JP5017040B2 - Preform manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to a preform manufacturing method and a manufacturing apparatus for manufacturing a preform by molding a prepreg in which reinforcing fibers are impregnated with an uncured resin.

As a method for producing a molded product of fiber reinforced resin, for example, a method of manufacturing a preform by molding a sheet-like prepreg in which a reinforcing fiber is impregnated with an uncured resin, and molding the preform is known. .
When manufacturing a preform, the peripheral part of a sheet-like prepreg may be bent according to the shape of the molded product to be produced. However, when the peripheral edge is bent, wrinkles may occur in the obtained preform. For example, when the peripheral edge of a polygonal sheet is bent, wrinkles are generated at the corners. When the prepreg is bent, the wrinkles occur because the prepreg is excessive with respect to a predetermined shape at the corner portion, and the excessive portion is folded.
Therefore, there is a case where a cut is formed in the prepreg and the vicinity on both sides of the cut is overlapped so that the excess portion does not overlap.
The work of superimposing the vicinity of both sides of the cut was performed manually, but the productivity is low by manual work. Therefore, Patent Document 1 proposes a method of using a plurality of molds and applying a molding machine to superimpose both sides of the cut.
Republished WO 2004/018186

However, in the method described in Patent Document 1, the number of steps required for manufacturing a preform increases, and thus the productivity cannot be sufficiently increased.
In addition, when a preform is produced by sandwiching a prepreg between a female mold and a male mold, wrinkles may occur in the resulting preform even if a cut is formed in the prepreg.
The present invention has been made in view of the above circumstances, and has high productivity in manufacturing a preform, and can be obtained even when a preform is manufactured by sandwiching a prepreg formed with a notch between a female mold and a male mold. An object of the present invention is to provide a preform manufacturing method and a manufacturing apparatus capable of suppressing wrinkles in a preform.

  As a result of investigation by the present inventors, when the prepreg is sandwiched between a female mold and a male mold, it has been found that the vicinity of both sides of the cut does not overlap with each other and wrinkles may occur. And based on the knowledge, it further examined and invented the following preform manufacturing method and manufacturing apparatus.

That is, this invention includes the following aspects.
[1] A method for manufacturing a preform, in which a sheet-like prepreg is cut and shaped on both sides thereof,
A preform characterized in that a prepreg is pressed into a female mold by a male mold while pressing the vicinity of one side of the prepreg against the male mold by a band-shaped or rod-shaped elastic member attached to the female mold. Manufacturing method.
[2] An apparatus for manufacturing a preform comprising a female mold and a male mold, wherein the both sides of the cut formed in the sheet-shaped prepreg are overlapped and shaped.
Production of a preform characterized in that, when a prepreg is pushed into a female mold by a male mold, a belt-like or bar-like elastic member is attached to the female mold to press the vicinity of one side of the prepreg against the male mold. apparatus.

  According to the preform manufacturing method and manufacturing apparatus of the present invention, the productivity of preform manufacturing is high, and even when a preform is manufactured by sandwiching a prepreg having a notch between a female mold and a female mold, Generation of wrinkles in the preform to be produced can be suppressed.

(Preform manufacturing equipment)
An embodiment of the preform manufacturing apparatus (hereinafter abbreviated as manufacturing apparatus) of the present invention will be described.
1 and 2 show a manufacturing apparatus according to this embodiment. The manufacturing apparatus 1 includes a female mold 10 and a male mold 20, and sandwiches a sheet-shaped prepreg 30 (see FIG. 3) in which a cut 32 is formed in a corner 31 between the female mold 10 and the male mold 20. The prepreg 30 is shaped to produce a preform.

  The female mold 10 in the present embodiment is a rectangular parallelepiped, and has a cavity 12 opened at the upper surface 11. The cavity 12 is a space in which both the opening 12a and the bottom surface 12b are substantially square, and the opening area gradually decreases from the opening 12a toward the bottom surface 12b.

  The male mold 20 moves up and down and fits into the cavity 12 of the female mold 10. The male mold 20 in the present embodiment example includes a body part 21 and a lower end part 22 positioned below the body part 21, and has a substantially square cut surface when cut in the horizontal direction. The area of the lower end portion 22 of the male mold 20 becomes smaller as it becomes the female mold 10 side. Specifically, the cut surface of the body portion 21 has the same shape as the opening portion 12 a of the cavity 12 of the female mold 10, and the bottom surface 22 a of the lower end portion 22 has the same shape as the bottom surface 12 b of the cavity 12 of the female mold 10. It has become.

Further, in the manufacturing apparatus 1 according to this embodiment, the belt-shaped elastic member 40 is attached to the female mold 10. Specifically, when the prepreg 30 is placed on the upper surface 11 of the female die 10, the elastic member 40 has a portion 33 (hereinafter, referred to as the following) of the prepreg 30 on one side of the notch 32, as shown in FIGS. 4 and 5. It is attached to the female die 10 so as to be disposed below the notch vicinity portion 33. In this embodiment, as shown in FIG. 3, four elastic members 40 are provided, two of which are in contact with one side (first side 35) of the prepreg 30 and the remaining two are It is in contact with the second side 36 opposite to the first side 35.
Further, the elastic member 40 is attached so that the tip thereof reaches the side surface of the descending male mold 20.
By attaching the elastic member 40 as described above, when the prepreg 30 is pushed into the female mold 10 by the male mold 20, the notch vicinity portion 33 of the prepreg 30 is pressed against the male mold 20. .

  Examples of the material constituting the elastic member 40 include a leaf spring made of a thin piece of metal or plastic.

The prepreg 30 shaped by the manufacturing apparatus 1 has a substantially square planar shape and is slightly larger than the opening 12a of the cavity 12 (see FIG. 3).
Examples of the reinforcing fibers constituting the prepreg 30 include carbon fibers, glass fibers, aramid fibers, high-strength polyester fibers, boron fibers, alumina fibers, silicon nitride fibers, and nylon fibers. Among these, carbon fiber is preferable because it is excellent in specific strength and specific elasticity.
Examples of the thermosetting resin include an epoxy resin, an unsaturated polyester resin, an acrylic resin, a vinyl ester resin, a phenol resin, and a benzoxazine resin. Among these, an epoxy resin is preferable because the strength after curing can be increased.
The prepreg 30 may contain various additives such as a curing agent, a release agent, a defoaming agent, an ultraviolet absorber, and a filler.
The form of the prepreg 30 may be a UD prepreg in which reinforcing fibers are aligned in one direction, or a woven prepreg in which reinforcing fibers are woven.

(Preform manufacturing method)
Next, an embodiment of a preform manufacturing method using the manufacturing apparatus 1 described above will be described.
In the manufacturing method according to this embodiment, first, the prepreg 30 is placed on the opening 12 a of the female mold 10. At that time, as shown in FIG. 3, the four corners of the prepreg 30 correspond to the four corners of the opening 12 a, and as shown in FIGS. 4 and 5, the elastic member 40 is under the notch vicinity portion 33 of the prepreg 30. The prepreg 30 is arranged so as to be positioned. Moreover, the prepreg 30 can be heated as needed.

  When heating, the heating temperature is preferably 40 to 80 ° C. If the heating temperature is 40 ° C. or higher, it can be easily formed into a predetermined preform shape, and if it is 80 ° C. or lower, the curable resin can be prevented from being cured during the manufacture of the preform.

Next, the male mold 20 is lowered and pushed into the female mold 10. As shown in FIG. 6, when the male mold 20 is lowered and the bottom surface 22 a of the male mold 20 presses the elastic member 40, the elastic member 40 presses the notch vicinity portion 33 of the prepreg 30 against the male mold 20. It becomes like this.
Next, the male mold 20 is further lowered while the elastic member 40 presses the notch vicinity portion 33 of the prepreg 30 against the male mold 20, and the prepreg 30 is sandwiched between the female mold 10 and the male mold 20 to form a predetermined preform shape. Shape it.

  The pressure during shaping is preferably 0.01 to 0.1 MPa. If the pressure is 0.01 MPa or more, it can be easily formed into a predetermined preform shape, and if it is 0.1 MPa or less, the production apparatus can be simplified.

Thereafter, the male mold 20 is raised, and the obtained preform is taken out from the cavity 12 of the female mold 10. After the preform is taken out from the female mold 10, the shape of the elastic member 40 returns to the original state, so that the notch vicinity portion 33 can be pressed against the male mold 20 again.
The preform thus manufactured is placed in a mold and heated to obtain a molded product made of fiber-reinforced resin having a predetermined shape.

In the manufacturing method using the manufacturing apparatus 1 described above, when the prepreg 30 is pushed into the female mold 10 by the male mold 20, the notch vicinity portion 33 of the prepreg 30 is pressed against the male mold 20 by the elastic member 40. The notch vicinity part 33 can be bent before the other notch vicinity part 34 (see FIG. 7). Thereafter, by sandwiching the prepreg 30 between the female mold 10 and the male mold 20 and bending the notch vicinity portion 34, the notch vicinity portion 34 can be overlapped with the notch vicinity portion 33 as shown in FIG. Therefore, according to this manufacturing method, even if the prepreg 30 in which the cut 32 is formed is sandwiched between the female mold 10 and the male mold 20, it is possible to prevent the cut vicinity portions 33 and 34 from colliding with each other and folding them. Generation of wrinkles can be suppressed.
Further, in this method, it is not necessary to use a plurality of female molds in the manufacture of the preform, and the number of steps can be reduced, so that productivity is high.

  The preform thus manufactured is placed in a mold and heated to obtain a molded product made of fiber-reinforced resin having a predetermined shape.

The present invention is not limited to the above-described embodiment example. For example, the shapes of the female mold and the male mold are not particularly limited, as long as the female mold has a cavity corresponding to the shape of the preform, and the male mold only needs to have a shape that fits into the cavity. The shape of the cut surface when the cavity is cut in the horizontal direction may be a triangular shape, a polygonal shape such as a square shape other than a square, a circular shape, an elliptical shape, a fan shape, or the like.
Further, the elastic member may be rod-shaped.
A plurality of sheet-like prepregs may be stacked. However, when stacking sheet-like prepregs, it is preferable to dispose the cuts 32, 32, 32 as shown in FIG. When arranged in this way, as shown in FIG. 10, the prepregs 30, 30, 30... Overlap with each other at the corners of the obtained preform so that local thickness does not occur. Therefore, strength reduction due to concentration of stress can be prevented, and generation of wrinkles of the preform can be further suppressed.

A unidirectional prepreg was obtained by heat impregnating an epoxy resin into a unidirectional material in which carbon fibers were aligned in one direction. Two prepregs were stacked to obtain a prepreg laminate. At that time, the prepreg was laminated so that the directions of the carbon fibers were alternately orthogonal.
Next, the prepreg laminate was cut into a substantially square shape, and wedge-shaped cuts were formed at the corners.

Next, the prepreg laminate in which the cuts are formed (hereinafter, the “prepreg laminate” is also referred to as “prepreg” for convenience of explanation) is formed on the opening 12a of the female mold 10 in the manufacturing apparatus 1 shown in FIGS. It was put on. At that time, as shown in FIG. 3, the four corners of the prepreg 30 correspond to the four corners of the opening 12a, and as shown in FIG. 4 and FIG. The prepreg 30 was arranged so that a certain leaf spring was located.
Further, three prepregs 30 having cuts 32 formed thereon were laminated on the prepreg 30. Also in this case, the prepreg 30 is arranged so that the leaf spring is located under the notch vicinity portion 33 of the prepreg 30 and the notches 32 of each prepreg 30 are sequentially shifted.

Next, after the laminated prepreg 30 was heated with an infrared heater, the male mold 20 was lowered and the prepreg 30 was pushed into the female mold 10. At this time, the notch vicinity portion 33 of each prepreg 30 was pressed against the male mold 20 by the leaf spring.
Next, the laminated prepreg 30 is sandwiched between the female mold 10 and the male mold 20, the portions other than the notch vicinity portion 33 of the prepreg 30 are bent, both sides of the notch 32 are overlapped, shaped, and molded. Got a renovation. Then, air was blown onto the female mold 10 and the male mold 20 to cool them, and then the male mold 20 was raised, and the obtained preform was taken out from the cavity 12 of the female mold 10.

  Next, the obtained preform was placed in a lower mold for compression molding, sandwiched between upper molds, and heated and pressed to obtain a molded product made of fiber reinforced resin.

  When the prepreg is pushed into the female mold by the male mold, the vicinity of the prepreg notch is pressed against the male mold by the leaf spring, so that the productivity of the preform production is high and the occurrence of wrinkles in the preform obtained is high. I was able to suppress it. Therefore, generation of wrinkles was also suppressed in the molded product obtained from this preform.

It is a top view which shows one embodiment of the manufacturing apparatus of the preform of this invention. It is a longitudinal cross-sectional view of the preform manufacturing apparatus of FIG. It is a figure explaining the cutting of a prepreg and arrangement | positioning of an elastic member. It is the top view to which the elastic member vicinity in FIG. 3 was expanded. It is II sectional drawing of FIG. It is a figure explaining the manufacturing method of the preform using the manufacturing apparatus of the preform of FIG. It is the figure which expanded the principal part of FIG. It is a figure which shows the state which accumulated the vicinity of the both sides of a notch of a prepreg. It is a figure which shows the form which piled up two or more prepregs. It is sectional drawing which shows the lamination | stacking state of the prepreg in a preform.

Explanation of symbols

1 Manufacturing equipment (Preform manufacturing equipment)
DESCRIPTION OF SYMBOLS 10 Female type | mold 11 Upper surface 12 Cavity 12a Opening part 12b Bottom face 20 Male type | mold 21 Body part 22 Lower end part 22a Bottom face 30 Pre-preg 31 Corner part 32 Notch 33, 34 Incision vicinity part 40 Elastic member

Claims (2)

A method for manufacturing a preform, in which a sheet-like prepreg is cut and shaped on both sides,
A preform characterized in that a prepreg is pressed into a female mold by a male mold while pressing the vicinity of one side of the prepreg against the male mold by a band-shaped or rod-shaped elastic member attached to the female mold. Manufacturing method. An apparatus for manufacturing a preform comprising a female mold and a male mold, wherein the both sides of a cut formed in a sheet-like prepreg are superimposed and shaped,
Production of a preform characterized in that, when a prepreg is pushed into a female mold by a male mold, a belt-like or bar-like elastic member is attached to the female mold to press the vicinity of one side of the prepreg against the male mold. apparatus.

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