Integral forming die and method for large composite barrel

Abstract

The invention relates to the technical field of composite material forming, and provides a large composite material barrel integrated forming die and method.The large composite material barrel integrated forming die comprises a core die, a flange positioning plate, a flange pressing plate, a pre-pressing plate and a flange surrounding strip; the core mold comprises a barrel mold, and the flange positioning plate is detachably arranged on the barrel mold; the flange foxing strip is detachably arranged on the flange positioning plate; the flange pressing plate is detachably arranged on the flange foxing strip, and the pre-pressing plate is arranged between the flange pressing plate and the flange foxing strip. According to the invention, the continuous winding fiber layer is laid into the flange structure in the form of the turnup of the winding fiber layer of the cylinder body, and after the composite material cylinder body is cured, the continuous fiber provides high-strength connection for the flange and the cylinder body, so that the integrity of the flange and the cylinder body structure is improved.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, specifically to a large composite material cylinder integral molding mold and method. Background Technology

[0002] Composite materials are widely used in modern military weaponry. In weapon launching systems, traditional metal launch tubes suffer from drawbacks such as high weight and density, which severely limit the mobility of weapon systems, especially on weight-sensitive vehicle-mounted and airborne platforms. Composite material launch tubes, on the other hand, are lightweight, high-strength, and corrosion-resistant, significantly reducing the maintenance costs of weapon launching systems.

[0003] In large composite material cylinders, the flanges are connected to the cylinder body using non-integral methods such as screws or adhesive bonding, which can lead to problems such as stress concentration and poor airtightness. It is also difficult for the flanges to maintain a good connection with the cylinder body during conditions such as hoisting, suspension, and vertical stacking of composite material cylinders. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a large composite material cylinder integral molding mold and method.

[0005] According to the present invention, a large composite material cylinder integral molding mold includes a core mold, a flange positioning plate, a flange pressure plate, a pre-pressure plate, and a flange strip. The core mold includes a cylindrical mold, and the flange positioning plate is detachably disposed on the cylindrical mold; the flange strip is detachably disposed on the flange positioning plate; the flange pressure plate is detachably disposed on the flange strip; the pre-pressure plate is an annular steel ring disposed between the flange pressure plate and the flange strip, and when the flange pressure plate is tightened, the pre-pressure plate can move toward the flange positioning plate.

[0006] Preferably, the flange positioning plate, flange pressure plate, and flange strip are all equipped with glue overflow grooves.

[0007] A method for integral molding of a large composite material cylinder according to the present invention includes the following steps: Step 1: Fibers are wound onto the cylindrical mold of the core mold to ensure that the fibers are evenly and completely wrapped around the cylindrical mold; Step 2: Cut the continuous fibers at both ends of the cylindrical mold, turn part of the fiber layer to the surface of the cylindrical mold and fix it; Step 3: Apply release agent to the molding die and install the flange positioning plate on the cylinder mold; Step 4: Lay prepreg on the flange positioning plate as a process layer; Step 5: Lay the fibers of the flanged cylinder mold onto the flange positioning plate in the order of interlayer. Step 6: After each layer of fiber is laid, the prepreg is laid on the fiber layer of the flange positioning plate; Step 7: Install the flange strip, preload plate, and flange pressure plate and tighten them by tightening the screws. Use a heating mantle to heat the molding mold and tighten the screws again to apply pressure. Step 8: After the molding mold temperature drops, remove the heating jacket, flange pressure plate, pre-pressure plate, and flange strip, and repeat step 4 until all the fiber layers fixed on the cylinder mold are laid onto the flange positioning plate. Step 9: Install the flange strip and flange pressure plate and tighten the screws to secure them; Step 10: Transfer the cylinder mold to the curing equipment for heating and curing; Step 11: After the cylinder is heated to a certain temperature, turn on the curing equipment, tighten the screws in the molding mold again and pressurize until the molding mold is closed. After the pressurization is completed, turn off the curing equipment and continue curing. Step 12: After curing, remove the flange pressure plate, flange strip, and flange positioning plate, and demold the product.

[0008] Preferably, in step 1, the winding length of the fiber on the mandrel is greater than the distance between the flanges at both ends of the cylinder; When performing fiber winding, the small-angle fiber layer that needs to be flanged should be isolated from the two ends of the fiber layer that has been wound onto the cylinder using breathable polytetrafluoroethylene release cloth, according to the required flange length.

[0009] Preferably, when the fiber layer is turned over to the core mold for fixing in step 2, the breathable polytetrafluoroethylene release fabric should also be turned over and fixed at the same time.

[0010] Preferably, in step 3, the release agent is applied 3 to 5 times, with an interval of 15 to 20 minutes between each application.

[0011] Preferably, in step 4, the reinforcement in the prepreg is unidirectional fiber, which is laid on the flange positioning plate in a segmented splicing manner, with a splice seam of 3-5 mm.

[0012] Preferably, in step 6, the prepreg is laid in a quasi-isotropic sequence of [0 / 90±45 / 90 / 0]n, where the value of n is designed according to the final thickness of the flange.

[0013] Preferably, in step 7, the heating rate of the heating jacket is 50℃ / h to 60℃ / h, the total heating time is 1h ≤ total heating time ≤ 2h, and the maximum temperature is less than the curing temperature of the resin system.

[0014] Preferably, the total operating time of the curing equipment is ≤1 hour.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention lays a continuous wound fiber layer into the flange structure by turning the edge of the wound fiber layer on the cylinder body. After the composite material cylinder body is cured, the continuous fiber provides a high-strength connection between the flange and the cylinder body, improving the integration of the flange and cylinder body structure. The cured cylinder flange is suitable for various complex working conditions.

[0016] 2. The present invention, through the design of the inner and outer mold structure of the flange forming mold, ensures that no defects such as insufficient glue or fiber buckling occur at the flange rounded corners during the curing process of the cylinder, thus guaranteeing the consistency and uniformity of the composite material cylinder structure.

[0017] 3. The present invention reduces the probability of internal defects such as delamination and looseness in the flange structure by designing a flange forming mold and applying mechanical pressure after heating the flange during the cylinder forming process. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the molding die in this invention. Only a part of the flange positioning plate is shown in the figure, and the other part is not shown. Figure 2 This is a schematic diagram of the layering in this invention. By inserting the small-angle wound fiber layer of the cylinder into the flange structure, the continuity of the fibers between the flange and the cylinder is ensured.

[0019] The diagram shows: Core mold 1; Cylinder mold 11; Flange positioning plate 2; Flange pressure plate 3; Flange strip 4. Detailed Implementation

[0020] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0021] Example 1: This invention provides a method for integral molding of a large composite material cylinder. The method involves flanging the wound fiber layer of the cylinder body. During the lay-up molding of the flange in the molding die, the wound fiber layer of the cylinder body is interwoven with the flange, ensuring the continuity of the fibers between the cylinder body and the flange after curing. This enhances the connection strength between the flange and the cylinder body and improves the integral molding of the composite material cylinder. The molding die is a metal structure and includes a core mold 1, a flange positioning plate 2, a flange pressure plate 3, a pre-pressure plate, and a flange retaining strip 4. Figure 1 As shown, the core mold 1 includes a cylindrical mold 11, and the flange positioning plate 2, flange pressure plate 3, and flange retaining strip 4 are all equipped with glue overflow grooves. The flange positioning plate 2 is detachably mounted on the cylindrical mold 11. Preferably, the flange positioning plate 2 is connected to the cylindrical mold 11 by a first screw, serving to determine the flange forming position. The flange retaining strip 4 is detachably mounted on the flange positioning plate 2. Preferably, the flange retaining strip 4 is connected to the flange positioning plate 2 by a second screw, serving to reduce resin loss. The flange pressure plate 3 is detachably mounted on the flange retaining strip 4. Preferably, the flange pressure plate 3 is connected to the flange retaining strip 4 by a third screw, serving to compact the flange and ensure the flange thickness. The pre-pressure plate is an annular steel ring, positioned between the flange pressure plate 3 and the flange retaining strip 4. When the flange pressure plate 3 is tightened, the pre-pressure plate can move towards the flange positioning plate 2, thereby ensuring that the flange thickness and shape meet the required requirements. This invention, through the connection design between the flange forming mold and the cylindrical core mold 1, helps to improve the flatness of the flange after forming and the positional accuracy of the cylindrical body.

[0022] Specifically, the method for integral molding of large composite material cylinders includes the following steps: Step 1: Fibers are wound onto the cylindrical mold 11 of the mandrel 1, ensuring the fibers are evenly and completely wrapped around the mold 11. The winding length of the fibers on the mandrel 1 should be greater than the distance between the flanges at both ends of the cylindrical body. During fiber winding, for the small-angle fiber layers requiring flange flanging, the ends of these fiber layers should be isolated from the ends of the fiber layers already wound onto the cylindrical body using a breathable PTFE release cloth, based on the required flanging length. The length of the breathable PTFE release cloth laid between the small-angle fiber layers requiring flange flanging should increase by 5–10 mm progressively. During fiber winding, the winding length of the 90° circumferential winding layer between the fiber layers requiring flanging should decrease by 50–100 mm progressively.

[0023] Step 2: Cut the continuous fibers at both ends of the cylindrical mold 11, and fold a portion of the fiber layer onto the surface of the cylindrical mold 11 and fix it. When folding the fiber layer onto the core mold 1 for fixation, the breathable polytetrafluoroethylene release fabric should also be folded onto and fixed. The number of fiber layers folded onto the core mold 1 for fixation should be designed according to the theoretical stress conditions of the flanges at both ends of the cylindrical body.

[0024] Step 3: Apply release agent to the molding mold and install flange positioning plate 2 on cylinder mold 11; apply release agent 3 to 5 times, with an interval of 15 to 20 minutes between each application.

[0025] Step 4: Lay prepreg on flange positioning plate 2 as a process layer; the reinforcement in the prepreg is unidirectional fiber, and it is laid on flange positioning plate 2 in a segmented splicing manner, with a splice joint of 3-5mm.

[0026] Step 5: Lay the fibers of the flanged cylinder mold 11 onto the flange positioning plate 2 in the order of interlayer. After each layer of fibers is laid, trim the fibers so that the length of the fibers laid on the flange positioning plate 2 is not higher than the forming height of the flange.

[0027] Step 6: After each layer of fiber is laid, the prepreg is laid on the fiber layer of the flange positioning plate 2; the prepreg should be laid in the order of [0 / 90±45 / 90 / 0]n quasi-isotropic sequence, where the value of n is designed according to the final thickness of the flange.

[0028] Step 7: Install and tighten the flange strip 4, pre-pressure plate, and flange pressure plate 3, preferably by tightening screws. Use a heating mantle to heat the molding die, and tighten the screws again to apply pressure. The total thickness of the prepreg, the flanged fiber layer, and the pre-pressure plate should be 3-5 mm greater than the flange design thickness. The heating mantle heating rate is 50℃ / h-60℃ / h, and the total heating time is 1h ≤ total heating time ≤ 2h. The maximum temperature is less than the curing temperature of the resin system.

[0029] Step 8: After the temperature of the molding die drops, remove the heating jacket, flange pressure plate 3, pre-pressure plate, and flange strip 4, and repeat step 4 until all the fiber layer fixed on the cylinder mold 11 is laid on the flange positioning plate 2. Step 9: Install and tighten the flange strip 4 and flange pressure plate 3 by tightening the screws; after tightening the screws, the total thickness of the prepreg and fiber layer is 3-5 mm greater than the final thickness of the flange.

[0030] Step 10: Transfer the cylindrical mold 11 to the curing equipment for heating and curing; Step 11: After the cylinder is heated to a certain temperature, turn on the curing equipment, tighten the screws in the molding mold again to pressurize the molding mold until it closes, and turn off the curing equipment after pressurization to continue curing; wherein, the certain temperature is the minimum temperature at which the resin system begins to crosslink, and the total time the curing equipment is turned on is ≤1h.

[0031] Step 12: After curing, remove flange pressure plate 3, flange strip 4, and flange positioning plate 2, and demold the product.

[0032] Example 2: This embodiment is a preferred example of Embodiment 1. This embodiment provides a method for integral molding of a large composite material cylinder, including the following steps: Step 1: Fibers are wound onto the cylindrical mold 11 of the core mold 1, ensuring the fibers are evenly and completely wrapped around the cylindrical mold 11. There are a total of 25 fiber winding layers. Starting from the 7th winding layer, the winding length of the subsequent 90 winding layers decreases by 100mm at each step. Starting from the 7th layer, before each subsequent small-angle winding layer (i.e., ±45° / ±10°), a 50mm-55mm wide breathable PTFE release cloth is used to isolate the winding layers at both ends of the cylinder. The PTFE release cloth increases by 50mm-55mm at each step, for a total of 10 small-angle fiber winding layers to be rolled up to the flange.

[0033] Step 2: Cut the continuous fibers at both ends of the cylindrical mold 11, turn the 10 layers of fiber to be turned over to the surface of the cylindrical mold 11 and fix it by wrapping it with a 50mm to 55mm wide breathable PTFE release cloth.

[0034] Step 3: Apply release agent 5 to 6 times to the molding mold, with an interval of 15 to 20 minutes each time, and install the flange positioning plate (2) on the cylinder mold 11.

[0035] Step 4: Lay 20 layers of prepreg on the flange positioning plate 2 as a process sacrificial layer. Each layer of prepreg is made up of 4 pieces of prepreg spliced ​​together, and use a utility knife to cut off the prepreg that is higher than the flange shape.

[0036] Step 5: Lay the fibers of the flanged cylinder mold 11 onto the flange positioning plate 2 in the order of interlayer.

[0037] Step 6: After each layer of fiber is laid, lay 6 layers of prepreg (angle: 0° / 90° / ±45° / 90° / 0°) on the fiber layer of flange positioning plate 2 in sequence.

[0038] Step 7: After turning the 5-layer fiber winding layer over the flange positioning plate 2 and laying the prepreg, install the flange strip 4, pre-pressure plate, and flange pressure plate 3, tighten the screws, use the heating jacket to heat the flange forming mold to 60℃~80℃ and keep it at that temperature for 20min~30min, then tighten the screws again to apply pressure.

[0039] Step 8: After the molding mold temperature drops to room temperature, remove the heating jacket, flange pressure plate 3, pre-pressure plate, and flange strip 4, and repeat step 4 to lay all the remaining 10 layers of fiber winding fixed on the cylinder onto the flange positioning plate 2.

[0040] Step 9: Install the flange strip 4 and flange pressure plate 3, and tighten the screws.

[0041] Step 10: Transfer the cylinder to the curing equipment for heating and curing.

[0042] Step 11: After the cylinder is heated to a certain temperature, turn on the curing equipment, tighten the screws in the molding mold again to apply pressure until the molding mold is closed, and turn off the curing equipment after the pressure is applied to continue curing.

[0043] Step 12: After curing, remove flange pressure plate 3, flange strip 4, and flange positioning plate 2, and demold the product.

[0044] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0045] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A large composite material cylinder integral molding mold, characterized in that, Includes core mold (1), flange positioning plate (2), flange pressure plate (3), pre-pressure plate and flange strip (4); The core mold (1) includes a cylindrical mold (11), and the flange positioning plate (2) is detachably disposed on the cylindrical mold (11); the flange strip (4) is detachably disposed on the flange positioning plate (2); the flange pressure plate (3) is detachably disposed on the flange strip (4), and the pre-pressure plate is an annular steel ring disposed between the flange pressure plate (3) and the flange strip (4). When the flange pressure plate (3) is tightened, the pre-pressure plate can move toward the flange positioning plate (2).

2. The large composite material cylinder integral molding mold according to claim 1, characterized in that, The flange positioning plate (2), flange pressure plate (3), and flange strip (4) are all equipped with glue overflow grooves.

3. A method for integral molding of a large composite material cylinder, characterized in that, Includes the following steps: Step 1: Fibers are wound onto the cylindrical mold (11) of the core mold (1) so that the fibers are evenly and completely wrapped on the cylindrical mold (11); Step 2: Cut the continuous fibers at both ends of the cylindrical mold (11), turn part of the fiber layer to the surface of the cylindrical mold (11) and fix it; Step 3: Apply release agent to the molding die and install the flange positioning plate (2) on the cylindrical die (11); Step 4: Lay prepreg on the flange positioning plate (2) as a process layer; Step 5: Lay the fibers of the flanged cylinder mold (11) onto the flange positioning plate (2) in the order of interlayer; Step 6: After each layer of fiber is laid, the prepreg is laid on the fiber layer of the flange positioning plate (2); Step 7: Install flange strip (4), pre-pressure plate, flange pressure plate (3) and tighten them by tightening screws. Use heating jacket to heat the forming mold and tighten the screws again to apply pressure. Step 8: After the temperature of the molding die drops, remove the heating jacket, flange pressure plate (3), pre-pressure plate, flange strip (4), and repeat step 4 until all the fiber layer fixed on the cylinder mold (11) is laid on the flange positioning plate (2). Step 9: Install the flange strip (4) and flange pressure plate (3) and tighten the screws to secure them; Step 10: Transfer the cylindrical mold (11) to the curing equipment for heating and curing; Step 11: After the cylinder is heated to a certain temperature, turn on the curing equipment, tighten the screws in the molding mold again and pressurize until the molding mold is closed. After the pressurization is completed, turn off the curing equipment and continue curing. Step 12: After curing, remove the flange pressure plate (3), flange strip (4), and flange positioning plate (2) to demold the product.

4. The method for integral molding of large composite material cylinders according to claim 3, characterized in that, In step 1, the winding length of the fiber on the mandrel (1) is greater than the distance between the flanges at both ends of the cylinder; When performing fiber winding, the small-angle fiber layer that needs to be flanged should be isolated from the two ends of the fiber layer that has been wound onto the cylinder using breathable polytetrafluoroethylene release cloth, according to the required flange length.

5. The method for integral molding of large composite material cylinders according to claim 3, characterized in that, When the fiber layer is turned over to the core mold (1) in step 2 for fixing, the breathable polytetrafluoroethylene release fabric should also be turned over and fixed.

6. The method for integral molding of large composite material cylinders according to claim 3, characterized in that, In step 3, the release agent is applied 3 to 5 times, with an interval of 15 to 20 minutes between each application.

7. The method for integral molding of large composite material cylinders according to claim 3, characterized in that, In step 4, the reinforcing material in the prepreg is unidirectional fiber, which is laid on the flange positioning plate (2) in a segmented splicing manner, with a splice seam of 3-5 mm.

8. The method for integral molding of large composite material cylinders according to claim 3, characterized in that, In step 6, the prepreg is laid in a quasi-isotropic sequence of [0 / 90±45 / 90 / 0]n, where the value of n is designed according to the final thickness of the flange.

9. The method for integral molding of a large composite material cylinder according to claim 3, characterized in that, In step 7, the heating rate of the heating jacket is 50℃ / h to 60℃ / h, the total heating time is 1h ≤ total heating time ≤ 2h, and the maximum temperature is less than the curing temperature of the resin system.

10. The method for integral molding of a large composite material cylinder according to claim 3, characterized in that, The total operating time of the curing equipment is ≤1 hour.

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