JP4372384B2 - Preform manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reinforced fiber base preform used in an RTM (resin transfer molding) molding method of a fiber reinforced plastic (hereinafter abbreviated as FRP) member made of a reinforced carbon fiber and a matrix resin, such as an automobile or an aircraft. It relates to the manufacturing method.
[0002]
[Prior art]
Conventionally, CFRP using carbon fiber or glass fiber as a reinforcing fiber is lightweight and highly durable, so it is an ideal material for various components such as automobiles and airplanes. A so-called autoclave molding method, in which a laminate of tens of tens to hundreds of microns of prepreg, each of which is made of high toughness epoxy resin, is pressed and heated in an autoclave. It is common. However, since the prepreg is impregnated with resin around the reinforcing fibers, it is difficult to deform the prepreg because the fibers are fixed with the resin, and the prepreg is applied to a predetermined three-dimensional shape. There was a problem that it could not be shaped. For this reason, when manufacturing FRP aircraft and automobile parts having uneven three-dimensional shapes, a manufacturing method in which prepregs are cut and overlapped even with unevenness of several millimeters and joined in a patch shape. Therefore, a member made of a prepreg is not only heavier than expected, but also has a need to increase the safety factor of the joint portion, so that an aircraft member or an automobile member to which FRP can be applied. The member has a restriction that it is limited to a relatively flat shape.
[0003]
Furthermore, in the prepreg, the curing agent is mixed in the resin in advance, and the reaction gradually proceeds even at room temperature. Therefore, in order to delay the curing reaction of the prepreg resin, the prepreg is stored in a freezer and used every time. In addition, there was an uneconomical aspect of providing a thawing process.
[0004]
As a method for producing FRP that solves such problems in prepreg molding, a molding method called an RTM (resin transfer molding) method as described in US Pat. No. 5,281,388 has begun to attract attention. Complex FRP structures having a length of 10 m or more are being put into practical use.
[0005]
In this manufacturing method, a reinforced fiber base material made of a so-called dry continuous fiber woven fabric, which is pre-shaped into a predetermined shape and is not completely impregnated with resin, is placed on the mold, and the whole is a bug. After covering with a film or a mold, the bag film or the mold is evacuated, and a resin is injected to diffuse and impregnate the preform. US Pat. No. 5,427,725 The document discloses a technique related to a semi-cured preform using a tackifier.
[0006]
In RTM molding, since a preform is used in this way, a step of cutting an adhesive material called a prepreg is not required, so that a lightweight and economical FRP member can be manufactured.
[0007]
However, the production of a preform requires a process of shaping a one-dimensional or two-dimensional reinforcing fiber base such as a fiber or a fabric into a predetermined three-dimensional shape. And whether it can be manufactured efficiently or can be automated is the biggest issue affecting the future of RTM molding.
[0008]
Usually, the shaping process is performed by manually cutting a reinforcing fiber base material such as a cloth and deforming it manually or by joining the cloth together. A reinforcing fiber base is placed between the lower molds and directly sandwiched between the upper and lower molds. The reinforcing fiber base is forcibly shaped by the closing force of the mold, and the resin is placed in both molds. It seems that an automatic molding method for injecting sucrose has been attempted. However, in such a shaping method, the reinforcing fiber base material is torn or pinched in the mold, and a reproducible preform, or a highly reliable FRP molded product, is obtained. There is no actual situation.
[0009]
[Problems to be solved by the invention]
In light of the background of such FRP molding technology, the present invention is a lightweight and highly reliable method for molding FRP members such as aircraft and automobiles, in particular, a preform having a three-dimensional shape suitable for use in RTM molding, The present invention provides a method for producing a preform that can be produced with high accuracy and automatically, a preform produced by the method, and an FRP molded article produced using the preform.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following configuration. That is,
(1) In a preform manufacturing method in which a reinforcing fiber base is shaped into a three-dimensional shape using a shaping die having a three-dimensional shape. The reinforcing fiber base is composed of at least continuous fibers, The vibration of the vibrating body is transmitted to the reinforcing fiber base to vibrate the reinforcing fiber base, and at the same time, the reinforcing fiber base is vibrated for a time sufficient to shape the three-dimensional shape, thereby A method for producing a preform, comprising shaping a fiber substrate into a three-dimensional shape.
[0011]
(2) The method for manufacturing a preform according to (1), wherein the vibrating body is in direct contact with a reinforcing substrate.
[0012]
(3) In the above (1) or (2), a fixing agent is applied to the reinforcing fiber base material, and a temperature for forming the three-dimensional shape is equal to or higher than a glass transition temperature of the fixing agent. A method for producing the preform as described.
[0013]
(4) A sticking agent is applied to the reinforcing fiber base. The reinforcing fibers constituting the reinforcing fiber base are bonded to each other and the reinforcing fiber base is fixed or temporarily fixed. The amplitude to vibrate by the vibrating body is Reinforced fiber between The method for producing a preform according to any one of (1) to (3), wherein the amplitude is equal to or greater than an amplitude at which coupling is broken.
[0014]
(5) There are a plurality of locations where the reinforcing fiber substrate is vibrated, and at the plurality of locations, a difference is given to the vibration start time and / or end time. The preform manufacturing method in any one.
[0015]
(6) A part or all of the periphery of the reinforcing fiber base is fixed so as to have deformation resistance, and the preform according to any one of (1) to (5) is manufactured. Method.
[0016]
(7) There are a plurality of locations where the reinforcing fiber base is vibrated, and the amplitude and / or the frequency are varied at the plurality of locations, according to any one of (1) to (6), Method for manufacturing preform.
[0019]
(8) The vibrating body is temporarily and / or completely stopped during the manufacturing process. (7) The method for producing a preform according to any one of the above.
[0020]
(9) (1) to (1) above characterized in that the vibration frequency and amplitude of the vibrating body are changed. (8) The method for producing a preform according to any one of the above.
[0021]
(10) (1) to (1) above, wherein a sticking agent is applied during and / or after the preform manufacturing process to stabilize the form of the preform. (9) The method for producing a preform according to any one of the above.
[0022]
(11) The reinforcing fiber substrate is made of inorganic fibers (1) to (1) (10) The method for producing a preform according to any one of the above.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
For example, as shown in FIG. 1, the preform manufacturing method of the present invention includes a reinforcing fiber of an RTM molded product (FRP) on a shaping mold 1 having a predetermined three-dimensional shape with unevenness to be shaped. A reinforcing fiber base 2 such as a cloth shape is arranged, and vibrations from the vibrating body 3 are transmitted to the reinforcing fiber base 2 directly or indirectly to the reinforcing fiber base 2 to form the reinforcing fiber base 2 This is a method in which the reinforcing fiber base 2 is shaped into a predetermined three-dimensional shape by pressing the fiber base 2 in the direction of the shaping mold 1 with the shaping jig 4 while making the reinforcing fibers to be easily moved. .
[0026]
For example, when trying to shape between a shaping die and a shaping jig with only a pressing force without vibrating the cloth-like reinforcing fiber base material, the movement is caused by the frictional resistance between the reinforcing fiber bundles constituting the cloth. Fibers other than the necessary reinforcing fibers also move, and defects such as so-called misalignment and wrinkles are likely to occur.
[0027]
This defect remains in the molded body (composite) even after RTM molding, and becomes a source of deterioration of physical properties such as a starting point of crack generation. Furthermore, the reinforcing fibers are broken at the corners with unevenness, or bridging occurs at the stepped portions, and cannot be shaped into a predetermined shape.
[0028]
However, in the present invention, the fibers in the reinforcing fiber substrate vibrate so that the reinforcing fibers are in contact with each other. Not connected Because of the repeated touch, the friction between the fibers is small, and the fibers can move and slide with a slight pressing force. Then, it can be shaped into a predetermined shape by moving it in the required direction. That is, when the reinforcing fiber base 2 made of a plain weave cloth is shaped into the shaping mold shape on the shaping mold 1 having a trapezoidal cross section (convex shape) as shown in FIG. 2, the warp and weft constituting the cloth are formed. Of these, if only the warp 5 and the weft 6 straddling the convex part can be moved by an amount corresponding to the height of the convex part, trapezoidal shaping, A preform having a shape can be manufactured.
[0029]
FIG. 1 shows an example in which the shaping jig 4 is used as a means for pressing the reinforcing fiber base against the shaping mold. However, if the reinforcing fiber base 2 which is the concept of the present invention vibrates, the shaping is performed. Even if the reinforcing fiber base is pressed against the shaping mold 1 with a planar shaping mold instead of the shaping jig 4, the reinforcing fiber base 2 is changed to the shaping mold 1 with the vibrator 3 itself. It can be pressed. Further, the pressing may be performed by drawing the reinforcing fiber base 2 toward the shaping die 1 by sucking air from the shaping die 1 side instead of the shaping jig 4.
[0030]
As will be described later, the vibrating body 3 serves to vibrate the reinforcing fiber base 2, and even if it is in direct contact with the reinforcing fiber base 2 to vibrate, it vibrates indirectly via a jig or the like. It can be transmitted. As a way of contact, contact with the vibrating body by a point or a surface does not affect the gist of the present invention. Further, the vibration may be input from above the reinforcing fiber base 2 or may be input from the side. Moreover, even if the place to vibrate is one place or multiple places, it does not affect the gist of the present invention.
[0031]
In the present invention, since the fibers in the reinforcing fiber base are vibrated, the tackifier described in US Pat. No. 5,427,725, Agent, Sizing agent , Rhino A solid material made of a polymer material or the like applied to the fiber for the purpose of stabilizing the form of a base material called a ging agent or the like, or improving the adhesion to the resin. The dressing Even if it adheres, it is possible to shape the reinforcing fiber base into a predetermined shape without wrinkles or misalignment by gradually deforming the base while giving vibration for a sufficiently long time, A predetermined preform is obtained.
[0032]
As described above, the characteristic feature of the present invention is that, since the fiber vibrates, the movement of the fiber can be preformed without generating wrinkles or misalignment on the substrate. That is, when shaping is performed only with the pressing force, only the fibers near the pressed portion move and follow the three-dimensional shape, so there is no balance in the amount of fibers, and the missing portions of the fibers (so-called voids) Part) or wrinkles occur, but if the fiber is sufficiently vibrated as in the present invention, the fiber vibrates at the end of the base material other than the pressed part. The fibers at the end of the base material are moved so that the balance of the amount of fibers is matched, and shaping into a three-dimensional shape can be performed without generating missing fibers or wrinkles.
[0033]
Further, even when the substrate is partially fixed with a tackifier or the like, the fixed portion is detached by vibration, and the fibers can move.
[0034]
As will be described later, the preform formed by three-dimensionally shaping the carbon fiber fabric can be shaped without any scumming or wrinkles even at the corners with irregularities (see FIG. 6), and the features of the present invention are clearly visible. It has become.
[0035]
Hereinafter, preferred embodiments of the preform manufacturing method of the present invention will be described in detail with reference to FIG. 1 and FIG.
[0036]
First, the shaping mold 1 has a three-dimensional shape that is substantially close to the final shape when it becomes a FRP member, that is, a molding die used when FRP is molded using a preform. The material of the shaping mold is preferably made of a solid such as metal, wood, FRP, plastic, ceramic, or rubber so as not to be greatly deformed even when the reinforcing fiber substrate is pressed. For the purpose of fixing the shaped preform to some extent as described later, Dressing Considering the case of granting, etc. The dressing The shaping surface may be covered with a film-like material such as silicon or polyethylene, or may be subjected to a release treatment such as a silicon-based release agent so that the mold can be easily released. If the reinforcing fiber base is made of a plurality of fabrics and has a thickness of several millimeters, the amplitude of the vibrating body tends to increase, so the mold should have a sturdy structure so that it can withstand this vibration. It is preferable to keep it. Further, since the vibration of the reinforcing fiber base is transmitted to the mold, it is preferable to make the mold heavy so that the mold does not move due to vibration, or to fix it to the floor or the like with a bolt or the like. It is also possible to suppress the vibration and movement of the mold by placing a damping material such as rubber and ferrite around the shaping mold and the bottom surface.
[0037]
When the mold is made of a high-rigidity material such as metal or FRP, the mold also vibrates in response to vibration from the reinforcing fiber base, so the friction resistance between the mold and the reinforcing fiber base decreases, and the reinforcing fiber base It becomes easier to move on the mold, and shaping can be performed with higher accuracy without causing wrinkles on the reinforcing fiber base. In addition, the final shape of the shaping mold is often modified while checking the shaping status of the reinforcing fiber base, so it is easy to modify the shape, such as steel or aluminum, or wooden Those are preferred.
[0038]
Furthermore, when a form stabilizer such as a binder is applied to the reinforcing fiber base, it is also effective to heat the base with hot air or infrared rays. It is preferable to use a resin. At this time, the heating temperature can be monitored with a non-contact type thermometer, and the heating temperature is preferably equal to or higher than the glass transition temperature (so-called Tg) of the binder.
[0039]
Next, the reinforcing fiber substrate 2 is a part or all of the reinforcing fiber of the FRP of the final member. , It is a continuous fiber, and its form is a cross such as plain weave or twill, It may be a fabric such as a mesh, knit, non-woven fabric or mat. As reinforcing fibers, inorganic fibers such as glass fibers and carbon fibers, and organic fibers such as aramid fibers and polyethylene fibers can be used alone or in combination. However, as described later, the base material is vibrated more efficiently. For this purpose, at least inorganic fibers are preferably used in the reinforced substrate. Among inorganic fibers, carbon fiber is the most preferable reinforcing fiber because it has the highest elastic modulus and is easy to transmit vibration, and therefore, the fibers slip and move more easily.
[0040]
Among the cloth-like materials, since the cloth base material is not bundled with fibers, only one yarn bundle (for example, warp yarn in the case of plain weave) constituting the woven fabric is vibrated, so that other Since fibers (wefts and adjacent warps) can be pulled out without being moved, this is a preferred form that can be shaped without generating wrinkles or dullness during shaping. In addition, the cloth is used for the entire molded body. Boho It is a reinforcing fiber base material that can be covered in one, and is suitable for structural use. Among them, a cloth called a unidirectional woven fabric is particularly suitable for a structure because it has the same strength and fiber content as a prepreg.
[0042]
Further, the reinforcing fiber base material may be provided with a bundling agent made of a polymer such as a thermosetting or thermoplastic resin called a binder for the purpose of fiber flaking or base stability of the base material. When the amount of binder attached is large, it is possible to increase the amplitude of the vibrating body, which will be described later, or to slow down the deformation speed of the base material, to make the vibration time long enough, and to gradually shape the base material. It is effective. Moreover, it is possible to soften the binder by heating to facilitate the deformation, or conversely, to cool the fibers at specific locations by cooling. In addition, as mentioned above, in the case of a binder made of a polymer, the heating temperature is preferably not less than the glass transition temperature. Moreover, it is preferable that the shaping speed is a speed that does not cause wrinkles or leakage.
[0043]
In addition, after shaping, in order to fix the shape of the preform, Dressing It is also preferable to give. Specifically, it is described in US Pat. No. 5,427,725. Dressing and , Glue material can be used. Solid Dressing The criterion for selection is to select a material that does not lower the physical properties of the matrix resin of FRP, and it is preferable to limit the amount of adhesion to a range that does not affect the physical properties and to a range that does not greatly increase the flow resistance of the resin. Specifically, the adhesion amount is 1 0% by weight The following are appropriate:
[0044]
The reinforcing fiber base material may be a single body, or may be a stack of a plurality of fabric-like materials or stitched fabrics, but may be a splice shape.
[0045]
The reinforcing fiber base is arranged on the shaping mold, but it is important that the necessary area of the reinforcing fiber base is larger than the surface area of the shaping mold. It is preferable to cut into a size of about 1.1 to 1.5 times the surface area of the shaping mold. It is also preferable to raise a paper pattern in which the tertiary shape of the shaping mold is developed and to form a reinforcing fiber base having a shape in which a paste margin is added to the shape of the paper pattern because the material yield can be improved. In addition, when an automatic machine is used for cutting the reinforcing fiber base material, the material yield can be further improved. Moreover, as shown in FIG. 4, it is also preferable to arrange a frame 7 around the reinforcing fiber base 2 at the time of shaping, and to fix a part or all of the periphery of the fiber reinforced base so as not to move. . By doing so, it is possible to adjust the movement of the entire base material due to friction between the reinforcing fiber base material 2 and the frame 7 or to take measures to fix the fibers and reference lines that are not desired to be moved. it can. Further, it is possible to suppress the movement due to gravity or wind force when tilting. Instead of using the frame 7, the peripheral part of the reinforcing fiber base is sewed, or the fiber and its periphery that you do not want to move with resin or adhesive tape are fixed to improve the efficiency and accuracy of the shaping operation. Improvement is also one embodiment of the present invention.
[0046]
Next, the so-called vibrator, vibrator, vibrator or the like can be adopted as the vibrator 3 of the present invention, but it is particularly limited as long as the vibration can vibrate the reinforcing fiber base. The electric type and the pneumatic type are widely known. For example, vibration motor KM25-2P, OH type, CH type, BH type, D25DS, D28FP manufactured by Exen Corporation, and an electric pneumatic tool “turbo lap” manufactured by OHT are available.
[0047]
As shown in FIGS. 3 and 7, the vibration of the vibrating body is transmitted between the vibrating body 3 and the reinforcing fiber base 2 by using a film or a roller even when the vibrating body 3 is brought into direct contact with the reinforcing fiber base 2. It is possible to go indirectly through such as. It is preferable to directly contact the vibrating body and the reinforcing fiber base material because vibration attenuation can be suppressed, so that a larger vibration can be transmitted to the reinforcing fiber. It is possible to use a plurality of vibrators at the same time or to use vibrators having different vibration characteristics.
[0048]
The reinforcing fiber base material vibrates due to vibration transmission from the vibrating body, and repeats contact and non-contact between fiber bundles and / or fiber single yarns, so that friction between fiber bundles and / or fiber single yarns is repeated. Decreases extremely, and in a non-contact state, the friction becomes zero. In this state, when a shaping force is applied to the reinforcing fiber base, the reinforcing fibers can move and deform without being constrained by other fibers, allowing shaping without wrinkles or slippery. It becomes.
[0049]
Moreover, as for a preferable vibration characteristic, an amplitude is 0.05-3 mm and a frequency is 50-2000 Hz. This is because if the amplitude is smaller than this range, the time required for shaping becomes longer, and if it is larger than this range, the accuracy control of the fiber position may be lowered. When the reinforcing fiber base is fixed or temporarily fixed with an adhesive, the amplitude is the adhesive. Reinforced fiber between It is preferable that the size is sufficient to break the bond. In addition, if it is not necessary to control the accuracy of fiber disturbance, the amplitude can be increased extremely or shaped without vibration. The amplitude and frequency can be determined in advance according to the desired accuracy. preferable. Also, if the frequency is less than this range, there is a demerit that the shaping time becomes longer, and if it exceeds this range, the reinforcing fiber Hurt This is because there is a possibility.
[0050]
As a more specific method of determining the amplitude, as shown in FIG. 5, the reinforcing fiber base 2 is fixed on the inclined mold 8 (FIG. 5 is described assuming 1/4 of the rotating drum). Then, a weight 9 of about 20 to 100 g is hung on one fiber bundle, the fiber bundle is vibrated while increasing the amplitude of the vibrating body, and the amplitude at the time when the weight starts to fall (move) naturally is obtained. It is effective to obtain an amplitude 1.1 to 1.5 times larger than the actual amplitude during shaping. Of course, it is possible to determine the shaping conditions by directly adjusting the frequency and amplitude on the shaping mold without prior examination as in this method.
[0051]
As a force for shaping, a bar shape, a roller shape, or a spatula shape called a shaping jig, which has a three-dimensional shape equivalent to the shaping shape, that is, one of the so-called top and bottom shapes or the left and right shapes Even if it is a pressing jig, or the vibrating body itself, as long as it can suck air from the shaping mold side or add wind force in the shaping mold direction and press the reinforcing fiber substrate against the shaping mold, But it doesn't matter. Most preferably, the vibrating body itself is a shaping jig, so that the vibration can be transmitted most efficiently to the part to be deformed, and the amplitude and frequency of the vibrating body can be adjusted. This is because it is easy to control.
[0052]
In addition, the shaping jig is a preferable shaping method that not only presses the reinforcing fiber substrate monotonously in one direction but also presses it irregularly by increasing or decreasing the pressing force or sliding left and right. The most preferable method is a method in which the vibration body is moved along the mold to the position where the reinforcing fiber is most desired to be moved, and the strength is gradually pressed. In the case of using a plurality of jigs, it is preferable to make a time difference in the pressing operation of the jigs because the movement of the fibers can be performed more smoothly and better shaping is possible. Further, when a plurality of jigs are used, it is preferable to appropriately set the frequency and amplitude to different values for each jig.
[0053]
There is no need to use a single vibrating body or shaping jig. Select and use multiple vibrating bodies with different frequencies and amplitudes to match the amount of fiber movement required for the reinforcing fiber base. It is preferable to do. In addition, the vibrating body does not necessarily have to vibrate during shaping, but may change the frequency and amplitude, or stop the vibration to stop the movement of the base material. .
[0054]
In addition to the shaping jig, it is also possible to pin the base material, or to partially apply an adhesive or adhesive such as glue to prevent the base material from moving or deforming. Within the scope of the invention.
[0055]
After shaping, the reinforcing fiber base that has been shaped can be retained after being removed from the shaping mold. ) Is preferable. Examples of heat setting include a method of spraying thermoplastic resin powder or fibrous material in a base material, heating the base material above its melting point, and then cooling it. Of course, the fixing part does not have to be the entire base material, and may be a part of the base material. If the uneven corners are fixed, it is a preferable fixing method because it is difficult to cause misalignment or opening even if the preform is handled roughly roughly.
[0056]
The shaped preform is placed in a mold, and the resin is filled into the preform and cured by injecting the resin into the mold, thereby completing the composite. Since the preform according to the present invention has a predetermined shape, the preform is not stretched when placed in the mold, and the production efficiency is improved. In addition, since there is no misalignment or opening, the surface of the composite is smooth and uniform, so that not only the design properties are good, but also the mechanical properties are stable. It has the characteristics suitable for the member which is required.
[0057]
The preform shaping method is a preform manufacturing method suitable for RTM molding, but the same technique is called partially impregnated prepreg (see WO-00 / 27632 and WO-98 / 34979). ), A kind of prepreg partially impregnated with resin can be transformed into a three-dimensional shape by applying this vibration shaping technique. Furthermore, the shaping using the heating means can also be applied to ordinary prepregs.
[0058]
【Example】
Example 1
As a preliminary study, a plain weave cloth (5 strands in the longitudinal direction / 25 mm, 5 strands in the transverse direction / 25 mm, 5 g / 25 mm in the transverse direction, 200 g / m) m ² ) Was placed on a metal drum having a diameter of 0.9 m and a width of 400 mm, and the four corners were fixed with an adhesive tape. After that, a weight of 30 g is hung on one longitudinal strand in the center of the cross, and the strand is vibrated at 0.3 mm and a vibration frequency of 250 Hz with a vibrating body (OHT electric pneumatic tool “Turbo Wrap”). As a result, it was confirmed that the strand can be pulled out without moving and deforming the transverse strand. Next, the above-mentioned cloth is placed on a shaping mold having a recess having a step of 20 mm, and a plastic having a concave shape of the shaping mold at the five tips of a vibrating body (electric pneumatic tool “turbo lap” manufactured by OHT). When the substrate was pressed against the shaping mold with the jig at a speed of 2 mm / min while attaching the formed shaping jig and vibrating at an amplitude of 0.3 mm and a vibration frequency of 15000 rpm, the substrate was vibrating After moving, deforming, and removing the shaping jig, a carbon fiber cloth preform having the same shape as the beautiful shaping mold without wrinkles and misalignment was obtained.
[0059]
Next, 1 g / m of a urethane-based fixing agent is formed on the preform. ² It was applied and fixed by spraying, and further covered with media for resin flow and bag film and vacuum RTM molded (resin is vinyl ester resin), and a good fiber reinforced composite material free from wrinkles and misalignment was obtained.
[0060]
Comparative Example 1
In the preliminary examination of Example 1, when the weight of the central strand was increased by 10 g, the strand moved 200 mm downward at 200 g. At this time, the lateral strands also moved to cause misalignment.
[0061]
Furthermore, when the carbon fiber cloth was placed on the shaping mold and shaping was carried out in the same manner as in Example 1 except that the frequency was zero, wrinkles and misalignment occurred at the corners. Further, when RTM molding was performed under the same conditions as in Example 1, a fiber-reinforced composite material in which the misalignment portion was not impregnated with resin (no resin was turned) was obtained.
[0062]
Example 2
Three carbon fiber cloths that are the same as in Example 1 are stacked in directions (0 °, 45 °, and 90 ° directions) in which the warp direction forms an angle of 45 degrees with each other, and then on the same shaping mold as in Example 1. Further, the cross end portion was sandwiched between wooden frames, and plastic forming jigs A and B were respectively attached to the same three vibrators and two tips as in Example 1 to perform shaping. . The shaping jig A has a frequency of 250 Hz and an amplitude of 0.4 mm, and the shaping jig B has a frequency of 850 Hz and an amplitude of 1.2 mm. First, the shaping jig A is pressed at a speed of 5 mm / min for 10 seconds. In this case, the separation for 10 seconds was repeated 5 times, and the shaping jig B was shaped in the order of pressing at a speed of 3 mm / min. As a result, all the three strands of the cloth moved while vibrating, and a three-layer preform with no wrinkles or misalignment was obtained (FIG. 6).
[0063]
Example 3
As a preliminary study, plain weave cloth (number of longitudinal strands 8/25 mm, number of transverse strands 8/25 mm, basis weight) obtained by weaving carbon fiber (elastic modulus 235 GPa, strength 3.5 GPa) strands (number of single yarns 3000) 200 g / m ² ) And a fiber reinforced base material to which an epoxy-based fixing agent (glass transition temperature is 70 ° C.) is formed in a rectangular shape so that the warp direction is 1000 mm and the weft direction is 300 mm, as in the preliminary study in Example 1. Cut out and placed on a metal drum having a diameter of 0.9 m and a width of 400 mm, and the four corners were fixed with an adhesive tape. Thereafter, the entire cloth was heated to 80 ° C. with an infrared lamp, and then a 30 g weight was suspended on one central longitudinal strand, and the strand was oscillated (electric pneumatic tool “turbo wrap” manufactured by OHT). ) At 0.2 mm and a frequency of 170 Hz, the transverse strand could be removed without moving or deforming.
[0064]
The carbon fiber cloth is placed on the same shaping mold as in Example 1 and shaped with a shaping jig in the same manner as in Example 1 except that the surface temperature of the cloth is heated to 80 ° C. with an infrared lamp. As a result, a good preform with no misalignment was obtained. In addition, when this preform is shaped, after heating with an infrared lamp is stopped and the temperature is returned to room temperature, it is excellent in form stability that is not misaligned even when handled by hand. ) It turned out to be a preform.
[0065]
Comparative Example 2
In Example 3, except that heating by an infrared lamp was omitted, when shaping was attempted in the same manner as in Example 3, misalignment and bridging (smoothness) occurred in the cloth, and a good preform was obtained. There was no.
[0066]
For confirmation, in the preliminary study of Example 3, an attempt was made to pull out the strand by increasing the weight without heating with an infrared lamp, but it was impossible to pull out the strand in the transverse direction without disturbing it. It was.
[0067]
【The invention's effect】
As described above, according to the preform manufacturing method of the present invention, a three-dimensional shape preform can be formed with simple equipment such as RTM molding without using expensive equipment such as an autoclave. It is possible to manufacture structural members that require high reliability, such as automobiles and automobile parts, and this helps to save energy and improve the environment by reducing the weight of transportation equipment.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of the preform production method of the present invention.
FIG. 2 is a perspective view and a plan view showing an embodiment of the preform manufacturing method of the present invention.
FIG. 3 is a schematic view showing another embodiment of the preform manufacturing method of the present invention.
FIG. 4 is a schematic view showing still another embodiment of the preform manufacturing method of the present invention.
FIG. 5 is an example of a method for quantifying a vibration characteristic condition of a vibrating body according to the present invention.
FIG. 6 is a photograph showing the shape of a preform fiber formed by three-dimensionally shaping the carbon fiber fabric produced in Example 2 of the present invention.
[Explanation of symbols]
1: Shaped mold
2: Reinforced fiber substrate
3: Vibrating body
4: Shaping jig
5: warp
6: Weft
7: Frame
8: Drum
9: Weight

Claims (11)

In the preform manufacturing method of shaping a reinforcing fiber base into the three-dimensional shape using a shaping mold having a three-dimensional shape, the reinforcing fiber base is composed of at least continuous fibers, and the vibration of the vibrating body is The reinforcing fiber base is vibrated by transmitting to the reinforcing fiber base, and at the same time, the reinforcing fiber base is vibrated for a time sufficient for the reinforcing fiber base to be shaped into the three-dimensional shape, thereby A method for producing a preform, wherein the preform is shaped into a shape. The method for manufacturing a preform according to claim 1, wherein the vibrating body is in direct contact with a reinforcing substrate. The preform according to claim 1 or 2, wherein a fixing agent is applied to the reinforcing fiber substrate, and a temperature at which the three-dimensional shape is formed is equal to or higher than a glass transition temperature of the fixing agent. Method. The reinforcing fiber base material is provided with a fixing agent, the reinforcing fibers constituting the reinforcing fiber base material are bonded to each other, and the reinforcing fiber base material is fixed or temporarily fixed. The method for producing a preform according to any one of claims 1 to 3, wherein the amplitude is equal to or greater than an amplitude that cuts the bond between the reinforcing fibers. The plug according to any one of claims 1 to 4, wherein there are a plurality of locations where the reinforcing fiber base is vibrated, and the vibration start time and / or end time is varied at the plurality of locations. Reform manufacturing method. The method for manufacturing a preform according to any one of claims 1 to 5, wherein a part or all of the periphery of the reinforcing fiber base is fixed so as not to move. The method for producing a preform according to any one of claims 1 to 6, wherein there are a plurality of locations where the reinforcing fiber substrate is vibrated, and the amplitude and / or the frequency are varied at the plurality of locations. . The method for manufacturing a preform according to any one of claims 1 to 7, wherein the vibrating body is temporarily and / or completely stopped during manufacturing. The method for manufacturing a preform according to claim 1, wherein the vibration frequency and amplitude of the vibrating body are changed. The method for manufacturing a preform according to any one of claims 1 to 9, wherein a fixing agent is applied during and / or after the manufacturing process of the preform to stabilize the form of the preform. The method for producing a preform according to any one of claims 1 to 10, wherein the reinforcing fiber substrate is made of inorganic fibers.

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