Large-length-diameter-ratio thin-wall composite material tubular beam manufacturing tool
Through the combined tooling of foam core mold and tubular air bag, the problem of demolding of large-length-diameter thin-wall composite pipe beams and mold deformation is solved, and high-precision molding and low-cost production are achieved.
Patent Information
- Application Number
- CN202422212330.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-09-10
AI Technical Summary
In the prior art, when preparing thin-wall composite pipe beams with large length-to-diameter ratios, there are problems such as difficult demolding, mold deformation, and poor product straightness and poor surface quality, and the production cost is relatively high.
The combined tooling of foam core mold and tubular air bag is used to splice into a foam core mold through EPS foam blocks, and the tubular air bag is expanded and formed, combining with the mold cavity of the metal mold to ensure the straightness and surface quality of the product, while avoiding the use of hot pressing tank equipment.
High-precision molding of large-length diameter thin-wall composite pipe beams is achieved, with smooth surface and dense internal structure, reducing production costs.
Smart Images
Figure CN223147812U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of composite material pipe beam preparation tooling, in particular to a preparation tooling for a large aspect ratio thin-walled composite material pipe beam. Background Technique
[0002] At present, the application scope of advanced composite materials in the field of aircraft manufacturing is continuously expanding, from various secondary load-bearing structures such as floors and fairings to main load-bearing structural parts. The beam structural part is the main load-bearing structure of the aircraft, with large size, large weight ratio, and complex stress. Using carbon fiber composite materials to make beam structural parts can reduce the structural weight and improve the stiffness, which is of great significance.
[0003] The composite material beam structural part of a large unmanned aerial vehicle has the structural characteristics of a large aspect ratio and a thin wall thickness. When using the conventional metal male mold laying - vacuum bag molding - autoclave curing process, there are problems such as difficult demolding, poor mold stiffness affecting the straightness of the product, and poor outer surface quality, which are difficult to meet the high-precision dimensional requirements during the assembly of the aircraft pipe beam, and the production cost is relatively high. Content of the Utility Model
[0004] The utility model provides a preparation tooling for a large aspect ratio thin-walled composite material pipe beam to overcome the deficiencies and defects mentioned in the above background technique.
[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:
[0006] A preparation tooling for a large aspect ratio thin-walled composite material pipe beam, including a metal mold, further including a foam core mold and a tubular air bag. The tubular air bag is tightly sleeved on the outer wall of the circumferential direction of the foam core mold and then the whole is placed in the mold cavity of the metal mold. One axial end of the tubular air bag is closed and the other axial end is open, and an inflation joint is connected to the open end of the tubular air bag, and the inflation joint is connected to an external air supply pipeline.
[0007] Further, the foam core mold is composed of multiple sections of EPS foam blocks spliced together, and adjacent EPS foam blocks are fixedly pasted.
[0008] Further, both the sealed end and the open end of the tubular air bag are reserved with a surplus.
[0009] When preparing a large aspect ratio thin-walled composite material tube beam using the present utility model, the external shape size and surface quality of the product formed by EPS foam + airbag internal expansion can be guaranteed by a metal mold, and the metal mold does not need to be supported in the air during curing, so no flexural deformation will occur. The product prepared by the present utility model has good straightness, high dimensional accuracy, smooth surface, and dense internal structure, overcoming the problems existing in the conventional method of laying with a metal male mold - vacuum bag molding - autoclave curing for large aspect ratio thin-walled composite material tube beams, such as difficult demolding, out-of-tolerance straightness of the product caused by mold deformation, and poor surface quality. Moreover, it does not need to use autoclave equipment, reducing production costs, and has obvious advantages in the forming of large aspect ratio thin-walled composite material tube beams. Brief Description of the Drawings
[0010] Figure 1 It is a schematic cross-sectional structure view of an embodiment of the present utility model:
[0011] Figure 2 It is a schematic longitudinal sectional structure view of an embodiment of the present utility model:
[0012] Reference numerals in the figure: 1 - foam core mold; 2 - airbag; 3 - sheet material; 4 - upper metal mold; 5 - lower metal mold; 6 - metal mold locking bolt; 7 - inflation joint; 8 - gas supply pipeline. Detailed Embodiment
[0013] The present utility model will be further described below with reference to the drawings and embodiments.
[0014] This embodiment discloses a preparation tooling for a large aspect ratio thin-walled composite material circular variable cross-section tube beam, as Figures 1 to 2 shown, which includes a metal mold. The metal mold includes an upper metal mold 4 and a lower metal mold 5 connected integrally by bolts 6, and a complete mold cavity is formed by the upper mold cavity of the upper metal mold 4 and the lower mold cavity of the lower metal mold 5.
[0015] This embodiment also includes a foam core mold 1 and a tubular airbag 2. The foam core mold 1 is assembled by splicing multiple segments of EPS foam blocks according to the required dimensions, and the butt joints of adjacent EPS foam blocks are fixed by pasting with paper tape. The tubular airbag 2 is tightly sleeved on the outer wall of the circumference of the foam core mold 1 and then placed as a whole in the mold cavity of the metal mold. One axial end of the tubular airbag 2 is closed and the other axial end is open, and both the sealed end and the open end of the tubular airbag 2 have a margin relative to the corresponding axial ends of the foam core mold 1. Among them, an inflation joint 7 is hermetically connected to the open end of the tubular airbag 2, and the inflation joint 7 is connected to an external gas supply pipeline 8.
[0016] The preparation method of using this embodiment to prepare a large aspect ratio thin-walled composite material tube beam is as follows:
[0017] Step S1: Assemble multiple segments of EPS foam blocks into the foam core mold 1 according to the required dimensions. At the butt joints of adjacent EPS foam blocks, paste and fix them with paper tape. The size of each segment of EPS foam block is reduced by 1 - 2 mm on each side compared to the inner surface size of the finally produced product.
[0018] Step S2: Put a tubular airbag 2 with a width of 140 mm (circumference of 280 mm) over the foam core mold 1. The material of the tubular airbag 2 is nylon, or latex, or polyester. One axial end of the tubular airbag 2 is open, and the other axial end is sealed. The length of the tubular airbag 2 is greater than the total length of the foam core mold 1, and a margin of 100 - 150 mm is reserved at the sealed end of the tubular airbag 2, and a margin of 200 - 250 mm is reserved at the open end of the tubular airbag 2.
[0019] Then, seal the open end of the tubular airbag 2 with a sealing tape and connect a vacuum nozzle. Through the vacuum nozzle at the open end, evacuate the inside of the tubular airbag 2, so that the tubular airbag 2 tightly wraps and adheres to the outer wall of the foam core mold 1.
[0020] Step S3: Lay 9 layers of prepreg sheets 3 on the outer wall of the tubular airbag 2. The prepreg is one or several of carbon fiber resin prepreg, glass fiber resin prepreg, and aramid fiber resin prepreg.
[0021] When laying, each layer of prepreg is composed of multiple spliced sheets. The splicing seams are butt - jointed between adjacent sheets along the fiber direction, and the butt - joint gap is 0 - 2 mm. The splicing seams between adjacent sheets perpendicular to the fiber direction are overlapped, and the overlap width is 15 - 20 mm. The splicing seams of the upper and lower layers of prepreg in the thickness direction are staggered by at least 30 mm.
[0022] Step S4: Transfer the foam core mold 1 and the tubular airbag 2 with the sheets laid on it as a whole to the lower mold cavity of the metal lower mold 5 in the metal mold. Seal - connect an inflation joint 7 at the open end of the tubular airbag 2 and place the inflation joint 7 in the card slot at the end of the metal lower mold 5. Then, close the metal upper mold 4 of the metal mold on the metal lower mold 5 to form a complete metal mold. The complete mold cavity is composed of the lower mold cavity of the metal lower mold 5 and the upper mold cavity of the metal upper mold 4, so that the tubular airbag 2 and the foam core mold 1 are placed as a whole in the mold cavity of the metal mold, and pressurize through the bolts 6 connecting the upper and lower metal molds to make the mold - closing gap between the upper and lower metal molds meet the process requirements (less than 0.1 mm in this embodiment).
[0023] Step S5: Connect the external gas supply pipeline 8 to the inflation joint 7 at the end of the metal mold 5, slowly fill high - pressure gas into the airbag 2, and use the air - inflation pressure to make the laid sheets 3 fully adhere to the mold cavity of the metal mold. Then, send the metal mold into the oven for heating and curing. The heating and curing process is as follows:
[0024] First, pressurize step by step in increments of 0.1 MPa to the target pressure of 0.8 - 1.5 MPa, and hold the pressure for 3 - 5 minutes at each step; after reaching the target pressure of 0.8 - 1.5 MPa, start running the curing curve: heat at a rate of 0.5 - 2 °C per minute to 60 - 100 °C, keep the temperature for 0.5 - 1 hour, then continue to heat to 120 - 150 °C and keep the temperature for 1 - 3 hours; finally, release the pressure when the temperature drops to no more than 60 °C, thus completing the heating and curing molding.
[0025] In this embodiment, the target pressure for stepwise pressurization within the range of 0.8 - 1.5 MPa can meet the requirements of the molding process. However, through experiments, considering the pressure-bearing capacity of the airbag and the internal quality of the product comprehensively, the optimal value of the target pressure is 1.2 MPa.
[0026] S6. Since the EPS foam will shrink during the heating process, the product can be obtained immediately after demolding at the end of curing, and the residues of the tubular airbag 2 and the foam core mold 1 are extracted from the interior of the product, thereby obtaining the tubular beam product.
[0027] For the large aspect ratio thin-walled composite material tubular beam product prepared in this embodiment, the cross-sectional shape of the tubular beam can be circular, or oval, or rounded rectangular, or other geometric shapes, and the cross-sectional size of the tubular beam is constant cross-section or variable cross-section. During specific preparation, only a foam core mold 1 with a suitable cross-section and a metal mold with a matching cross-section in the mold cavity need to be selected to complete the preparation.
[0028] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. The embodiments described in the present invention are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Among the various specific technical features described in the above specific embodiments, they can be combined in any suitable way without contradiction. As long as such a combination does not violate the idea of the present invention, it should also be regarded as the content disclosed in the present disclosure. To avoid unnecessary repetition, the present invention does not further explain various possible combination methods.
[0029] The present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention and without departing from the design idea of the present invention, various modifications and improvements made by those skilled in the art to the technical solution of the present invention should all fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.
Claims
1. A preparation tooling for a thin-walled composite material pipe beam with a large aspect ratio, including a metal mold, characterized in that, It further includes a foam core mold and a tubular airbag. The tubular airbag is tightly sleeved on the outer wall of the circumferential direction of the foam core mold and then the whole is placed in the mold cavity of the metal mold. One axial end of the tubular airbag is closed and the other axial end is open, and an inflation joint is connected to the open end of the tubular airbag. The inflation joint is connected to an external air supply pipeline.
2. The preparation tooling for a thin-walled composite material pipe beam with a large length-diameter ratio according to claim 1, characterized in that, The foam core mold is formed by splicing multiple segments of EPS foam blocks, and adjacent EPS foam blocks are fixedly pasted together.
3. The manufacturing tooling for a large aspect ratio thin-walled composite material tube beam according to claim 1, characterized in that, Surplus amounts are reserved at both the sealed end and the open end of the tubular airbag.