Compression molding tool and molding method for composite material trailing edge strip

Abstract

The invention belongs to the technical field of mold auxiliary equipment, and relates to a composite material rear edge strip compression molding tool and a molding method. The composite material rear edge strip compression molding tool comprises an upper die and a lower die, a cavity is formed in the lower die and extends in the length direction of the lower die, and the section of the cavity is consistent with the structure of a composite material rear edge strip; the upper die is arranged above the lower die and used for forming the upper surface of the composite material trailing edge strip. The tool has the advantages that the tool manufacturing period is shortened as long as the stop blocks are arranged at the head end and the tail end; the problem of flash caused by flowing of resin of the upper die is eliminated, and the part is high in overall appearance manufacturing precision and good in surface quality; the labor intensity of workers and the manufacturing cost are greatly reduced, and the production cycle of products is shortened; the problems of debonding, skin layering and cracking possibly occurring after parts are assembled on airfoil products can be effectively solved, and the flight safety is effectively guaranteed; the die is durable and not prone to deformation, and the follow-up maintenance cost of the tool is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of mold auxiliary equipment, and relates to a die pressing forming tooling and a forming method for a composite trailing edge strip. Background Art

[0002] Composite trailing edge strips are generally applied to composite wing surface products, which play the roles of supporting the skin, maintaining the shape of the trailing edge of the wing surface, and transmitting the aerodynamic force received by the trailing edge of the skin to the wing beam and wing rib.

[0003] Generally, the structure of the die pressing forming tooling for composite trailing edge strips adopts the form of upper and lower die clamping. The die clamping surface of the upper and lower dies is set on the demarcation line of the upper and lower wing surfaces of the trailing edge strip, as Figure 1 shown. The working principle of the tooling: First, prepreg is filled in the cavities of the upper die and the lower die respectively. After the prepreg is filled to be basically flush with the die clamping surface, the upper and lower dies are clamped together and placed in a press for heating and curing to form.

[0004] This kind of tooling structure has the following deficiencies: 1. During the forming process of the trailing edge strip, after the prepreg in the upper die is heated, the resin flows. Under the action of gravity, the resin often carries a part of the composite material fibers and flows into the die clamping seam, resulting in that the tooling often cannot be completely clamped, and a large amount of flash is generated on the die clamping surface after forming. At the same time, the overall shape of the trailing edge strip will be too thick, and the surface quality of the upper wing surface is poor, with a large number of pits; 2. The flash on the die clamping surface, the too thick part shape of the part and the surface pits lead to the need for manual processing and repair by workers. For the processing and repair of composites, the labor intensity of workers is large and the efficiency is low; 3. After the processed trailing edge strip is formed, it cannot be inspected by returning to the die, and the consistency of the product shape cannot be guaranteed. After being assembled with the skin, beam, spar, rib, etc. by adhesive bonding to form a wing surface product, it is easy to cause the skin at the trailing edge of the wing surface to be debonded from the trailing edge strip, local delamination of the trailing edge of the skin, and even cracking, which will seriously affect flight safety; 4. After the long-term use of the die, the upper die is prone to deformation, resulting in the scrapping of the die. Summary of the Invention

[0005] The purpose of the present invention is to provide a die pressing forming tooling for a composite trailing edge strip, so as to achieve the purposes of improving the overall shape consistency of the part, shortening the processing time of workers, reducing the production cost, ensuring the part accuracy, and preventing the subsequent wing surface products from being debonded, the skin from delaminating, and cracking.

[0006] To achieve the above purpose, the present invention adopts the following technical solution: A die pressing forming tooling for a composite trailing edge strip, including an upper die and a lower die. A cavity is arranged in the lower die, and the cavity extends along the length direction of the lower die, and its cross section is consistent with the structure of the composite trailing edge strip; the upper die is placed above the lower die and is used for forming the upper surface of the composite trailing edge strip.

[0007] Further, the tooling further includes detachable stoppers. The number of the stoppers is two, and they are respectively placed at the head and the tail of the length direction of the tooling, and are located between the upper die and the lower die.

[0008] Preferably, the cross section of the stopper is L-shaped, one end of which is flush with the edge of the end of the upper die and the lower die, and the other end is flush with the edge of the end of the cavity.

[0009] Preferably, a notch is provided on the stopper to facilitate the detachment of the stopper along the length direction of the tooling.

[0010] Preferably, the mating surface of the upper die and the lower die is a stepped surface.

[0011] Another object of the present invention is to provide a method for forming a composite trailing edge strip, which uses the above-mentioned compression molding tooling, and includes the following steps: 1) Optimize the mold structure, cancel the cavity of the upper die, and set all the cavities in the lower die; cancel the middle stoppers, and only retain the stoppers at the head and the tail; 2) Lay the composite trailing edge strip to be formed in the lower die, that is, place it obliquely in the lower die, and lay the upper surface of the composite trailing edge strip to be formed until it is flush with the mating surface, so that its upper surface is smoothly transitioned with the mating surface, and cover the upper die above the lower die; 3) Press the compression molding tooling on a hot press for compression molding; 4) After the composite trailing edge strip to be formed is formed, first lift the upper die of the compression molding tooling, then remove the detachable stoppers at both ends, and then take out the composite trailing edge strip from the mold.

[0012] When it is necessary to check by returning to the mold, it is not necessary to close the upper die. As long as the part is placed in the lower die and check whether the upper surface is flush with the mating surface.

[0013] Compared with the prior art, the present invention has the following advantages: 1. The mold does not need to process the cavity on the upper die, and does not need to be provided with stoppers along the entire length direction. As long as stoppers are provided at the head and the tail, the manufacturing cycle of the tooling is shortened; 2. The flash problem caused by the resin flow of the upper die is eliminated, the overall shape manufacturing accuracy of the part is high, and the surface quality is good; 3. The labor intensity of workers and the manufacturing cost are greatly reduced, and the product production cycle is shortened; 4. It can effectively avoid the problems of debonding, skin delamination, and cracking that may occur after the part is assembled to the wing surface product, effectively ensuring flight safety; 5. The mold is durable and not easy to deform, reducing the subsequent maintenance cost of the tooling. Description of the Drawings

[0014] Figure 1Schematic structural diagram of the background art of the present invention Figure 2 is Figure 1 the A-A sectional view of; Figure 3 Schematic structural diagram of the embodiment of the present invention; Figure 4 is this Figure 3 the A-A sectional view of; Figure 1-2 In, 1-upper mold; 2-lower mold; 3-stop block; 4-trailing edge strip; Figure 3-4 In, 1-upper mold; 2-lower mold; 3-stop block; 4-trailing edge strip. Specific implementation mode

[0015] The following combines the attached Figure 3-4 Further details of the present invention are described below: A composite trailing edge strip molding tooling includes an upper mold 1 and a lower mold 2. The cavity of the upper mold 1 is cancelled, and a cavity is arranged in the lower mold 2. The cavity extends along the length direction of the lower mold, and its cross-section is consistent with the structure of the composite trailing edge strip 4; The upper mold 1 and the lower mold 2 are connected through the positioning pins of the lower mold. The upper mold 1 is placed above the lower mold 2 and is used to form the upper surface of the composite trailing edge strip 4.

[0016] As a preferred implementation mode of the present invention, the tooling further includes a detachable stop block 3. The number of stop blocks is two, which are respectively placed at the head and tail ends of the length direction of the tooling and are located between the upper mold 1 and the lower mold 2. In this embodiment, the stop block 3 is a metal stop block. The cross-section of the stop block 3 is L-shaped. One end of it is flush with the end edges of the upper mold 1 and the lower mold 2, and the other end is flush with the end edge of the cavity; After the upper mold and the metal stop blocks at both ends are disassembled, the side of the trailing edge strip 4 is exposed, and the trailing edge strip part can be taken out from the lower mold 2.

[0017] To facilitate the disassembly and removal of the stop block 3 along the length direction of the tooling, a notch is provided on the stop block 3.

[0018] As a preferred implementation mode of the present invention, the mating surface of the upper mold 1 and the lower mold 2 is a stepped surface.

[0019] A forming method for a composite trailing edge strip uses the molding tooling as described above and includes the following steps: 1) Cancel the cavity of the upper mold 1 and set all the cavities in the lower mold 2; 2) Lay the part in the lower mold 2, and lay the upper surface of the part (trailing edge strip) flush with the mating surface; 3) Perform compression molding on the hot press of the molding tooling; 4) After the part is formed, remove the detachable stop blocks 3 at both ends of the molding tooling and take out the part; 5) When mold inspection is required later, there is no need to close the mold with the upper mold 1. Just place the part in the lower mold 2 and check whether the upper surface is flush with the mold closing surface.

Claims

1. A composite material trailing edge molding tool, comprising an upper mold and a lower mold, characterized in that: A cavity is arranged in the lower mold, which extends along the length direction of the lower mold and has a cross section consistent with the structure of the composite material trailing edge strip; the upper mold is placed above the lower mold and is used to shape the upper surface of the composite material trailing edge strip.

2. The composite material trailing edge molding tool according to claim 1, characterized in that: The tooling also includes two detachable stoppers, which are respectively disposed at the head and tail ends of the tooling in the length direction and between the upper die and the lower die.

3. The composite material trailing edge molding tool according to claim 2, characterized in that: The cross section of the stopper is L-shaped, one end of which is flush with the edge of the upper die and the lower die, and the other end is flush with the edge of the cavity.

4. The composite material trailing edge molding tool according to claim 2, characterized in that: A notch is provided on the stopper to facilitate disassembly of the stopper along the length direction of the tooling.

5. The composite material trailing edge molding tool according to claim 1, characterized in that: The mating surface between the upper die and the lower die is a stepped surface.

6. A composite material trailing edge strip forming method, characterized in that: The compression molding tool as claimed in any one of claims 1 to 5 comprises the following steps: 1) Cancel the cavity of the upper mold and set all the cavities in the lower mold; 2) The rear edge strip of the composite material to be formed is laid in the lower mold, and the upper surface of the rear edge strip of the composite material to be formed is laid until it is flush with the mold surface; 3) Place the molding tool on a hot press for molding; 4) After the rear edge strip of the composite material is formed, first lift the upper die of the compression molding tooling, then remove the removable stoppers at both ends, and finally remove the rear edge strip of the composite material from the mold.

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