Molding Die and Molding Method for Composite Fairing Window

Abstract

The present invention provides a mold and molding method for a composite fairing window, comprising a mold base and a cylindrical protrusion, the cylindrical protrusion being disposed on the mold base and being covered with a heat-expandable silicone rubber. The side of the mold base provided with the cylindrical protrusion is flat, and the side of the mold base facing away from the cylindrical protrusion is curved. The heat-expandable silicone rubber covering the cylindrical protrusion expands upon heating, providing molding pressure on the side of the window during product preparation. This allows the size and molding quality of the fairing window portion to be controlled during the molding process, eliminating the need for subsequent processing. The resulting product has a smooth surface, high dimensional accuracy, and good internal quality of the composite material. The window molding mold can be placed in different locations within the fairing mold according to product requirements, helping to meet a variety of design needs.

Description

Technical Field

[0001] The present invention relates to the technical field of fairing molding, in particular to a molding die and molding method for a composite material fairing window, and more particularly to a method for lateral pressurization of an integral double-curvature molding window of a composite material fairing. Background Art

[0002] Glass fiber resin-based composite structural parts are lightweight and designable, and have good wave transmission capabilities. They have developed into one of the important cover structural parts in various communication antenna equipment.

[0003] However, for the window area in the overall double-curvature forming process of the fairing, due to its special shape, metal molds are currently mostly used for positioning. The mold is in direct contact with the product, and the side walls are trimmed and polished after forming to ensure the size of the product window area.

[0004] The existing Chinese patent application document with the publication number CN110001085B discloses a one-mold, two-cavity preparation method for a composite fairing with a spatial curved surface structure using the RTM process. The composite fairing with a spatial curved surface structure is mainly composed of a conical skin, a flange edge area 1, a web area and a flange edge area 2. The one-mold, two-cavity preparation method using the RTM process adopts a one-mold, two-cavity forming core mold block and flow channel design, including the following molding steps: cutting and numbering carbon fiber shaping fabrics; preparing a fairing preform; assembling the preform into a corresponding one-mold, two-cavity mold, continuing to lay the preform until the preparation of the preform is completed, and closing the mold; injecting resin into the RTM process for molding and curing; and demolding and cutting the product to obtain the finished product.

[0005] In the prior art, the production cycle of the fairing window is relatively long. When a metal mold is used, the product sidewall material cannot obtain sufficient molding pressure during the curing process, and the risk of internal defects is relatively high. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide a composite material fairing window forming mold and forming method.

[0007] According to the present invention, a composite material fairing window forming mold is provided, comprising a mold base and a cylindrical protrusion, wherein the cylindrical protrusion is arranged on the mold base and is covered with thermal expansion silicone rubber; the side of the mold base provided with the cylindrical protrusion is a flat surface, and the side of the mold base facing away from the cylindrical protrusion is an arcuate surface.

[0008] Preferably, the volume expansion of the heat-expandable silicone rubber is 0.2% / °C to 0.35% / °C, and the bulk elastic modulus of the heat-expandable silicone rubber is 100 MPa to 200 MPa.

[0009] Preferably, the diameter of the heat-expandable silicone rubber at the cylindrical protrusion is 300 ± 1 mm.

[0010] Preferably, the height of the heat-expandable silicone rubber at the cylindrical protrusion is higher than the inner surface of the cover.

[0011] Preferably, the side of the cylindrical protrusion away from the mold base is a plane.

[0012] Preferably, a positioning hole is provided on the cylindrical protrusion.

[0013] According to a method for forming a window of a composite fairing provided by the present invention, the forming method includes the following steps:

[0014] S1. Assemble the window forming mold on the overall mold and lay a release cloth on its surface;

[0015] S2. Lay the glass fiber resin prepreg on the mold. The glass fiber resin prepreg reserves a flange above the cylindrical protrusion of the window forming mold and the heat-expandable silicone rubber. Place a honeycomb core above the glass fiber resin prepreg surrounding the heat-expandable silicone rubber of the window forming mold. Place an annular preform outside the glass fiber resin prepreg on the surface of the heat-expandable silicone rubber, and lay the glass fiber resin prepreg above the honeycomb core;

[0016] S3. Flip up the glass fiber resin prepreg with the reserved flange and cover it on the inner surface of the product. Place a fiberglass equalizing plate on the inner surface of the product and the side of the window, and then place a vacuum bag to cover the product and the mold, and the composite fairing assembly is completed;

[0017] S4. Heat the assembled product and the mold together to the required curing temperature and apply the required pressure, and maintain the curing temperature and pressure until the glass fiber resin prepreg is cured, and a composite double-curvature fairing body with a window is obtained.

[0018] Preferably, the inner diameter of the annular preform is 302 ± 1 mm, and the wall thickness requirement is ≥ 1 mm.

[0019] Preferably, for step S4, put the assembled product and the mold into a hot press for heating and pressurization.

[0020] Preferably, the window forming mold can be assembled at any position of the overall mold according to the product requirements.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention provides window side molding pressure during product preparation by allowing the heat-expandable silicone rubber sleeved on the cylindrical protrusion to expand when heated. This allows the size of the fairing window portion and the molding quality of the portion to be controlled during the molding process without the need for subsequent processing. The resulting product has a smooth surface, high dimensional accuracy, and good internal quality of the composite material.

[0023] 2. The present invention helps to meet various design requirements by allowing the window forming mold to be placed at different positions of the fairing mold according to product requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0025] Figure 1 This is a schematic diagram of the assembly structure of the window forming mold and the overall mold of the present invention;

[0026] Figure 2 This is a schematic diagram showing the overall structure of a window forming mold according to the present invention;

[0027] Figure 3 This is a side view schematic diagram of the overall structure of the window forming mold mainly embodied in the present invention.

[0028] As shown in the figure:

[0029] cylindrical protrusion 1

[0030] Mold base 2

[0031] Thermal expansion silicone rubber 3 DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0033] like Figure 1 As shown, a mold for forming a composite fairing window according to the present invention includes a mold base 2 and a cylindrical protrusion 1. The cylindrical protrusion 1 is disposed on the mold base 2 and is covered with a thermally expandable silicone rubber 3. The side of the mold base 2 on which the cylindrical protrusion 1 is disposed is a flat surface, while the side of the mold base 2 facing away from the cylindrical protrusion 1 is an arcuate surface.

[0034] Specifically, the volumetric expansion of the thermally expandable silicone rubber 3 is 0.2% / °C to 0.35% / °C, and the bulk elastic modulus of the thermally expandable silicone rubber 3 is 100 MPa to 200 MPa. The diameter of the thermally expandable silicone rubber 3 at the cylindrical protrusion 1 is 300 ± 1 mm. The height of the thermally expandable silicone rubber 3 at the cylindrical protrusion 1 is higher than the inner surface of the cover.

[0035] More specifically, the side of the cylindrical protrusion 1 away from the mold base 2 is a plane. A positioning hole is provided on the cylindrical protrusion 1. The positioning hole penetrates into the cylindrical protrusion 1 from the side of the cylindrical protrusion 1 facing away from the mold base 2. The positioning hole is used to fix the internal metal embedment in the fairing cover body. The mold base 2 can be fixed to the overall mold through fasteners.

[0036] It should be noted that the specific dimensions of the window forming mold are determined according to the window dimensions required for the fairing.

[0037] According to the present invention, there is also provided a method for forming a window of a composite material fairing. Using the above-mentioned composite material fairing window forming mold, the forming method includes the following steps:

[0038] S1. Assemble the window forming mold on the overall mold and lay a release cloth on its surface. Assemble the thermally expandable silicone rubber 3 on the cylindrical protrusion 1, and then lay a release cloth on the mold surface.

[0039] S2. Lay the glass fiber resin prepreg on the mold. The glass fiber resin prepreg reserves a flange above the cylindrical protrusion 1 of the window forming mold and the thermally expandable silicone rubber 3. Place a honeycomb core above the glass fiber resin prepreg surrounding the thermally expandable silicone rubber 3 of the window forming mold. Place an annular preform outside the glass fiber resin prepreg on the surface of the thermally expandable silicone rubber 3, and lay the glass fiber resin prepreg above the honeycomb core.

[0040] Specifically, the inner diameter of the annular preform is 302 ± 1 mm, and the wall thickness requirement is ≥ 1 mm.

[0041] S3. Flip up the glass fiber resin prepreg with the reserved flange to cover the inner surface of the product. Place fiberglass equalizing plates on the inner surface of the product and the side of the window, and then place a vacuum bag to cover the product and the mold. The composite material fairing assembly is completed.

[0042] S4. Heat the assembled product and the mold together to the required curing temperature and apply the required pressure, and maintain the curing temperature and pressure until the glass fiber resin prepreg is cured, thus obtaining a composite material double-curvature fairing cover body with a window. Specifically, for step S4, place the assembled product and the mold in a hot press for heating and pressurization.

[0043] It should be noted that the window forming die can be assembled at any position of the overall die according to product requirements, and can meet various design needs. The heat-expandable silicone rubber 3 on the cylindrical protrusion 1 on the window forming die provides the pressure required for forming the window side wall, making the surface of the product flat, with high dimensional accuracy and good internal quality of the composite material.

[0044] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0045] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A forming method for a composite fairing window, characterized in that A composite material fairing window molding die is used, comprising a die base (2) and a cylindrical protrusion (1), wherein the cylindrical protrusion (1) is arranged on the die base (2), and a thermal expansion silicone rubber (3) is sleeved on the cylindrical protrusion (1); The side of the mold base (2) provided with the cylindrical protrusion (1) is a plane, and the side of the mold base (2) facing away from the cylindrical protrusion (1) is an arc-shaped surface; The molding method comprises the following steps: S1. Assemble the window forming mold on the overall mold and lay a release cloth on its surface; S2, laying the glass fiber resin prepreg on the mold, leaving a flange of the glass fiber resin prepreg to the top of the columnar protrusion (1) of the window molding mold and the heat-expanding silicone rubber (3), placing a honeycomb sandwich on the glass fiber resin prepreg surrounding the heat-expanding silicone rubber (3) of the window molding mold, placing an annular prefabricated block on the outside of the glass fiber resin prepreg on the surface of the heat-expanding silicone rubber (3), and laying the glass fiber resin prepreg on the honeycomb sandwich; S3. Fold up the glass fiber resin prepreg with the reserved flange and cover it on the inner surface of the product. Place a fiberglass reinforced plastic pressure plate on the inner surface of the product and the side of the window. Then place a vacuum bag to cover the product and the mold. The composite fairing is assembled. S4. The assembled product and the mold are heated to the required curing temperature and the required pressure is applied. The curing temperature and pressure are maintained until the glass fiber resin prepreg is completely cured, thereby obtaining a composite material double-curvature fairing body with a window.

2. The method for forming a composite fairing window according to claim 1, wherein The volume expansion of the heat-expandable silicone rubber (3) is 0.2% / °C to 0.35% / °C, and the volume elastic modulus of the heat-expandable silicone rubber (3) is 100MPa to 200MPa.

3. The method for forming a composite fairing window according to claim 1, wherein, The diameter of the heat-expanding silicone rubber (3) at the cylindrical protrusion (1) is 300±1 mm.

4. The method for forming a composite fairing window according to claim 1, characterized in that, The height of the heat-expanding silicone rubber (3) at the cylindrical protrusion (1) is higher than the inner surface of the cover.

5. The method for forming a composite fairing window according to claim 1, characterized in that, The side of the cylindrical protrusion (1) away from the mold base (2) is a plane.

6. The method for forming a composite fairing window according to claim 1, characterized in that A positioning hole is provided on the cylindrical protrusion (1).

7. The method for forming a composite fairing window according to claim 1, characterized in that, The inner diameter of the annular prefabricated block is 302±1 mm, and the wall thickness is required to be ≥1 mm.

8. The method for forming a composite fairing window according to claim 1, characterized in that In step S4, the assembled product and the mold are placed in an autoclave for heating and pressurizing.

9. The method for forming a composite fairing window according to claim 1, wherein The window forming mold can be assembled at any position of the overall mold according to product requirements.

Images