Preform manufacturing method

Abstract

To improve the concerns of conventional preform manufacturing methods, such as increased preform thickness and uneven strength distribution.SOLUTION: In manufacturing preform P of an FRP molded product, a fiber tape 1 with reinforcing fibers oriented in the longitudinal direction and a frame jig 2 that surrounds the contour shape of the molded product are used, the fiber tape 1 is arranged parallel to and stacked on the frame jig 2 to cover the inner area to form a fiber-laminated body S, and the frame jig 2 and the fiber-laminated laminated body S are moved to a forming die 60 to form the fiber laminated body S. The preform P having uniform strength distribution and good shape accuracy is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a preform used to manufacture a preform for an FRP molded product, and further to a preform manufactured by the method, a frame-shaped jig used in the method, and a method for manufacturing an FRP molded product. [Background technology]

[0002] A conventional method for manufacturing a preform is described, for example, in Patent Document 1. The preform manufacturing method described in Patent Document 1 manufactures a preform by arranging reinforcing fiber bundles in one direction at predetermined positions on a sheet-like base substrate and adhering them. The sheet-like base substrate is made of a nonwoven fabric or mat and has many slits formed therein that extend in a direction intersecting the reinforcing fiber bundles, which allows it to be easily deformed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-159099 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional preform manufacturing method described above, a sheet-like base material is used, which increases the thickness of the preform and makes the base material resin-rich, which may result in uneven strength distribution, and solving such problems has been an issue. Also, in the conventional manufacturing method, the base material needs to be cut to fit the shape of the preform, so the positioning criteria when arranging it in the shaping mold are unclear, which may affect the shape accuracy of the preform.

[0005] The present invention has been made in view of the above-mentioned conventional problems, and aims to provide a method for manufacturing a preform that can obtain a preform having a uniform strength distribution and good shape accuracy. [Means for solving the problem]

[0006] The preform manufacturing method according to the present invention uses a fiber tape in which reinforcing fibers are oriented in the longitudinal direction and a frame-shaped jig that surrounds the contour shape of the molded product when manufacturing a preform for an FRP molded product. The preform manufacturing method then involves placing the fiber tape on the frame-shaped jig so as to cover the inner region of the frame-shaped jig. each other The fiber tapes are arranged in parallel and stacked to form a fiber laminate, and the frame-shaped jig and the fiber laminate are moved to a shaping mold to shape the fiber laminate. [Effects of the Invention]

[0007] The preform manufacturing method of the present invention forms a fiber laminate using only fiber tapes arranged in parallel and stacked on a frame-shaped jig, resulting in a uniform strength distribution.Furthermore, since the fiber laminate is placed in a shaping mold together with the frame-shaped jig and shaped, it is possible to position it accurately relative to the shaping mold, and a preform with good shape accuracy can be obtained. [Brief explanation of the drawings]

[0008] [Figure 1] 1A is a perspective view illustrating one embodiment of a method for producing a preform according to the present invention, FIG. 1B is a cross-sectional view, and FIG. 1C is a plan view of a fiber tape. [Figure 2] 2 is an exploded perspective view of the frame-shaped jig and tape supporters shown in FIG. 1. FIG. [Figure 3] 1A is a front view illustrating a tape head, and FIG. 1B is a side view illustrating the tape head. [Figure 4] 1A is a cross-sectional view showing a state in which a frame-shaped jig and a fiber laminate are set in a shaping mold, and FIG. 1B is a cross-sectional view showing a state in which the fiber laminate is being shaped. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of a method for manufacturing a preform according to the present invention will be described with reference to the drawings. The following embodiment also describes an embodiment of a preform manufactured by the method, a frame-shaped jig used in the method, and a method for manufacturing an FRP molded product.

[0010] The preform manufacturing method for producing a preform for an FRP molded product uses a fiber tape 1 with reinforcing fibers oriented in the longitudinal direction and a frame-shaped jig 2 that surrounds the outline shape of the molded product, as shown in Figure 1.

[0011] As shown in Fig. 1(C), the fiber tape 1 is made by flattening a bundle of reinforcing fibers such as continuous carbon fibers and fixing them with stitches 1A. In a more preferred embodiment, this fiber tape 1 has a binder applied to at least one surface.

[0012] The frame-shaped jig 2 can be molded from metal, plastic, etc. The frame-shaped jig 2 is formed into various shapes according to the contour of the molded product, but in the illustrated example, it has a rectangular shape with one of the long sides bent inward at the center to form a trapezoid.

[0013] The frame-shaped jig 2 is used as part of the shaping mold when shaping the fiber laminate, which will be described later. Therefore, the frame-shaped jig 2 has an inner area that is slightly larger than the contour shape of the molded product, taking into account the amount of fiber laminate that will be drawn into the shaping mold, and has a downwardly sloping inclined surface 2A on the inside so that the fiber laminate can smoothly deform along the shaping mold. The frame-shaped jig 2 is placed on a substrate 3 shown in Fig. 1(A) and is positioned by a positioning pin 4 shown in Fig. 1(B).

[0014] 1 and 2, in the preform manufacturing method, a thin tape supporter 5 is placed in the inner region of the frame-shaped jig 2. The material of the tape supporter 5 is not limited, and the tape supporter 5 has a thickness dimension at least equivalent to the thickness of the frame-shaped jig 2.

[0015] Furthermore, in the preform manufacturing method, double-sided adhesive tapes 6 are arranged on the upper surface of the frame-shaped jig 2 as fastening parts for positioning both ends of the fiber tape 1. The double-sided adhesive tape 6 has different adhesive strengths on one side and the other side. In this embodiment, the double-sided adhesive tapes 6 are arranged along sides of the frame-shaped jig 2 that intersect with the longitudinal direction of the fiber tape 1, i.e., along both short sides of the rectangular part of the frame-shaped jig 2 and both oblique sides of the trapezoidal part. These double-sided adhesive tapes 6 are attached to the frame-shaped jig 2 with the side with the greater adhesive strength facing up.

[0016] In the preform manufacturing method, a tape head device 10 shown in Fig. 1(A) and Fig. 3 can be used when arranging the fiber tape 1 and the double-sided adhesive tape 6. The tape head device 10 moves in a fixed direction while individually paying out the fiber tape 1 and the double-sided adhesive tape 6, and presses them downward with a pressure roller 10A. This tape head device 10 can be used, for example, by being attached to a multi-axis control type work robot.

[0017] The illustrated tape head device 10 also includes a heater 10B that uses infrared rays or the like to heat the unwound fiber tape 1. As described above, when a binder is applied to at least one side of the fiber tape 1, the lower or upper fiber tape 1, or the upper and lower fiber tapes 1, are heated to melt the binder, and the upper and lower fiber tapes 1 are pressed by the pressure roller 10A to bond the upper and lower fiber tapes 1 together.

[0018] The method for manufacturing the preform involves positioning the frame-shaped jig 2 on the base 3 as described above, arranging the tape supporter 5 and the double-sided adhesive tape 6, and then arranging the fiber tape 1 in parallel to the frame-shaped jig 2 so as to cover its inner region as shown in Figure 1(A), and stacking the fiber tape 1 to form the fiber laminate S shown in Figure 1(B).

[0019] 1(A) shows only a portion of the fiber tape 1, but in reality, the fiber tapes 1 are arranged so as to cover the entire inside of the frame-shaped jig 2, and the desired number of sheets are stacked. At this time, the tape supporter 5 prevents the fiber tapes 1 from sagging inside the frame-shaped jig 2 due to their own weight, thereby maintaining the shape of the fiber laminate S.

[0020] Next, in the method for manufacturing the preform, the fiber laminate S is moved together with the frame-shaped jig 2 from the base 3 and set in the shaping mold 60 shown in Fig. 4(A). At this time, the fiber laminate S can maintain its shape by itself and the frame-shaped jig 2, so it can be easily moved together with the frame-shaped jig 2.

[0021] The illustrated shaping mold 60 includes a fixed lower mold 60L and an upper mold 60U that is movable up and down. The lower mold 60L has a flat concave molding space 60S, while the upper mold 60U has a flat convex shape corresponding to the molding space 60S. The fiber laminate S is positioned on the upper surface of the lower mold 60L together with the frame-shaped jig 2.

[0022] Thereafter, in the preform manufacturing method, the upper die 60U is lowered in the shaping mold 60, and as shown in Fig. 4(B), the fiber laminate S is pressed between the upper die 60U and the lower die 60L to form a three-dimensional preform P. At this time, in the preform manufacturing method, since the frame-shaped jig 2 has an inner region larger than the outline shape of the molded article and an inner inclined surface 2A, the fiber laminate S is smoothly deformed and the central main portion is shaped.

[0023] Moreover, in the preform manufacturing method, a double-sided adhesive tape 6 having different adhesive strengths on one side and the other side is used, and the side with the stronger adhesive strength is placed on the upper side, i.e., on the fiber tape 1 side. This prevents the double-sided adhesive tape 6 from peeling off from the frame jig 2 due to the pressure applied when shaping the fiber laminate S, which would cause resistance to shaping. The peripheral portion of the fiber laminate S where the double-sided adhesive tape 6 is attached is cut off in a later process.

[0024] The preform P shaped as described above is then subjected to RTM (Resin Transfer Molding) molding. That is, the preform P is impregnated with a thermosetting resin, heated, and pressurized to become a molded FRP product.

[0025] In this way, the preform manufacturing method forms the fiber laminate S using only fiber tapes 1 arranged in parallel and stacked on the frame-shaped jig 2, resulting in a uniform strength distribution. Furthermore, in the above preform manufacturing method, the fiber laminate S is placed together with the frame-shaped jig 2 in the shaping mold 60 and shaped, making it possible to position it with high precision relative to the shaping mold 60 and obtain a preform P with good shape precision.

[0026] In addition, the above-mentioned preform manufacturing method involves placing a frame-shaped jig 2 on a substrate 3 to form a fiber laminate S, and then moving the frame-shaped jig 2 and the fiber laminate S from the substrate 3 to place them in a shaping mold 60, which makes the work of forming and moving the fiber laminate S easy, prevents the fiber laminate S from losing its shape during movement, and contributes to further improving the shape accuracy.

[0027] Furthermore, in the above-mentioned method for producing a preform, both ends of the fiber tape 1 are positioned on the frame-shaped jig 2 using double-sided adhesive tape 6, with the surface with greater adhesive force facing upward. As a result, in the above-mentioned method for producing a preform, the fiber tape 1 can be positioned relatively inexpensively, easily, and reliably, and during shaping, the double-sided adhesive tape 6 adheres to the portion that will be cut out later, so there is no need for a peeling step, and the tape does not remain as a foreign substance on the preform P or the molded product.

[0028] Furthermore, in the above-mentioned preform manufacturing method, a frame-shaped jig 2 is placed on a substrate 3, and a tape supporter 5 is placed in the inner area of ​​the frame-shaped jig 2 to form a fiber laminate S, thereby preventing the fiber tape 1 from sagging and maintaining the shape of the fiber laminate S.

[0029] Furthermore, the above-mentioned preform manufacturing method uses fiber tape 1 with a binder applied to at least one side, and after arranging the first layer of fiber tape 1 in a frame-shaped jig 2, for the second layer and thereafter, the fiber tape 1 is heated and the upper and lower fiber tapes 1 are bonded together with the binder. In this way, the above-mentioned preform manufacturing method can obtain a fiber laminate S in which the fiber tapes 1 are bonded to each other, which more reliably prevents the fiber laminate S from losing its shape and also realizes further improvement in the shape accuracy of the preform P and molded products.

[0030] Furthermore, according to the above-mentioned preform manufacturing method, the upper and lower fiber tapes 1 are bonded together with a binder, so it is possible to arrange the upper layer fiber tape 1 between adjacent fiber tapes 1 in the lower layer, and it is also possible to arrange the upper layer fiber tape 1 in a different direction from the lower layer fiber tape 1 to adjust the orientation of the reinforcing fibers.

[0031] Furthermore, in the above-mentioned preform manufacturing method, by using a tape head device 10, the placement of at least one of the fiber tape 1 and the double-sided adhesive tape 6 can be automated, thereby improving placement accuracy and shortening cycle time.

[0032] Furthermore, the preform P produced by the above-described preform production method has a uniform distribution of reinforcing fibers and good shape precision, which can contribute to improving the quality of FRP molded products.

[0033] Furthermore, the frame-shaped jig 2 used in the above-mentioned method for producing a preform can arrange and position the fiber tape 1 with a relatively simple structure, making it possible to form the fiber laminate S with high precision and easily handle the work of moving and positioning the fiber laminate S relative to the shaping mold 60. In addition to the double-sided adhesive tape 6, the fastening part to be placed on the upper surface of the frame-shaped jig 2 may be any part that does not provide resistance during shaping, and may be a pin or cutting blade that penetrates between the reinforcing fibers of the fiber tape 1.

[0034] Furthermore, according to the method for manufacturing an FRP molded product obtained by RTM molding the above preform P, it is possible to provide a high-quality FRP molded product with uniform strength distribution and excellent shape precision.

[0035] The configurations of the preform manufacturing method, preform, frame-shaped jig, and FRP molded product manufacturing method according to the present invention are not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0036] 1 Fiber tape 2 Frame-shaped jig 3. Circuit Board 5 Tape Supporter 6 double-sided adhesive tape 10 Tape head device 60 Shaping mold P Preform S Fiber laminate

Claims

1. When manufacturing preforms for FRP molded products, A fiber tape in which reinforcing fibers are oriented in the longitudinal direction and a frame-shaped jig that surrounds the contour shape of the molded product are used, The fiber tapes are arranged parallel to each other in the frame-shaped jig so as to cover the inner region thereof, and the fiber tapes are stacked to form a fiber laminate; A method for manufacturing a preform, characterized in that the frame-shaped jig and the fiber laminate are moved to a shaping mold to shape the fiber laminate.

2. The frame-shaped jig is placed on a substrate to form the fiber laminate; The method for manufacturing a preform according to claim 1, wherein the frame-shaped jig and the fiber laminate are moved from above the substrate and placed in the shaping mold.

3. Using double-sided adhesive tape with different adhesive strengths on one side and the other side, 3. The method for manufacturing a preform according to claim 1, wherein the double-sided adhesive tape is placed on the frame-shaped jig with the surface with greater adhesive strength facing up, and both ends of the fiber tape are positioned by the double-sided adhesive tape.

4. The method for manufacturing a preform according to any one of claims 1 to 3, characterized in that the frame-shaped jig is placed on a substrate, and a plate-shaped tape supporter is placed in an inner area of ​​the frame-shaped jig to form the fiber laminate.

5. A binder is applied to at least one surface of the fiber tape, The method for manufacturing a preform according to any one of claims 1 to 4, characterized in that after a first layer of the fiber tape is arranged in the frame-shaped jig, in the second layer and thereafter, the fiber tape is heated and the upper and lower fiber tapes are bonded to each other with the binder.

6. 4. The method for manufacturing a preform according to claim 3, further comprising using a tape head device that moves in a fixed direction while unwinding and pressing downward at least one of the fiber tape and the double-sided adhesive tape.

7. A jig used in the method for manufacturing the preform according to any one of claims 1 to 6, characterized in that the jig has a frame shape surrounding the contour shape of the molded product and has fastening portions on its upper surface for positioning both ends of the fiber tape.

8. A method for producing an FRP molded product, comprising RTM molding a preform produced by the method for producing a preform according to any one of claims 1 to 6.

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