JP4801292B2 - Method for forming composite hollow parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a composite material hollow part, and more particularly to a technique suitable for use in forming a deformed cross-section composite material hollow part in which the cross-sectional shape of a hollow portion changes.
[0002]
[Prior art]
Conventionally, when a hollow part is formed with a composite material such as a carbon fiber prepreg (hereinafter referred to as CFRP), a forming method is employed in which vacuum / heat forming is performed using a silicon bag. As in the example shown in FIG. 18, the composite hollow part 04 in this case is simple so that the cross-sectional area of the hollow portion 04a is relatively large and the cross-sectional shape thereof changes constant or gently.
In such a composite material hollow part 04, as shown in FIG. 17, the composite material hollow part 04 is formed between the lower mold 02 and the upper mold 03. In this molding method, the shape of the hollow portion 04a of the composite material hollow part 04 is molded using the silicon bag 07 as a core.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional molding method, when forming a deformed cross-section composite material hollow part in which the cross-sectional shape of the hollow portion is not constant, the silicon bag 07 may not be taken out after the molding is completed. In particular, when the deformed cross-section composite hollow part is elongated as a whole and the shape of the hollow part is complicated or narrowly changed in the longitudinal direction, the silicon bag 07 used for forming the hollow part can be taken out after the molding is completed. It becomes impossible. In such a case, it may be difficult to ensure the thickness necessary for the presence of the silicon bag 07.
Furthermore, since a special jig is required for manufacturing the above-described silicon bag 07, there is a problem in that it is disadvantageous in terms of cost.
[0004]
The present invention has been made in view of the above circumstances, and the object of the present invention is not only to form a composite hollow part having a simple cross-sectional shape, but also to easily form a hollow composite part having a modified cross section and remove the core. Another object of the present invention is to provide a method for forming a composite hollow part that can be carried out and that can also reduce costs.
[0005]
[Means for Solving the Problems]
The present invention has solved the above problems by employing the following means.
The method for molding a composite hollow part according to claim 1 is a molding method for vacuum / pressurizing / heating molding a composite hollow part having a hollow part, and a core material for molding the shape of the hollow part After using the soluble member to place the core in a tubing film and setting it in a predetermined position in the mold, and after completing the molding / curing of the composite hollow part by performing vacuum / pressure / heating molding Then, a solvent is poured into the tubing film to dissolve the core, and the jelly-shaped core is pulled out from the hollow portion together with the tubing film, and between the inner surface of the hollow portion and the tubing film, A release / breathing member in which a release film and a ventilation cloth are integrated is interposed, and a release paper is provided between the vertical wall portion and the corner R portion of the hollow portion and the release / breathing member. It is characterized in that the interposed.
[0006]
According to such a method for molding a composite hollow part, after the molding / curing is completed, a core made of a soluble member and dissolved in a jelly shape by pouring a solvent into the tubing film, the cross-sectional shape is Even in a narrow hollow portion that changes in a complicated manner, the core can be easily removed from the hollow portion together with the tubing film.
Further, when removing the tubing film and the jelly-like core, the function of easily separating the tubing film from the inner surface of the hollow portion can be ensured by the presence of the release / venting member. For example, a release paper such as Tedla Film (registered trademark) functions as an edge cut between the mold release / venting member and the hollow portion, so that it is possible to prevent the two members from being unnecessarily bonded during heat molding. it can.
[0007]
The method for molding a composite hollow part according to claim 2 is characterized in that the soluble member is foamed urethane and the solvent is methyl ethyl ketone.
[0008]
According to such a method for molding a composite hollow part, the foamed urethane soaked in methyl ethyl ketone dissolves into a jelly shape, so that the core can be easily removed.
[0009]
The method for forming a composite hollow part according to claim 3 is characterized in that the tubing film is a tubular nylon bag.
[0010]
According to such a method for forming a composite hollow part, the cost can be reduced by using a commercially available inexpensive tubing film.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method for forming a composite hollow part according to the present invention will be described with reference to the drawings.
2, reference numeral 1 is a molding die, 2 is a lower die, 3 is an upper die, 4 is a composite hollow part, 5 is a release / venting member (release paper), 6 is a tubing film, and 7 is a medium. A child. As shown in FIGS. 1A and 1B, the composite hollow part 4 to be molded here is elongated as a whole, and the shape of the hollow part 4a is changed in a complicated manner in the longitudinal direction. Further, in the illustrated cross-sectional shape, there are narrow portions 4b and bent portions 4c.
[0018]
The composite material used as the material of the composite hollow part 4 is a material having characteristics superior to those of the original material alone by combining fibers (reinforcing material) and resin (matrix, binder). Such composite materials include carbon fiber prepreg (CFRP), glass fiber prepreg (GFRP), aramid fiber prepreg (KFRP), etc., depending on the heat resistance temperature at which the resin is used. It is connected.
(1) Polyester (93 ° C)
(2) Epoxy (150-177 ° C)
(3) Phenol (180 ° C)
(4) Bismaleimide (250 ° C)
(5) Polyimide (300 ° C)
(6) Carbon / carbon (1700 ° C)
The CFRP described above is used by laminating skin-like materials, but the CFRP includes a cloth material and a unidirectional material, which are appropriately combined by taking advantage of the characteristics of both materials.
[0019]
For forming the composite hollow part 4 as described above, a forming method by vacuum / pressurization / heating is employed. In the present invention, the hollow part 4a is formed of a soluble member such as urethane foam. 7 to mold. Soluble members such as urethane foam are materials that melt easily when immersed in a solvent. Methyl ethyl ketone is known as a solvent for melting foamed urethane.
It should be noted that the selection conditions for the soluble member include, in addition to being shrunk by heating and being able to dissolve in the solvent, formability as the core 7 produced in accordance with the shape of the hollow portion 4a is also included. is there.
[0020]
The core 7 is set in a predetermined position in the mold by being placed in a tubing film 6 made of a tubular nylon bag when vacuum / pressurizing / heating. Tubular nylon bags are generally commercially available and can be obtained easily and inexpensively.
[0021]
The above-described core 7 and tubing film 6 are unnecessary for the composite hollow part 4 after completion of molding. Therefore, it is desirable that the core 7 and the tubing film 6 be easily removed without remaining as foreign matter in the product. Therefore, in order to facilitate the separation of the tubing film 6 and the hollow portion 4a, the release / ventilating member 5 is interposed when the core 7 is set. As this mold release / venting member 5, what is called a vapor soap is preferable. This release / venting member (hereinafter referred to as vapor soap) 5 is a secondary material formed by integrating the release film and the ventilation cloth, and the core 7 and the tubing film 6 are arranged over the entire circumference of the hollow portion 4a. Arranged to wrap. The vapor soap 5 is also removed after the molding is completed.
[0022]
Hereinafter, a method for forming a composite hollow part using the above-described core 7, tubing film 6, vapor soap 5 and the like will be briefly described in the order of specific main forming steps. 3 to 15 below are schematic cross-sectional views of the composite hollow part 4 and its molding die 1 with emphasis on explaining the process. Shown exaggerated than the actual.
[0023]
First, half of the composite hollow part 4 is manufactured using the lower mold 2.
In the first step shown in FIG. 3, the outer skin A12 made of the separator 11 and the CFRP cloth material is alternately inserted along the concave cross section of the lower mold 2 and laminated. The separator 11 here is a release paper that is sandwiched between the outer skins in order to prevent the outer skins from coming into close contact with each other. A skin support jig 13 is set on the lower mold 2 in order to hold the folded portion 12a of the outer skin A12.
The separator 11 is sandwiched only in the folded portion 12a and has a function of preventing the laminated outer skin A12 from sticking to the folded portion 12a. Therefore, after the outer skin A12 is folded back in a process described later, the separator 11 is unnecessary and removed.
[0024]
In the second step shown in FIG. 4, an outer skin B14 made of a CFRP unidirectional material previously laminated on another flat base is set on the bottom of the lower mold 2.
[0025]
In the third step shown in FIG. 5, separators 15 and inner skins 16 made of CFRP cloth material are alternately laminated on outer skins A and B. The separator 15 used here is also inserted only into the folded portion 16a of the inner skin 16, and has a function of preventing the laminated inner skins 16 from sticking to each other. Therefore, when the inner skin 16 is folded back in a process described later, the separator 15 becomes unnecessary and is removed.
[0026]
In the fourth step shown in FIG. 6, a tedla film (registered trademark) 17 is applied as a release paper and pasted to the vertical wall and the corner R portion of the inner skin 16 laminated in the previous step. Since the inner skin 16 of the vertical wall and the corner R portion is easily buckled at the time of curing, a vapor soap described later may be involved due to this buckling. Further, when the leached resin enters the seam of the vapor soap, the vapor soap and the inner skin 16 adhere to each other, making it difficult to remove after curing, and the vapor soap remains in the product as foreign matter. The attachment of the tedlar film 17 in this step is to perform edge cutting in order to prevent such foreign matter from remaining in the product.
[0027]
In the fifth step shown in FIG. 7, vapor soap 5 is applied as an auxiliary material for mold release and ventilation, and is adhered onto the inner skin 16 and the tedlar film 17 along the concave cross section. This vapor soap 5 is an auxiliary material in which a release film and a ventilation cloth are integrated, and is used by attaching the release film side to the inner skin 16 surface, and is extracted after curing. In addition, the length for the overlap with the thing attached by a post process is added to the vapor soap 5.
[0028]
In the sixth step shown in FIG. 8, the core 7 and the tubing film 6 are set on the vapor soap 5 of the lower mold 2. The core 7 used here is made of foamed urethane, and is previously processed according to the shape of the hollow portion 4a. The tubing film 6 is a tube-like nylon bag, and an inexpensive commercially available one can be used.
In this step, the foamed urethane core 7 is placed in the tubing film 6, and both are disposed on the bottom of the concave section of the lower mold 2. Thereafter, a leak check of the tubing film 6 is performed. In this leak check, vacuuming is performed after fixing both ends of the tubing film 6 with a sealing tape, and the presence or absence of a leak, that is, the presence or absence of tearing is confirmed. In addition, when it turns out that the tubing film 6 is torn, it is extremely difficult to exchange the tubing film 6 after a process of combining the lower mold 2 and the upper mold 3 described later together.
[0029]
In the seventh step shown in FIG. 9, the same vapor soap 5 as that in the fifth step is applied and pasted on the upper surface side of the core 7 put in the tubing film 6. Then, the seam between the lower surface side attached in the fifth step and the upper surface side attached in this step is overlapped, whereby the core 7 in the tubing film 6 is wrapped in the vapor soap 5.
[0030]
In the eighth step shown in FIG. 10, the inner skin 16 is folded back toward the core 7, and the seam is overlapped on the upper surface side and laminated. At this time, the left and right inner skins 16 are alternately laminated one by one, and the separators 15 sandwiched between the inner skins are sequentially unnecessary and removed. When the eighth step is finished, the work on the upper side of the composite hollow part 4 is finished for the time being.
[0031]
Next, the production of the other half of the composite member hollow part 4 using the upper mold 3 will be described.
In the ninth step shown in FIG. 11, after the separator 18 is disposed along the surface of the upper die 3, an outer skin C19 made of a CFRP unidirectional material is set on the bottom of the die.
Like the outer skin B14 set on the lower mold 2 in the second step, the outer skin C19 is laminated in advance on a separate flat base. Through this step, the small part and the outer skin C19 are placed in the normal position. It becomes a set. The purpose of using the dummy jig is that the outer skin (CFRP cloth material) has already been faulted in the lower mold, so it is not necessary to stack the outer skin on the upper mold. is necessary. Set the outer skin (CFRP unidirectional material) and small parts separately (on the flat base) and small parts on the dummy jig, and adjust to the proper position. Without this dummy jig, the position of the outer skin (CFRP unidirectional material) and small parts cannot be determined.
[0032]
Thereafter, the lower die 2 and the upper die 3 are combined, but before that, in the tenth step shown in FIG. 12, the small part and the outer skin C19 set at the regular positions in the ninth step described above are It is removed from the upper mold 3 and set on the finished product in the eighth step shown in FIG. The release from the upper mold 3 of the outer skin C19 can be easily performed by the presence of the separator 18.
Then, the folded portions 12a of the outer skin A12 held by the skin support jig 13 are folded one by one on the left and right outer skins C19, and the joints are butt jointed. At this time, since the separators 11 exist between the folded portions 12a of the outer skins A12, the separators 11 can be easily separated. After the folded portions 12a are separated, the separators 11 become unnecessary and are sequentially removed.
[0033]
When the folding and stacking of the outer skin A12 are completed in this way, subsequently, in the eleventh step shown in FIG. 13, after setting the auxiliary upper mold 3a to the lower mold 2, the upper mold 3 is combined. As a result, the core 7, the tubing film 6, the inner skin 16, the outer skin A 12, the outer skin B 14, the outer skin C 19 and the like are all housed in the mold 1.
[0034]
And the shaping | molding die 1 mentioned above is put in the outer periphery bag 20 in the 12th process shown in FIG. As this outer peripheral bag 20, a commercially available tubular nylon bag that can be obtained at low cost can be used. The outer peripheral bag 20 is sealed with the tubing film 6 and the sealant tape, and then the inside is evacuated.
[0035]
The mold 1 that has been evacuated to a predetermined pressure is placed in a heating furnace (not shown) such as an autoclave (heating / pressure molding / curing furnace). In the heating furnace, the composite material composed of the outer skins A, B, C and the inner skin is cured by maintaining a predetermined temperature and heating for a predetermined time. At this time, a predetermined pressure and a vacuum pressure are applied.
[0036]
When the curing of the composite material is completed by heating in the heating furnace, the debugging operation of the mold 1 taken out from the heating furnace is started.
In this debugging operation, as shown in FIG. 15, only the outer peripheral bag 20 is first removed. At this time, sufficient care must be taken not to damage the tubing film 6 sealed with the sealant tape.
Subsequently, only the tubing film 6 is evacuated again to separate the tubing film 6 from the vapor soap 5 on the outer peripheral side.
Then, while continuing this evacuation, the solvent is poured into the tubing film 6 from the opposite side, and the evacuation is stopped after confirming that the solvent has permeated the whole. FIG. 16 is a conceptual diagram showing how the solvent 21 permeates while evacuating. The foamed urethane core 7 in the mold 1 is entirely immersed in the solvent 21 in the tubing film 6. .
In addition, as a solvent used here, methyl ethyl ketone (MEK) etc. are suitable.
[0037]
When the core 7 in the tubing film 6 soaked in the solvent is left as it is for a predetermined time, the urethane foam is dissolved to form a jelly. The core 7 made of urethane foam heated at the time of curing shrinks to a certain extent when exposed to a high temperature of the heating temperature, but a hollow shape portion whose cross-sectional shape is complicated and narrowly changed by this degree of shrinkage. It is extremely difficult to extract from.
Therefore, as described above, it becomes necessary to dissolve the foamed urethane core 7 in a jelly form with a solvent, and the jelly-shaped core 7 in the tubing film 6 is freely deformed. It can be easily extracted from the hollow portion.
[0038]
After removing the tubing film 6 and the core 7, the auxiliary upper mold 3 a and the upper mold 3 are removed, and the composite hollow part 4 is removed from the lower mold 2. And if the vapor soap 5 of the submaterial remaining in the hollow part 4a is extracted, shaping | molding of the composite material hollow component 4 will be completed. In addition, after thermoforming, the tedla film 17 is left as a foreign substance inside.
[0039]
By forming the composite hollow part 4 by such a method and procedure, the hollow part 4a has a complicated shape, a complicated change in cross-sectional shape, and a narrow cross-sectional part. can do. In other words, the core removal after molding, which was a problem in the molding method using the conventional silicon bag, was solved by immersing foamed urethane in methyl ethyl ketone and dissolving it in a jelly shape that can be deformed quite freely. . Therefore, the jelly-like core can pass by free deformation even if there is a narrow cross-sectional shape part in the middle of being extracted, and also can sufficiently follow changes in the bent part and cross-sectional shape, The extraction of the core does not limit the shape of the hollow portion 4a.
In addition, since the core 7 which became jelly shape is extracted from the hollow part 4a in the state accommodated in the tubing film 6, the handling after extraction is very easy.
[0040]
Further, since there is a vapor soap 5 between the tubing film 6 and the inner surface of the hollow portion 4a for easy release, the tubing film 6 is easily separated and broken at the time of extraction. There is no. The vapor soap 5 is selected to satisfy the conditions such as the heating temperature at the time of curing, releasability and air permeability, but other sub-materials satisfying the conditions can also be adopted.
[0041]
And it is necessary to select the tubing film 6 that can withstand the heating temperature at the time of curing, but if it is the curing temperature of the currently used composite material, it is generally a commercially available tube shape. There is no particular problem with nylon bags. Therefore, it is not only easy to procure but also inexpensive, which is advantageous for reducing the manufacturing cost of the composite hollow part 4. In addition, since a dedicated jig necessary for production of a conventional silicon bag is not necessary, this is also advantageous for cost reduction.
[0042]
【The invention's effect】
The method for molding a composite hollow part according to the present invention has the following effects.
(1) Since a tubular nylon bag can be purchased and used at a low price, the cost can be reduced as compared with a silicon bag using a dedicated jig.
(2) The internal shape and height of the hollow portion can be used for almost any shape because it is molded using a core formed by processing foamed urethane. That is, it is possible to cope with not only a modified cross section whose cross-sectional shape changes in the longitudinal direction but also a cross section whose cross-sectional shape changes complicatedly or narrowly. Of course, it can be adopted as a method of forming a composite hollow part having a simple cross-sectional shape such as the same cross-section.
(3) Sub-materials and cores after heat molding can be easily removed, so they do not remain as foreign matter in the product.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing one embodiment of a method for forming a composite hollow part according to the present invention.
2 shows an example of the shape of a composite hollow part molded by the molding method of FIG. 1, (a) is a perspective view showing the overall shape, and (b) is along the AA line of (a). It is sectional drawing.
FIG. 3 is an explanatory view showing a first step of a method for forming a composite hollow part according to the present invention.
FIG. 4 is an explanatory view showing a second step of the method for forming a composite hollow part according to the present invention.
FIG. 5 is an explanatory view showing a third step of the method for forming a composite hollow part according to the present invention.
FIG. 6 is an explanatory view showing a fourth step of the method for forming a composite hollow part according to the present invention.
FIG. 7 is an explanatory view showing a fifth step of the method for forming a composite hollow part according to the present invention.
FIG. 8 is an explanatory view showing a sixth step of the method for forming a composite hollow part according to the present invention.
FIG. 9 is an explanatory view showing a seventh step of the method for forming a composite hollow part according to the present invention.
FIG. 10 is an explanatory view showing an eighth step of the method for forming a composite hollow part according to the present invention.
FIG. 11 is an explanatory view showing a ninth step of the method for forming a composite hollow part according to the present invention.
FIG. 12 is an explanatory view showing a tenth step of the method for forming a composite hollow part according to the present invention.
FIG. 13 is an explanatory view showing an eleventh step of the method for forming a composite hollow part according to the present invention.
FIG. 14 is an explanatory view showing a twelfth step of the method for forming a composite hollow part according to the present invention.
FIG. 15 is an explanatory view showing a debugging operation of the method for forming a composite hollow part according to the present invention.
FIG. 16 is a conceptual diagram showing a state of vacuuming and solvent pouring.
FIG. 17 is an explanatory view of a conventional method of molding a composite hollow part.
18 is a perspective view showing an example of the shape of a composite hollow part molded by the conventional molding method of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mold 2 Lower mold 3 Upper mold 4 Composite material hollow part 4a Hollow part 5 Mold release, ventilation member (vapor soap)
6 Tubing film 7 Core 12 Outer skin A
14 Outer skin B
16 Inner skin 17 Tedra film 19 Outer skin C
20 Peripheral bag 21 Solvent (Methyl ethyl ketone)

Claims (3)

A molding method for vacuum / pressurizing / heating molding a composite hollow part having a hollow part,
A soluble member is used as the core material for forming the shape of the hollow portion, and the core is put in a tubing film and set at a predetermined position in a mold, and vacuum / pressurization / heating molding is performed and combined. After the molding and curing of the hollow material part is completed, a solvent is poured into the tubing film to dissolve the core, and the jelly-shaped core is pulled out from the hollow portion together with the tubing film ,
A release / breathing member in which a release film and a ventilation cloth are integrated is interposed between the inner surface of the hollow portion and the tubing film, and further, the vertical wall portion and the corner R portion of the hollow portion and the A method for forming a composite hollow part, wherein a release paper is interposed between the release / venting member .   The method for forming a composite hollow part according to claim 1, wherein the soluble member is foamed urethane, and the solvent is methyl ethyl ketone.   3. The method of forming a composite hollow part according to claim 1, wherein the tubing film is a tubular nylon bag.

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