Core mold thermal expansion process

Abstract

The invention discloses a core mold thermal expansion technology which comprises the following technological processes: S1, manufacturing a core mold: manufacturing a core mold with the volume smaller than that of a product by 5% according to the appearance shape of the product, and cutting the core mold into six blocks; s2, laying: laying carbon fiber prepreg in a mold cavity of a metal mold, putting the core mold in sequence, laying the carbon fiber prepreg on the top of the metal mold, connecting the metal mold into a whole, and closing a core-pulling window; s3, curing is conducted according to the curing curve of the material, and demolding is conducted after curing is completed; and S4, demolding is conducted, specifically, the sealing plate at the core-pulling window is dismantled, the mold core in the core-pulling window is pulled out, then the metal mold is decomposed, and the product is taken out. According to the core mold thermal expansion technology, it can be guaranteed that stress of the composite material is uniform, dead corners are avoided, meanwhile, parting lines are prevented from being left on the composite material, the integrity and attractiveness of the product are guaranteed, and the fatigue life of the composite material is prolonged.

Description

Technical Field

[0001] This invention relates to the field of composite material manufacturing technology, specifically a mandrel thermal expansion process. Background Technology

[0002] The mandrel thermal expansion process is a composite material molding technology that uses the thermal expansion of the mandrel material during heating to apply internal pressure to the composite material blank, thereby achieving its compaction and curing.

[0003] Because composite materials have higher strength and stiffness than ordinary materials, the following problems are prone to occur in the traditional manufacturing process: (1) Uneven pressure and difficulty in eliminating dead corners: Traditional rigid molds or external pressure methods are difficult to effectively transmit uniform pressure to every corner of the complex structure, which can easily lead to insufficient resin impregnation and low fiber volume fraction (Vf<50%), resulting in defects such as dry spots, pores, and resin-rich areas, which seriously affect the mechanical properties and reliability of the product; (2) Parting lines and splicing hazards: In order to remove the rigid core mold, the mold usually needs to be designed with a parting surface, which will leave parting lines on the surface of the product or require subsequent splicing. This not only affects the structural integrity and aesthetics, but also becomes a stress concentration point, reducing the fatigue life of the component. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide a core mold thermal expansion process that can ensure uniform stress on the composite material, avoid dead corners, and avoid leaving parting lines on the composite material, thus ensuring the integrity and aesthetics of the product and effectively solving the problems in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a core mold thermal expansion process, comprising the following process flow:

[0006] S1: Making the core mold:

[0007] Based on the product's appearance and shape, create a core mold that is 5% smaller than the product's volume, and cut it into six pieces;

[0008] S2: Layup:

[0009] Carbon fiber prepreg is laid in the cavity of the metal mold, and the core mold is placed in sequence. Carbon fiber prepreg is also laid on the top of the metal mold. The metal molds are connected as a whole and the core-pulling window is closed.

[0010] S3: Curing is performed according to the material's curing curve; demolding is completed after curing.

[0011] S4: Demolding:

[0012] First, remove the sealing plate at the core-pulling window, pull out the internal mold core, then disassemble the metal mold and remove the product.

[0013] As a preferred embodiment of the present invention, the core mold in step S1 is made of special silicone.

[0014] As a preferred embodiment of the present invention, in step S1, after the core mold is cut into six pieces, each piece can be pulled out at the core-pulling window.

[0015] As a preferred embodiment of the present invention, the metal mold includes:

[0016] Chassis;

[0017] Two C-shaped blocks are symmetrically installed on the upper surface of the chassis near the edge, and the two C-shaped blocks form a circular outer wall.

[0018] A central column is installed at the middle position of the upper end face of the chassis, and the height of the central column is the same as the height of the C-shaped block;

[0019] A pull-out window is located on the outside of one of the C-shaped blocks;

[0020] The top cover is installed on the upper end of the C-shaped block.

[0021] As a preferred embodiment of the present invention, a removable sealing plate is installed at the core-pulling window.

[0022] As a preferred embodiment of the present invention, the lower end face of the top cover is provided with an overlapping ring that overlaps with the central column, and the overlapping ring consists of two rings, one large and one small.

[0023] As a preferred embodiment of the present invention, the chassis, C-block, central column, top cover and sealing plate are all detachably connected by bolts.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: During the heating process, the core mold expands due to heat, thereby continuously and uniformly extruding the prepreg material outward, achieving compaction from the inside out, and uniformly transmitting pressure to every corner; at the same time, both the core mold and the metal mold are designed as detachable structures, so that no parting line is left on the product surface when the core mold is removed, ensuring the integrity and aesthetics of the product, and extending the fatigue life of the composite material. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the core mold structure;

[0026] Figure 2 This is a schematic diagram of the structure of a metal mold;

[0027] Figure 3 A schematic diagram showing the placement of the core mold into the metal mold;

[0028] Figure 4 This is a schematic diagram of a closed metal mold.

[0029] Figure 5 A schematic diagram of a completely enclosed metal mold;

[0030] Figure 6 This is a schematic diagram of the structure after the mold core has been extracted;

[0031] Figure 7 This is a schematic diagram of the structure after the mold core has been completely extracted;

[0032] Figure 8 This is a schematic diagram of the structure after disassembling the metal mold;

[0033] Figure 9 This is a schematic diagram of the product that was removed.

[0034] In the diagram: 1 Core mold, 2 Metal mold, 21 Chassis, 22 C-block, 23 Central column, 24 Pull-out window, 25 Top cover, 26 Overlap ring, 27 Sealing plate. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please see Figure 1-2 The present invention provides a technical solution: a core mold thermal expansion process, including a core mold 1 and a metal mold 2 required for producing composite materials;

[0037] The metal mold 2 includes a base 21, C-shaped blocks 22, a central column 23, a core-pulling window 24, and a top cover 25. There are two C-shaped blocks 22, which are symmetrically installed on the upper surface of the base 21 near the edge. The two C-shaped blocks 22 form a circular outer wall.

[0038] The central column 23 is installed in the middle of the upper end face of the chassis 1. The height of the central column 23 is the same as the height of the C-shaped block 22. The central column 23 is a cylindrical structure with an internal cavity.

[0039] The core-pulling window 24 is located on the outside of one of the C-shaped blocks 22. The core-pulling window 24 has a rectangular structure and a removable sealing plate 27 is installed at the core-pulling window 24.

[0040] The top cover 25 is installed on the upper end of the C-shaped block 22.

[0041] To facilitate the assembly and disassembly of the metal mold 2, the chassis 21 is connected to the C-block 22 and the central column 23 by bolts, the two C-blocks 22 are connected to each other by bolts, the top cover 25 is connected to the C-block 22 by bolts, and the sealing plate 27 is connected to the core-pulling window 24 by bolts.

[0042] To facilitate the overlap between the top cover 25 and the C-shaped block 22, the lower end face of the top cover 25 is provided with an overlap ring 26 that overlaps with the central column 23. There are two overlap rings 26, one large and one small, which correspond to the inner and outer rings of the central column 23, respectively.

[0043] like Figure 3-9 The manufacturing process for composite materials is as follows:

[0044] S1: Making Core Mold 1:

[0045] Based on the product's appearance and shape, make a core mold 1 that is 5% smaller than the product's volume. The core mold 1 is made of special silicone and cut into six pieces, ensuring that each piece can be pulled out at the core-pulling window 24.

[0046] S2: Layup:

[0047] Carbon fiber prepreg is laid in the cavity of metal mold 1, and core mold 1 is placed in sequence. The top cover 25 of metal mold 2 is also laid with carbon fiber prepreg. After the overlapping parts are properly treated, metal mold 1 is connected into a whole and core-pulling window 24 is closed.

[0048] S3: Curing is performed according to the material's curing curve; demolding is completed after curing.

[0049] S4: Demolding:

[0050] First, remove the sealing plate 27 at the core-pulling window 24, pull out the internal mold core, then disassemble the metal mold 2 and take out the product.

[0051] The parts of the invention not described in detail are prior art. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A core mold thermal expansion process, characterized in that: The process includes the following steps: S1: Making the core mold (1): Based on the product's appearance and shape, make a core mold (1) that is 5% smaller than the product's volume and cut it into six pieces; S2: Layup: Carbon fiber prepreg is laid in the cavity of the metal mold (1), and the core mold (1) is placed in sequence. Carbon fiber prepreg is also laid on the top of the metal mold (2). The metal mold (1) is connected as a whole and the core-pulling window (24) is closed. S3: Curing is performed according to the material's curing curve; demolding is completed after curing. S4: Demolding: First, remove the sealing plate (27) at the core-pulling window (24), pull out the internal mold core, then disassemble the metal mold (2) and take out the product.

2. The core mold thermal expansion process according to claim 1, characterized in that: In step S1, the core mold (1) is made of special silicone.

3. The core mold thermal expansion process according to claim 1, characterized in that: In step S1, after the core mold (1) is cut into six pieces, each piece can be pulled out at the core-pulling window (24).

4. The core mold thermal expansion process according to claim 1, characterized in that: The metal mold (2) includes: Chassis (21); Two C-shaped blocks (22) are symmetrically installed on the upper surface of the chassis (21) near the edge, and the two C-shaped blocks (22) form a circular outer wall. A central column (23) is installed at the middle position of the upper end face of the chassis (1), and the height of the central column (23) is the same as the height of the C-shaped block (22); A core-pulling window (24) is located on the outside of one of the C-shaped blocks (22); The top cover (25) is installed on the upper end of the C-shaped block (22).

5. The core mold thermal expansion process according to claim 4, characterized in that: A removable sealing plate (27) is installed at the core-pulling window (24).

6. The core mold thermal expansion process according to claim 4, characterized in that: The lower end face of the top cover (25) is provided with an overlapping ring (26) that overlaps with the central column (23), and there are two overlapping rings (26), one large and one small.

7. The core mold thermal expansion process according to claim 5, characterized in that: The chassis (21), C-block (22), central column (23), top cover (25) and sealing plate (27) are all detachably connected by bolts.

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