CN104742382A - Pressure-assisted VARI (vacuum assisted resin infusion) forming device and method - Google Patents

Abstract

The invention provides a pressure-assisted VARI forming device and method, which relates to a device for assisting VARI forming with external pressure. The pressure-assisted VARI molding device includes molding upper and lower molds, upper and lower mold fixing devices, pressurizing devices, vacuum pumps and resin injection devices. The invention solves the problem that existing VARI shaped products cannot meet the structural requirements of high-performance composite materials because of insufficient vacuum pressure, resulting in relatively low fiber volume content of composite materials, defects such as pores and dry spots in the products. The invention utilizes the advantages of pressurization and solidification in an autoclave, makes up for the deficiency of vacuum pressurization in VARI forming, maximizes strengths and circumvents weaknesses, and furthermore can give full play to the advantages of VARI technology in reducing the manufacturing cost of composite materials and integrally forming large components.

Description

A pressure-assisted vacuum infusion process molding device and method

technical field

The invention relates to a device and a method for forming with an external pressure-assisted vacuum infusion process, and belongs to the technical field of composite material forming.

Background technique

Because advanced composite materials have many advantages such as high specific strength and specific modulus, excellent designability and good fatigue resistance, they have been widely used in aerospace, fan blades, transportation, construction, sporting goods and electromechanical industries. . In the field of aerospace, advanced composite materials can reduce the overall weight of the aircraft structure and improve the overall performance of the aircraft. The amount of composite materials has become an important indicator to measure the advanced nature of aircraft. These provide a broad stage for the display of various new materials and new processes, but the most prominent problem faced by composite materials is the high cost, which limits the further expansion of the application of resin-based composite materials to a certain extent.

Vacuum-assisted resin infusion molding process (vacuum infusion process, hereinafter referred to as VARI) has gradually become a new method for preparing large-size, large-thickness complex parts due to its advantages of low cost, high quality, and flexible process methods. It is a molding method that uses the flow and penetration of resin to impregnate fibers and their fabrics under vacuum conditions and solidify them under vacuum. This process has been successfully used in civilian applications such as ships, military facilities, national defense projects, aviation and wind power. industrial field. However, due to insufficient vacuum pressure, the existing VARI molded products result in relatively low fiber volume content of the composite material, and there are defects such as pores and dry spots in the product, which cannot meet the structural requirements of high-performance composite materials. Therefore, the development and construction of new composite material forming process methods undoubtedly play an important role in the development of composite materials.

Contents of the invention

The technical problem to be solved by the invention is to carry out pressure-assisted VARI molding to meet the requirements of low cost and high performance for composite material molding.

In order to solve the above technical problems, a technical solution of the present invention is to provide a pressure-assisted vacuum infusion process molding device, which is characterized in that it includes an openable upper mold and a lower mold, and the upper mold is provided with a The pressure injection port of the entire upper mold, the vacuum infusion process molding parts are located in the cavity of the lower mold, and the parts of the lower mold located on both sides of the cavity are respectively provided with a resin injection port and a vacuum port communicating with the cavity of the lower mold. , the pressure injection port is connected with the pressurizing device, the resin injection port is connected with the resin system, and the vacuum port is connected with the vacuum pump through the resin collector.

Preferably, the upper mold and the lower mold are respectively fixed on respective fixing devices, and sealing strips for ensuring the airtightness of the upper mold or the airtightness of the lower mold are provided at the fixing devices.

Preferably, the fixing device is a bolt, and bolt holes for fixing bolts are correspondingly and equidistantly reserved around the upper mold or the lower mold.

Preferably, the composite material part is located in the center of the lower mold cavity, and the vacuum infusion process forming part includes a release cloth and a vacuum bag film laid from bottom to top, and the flow medium is located between the release cloth and the vacuum bag film. between one.

Preferably, the edges of the vacuum bag film are glued to the lower mold by sealing glue.

Preferably, a layer of vacuum bag film 2 is laid on the outside of the vacuum infusion process forming device.

Another technical solution of the present invention is to provide a pressure-assisted vacuum infusion process forming method based on the above-mentioned pressure-assisted vacuum infusion process forming device, which is characterized in that a composite material part is placed in the center of the cavity of the lower mold, and then Lay a complete set of vacuum infusion process molding parts. After the upper mold and the lower mold are closed, the vacuum is drawn through the vacuum port, and the resin is injected through the resin injection port. After the resin infusion is completed, the pressurizing device pressurizes through the pressure injection port. until the composite is cured.

Preferably, it specifically includes the following steps:

Step 1. Spray the release agent in the center of the lower mold cavity, place the cut carbon fiber cloth on the position coated with the release agent, and lay the release cloth and flow medium, and stick the sealant around the carbon fiber cloth , and then lay the vacuum bag film 1 to form a vacuum infusion process molding part, reserve a vacuum port and a resin injection port, check and ensure the airtightness of the vacuum infusion process molding part, and then lay it on the upper mold and the lower mold Sealing strips, closing the upper mold and the lower mold and fixing them with fixtures;

Step 2. Use a vacuum pump to evacuate the parts formed by the vacuum infusion process in the lower mold, hold the pressure for a period of time, and detect the degree of vacuum;

Step 3. After the vacuum reaches the standard, pour resin from the resin injection port until the resin fills the entire carbon fiber cloth;

Step 4. After the resin is poured in, the pressurizing device pressurizes through the pressure injection port until the resin is solidified to form a composite material part.

The advantages of the present invention are: compared with the existing VARI forming method, the present invention adds a pressure auxiliary device, its fiber volume content will be significantly increased, and defects such as pores will be significantly reduced; compared with the existing autoclave forming method Compared with this method, the present invention does not require high investment in hot pressing equipment, and the molding process is relatively simple, which can greatly reduce the cost of composite material molding. The performance of the completed composite material component is obviously improved, the cost is significantly reduced, and the composite material has broad application prospects.

Description of drawings

Fig. 1 is the schematic diagram of pressure-assisted VARI forming device of the present invention;

Fig. 2 is a structural schematic diagram of an integral molding die;

Fig. 3 is a schematic diagram of VARI molding in the lower mold;

Among them, 1. Upper mold 2. Lower mold 3. Pressure injection port 4. Resin injection port 5. Vacuum port 6. Upper and lower mold fixing devices 7. Resin system 8. Pressurizing device 9. Resin collector 10. Vacuum pump 11. Composite part 12. Release cloth 13. Flow medium 14. Vacuum bag film 15. Vacuum bag film 16. Sealant.

Detailed ways

In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

Please refer to FIG. 1 , which is a schematic diagram of a pressure-assisted VARI forming device of the present invention. The pressure-assisted VARI molding device includes an upper mold 1, a lower mold 2, a pressure injection port 3, a resin injection port 4, a vacuum port 5, and a fixing device 6 of the upper and lower molds, wherein the fixing devices 6 of the upper and lower molds are sealed strips and fastened with equally spaced bolts.

Please refer to FIG. 2 , which is a structural schematic view of the integral molding die of the present invention. The integral forming mold includes a resin system 7, a pressurizing device 8, a resin collector 9 and a vacuum pump 10, wherein the resin system 7 is connected with the resin injection port 4, the pressurizing device 8 is connected with the pressure injection port 3, and the resin collector 9 It is connected to the vacuum port 5 and connected to the vacuum pump 10.

Please refer to FIG. 3 , which is a schematic diagram of VARI forming in the lower mold 2 of the present invention. The VARI forming schematic diagram includes a composite material part 11 , a release cloth 12 , a flow medium 13 , a vacuum bag film one 14 , a vacuum bag film two 15 , and a sealant 16 .

The composite material part is subjected to VARI molding in the lower mold 2, and the pressure curing of the VARI molding is realized through the pressing device 8 in the upper mold 1. The specific steps are as follows:

Step 1, providing a forming mold including a sealing strip, a fixing device 6, and a suitable shape and size;

Step 2. Spray the release agent on the center of the lower mold 2, lay the cut carbon fiber cloth on the position coated with the release agent, and lay the release cloth 12, the flow medium 13, and stick the sealant 16 around the carbon fiber cloth, Lay vacuum bag film one 14 and vacuum bag film two 15 afterwards, reserve vacuum port 5 and resin injection port 4, check and ensure the airtightness of the device; then lay sealant on upper mold 1 and lower mold 2 strip, close the upper mold 1, the lower mold 2 and fix it with the fixture 6.

Step 3, vacuumize the VARI device in the lower mold 2 with a vacuum pump 10, keep the pressure for a period of time, and check the degree of vacuum.

Step 4: After the vacuum reaches the standard, pour resin from the resin injection port 4 until the resin fills the entire carbon fiber cloth.

Step 5 After the resin is poured in, apply pressure from the pressure injection port 3.

Step 6 Cures the resin to form the composite part.

Claims (8)

1. A pressure-assisted vacuum infusion process molding device is characterized in that it comprises an openable upper mold (1) and a lower mold (2), and the upper mold (1) is provided with a height direction that runs through the entire upper mold ( 1) The pressure injection port (3), the vacuum infusion process molding part is located in the cavity of the lower mold (2), and the cavity of the lower mold (2) is respectively opened on the part of the lower mold (2) located on both sides of the cavity Connected resin injection port (4) and vacuum port (5), wherein, the pressure injection port (3) is connected with the pressurizing device (8), the resin injection port (4) is connected with the resin system (7), and the pumping The vacuum port (5) communicates with the vacuum pump (10) through the resin collector (9). 2. The pressure-assisted vacuum infusion process molding device according to claim 1, characterized in that: the upper mold (1) and the lower mold (2) are respectively fixed on respective fixing devices (6), and the fixing device ( 6) are provided with sealing strips for ensuring the airtightness of the upper mold (1) or the airtightness of the lower mold (2). 3. The pressure-assisted vacuum infusion process forming device according to claim 2, characterized in that: the fixing device (6) is a bolt, and is respectively mounted around the upper mold (1) or the lower mold (2). Correspondingly equidistantly reserve bolt holes for fixing bolts. 4. The pressure-assisted vacuum infusion process forming device according to claim 1, characterized in that: the composite material part (11) is located in the center of the cavity of the lower mold (2), and the vacuum infusion process forming part includes And the release cloth (12) and the vacuum bag film one (14) laid on top, the flow medium (13) is positioned between the release cloth (12) and the vacuum bag film one (14). 5. The pressure-assisted vacuum infusion molding device according to claim 4, characterized in that: the edge of the vacuum bag film (14) is glued to the lower mold (2) by a sealant (16). 6. The pressure-assisted vacuum infusion process forming device according to claim 1, characterized in that: a layer of vacuum bag film two (15) is laid outside the vacuum infusion process forming device. 7. A pressure-assisted vacuum infusion process forming method based on the pressure-assisted vacuum infusion process forming device according to claim 1, characterized in that a composite material part (11) is placed in the center of the cavity of the lower mold (2) , and then lay a complete set of vacuum infusion process molding parts. After the upper mold (1) and the lower mold (2) are closed, the vacuum is drawn through the vacuum port (5), and the resin is injected through the resin injection port (4). After the resin infusion is completed, the pressurizing device (8) pressurizes through the pressure injection port (3) until the composite material is solidified. 8. The pressure-assisted vacuum infusion process forming method according to claim 7, characterized in that it specifically comprises the following steps: Step 1. Spray a release agent in the center of the cavity of the lower mold (2), place the cut carbon fiber cloth on the position coated with the release agent, and lay the release cloth (12) and flow medium (13) , stick a sealant around the carbon fiber cloth, and then lay a vacuum bag film 1 (14) to form a vacuum infusion process molding part, reserve a vacuum port and a resin injection port, and check and ensure the airtightness of the vacuum infusion process molding part , then, lay sealant strips on upper mold (1) and lower mold (2), close upper mold (1) and lower mold (2) and fix it with fixture (6); Step 2. Use a vacuum pump (10) to evacuate the molded parts of the vacuum infusion process in the lower mold (2), hold the pressure for a period of time, and detect the degree of vacuum; Step 3. After the vacuum reaches the standard, pour resin from the resin injection port (4) until the resin fills the entire carbon fiber cloth; Step 4. After the resin is poured in, the pressurizing device (8) pressurizes through the pressure injection port (3) until the resin is solidified to form a composite material part.