Composite material covering cap for tightness test and forming method

Abstract

The invention discloses a composite material covering cap for a tightness test and a forming method in the field of composite material products, and the forming method comprises the following steps: 1) preparing a mold which is a flat plate mold; 2) pre-embedding and paving the prepreg and the internal and external thread adapter, placing two embedded parts of the internal and external thread adapter in the middle of the prepreg, and cutting off the prepreg to wrap the embedded parts; 3) curing: manufacturing a product into a vacuum bag, transferring the vacuum bag into an autoclave, vacuumizing the vacuum bag, charging the autoclave with positive pressure, and running a final curing process according to curing parameters of the prepreg until the prepreg is taken out of the autoclave; and (4) demolding is conducted, the vacuum bag is removed, the mold is dismantled, and the integrally-formed composite material covering cap with the two internal and external thread conversion connectors is obtained. While the airtightness requirement and the strength requirement of the device are met, the tightness test is simply, conveniently and efficiently completed; the problem of air leakage after the resin-based composite material and the metal are compounded is solved, so that the airtight requirement and the strength requirement are met, the working efficiency is improved, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The invention relates to a molding method of a composite material mouth cover, in particular to a composite material mouth cover for tightness test and a molding method thereof. Background Art

[0002] The hull tightness test refers to checking whether the hull liquid tanks and other compartments meet the requirements of watertightness or wind and raintightness. Common tightness test methods include water filling method, water flushing method, kerosene coating inspection method, compressed air method, and vacuum test method. The compressed air method is widely used because of its good working conditions, clean working environment, high inspection sensitivity, and is very suitable for the inspection of closed hull compartments. The compressed air method inflates the closed space through the air intake device, closes the valve after reaching the test air pressure, maintains it for a certain period of time, and checks whether the pressure will decrease. If the air pressure does not decrease significantly, the test is qualified, and the valve is opened to discharge the gas in the space; if the air pressure decreases significantly, it means that the closed space is leaking and the test fails.

[0003] Traditional covers used for tightness tests are mostly made of steel or aluminum, which are prone to distortion and cannot meet their own airtightness requirements. They are also affected by the environment and corroded during placement, and will produce metal fatigue after repeated use. Compared with metal materials, composite materials have strong designability, high specific strength, high specific modulus, and can be reused many times. In recent years, they have been widely used in aerospace, automobiles, construction, electronic products, sports equipment and other fields. In addition, after metal parts are compounded with resin-based composite materials, air leakage is common. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a composite material mouth cover and a molding method for tightness testing, which forms an integrally molded composite material mouth cover with two internal and external thread conversion joints, and completes the tightness test simply and efficiently while meeting its own airtightness requirements and strength requirements; and solves the problem of air leakage after the resin-based composite material and metal are composited, thereby meeting the airtightness requirements and strength requirements, improving work efficiency and reducing manufacturing costs.

[0005] The object of the present invention is achieved by: a composite material cover molding method for tightness test, comprising the following steps: 1) Unloading: Take out the carbon fiber prepreg from the freezer and cool it at room temperature for later use; 2) Prepare the mold: The mold is a flat mold, degrease the mold and apply a release agent, and use an automatic cloth cutting machine to cut the prepreg sheets at various angles required for the layering for use; 3) Surface treatment of carbon steel joints: The surface of carbon steel joints is sandblasted, and the joints after sandblasting need to be pasted with adhesive film within a certain period of time; 4) Joint wrapping film: Wrap the lower end of the joint after sand blowing with film. After wrapping, lay non-porous isolation film, breathable felt, vacuum bag film on the surface, and connect the vacuum nozzle to vacuum; 5) Pre-embedded paving of prepreg and internal and external wire conversion joints: Place two internal and external wire conversion joint embedded parts in the center of the prepreg, cut the prepreg to wrap the embedded parts; 6) Bag making: After the plying is completed, trim off the messy and excess prepreg that is higher than the lower end of the joint, remove the pre-evacuated bag, lay the peelable cloth, lay the isolation film, wrap the upper end of the joint with an appropriate amount of raw silica gel, and then lay the breathable felt, vacuum bag film, place the vacuum nozzle, and vacuumize to shape; 7) Curing: After bag making is completed, it is transferred to the autoclave, the vacuum bag is evacuated with negative pressure, the autoclave is filled with positive pressure, and the final curing process is carried out according to the curing parameters of the prepreg until it is out of the can; 8) Demolding: Remove the vacuum bag, dismantle the mold, and obtain an integrally molded composite material mouth cover with two internal and external thread conversion joints.

[0006] As a further limitation of the present invention, the step 5) specifically includes: 5-1) Lay 15 layers of cut carbon fiber prepreg sheets on the mold, lay non-porous isolation film, breathable felt, and vacuum bag film on the surface, connect the vacuum nozzle, and evacuate; 5-2) Open the vacuum bag, locate the two joints at a certain distance on the center line of the length direction of the carbon fiber prepreg, make a cross-shaped cut, place the embedded parts from bottom to top, and then continue to lay fifteen layers of carbon fiber prepreg, make a cut at the joint and wrap the embedded parts, seal the pre-vacuum bag, and continue to vacuum.

[0007] As a further limitation of the present invention, the sand blasting parameters of the sand blasting treatment in step 3) are 100 mesh quartz sand, wind pressure: 0.6~0.8MPa, the inclination between the sand blasting nozzle and the sand blasted surface is 30°~60°, the distance between the sand blasting nozzle and the joint is 150mm~300mm, and the translation speed of the sand blasting nozzle is 0.5~1m / min; the joint after sand blasting needs to be affixed with a film within 6 hours.

[0008] Another aspect of the purpose of the present invention is achieved as follows: A composite material mouth cover for tightness testing, comprising a mouth cover body, on which a quick-connect air valve and a pressure gauge are provided; the mouth cover body is provided with two internal and external thread conversion joints, the upper ends of the two internal and external conversion joints are respectively connected to the quick-connect air valve and the pressure gauge, and the lower ends are communicated with the closed space of the hull; the mouth cover body transmits gas to the closed space of the hull through the air inlet and outlet channels in the quick-connect air valve.

[0009] As a further limitation of the present invention, the quick-connect connector gas valve is provided with inlet and outlet gas channels, and the inlet and outlet gas channels are used for gas transmission; the quick-connect connector gas valve controls the opening and closing of the inlet and outlet gas channels.

[0010] As a further limitation of the present invention, the quick-connect fitting gas valve and the pressure gauge are spaced apart.

[0011] As a further limitation of the present invention, the quick-connect joint air valve is threadedly connected to the mouth cover body; the pressure gauge is threadedly connected to the mouth cover body.

[0012] As a further limitation of the present invention, an upper end of the quick-connect fitting air valve is connected to an air pipe.

[0013] The present invention adopts the above technical scheme, and compared with the prior art, the beneficial effects are as follows: the mouth cover body is made of composite material and resin, does not contain any metal, has a relatively low density, and meets the requirements of small weight and light weight; the main body prepared by carbon fiber prepreg can be reused many times. The prepreg paving autoclave molding method is adopted, and the raw material used is prepreg, which has controllable quality and stable performance, reduces the porosity of the composite material, and improves its airtightness and strength. The mouth cover body adopts an integrated molding method, which is simple and fast and ensures the sealing between components; the mouth cover body is threadedly connected with the quick-connect air valve and the pressure gauge to ensure sealing, and is easy to operate and use; the quick-connect air valve controls the inlet and outlet of air at the same time, and is easy to operate; a good tightness test mouth cover can effectively shorten the test cycle and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 The process flow of the method of the present invention.

[0016] Figure 2 A schematic structural diagram of the mouth cover of the present invention.

[0017] Among them, 1 is the air inlet and outlet channel, 2 is the quick-connect air valve, 3 is the pressure gauge, and 4 is the cover body. DETAILED DESCRIPTION

[0018] 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.

[0019] like Figure 1 A composite material cover molding method for tightness test is shown. In this embodiment, the joint thread specification is M14*1.5, the length is 1.5 inches, the material is carbon steel, and T700 / E1301 unidirectional prepreg is used. The method specifically includes the following steps: Step 1) Unloading: Take out the T700 / E1301 prepreg from the freezer, cool it at room temperature for more than 6 hours, and set it aside. The prepreg is very convenient to cut and lay, and can achieve different fiber orientations. The resin content is evenly distributed, which effectively guarantees the performance and quality of the product while improving process efficiency. Step 2) Prepare the mold: The mold is a flat mold, degrease the mold and apply the release agent for more than three times, with an interval of more than 15 minutes between each time; use an automatic cloth cutting machine to cut the prepreg sheets at various angles required for the layering and set them aside; Step 3) Sand blasting of carbon steel joints: The sand blasting parameters are 100 mesh quartz sand, wind pressure: 0.6~0.8MPa, the inclination between the sand blasting nozzle and the sand blasted surface is 30°~60°, the distance between the sand blasting nozzle and the joint is 150mm~300mm, and the translation speed of the sand blasting nozzle is (0.5~1)m / min. The joints after sand blasting need to be affixed with adhesive film within 6 hours; Step 4) Wrap the joint with film: Wrap the lower end of the joint after sandblasting with film. After wrapping, lay a non-porous isolation film, breathable felt, and vacuum bag film on the surface to connect the vacuum nozzle. Vacuum for more than 15 minutes to ensure that the joint and the film are tightly bonded. Step 5) Pre-embedded and laid prepreg and internal and external wire conversion joints: Place two internal and external wire conversion joint embedded parts in the center of the prepreg, cut the prepreg and wrap the embedded parts; Lay 15 layers of cut T700 / E1301 prepreg sheets on the mold, lay non-porous isolation film, breathable felt, vacuum bag film on the surface to connect the vacuum nozzle, and evacuate for more than 15 minutes; Remove the vacuum bag, locate the placement of two joints at a certain distance on the midline of the length direction of the carbon fiber prepreg, make a cross-shaped cut, place the embedded parts from bottom to top, and then continue to lay 15 layers of carbon fiber prepreg, make a cut at the joint and wrap the embedded parts, seal the pre-vacuum bag, and continue to evacuate for more than 15 minutes.

[0020] Step 6) Bag making: After the plying is completed, trim off the messy excess prepreg that is higher than the lower end of the joint to prevent difficulty in demoulding later. Remove the pre-vacuum bag, lay the peelable cloth, lay the isolation film, and wrap the upper end of the joint with an appropriate amount of raw silicone to make it round and not easy to burst. Then lay the breathable felt and vacuum bag film in turn, place the vacuum nozzle, vacuumize and shape, and test the vacuum bag to ensure there is no leakage; Step 7) Curing: After the bag is made, it is transferred to the autoclave. In order to ensure the air tightness and appearance quality of the lid, according to the T700 / E1301 prepreg resin system, an external pressure of 0.2MPa is selected, and the temperature and pressure are maintained at 125℃ for 3h before being taken out of the can; Step 8) Demolding: Remove the vacuum bag, dismantle the mold, and obtain an integrally molded composite material mouth cover with two internal and external thread conversion joints.

[0021] like Figure 2 As shown, a composite material mouth cover for tightness test includes a mouth cover body 4, on which a quick-connection air valve 2 and a pressure gauge 3 are arranged; the mouth cover body 4 is provided with two internal and external thread conversion joints, the upper ends of the two internal and external conversion joints are respectively connected to the quick-connection air valve 2 and the pressure gauge 3, and the lower ends are communicated with the tight space of the hull; the quick-connection air valve 2 is provided with an inlet and outlet channel 1, and the inlet and outlet channel 1 is used for gas transmission; the mouth cover body 4 transmits gas to the closed space of the hull through the inlet and outlet channel 1 in the quick-connection air valve 2; the quick-connection air valve 2 controls the on-off of the inlet and outlet air channels 1; a nut is provided at the lower end of the quick-connect joint air valve 2, and the thread specification is M14*1.5; the quick-connect joint air valve 2 is threadedly connected to the cover body 4; a nut is provided at the lower end of the pressure gauge 3, and the thread specification is M14*1.5, and the pressure gauge 3 is threadedly connected to the cover body 4; an air pipe is connected to the upper end of the quick-connect joint air valve 2; the quick-connect joint air valve 2 and the pressure gauge 3 are placed at intervals, so that the quick-connect joint air valve 2 can be quickly closed when the value of the pressure gauge 3 is observed, so that the air intake can be stopped immediately when the quick-connect joint air valve 2 is closed.

[0022] In the actual practical process, the hull hatch is polished and roughened, and the cover plate is placed on the hatch, and fixed with 10mm thick narrow strips of dry material by hand to ensure its sealing. The cover body 4 transmits gas to the closed space of the hull through the inlet and outlet channels 1 in the quick-connect valve 2; when conducting the tightness test, the quick-connect valve 2 is opened, and compressed air is delivered to the closed space of the hull through the inlet and outlet channels 1. The pressure gauge 3 monitors the cabin pressure in real time and displays the pressure value. During the test, the pressure is tested and maintained at 5Kpa, 10kpa, 15kpa, 20kpa, 25kpa, and 30kpa respectively. The pressure gauge 3 reading does not drop after maintaining the pressure for 30 minutes, which is qualified. After the test is completed, the quick-connect valve 2 is opened to allow the gas in the closed space to be discharged through the inlet and outlet channels 1, and then the connection between the cover plate and the hull hatch is released to complete the tightness test.

[0023] In actual use, when the quick-connection air valve 2 or the pressure gauge 3 is damaged, the damaged quick-connection air valve 2 or the pressure gauge 3 can be unscrewed and replaced with a new quick-connection air valve 2 or the pressure gauge 3 in time, thereby extending the service life of the cover plate. At the same time, it can avoid the device being unusable due to damage to the quick-connection air valve 2 or the pressure gauge 3, thereby delaying the hull tightness test.

[0024] In the actual practical process, the hull hatch is polished and roughened, and the hatch cover is placed on the hatch, and fixed with 10mm thick narrow strips of dry material by hand to ensure its sealing. The hatch cover transmits gas to the closed space of the hull through the inlet and outlet channels 1 in the quick-connection air valve 2 for tightness test.

[0025] The cover body 4 is an integrally formed composite cover plate with two internal and external thread conversion joints. The thread specifications of the two conversion joints are M14*1.5. The external threads at the upper ends can match the internal threads at the lower ends of the air valve and pressure gauge 3 to achieve threaded connection. The lower ends are connected to the hull's airtight space to more accurately display the cabin air pressure in real time.

[0026] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A composite material cover molding method for tightness test, characterized in that: The following steps are involved: 1) Unloading: Take out the carbon fiber prepreg from the freezer and cool it at room temperature for later use; 2) Prepare the mold: The mold is a flat mold, degrease the mold and apply a release agent, and use an automatic cloth cutting machine to cut the prepreg sheets at various angles required for the layering for use; 3) Surface treatment of carbon steel joints: The surface of carbon steel joints is sandblasted, and the joints after sandblasting need to be pasted with adhesive film within a certain period of time; 4) Joint wrapping film: Wrap the lower end of the joint after sand blowing with film. After wrapping, lay non-porous isolation film, breathable felt, vacuum bag film on the surface, and connect the vacuum nozzle to vacuum; 5) Pre-embedded paving of prepreg and internal and external wire conversion joints: Place two internal and external wire conversion joint embedded parts in the center of the prepreg, cut the prepreg to wrap the embedded parts; 6) Bag making: After the plying is completed, trim off the messy and excess prepreg that is higher than the lower end of the joint, remove the pre-evacuated bag, lay the peelable cloth, lay the isolation film, wrap the upper end of the joint with an appropriate amount of raw silica gel, and then lay the breathable felt, vacuum bag film, place the vacuum nozzle, and vacuumize to shape; 7) Curing: After bag making is completed, it is transferred to the autoclave, the vacuum bag is evacuated with negative pressure, the autoclave is filled with positive pressure, and the final curing process is carried out according to the curing parameters of the prepreg until it is out of the can; 8) Demolding: Remove the vacuum bag, dismantle the mold, and obtain an integrally molded composite material mouth cover with two internal and external thread conversion joints.

2. A composite material cover forming method for tightness test according to claim 1, characterized in that: The step 5) specifically includes: 5-1) Lay 15 layers of cut carbon fiber prepreg sheets on the mold, lay non-porous isolation film, breathable felt, and vacuum bag film on the surface, connect the vacuum nozzle, and evacuate; 5-2) Open the vacuum bag, locate the two joints at a certain distance on the center line of the length direction of the carbon fiber prepreg, make a cross-shaped cut, place the embedded parts from bottom to top, and then continue to lay fifteen layers of carbon fiber prepreg, make a cut at the joint and wrap the embedded parts, seal the pre-vacuum bag, and continue to vacuum.

3. The composite material cover molding method for tightness test according to claim 1, characterized in that: The sand blasting parameters of the sand blasting treatment in step 3) are 100 mesh quartz sand, wind pressure: 0.6~0.8MPa, the inclination between the sand blasting nozzle and the sand blasted surface is 30°~60°, the distance between the sand blasting nozzle and the joint is 150mm~300mm, and the translation speed of the sand blasting nozzle is 0.5~1m / min; the joint after sand blasting needs to be affixed with adhesive film within 6 hours.

4. A composite material mouth cover for tightness test, characterized in that: It includes a mouth cover body, on which a quick-connection air valve and a pressure gauge are arranged; the mouth cover body is provided with two internal and external thread conversion joints, the upper ends of the two internal and external conversion joints are respectively connected to the quick-connection air valve and the pressure gauge, and the lower ends are communicated with the closed space of the hull; the mouth cover body transmits gas to the closed space of the hull through the air inlet and outlet channels in the quick-connection air valve.

5. The composite material mouth cover for tightness test according to claim 4, characterized in that: The quick-plug connector gas valve is provided with inlet and outlet gas channels, and the inlet and outlet gas channels are used for gas transmission; the quick-plug connector gas valve controls the opening and closing of the inlet and outlet gas channels.

6. The composite material mouth cover for tightness test according to claim 4, characterized in that: The quick-plug connector air valve and the pressure gauge are placed at intervals.

7. The composite material mouth cover for tightness test according to claim 4, characterized in that: The quick-connect joint air valve is threadedly connected to the mouth cover body; the pressure gauge is threadedly connected to the mouth cover body.

8. The composite material mouth cover for tightness test according to claim 4, characterized in that: The upper end of the quick-plug joint air valve is connected with an air pipe.

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