Flexible heating and pressurizing device and method based on graphene film

Abstract

The invention belongs to the technical field of design and manufacturing of flexible heating and pressurizing process equipment, and relates to a flexible heating and pressurizing device and method based on a graphene film, the device comprises a console, a clamping mechanism, a paddle root positioning structure, a heating and pressurizing mold and a console integrated control system, and the whole heating and pressurizing process flow is automatically controlled; the heating and pressurizing mold is arranged on a table board, a groove is formed in the heating and pressurizing mold, the front edge of the helicopter main blade is arranged in the groove after being combined with the anti-icing and deicing cementing assembly, the rear edge of the helicopter main blade is clamped and fixed through the clamping mechanism, and the root of the helicopter main blade is positioned and fixed through the blade root positioning structure; a graphene heating film and a silica gel air bag are also arranged in the groove; the graphene heating film is laid on the surface of the anti-icing and deicing cementing assembly, and the space between the graphene heating film and the inner wall of the groove is filled with a silica gel air bag. In the curing forming process of the paddle anti-icing and deicing cementing assembly, firstly, the air bag is used for pressurization and attached to the surface of the paddle anti-icing and deicing cementing assembly in a shape-following mode, so that it is guaranteed that all areas are evenly pressurized, and the borne pressure is consistent; in the pressurizing process, the flexible shape following characteristic of the graphene electric heating film is ingeniously utilized, the graphene electric heating film is attached to the surface of the blade anti-icing and deicing cementing assembly in a shape following mode all the time, the pressurizing process and the heating process can be carried out at the same time, the device can adapt to the difference of the appearance of the blade anti-icing and deicing cementing assembly caused by manufacturing, and the device is especially suitable for mass production and manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible heating and pressurizing process equipment design and manufacturing, and relates to a flexible heating and pressurizing device and method based on a graphene film. Background Art

[0002] For helicopter blades, the leading edge surface needs to be bonded with metal for protection to prevent the composite leading edge skin from being damaged by foreign objects when the blades rotate at high speed. The anti-icing adhesive assembly is a unique blade leading edge protection assembly for helicopters. It needs to be bonded to the cured blades at 0.12Mpa under 60°C. At this time, the anti-icing adhesive assembly and the blades are both rigid bodies, which belongs to the "hard-hard" molding method in composite materials. Because the appearance of the anti-icing adhesive assembly and the blade bonding area cannot be completely matched, conventional rigid pressurization is likely to cause interference and overpressure in some parts of the bonding area, and non-contact and underpressure in some parts, resulting in insufficient glue relay between the anti-icing adhesive assembly and the blade, and the quality problem of debonding of the anti-icing adhesive assembly is prone to occur. The currently known bonding method in China uses a special hot oil bag to bond the anti-icing adhesive assembly, and maintains the pressurization pressure and bonding temperature by circulating hot oil injection, which can be used for bonding anti-icing adhesive assemblies and blades. This method has the problems of high difficulty in manufacturing the hot oil bladder, short service life due to corrosion of the hot oil by the hot oil, and high cost caused by the need for a dedicated mold temperature controller.

[0003] Graphene is a new high-tech material that has emerged in recent years. Graphene can be seen as a two-dimensional six-ring crystal structure with a thickness of only one atomic size formed by one-dimensional carbon nanotubes. It is an ultra-light material with many excellent properties, such as high mechanical strength (Young's modulus up to 1TPa), good electrical conductivity (resistivity only 106Ω*cm), thermal conductivity (thermal conductivity up to 5300W / m*K), high saturation current density (can withstand a current of 100-200 million A / cm2) and large specific surface area (theoretically up to 2630m2 / g). Graphene has good application prospects in many fields such as materials science, micro-nano processing, energy, biomedicine and drug delivery, and is considered to be a revolutionary material in the future. Nowadays, graphene electric heating film has begun to be widely used in various fields. Graphene heating film has a very high electric heat conversion rate. The heating film made of graphene has the advantages of fast heating, fast heat dissipation and good stability.

[0004] Silicone rubber is a commonly used polymer material with stable chemical properties and high mechanical strength. As an auxiliary material for composite material molding, silicone rubber has good processability. It also has the advantages of strong plasticity, good heat resistance, and reusability. The pressurization process of silicone rubber is stable and easy to operate, which can improve the molding quality of parts. A series of studies have been carried out at home and abroad on the design and pressure control of silicone rubber pressurization process. Silicone rubber is widely used as an important auxiliary pressurization material for traditional autoclaves and compression molding. There are two uses for silicone rubber auxiliary molding: one is direct thermal expansion pressurization, which uses the thermal expansion of silicone rubber itself in a closed space to generate pressure on the product; the other is pressure transmission, where the pressure from the outside is transmitted to the surface of the product through silicone rubber.

[0005] In the field of composite material bonding manufacturing, the current heating and pressurization is mainly based on autoclave molding. This technology mainly relies on the heat generated by the autoclave to heat the composite material bonding product. Autoclaves are widely used in the production of aerospace parts and composite material bonding. However, the autoclave has very high requirements on size, temperature, and pressure. Its auxiliary equipment, such as air or ammonia pipelines, cooling pipelines, heating furnaces, and monitoring equipment will also increase its cost, so its manufacturing cost is quite expensive. In addition, the autoclave also has the disadvantages of high energy consumption, large gas consumption, large floor space, and long curing cycle when used. In addition, the heating and pressurization methods of large-sized autoclaves cause slow temperature and pressure response and poor temperature control accuracy. Summary of the invention

[0006] The present invention is based on a flexible and bendable graphene electric heating film and an inflatable silicone airbag, selects corresponding PLC modules, combines upper computer programming technology, compiles a set of control programs to realize the automatic control of airbag stamping, automatic control of process equipment movement and monitoring of process equipment operation status, designs and manufactures low-cost, high-efficiency and automatically controlled flexible heating and pressurizing tooling, breaking the high-cost and high-energy consumption technical barriers of current autoclave equipment for composite material bonding molding.

[0007] Technical solution: In order to achieve the above-mentioned purpose, a flexible heating and pressurizing device based on graphene film is provided, including a control panel, a clamping mechanism, a blade root positioning structure, a heating and pressurizing mold, and a control panel integrated control system to automatically control the entire heating and pressurizing process; the heating and pressurizing mold is arranged on a table, and a groove is opened on the heating and pressurizing mold. The leading edge of the helicopter main blade is combined with the anti-icing adhesive component and placed in the groove, and the trailing edge of the helicopter main blade is clamped and fixed by the clamping mechanism, and the blade root of the helicopter main blade is positioned and fixed by the blade root positioning structure; a graphene heating film and a silicone airbag are also arranged in the groove; the graphene heating film is laid on the surface of the anti-icing adhesive component, and the silicone airbag is filled between the graphene heating film and the inner wall of the groove.

[0008] Furthermore, the graphene electric heating film comprises a graphene film, a copper foil electrode and two layers of TPU hot-melt protective film. The specific structure from top to bottom is TPU hot-melt protective film + copper foil electrode + graphene film + TPU hot-melt protective film. The graphene heating film is formed by hot pressing composite molding.

[0009] Furthermore, the copper foil electrode is externally connected to a temperature controller including a PID control module, and the temperature controller is externally connected to a 24V plug.

[0010] Furthermore, the silicone airbag is formed by heating and curing two layers of silicone sheets in a special mold, and two air nozzles are embedded in the molding process. The silicone airbag is a pressurizing device of the process equipment.

[0011] Furthermore, the control system is integrated with an automatic control program, adopts a host computer programming technology, and the operating system is a host computer operation interface based on an industrial computer, which can realize a human-computer interaction interface.

[0012] Furthermore, the control system hardware uses electrical components such as a host computer, a PLC control module, an industrial computer, and a thermocouple, and is integrated with the software system. The above-mentioned automatic control program is the control core of the process equipment, which controls the power of the graphene heating film to adjust the temperature, and controls the relative motion relationship of each system through control system instructions.

[0013] Furthermore, the control system can realize automatic adjustment function by controlling the inflation and deflation modules, and issue early warning for situations where the pressure is too high or too low; a distributed temperature sensor is embedded between the graphene heating film and the anti-icing component. The temperature sensor can collect the temperature distribution of the anti-icing component, and through multi-point distributed measurement, the overall balance of the heating temperature can be accurately controlled.

[0014] Furthermore, the heating and pressurizing mold is arranged on a guide rail to facilitate adjusting the position of the main rotor blade of the helicopter.

[0015] The present invention also proposes a flexible heating and pressurizing method based on graphene film, using the heating and pressurizing device designed as above, and the specific method process is as follows:

[0016] Blade installation: install the anti-icing system and helicopter main blades into the heated and pressurized mold in sequence;

[0017] Blade positioning: Position the blade root bushing and blade tip counterweight box separately;

[0018] The clamping mechanism works: the motor drives the clamping mechanism to reach the theoretical position and clamps the blades;

[0019] Airbag pressurization: add a certain amount of air into the silicone airbag through the air pressure control system;

[0020] Heating and curing: The graphene electric heating film is started by the electric heating system, and heated and cured according to the set heating curve;

[0021] Blade disassembly: After curing is completed, return each subassembly and system to their original position; pull out the locating pin of the bushing hole at the blade root and take out the blade.

[0022] Technical effect: The advantages of the present invention are:

[0023] 1. The present invention uses the graphene electric heating film which is a shelf product and the silicone airbag which is easy to manufacture, combined with the automatic control system, to realize the flexible heating and pressurization of the heating components of the helicopter composite blades and the iron-clad adhesive forming.

[0024] 2. During the curing and molding process of the blade anti-icing adhesive assembly of the present invention, the airbag is firstly used to apply pressure and adhere to the surface of the blade anti-icing adhesive assembly in a conformal manner to ensure that each area is evenly pressurized and the pressure is consistent; during the pressurization process, the flexible conformal characteristics of the graphene electric heating film are cleverly utilized to always adhere to the surface of the blade anti-icing adhesive assembly in a conformal manner, and the pressurization and heating processes can be carried out simultaneously, and the airbag can adapt to the differences in the appearance of the blade anti-icing adhesive assembly caused by manufacturing, which is particularly suitable for mass production.

[0025] 3. Compared with the existing heating and pressurizing technology, the present invention has the advantages of low cost, simple application and quick manufacturing.

[0026] 4. The automated control system used in the present invention can realize automated control of process equipment, and has the advantages of high automation and easy operation compared with the existing flexible heating and pressurizing technology.

[0027] 5. Compared with the existing equipment with the same function, the helicopter blade anti-icing system bonding process equipment used in the present invention reduces the peak power of the heating system from 75Kw to 10Kw, reduces the electric heating system, hydraulic system, and voltage stabilization system of the process equipment, and replaces the special oil-resistant silicone capsule with an ordinary silicone airbag. The total cost of the process equipment is reduced by more than 1.1 million yuan, and the energy consumption cost of a single helicopter main blade anti-icing system bonding is saved by 5,000 yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A specific structural form of the helicopter main blade anti-icing system bonding process equipment using the present invention;

[0029] In the figure, 1-helicopter main blade, 2-control console, 3-clamping mechanism, 4-blade root positioning structure, 5-guide rail, 6-servo motor;

[0030] Figure 2 This is a schematic diagram of the specific structure of the graphene heating film;

[0031] In the figure, 7-TPU hot melt protective film, 8-graphene film, 9-copper foil electrode;

[0032] Figure 3 This is a schematic diagram of the silicone airbag structure;

[0033] In the figure, 10-double-layer silicon capsule, 11-air nozzle;

[0034] Figure 4 This is a schematic diagram of flexible heating and pressurization;

[0035] In the figure, 12-blade anti-icing assembly, 13-main blade;

[0036] Figure 5 This is a schematic diagram of flexible heating and pressurization;

[0037] Among them, 14-pressure flow, thermal flow schematic, 15-graphene heating film;

[0038] Figure 6 It is a schematic diagram of the air pressure control system;

[0039] In the figure, 16 is a two-position three-way solenoid valve, 17 is a three-piece with a pressure reducing valve, 18 is a pressure sensor, 19 is a two-position three-way solenoid valve, 20 is a pressure sensor, 21 is a two-position two-way solenoid valve, and 22 is a single-phase valve. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0041] The flexible heating and pressurizing scheme of graphene film proposed in the present invention has been applied to the research and trial production of a certain type of helicopter blades. Figures 1 to 6 The content is the application of the present invention in the bonding process equipment of the helicopter main blade anti-icing system. The function is to heat and pressurize the iron-clad bonding part after the leading edge of the blade is bonded with the iron-clad adhesive. The system needs to provide a working temperature of 60℃±10℃ and a working pressure of 0.12MPa during the curing process of the blade and the iron-clad adhesive.

[0042] The flexible heating and pressurizing device of the graphene film comprises:

[0043] 1) Process equipment mechanical system;

[0044] 2) Electrical system of process equipment.

[0045] The mechanical system mainly includes: process equipment frame assembly, propeller root positioning structure, silicone airbag assembly and anti-icing system support assembly (using heated and pressurized mold). The electrical system mainly includes: guide rail system, servo motor, electric heating system, airbag inflation system and control console.

[0046] The specific structural form of the helicopter main blade anti-icing system bonding process equipment using the present invention is as follows Figure 1 , which consists of control panel 2, clamping mechanism 3, blade root positioning structure 4, guide rail 5, servo motor 6 and other parts. The heating and pressurizing mold is placed on the guide rail 5. The graphene heating film is soft and can fit tightly with the heated object. The outer contour of the leading edge iron package of the blade has an irregular attack angle. The graphene heating film has the advantage of strong flexibility and can completely wrap the leading edge of the blade and the iron package to meet the heating requirements. The graphene heating film structure is as follows Figure 2 As shown, it is formed by hot pressing and compounding of double-layer 7-TPU hot-melt protective film, 8-graphene film, and 9-copper foil electrode. The graphene heating film is installed between 1-helicopter main blade and 3-clamping mechanism, and the graphene heating film ear is installed on 3-clamping mechanism through thumbtacks. The blade is long and irregular in shape. It is very easy to cause stress imbalance when applying unit force load. The airbag has the characteristic of equalizing pressure. In order to ensure that each part of the blade surface reaches the same load condition, the airbag is used to wrap and pressurize. The structure of the silicone airbag is as follows Figure 4 As shown, it is made of two layers of 1453D raw silicone sheets bonded together using a molding mold, two air nozzles 11 are embedded in the double-layer silicone capsule 10, and the silicone airbag is installed in the heating and pressurizing mold, and the surface is covered with a layer of canvas. Figure 4 , 5 As shown, the air pressure control system controls the air source of the plant, reduces the pressure of the gas to a working pressure of 0.12Mpa through the basic components of the pressure reducing valve and the solenoid valve, and injects it into the silicone airbag. The pressure flow 14 and the heat flow are transmitted to the anti-icing system through the graphene heating film 15. Figure 6As shown, it is composed of a two-position three-way solenoid valve 16, a three-way body 17 with a pressure reducing valve, a pressure sensor 18, a two-position three-way solenoid valve 19, a pressure sensor 20, a two-position two-way solenoid valve 21, a single-phase valve 22, etc. When the main switch button of the gas source is pressed, the two-position three-way solenoid valve 16 opens, and the gas source pressure is 0.6Mpa at this time. After the gas source enters the three-way body 17 with a pressure reducing valve, the pressure output through the pressure reducing valve is 0.12Mpa. When the pressure sensor 18 detects that the pressure is 0.12Mpa, the program controls the two-position three-way solenoid valve 19 to open, and the gas enters the airbag through the single-phase valve 22. The gas can only flow in one direction toward the air inlet of the airbag. The single-phase valve 22 is connected to a three-way pipe, and the pressure of the airbag is detected by the pressure sensor 20. If the pressure is less than 0.12Mpa, the program controls the two-position three-way solenoid valve 19 to continue to inlet. When the pressure sensor 20 detects that the gas source pressure is greater than 0.12Mpa, the program controls the two-position three-way solenoid valve 19 to close and the two-position two-way solenoid valve 21 to open to discharge gas to the outside. The pressure in the airbag is always maintained at 0.12Mpa. The system is equipped with a relief valve. When the pressure exceeds 0.13Mpa, the relief valve automatically turns on the overflow protection function.

[0047] The control system can realize automatic adjustment function by controlling the inflation and deflation modules, and give early warning for situations where the pressure is too high or too low. A distributed temperature sensor is embedded between the graphene heating film and the anti-icing component. The temperature sensor can collect the temperature distribution of the anti-icing component. Through multi-point distributed measurement, the overall balance of the heating temperature can be accurately controlled. The control system includes a host computer, an operating table and a PLC control cabinet, a low-voltage temperature control system, distributed temperature sensors, pressure sensors, position encoders and other on-site detection devices to achieve automatic control of the entire process. The system also has measurement display and interlocking control functions, and the working process is clear at a glance. After heating and pressurizing to the set value and time, the system automatically connects to the printer to print the temperature and pressure curves and saves the curves to the computer disk.

[0048] The workflow is as follows:

[0049] Blade installation: Manually install the anti-icing system and blades into the heated and pressurized mold in sequence;

[0050] Blade positioning: Position the blade root bushing and blade tip counterweight box separately;

[0051] The clamping mechanism works: the motor drives the clamping mechanism to reach the theoretical position and clamps the blades;

[0052] Airbag pressurization: 0.12Mpa air is added to the airbag through the air pressure control system;

[0053] Heating and curing: heating and curing according to the set heating curve through the electric heating system;

[0054] Blade disassembly: After curing, return all subassemblies and systems to their original positions. Pull out the locating pins from the bushing holes at the propeller root and remove the blades.

[0055] The above specific implementation methods or cases are only used to explain the technical solutions of the present invention, and are not intended to limit the present invention. Any parts not described in detail are regarded as conventional technical means in the art. A person of ordinary skill in the art should understand that based on the design concept of the present application, the technical solutions described in the aforementioned implementation methods should be adaptively modified, or some or all of the technical features therein should be replaced by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible heating and pressurizing device based on graphene film, characterized in that: It includes a control panel, a clamping mechanism, a blade root positioning structure, a heating and pressurizing mold, and an integrated control system of the control panel to automatically control the entire heating and pressurizing process; the heating and pressurizing mold is arranged on a table, and a groove is opened on the heating and pressurizing mold. The leading edge of the helicopter main blade is combined with the anti-icing adhesive component and placed in the groove, and the trailing edge of the helicopter main blade is clamped and fixed by the clamping mechanism, and the blade root of the helicopter main blade is positioned and fixed by the blade root positioning structure; a graphene heating film and a silicone airbag are also arranged in the groove; the graphene heating film is laid on the surface of the anti-icing adhesive component, and the silicone airbag is filled between the graphene heating film and the inner wall of the groove.

2. A flexible heating and pressurizing device based on graphene film as claimed in claim 1, characterized in that: The graphene electric heating film comprises a graphene film, a copper foil electrode and two layers of TPU hot-melt protective film. The specific structure from top to bottom is TPU hot-melt protective film + copper foil electrode + graphene film + TPU hot-melt protective film. The graphene heating film is formed by hot pressing composite molding.

3. A flexible heating and pressurizing device based on graphene film as claimed in claim 2, characterized in that: The copper foil electrode is externally connected to a temperature controller including a PID control module, and the temperature controller is externally connected to a 24V plug.

4. A flexible heating and pressurizing device based on graphene film as claimed in claim 1, characterized in that: The silicone airbag is formed by heating and curing two layers of silicone sheets in a special mold, and two air nozzles are embedded in the molding process.

5. A flexible heating and pressurizing device based on graphene film as claimed in claim 1, characterized in that: The control system integrates an automated control program and adopts host computer programming technology. The operating system is a host computer operation interface based on an industrial computer, which can realize a human-computer interaction interface.

6. A flexible heating and pressurizing device based on graphene film as claimed in claim 5, characterized in that: The control system hardware uses electrical components such as host computers, PLC control modules, industrial computers, and thermocouples, which are integrated with the software system.

7. A flexible heating and pressurizing device based on graphene film as claimed in claim 1, characterized in that: The control system realizes automatic adjustment function by controlling the inflation and deflation modules, and issues early warning for situations where the pressure is too high or too low. A distributed temperature sensor is embedded between the graphene heating film and the anti-icing component. The temperature sensor collects the temperature distribution of the anti-icing component and performs multi-point distributed measurement to accurately control the overall balance of the heating temperature.

8. The flexible heating and pressurizing device based on graphene film according to claim 1, characterized in that: The heating and pressurizing mold is arranged on a guide slide rail to facilitate the adjustment of the position of the helicopter main rotor blade.

9. A flexible heating and pressurizing method based on graphene film, using the heating and pressurizing device according to any one of claims 1 to 8, characterized in that: The specific method process is as follows: Blade installation: install the anti-icing system and helicopter main blades into the heated and pressurized mold in sequence; Blade positioning: Position the blade root bushing and blade tip counterweight box separately; The clamping mechanism works: the motor drives the clamping mechanism to reach the theoretical position and clamps the blades; Airbag pressurization: add a certain amount of air into the silicone airbag through the air pressure control system; Heating and curing: The graphene electric heating film is started by the electric heating system, and heated and cured according to the set heating curve; Blade disassembly: After curing is completed, return each subassembly and system to their original position; pull out the locating pin of the bushing hole at the blade root and take out the blade.

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