A molding die and method for forming a multi-cavity box-section structural beam of high aspect ratio composite material

Abstract

This invention discloses a molding die and method for forming a multi-cavity box-section beam structure made of composite material with a high aspect ratio. The bottom and side walls of the core assembly (1) are connected to the bottom support frame (2), the side support frame A (3), and the side support frame B (4), respectively. The core assembly (1) includes a base plate (5), a cavity core mold assembly (6) is provided on the upper surface of the base plate (5), a beam core mold assembly (7) is provided on the upper surface of the cavity core mold assembly (6), and side mold assemblies A (8) and B (9) are provided on both sides of the cavity core mold assembly (6) respectively, which can be aligned laterally. After the side mold assemblies A and B are aligned, they can surround the cavity core mold assembly (6), and the groove (10) formed at the top after alignment can limit the beam core mold assembly (7). After the side mold assemblies A and B are aligned, the top is covered with a top cover (11). This invention can ensure the molding quality of the product and can significantly reduce the manufacturing cost of similar products.

Description

Technical Field

[0001] This invention belongs to the field of composite material parts manufacturing technology, specifically relating to a molding die and method for forming a multi-cavity box-section structural beam of composite material with a large aspect ratio. Background Technology

[0002] High aspect ratio composite multi-cavity box-section structural beams are currently widely used in the horizontal tail structure and wing structure of fixed-wing aircraft. To meet development requirements, a new high aspect ratio composite multi-cavity box-section structural beam needs to be manufactured. The beam has an aspect ratio of 8400mm, twice the length of existing parts of the same type. It features a 12-cell closed-cavity structure, formed by 12 dimensional support ribs, an integral beam, and double-sided skins. (See attached diagram). Figure 8 , Figure 9 .

[0003] Currently, vacuum bag-autoclave molding and liquid molding are the two mainstream molding methods. However, both methods suffer from damage to parts due to the expansion of the mold caused by heat. The widely adopted solution is to use Invar steel, which has a smaller thermal expansion effect, for mold manufacturing. However, the cost and processing fees of Invar steel are more than 10 times higher than those of ordinary steel. Using Invar steel as the main material for part molds significantly increases the manufacturing cost of parts. Summary of the Invention

[0004] The purpose of this invention is to provide a molding die and method for forming multi-cavity box-section structural beams of high aspect ratio composite materials. This invention can ensure product molding quality and significantly reduce the manufacturing cost of similar products.

[0005] The technical solution of the present invention is: a molding die for a multi-cavity box-section structure beam made of composite material with a large aspect ratio, comprising: a core assembly, the bottom and side walls of which are respectively connected to a bottom support frame, a side support frame A and a side support frame B; the core assembly includes a base plate, a cavity core mold assembly is provided on the upper surface of the base plate, a beam core mold assembly is provided on the upper surface of the cavity core mold assembly, and side mold assemblies A and B, which can be laterally aligned, are respectively provided on both sides of the cavity core mold assembly. After the side mold assemblies A and B are aligned, they can surround the cavity core mold assembly, and the groove formed at the top after alignment can limit the beam core mold assembly; after the side mold assemblies A and B are aligned, the top is covered with a top cover.

[0006] In the aforementioned high aspect ratio composite multi-cavity box segment structure beam forming mold, the cavity core mold assembly includes a group of one or more core units arranged along the length direction of the substrate. The core unit includes a central block, and the two sides of the central block are connected by a mortise and tenon structure with side inserts A and B. The mortise and tenon structure can ensure that the central block can be pulled out from the bottom between the two inserts.

[0007] In the aforementioned high aspect ratio composite multi-cavity box segment beam forming mold, the sidewalls of the center block and the side inserts that contact each other are designed with draft angles.

[0008] In the aforementioned high aspect ratio composite multi-cavity box segment beam molding die, the core units located at both ends and the middle of the substrate are elastic cores.

[0009] In the aforementioned high aspect ratio composite multi-cavity box segment beam forming mold, the beam core mold assembly includes a group of one or more beam core units arranged along the length direction of the substrate. The beam core unit includes a pair of beam core inserts A and B that are laterally mated, and the mating surfaces of beam core inserts A and B are set at an angle.

[0010] In the aforementioned high aspect ratio composite multi-cavity box segment beam forming mold, the top surfaces of the beam core inserts A and B are respectively provided with locking module A and locking module B. After locking modules A and B are engaged, they cooperate with the locking groove provided on the bottom surface of the top cover.

[0011] In the aforementioned high aspect ratio composite multi-cavity box segment beam forming mold, the side mold components A and B are both frame beam structures.

[0012] The forming method of the aforementioned high aspect ratio composite multi-cavity box segment structure beam forming mold includes the following steps:

[0013] S1. Connect the center block, side inlay block A and side inlay block B with mortise and tenon structure to form core unit, and then lay the ribs of the multi-cavity box segment structure beam on the end face of the core unit.

[0014] S2. Install each core unit that has been laid out onto the substrate in sequence to form a cavity core mold assembly; lay the lower frame main beam of the multi-cavity box segment structure beam on the top surface of the cavity core mold assembly;

[0015] S3. Vacuum pre-compact the laid ribs and lower frame main beams;

[0016] S4. Assemble beam core inserts A and B to form beam core units, splice each beam core unit to form a beam core module assembly, and lay the upper frame main beam of the multi-cavity box segment structure beam on the beam core module assembly;

[0017] S5. Position and place the completed upper frame main beam, together with the beam core mold assembly, onto the top surface of the upper frame main beam;

[0018] S6. Lay the skin A and skin B of the multi-cavity box segment structural beam on the inner surfaces of the side mold components A and B respectively; after laying, the side mold components A and B are aligned so that the slots lock the beam core mold components from the side and fix them on the base plate.

[0019] S7. Attach the top cover to the top surface of the side mold components A and B after they are aligned, and make the locking groove cooperate with the aligned locking modules A and B to complete the assembly of the mold core components; after completion, install the bottom support frame, side support frame A and side support frame B around the mold core components;

[0020] S8. Inject resin into the mold core assembly for liquid molding.

[0021] The advantages of this invention are:

[0022] 1. This invention effectively solves the deformation effect caused by thermal expansion by using a split mold core assembly and a replaceable soft and hard mold. The mold of this invention, combined with the application of liquid molding technology, can ensure the product molding quality and significantly reduce the manufacturing cost of similar products.

[0023] 2. This invention adopts controllable thermal expansion mold design technology, and replaces the steel mold core on both sides and in the middle with a foam core material (elastic core) molding mold, thereby reducing the thermal expansion effect of the 8-meter product and solving the problem of product damage caused by mold thermal expansion. Attached Figure Description

[0024] Figure 1 It is a schematic diagram of the structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the core assembly structure;

[0026] Figure 3 A schematic diagram showing the connection between the cavity core mold assembly and the beam core mold assembly;

[0027] Figure 4 This is a schematic diagram of the side mold components A and B.

[0028] Figure 5 Schematic diagrams of the cavity core mold assembly and the beam core mold assembly;

[0029] Figure 6 Front view of the cavity core mold assembly and the beam core mold assembly;

[0030] Figure 7 This is a schematic diagram of the mating of side mold assembly A and side mold assembly B;

[0031] Figure 8 This is a schematic diagram of a multi-cavity box-section beam structure.

[0032] Figure 9 for Figure 8 AA sectional view. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0034] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0035] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] Example 1. A molding die for a high aspect ratio composite multi-cavity box-section structural beam, used in... Figures 1-9 The system includes a core assembly 1, the bottom and side walls of which are connected to a bottom support frame 2, a side support frame A3 and a side support frame B4, respectively. The core assembly 1 includes a base plate 5, a cavity core mold assembly 6 on the upper surface of the base plate 5, a beam core mold assembly 7 on the upper surface of the cavity core mold assembly 6, and side mold assemblies A8 and B9 on both sides of the cavity core mold assembly 6, which can be laterally aligned. After the side mold assemblies A and B are aligned, they can surround the cavity core mold assembly 6, and the slot 10 formed at the top after alignment can limit the beam core mold assembly 7. After the side mold assemblies A and B are aligned, the top is covered with a top cover 11.

[0037] The aforementioned cavity core mold assembly 6 includes a group of one or more core units arranged along the length direction of the substrate 5. The core unit includes a central block 61. The two sides of the central block 61 are connected by a mortise and tenon structure with side inserts A62 and side inserts B63. The mortise and tenon structure can ensure that the central block 61 can be pulled out from the bottom between the two inserts.

[0038] The aforementioned center block 61 has a draft angle on the side wall that contacts the side insert.

[0039] The core units located at both ends and the middle of substrate 5 are elastic cores (made of foam). Rigid foam is used to replace the metal modules in the middle section and on both sides of the box segment to create a buffer structure and eliminate the effects of thermal expansion during the heating process of the mold.

[0040] The aforementioned beam core mold assembly 7 includes a group of one or more beam core units arranged along the length direction of the substrate 5. The beam core unit includes a pair of beam core inserts A71 and B72 that are laterally mated. The mating surfaces of beam core inserts A and B are inclined to facilitate demolding.

[0041] The top surfaces of the aforementioned beam core inserts A and B are respectively provided with locking modules A73 and B74. After locking modules A and B are aligned, they cooperate with the locking groove provided on the bottom surface of the top cover 11.

[0042] Both of the aforementioned side mold components A and B are frame beam structures. This frame structure achieves the dual effect of weight reduction and increased mold rigidity.

[0043] The forming method of the aforementioned high aspect ratio composite multi-cavity box segment structure beam forming mold includes the following steps:

[0044] S1. Connect the center block 61, side inlay block A62 and side inlay block B63 with mortise and tenon structure to form core unit, and then lay the ribs 121 of the multi-cavity box segment structural beam 12 on the end face of the core unit.

[0045] S2. Install each core unit that has been laid out onto the substrate 5 in sequence to form the cavity core mold assembly 6; lay the lower frame main beam 122 of the multi-cavity box segment structural beam 12 on the top surface of the cavity core mold assembly 6;

[0046] S3. Vacuum pre-compact the laid ribs 121 and the lower frame main beam 122; the pre-compacting process is as follows: use sealing adhesive tape, vacuum bags and breathable felt to vacuum seal the assembled substrate 5 and cavity core mold assembly 6, with a vacuum degree of not less than 0.08Mpa; put the sealed mold into the oven to start pre-compacting, and the pre-compacting process parameters are: (60~100)℃×(30~60)min;

[0047] S4. Assemble beam core blocks A and B to form beam core units, splice each beam core unit to form beam core module assembly 7, and lay the upper frame main beam 123 of multi-cavity box segment structure beam 12 on beam core module assembly 7.

[0048] S5. Position and place the completed upper frame main beam 123 together with the beam core mold assembly 7 on the top surface of the upper frame main beam 123;

[0049] S6. Lay the skin A124 and skin B125 of the multi-cavity box segment structural beam 12 on the inner surfaces of the side mold components A and B respectively; after laying, the side mold components A and B are aligned so that the slot 10 can lock the beam core mold component 7 from the side and fix it on the base plate 5.

[0050] S7. Snap the top cover 11 onto the top surface of the side mold components A and B after they are aligned, and make the locking groove cooperate with the aligned locking modules A and B to complete the assembly of the mold core component 1; after completion, install the bottom support frame 2, the side support frame A3 and the side support frame B4 around the mold core component 1.

[0051] S8. Inject resin into mold core assembly 1 for liquid molding. Resin injection: Set the oven ambient temperature to no higher than 90℃, turn on the blower and heating, and when the mold temperature is 75±5℃, maintain the temperature for no less than 1 hour before performing the resin injection process. When the mold temperature is in the range of 60℃~80℃, place the resin into the injection tank, and degas it under vacuum. During degassing, the vacuum degree should be greater than 0.08Mpa, and the degassing time should be at least 30 minutes. After the resin degassing is completed, remove the vacuum from the resin tank. Under natural conditions, resin injection takes about 5 to 10 minutes; turn on compressed air, maintain the air pressure at 0.05Mpa, open the valve, and inject. After all the outlets are closed, close all valves and hold the resin for no less than 5 minutes; increase the pressure to 0.1Mpa, open the valve, and inject. After all the outlets of the mold have discharged resin, close all valves, hold the resin for 5 minutes, and repeat the cycle 1 to 3 times; increase the pressure to 0.15Mpa, open the valve, and inject. After all the mold outlets have dispensed glue, close all valves and allow the glue to hold for at least 5 minutes, repeating this cycle 1-3 times. Increase the pressure to 0.2 MPa, then open the valves and inject. (This process is repeated 1-3 times.) After injection, close all outlets; remove the injection tank from the oven and clean it promptly.

[0052] S9. After resin injection, start heating. When the mold temperature reaches (160±5)℃, keep it at that temperature for (1~1.5)h. Continue heating. When the mold temperature reaches (185±5)℃, keep it at that temperature for (3~6)h. After the heat preservation is completed, start cooling. When the mold temperature drops to ≤60℃, the curing is complete.

[0053] S10. When the mold temperature drops below 60℃, remove the mold from the oven, remove the bottom support frame 2, and remove the top cover 11 and the base plate 5;

[0054] S11. Take out the beam core block assembly and the cavity core block assembly in the following order: beam core block B72, beam core block A71, center block 61, side block A62 and side block B63.

[0055] S12. Disassemble side support frame A3, side support frame B4, side mold assembly A8 and side mold assembly B9;

[0056] S13. Remove the part, mark the part as finished, and clean the mold at the same time.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A molding die for a multi-cavity box-section beam structure made of composite materials with a high aspect ratio, characterized in that, The system includes a core assembly (1), the bottom and side walls of which are connected to a bottom support frame (2), a side support frame A (3) and a side support frame B (4) respectively; the core assembly (1) includes a base plate (5), a cavity core mold assembly (6) is provided on the upper surface of the base plate (5), a beam core mold assembly (7) is provided on the upper surface of the cavity core mold assembly (6), and side mold assemblies A (8) and B (9) are provided on both sides of the cavity core mold assembly (6) respectively, which can be aligned laterally. After the side mold assemblies A and B are aligned, they can surround the cavity core mold assembly (6) and align. The slot (10) formed at the top can limit the beam core mold assembly (7); after the side mold assemblies A and B are assembled, the top is covered with a top cover (11); the cavity core mold assembly (6) includes a group of more than one core unit arranged along the length direction of the substrate (5), the core unit includes a central block (61), and the two sides of the central block (61) are connected by a tenon and mortise structure with side inserts A (62) and side inserts B (63), the tenon and mortise structure can ensure that the central block (61) can be pulled out from the bottom between the two inserts; the core units located at both ends and the middle of the substrate (5) are elastic cores.

2. The high aspect ratio composite multi-cavity box-section structural beam forming mold according to claim 1, characterized in that, The sidewalls of the center block (61) that contact the side inserts are designed with draft angles.

3. The high aspect ratio composite multi-cavity box-section structural beam forming mold according to claim 1, characterized in that, The beam core module assembly (7) includes a group of one or more beam core units arranged along the length direction of the substrate (5). The beam core unit includes a pair of beam core inserts A (71) and B (72) that are aligned laterally. The mating surfaces of beam core inserts A and B are inclined.

4. The high aspect ratio composite multi-cavity box-section structural beam forming mold according to claim 3, characterized in that, The top surfaces of the beam core inserts A and B are respectively provided with locking module A (73) and locking module B (74). After locking modules A and B are engaged, they cooperate with the locking groove set on the bottom surface of the top cover (11).

5. The molding die for a high aspect ratio composite multi-cavity box-section structure beam according to claim 1, characterized in that, Both the side mold components A and B are frame beam structures.

6. A molding method for a high aspect ratio composite multi-cavity box-section structural beam forming mold as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Connect the center block (61), side inlay block A (62) and side inlay block B (63) with mortise and tenon structure to form a core unit, and then lay the ribs (121) of the multi-cavity box segment structure beam (12) on the end face of the core unit; S2. Install the core units that have been laid out onto the substrate (5) in sequence to form a cavity core mold assembly (6); lay the lower frame main beam (122) of the multi-cavity box segment structure beam (12) on the top surface of the cavity core mold assembly (6); S3. Vacuum pre-compact the laid ribs (121) and the lower frame main beam (122); S4. Pair the beam core inserts A and B to form a beam core unit, splice the beam core units to form a beam core module assembly (7), and lay the upper frame main beam (123) of the multi-cavity box segment structure beam (12) on the beam core module assembly (7); S5. Position the completed upper frame main beam (123) together with the beam core mold assembly (7) on the top surface of the upper frame main beam (123); S6. Lay the skin A (124) and skin B (125) of the multi-cavity box segment structural beam (12) on the inner surfaces of the side mold components A and B respectively; after laying, the side mold components A and B are aligned so that the slot (10) clamps the beam core mold component (7) from the side and fixes it on the base plate (5). S7. Attach the top cover (11) to the top surface of the side mold components A and B after they are aligned, and make the locking groove cooperate with the aligned locking modules A and B to complete the assembly of the mold core component (1); after completion, install the bottom support frame (2), side support frame A (3) and side support frame B (4) around the mold core component (1). S8. Inject resin into the mold core assembly (1) for liquid molding.

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