A composite material sandwich structure loose piece and its manufacturing process

Abstract

The present invention relates to a loose piece of a composite material sandwich structure, which comprises a central layer, a metal embedded part, a strengthening layer and a surface layer. The strengthening layer wraps the central layer, and the surface layer is coated on the outer surface of the strengthening layer. The central layer, the strengthening layer and the surface layer are all composite materials. One end of the metal embedded part is embedded between the central layer and the strengthening layer, and the other end thereof passes through the strengthening layer and the end face is lower than or flush with the outer contour surface of the surface layer. The present invention also relates to a manufacturing process of the loose piece of the composite material sandwich structure. The purpose of the loose piece of the composite material sandwich structure and its manufacturing process is to solve the problems of weight reduction and profile accuracy of large-sized loose pieces.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material forming, and particularly relates to a composite material sandwich structure loose piece and a manufacturing process thereof. Background Art

[0002] A loose piece is a general term for a structure widely used in the mold industry. It is installed in a mold cavity and together with the mold cavity surface forms a cavity that conforms to the outer contour surface of the product, to solve problems such as difficult mold processing and manufacturing caused by the complex shape of the product and difficult product demolding.

[0003] Currently, many passenger cars and ships adopt an integrally formed composite material body or hull, and the molds for manufacturing the body or hull are getting larger and larger. In the production of large-sized molds, composite material molds have better applicability than metal molds. Whether the composite material mold shell adopts dry forming (prepreg) or wet forming (vacuum resin infusion), it belongs to typical additive manufacturing. This characteristic determines that composite material molds are more suitable for large-sized products with a continuously curved or tangentially continuous outer contour. At the parts where the outer contour of the product has a sudden change in curvature or a discontinuous tangent, or at the parts where the contour surface is concave or convex, using loose pieces to assist in forming the mold cavity becomes a solution. And for larger-sized loose pieces in composite material molds, two problems of weight reduction and surface machining accuracy need to be solved.

[0004] Therefore, the inventor provides a composite material sandwich structure loose piece and a manufacturing process thereof. Summary of the Invention

[0005] (1) Technical Problems to be Solved

[0006] The embodiments of the present invention provide a composite material sandwich structure loose piece and a manufacturing process thereof, which solve the technical problems of weight reduction and surface contour accuracy of large-sized loose pieces.

[0007] (2) Technical Solutions

[0008] The present invention provides a composite material sandwich structure loose piece, including a central layer, a metal embedded part, a strengthening layer, and a surface layer. The strengthening layer wraps the central layer, the surface layer is coated on the outer surface of the strengthening layer, and the central layer, the strengthening layer, and the surface layer are all composite materials;

[0009] One end of the metal embedded part is embedded between the central layer and the strengthening layer, and the other end passes through the strengthening layer and the end face is lower than or level with the outer contour surface of the surface layer.

[0010] Further, the central layer is made of high-density foam material.

[0011] Further, the central layer is provided with a groove for placing the metal embedded part.

[0012] Further, the reinforcing layer is made of glass fiber reinforced epoxy resin.

[0013] Further, the thickness of the reinforcing layer is 5 - 8 mm.

[0014] Further, the surface layer is a high-temperature resistant resin layer.

[0015] Further, the embedded metal part includes a cross-shaped root and a cylindrical part. The cylindrical part is fixed at the center of the cross-shaped root and has a threaded through-hole.

[0016] Further, the composite sandwich structure loose piece further includes a connecting piece. The connecting piece is arranged on the outer contour surface of the surface layer and is used to connect the mold.

[0017] The present invention also provides a manufacturing process for the above-mentioned composite sandwich structure loose piece, including the following steps:

[0018] Prepare the center layer. The center layer is processed by numerical control from high-density foam. The outer contour surface of the processed center layer is 15 - 18 mm lower than the final contour surface of the loose piece;

[0019] Prepare the metal embedded part and the connecting piece;

[0020] Apply structural adhesive to the grooves processed in the center layer, place the metal embedded part in the grooves of the center layer, and bond and cure;

[0021] Use glass fiber reinforced epoxy resin to fabricate the reinforcing layer by hand lay-up or vacuum infusion process, wrap the center layer and the metal embedded part together, and perform curing treatment. After curing, the thickness of the reinforcing layer is 5 - 8 mm;

[0022] Clean the surface of the cured reinforcing layer, apply a high-temperature resistant resin layer. After the high-temperature resistant resin layer is cured, its thickness is 8 - 15 mm higher than the final contour surface of the loose piece;

[0023] Numerically control process the cured high-temperature resistant resin layer to form the surface layer of the final loose piece;

[0024] Connect the connecting piece at the docking surface between the loose piece and the mold.

[0025] Further, when fabricating the reinforcing layer, ensure that the end face of the cylindrical part is not wrapped; when applying the high-temperature resistant resin layer, ensure that the end face of the cylindrical part is not coated.

[0026] (3) Beneficial effects

[0027] In summary, by using the sandwich structure movable block made of composite materials in the present invention, the weight of the large-volume movable block can be effectively reduced. The formed integral movable block is machined on the surface layer of the movable block by a numerical control machine tool. The numerical control machining is the last process for forming the final outer contour surface of the movable block. Therefore, there is no misalignment of the contour surface at the butt joint or bonding joint caused by butt joint or bonding, and the high precision of the outer contour surface improves the contour precision of the movable block, which can better solve the manufacturing difficulty of large movable blocks in large molds. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 is a schematic structural diagram of a sandwich structure movable block made of composite materials provided by an embodiment of the present invention;

[0030] Figure 2 is a schematic structural diagram of a metal embedded part in a sandwich structure movable block made of composite materials provided by an embodiment of the present invention.

[0031] In the figure:

[0032] 1 - central layer; 2 - metal embedded part; 201 - cruciform root; 202 - cylindrical part; 3 - strengthening layer; 4 - surface layer; 5 - connecting piece. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following further describes in detail the embodiments of the present invention in conjunction with the drawings and embodiments. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principle of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments, and covers any modifications, substitutions, and improvements of parts, components, and connection methods without departing from the spirit of the present invention.

[0034] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0035] Figure 1It is a schematic structural diagram of a movable block of a composite material sandwich structure provided by an embodiment of the present invention. The movable block may include a central layer 1, a metal embedded part 2, a strengthening layer 3, and a surface layer 4. The strengthening layer 3 wraps the central layer 1, and the surface layer 4 is coated on the outer surface of the strengthening layer 3. The central layer 1, the strengthening layer 3, and the surface layer 4 are all composite materials; one end of the metal embedded part 2 is embedded between the central layer 1 and the strengthening layer 3, and the other end thereof passes through the strengthening layer 3 and the end face is lower than or flush with the outer contour surface of the surface layer 4.

[0036] In the above embodiment, the central layer 1, the strengthening layer 3, and the surface layer 4 made of composite materials can reduce the weight of the movable block. The strengthening layer 3 can effectively increase the overall strength of the movable block and the fixing strength of the metal embedded part 2. The metal embedded part 2 can facilitate the lifting of the movable block and its connection with the mold.

[0037] As an optional embodiment, the central layer 1 is made of high-density foam material. Among them, selecting high-density foam as the central layer 1 of the movable block sandwich structure can minimize the weight of the movable block.

[0038] As an optional embodiment, the central layer 1 is provided with a groove for placing the metal embedded part 2. Among them, the opening of the groove can facilitate the rapid and accurate installation of the metal embedded part 2 inside the central layer 1.

[0039] As an optional embodiment, the strengthening layer 3 is made of glass fiber reinforced epoxy resin material. Among them, the strengthening layer 3 is formed by hand lay-up or vacuum infusion. This layer is used to wrap the cross-bottom root 201 of the central layer 1 and the metal embedded part 2, playing a role in fixing the metal embedded part 2 and increasing the overall strength of the movable block. At the same time, it is beneficial to the adhesion of the surface layer 4.

[0040] As an optional embodiment, the thickness of the strengthening layer 3 is 5 - 8 mm. Among them, the thickness of the strengthening layer 3 is based on the actual application scenario and experience. A thickness of 5 - 8 mm can not only ensure the overall strength of the movable block but also avoid an excessive increase in the overall weight of the movable block due to excessive thickness.

[0041] As an optional embodiment, the surface layer 4 is a high-temperature resistant resin layer. Among them, using a high-temperature resistant resin layer to make the surface layer 4 not only meets the requirement of the movable block for high temperature resistance during the production and use of the mold but also facilitates the numerical control machining to form a smooth and accurate outer contour surface.

[0042] As an optional embodiment, the embedded metal part 2 includes a cross-shaped root 201 and a cylindrical part 202. The cylindrical part 202 is fixed at the center of the cross-shaped root 201 and has a threaded through hole. Specifically, the opening of the threaded through hole can facilitate the connection between the movable block and the mold.

[0043] As an alternative embodiment, the composite sandwich structure loose piece further includes a connecting member 5, which is arranged on the outer contour surface of the surface layer 4 and is used to connect the mold. Among them, the connecting member 5 is made of metal or composite material, and is fixed on the surface layer 4 by means of bonding, screwing or riveting, and serves as the connection structure between the loose piece and the mold.

[0044] The embodiment of the present invention also provides a manufacturing process for the above-mentioned composite sandwich structure loose piece, including the following steps:

[0045] S100. Prepare the central layer. The central layer is processed by numerical control from high-density foam, and the outer contour surface of the processed central layer is 15-18 mm lower than the final contour surface of the loose piece;

[0046] S200. Prepare metal embedded parts and connecting members;

[0047] S300. Apply structural adhesive to the grooves processed in the central layer, place the metal embedded parts in the grooves of the central layer, and bond and cure;

[0048] S400. Use glass fiber reinforced epoxy resin to make the strengthening layer by hand lay-up or vacuum infusion process, wrap the central layer and the metal embedded parts together, and perform curing treatment. After curing, the thickness of the strengthening layer is 5-8 mm;

[0049] S500. Clean the surface of the cured strengthening layer, apply a high-temperature resistant resin layer, and the thickness of the high-temperature resistant resin layer after curing is 8-15 mm higher than the final contour surface of the loose piece;

[0050] S600. Numerically control the processed high-temperature resistant resin layer to form the surface layer of the final loose piece;

[0051] S700. Connect the connecting member to the docking surface between the loose piece and the mold.

[0052] In the above embodiment, in step S600, sufficient cutting allowance for numerical control machining should be reserved during the application construction of the high-temperature resistant resin mud, and it should be ensured that the outer contour surface of the surface layer is slightly higher than the end face of the cylindrical part of the metal embedded part after numerical control machining.

[0053] As an alternative embodiment, when making the strengthening layer, ensure that the end face of the cylindrical part is not wrapped; when applying the high-temperature resistant resin layer, ensure that the end face of the cylindrical part is not coated. Among them, when the cylindrical part is wrapped by the strengthening layer and / or coated with the surface layer, the threaded hole of the cylindrical part of the metal embedded part will be blocked, thereby losing the function of the metal embedded part.

[0054] It should be clear that the various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. And, for the sake of brevity, the detailed description of known methods and techniques is omitted here.

[0055] The above are only the embodiments of the present application and do not limit the present application. Without departing from the scope of the present invention, various changes and modifications can be made to the present application by those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A manufacturing process for a loose piece of a composite material sandwich structure, characterized in that, The loose piece of the composite material sandwich structure includes a central layer (1), a metal embedded part (2), a strengthening layer (3), and a surface layer (4). The strengthening layer (3) wraps the central layer (1), and the surface layer (4) is coated on the outer surface of the strengthening layer (3). The central layer (1), the strengthening layer (3), and the surface layer (4) are all composite materials; One end of the metal embedded part (2) is embedded between the central layer (1) and the strengthening layer (3), and the other end thereof passes through the strengthening layer (3) and the end face height is lower than or equal to the outer contour surface of the surface layer (4). This process includes the following steps: Prepare the central layer (1), which is numerically controlled processed from high-density foam. The outer contour surface of the processed central layer (1) is 15 - 18 mm lower than the final contour surface of the loose piece; Prepare the metal embedded part (2) and the connecting piece (5); Apply structural adhesive to the groove processed in the central layer (1), place the metal embedded part (2) in the groove of the central layer (1), and bond and cure; Use glass fiber reinforced epoxy resin to make the strengthening layer (3) by hand lay-up or vacuum infusion process, wrap the central layer (1) and the metal embedded part (2) together, and perform curing treatment. After curing, the thickness of the strengthening layer (3) is 5 - 8 mm; Clean the surface of the cured strengthening layer (3), apply a high-temperature resistant resin layer, and the thickness of the high-temperature resistant resin layer after curing is 8 - 15 mm higher than the final contour surface of the loose piece; Numerically control process the cured high-temperature resistant resin layer to form the surface layer (4) of the final loose piece; Connect the connecting piece (5) to the docking surface between the loose piece and the mold.

2. The manufacturing process of the loose piece of the composite material sandwich structure according to claim 1, characterized in that, When making the strengthening layer (3), ensure that the end face of the cylindrical part (202) is not wrapped; when applying the high-temperature resistant resin layer, ensure that the end face of the cylindrical part (202) is not coated.

3. The manufacturing process of the loose piece of the composite material sandwich structure according to claim 1, characterized in that, The metal embedded part (2) includes a cross-shaped root part (201) and a cylindrical part (202). The cylindrical part (202) is fixed at the center of the cross-shaped root part (201) and has a threaded through hole.

4. The manufacturing process of the loose piece of the composite material sandwich structure according to claim 1, characterized in that It also includes a connecting piece (5). The connecting piece (5) is arranged on the outer contour surface of the surface layer (4) and is used to connect the mold.

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