength, failing to meet product design requirements and compromising the internal quality of the product. Furthermore, if the final product has excessively large and dense openings, machining the openings after integral molding will damage the internal quality of the product and introduce processing stress that could cause deformation and compromise the contours. Summary of the Invention

[0003] This disclosure aims to address at least one of the technical problems existing in the prior art or related technologies.

[0004] Therefore, this disclosure provides a method for integral molding of a carbon fiber structural component with a recessed frame, characterized by comprising:

[0005] The overall lay-up involves folding the skin fibers multiple times and then layering the frame using the folded skin fibers.

[0006] The recessed frame, reinforcing zone and skin are laid up and formed. After the layup is completed, the product is pre-pressed in the mold and the skin is shaped and cured.

[0007] After curing and molding, the product is removed from the oven, and the outer layer of the process skin is removed.

[0008] Demolding process, which uses demolding tools to remove the product from the mold;

[0009] Inspection and processing, including the end faces and openings of the products.

[0010] In one feasible implementation, the mold pre-pressing is performed using vacuum hot pressing, wherein the hot pressing temperature is set to 100°C to 130°C, the process is pressurized to 0.6 MPa, and the pressurization and depressurization rate is 20 kPa / min.

[0011] In one feasible implementation, mechanical pressure is applied to the recessed frame before the vacuum hot pressing.

[0012] In one feasible implementation, the temperature rise regime for the skin shaping and curing is 200°C to 240°C, the total temperature rise and fall rate is 60±5°C / h, and the process pressure is increased to 0.6MPa.

[0013] In one feasible implementation, the process pressurization rate is 20 kPa / min and the depressurization rate is 10 kPa / min.

[0014] In one feasible implementation, the skin fibers are folded multiple times, which are divided into 0° fiber folding and 45° fiber folding.

[0015] In one feasible implementation, when the skin fibers are folded from the end frame to the skin, the fold overlap width is less than or equal to 1 mm.

[0016] In one feasible implementation, the seam gap of the skin fibers is set to 50±10 mm when they are folded multiple times.

[0017] In one feasible implementation, the seam gaps are filled with prepreg.

[0018] In one feasible implementation, the cutting direction of the skin fiber folding layer is consistent with the fiber direction.

[0019] The above description is merely an overview of the technical solution provided in this disclosure. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other features and effects of this disclosure more obvious and understandable, the following are specific examples of the implementation methods of this disclosure. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0021] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0023] Figure 1 This is a schematic diagram of the structure of the present disclosure with a 45° fiber orientation;

[0024] Figure 2 This is a schematic diagram of the structure in the 0° fiber direction of this disclosure.

[0025] in, Figure 1and Figure 2 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0026] 1-Fiber orientation. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0028] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0029] Currently, the recessed frame of the carbon fiber composite shell serves to support the overall strength and also meets certain load-bearing requirements. If an adhesive bonding process is used here, molding the shell and frame separately and then bonding them together, the structural component will have low strength, failing to meet product design requirements and compromising the internal quality of the product. Furthermore, if the final product has excessively large and dense openings, machining the openings after integral molding will damage the internal quality of the product and introduce processing stress that could cause deformation and compromise the contours.

[0030] Based on this, the present disclosure provides a method for integral molding of carbon fiber structural components with a recessed mouth frame. The skin fiber is folded multiple times, and the folded skin fiber is used to lay up the mouth frame in layers to ensure the continuity of the internal fibers during product preparation. This improves the load-bearing capacity of the structural compartment and the integrity of the product shape. The process skin is used for shape curing. The process skin with lower rigidity is used instead of a rigid mold, which can better cover the outer surface of the product during the curing process and avoid the deviation of the outer contour caused by assembly interference due to the rigid mold.

[0031] The following detailed description uses specific embodiments to illustrate the method for integral molding of the carbon fiber structural component of the recessed frame:

[0032] Reference Figures 1 to 2 As shown, this disclosure provides a method for integral molding of a carbon fiber structural component with a recessed frame, including:

[0033] The overall lay-up involves folding the skin fibers multiple times and then layering the frame using the folded skin fibers.

[0034] The recessed frame, reinforcing zone and skin are laid up and formed. After the layup is completed, the product is pre-pressed in the mold and the skin is shaped and cured.

[0035] After curing and molding, the product is removed from the oven, and the outer layer of the process skin is removed.

[0036] Demolding process, which uses demolding tools to remove the product from the mold;

[0037] Inspection and processing, including the end faces and openings of the products.

[0038] This disclosure involves repeatedly folding the skin fibers and layering the folded skin fibers onto the frame to ensure the continuity of the internal fibers during product preparation. This improves the load-bearing capacity of the structural compartment and the integrity of the product shape. Furthermore, the process skin is used for shaping and curing. By using a less rigid process skin instead of a rigid mold, it can better adhere to the outer surface of the product during the curing process and avoid assembly interference caused by a rigid mold, which could lead to deviations in the outer contour.

[0039] Specifically, based on the product's structural characteristics, a molding die is designed. The main body of the die is made of steel punch, which serves as an internal support. Its feature is that, while satisfying the functions of layup and rotation, it utilizes a movable block design to achieve the overall demolding function of carbon fiber structural components with a recessed frame.

[0040] The structural components manufactured in this disclosure take carbon fiber composite materials as an example. The carbon fiber composite materials are formed using unidirectional prepreg layup. During the layup design, to ensure the overall fiber continuity of the product, especially the continuity between the recessed frame and the large-area skin, the skin fibers are folded, and the folded fibers are used to lay up the frame. However, there is a difference in thickness between the skin and the recessed frame. If all the skin fibers are folded up for frame layup, the frame thickness will be too thick. If further compression and physical pressure curing are applied in the mold, a large amount of resin will be lost, altering the fiber volume content and causing internal quality problems. Therefore, considering the design safety factor and ensuring the overall continuity of the junction between the skin and frame, a local layup design is required. The skin fibers are folded multiple times in batches to reduce the accumulation of excess fibers in the frame and maximize fiber continuity. It should be noted that the fibers in the commonly used fiber prepreg are unidirectional. At the corners of the mold tooling, to ensure fiber continuity, folding is used to allow the fibers to conform to the mold surface for layup.

[0041] After the product has been laid up, it needs to be pre-pressed in a rigid mold and cured in a skin shape, both of which are carried out by pressurizing in a vacuum-assisted autoclave.

[0042] Our company uses flexible molds for skin curing, which have better extensibility and elasticity than rigid molds. The shape can be selected according to the product's adaptability. During the pressing process, the flexible mold can better fit the product surface, ensuring that the force is evenly distributed in all corners of the product. It can also avoid pressure transmission failure caused by the product not fitting the mold properly in some complex structural areas due to the excessive rigidity of the rigid mold.

[0043] After the product has cured, the vacuum-sealed material on the mold surface is removed, the outer layer of the process skin is removed, and finally, the product is completely removed from the mold using the anti-screw and the opening frame punch block to obtain the carbon fiber composite material section. Finally, the end face and opening of the product are machined.

[0044] In some embodiments, the mold pre-pressing is performed using vacuum hot pressing, wherein the hot pressing temperature is set to 100°C to 130°C, the process is pressurized to 0.6 MPa, and the pressurization and depressurization rate is 20 kPa / min.

[0045] In this embodiment, the present disclosure can use a vacuum autoclave for hot pressing, and the hot pressing temperature is set to 100°C to 130°C. Below 100°C, the prepreg and resin flow state cannot be achieved, resulting in internal air bubbles and quality problems. Above 130°C, the viscosity is too high, which is not conducive to molding.

[0046] In some embodiments, mechanical pressure is applied to the recessed frame before the vacuum hot pressing to allow the fibers to better conform to the mold.

[0047] In some embodiments, the temperature rise regime for the skin shaping curing is 200°C to 240°C, the total temperature rise and fall rate is 60±5°C / h, and the process pressure is increased to 0.6MPa.

[0048] In this embodiment, the present disclosure sets the curing temperature for the skin to 200°C to 240°C. Within this temperature range, the resin and curing agent react to produce a cross-linking reaction, thereby achieving resin curing. The resin curing process is a chemical reaction. Only when the temperature reaches the curing temperature does the molecule possess sufficient energy to overcome the energy barrier of the reaction, allowing the curing reaction to proceed at a considerable rate. If the temperature is below the curing temperature of 200°C, the molecular kinetic energy is insufficient, the reaction rate is extremely slow, and the curing phenomenon is almost imperceptible. Temperatures that are too high, such as 240°C, accelerate the curing speed, but a temperature difference will exist between the internal and external temperatures, thereby generating internal stress.

[0049] In some embodiments, the process pressurization rate is 20 kPa / min and the depressurization rate is 10 kPa / min. The pressurization and depressurization rates are mainly related to the characteristics of the resin. The pressurization rate is to allow sufficient time for the resin to expel internal air bubbles before it is fully cured, while the depressurization rate is for better shape retention.

[0050] In some embodiments, the skin fibers are folded multiple times, including 0° fiber folding and 45° fiber folding. The 0° and 45° folds ensure fiber continuity and guarantee the mechanical strength of the product.

[0051] In some embodiments, when the skin fibers are folded from the end frame to the skin, the folding overlap width is less than or equal to 1 mm to ensure that the fiber folding is continuous and does not occupy unnecessary space due to excessive overlap, which would cause excessive internal stress in the product.

[0052] In some embodiments, the seam gaps between the multiple folds of the skin fibers are set to 50 ± 10 mm. Furthermore, the seam gaps are filled with prepreg to ensure the overall continuity of the fibers.

[0053] In some embodiments, the cutting direction of the skin fiber folding layer is consistent with the fiber direction.

[0054] In this disclosure, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0055] In the description of this disclosure, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0056] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0057] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for integrally molding a carbon fiber structural component with a recessed mouth frame, characterized in that, include: The overall layup involves folding the skin fibers in batches multiple times, and then layering the folded skin fibers with the mold face to form the face frame. The skin fibers refer to unidirectional carbon fiber prepreg tape. The recessed frame, reinforcing zone and skin are laid up and formed. After the layup is completed, the product is pre-pressed in the mold and the skin is shaped and cured. After curing and molding, the product is removed from the oven, and the outer layer of the process skin is removed. Demolding process, which uses demolding tools to remove the product from the mold; Inspection and processing, including the end faces and openings of the processed products.

2. The method for integral molding of carbon fiber structural components for recessed frames according to claim 1, characterized in that, The mold pre-pressing adopts vacuum hot pressing, wherein the hot pressing temperature is set to 100℃ to 130℃, the process is pressurized to 0.6MPa, and the pressurization and depressurization rate is 20KPa / min.

3. The method for integral molding of carbon fiber structural components for recessed frames according to claim 2, characterized in that, Before the vacuum hot pressing, mechanical pressure is applied to the recessed frame.

4. The method for integral molding of carbon fiber structural components for recessed frames according to claim 1, characterized in that, The curing temperature regime for the skin is 200℃ to 240℃, with a total heating and cooling rate of 60±5℃ / h, and the process is pressurized to 0.6MPa.

5. The method for integral molding of carbon fiber structural components for recessed mouth frames according to claim 4, characterized in that, The pressurization rate of the process is 20 kPa / min, and the depressurization rate is 10 kPa / min.

6. The method for integral molding of carbon fiber structural components for recessed frames according to claim 1, characterized in that, The skin fibers are folded multiple times, including 0° fiber folding and 45° fiber folding.

7. The method for integral molding of carbon fiber structural components for recessed frames according to claim 1, characterized in that, When the skin fibers are folded from the end frame to the skin, the fold overlap width is less than or equal to 1 mm.

8. The method for integral molding of carbon fiber structural components for recessed frames according to claim 1, characterized in that, The seam gap of the skin fiber is set to 50±10 mm after multiple folds.

9. The method for integral molding of carbon fiber structural components for recessed frames according to claim 8, characterized in that, The gaps between the splices are filled with prepreg.

10. The method for integral molding of carbon fiber structural components for recessed frames according to claim 1, characterized in that, The cutting direction of the skin fiber folding and layup is consistent with the fiber direction.

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