Forming method of composite material foam sandwich structural member and sandwich member foaming mold

Abstract

The invention relates to a forming method of a composite material foam sandwich structural member and a sandwich member foaming mold, and belongs to the field of composite material manufacturing. A forming method of a composite material foam sandwich structural member comprises the following steps: (1) customizing a composite material foam sandwich member pressure equalizing plate forming die and a sandwich member foaming die; (2) manufacturing a semi-rigid rubber pressure equalizing plate by using a pressure equalizing plate forming mold; (3) the foaming powder and the metal piece are glued into a foaming core in a drying oven through a sandwich piece foaming mold; (4) paving an adhesive film, a glass fiber prepreg and a carbon fiber fabric prepreg on a foaming core formed by the metal piece and the foaming powder to prepare a part preform; and (5) carrying out vacuum bag assembling and packaging on the pressure equalizing plate and the part prefabricated body, and then integrally transferring the pressure equalizing plate and the part prefabricated body to an autoclave for curing and forming. The invention has the following advantages: the manufacturing cost is reduced; the overall manufacturing efficiency of parts is improved; the foaming quality of the foaming powder is improved; and the internal bonding quality of the part is ensured.

Description

TECHNICAL FIELD

[0001] The application relates to a forming method of a composite material foam sandwich structure part and a sandwich part foaming die, and belongs to the field of composite material manufacturing. BACKGROUND

[0002] Composite materials are widely used in the field of aerospace due to their excellent performance. A composite material foam sandwich structure part (hereinafter referred to as a sandwich part) is formed by gluing a whole cladding type composite material skin, a metal framework and a foam block. In the prior art, the commonly used forming method of the part is generally mold pressing forming, that is, the part is formed by using a combined die of an upper and lower mold structure on a hot press to complete the foaming and gluing process. The method has the following disadvantages in use: (1) In addition to the foaming block forming die and the part gluing forming die, a special composite material skin laying die needs to be customized, the number of dies is large, and the manufacturing cost is high; (2) In the heating process, the uneven heat conduction of different parts of the die to the hot press easily leads to poor foaming of the internal foam powder of the part; (3) The composite material skin and the foam core are glued and formed, and the cooperation between the overall shape of the part and the die cavity surface of the combined die is required to be high, and improper cooperation easily causes internal gluing quality problems of the part. SUMMARY

[0003] The application aims to provide a forming method of a composite material foam sandwich structure part and a sandwich part foaming die, which adopts oven foaming and hot press tank co-gluing forming to simplify the process flow.

[0004] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme: a forming method of a composite material foam sandwich structure part, comprising the following steps, (1) Customizing a composite material foam sandwich part pressure equalizing plate forming die and a sandwich part foaming die; (2) Using the pressure equalizing plate forming die to manufacture a semi-rigid rubber pressure equalizing plate; (3) Making the foam powder and the metal part glue into a foam core through the sandwich part foaming die in an oven; (4) Laying a glue film, a glass fiber prepreg and a carbon fiber fabric prepreg on the foam core formed by the metal part and the foam powder to manufacture a part preform; (5) Vacuum bag assembling and packaging the pressure equalizing plate and the part preform, and then transferring the whole to a hot press tank for curing forming.

[0005] Preferably, the sandwich part pressure equalizing plate forming die is a male die, and the die surface is manufactured based on the outer surface of the sandwich part.

[0006] Preferably, the sandwich part foaming die is a structure of an upper and lower mold, and the die surface is manufactured based on the outer surface of the foam core of the sandwich part.

[0007] Preferably, in step (2), forming the semi-rigid rubber pressure plate comprises the following steps, Step one, referring to the part edge line, lay a whole layer of glass fiber prepreg on the core sandwich pressure plate forming mold; Step two, according to the structural characteristics of the core sandwich, the first layer of glass fiber prepreg is divided along the vertex line; Step three, lay two layers of glass fiber prepreg on both side wing surface areas, and then continue to lay two whole layers of alpha rubber to form a pressure plate preform; Step four, place the pressure plate preform in a hot press tank and cure according to the process parameters of the glass fiber prepreg to form a semi-rigid rubber pressure plate.

[0008] Preferably, in step one and step three, the thickness of the glass fiber prepreg is 0.1mm.

[0009] Preferably, in step (3), forming the foamed core comprises the following steps, Step one, place the metal part with surface treatment on the lower mold of the core sandwich foaming mold; Step two, use positioning block I and positioning block II to accurately position the metal part, and evenly pour the foaming powder into each cavity of the metal part according to the theoretical amount, and at the same time, adjust the positioning block II at one end of the metal part to a freely sliding state; Step three, position the upper mold of the core sandwich foaming mold through the positioning pin; Step four, place the foaming mold containing the metal part and the foaming powder in an oven and foam according to the process parameters of the foaming powder to form a foamed core.

[0010] Preferably, in step (4), the part preform is made by the following steps, Step one, trim and clean the foamed core after demolding; Step two, wrap the part preform by sequentially laying adhesive film, glass fiber prepreg and carbon fiber fabric prepreg on the surface of the foamed core according to design requirements.

[0011] Another object of the present application is to provide a core sandwich foaming mold for forming a composite foam core structure as described above, which comprises an upper mold and a lower mold, positioning block I and positioning block II are arranged at both ends of the lower mold, positioning block I is connected with the lower mold through screws and cylindrical pins, positioning block II is connected with the lower mold through screws, and a gas guide hole is arranged on the upper mold corresponding to the foaming area.

[0012] Further, it further comprises a positioning pin arranged at the diagonal position of the lower mold, which is used to position the upper mold of the core sandwich foaming mold.

[0013] Compared with the prior art, the present application has the following advantages: 1. The number of tooling required for part forming is reduced, the process flow is simplified, and the manufacturing cost is reduced; 2. Multiple parts can be simultaneously foamed in an oven and co-bonded in a hot press tank to improve overall manufacturing efficiency; 3. Oven foaming allows the mold to be heated evenly, improving the foaming quality of the foam powder; 4. The hot press tank co-bonding forming uses a semi-rigid rubber pressure plate to replace the mold forming of the mold structure, reducing the requirement for high matching degree of the part and tool surface, and better ensuring the internal bonding quality of the part. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic view of a composite foam sandwich structure part in an embodiment of the present application; Figure 2 is a schematic view of a pressure plate forming mold structure in an embodiment of the present application; Figure 3 is a schematic view of a foaming mold structure in an embodiment of the present application; Figure 4 is Figure 3 A-A sectional view of Figures 1-4 In the figure, 1 is a lower mold, 2 is an upper mold, 3 is a positioning block I, 4 is a positioning block II, 5 is a screw, 6 is a positioning pin, 7 is a cylindrical pin, and 8 is a gas guide hole. DETAILED DESCRIPTION

[0015] The present application will be further described below with reference to the accompanying drawings Figures 1-4 A forming method for a composite foam sandwich structure part, as shown in Figure 1 , includes the following steps, (1) Selecting appropriate specifications of steel to make a sandwich part pressure plate forming mold, as shown in Figure 2 , the mold structure is a male mold, and the mold surface is manufactured based on the outer surface of the sandwich part; (2) Selecting appropriate specifications of steel to make a sandwich part foaming mold, as shown in Figure 3 , the mold is a structure of upper and lower molds, and the surface is manufactured based on the outer surface of the foaming core of the sandwich part. The lower mold 1 is provided with a positioning block I 3 and a positioning block II 4 on both ends, the positioning block I 3 is connected with the lower mold 1 through a screw 5 and a cylindrical pin 7, the positioning block II 4 is connected with the lower mold 1 through a screw 5, and the upper mold 2 is provided with a gas guide hole 8 corresponding to the foaming area; (3) On the sandwich part pressure plate forming die, refer to the part edge line to lay a whole layer of 0.1mm thick glass fiber prepreg first, according to the sandwich part structure characteristics, the first layer of glass fiber prepreg can be split along the vertex line, then two layers of 0.1mm thick glass fiber prepreg are laid on both sides of the wing surface area, then two whole layers of α rubber are laid to form the pressure plate preform, so that the pressure plate has certain ductility and rigidity; (4) The pressure plate preform is placed in the hot press tank to be cured and formed according to the process parameters of the glass fiber prepreg, to form the semi-rigid rubber pressure plate; (5) The surface treated metal part is placed on the lower die 1 of the sandwich part foaming mold, the metal part is accurately positioned by the positioning block I 3 and the positioning block II 4, and the foaming powder is poured into each cavity of the metal part according to the theoretical amount, at the same time, the positioning block II 4 at one end of the metal part is adjusted to be freely slidable, and the upper die 2 of the sandwich part foaming mold is positioned and closed by the positioning pin 6; (6) The foaming mold with the metal part and the foaming powder is placed in the oven to be foamed according to the process parameters of the foaming powder, to form the foaming core; (7) The foaming core after demolding is trimmed and cleaned, then the adhesive film, glass fiber prepreg and carbon fiber fabric prepreg are laid on the surface of the foaming core according to the design requirements to wrap the part preform; (8) The part preform with the surface coated demolding material is assembled with the pressure plate and packaged as a whole vacuum bag, then it is placed in the hot press tank for curing and forming, the curing process parameters are: temperature 120℃-130℃, pressure 0.25MPa-0.45MPa, holding time 2.0h-4.0h.

Claims

1. A method of forming a composite foam sandwich structure member, characterized by: It comprises the following steps, (1) order composite foam sandwich component pressure plate forming die and sandwich component foaming die; (2) using the pressure plate forming die to make semi-rigid rubber pressure plate; (3) through the sandwich component foaming die in the oven to make the foaming powder and metal component into a foaming core; (4) on the foaming core formed by the metal component and the foaming powder, the adhesive film, glass fiber prepreg and carbon fiber fabric prepreg are sequentially laid to make the part preform; (5) the pressure plate and the part preform are vacuum bag assembled and packaged, and then the whole is transferred to the autoclave for curing forming.

2. The method of forming a composite foam sandwich structure of claim 1, wherein: In step (1), the sandwich component pressure plate forming die is a male die, and the die surface is processed and manufactured based on the outer surface of the sandwich component.

3. The method of forming a composite foam sandwich structure of claim 1, wherein: In step (1), the sandwich component foaming die is a structure of upper and lower dies, and the surface is processed and manufactured based on the outer surface of the sandwich component foaming core.

4. The method of forming a composite foam sandwich structure of claim 1, wherein: In step (2), the semi-rigid rubber pressure plate is formed by the following steps, Step one, lay a whole layer of glass fiber prepreg on the sandwich component pressure plate forming die according to the part edge line; Step two, according to the structural characteristics of the sandwich component, the first layer of glass fiber prepreg is divided along the vertex line; Step three, lay two layers of glass fiber prepreg on both side surfaces, and then continue to lay two whole layers of α rubber to form the pressure plate preform; Step four, place the pressure plate preform in the autoclave and cure according to the process parameters of the glass fiber prepreg to form the semi-rigid rubber pressure plate.

5. The method of forming a composite foam sandwich structure of claim 4, wherein: In steps one and three, the thickness of the glass fiber prepreg is 0.1mm.

6. The method of forming a composite foam sandwich structure of claim 1, wherein: In step (3), the foaming core is formed by the following steps, Step one, place the metal component with surface treatment on the lower die of the sandwich component foaming die; Step two, use the positioning block I and the positioning block II to accurately position the metal component, and evenly pour the foaming powder into each cavity of the metal component according to the theoretical amount, and at the same time, adjust the positioning block II at one end of the metal component to a freely sliding state; Step three, position the upper die of the sandwich component foaming die through the positioning pin; Step four, place the foaming die with the metal component and the foaming powder in the oven and foam according to the process parameters of the foaming powder to form the foaming core.

7. The method of forming a composite foam sandwich structure of claim 1, wherein: In step (4), the part preform is made by the following steps, Step one, trim and clean the demolded foaming core; Step two, wrap the adhesive film, glass fiber prepreg and carbon fiber fabric prepreg on the surface of the foaming core according to the design requirements to make the part preform.

8. A sandwich part foaming mold for forming a composite foam sandwich structure part according to any one of claims 1-7, characterized in that: It comprises an upper die and a lower die, positioning block I and positioning block II are arranged at both ends of the lower die, positioning block I is connected with the lower die through screws and cylindrical pins, positioning block II is connected with the lower die through screws, and a gas guide hole is arranged on the upper die corresponding to the foaming area.

9. The sandwich foaming mold according to claim 8, wherein: It also includes a positioning pin, which is arranged at the diagonal position of the lower die and used for positioning the upper die of the sandwich component foaming die.

Images