KR102312636B1 - Tube type high speed molding device - Google Patents

Abstract

A tubular high-speed molding device according to the present invention comprises: a tubular mold comprising a housing having a space for accommodating heating medium oil therein and open in a lower direction, a flexible membrane positioned in the open lower direction of the housing to block the open lower part, and a horizontal partition for dividing the inside into a first area at the top and a second area at the bottom, wherein, in the housing, an inlet through which the heating medium oil is injected is located at one position, and an outlet through which the heating medium oil is discharged is located at a corresponding position on the other side; a lower mold having a cavity corresponding to the shape of a molded product on the upper surface and engaged with the tubular mold; and a heat medium circulation part for supplying the heating medium oil to the tubular mold at a preset temperature and pressure. Accordingly, it is possible to manufacture high-precision and high-quality molded products with very few voids at a relatively low cost.

Description

Tube-type high-speed molding equipment {TUBE TYPE HIGH SPEED MOLDING DEVICE}

The present invention relates to a high-speed molding apparatus using a carbon fiber composite material, and more particularly, to a high-speed compression molding apparatus using a carbon fiber composite material having an isotropic pressure distribution.

Carbon fiber is a fiber having a molecular chain form with a large number of carbon atoms forming a crystal structure. It is a material with very good mechanical properties because it is very thin, has high tensile strength and rigidity, high heat resistance, and high resistance to chemicals. Since such carbon fiber can achieve high mechanical properties and weight reduction at the same time, it is used in aircraft, automobiles, sports equipment, etc., and is gradually being supplied to various fields. In general, carbon fiber is used to manufacture a target molded article in the form of a prepreg, which is a carbon fiber composite material impregnated with a thermosetting resin and molded, rather than being used by itself.

As molding methods using carbon fiber composite materials, molding methods such as hand lay-up molding, SMC (Sheet Molding Compound) molding, RTM (Resin transfer molding), and autoclave molding are used. . Hand layup molding produces carbon fiber composite materials by alternately laminating carbon fibers and thermosetting resins in a mold. production is difficult. SMC molding and RTM are methods of molding a product by putting a sheet-type carbon fiber composite material into a mold and then applying high temperature/high pressure or injecting resin in a high temperature/high pressure state. It can be produced at high speed, but it is difficult to achieve high precision and high quality, so the properties of the manufactured molded product are poor.

In particular, in SMC molding or RTM molding, since molding proceeds through pressure applied in a specific direction, it is difficult to control the pressure. The direction in which the pressure is applied and the surface of the product are not perpendicular to each other, resulting in non-uniformity throughout the structure, resulting in reduced physical properties of the manufactured product. In addition, RTM technology is continuously developed with VA-RTM (Vacuum Assist-RTM), HP-RTM (High Pressure RTM), C-RTM (Compression RTM), I-RTM (Injection RTM), S-RTM (Surface RTM), etc. Although technological advancement is being made, there is a limit to increasing the carbon fiber content of the carbon fiber composite molded article, and the need to secure resin fluidity according to the shape of the molded article, the difficulty of securing the surface quality of the molded article according to the resin fluidity, and the arrangement of carbon fibers during the injection process It is difficult to maintain, and does not solve the problem of uneven pressure.

Autoclave molding is a process introduced to solve the above-described problems, and is a process of manufacturing a molded article by stacking a prepreg on a mold in multiple layers and then wrapping the whole with a vacuum bag and maintaining an internal vacuum. Autoclave molding uses vacuum to apply pressure in the vertical direction to the surface regardless of the shape of the molded product, thereby achieving isotropic pressure distribution and manufacturing high-precision and high-quality molded products. However, autoclave molding requires a lot of time for the molding process and requires a separate equipment for maintaining the internal vacuum, which requires a very large cost and space.

Korean Patent Publication No. 10-2020-0034046

The present invention is an invention devised to solve the above problems, and an object of the present invention is to provide a molding apparatus capable of high-speed molding while achieving high precision and high quality in molding using a carbon fiber composite material.

These and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

The object is provided with a space for accommodating the thermal oil therein and is composed of a housing having an open downward direction and a flexible membrane positioned in the open downward direction of the housing to block the open lower part, and thermal fluid is injected at one position a tubular mold having an inlet and a discharge port through which the thermal oil is discharged at a position corresponding to the other side, and having a horizontal partition dividing the inside into a first area on the upper side and a second area on the lower side; a lower mold having a cavity (cavity) corresponding to the shape of the molded article formed on the upper surface and engaged with the tubular mold; and a heat medium circulation unit for supplying heat medium oil to the tubular mold at a preset temperature and pressure.

Preferably, in the tubular mold, heat medium oil is first injected and dispersed in the first area located above the horizontal partition, and then the heat medium oil moves to the second area through micro-holes formed in the horizontal partition to expand the flexible film. can

Preferably, the tubular mold may further include two or more partition walls formed on the upper surface of the horizontal partition.

Preferably, one end and the other end of the two or more partition walls are alternately opened to form a flow path so that the thermal oil moves up and down or left and right.

Preferably, the thermal oil injected into the first region is dispersed through the flow path formed by the partition wall located on the upper surface of the horizontal partition, and then moves to the second region through the micro-holes of the horizontal partition to expand the flexible film. it could be

Preferably, the partition wall may have two or more tunnels through which the thermal oil passes.

Preferably, in the tubular high-speed forming apparatus, a carbon fiber prepreg is laminated in the cavity of the lower mold in a state in which the tubular mold and the lower mold are separated, and the tubular mold is meshed on the lower mold, and then heated By injecting the heating medium oil heated through the part into the housing of the tubular mold to expand the flexible film through the pressure of the heating medium oil, while compressing the carbon fiber prepreg on the cavity, the thermal energy of the heating medium oil is transferred to harden the carbon fiber prepreg it could be

Preferably, the heat medium circulation unit may be to discharge the heat medium oil inside the tubular mold by using a fluid pump.

Preferably, the heating medium circulation unit may measure the temperature of the thermal medium inside the tubular mold through a temperature sensor located inside the tubular mold and adjust the temperature of the thermal medium to a preset temperature.

Preferably, the flexible membrane expands by the thermal oil injected into the tubular mold and is in contact with the carbon fiber prepreg located inside the cavity of the lower mold at all positions of the internal shape of the cavity perpendicular to the internal shape of the cavity It may be to transmit the same amount of pressure to the

The tube-type high-speed molding apparatus according to an embodiment of the present invention transfers uniform pressure using a process method of applying heat and pressure to a carbon fiber composite material using a tubular structure and heat medium oil, thereby having a short molding cycle and performing high-speed molding. It is possible to manufacture a high-precision and high-quality molded article with very few voids at a relatively low cost while making it possible.

In addition, the tubular high-speed molding apparatus according to an embodiment of the present invention has a structure for dispersing thermal oil inside the tubular mold, so that the thermal medium can uniformly expand the flexible film to uniformly mold the carbon fiber prepreg.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a block diagram of a tube-type high-speed forming apparatus according to an embodiment of the present invention.
2 is a perspective view of a tubular mold and a lower mold of a tubular high-speed forming apparatus according to an embodiment of the present invention.
3 is a block diagram of a horizontal partition positioned inside the tubular mold of FIG. 1 .
4 is a view for explaining a deformed state during molding of the tubular high-speed molding apparatus according to an embodiment of the present invention.
5 is a view for explaining the isotropic pressure distribution structure of the tubular high-speed forming apparatus according to an embodiment of the present invention.
6 is a flowchart of a tubular high-speed forming method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Terms and words used in this specification are terms selected in consideration of functions in the embodiments, and the meaning of the terms may vary according to the intention or custom of the invention. Therefore, the terms used in the following examples, when specifically defined in the present specification, follow the definition, and when there is no specific definition, it should be interpreted as a meaning generally recognized by those skilled in the art.

1 is a block diagram of a tube-type high-speed forming apparatus according to an embodiment of the present invention.

2 is a perspective view of a tubular mold and a lower mold of a tubular high-speed forming apparatus according to an embodiment of the present invention.

3 is a block diagram of a horizontal partition positioned inside the tubular mold of FIG. 1 .

4 is a view for explaining a deformed state during molding of the tubular high-speed molding apparatus according to an embodiment of the present invention.

1 to 4 , the tubular high-speed molding apparatus according to an embodiment of the present invention includes a mold part composed of a tubular mold 100 and a lower mold 200 , a thermal oil tank 310 and a heating part 320 . It includes a heat medium circulation unit 300 consisting of. In the present invention, the heating medium oil 30 heated through the heating medium circulation unit 300 is injected into the tubular mold 100 to heat and pressurize the carbon fiber prepreg located between the tubular mold 100 and the lower mold 200 . to manufacture a molded article.

The tubular mold 100 includes a housing 110 , a flexible membrane 120 , an air pressurizing unit 130 , and a horizontal partition 140 .

The housing 110 has a space for accommodating the thermal oil 30 therein, and has an open downward direction (lower mold engagement direction). And the flexible membrane 120 is positioned in the open lower direction of the housing 110 and has a structure to block the open lower part.

The housing 110 may have a form in which the lower direction is opened, and a space for accommodating the thermal oil 30 may be provided therein to have a container form in which one direction is opened. At this time, the housing 110 is made of a material having rigidity so as not to be deformed or damaged by the pressure and temperature of the thermal oil 30 injected therein. As an example, the housing 110 may be made of various metal materials such as a nickel alloy, a steel alloy, and an Invar alloy.

An inlet through which the thermal oil 30 is injected from the thermal medium circulation unit 300 is located at one position of the housing 110, and an outlet through which the injected thermal oil 30 is discharged is located at a position corresponding to the other side. The positions of the inlet and outlet are positioned with each other so that heat and pressure can be effectively transferred to the carbon fiber prepreg 10 through the flexible film 120 without interfering with the circulation of the thermal oil 30 injected into the housing 110 . It is preferable to be located in the corresponding direction.

The flexible membrane 120 is located in the open lower direction (lower inlet) of the housing 110 and is fixed on the housing 110 in a form to completely block and block the open lower direction of the housing 110 .

The flexible film 120 is formed of a film of a material having flexibility rather than a rigid material having a fixed shape, and has a structure that expands by the thermal oil injected into the housing 110 . As an example, the flexible film 120 is preferably formed of a silicon material having high thermal conductivity. At this time, the thickness and durability of the flexible film 120 may vary depending on the type and shape of the carbon fiber composite material to be manufactured.

The flexible film 120 has high strength and tear strength characteristics to prevent physical damage and thermal deformation caused by the thermal oil 30 , and effectively transmits the pressure caused by the thermal oil 30 to the carbon fiber prepreg 10 . It is preferable to have a high elongation for this purpose. As an example, the flexible membrane 120 preferably has a shore hardness of 30-40, a tensile strength of 1400-1800 psi, a tear strength of 200 ppi or more, and an elongation of 900%.

The housing 110 of the tubular mold 100 is divided into an upper first area and a lower second area by a horizontal partition 140 . The thermal oil 30 injected into the tubular mold 100 is first injected into the first region above the horizontal partition 140 , and then through the plurality of micro-holes 141 formed in the horizontal partition 140 , the horizontal partition 140 . ) moves to the lower second region to expand the flexible membrane 120 . As described above, in the present invention, the inside of the tubular mold 100 is divided into an upper first area and a lower second area through the horizontal partition 140, and the thermal oil 30 is first injected into the first area and then fine By moving to the second region through the hole 141 to apply heat and pressure to the flexible membrane 120 , the thermal medium oil 30 injected into the tubular mold 100 is injected into the flexible membrane 120 at the same time as heat and pressure are applied to the flexible membrane 120 . By delaying the transfer, the thermal oil 30 evenly transfers heat and pressure throughout the flexible membrane 120 . In this case, the speed at which the thermal oil 30 moves from the first region to the second region may be controlled through the size and number of the micro-holes 141 .

If the thermal medium oil 30 is injected into the tubular mold 100 without the horizontal partition 140 , the injected thermal medium oil 30 directly contacts the flexible membrane 120 immediately after the input to transfer heat and pressure. . When heat and pressure are transferred to the flexible membrane 120 immediately after the injected thermal oil 30 is injected, the flexible membrane 120 expands from the position where the thermal fluid is injected, and heat and pressure are first applied to the carbon fiber prepreg 10 . Since the transfer starts the molding, the carbon fiber prepreg 10 is not uniformly molded. Therefore, in the present invention, the upper first area and the lower second area are separated through the horizontal partition 140 , and the thermal medium oil 30 is first injected into the first area and then the second area is passed through the micro-holes 141 . By moving to, the carbon fiber prepreg 10 is uniformly molded.

The upper surface of the horizontal partition 140 may include two or more partition walls 142 . The partition walls 142 are spaced apart from each other by a predetermined interval, and form a flow path for the thermal oil 30 on the horizontal partition 140 so that the thermal oil is uniformly dispersed in the tubular mold 100 . At this time, the two or more partition walls 142 have one end and the other end open alternately, respectively, so that the thermal oil 30 moves in a zigzag manner through the opened position of the partition wall 142 . When the thermal oil 30 is injected into the inlet of the tubular mold 100 , the thermal oil 30 reaches the outlet before the thermal oil 30 is dispersed inside the tubular mold 100 so that the thermal oil 30 is not evenly distributed Accordingly, in the present invention, by arranging one or more partition walls 142 on the upper surface of the horizontal partition 140 to form a flow path, the thermal oil 30 is evenly distributed inside the tubular mold 100 . As shown in FIG. 3 , the thermal oil 30 injected into the tubular mold 100 moves along the flow path formed by the partition wall 142 , and is uniformly distributed inside the tubular mold 100 . In this case, the number and spacing of the partition walls 142 can be freely designed according to the size of the tubular mold 100 , a molding target, and the like.

In addition, the partition wall 142 is provided with one or more tunnels through which the thermal oil 30 can pass. It can move through and be uniformly dispersed. The shape of the tunnel formed in the partition wall 140 may have various shapes, such as circular, semi-circular, elliptical, and omega-type, and the shape, number, and size of the tunnel can be freely designed according to the design purpose and the object to be formed.

The tubular high-speed molding apparatus according to an embodiment of the present invention injects the thermal medium oil 30 heated to a predetermined temperature by the thermal medium circulation unit 300 into the tubular mold 100 at a predetermined pressure, thereby forming the flexible film 120 ) to expand and mold the carbon fiber prepreg 10 with a predetermined heat and pressure. To this end, a fluid pump 331 is located at a position where the thermal oil 30 is injected into the tubular mold 100 , and pressure valves 341 and 342 are located at the injection and discharge portions of the tubular mold 100 , Control the pressure of the oil (30).

In addition, the tubular high-speed molding apparatus according to an embodiment of the present invention further includes an air pressurizing structure through the air pressurizing unit 130 in addition to the pressurizing structure using the fluid pump 331 . Since the heat medium oil 30 is heated to a high temperature, when the heat medium oil 30 is pressurized using the fluid pump 331 , as the pressure required increases, the fluid pump 331 also requires corresponding durability. In particular, when the high-temperature thermal oil 30 is pressurized, a leak may occur in the fluid pump 331 or a required pressure may not be achieved. Therefore, in the present invention, the heat medium oil pressure inside the tubular mold 100 is increased by transferring additional pressure by adding the air pressurizing part 130 to the tubular mold 100 .

The air pressurization unit 130 includes an air membrane 131 and an air pump 132 . The air membrane 130 is positioned in the upper open space of the housing 110 of the tubular mold 100, and the air membrane 130 expands in the tubular mold interior direction by the pressure of the air supplied from the provided air pump 132 to form a tubular mold. The pressure of the heat medium oil 30 inside the mold 100 is increased. As the air membrane 130 expands in the inner direction of the tubular mold 100 by the air pump 132, the pressure is transferred to the thermal medium oil 30 inside the tubular mold 100, and the flexible membrane 120 is a carbon fiber preprep. Increase the pressure forming leg 10 . As such, in the present invention, a method of expanding the air membrane 130 using the air pump 132 to increase the pressure inside the tubular mold 100 is used. This is to prevent the thermal medium oil 30 from being oxidized, and since the thermal medium oil 30 is oxidized when the high temperature thermal medium oil 30 is in direct contact with air, the thermal medium oil 30 is passed through the air film 131 . ) and the direct contact between the air can be blocked to prevent oxidation of the thermal medium oil (30).

That is, the present invention not only regulates the pressure of the thermal oil 30 inside the tubular mold 100 through the fluid pump 331 , but also supplies additional pressure through the air pressurizing unit 130 to increase the pressure of the thermal oil 30 . can be adjusted Therefore, by distributing the total pressure required for molding to the fluid pump 331 and the air pressurizing unit 130 , fatigue applied to the fluid pump 331 can be reduced, and the high pressure due to the simple structure of the air pressurizing unit 130 . can be achieved, thereby reducing manufacturing costs.

As an example, when the tubular high-speed molding apparatus of the present invention manufactures two or more molded products at the same time, that is, when two or more cavities are formed in the lower mold 200, the individual cavities and the vertical direction to correspond to each cavity 1:1 Two or more air pressurizing units 130 may be disposed at positions corresponding to .

In addition, the air pressurization unit 130 may further include an auxiliary guide. The auxiliary guide is positioned around the air membrane 131 to limit the direction and volume in which the air membrane 131 expands. In the process of expanding the air membrane 131 by the air pump 132 , the air membrane 131 over-expands or pressure in the wrong direction. to prevent the transmission of

The tubular mold 100 may further include a heating structure for maintaining the temperature of the thermal medium 30 during the process in which the injected thermal oil 30 expands the flexible film 120 to form the carbon fiber prepreg 10. can As an example, the heating structure inserted into the tubular mold 100 may use a heater, a heating wire, a cartridge heater, etc., and the shape and structure are not limited. Such a heating structure prevents the temperature of the thermal medium 30 from falling during the process inside the tubular mold 100 and serves to maintain the temperature of the thermal medium 30 at the molding temperature.

The lower mold 200 is a mold engaged with the tubular mold 100 in a downward direction, and has a structure in which a cavity is formed on an upper surface. The cavity of the lower mold 200 is configured in a shape corresponding to the shape of the molded article to be molded. And the carbon fiber prepreg is positioned inside the cavity and is molded by the heat and pressure transferred by the tubular mold 100 .

The lower mold 200 has a rigid structure that is not deformed by an external force, unlike the tubular mold 100 , and may be made of various metal materials such as nickel alloy, steel alloy, and Invar alloy.

In addition, the lower mold 200 may include a heating structure to have the same temperature as the temperature (heat medium oil temperature) of the tubular mold 100 during the molding process. The heating structure of the lower mold 200 may use a heater, a heating wire, a cartridge heater, or the like, or a structure in which the thermal oil passes through a passage through which the thermal oil may pass. At this time, the heating structure of the lower mold 200 is not limited to a structure by a heater, a heating wire, a cartridge heater, or a heat medium oil passing through a flow path, and other structures such as a heater generally used for heating or cooling the mold may be used. can

In addition, the lower mold 200 may further include a cooling structure for cooling the molded article before separating the mold after completion of molding. In this case, the cooling structure of the lower mold 200 may have a structure in which a refrigerant passes through a pipe located inside the lower mold 200 , and in addition, various mechanisms and structures for cooling the mold may be applied.

In the present invention, the tubular mold 100 has a structure in which the flexible film 120 is expanded by the thermal oil 30 injected through the injection hole. As described above, in the state where the tubular mold 100 and the lower mold 200 are engaged, the flexible membrane 120 expands by the thermal oil 30 injected into the housing 110 of the tubular mold 100 while the lower mold ( 200) to transmit the pressure to the carbon fiber prepreg located on the cavity. In addition, since the thermal oil 30 is heated by the thermal medium circulation unit 300, heat is transferred to the carbon fiber prepreg 10 located on the cavity of the lower mold 200 according to the thermal conductivity of the flexible film 120. . In addition, when a higher pressure is required during molding, an additional pressure is transmitted through the air pressure unit 130 to increase the molding pressure. As described above, in the tubular compression molding apparatus according to an embodiment of the present invention, heat and pressure are transferred through the thermal medium oil 30 and the flexible film 120 to form the carbon fiber prepreg 10, which is a carbon fiber prepreg, to form a molded product. to manufacture

As an example of the thermal medium used in the present invention, mineral oil, glycol-based oil, high temperature thermal medium (synthetic paraffin, diaryl alkane, polyphenyl derivative, aryl ether, dimethylsiloxane, etc.) may be used. Mineral oil has an operating temperature of 150~300℃ and can be used for general purposes, and glycol-based oil has a working temperature of -50~180℃, so it can be used for secondary cooling and heating such as container jackets and pipe tracing. Thermal oil for use has a working temperature of 275~375℃, so it can be used in processes that require high temperatures.

As shown in FIG. 1 , the heat medium circulation unit 300 heats the heat medium oil 30 to a predetermined temperature and supplies it to the tubular mold 100 at a predetermined pressure. The heating medium circulation unit 300 shown in FIG. 1 is a configuration shown to explain the molding process of the tubular compression molding apparatus according to an embodiment of the present invention, and the detailed structure of the heating medium circulation unit 300 is omitted.

The heat medium circulation unit 300 includes a heat medium oil tank 310 , a heating unit 320 , a first fluid pump 331 , a second fluid pump 332 , a first pressure valve 341 , and a second pressure valve 342 . ), and may further include a chiller 350 .

The heat medium circulation unit 300 supplies the heat medium oil 30 to the inner space of the housing 110 of the tubular mold 100 . At this time, the heat medium circulation unit 300 heats the heat medium oil 30 through a heating mechanism according to the curing temperature of the thermosetting resin impregnated in the carbon fiber prepreg 10 stacked in the cavity and supplies it to the tubular mold 100 . .

The thermal oil tank 310 supplies the thermal oil 30 used in the process, and may include one or more tanks. For example, when the thermal oil tank 310 is composed of two or more tanks, any one corresponding to the temperature of the thermal oil 30 supplied to the tubular mold 100 by varying the temperature of each of the two or more tanks. It can be configured to supply the thermal oil 30 in a specific tank. If the thermal oil tank 310 is composed of three tanks of low temperature, medium temperature, and high temperature, the thermal medium oil is supplied from the medium temperature tank during processing to the primary molding temperature, and the used thermal medium oil is also recovered to the medium temperature tank, and the primary molding temperature When processing starts at a secondary molding temperature higher than the temperature, the thermal medium oil is supplied and recovered from the high-temperature tank, and, if necessary, the thermal medium oil of the low-temperature tank can be used as a cooling water.

The heating unit 320 heats the thermal oil 30 of the thermal oil tank 310 to a set temperature and supplies it to the tubular mold 100 . A boiler structure may be used as an example of the heating unit 320 provided in the heating medium circulation unit 300 . The thermal medium circulation unit 300 includes one or more thermal oil tanks 310, and heats the thermal medium oil 30 inside the thermal oil tank 310 to a desired temperature through the supply pipe of the tubular mold 100. It is supplied to the inner space of the housing 110 .

At this time, the heating medium oil 30 heated by the heating unit 320 is supplied to the tubular mold 100 at a pressure set by the first fluid pump 331 located at the front end (inlet) of the tubular mold 100 . In addition, the thermal oil 30 used in the tubular mold 100 is discharged by the second fluid pump 332 located at the rear end (discharge port) of the tubular mold 100 and is again transferred to the thermal oil tank 310 . In this way, the thermal medium circulation unit 300 heats the thermal medium oil 30 discharged through the outlet of the tubular mold 100 again and supplies it to the inlet of the tubular mold 100, thereby circulating the thermal oil in the tubular compression molding apparatus. Manage and control.

In addition, the heat medium circulation unit 300 measures the temperature of the heat medium oil 30 inside the tubular mold 100 through a temperature sensor located inside the tubular mold 100 (inside the housing) to control the temperature of the heat medium oil 30 . By doing so, the temperature of the thermal medium oil 30 inside the tubular mold 100 can be constantly controlled.

The heat medium circulation unit 300 is a first fluid pump 331 to maintain the pressure of the heat medium 30 inside the tubular mold 100 when the heat medium oil 30 is supplied to the tubular mold 100 to maintain a preset pressure state. supplied through And the heat medium circulation unit 300 is provided with pressure valves 341 and 342 for regulating the pressure of the heat medium oil 30 inside the tubular mold unit. In particular, the second pressure valve 342 is located at the outlet end of the tubular mold 100, and blocks the valve when the pressure of the outlet is less than or equal to the set pressure according to the set pressure condition, and when the pressure of the outlet exceeds the set pressure By opening the valve, the heat medium oil 30 inside the tubular mold 100 is constantly maintained at a set pressure.

After forming the carbon fiber prepreg at high temperature and high pressure, before cooling it, the heat medium oil 30 is quickly discharged using the second fluid pump 332 to rapidly discharge the heat medium oil 30 inside the tubular mold 100 . make it For example, after the carbon fiber prepreg 10 is molded by supplying thermal oil at 250°C, and then cooling by supplying thermal oil at room temperature, thermal medium oil at 250°C remains, so that the thermal medium oil at room temperature is lower than the existing 250°C. The high temperature is maintained until all the heat medium oil is discharged. Therefore, the heat medium circulation unit 300 discharges all the heat medium oil of the previous temperature in the housing 110 of the tubular mold 100 using the second fluid pump 332 and then transfers the heat medium oil of a new temperature to the housing 110 . ) can be supplied to the inside to cool the tubular mold 100 more quickly.

As described above, when the heat medium circulation unit 300 delivers the heat medium oil 30 having a predetermined temperature to the tubular mold 100 , the lower mold 200 maintains the same temperature as the heat medium oil 3 . Since the upper surface of the carbon fiber prepreg 10 inserted between the tubular mold 100 and the lower mold 200 is in contact with the flexible film 120 and the lower surface is in contact with the lower mold 200, the upper surface and the lower If there is a temperature difference between the surfaces, distortion and defects occur during the curing process. Therefore, the heat medium circulation unit 300 controls the lower mold 200 to the same temperature as the tubular mold 100 (the same temperature as the heat medium oil) to prevent a problem due to a temperature difference.

In addition, after the carbon fiber prepreg 10 is completely cured and the tubular mold 100 is cooled, the thermal medium oil 30 inside the tubular mold 100 before separating the tubular mold 100 and the lower mold 200 ) must be completely discharged. In the present invention, since the lower direction of the tubular mold 100 is blocked by the flexible film 120, the tubular mold 100 and the lower mold 200 in a state in which the thermal medium oil 30 remains inside the tubular mold 100. If separated, the flexible membrane 120 is sagged in the direction of gravity by the weight of the thermal oil 30, which may cause excessive expansion or damage. Therefore, it is preferable that the heat medium circulation unit 300 completely discharges the heat medium oil 30 inside the tubular mold 100 before separating the tubular mold 100 and the lower mold 200 .

As such, when the heat medium oil 30 inside the tubular mold 100 is completely discharged, the flexible film 120 is in close contact with the horizontal partition 140 as shown before/after molding in FIG. 4 (a). Thus, it is possible to easily separate the mold and prevent damage to the flexible film 120 .

It is preferable to discharge the heat medium oil 30 inside the tubular mold 100 through the second fluid pump 332 located in the rear end (discharge port) direction of the tubular mold 100 . In addition, other than the method of using the second fluid pump 332 , a method of completely discharging the heating medium oil 30 present in the housing 110 of the tubular mold 100 using nitrogen gas may be used.

Such a thermal medium circulation unit 300 is provided with a motor for driving each part for circulating the thermal oil, and is designed by calculating the calorific value of the drive model for circulating the thermal oil.

5 is a view for explaining the isotropic pressure distribution structure of the tubular high-speed forming apparatus according to an embodiment of the present invention.

Referring to FIG. 5 , the direction of the arrow indicates the direction of the applied pressure, and the size of the arrow indicates the relative pressure difference. The conventional molding apparatus 510 located on the left side and the tubular compression molding apparatus 520 according to an embodiment of the present invention located on the right side have a clear difference in pressure distribution as shown in FIG. 5 .

In the conventional molding apparatus 510, both the upper and lower molds are formed of a material having rigidity, and a press is generally used to apply a necessary pressure. In the case of a flat or flat molded product, even if the pressure is transmitted using a general press, the pressure uniformity does not decrease significantly, but when it has a complex shape such as a curved or inclined surface, a difference in pressure transmitted to the flat surface and the curved/sloped surface occurs. As shown by the arrow shown in the conventional molding apparatus 510, the pressure transmission direction (vertical direction) and the surface angle of the molded product are perpendicular to the planar portion, so that strong pressure is transmitted, whereas on a curved or inclined surface, the pressure transmission direction (vertical direction) and the surface angle of the molded product are not perpendicular, so relatively little pressure is transmitted. Moreover, when the curvature/angle of the curved surface or the inclined surface is large, the difference from the pressure transmission direction (vertical direction) is excessive, and deformation may occur in the laminated form of the carbon fibers laminated therein by the vertical pressure. In addition, when press molding is used as in the conventional molding apparatus 510, the central portion receives a higher pressure than the outer portion. As described above, in the conventional molding apparatus 510, since the pressure applied to the carbon fiber prepreg varies depending on the shape and position, the pressure distribution is non-uniform and distortion occurs in the internal carbon fiber, which causes deterioration of the physical properties of the manufactured molded article. .

On the other hand, the tubular high-speed molding apparatus 520 according to an embodiment of the present invention expands the flexible membrane of the tubular mold through thermal oil to apply pressure to the carbon fiber prepreg, so that the pressure transmission direction at all positions is the molded product. It has an isotropic pressure distribution forming an angle perpendicular to the surface of .

6 is a flowchart of a tubular high-speed forming method according to an embodiment of the present invention.

Referring to FIG. 6 , in the tubular high-speed forming method according to an embodiment of the present invention, a first step (S601) of stacking a prepreg on a lower mold and engaging the tubular mold with the lower mold (S601), and injecting thermal oil into the upper part of the tubular mold a second step (S602) of forming a prepreg by expanding the flexible film (S603), a fourth step of discharging the thermal oil inside the tubular mold (S604), and a fifth step of cooling the lower mold (S605) ) is included.

In the first step (S601) of laminating the prepreg on the lower mold and engaging the tubular mold and the lower mold, the carbon fiber prepreg is laminated in the cavity on the lower mold, and the tubular mold is placed on the lower mold on which the carbon fiber prepreg is laminated. match and match At this time, when two or more cavities exist on the lower mold, carbon fiber prepregs may be laminated in all of the cavities, or carbon fiber prepregs may be laminated only in some cavities.

The tubular high-speed molding apparatus according to an embodiment of the present invention may further include a guide structure for precisely matching the meshing positions when the tubular mold and the lower mold are meshed. As an example, the guide structure is positioned in the form of a vertical guide bar at the four corners of the tubular mold and the lower mold, and moves the tubular mold in the vertical direction (up and down) through a separate power device or hydraulic device to separate the tubular mold and the lower mold. to join and separate.

The type of carbon fiber used in the carbon fiber prepreg to be laminated is not particularly limited, and as an example, a PAN-based or pitch-based carbon fiber may be used. In addition, carbon nanotubes other than general carbon fibers may be used, or a mixture of carbon fibers and carbon nanotubes may be used.

It is preferable to use an epoxy resin as the thermosetting resin impregnated in the carbon fiber prepreg. In addition, more specifically, the thermosetting resin impregnated in the carbon fiber is preferably used by mixing a solid epoxy resin and a liquid bisphenol A-type epoxy resin, and it is preferable to use a modified rubber by mixing it further. Epoxy resin is one of the thermosetting plastics. It has excellent mechanical strength, water resistance/electrical properties, and excellent dimensional stability, so it is advantageous for manufacturing high-quality and high-precision carbon fiber composite material molded products. However, these properties have a problem in that brittleness is destroyed when having a high level of cross-linking structure. Therefore, the brittle fracture problem can be solved by adding a modified rubber.

Next, in the second step ( S602 ) of injecting thermal oil into the upper part of the tubular mold, thermal fluid heated to a predetermined temperature is injected into the tubular mold by using the first fluid pump.

At this time, the second step (S602) of injecting the thermal medium into the tubular mold is preferably performed in two steps. When the thermal oil is injected into the tubular mold, it is first injected into the first region located above the horizontal partition. In addition, the thermal oil injected into the first region of the tubular mold is uniformly dispersed in the first region by the partition wall located on the upper surface of the horizontal partition. Then, the heat medium oil dispersed in the first area is moved to the second area under the horizontal partition through the micro-holes formed in the horizontal partition to contact the flexible film. As described above, in the present invention, when the thermal medium is injected into the tubular mold, the injected thermal oil directly expands the flexible film to prevent the carbon fiber prepreg from being molded from the portion close to the injection port and being non-uniformly formed. It is divided into a first region and a second region through a partition, and thermal oil is first injected into the first region and uniformly dispersed through the partition wall, and then the flexible film is uniformly expanded by moving it to the second region through the microholes of the horizontal partition. to make the carbon fiber prepreg uniformly molded in the entire area.

Next, in the third step (S603) of forming the prepreg by expanding the flexible film, the thermal oil moved to the second region expands the flexible film, and the flexible film is formed by applying heat and pressure to the carbon fiber prepreg located in the cavity of the lower mold. do. At this time, the heat medium oil injected into the tubular mold maintains a predetermined pressure preset by the first fluid pump and the pressure valve, and forms the carbon fiber prepreg at the preset pressure.

At this time, the third step ( S603 ) of forming the carbon fiber prepreg by expanding the flexible membrane with the heating medium oil is preferably performed in the following two steps.

First, the thermal medium is injected into the tubular mold at a predetermined pressure using the first fluid pump located in the front end (inlet) direction of the tubular mold so that the thermal oil has a stable pressure. And when a greater pressure is required, or when multi-stage pressure molding of more than primary molding of relatively low pressure and secondary molding of relatively high pressure is required, the molding step is located on the upper part of the tubular mold using the air pump of the air pressurization part The air membrane expands to increase the pressure inside the tubular mold. In addition, in the present invention, not only the pressure but also the temperature may perform molding at two or more different temperatures instead of one fixed temperature. As an example, firstly, thermal medium oil at a temperature of 100°C is supplied to a tubular mold at a pressure of 3bar using a fluid pump, and the carbon fiber prepreg is first molded for 3 minutes under the conditions of 100°C and 3bar, followed by a temperature of 250°C In a state in which thermal oil of As described above, in the present invention, by using both the primary pressurization process using the fluid pump and the secondary pressurization process using the air pressurization unit, the pressure can be freely controlled and high pressure can be achieved at low cost.

Next, in the fourth step (S604) of discharging the thermal medium oil inside the tubular mold, the carbon fiber prepreg is molded under predetermined temperature and pressure conditions, and then the thermal medium oil present inside the tubular mold is discharged. At this time, it is preferable to discharge the thermal oil inside the tubular mold by using a fluid pump located in the direction of the rear end (discharge port) of the tubular mold. Alternatively, a method of discharging the heat medium oil inside the tubular mold by injecting nitrogen gas that does not oxidize the heat medium oil even when it comes into contact with the high temperature heat medium oil may be used. If the tubular mold is separated from the lower mold while the thermal oil is not discharged, the thermal fluid inside the tubular mold excessively expands the flexible film, which may damage the flexible film or damage the molded article manufactured in this process. Therefore, it is required to discharge the thermal medium oil inside the tubular mold before separating the meshed mold.

Next, in the fifth step of cooling the lower mold ( S605 ), the carbon fiber prepreg is molded at a predetermined temperature and pressure to cool the manufactured article. This cooling process prevents deformation of the molded carbon fiber composite material and facilitates separation from the mold. And when the cooling process is finished, the carbon fiber composite material molded article manufactured by separating the tubular mold and the lower mold is separated from the mold.

In the tubular high-speed forming method according to an embodiment of the present invention described above, the description overlapping with the compression molding apparatus is omitted.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications may be made by those skilled in the art within the scope of the technical spirit of the present invention. possible.

10: carbon fiber prepreg 30: thermal oil
100: tubular mold 110: housing
120: flexible membrane 130: air pressurization unit
131: air membrane 132: air pump
140: horizontal partition 141: fine hole
142: bulkhead
200: lower mold
300: heat medium circulation unit 310: heat medium oil tank
320: heating unit 331: first fluid pump
332: second fluid pump 341, 342: pressure valve
510: conventional molding apparatus 520: tubular compression molding apparatus

Claims (10)

A space for accommodating thermal oil is provided therein, and it is composed of a housing having an open downward direction and a flexible membrane positioned in the open downward direction of the housing to block the open lower portion, an inlet through which thermal oil is injected is located at one position and the other side is located in the open downward direction of the housing. a tubular mold having an outlet at a corresponding position for discharging the thermal oil, and having a horizontal partition dividing the interior into a first region on the upper portion and a second region on the lower portion;
a lower mold having a cavity (cavity) corresponding to the shape of the molded article formed on the upper surface and engaged with the tubular mold; and
a heat medium circulation unit for supplying heat medium oil to the tubular mold at a preset temperature and pressure;
Including, tubular high-speed forming apparatus. According to claim 1,
In the tubular mold, thermal oil is first injected and dispersed in the first region located above the horizontal partition, and then the thermal fluid moves to the second region through micro-holes formed in the horizontal partition to expand the flexible film. . According to claim 1,
The tubular mold further comprises two or more partition walls formed on an upper surface of the horizontal partition. 4. The method of claim 3,
One end and the other end of the at least two partition walls are alternately opened to form a flow path so that the heat medium oil moves in a zigzag manner. 4. The method of claim 3,
The heat medium oil injected into the first area is dispersed through the flow path formed by the partition wall located on the upper surface of the horizontal partition, and then moves to the second area through the micro-holes of the horizontal partition to expand the flexible film. Device. 4. The method of claim 3,
The bulkhead is a tube-type high-speed forming apparatus having two or more tunnels through which the thermal oil passes. According to claim 1,
In the tubular high-speed forming apparatus, carbon fiber prepreg is laminated in the cavity of the lower mold in a state in which the tubular mold and the lower mold are separated, and after the tubular mold is meshed on the lower mold, it is heated through a heating unit By injecting thermal oil into the housing of the tubular mold and expanding the flexible film through the pressure of the thermal oil, while compressing the carbon fiber prepreg on the cavity, the thermal energy of the thermal oil is transferred to harden the carbon fiber prepreg, tubular high-speed molding Device. According to claim 1,
The heat medium circulation unit for discharging the heat medium oil inside the tubular mold by using a fluid pump, a tubular high-speed forming apparatus. According to claim 1,
The heat medium circulation unit measures the heat medium oil temperature inside the tubular mold through a temperature sensor located inside the tubular mold to adjust the heat medium oil temperature to a preset temperature. According to claim 1,
The flexible membrane expands by the thermal oil injected into the tubular mold and is in contact with the carbon fiber prepreg located inside the cavity of the lower mold at all positions of the internal shape of the cavity in a direction perpendicular to the internal shape of the cavity. A tubular high-speed forming device that transmits pressure.

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