A method of forming a vertical tail wing tip shroud

Abstract

The application discloses a forming method of a vertical tail wing tip cover, and comprises the following steps: S1, preparing prepreg; S2, preparing a male mold and a female mold; S3, according to the layering sequence, the prepreg sheet is pasted to the outer mold, and the layer is rolled to be flat; S4, the prepreg sheet on the outer mold is peeled off as a whole and placed in the female mold, the rolling plate is used to roll and press the air area, the vacuum bag is prepared outside the mold, the vacuum bag is vacuumized at normal temperature, and the vacuum bag is removed after a set time threshold is reached; S5, if the number of layers pasted on the outer mold reaches a set layering number threshold, the step S6 is turned to, otherwise, the step S3 is turned to; S6, according to the layering sequence, 5 layers of prepreg are pasted on the upper part of the inner side of the prepreg in the female mold, the rolling plate is used for rolling and pressing, and vacuumization is carried out; S7, the pre-compacted insert block is placed at the wing tip of the wing tip cover, encapsulated, and sent into the autoclave for curing; and the vertical tail wing tip cover with low weight can be reliably prepared by using the application.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, and in particular to a molding method for a vertical tail fin tip cover. Background Technology

[0002] A vertical tail fin tip dome is a special device installed at the tip of an aircraft's vertical tail, primarily used to improve the aircraft's aerodynamic performance, while also housing various electronic devices and antennas. Currently, the vertical tail fin tip domes used in large aircraft are mainly all-metal structures, which are excessively heavy. To address the aforementioned issues, this application proposes a method for molding a vertical tail fin tip dome using composite materials in an autoclave. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] In view of the problems existing in the above and / or existing vertical tail fin tip manufacturing processes, the present invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a molding method for a vertical tail fin tip cover. This invention uses composite materials to reliably manufacture the vertical tail fin tip cover, greatly reducing the product weight.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for forming a vertical tail fin tip canopy, comprising the following steps:

[0007] S1. Prepare the prepreg material;

[0008] S2. Prepare a male mold and a female mold. The male mold includes a fixed base, and an outer paving mold is fixedly connected to the upper side of the fixed base. The female mold includes a first mold body and a second mold body that are detachably connected together. The first mold body has a first paving opening on the side opposite to the second mold body, and the second mold body has a second paving opening on the side opposite to the first mold body. The first paving opening and the second paving opening form a paving groove. The shape of the outer edge of the paving groove is the same as the shape of the outer edge of the outer paving mold.

[0009] S3. Following the layering sequence, lay the prepreg sheets onto the outer laying mold, and roll them out firmly after each layer is laid.

[0010] S4. Peel off the material sheet from the outer cover mold and place it into the first mold body and the second mold body. Use a rolling pin to roll and press the suspended area. Attach a vacuum bag to the outside of the mold. Vacuum the vacuum bag at room temperature. After the set time threshold is reached, remove the vacuum bag.

[0011] S5. If the number of layers on the outer tiling mold reaches the set threshold number of layers, proceed to step S6; otherwise, proceed to step S3.

[0012] S6. Lay 5 layers of prepreg in the upper part of the inner side of the prepreg in the female mold according to the layup order, roll it out with a rolling board, paste a vacuum bag on the outside of the mold, vacuum the vacuum bag at room temperature, and use the vacuum pressure to flatten the material sheet to form the wingtip cover forming mold.

[0013] S7. Place the pre-compacted insert into the wingtip of the wingtip cover, seal it, and send it into an autoclave for curing.

[0014] S8. Remove the cured product from the female mold. After the product has been cured, leave some allowance at the edge. Use a cutting machine to cut off the allowance according to the cutting line on the product to obtain the vertical tail wingtip cover.

[0015] As a further improvement of the present invention, in step S7, the step of preparing the insert is to lay 110 layers of prepreg in the lower mold of the insert forming mold according to the set lay-up sequence, and compact it once every 8 layers. After the lay-up is completed, the upper mold of the insert forming mold is fixedly connected to the upper side of the lower mold, and the upper press is used for compaction.

[0016] As a further improvement of the present invention, when the upper press is used for pressing, the initial pressure is 8MPa±0.1MPa, and the mold is heated to 60℃±5℃ at a heating rate of no more than 1.5℃ / min. Under this condition, the mold is kept at the temperature and pressure for 0.5h±10min.

[0017] As a further improvement of the present invention, in S3, the layering process is as follows: first, a layer of release fabric is laid on the outer laying mold, the seams are joined together, and vacuum is applied to compact it; the prepreg is laid from the center of the mold to the surrounding margin area, and the prepreg is smoothed by hand along the curved surface of the mold from the center to the surrounding area, with the splicing gap or overlap width not exceeding 1mm; after each layer is laid, it is checked whether it is rolled out; if the fibers are found to jump when rolling with a rolling pin, it indicates that there is bridging, and the layer needs to be peeled off and re-laid.

[0018] As a further improvement of the present invention, in step S6, the laying process is as follows: the material sheet is a rectangular strip with a total of 5 layers and the laying angle is [45 / 0 / 45 / 0 / 45]. When laying, the edge of the material sheet along the length direction is aligned with the allowance line on the mold. Since the opening of the solid area of ​​the mold is small, it is not possible to smooth it by hand. A rolling board is needed to roll the material sheet to fit the mold.

[0019] As a further improvement of the present invention, in step S7, the curing process is as follows: Vacuuming is performed at room temperature with a vacuum degree of not less than 0.092 MPa. After passing a cold pressure test, the thermocouple is placed in a curing tank, and the entire process is kept under vacuum. Temperature is increased at room temperature at a rate ≤2.0℃ / min. Pressure is applied at room temperature at a rate of 0.02 MPa / min to 0.6 MPa. The medium temperature is set to 135℃, and when the slowest thermocouple reaches 125℃, it is held for 60-70 minutes. The medium temperature is set to 190℃, and when the slowest thermocouple reaches 180℃, it is held for 120-130 minutes. The temperature is then reduced to below 70℃ at a rate not exceeding 2.5℃ / min, and the pressure is released. When the temperature of the fastest cooling thermocouple drops below 60℃, the tank can be opened.

[0020] Compared with the prior art, the present invention has the following technical effects: the vertical tail wingtip is a laminated plate structure with an overall thickness of 1mm. The wingtip is filled with wedge-shaped inserts to form a solid area. The present application can produce a wingtip dome made of composite material with a very thin tip, which reduces the structural weight and increases the space for the aircraft's payload. It can be applied to the preparation of vertical tail wingtip domes. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0022] Figure 1 This is a three-dimensional structural diagram of the male mold in this invention.

[0023] Figure 2 This is a three-dimensional structural diagram of the female mold in this invention.

[0024] Figure 3 This is a three-dimensional structural diagram of the lower mold in the insert molding die.

[0025] Figure 4 This is a three-dimensional structural diagram of the upper mold in the insert molding die.

[0026] Figure 5 This is a three-dimensional structural diagram of the insert molding mold in this invention.

[0027] Figure 6 This is a three-dimensional structural diagram of the insert prepared using the present invention.

[0028] Figure 7 This is a three-dimensional structural diagram of the vertical tail fin tip canopy prepared using the present invention.

[0029] In the diagram: 100 Male mold, 101 Fixed base, 102 Outer paving mold; 200 Female mold, 201 First mold body, 201-1 First paving opening, 202 Second mold body, 202-1 Second paving opening, 300 Inlay forming mold, 301 Lower mold, 301-1 Inlay paving groove, 302 Upper mold, 302-1 Pressing groove, 400 Inlay, 500 Vertical tail wingtip cover, 501 Reinforcing layer, 502 Solid area. Detailed Implementation

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0033] Reference Figures 1-7 This embodiment provides a method for molding a vertical tail fin tip, which can reliably produce a vertical tail fin tip with composite material.

[0034] A method for forming a vertical tail fin tip canopy includes the following steps:

[0035] S1. Prepare the prepreg. Use the CPD module of Catia software to simulate the shape of each layer of prepreg and import it into the operating system of the automatic feeder. Before preparation, take the prepreg out of the cold storage 6 hours in advance to thaw it. Let it stand at room temperature until there is no moisture in the packaging bag. Place the thawed prepreg on the tray of the automatic feeder and cut each piece of material according to the program.

[0036] S2. Prepare the male mold, female mold, and insert molding mold. The male mold includes a fixed base, with an outer cover mold fixedly connected to the upper side of the fixed base. The shape of the outer cover mold is the same as the outer edge of the vertical tail wing tip. The female mold includes a first mold body and a second mold body that are detachably connected together. The first mold body has a first cover opening on the side opposite to the second mold body, and the second mold body has a second cover opening on the side opposite to the first mold body. The first and second cover openings form a cover groove, and the shape of the outer edge of the cover groove is the same as the outer edge of the outer cover mold. The insert molding mold includes a lower mold and an upper mold. The lower mold has an upward-facing insert cover groove, and the lower end of the upper mold has a groove with the same shape as the upper outer edge of the insert. The mold is then processed as follows: after degreasing the mold, use a soft tool to remove residual resin and other debris from the working surface of the mold, and use mold cleaning paper dipped in acetone to clean the working surface of the mold. Apply three coats of release agent to the surfaces of the upper and lower molds, ensuring no areas are missed, with a 15-minute interval between each coat.

[0037] S3. Following the layup sequence, lay the prepreg sheets onto the outer layup mold. Each layer of prepreg sheet should be 0.2mm thick. After laying one layer, roll it out firmly.

[0038] S4. Peel off the material sheet from the outer cover mold and place it into the first mold body and the second mold body. Use a rolling pin to roll and press the suspended area. Attach a vacuum bag to the outside of the mold. Vacuum the vacuum bag at room temperature. After the set time threshold is reached, remove the vacuum bag.

[0039] S5. If the number of layers on the outer tiling mold reaches the set tiling layer threshold, in this embodiment, the tiling layer threshold is 5, then proceed to step S6; otherwise, proceed to step S3.

[0040] S6. Lay 5 layers of prepreg in the upper part of the inner side of the prepreg in the female mold according to the layup order, roll it out with a rolling board, paste a vacuum bag on the outside of the mold, vacuum the vacuum bag at room temperature, and use the vacuum pressure to flatten the material sheet to form the wingtip cover forming mold.

[0041] S7. Place the pre-compacted insert into the wingtip of the wingtip cover, seal it, and send it to an autoclave for curing. The curing process is as follows: evacuate at room temperature with a vacuum degree of not less than 0.092 MPa, pass the cold pressure test, and then proceed to the autoclave for curing, maintaining a vacuum throughout the process; heat up at room temperature at a rate ≤2.0℃ / min; pressurize at room temperature at a rate of 0.02 MPa / min to 0.6 MPa; set the medium temperature to 135℃, and hold the slowest thermocouple at 125℃ for 60-70 minutes; set the medium temperature to 190℃, and hold the slowest thermocouple at 180℃ for 120-130 minutes; cool down to below 70℃ at a rate not exceeding 2.5℃ / min, then release the pressure; when the fastest cooling thermocouple reaches below 60℃, the autoclave can be opened.

[0042] S8. Remove the cured product from the female mold. After the product has been cured, leave some allowance at the edge. Use a cutting machine to cut off the allowance according to the cutting line on the product to obtain the vertical tail wingtip cover.

[0043] In S3, the layup process is as follows: First, lay a layer of release fabric on the outer layup mold, align the seams, and vacuum-press it. Then, lay the prepreg from the center of the mold to the surrounding margin area, and smooth it with your hand along the curved surface of the mold from the center to the surrounding area. The gap or overlap width should not exceed 1mm. After each layer is laid, check whether it is rolled out. If the fibers are found to jump when rolling with a rolling pin, it indicates that there is bridging, and the layer needs to be peeled off and re-laid.

[0044] In step S6, the laying process is as follows: the material sheet is a rectangular strip with a total of 5 layers and the laying angle is [45 / 0 / 45 / 0 / 45]. When laying, align the edge of the material sheet along the length direction with the allowance line on the mold. Since the opening of the solid area of ​​the mold is small, it is not possible to smooth it by hand. A rolling board is needed to roll the material sheet to fit the mold.

[0045] In step S7, the steps for preparing the insert are as follows: according to the set layup sequence, 110 layers of prepreg are laid in the lower mold of the insert molding mold, and compacted once every 8 layers are laid. After the laying is completed, the upper mold of the insert molding mold is fixedly connected to the upper side of the lower mold; the upper press is used for compaction, with an initial pressure of 8MPa±0.1MPa, and the mold is heated to 60℃±5℃ at a heating rate of no more than 1.5℃ / min, and kept at this temperature and pressure for 0.5h±10min.

[0046] This invention first uses a positive mold to lay out the overall outline of the wingtip fairing, then places the rolled-out overall outline into a negative mold, repeating this process five times. After this, the wingtip area within the negative mold has space for direct laying. After compaction, five layers of prepreg are laid on the upper inner edge of the wingtip fairing as a reinforcing layer. Inserts are then inserted at the wingtip positions to form a solid area. After encapsulation and curing, the vertical tail wingtip fairing (e.g., ...) is completed. Figure 7 As shown,Figure 7 The holes on the top are completed by subsequent machining, which is existing technology and not an improvement of this invention. The preparation of the holes solves the technical problem that composite materials cannot be used to prepare aircraft parts with extremely fine conical tips. The surface of the vertical tail tip dome prepared using this invention is smooth and flat, and there are no problems with non-destructive testing.

[0047] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for forming a vertical tail fin tip diffuser, characterized in that: Includes the following steps, S1. Prepare the prepreg material; S2. Prepare a male mold and a female mold. The male mold includes a fixed base, and an outer paving mold is fixedly connected to the upper side of the fixed base. The female mold includes a first mold body and a second mold body that are detachably connected together. The first mold body has a first paving opening on the side opposite to the second mold body, and the second mold body has a second paving opening on the side opposite to the first mold body. The first paving opening and the second paving opening form a paving groove. The shape of the outer edge of the paving groove is the same as the shape of the outer edge of the outer paving mold. S3. Following the layering sequence, lay the prepreg sheets onto the outer laying mold, and roll them out firmly after each layer is laid. S4. Peel off the material sheet from the outer cover mold and place it into the first mold body and the second mold body. Use a rolling pin to roll and press the suspended area. Attach a vacuum bag to the outside of the mold. Vacuum the vacuum bag at room temperature. After the set time threshold is reached, remove the vacuum bag. S5. If the number of layers on the outer tiling mold reaches the set threshold number of layers, proceed to step S6; otherwise, proceed to step S3. S6. Lay 5 layers of prepreg in the upper part of the inner side of the prepreg in the female mold according to the layup order, roll it out with a rolling board, paste a vacuum bag on the outside of the mold, vacuum the vacuum bag at room temperature, and use the vacuum pressure to flatten the material sheet to form the wingtip cover forming mold. S7. Place the pre-compacted insert into the wingtip of the wingtip cover, seal it, and send it into an autoclave for curing. S8. Remove the cured product from the female mold. After the product has been cured, leave some allowance at the edge. Use a cutting machine to cut off the allowance according to the cutting line on the product to obtain the vertical tail wingtip cover.

2. The method for forming the vertical tail fin tip diffuser as described in claim 1, characterized in that: In step S7, the step of preparing the insert is to lay 110 layers of prepreg in the lower mold of the insert forming mold according to the set lay-up sequence, and compact it once every 8 layers. After laying, the upper mold of the insert forming mold is fixedly connected to the upper side of the lower mold, and the upper press is used for compaction.

3. The method for forming the vertical tail fin tip canopy as described in claim 2, characterized in that: When pressing the mold, the initial pressure is 8MPa±0.1MPa. The mold is heated to 60℃±5℃ at a heating rate of no more than 1.5℃ / min. Under these conditions, the mold is kept at the same temperature and pressure for 0.5h±10min.

4. The method for forming the vertical tail fin tip canopy as described in claim 1, characterized in that: In S3, the layering process is as follows: first, a layer of release fabric is laid on the outer laying mold, the seams are joined together, and vacuum is applied to compact it; the prepreg is laid from the center of the mold to the surrounding margin area, and the prepreg is smoothed by hand along the curved surface of the mold from the center to the surrounding area, with the gap or overlap width not exceeding 1mm; after each layer is laid, it is checked whether it is rolled out; if the fibers are found to jump when rolling with a rolling board, it indicates that there is bridging, and the layer needs to be peeled off and re-laid.

5. The method for forming the vertical tail fin tip canopy as described in claim 1, characterized in that: In step S6, the laying process is as follows: the material sheet is a rectangular strip with a total of 5 layers and the laying angle is [45 / 0 / 45 / 0 / 45]. When laying, the edge of the material sheet along the length direction is aligned with the allowance line on the mold. Because the opening of the solid area of ​​the mold is small, it is not possible to smooth it by hand. A rolling board is needed to roll the material sheet to fit the mold.

6. The method for forming the vertical tail fin tip canopy as described in claim 1, characterized in that: In step S7, the curing process is as follows: Vacuum is applied at room temperature with a vacuum level of not less than 0.092 MPa. After passing a cold pressure test, the thermocouple is placed in the curing tank, maintaining a vacuum throughout the process. Temperature is increased at room temperature at a rate ≤2.0℃ / min. Pressure is applied at room temperature at a rate of 0.02 MPa / min to 0.6 MPa. The medium temperature is set to 135℃. When the slowest thermocouple reaches 125℃, it is held for 60-70 minutes. The medium temperature is then set to 190℃. When the slowest thermocouple reaches 180℃, it is held for 120-130 minutes. The temperature is then reduced to below 70℃ at a rate not exceeding 2.5℃ / min, and the pressure is released. The tank can be opened when the fastest-cooling thermocouple temperature drops below 60℃.

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