JP4286355B2 - Composite material forming method and forming jig - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a composite material molding method and molding jig that can prevent gas residue of a molded product by vacuum suction in composite material molding, and more specifically, a composite material molding method and molding using a thermosetting polyimide resin. It relates to a jig.
[0002]
[Prior art]
A vacuum bag forming method is applied to a method for forming an aircraft composite material. In this vacuum bag forming method, a prepreg is laminated on a forming jig having a smooth surface, the laminated prepreg is covered with a breathable sheet and a vacuum bag film, and the internal space of the vacuum bag film is provided in the forming jig. This is a method of obtaining a molded product having a predetermined shape by vacuum suction from the mouth and pressurizing and curing in an autoclave.
[0003]
In the vacuum bag forming method, gas is mixed between the prepregs when the prepregs are laminated, or the gas generated during the molding remains in the prepreg and remains as bubbles after molding, such as the strength of the product. Quality will deteriorate significantly.
[0004]
As a method for effectively discharging the gas in the prepreg, in Japanese Utility Model Laid-Open No. 3-129422, a cylindrical body is arranged around the mold, and the gas can easily enter the cylindrical body during vacuum suction. A method for discharging gas in a prepreg is disclosed.
[0005]
Japanese Laid-Open Patent Publication No. 2-162016 discloses a method of discharging gas in a prepreg by gradually removing bubbles from the central part to the peripheral part of the composite material.
[0006]
Further, as related to these technical means, a mold using a porous air-permeable material (see Japanese Patent Application Laid-Open No. 60-24905) and a vacuum adsorption work holder (see Japanese Utility Model Publication No. 6-71039). It has been known.
[0007]
[Problems to be solved by the invention]
In the conventional molding method, the molding pressure at the time of molding the polyimide composite is 14 kgf / cm ² approximately at 320 ° C., (at 180 ℃ 7~8kgf / cm ²⁾ molding pressure of epoxy composites considerably higher than Since gas is generated during curing, vacuum suction is always required during molding. However, during vacuum suction, gas passages such as a breathable sheet are blocked by atmospheric pressure or molding pressure, and gas in the composite material is not discharged. There is a problem that the gas is sufficient and gas remains in the composite molded product as bubbles.
[0008]
Further, the technical means disclosed in the Japanese Utility Model Laid-Open No. 3-129422 can secure a gas passage even in such a case, but the suction is only the outer peripheral portion of the molded product. When the shape becomes large, there is a problem that the gas is not always sufficiently discharged from the center of the molded product.
[0009]
The present invention has been made in consideration of the above points, and even when the molded product is large, the gas in the composite material is surely discharged to prevent the gas from remaining in the molded product. An object of the present invention is to provide a molding method and a molding jig for a composite material that can easily obtain a high-quality composite material product.
[0010]
Another object of the present invention is to make it possible to obtain composite products of various shapes simply by exchanging the mold and to share the molding jig.
[0011]
[Means for Solving the Problems]
The molding method of the composite material of the present invention is formed by a groove portion provided in a mesh shape and closed grooves provided around these groove portions in communication with these groove portions , independently of each other. A breathable sheet is disposed on a molding jig having at least two vacuum suction paths provided on the surface thereof, a prepreg is laminated on the breathable sheet, and a sealing material is provided so as to surround the prepreg on the outer periphery of the molding jig. These are all covered with a vacuum bag film, the inside of the vacuum bag film is vacuum-sucked and subjected to pressure heat curing treatment to obtain a composite product, and vacuum suction is performed on the vacuum suction path on the surface of the forming jig. By doing this, it is possible to secure a suction path without being affected by atmospheric pressure or molding pressure, and it is possible to exhaust gas sufficiently from the entire bottom surface of the molded product. To get It can be.
[0012]
The molding method of the composite material of the present invention is formed by a groove portion provided in a mesh shape and closed grooves provided around these groove portions in communication with these groove portions , independently of each other. A mold having air permeability is arranged on a molding jig having at least two vacuum suction paths provided on the surface thereof, a prepreg is laminated on the molding mold, and the prepreg is surrounded on the outer periphery of the molding jig. A sealing material is arranged, the whole is covered with a vacuum bag film, the inside of the vacuum bag film is vacuum-sucked, and heat and pressure curing is performed to obtain a composite product. The molded product can be molded, and the molding jig can be shared.
[0013]
Forming jig of the present invention includes a groove intersecting provided on the surface, while communicating with these grooves are formed by a groove closed provided around these grooves, provided independently of each other Even if it has at least two vacuum suction paths, a support part formed between adjacent groove parts, and a base for connecting a vacuum device to the vacuum suction path, even if vacuuming is performed at one point of the groove parts The entire lower surface of the molded product can be sucked evenly.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0015]
1 and 2 show a forming jig used in the method for forming a composite material according to the first embodiment of the present invention. The forming jig 1 is formed of, for example, steel or aluminum alloy having a flat plate shape. A jig body 2 is provided. Two vacuum suction paths 3 are provided on the upper surface of the forming jig body 2 so as to form two independent paths.
[0016]
As shown in FIG. 2, each of the vacuum suction paths 3 is formed by recessed grooves 4 arranged in a grid shape, and a support portion 5 is formed between adjacent recessed grooves 4. A prepreg 9 described later is supported by these support portions 5. The recessed groove 4 has, for example, a width of 0.5 to 2.0 mm, a depth of about 2 mm, and a pitch of about 25 to 100 mm. A base 6 is connected to each vacuum suction path 3. The base 6 is connected to a vacuum device (not shown) via a suction hose 7.
[0017]
A method for forming a composite material according to the first embodiment of the present invention will be described.
[0018]
First, the forming jig 1 is fixedly arranged, and the base 6 of the forming jig 1 is connected to a vacuum device (not shown) via a suction hose 7 as shown in FIG.
[0019]
Next, the air permeable sheet 8 is disposed on the upper surface of the forming jig 1 so as to be positioned on the vacuum suction path 3 as shown in FIG. As shown in FIG. 5, the breathable sheet 8 is composed of an outer sheet 8a and an inner sheet 8b formed of a breathable glass cloth. The inner sheet 8b is formed of a glass cloth having a finer texture than that of the outer sheet 8a and is subjected to a mold release process.
[0020]
Next, a prepreg 9 in which carbon fiber or glass fiber is impregnated with a semi-cured resin is laminated on the breathable sheet 8, and the breathable sheet 10 is disposed on the laminated prepreg 9 as shown in FIG. . This breathable sheet 10 is composed of an outer sheet 10a and an inner sheet 10b formed of a breathable glass cloth. The inner sheet 10b is formed of a glass cloth having a finer texture than the outer sheet 10a, and is subjected to a mold release process.
[0021]
Next, as shown in FIGS. 3 and 4, for example, a silicone-based seal material 11 having a ring shape is disposed on the outer periphery of the forming jig 1 so as to surround both vacuum suction paths 3 and 3. A nylon or polyimide-based vacuum bag film 12 is disposed so as to seal the peripheral portion of the sealing material 11 provided on the upper surface of the forming jig 1. This completes the molding preparation stage.
[0022]
Next, the forming jig 1 is placed in the autoclave, a vacuum device (not shown) is operated, the internal space of the vacuum bag film 12 is vacuumed through each vacuum suction path 3, and the pressure is maintained while the state is maintained. A heat curing treatment is performed to obtain a composite product.
[0023]
According to the composite material molding method, the prepreg 9 placed on the molding jig 1 is vacuum-sucked from the entire lower surface, and the vacuum suction path 3 is not affected by atmospheric pressure or molding pressure. Therefore, the gas remaining between the prepregs 9 when the prepregs 9 are laminated and the gas generated from the prepregs 9 during molding can be discharged from the lower surface of the molding jig 1 to the outside during molding.
[0024]
Compared with the conventional molding method, the composite material molding method can perform vacuum suction in molding of the composite material without any trouble, and variously by processing the surface shape of the molding jig 1 to the shape of the molded product. Can be applied to various part shapes.
[0025]
In the first embodiment, the molding of a large-shaped product that extends over both vacuum suction paths 3 has been described. However, a small molded product that requires only one vacuum suction path 3 is molded. In this case, as shown in FIG. 6, it is possible to mold using only one vacuum suction path 3. As a result, the air-permeable sheets 8 and 10, the sealing material 11, the vacuum bag film 12, and the like can be reduced in size to the minimum necessary size.
[0026]
FIG. 7 shows a forming jig used in the method for forming a composite material according to the second embodiment of the present invention. The forming jig 21 has a forming jig body having the same configuration as the forming jig 1. 2 and a molding die 20 that is detachably disposed on the upper surface of the molding jig body 2. The molding die 20 has a molding mold 20a made of graphite having air permeability and a molded product.
[0027]
As shown in FIG. 7, the vacuum suction path 3 provided on the upper surface of the forming jig body 2 has recessed grooves 4 arranged in a grid shape, and a support portion 5 is formed between the adjacent recessed grooves 4. ing. The recessed groove 4 has a width of 0.5 to 2.0 mm, a depth of about 2 mm, and a pitch of about 25 to 100 mm. A base 6 is connected to each vacuum suction path 3. The base 6 is connected to a vacuum device (not shown) via a suction hose 7.
[0028]
A method for forming a composite material according to the second embodiment of the present invention will be described.
[0029]
First, as shown in FIG. 9, the molding die 20 is arranged on the upper surface of the molding jig 21, and the prepreg 9 is laminated on the upper surface of the molding mold 20 a of the molding die 20 via the porous release film 22.
[0030]
Next, as shown in FIGS. 8 and 9, a ring-shaped sealing material 11 is disposed on the outer periphery of the forming jig 21 so as to surround both vacuum suction paths 3, and the vacuum bag film 12 is placed thereon. Deploy.
[0031]
Next, a vacuum device (not shown) is operated to suck the internal space of the vacuum bag film 12 through each vacuum suction path 3 and maintain the state, and the prepreg laminate is subjected to pressure heat curing treatment to obtain a composite material product. Get.
[0032]
In the molding method of the composite material, since the molding is performed using the molding die 20, the molded product can be sufficiently vacuum sucked even if the mesh of the vacuum suction path 3 provided in the molding jig 21 is rough. Molded products of various shapes can be formed simply by exchanging the mold 20. Further, by sharing the forming jig, the manufacturing cost of the forming jig can be kept low.
[0033]
In the second embodiment, the case where the mold 20 is made of graphite having air permeability has been described. However, as shown in FIG. 10, air permeability is ensured for a mandrel 31 made of steel or aluminum alloy. Therefore, it is also possible to use a molding die 30 having a vacuum suction hole 32 having a diameter of 1.0 to 2.0 mm and a pitch of about 1 inch.
[0034]
In both embodiments, the case where the vacuum suction path 3 is provided independently at two positions on the upper surface of the forming jig 2 has been described. However, a single vacuum suction path 3 is provided over the entire upper surface of the forming jig 2. Alternatively, the vacuum suction paths 3 may be provided at three or more locations on the upper surface of the forming jig 2. The configuration of the vacuum suction path 3 is not limited to the recessed groove 4 arranged in a grid shape, and may be a spiral groove.
[0035]
【The invention's effect】
As described above, according to the present invention, the suction path is affected by the atmospheric pressure and the molding pressure by laminating the prepreg via the air-permeable sheet on the molding jig having the vacuum suction path on the surface. The gas can be reliably discharged to the outside from the entire lower surface of the molded product, and a high-quality composite material product without bubbles can be molded.
[0036]
In addition, the present invention is arranged such that a breathable mold is placed on a molding jig having a vacuum suction path on the surface, and a prepreg is laminated on the mold, so that the suction path affects the atmospheric pressure and the molding pressure. It can be ensured without being done, and it is possible to form molded products of various shapes simply by exchanging the forming die, and to share the forming jig.
[0037]
Furthermore, in the present invention, the vacuum suction path is formed by the intersecting groove portions, and the support portion is formed between the adjacent groove portions. It is possible to suck evenly.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a state in which a prepreg is arranged on a forming jig used in a method for forming a composite material according to a first embodiment of the present invention.
FIG. 2 is a view showing a configuration of a vacuum suction path of the forming jig of FIG.
FIG. 3 is a view showing a state in which the forming jig of FIG. 1 is covered with a vacuum bag film.
4 is a cross-sectional view of the main part of FIG. 3;
FIG. 5 is a diagram showing a configuration of a breathable sheet.
6 is a view corresponding to FIG. 3, showing a state in which a molded product is molded using one vacuum suction path.
FIG. 7 is a perspective view showing a state in which a prepreg is arranged on a forming jig used in a method for forming a composite material according to a second embodiment of the present invention.
8 is a view showing a state in which the forming jig of FIG. 7 is covered with a vacuum bag film.
9 is a cross-sectional view of the main part of FIG.
FIG. 10 is a perspective view showing a mold having a different structure according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Forming jig 2 Forming jig main body 3 Vacuum suction path 4 Recess groove 5 Support part 6 Base 7 Suction hose 8, 10 Breathable sheet 8a, 10a Outer sheet 8b, 10b Inner sheet 9 Prepreg 11 Sealing material 12 Vacuum bag film 20 Mold 20a Mold 21 Mold jig 22 Release film

Claims (8)

At least two vacuum suction paths provided independently of each other are formed by grooves provided in a mesh shape and closed grooves provided around these grooves while communicating with the grooves. Place a breathable sheet on the forming jig on its surface,
Laminating a prepreg on a breathable sheet,
Place a sealing material around the prepreg around the outer periphery of the forming jig,
Cover these whole with vacuum bag film,
A method of forming a composite material, wherein the inside of a vacuum bag film is vacuum-sucked and subjected to pressure heat curing.   The method for molding a composite material according to claim 1, wherein a breathable sheet is interposed between the prepreg and the vacuum bag film. At least two vacuum suction paths provided independently of each other are formed by grooves provided in a mesh shape and closed grooves provided around these grooves while communicating with the grooves. Place a breathable mold on the molding jig on the surface,
Laminating a prepreg on a mold,
Place a sealing material around the prepreg around the outer periphery of the forming jig,
Cover these whole with vacuum bag film,
Vacuum the inside of the vacuum bag film,
A method for forming a composite material, characterized by subjecting to pressure heat curing.   The method for molding a composite material according to claim 3, wherein a release film having air permeability is interposed between the mold and the prepreg. The said vacuum suction path has a nozzle | cap | die for connecting a vacuum apparatus to the said vacuum suction path which is connected to the said groove part or the said closed groove | channel, The Claim 1 thru | or 4 characterized by the above-mentioned. Composite material molding method. At least two vacuum suction paths provided independently of each other, formed by intersecting grooves provided on the surface and closed grooves provided around these grooves while communicating with these grooves;
A support formed between adjacent grooves,
A molding jig having a base for connecting a vacuum device to a vacuum suction path.   The forming jig according to claim 6, wherein the support portion has a grid shape.   The molding jig according to claim 6 or 7, wherein a molding die having air permeability is disposed on the vacuum suction path.

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