KR20220112980A - Tube type compression molding device - Google Patents

Abstract

A tubular compression molding apparatus according to the present invention comprises: a tubular mold which includes a housing that has a space storing thermal oil therein and is open in a downward direction and a flexible membrane that is located in the open downward direction of the housing and blocks an open lower part, and in which an inlet through which the thermal oil is injected is located on one side and an outlet through which the thermal oil is discharged is located at a corresponding position on the other side; a lower mold in which a cavity corresponding to a shape of a molded product is formed on an upper surface, and which meshes with the tubular mold; and a thermal oil circulation unit which includes a heating mechanism adjusting the temperature of the thermal oil, a supply pipe transferring the heated thermal oil to the inlet of the tubular mold at a predetermined pressure, a discharge pipe transferring the thermal oil discharged from the tubular mold to the heating mechanism, and a pressure control valve controlling the pressure of the thermal oil inside the tubular mold, wherein the tubular compression molding apparatus has a structure in which the flexible film is expanded by the pressure of the thermal oil injected into the tubular mold to apply heat and pressure to a carbon fiber impregnated with a thermosetting resin located in the cavity of the lower mold for molding. The tubular compression molding apparatus enables high-speed molding while achieving high precision and high quality.

Description

Tubular compression molding device {TUBE TYPE COMPRESSION MOLDING DEVICE}

The present invention relates to a compression molding apparatus using a carbon fiber composite material, and more particularly, to a tubular compression molding apparatus using a carbon fiber composite material.

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 chemical resistance. 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 preform or a target product in the form of a carbon fiber composite material impregnated with a thermosetting resin and molded rather than 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-shaped 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 physical 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 material molded product. It is difficult to maintain, and does not solve the problem of uneven pressure.

Autoclave molding is a process for solving 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 can manufacture high-precision and high-quality molded products by applying pressure in the vertical direction to the surface regardless of the shape of the molded product by using vacuum. 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 above 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 portion, and an inlet through which thermal oil is injected at one position A tubular mold in which the discharge port through which the thermal oil is discharged is located at the position corresponding to the other side, a cavity corresponding to the shape of the molded product is formed on the upper surface, and the lower mold engaged with the tubular mold and heating to control the temperature of the thermal oil A device, a supply pipe that delivers the heated thermal oil to the inlet of the tubular mold part at a predetermined pressure, a discharge pipe that delivers the thermal fluid discharged from the tubular mold part to the heating mechanism, and a pressure control valve for regulating the pressure of the thermal fluid inside the tubular mold part The flexible film expands by the pressure of the thermal oil injected into the tubular mold in a state in which the tubular mold and the lower mold are engaged, and heat and pressure are applied to the carbon fiber impregnated with the thermosetting resin located in the cavity of the lower mold. It is achieved by a tubular compression molding apparatus for molding by adding.

Preferably, in the tubular compression molding apparatus, carbon fibers impregnated with a thermosetting resin are 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 engaged on the lower mold, through a heating mechanism By injecting heated thermal oil into the housing of the tubular mold and expanding the flexible film through the pressure of the thermal oil, the carbon fiber impregnated with the thermosetting resin inside the cavity is compressed while the thermal energy of the thermal oil is transferred to the carbon fiber impregnated with the thermosetting resin. The thermosetting resin may be to harden the impregnated carbon fiber.

Preferably, the heat medium circulation unit supplies the heat medium oil heated to the first molding temperature to the tubular mold for a predetermined time after the tubular mold is meshed on the lower mold to perform the primary molding, and is higher than the first molding temperature. Secondary molding is carried out by supplying thermal oil heated to a high second molding temperature to the tubular mold, and after the carbon fiber impregnated with the thermosetting resin located inside the cavity is cured, the thermal oil is cooled and supplied to the tubular mold. have.

Preferably, after the tubular mold is cooled, the heat medium circulation unit may inject nitrogen gas to discharge the heat medium oil inside the tubular mold.

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 to apply the same amount of pressure in the direction perpendicular to the internal shape of the cavity at all positions of the internal shape of the cavity while in contact with the carbon fiber located inside the cavity of the lower mold. may be conveying.

Preferably, the heating medium circulation unit supplies the thermal medium oil having the same temperature as that of the thermal medium oil supplied to the tubular mold to a flow path formed inside the lower mold to adjust the temperature of the lower mold to be the same as that of the tubular mold.

The tubular compression molding apparatus according to an embodiment of the present invention uses a tubular structure and transfers uniform pressure using a process method of applying heat and pressure to a carbon fiber composite material using thermal oil, thereby having a short molding cycle and high speed While enabling molding, it is possible to manufacture high-precision and high-quality molded articles with very few voids at a relatively low cost.

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 tubular compression molding apparatus according to an embodiment of the present invention.
2 is a side view of a tubular compression molding apparatus according to an embodiment of the present invention.
3 is a conceptual diagram of the operation of the tubular compression molding apparatus according to an embodiment of the present invention.
4 is a view for explaining the isotropic pressure distribution structure of the tubular compression molding apparatus 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 tubular compression molding apparatus according to an embodiment of the present invention, and FIG. 2 is a side view of the tubular compression molding apparatus according to an embodiment of the present invention.

3 is a conceptual diagram of the operation of the tubular compression molding apparatus according to an embodiment of the present invention.

1 to 3, the tubular compression molding apparatus according to an embodiment of the present invention uses a tubular mold 100 and a lower mold 200 to mold the carbon fiber 10 impregnated with a thermosetting resin.

The tubular mold 100 is composed of a housing 110 and a flexible membrane 120 .

The housing 110 has a space for accommodating the thermal oil 30 therein, and has an open downward 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 portion.

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 effectively transfer heat and pressure to the carbon fiber 10 impregnated with the thermosetting resin 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 positioned in the direction corresponding to each other so that the

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 in order to prevent physical damage and thermal deformation caused by the thermal oil 30 , and the pressure from the thermal oil 30 is applied to the carbon fiber 10 impregnated with the thermosetting resin. It is desirable to have a high elongation in order to transmit effectively. As an example, the flexible membrane 120 preferably has a shore hardness of 30 to 40, a tensile strength of 1400 to 1800 psi, a tear strength of 200 ppi or more, and an elongation of 900%.

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 impregnated with the thermosetting resin is positioned inside the cavity and is molded by the heat and pressure transmitted by the tubular mold 100 .

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

In addition, the lower mold 200 may have a flow path through which the heat medium oil can pass therein. The flow path inside the lower mold 200 has a structure through which the heat medium oil supplied from the heat medium circulation unit 300 passes, and the lower mold 200 may be heated or cooled by the heat medium oil passing through the flow path. However, the heating and cooling structure of the lower mold 200 is not limited to the structure by the heat medium oil passing through the flow path, and other structures such as a heater generally used for heating or cooling the mold may be used.

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. In this way, 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) transmits pressure to the carbon fiber impregnated with a thermosetting resin 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 impregnated with the thermosetting resin located on the cavity of the lower mold 200 according to the thermal conductivity of the flexible film 120. . 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 mold the carbon fiber impregnated with the thermosetting resin.

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. In the case of mineral oil, the operating temperature is 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.

3 is a conceptual diagram of the operation of the tubular compression molding apparatus according to an embodiment of the present invention, and shows the heating medium circulation unit 300 . The heating medium circulation unit 300 shown in FIG. 3 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 heating medium circulation unit 300 includes a heating mechanism for controlling the temperature of the thermal oil, a supply pipe for transferring the heated thermal oil to the inlet of the tubular mold part at a predetermined pressure, a discharge pipe for delivering the heating medium oil discharged from the tubular mold part to the heating mechanism, and It includes a pressure regulating valve for regulating the pressure of the heat medium oil inside the tubular mold part.

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 carbon fiber impregnated with the thermosetting resin laminated in the cavity, and supplies it to the tubular mold 100 .

A boiler structure may be used as an example of the heating mechanism of the heat medium circulation unit 300 . The heating medium circulation unit 300 has one or more boiler tanks, heats the thermal medium oil 30 in the boiler tank to a desired temperature, and supplies it to the inner space of the housing 110 of the tubular mold 100 through a supply pipe. do. At this time, the heating medium circulation unit 300 may control and deliver the temperature of the heating medium oil 30 according to the required temperature using one boiler tank. In addition, the heating medium circulation unit 300 uses two or more boiler tanks, and after heating the thermal medium oil 30 to different temperatures in each of the two or more boiler tanks, sequentially different temperatures in different boiler tanks according to the molding process. of the thermal oil 30 may be supplied to the inner space of the housing 110 of the tubular mold 100 . And the heat medium circulation unit 300 heats the temperature of the heat medium oil 30 to a temperature required for curing the carbon fiber impregnated with the thermosetting resin, as well as a temperature for cooling the cured molded product. It can be supplied by lowering the temperature of

For example, the heat medium circulation unit 300 heats the heat medium oil 30 to a first temperature in the first boiler tank and supplies it to the tubular mold 100, and after curing for a predetermined time, the second boiler tank in the next process step Heating the thermal oil 30 to a second temperature higher than the first temperature in the tubular mold 100 and supplying it to the tubular mold 100 to proceed with curing, and after curing is completed, the heating medium oil at room temperature or lower than room temperature in the third boiler tank ( 30) may have a structure of three boiler tanks for transferring the heating medium oil 30 serving as cooling water to the tubular mold 100 that has been cured by controlling the temperature.

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 supplies the heat medium oil 30 so that the pressure of the heat medium 30 inside the tubular mold 100 maintains a preset pressure when the heat medium oil 30 is supplied to the tubular mold 100 . To this end, the heat medium circulation unit 300 is provided with a pressure control valve for controlling the heat medium oil 30 inside the tubular mold unit. The pressure control valve is located at the outlet end of the tubular mold 100, and blocks the valve when the pressure at the outlet is below the set pressure according to the set pressure condition, and opens the valve when the pressure at the outlet exceeds the set pressure to open the tubular mold. (100) The internal heat medium oil 30 is constantly maintained at a set pressure.

The heat medium circulation unit 300 uses nitrogen gas after the intermediate process of delivering the heat medium oil 30 of different temperatures or the manufacturing process of the molded product is completed, and the heat medium oil present inside the housing 110 of the tubular mold 100 . (30) can be completely discharged. When the heat medium oil 30 of different temperature is supplied, if there is a heat medium oil 30 of a different temperature that was previously used, even if the heat medium oil 30 of a new temperature is supplied, the temperature inside the tubular mold 100 is completely It takes a certain amount of time to change. In particular, when the temperature difference between the thermal medium oils 30 of different temperatures is large, the time required for the temperature change becomes large. For example, after curing the carbon fiber 10 impregnated with a thermosetting resin by supplying thermal oil at 250 ° C., when cooling by supplying thermal oil at room temperature, the thermal medium oil at 250 ° C remains, so that the thermal medium oil at room temperature is the existing thermal medium. The high temperature is maintained until all of the 250℃ thermal oil is discharged. Therefore, the heating medium circulation unit 300 discharges all the heating medium oil of the previous temperature in the housing 110 of the tubular mold 100 using nitrogen gas, and then supplies the heating medium oil of a new temperature into the housing 110. The tubular mold 100 can be cooled more quickly.

As described above, when the thermal medium circulation unit 300 delivers the thermal medium oil 30 having a predetermined temperature to the tubular mold 100 , the thermal medium circulation unit 300 supplies the thermal medium oil of the same temperature to the lower mold 200 . By passing through the inner flow path, the temperature of the lower mold 200 is adjusted to be the same as that of the tubular mold 100 . The carbon fiber impregnated with a thermosetting resin inserted between the tubular mold 100 and the lower mold 200 has an upper surface in contact with the flexible film 120 and a lower mold 200 on the lower surface, so the upper surface and the lower surface If there is a temperature difference between the surfaces, distortion and defects occur during the curing process. Accordingly, the thermal medium circulation unit 300 transmits the thermal medium oil of the same temperature as that of the tubular mold 100 to the lower mold 200 to prevent a problem due to a temperature difference.

In addition, after the carbon fiber 10 impregnated with the thermosetting resin is completely cured and the tubular mold 100 is cooled, before separating the tubular mold 100 and the lower mold 200 , the heating medium inside the tubular mold 100 . It is necessary to completely drain the oil 30 . 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 discharge the heat medium oil 30 inside the tubular mold 100 using nitrogen gas before separating the tubular mold 100 and the lower mold 200 .

In the present invention, the heat medium circulation unit 300 preferably uses nitrogen gas when discharging the heat medium oil 30 inside the tubular mold 100 . In the case of using general air, there is an advantage of reducing the process cost, but oxygen in the air reacts with the heating medium oil 30. In particular, the high temperature thermal medium oil 30 has high reactivity with oxygen, so that the thermal medium oil 30 is oxidized. makes reuse difficult. On the other hand, nitrogen gas has a low reactivity with the thermal medium oil 30 , so that the thermal medium oil 30 inside the tubular mold 100 is not denatured, thereby enabling the reuse of the thermal medium oil 30 .

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.

The molding process of the carbon fiber composite material molded article using the tubular compression molding apparatus according to an embodiment of the present invention is as follows.

First, in a state in which the tubular mold 100 and the lower mold 200 are separated, carbon fibers impregnated with a thermosetting resin are laminated on the cavity of the lower mold 200 .

In this case, the type of carbon fiber used 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 into the carbon fiber. In addition, more specifically, it is preferable to use a mixture of a solid epoxy resin and a liquid bisphenol A type epoxy resin as the thermosetting resin impregnated in the carbon fiber, and it is preferable to further mix and use a modified rubber. Epoxy resin, one of thermosetting plastics, 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.

When the carbon fiber impregnated with a thermosetting resin is laminated on the cavity of the lower mold 200 , the tubular mold 100 and the lower mold 200 are meshed with each other. At this time, the tubular compression 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 100 and the lower mold 200 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 100 and the lower mold 200, and the tubular mold 100 is vertically moved (up and down) through a separate power device or hydraulic device. moves to engage and separate the tubular mold 100 and the lower mold 200 .

When the tubular mold 100 and the lower mold 200 are engaged, the thermal medium circulation unit 300 heats the thermal oil 30 through the heating mechanism and heats the thermal oil 30 through the supply pipe to the inlet of the tubular mold 100. The heat medium oil 30 is filled in the housing 110 of the tubular mold 100 by supplying it. And the thermal medium oil 30 inside the housing 110 expands the flexible film 120 , so that the carbon fiber 10 impregnated with the thermosetting resin laminated in the cavity of the lower mold 200 is in close contact with the lower mold 200 . As much as possible, pressure is applied and heat is transferred together through the thermal energy of the thermal oil 30 . As described above, the carbon fiber 10 impregnated with the thermosetting resin laminated by the flexible film 120 expanded by the pressure of the thermal oil 30 is pressed and molded at high temperature and high pressure. At this time, depending on the molded article to be manufactured, the thermal medium oil 30 may be delivered at a fixed temperature and pressure to perform molding, and the thermal medium oil 30 may be delivered at two or more different temperatures and pressures to perform molding. .

As an example, the heat medium circulation unit 300 supplies the heat medium oil heated to the first molding temperature to the tubular mold 100 for a predetermined time after the tubular mold 100 is meshed with the lower mold 200 to 1 After the secondary molding is performed, the thermal medium oil heated to a second molding temperature higher than the first molding temperature may be supplied to the tubular mold 100 to perform secondary molding. In addition, at this time, the pressure of the heating medium may be transmitted by changing the setting of the pressure control valve to transmit two or more different pressures. Through this process, the tubular compression molding apparatus of the present invention can manufacture a carbon fiber composite material molded article by precisely controlling the temperature and pressure of the thermal medium oil 30 .

As described above, after the carbon fiber 10 impregnated with the thermosetting resin is cured by expanding the flexible film 120 through the thermal oil 30 to form a carbon fiber composite molded article, the heating medium circulation unit 300 Cools the thermal medium oil 30 and supplies it to the tubular mold 100 to cool the tubular mold 100 and the cured carbon fiber composite material molded product together. This cooling process prevents deformation of the molded carbon fiber composite material and facilitates separation from the mold.

When the cooling process is completed, the heating medium circulation unit 300 delivers nitrogen gas into the housing 110 of the tubular mold 100 , and the heating medium oil 30 positioned inside the housing 110 of the tubular mold 100 . After emptying the inside of the tubular mold 100 by discharging all of them to the outside through the outlet, the carbon fiber composite molded article manufactured by separating the tubular mold 100 and the lower mold 200 is separated from the mold.

4 is a view for explaining the isotropic pressure distribution structure of the tubular compression molding apparatus according to an embodiment of the present invention.

Referring to FIG. 4 , the direction of the illustrated arrow indicates the direction of the applied pressure, and the size of the arrow indicates the relative pressure difference. The conventional molding apparatus 410 located on the left and the tubular compression molding apparatus 420 according to an embodiment of the present invention located on the right have a clear difference in pressure distribution as shown in FIG. 4 .

In the conventional molding apparatus 410, 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, the pressure uniformity does not decrease significantly even when pressure is transmitted using a general press, but when it has a complex shape such as a curved surface or an 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 410, 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 410, the central portion receives a higher pressure than the outer portion. As described above, in the conventional molding apparatus 410, since the pressure applied to the carbon fiber impregnated with the thermosetting resin varies depending on the shape and position, the pressure distribution is non-uniform and distortion occurs in the internal carbon fiber, which decreases the physical properties of the manufactured molded article. causes

On the other hand, in the tubular compression molding apparatus 420 according to an embodiment of the present invention, the flexible film of the tubular mold is expanded through thermal oil to apply pressure to the carbon fiber impregnated with the thermosetting resin, pressure is transmitted at all positions. It has an isotropic pressure distribution whose direction forms an angle perpendicular to the surface of the molded product and transmits the same amount of pressure in the vertical direction at all positions. can do.

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. It is possible.

100: tubular mold
110: housing
120: flexible membrane
200: lower mold
300: heat medium circulation unit
410: conventional molding apparatus
420: tubular compression molding device

Claims (7)

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 part, and an inlet through which thermal oil is injected is located at one position and the other side a tubular mold having an outlet at which the thermal oil is discharged at a corresponding position;
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 heating mechanism for controlling the temperature of the thermal oil, a supply pipe for transferring the heated thermal oil to the inlet of the tubular mold part at a predetermined pressure, a discharge pipe for delivering the thermal oil discharged from the tubular mold part to the heating mechanism, and the tubular mold part a heat medium circulation unit having a pressure regulating valve for regulating the internal heat medium oil pressure;
includes,
In a state in which the tubular mold and the lower mold are engaged, the flexible film expands by the pressure of the thermal oil injected into the tubular mold, and heat and pressure are applied to the carbon fiber impregnated with the thermosetting resin located in the cavity of the lower mold to form , tubular compression molding equipment. According to claim 1,
The tubular compression molding device,
In a state in which the tubular mold and the lower mold are separated, a carbon fiber impregnated with a thermosetting resin is laminated in the cavity of the lower mold, and after the tubular mold is meshed on the lower mold, the heating medium heated through the heating mechanism By injecting oil into the housing of the tubular mold to expand the flexible film through the pressure of the thermal oil, while compressing the carbon fiber impregnated with the thermosetting resin inside the cavity, the thermal energy of the thermal oil is transferred to the carbon fiber impregnated with the thermosetting resin A tubular compression molding device that hardens the carbon fiber impregnated with a thermosetting resin. 3. The method of claim 2,
After the tubular mold is meshed with the lower mold, the heating medium circulation unit supplies the heating medium oil heated to the first molding temperature to the tubular mold for a predetermined time to perform primary molding, and then at the first molding temperature. Secondary molding is performed by supplying thermal oil heated to a second higher molding temperature to the tubular mold, and after the carbon fiber impregnated with a thermosetting resin located inside the cavity is cured, the thermal medium is cooled to cool the tubular mold A tubular compression molding device supplied by 4. The method of claim 3,
After the tubular mold is cooled, the heat medium circulation unit injects nitrogen gas to discharge the heat medium oil inside the tubular mold. 3. The method of claim 2,
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. 3. The method of claim 2,
The flexible membrane expands by the thermal oil injected into the tubular mold and in contact with the carbon fiber located inside the cavity of the lower mold, at all positions of the inner shape of the cavity, the same amount of pressure in the direction perpendicular to the inner shape of the cavity Delivery, tubular compression molding device. According to claim 1,
The heat medium circulation unit supplies heat medium oil at the same temperature as the heat medium oil supplied to the tubular mold to the flow path formed inside the lower mold, and adjusts the temperature of the lower mold to be the same as that of the tubular mold.

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