Vacuum auxiliary forming method for solving wrinkles of torsion large-thickness beam for aviation

Abstract

The invention discloses a vacuum auxiliary forming method for solving wrinkles of a torsion large-thickness beam for aviation, which comprises the following steps of: brushing resin, scattering shaping powder, paving material sheets and locking edges, performing hot compaction, arranging runners and packaging and curing, namely calculating the use amount of the shaping powder according to a coefficient of 3-6% to ensure that the scattering process is uniform and controllable, and fixing and locking the edges of the material sheets every a certain number of layers. Interlayer slippage of material sheets is slowed down, interlayer compaction of the whole part is ensured through medium and low temperature hot compaction and natural cooling treatment, and wrinkles can be conveniently observed and treated in time; the fiber layers of the part have high fitting degree, the cured part is good in appearance, free of wrinkles and high in internal quality, the whole operation process is simple and controllable, the cost is low, and the forming difficulty is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material forming, and in particular relates to a vacuum-assisted forming method for solving wrinkles of torsion thick-thickness beams used in aviation. Background Art

[0002] Vacuum-assisted molding technology is a composite molding technology that combines vacuum bags with traditional resin transfer molding technology. It has the characteristics of high performance and low cost. It has been widely used in fields such as automobile and shipbuilding. The vacuum-assisted molding process only requires one atmosphere of pressure when curing parts, and no additional pressure is required, which not only reduces the difficulty of operation, but also saves equipment investment. At the same time, since only a single-sided mold is required, the difficulty of mold manufacturing and mold investment are saved compared to the resin transfer molding process. Aviation parts need to maintain good physical and chemical properties in a high temperature environment. Therefore, advanced toughened epoxy resins are often used for high-temperature curing to form composite structural parts.

[0003] However, the thick torsional beam structure for aviation has complex curvature and large thickness. When the beam structure is formed at high temperature using the vacuum-assisted forming process, wrinkles or deformations are prone to occur. The thick beam stack is very difficult to form. Therefore, we propose a vacuum-assisted forming method to solve the wrinkles of thick torsional beams for aviation. Summary of the invention

[0004] The object of the present invention is to provide a vacuum-assisted forming method for solving the wrinkles of a torsionally thickened beam for aviation, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a vacuum-assisted forming method for solving the wrinkles of a torsion thick beam for aviation, comprising the following steps: A. Applying resin: At room temperature, evenly apply the high-grade toughened epoxy resin to the surface of a single-sided mold, lay a layer of sheet on the high-grade toughened epoxy resin, and use a pressure-sensitive tape to fix and lock the edge of the sheet; B. Sprinkle setting powder: Evenly sprinkle setting powder on the surface of the layer of sheet laid in step A; C. Paving and edge locking of the sheet: Continue to position and lay several layers of sheets using a laser projector, and evenly spread the shaping powder between each layer of sheets. Use pressure-sensitive tape to fix and lock the edges of the sheets every 1-3 layers of sheets. D. Hot compaction: An isolation film, a breathable felt and a vacuum bag are placed on the surface of the laid sheet in sequence for packaging, and then the whole is sent into an oven for hot compaction treatment. After the hot compaction treatment, it is naturally cooled, and the isolation film, breathable felt and vacuum bag are removed to obtain a semi-formed part of a torsion beam with large thickness for aviation, and the surface wrinkles of the semi-formed part of the torsion beam with large thickness for aviation are checked; E. Flow channel layout: When the surface of the semi-formed part of the aviation torsion thick beam is wrinkle-free, a layer of demoulding cloth, a layer of flow guide net and a plurality of glue injection pipes and glue outlet pipes are sequentially arranged on the surface of the semi-formed part of the aviation torsion thick beam; F. Packaging and curing: Finally, a vacuum bag is arranged on the surface of the semi-formed part of the aviation torsion thick beam, and vacuum leakage detection is carried out. After the vacuum leakage detection is completed, it is sent into an oven for curing and forming to obtain a finished product of the aviation torsion thick beam.

[0006] Preferably, in steps B and C, the calculation formula for the amount of shaping powder to be sprinkled on the surface of each layer of the sheet is as follows: m=ρsa Wherein, m represents the amount of setting powder to be spread; ρ represents the surface density of the sheet; s represents the surface area of ​​the sheet; a represents the uniform spreading coefficient of the setting powder, and a=3%-6%.

[0007] Preferably, in step C, the edges of different layers of material sheets are staggered.

[0008] Preferably, in step C, pressure-sensitive tapes are used to fix and lock the edges of the material sheets every 1-3 layers of the material sheets, and the pressure-sensitive tapes are staggered.

[0009] Preferably, in step D, the hot compaction temperature is 60-90° C. and the insulation time is 10-40 min.

[0010] Preferably, in step D, if wrinkles are found on the surface of the semi-formed part of the aviation torsion thick beam, a heat source below 60-90° C. is used to treat the wrinkles, and the specific process is as follows: Cover the surface of the semi-formed parts of the aviation torsion thick beam with wrinkles with a layer of isolation film, use a heat source below 60~90℃ to iron the surface of the isolation film and iron along the fiber direction until it is visually flat, then vacuum package and pre-compact once, the pre-compacting vacuum degree is ≥-90kpa, the time is ≥15min, repeat the above operation according to the wrinkle situation after pre-compacting until the wrinkles are eliminated.

[0011] Preferably, in step E, 1 to 3 glue injection pipes and 3 glue outlet pipes are provided.

[0012] Preferably, in step F, the leak detection vacuum is -70 to -95 kPa, and the leak detection time is 5 to 10 min.

[0013] Preferably, in step F, the curing temperature is 150-185° C. and the holding time is 2-3 hours.

[0014] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, the amount of shaping powder is calculated according to a coefficient of 3%-6% so that the spreading process is uniform and controllable, the edges of the sheet are fixed and locked at intervals of a certain number of layers to slow down the slippage between the sheets, and the hot compaction and natural cooling treatment at medium and low temperatures are performed to ensure the interlayer compaction of the entire part, which is convenient for observing wrinkles and processing them in time; the fiber layers of the part have a high degree of fit, the cured part has a good appearance, is wrinkle-free, and has high internal quality, the entire operation process is simple and controllable, the cost is low, and the molding difficulty is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of vacuum-assisted forming of a torsion heavy-thickness beam for aviation use according to the present invention.

[0016] In the figure: 1. Single-sided mold; 2. Advanced toughened epoxy resin; 3. Sheet; 4. Pressure-sensitive tape; 5. Setting powder; 6. Release cloth; 7. Guide net; 8. Glue injection hose; 9. Glue outlet hose; 10. Vacuum bag. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1 The vacuum-assisted forming method for solving the wrinkles of the torsion thick beam for aviation provided by the present invention comprises the following steps: A. Applying resin: At room temperature, the high-grade toughened epoxy resin 2 is evenly applied to the surface of the single-sided mold 1, so that the surface of the single-sided mold 1 has a certain viscosity, which is convenient for laying the first layer of the sheet and preventing the first layer of the sheet from slipping after contacting the single-sided mold. A layer of sheet 3 is laid on the high-grade toughened epoxy resin 2, and the edge of the sheet 3 is fixed with a pressure-sensitive tape 4; B. Sprinkle setting powder: Evenly sprinkle the shaping powder 5 on the surface of the layer of sheet 3 laid in step A; C. Paving and edge locking of the sheet: Continue to position and lay several layers of sheet 3 by using a laser projector. The edges of different layers of sheet 3 are staggered to increase edge friction and avoid wrinkles caused by resin scouring. Sprinkle shaping powder evenly between each layer of sheet 3. Use pressure-sensitive tape 4 to fix and lock the edges of sheet 3 every 1-3 layers of sheet 3. The pressure-sensitive tape 4 is staggered. The staggered edges of different layers of sheet 3 determine that the pressure-sensitive tape bonded to their surfaces needs to be staggered to increase edge friction and avoid wrinkles caused by resin scouring. The calculation formula for the amount of shaping powder to be spread on the surface of each layer of sheet 3 is as follows: m=ρsa Wherein, m represents the amount of setting powder to be spread; ρ represents the surface density of the sheet; s represents the surface area of ​​the sheet; a represents the uniform spreading coefficient of the setting powder, and a=3%-6% D. Hot compaction: An isolation film, a breathable felt and a vacuum bag are placed on the surface of the laid sheet 3 in sequence for packaging, and then the whole is sent into an oven for hot compaction treatment. The hot compaction temperature is 60-90°C and the insulation time is 10-40 minutes. After the hot compaction treatment, it is naturally cooled, and the isolation film, breathable felt and vacuum bag are removed to obtain a semi-formed part of a torsion beam with large thickness for aviation, and the surface wrinkles of the semi-formed part of the torsion beam with large thickness for aviation are checked; If wrinkles appear on the surface of semi-formed parts of aviation torsion thick beams, use a heat source below 60-90℃ to treat the wrinkles. The specific process is as follows: Cover the surface of the semi-formed part of the aviation torsion thick beam with wrinkles with a layer of isolation film, use a heat source below 60~90℃ to iron the surface of the isolation film, and iron along the fiber direction until it is visually flat, then vacuum package and pre-compact once, the pre-compacting vacuum degree is ≥-90kpa, the time is ≥15min, repeat the above operation according to the wrinkles after pre-compacting until the wrinkles are eliminated; E. Flow channel layout: When the surface of the semi-formed part of the aviation torsion thick beam is free of wrinkles, a layer of demoulding cloth 6, a layer of guide net 7, 1 to 3 glue injection pipes 8 and a glue outlet pipe 9 are sequentially arranged on the surface of the semi-formed part of the aviation torsion thick beam; F. Packaging and curing: Finally, a vacuum bag 10 is arranged on the surface of the semi-formed part of the aviation torsion thick beam, and vacuum leakage detection is carried out. The vacuum degree of the leakage detection is -70~-95kpa, and the leakage detection time is 5-10min. After the vacuum leakage detection is completed, it is sent to the oven for curing and molding. The curing temperature is 150-185℃, and the insulation time is 2-3h to obtain the finished product of the aviation torsion thick beam.

[0019] In the present invention, the amount of shaping powder is calculated according to a coefficient of 3%-6% so that the spreading process is uniform and controllable, the edges of the sheet are fixed and locked at intervals of a certain number of layers to slow down the slippage between the sheets, and the hot compaction and natural cooling treatment at medium and low temperatures are performed to ensure the interlayer compaction of the entire part, which is convenient for observing wrinkles and processing them in time; the fiber layers of the part have a high degree of fit, the cured part has a good appearance, is wrinkle-free, and has high internal quality, the entire operation process is simple and controllable, the cost is low, and the molding difficulty is reduced.

[0020] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vacuum-assisted forming method for solving the wrinkles of torsion thick beams for aviation, characterized in that: The steps include: A. Applying resin: At room temperature, a high-grade toughened epoxy resin (2) is evenly applied to the surface of a single-sided mold (1), a layer of sheet (3) is laid on the high-grade toughened epoxy resin (2), and a pressure-sensitive adhesive tape (4) is used to fix and lock the edge of the sheet (3); B. Sprinkle setting powder: Evenly sprinkle shaping powder (5) on the surface of the layer of sheet (3) laid in step A; C. Paving and edge locking of the sheet: Continue to position and lay several layers of sheet (3) using a laser projector, and evenly spread shaping powder between each layer of sheet (3), and use a pressure-sensitive tape (4) to fix and lock the edges of the sheet (3) every 1-3 layers of sheet (3); D. Hot compaction: An isolation film, a breathable felt and a vacuum bag are placed on the surface of the laid material sheet (3) in sequence for packaging, and then the whole is sent into an oven for hot compaction treatment. After the hot compaction treatment, it is naturally cooled, and the isolation film, the breathable felt and the vacuum bag are removed to obtain a semi-formed part of a torsion beam with large thickness for aviation, and the surface wrinkles of the semi-formed part of the torsion beam with large thickness for aviation are checked; E. Flow channel layout: When the surface of the semi-formed part of the aviation torsion beam with large thickness is free of wrinkles, a layer of demoulding cloth (6), a layer of flow guide net (7) and a plurality of glue injection pipes (8) and glue outlet pipes (9) are sequentially arranged on the surface of the semi-formed part of the aviation torsion beam with large thickness; F. Packaging and curing: Finally, a vacuum bag (10) is arranged on the surface of the semi-formed part of the aviation torsion thick beam, and vacuuming and leak detection are performed. After the vacuuming and leak detection are completed, the semi-formed part is sent to an oven for curing and forming, thereby obtaining a finished aviation torsion thick beam.

2. A vacuum-assisted forming method for solving wrinkles in torsion thick beams for aviation according to claim 1, characterized in that: In steps B and C, the amount of shaping powder to be sprinkled on the surface of each layer of sheet (3) is calculated using the following formula: m=ρsa Wherein, m represents the amount of setting powder to be spread; ρ represents the surface density of the sheet; s represents the surface area of ​​the sheet; a represents the uniform spreading coefficient of the setting powder, and a=3%-6%.

3. A vacuum-assisted forming method for solving wrinkles of torsion thick beams for aviation according to claim 1, characterized in that: In step C, the edges of different layers of material sheets (3) are offset from each other.

4. The vacuum-assisted forming method for solving the wrinkles of torsion thick beams for aviation according to claim 1 is characterized in that: In step C, the edges of the material sheets (3) are fixed and locked using pressure-sensitive adhesive tapes (4) every 1-3 layers of the material sheets (3), and the pressure-sensitive adhesive tapes (4) are staggered.

5. The vacuum-assisted forming method for solving the wrinkles of torsion thick beams for aviation according to claim 1, characterized in that: In step D, the hot compaction temperature is 60-90° C., and the insulation time is 10-40 min.

6. The vacuum-assisted forming method for solving the wrinkles of torsion thick beams for aviation according to claim 1, characterized in that: In step D, if wrinkles appear on the surface of the semi-formed part of the aviation torsion thick beam, a heat source below 60-90°C is used to treat the wrinkles. The specific process is as follows: Cover the surface of the semi-formed parts of the aviation torsion thick beam with wrinkles with a layer of isolation film, use a heat source below 60~90℃ to iron the surface of the isolation film and iron along the fiber direction until it is visually flat, then vacuum package and pre-compact once, the pre-compacting vacuum degree is ≥-90kpa, the time is ≥15min, repeat the above operation according to the wrinkle situation after pre-compacting until the wrinkles are eliminated.

7. The vacuum-assisted forming method for solving the wrinkles of torsion thick beams for aviation according to claim 1 is characterized in that: In step E, 1 to 3 glue injection pipes (8) and 3 glue outlet pipes (9) are provided.

8. The vacuum-assisted forming method for solving wrinkles of torsion thick beams for aviation according to claim 1 is characterized in that: In step F, the leak detection vacuum degree is -70~-95kPa, and the leak detection time is 5-10min.

9. The vacuum-assisted forming method for solving the wrinkles of torsion thick beams for aviation according to claim 1, characterized in that: In step F, the curing temperature is 150-185° C. and the holding time is 2-3 hours.

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