JP2017065066A - Method and device for manufacturing preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine preform with no shaping defects such as wrinkles when manufacturing an FRP molding preform, particularly a preform using a multi-axial stitched base material.SOLUTION: Provided is a method for manufacturing a preform, which includes: a step of acquiring a laminate constituted with an upper face layer on an upper die side formed with at least one piece of reinforced fiber fabric, a lower face layer on a lower die side formed with at least one piece of reinforced fiber fabric, and an intermediate layer formed with at least one piece of multi-axial stitched base material between the upper face layer and the lower face layer; a step of grasping at least a part of peripheral edges of the upper face layer and the lower face layer while giving a tensile force; a step of disposing the laminate, which is grasped at least in a part of the peripheral edges thereof, on a top surface of the lower die having a three-dimensional solid shape; and a step of bringing down the upper die having a press mechanism toward the lower die, and pressing and shaping the laminate.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a preform manufacturing method, and in particular, an FRP capable of forming a sheet-like laminate comprising a reinforcing fiber fabric and a multiaxial stitch base material into a predetermined three-dimensional shape using a pair of upper and lower molds. The present invention relates to a method and apparatus for manufacturing a preform of a molded body.

  For example, in RTM (Resin Transfer Molding) molding, before impregnating a reinforcing fiber substrate with a matrix, it is shaped into a predetermined shape, and the shaped preform is impregnated with a resin. Even when a sheet-like laminate is formed from a reinforcing fiber substrate into a preform having a predetermined relatively complicated shape, it is desired to form the sheet-like laminate without causing defects such as wrinkles.

  In recent years, RTM molding of automotive parts can be produced at a lower manufacturing cost than woven fabrics, and since there is no undulation of reinforced fibers like woven fabrics, it exhibits excellent characteristics. A multiaxial stitch base material in which a plurality of oriented reinforcing fiber sheets are stitched and integrated with stitch yarns is used. Such a multi-axis stitch base material has no undulation like a woven fabric in the reinforcing fiber bundle, so it does not extend at all in the fiber direction and has poor followability to a three-dimensional shape including shapes such as steps and irregularities, such as wrinkles Forming defects are likely to occur. Therefore, there is a need for a process that can be formed without defects using a multiaxial stitch base material.

  Conventionally, various studies have been made to obtain a molded article of fiber reinforced plastic (hereinafter referred to as FRP) having a three-dimensional shape without forming defects. In Patent Document 1, when a sheet-like prepreg containing reinforcing fibers and a matrix resin is pressed between male and female molds, the male and female molds are pressed in the direction from the center of the sheet-shaped prepreg toward the outer edge. On the other hand, a “preform manufacturing method” has been proposed in which a sheet-like prepreg is shaped by pressing with a male-female mold while applying tension in a direction perpendicular thereto. Further, in Patent Document 2, there is an advantage that it is lightweight, does not rust, is easy to mold, has high rigidity, and has a good appearance, so that the thermoplastic resin sheet and the core material are blown apart. A “resin panel molding method” has been proposed. The two thermoplastic resin sheets and the core material are heated and softened at the same time or separately by clamping their peripheral portions, and then separated from the two thermoplastic resin sheets between the two thermoplastic resin sheets. After placing the core material in this state and setting between the pair of molds in this state, the mold is closed and the two thermoplastic resin sheets and the core material are stacked and heat-sealed at the periphery of the mold This is a technique in which a high-pressure gas is supplied between two thermoplastic resin sheets positioned in a cavity of a mold, and the thermoplastic resin sheet is pressed against the inner surface of the cavity and shaped.

JP 2014-51077 A Japanese Patent No. 4278850

  According to “Preform manufacturing method” described in Patent Document 1, since all layers are clamped and pulled, there is a possibility that defective shaping may occur when there is an extreme difference in shaping property in each layer. is there. Further, according to the “resin panel molding method” of Patent Document 2, it has separate clamping mechanisms corresponding to the upper layer on the upper mold side and the lower layer on the lower mold side, but it cannot load external force. Sufficient tension cannot be given to the base material, and the risk of wrinkles is high.

  An object of the present invention relates to a method for manufacturing a preform using a multiaxial stitch base material for an intermediate layer in RTM molding, and a method and apparatus for manufacturing a preform that can be shaped without causing defects such as wrinkles Is to provide.

  In order to achieve the above object, the preform manufacturing method of the present invention comprises an upper layer composed of at least one reinforcing fiber fabric on the upper mold side and at least one reinforcing fiber fabric on the lower mold side. A step of obtaining a laminate composed of a lower surface layer and an intermediate layer composed of at least one multiaxial stitch base material between the upper surface layer and the lower surface layer, at least the peripheral portion of the upper surface layer and the lower surface layer A gripping step of gripping a portion while applying tension, a step of placing the laminate with at least a portion of the peripheral edge gripped on the top surface of a lower mold having a three-dimensional solid shape, and an upper portion having a press mechanism And a step of lowering the mold toward the lower mold and pressing the laminate to form.

  In addition, the preform manufacturing method of the present invention includes an upper layer made of at least one reinforcing fiber fabric on the upper mold side, a lower layer made of at least one reinforcing fiber fabric on the lower mold side, and an upper layer. A step of obtaining a laminate composed of at least one or more multiaxial stitch base material between the lower surface layer and the lower surface layer, and placing the laminate on the top surface of the lower mold having a three-dimensional shape A gripping step of gripping at least a part of the peripheral portion of the upper surface layer and the lower surface layer while applying tension, and lowering an upper die having a press mechanism toward the lower die, and pressing the laminate And the step of shaping.

  In the preform manufacturing method of the present invention, among the peripheral portions of the upper surface layer and the lower surface layer, it is also a preferable aspect to grip a plurality of portions of the peripheral portion independently of each other.

  Here, it is more preferable that a plurality of locations on the peripheral edge are gripped independently of each other and the tension is applied in different directions, or different tensions are applied.

  In particular, at least one multiaxial stitch base material of the intermediate layer is suitable when two or more reinforcing fiber sheets in which a plurality of reinforcing fiber bundles are arranged in parallel are laminated and stitched together with stitch yarns. It is.

  Further, at least one reinforcing fiber fabric constituting the upper surface layer and / or the lower surface layer is preferably one in which reinforcing fibers are oriented in two directions orthogonal to two axes.

  In addition, the preform manufacturing apparatus of the present invention includes a lower mold having a three-dimensional shape and an upper mold having a press mechanism, and an upper layer composed of at least one reinforcing fiber fabric on the upper mold side, and a lower mold side. A laminate composed of at least one lower fiber layer made of a reinforcing fiber fabric and an intermediate layer made of at least one multiaxial stitch base material between the upper surface layer and the lower surface layer along the shape of the lower mold. A preform manufacturing apparatus for manufacturing a preform for an FRP molded body formed by shaping, wherein the clamp grips at least a part of a peripheral edge of the upper surface layer and the lower surface layer while applying tension. A mechanism, a mechanism for arranging the laminated body gripped by the clamp mechanism on the top surface of the lower mold, and a mechanism for lowering the upper mold toward the lower mold and pressing the laminated body. Characterize

  In the preform manufacturing apparatus of the present invention, the clamping mechanism may grip a plurality of peripheral portions independently of each other among the peripheral portions of the upper surface layer and the lower surface layer of the laminate.

  Here, the clamp mechanism grips a plurality of peripheral portions of the upper surface layer and the lower surface layer independently of each other and applies the tension in different directions, or the tension of different magnitudes. Even better.

  According to the preform manufacturing method and manufacturing apparatus of the present invention, the upper mold side upper surface layer and the lower mold side lower surface layer can be gripped by separate clamping mechanisms, and arbitrary tension can be applied to each portion. it can.

  Further, according to the present invention, it is possible to obtain a good shaped body without causing shaping defects such as wrinkles, particularly in the production of a preform using a multiaxial stitch base material for the intermediate layer.

It is a figure which shows typically the manufacturing apparatus of the fiber reinforced plastic molded object preform in one Embodiment of this invention. It is a figure which shows an example of a multi-axis stitch base material. It is a figure which shows the other example of a multiaxial stitch base material. It is a figure which shows the state which lowered | hung the clamp and pressed the laminated body against the type | mold. It is a figure which shows the state which lowered the upper mold | type and pressed the laminated body. It is a figure which shows a clamp mechanism (it can load arbitrary force in all the circumferences). It is a figure which shows the clamp plan 1 (different direction). It is a figure which shows the clamp plan 2 (different magnitude | size). It is a perspective view of the shaping type | mold which concerns on the Example of this invention. It is a figure which shows the laminated body which concerns on the Example of this invention.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram schematically showing an FRP molded body preform manufacturing apparatus 1 according to an embodiment of the present invention. In FIG. 1, a manufacturing apparatus 1 includes a lower die 3 having a three-dimensional solid shape, an upper die 2 having a press mechanism, and an upper surface layer 11 constituting a laminate 14 disposed between the upper die 2 and the lower die 3. Upper surface layer clamps 4a and 4b for holding, and lower surface layer clamps 5a and 5b for holding the lower surface layer 12 are provided. The clamps 4 a, 4 b, 5 a, 5 b are arranged over the entire circumference of the upper surface layer 11 and the lower surface layer 12. The operation of the manufacturing apparatus 1 will be described later. Also. Between the upper surface layer 11 and the lower surface layer 12, two or more reinforcing fiber sheets in which a plurality of reinforcing fiber bundles are arranged in parallel are stacked, and an intermediate including at least one multiaxial stitch base material stitched and integrated with stitch yarns. Layer 13 is disposed. A preform for an FRP molded body can be obtained by press-molding the laminate 14 composed of the upper surface layer 11, the lower surface layer 12, and the intermediate layer 13.

  It is preferable that the size of the laminate 14 before shaping has a sufficient size so that the end of a product (not shown) is shaped without excess or deficiency after shaping. The intermediate layer 13 preferably has a size equal to or smaller than that of the upper surface layer 11 and the lower surface layer 12. In particular, when clamping the peripheral portions of the upper surface layer 11 and the lower surface layer 12, if the upper surface layer 11 and the lower surface layer 12 are slightly larger than the intermediate layer 13, the end portions are easily clamped, and the intermediate layer 13 is easily sandwiched during shaping.

  The reinforcing fiber used in the present invention is not particularly defined, but carbon fiber, glass fiber, aramid fiber, polyparaphenylene benzobis oxazole (PBO) fiber, etc. can be used. A type or a combination of two or more types can also be used. In addition, as the stitch yarn constituting the multiaxial stitch base material, commonly used yarn types can be used, and examples thereof include nylon yarn, polyester yarn, and glass fiber. Using this stitch yarn, a plurality of reinforcing fiber sheets are stitched by reciprocating between the front surface and the back surface through the thickness direction.

  The woven structure of the reinforcing fiber woven fabric constituting the upper surface layer 11 and the lower surface layer 12 is a structure in which continuous fibers are in two directions, and a woven fabric such as plain weave, twill weave, satin weave, and woven weave is preferably used. . Of these, plain weave and twill are preferably used from the viewpoint of mechanical properties, formability, handleability, surface design and the like.

  The form of the reinforcing fiber woven fabric is not particularly limited, but a rectangular shape, particularly a substantially rectangular shape, is a preferable form in that it is easy to apply tension by attaching a clamp described later.

  At least one multiaxial stitch base material used for the intermediate layer 13 is formed by laminating two or more reinforcing fiber sheets in which a plurality of reinforcing fiber bundles are arranged in parallel, and stitched together with stitch yarns. Since a multiaxial stitch base material having a desired strength can be obtained by orienting reinforcing fiber bundles in an arbitrary direction and stitching them in the thickness direction with stitch yarns, the degree of freedom in design is high. Further, the intermediate layer 13 can be formed by simply laminating a predetermined number of multi-axis stitch base materials stitched in advance as a unit.

  As a result, when the preform is shaped on the mold, the laminated body 14 integrated with the intermediate layer 13 sandwiched between the upper surface layer 11 and the lower surface layer 12 is simply set on the mold. Thus, the lamination process is completed. In addition, by using a multiaxial stitch base material, it is possible to save the labor of laminating while changing the orientation angle of each reinforcing fiber bundle one by one, and since it is difficult for the orientation angle to shift, highly reliable molding The product can be obtained at low cost.

  On the other hand, the reinforcing fiber bundle of the multiaxial stitch base material does not have a crimp like that in a woven fabric, so the orientation direction of the reinforcing fiber bundle is poor in following to the mold and is intended to include shapes such as steps and unevenness. If it is shaped as, it may be difficult to shape without any defects.

  FIG. 2 shows an example of a multiaxial stitch base material used in the present invention. For convenience of explanation, the two-layer reinforcing fiber sheets 22a and 22b are illustrated with a slight shift, but are not actually shifted. Reinforcing fiber sheets 22 a and 22 b in which a plurality of reinforcing fiber bundles are arranged in parallel in a sheet shape are stitched in the thickness direction by stitch yarns 23. When the arrow 24 of the multiaxial stitch base material 21 is in the 0 degree direction, the reinforcing fiber bundles 22a and 22b are oriented in the ± 45 degree direction, and the stitch yarn 23 is inserted in the 0 degree direction. Therefore, the multiaxial stitch base material 21 does not extend in the direction of ± 45 degrees, and has a characteristic that it easily extends in the 90 degree direction (direction perpendicular to the arrow 24), and the 0 degree direction in which the stitch yarn is oriented has an intermediate characteristic. It has complex anisotropy. Further, since the reinforcing fiber bundles of the reinforcing fiber sheets 22a and 22b do not have crimps as in the woven fabric, the followability to the mold is poor particularly in the direction of ± 45 degrees, which causes the occurrence of shaping defects such as wrinkles. Become.

  FIG. 3 shows another example of the multiaxial stitch substrate used in the present invention. As in FIG. 2, reinforcing fiber sheets 32 a and 32 b in which a plurality of reinforcing fiber bundles are arranged in parallel in a sheet shape are joined in the thickness direction by stitch yarns 33. In the multiaxial stitch base material 31 of FIG. 3, when the arrow 34 is set to the 0 degree direction, the stitch yarn 33 is oriented in the 0 degree direction and the ± 45 degree direction, which is compared with the multiaxial stitch base material 21 shown in FIG. Thus, the anisotropy in the 0 degree direction and the 90 degree direction is small. Further, the pitch 36 of the stitch yarn 33 is wider than the pitch 26 of the stitch yarn 23 of the multiaxial stitch base material 21 shown in FIG. Therefore, compared with the multiaxial stitch base material 21 shown in FIG. 2, the binding force of the stitch yarn is weak, and the reinforcing fiber bundles 32a and 32b are easy to move with each other, so that they can be flexibly deformed. However, since the deformation resistance in the 90-degree direction is too low, a large necking occurs in the 90-degree direction when pulled in the 0-degree direction, the fiber orientation is disturbed, and the substrate is insufficient for the mold. There is a high possibility that shape defects will occur. Moreover, when it is pulled in the 90 degree direction, it is greatly deformed, and a large gap may be generated between the reinforcing fiber bundles.

The configuration of the multiaxial stitch base material used in the present invention is not limited to the above, and can be arbitrarily selected according to the required specifications. Basis weight is preferably from 100 to 1000 g / ^{m 2} of multiaxial stitch base, 200 to 800 g / ^{m 2} is more preferable. For example, [45 degrees / -45 degrees] and [-45 degrees / -45 degrees], [0 degrees / 45 degrees / -45 degrees] and [0 degrees / -45 degrees / 45 degrees], [0 degrees / 45 degrees / -45 degrees / 90 degrees] and [90 degrees / -45 degrees / 45 degrees / 0 degrees]. In the present invention, since the upper surface layer 11 and the lower surface layer 12 include the reinforcing fiber fabric, it is preferable to orient in a direction different from the fiber orientation of the reinforcing fiber fabric in terms of mechanical properties.

  Similarly to the reinforcing fiber bundle, the orientation angle and pitch of the stitch yarn, the tension at the time of stitching, and the like are not particularly limited, and can be arbitrarily selected and inserted according to the required specifications. In addition, the orientation angle and pitch of the stitch yarns 23 and 33, the tension applied at the time of stitching, and the like are factors that influence the shapeability of the multiaxial stitch base material, and can be designed according to the target shape. It is preferable that the deformation resistance at the time of shaping does not become too small without impairing the handleability of the base material, and the pitch is wide, and it is preferable to reduce the tension at the time of sewing in terms of improving the shapeability. . With respect to the orientation angle, it is preferable in terms of mechanical strength that the reinforcing fiber bundle is inserted in a direction in which it is not oriented. However, as described above, the followability to the mold is poor as compared with the reinforced fiber fabric, and poor shaping tends to occur.

  FIG. 4 shows a state in which the laminate 14 composed of the upper surface layer 11, the lower surface layer 12, and the intermediate layer 13 is pressed against the mold by lowering the upper surface layer side clamps 4a and 4b and the lower surface layer side clamps 5a and 5b. ing. Further, the upper surface layer 11 and the lower surface layer 12 are in contact with the intermediate layer 13, and tensions 7a and 7b are applied to the upper surface layer side, and tensions 8a and 8b are applied to the lower surface layer side, respectively. By applying tension to the upper surface layer 11 and the lower surface layer 12, respectively, wrinkle generation due to out-of-plane deformation during shaping of the reinforcing fiber fabric constituting the upper surface layer 11 and the lower surface layer 12 is suppressed. Further, the intermediate layer 13 made of a multiaxial stitch base is not good in formability as compared with the upper surface layer 11 and the lower surface layer 12 made of reinforcing fiber fabric, but deforms following the upper surface layer 11 and the lower surface layer 12. Therefore, the intermediate layer 13 can be shaped while suppressing wrinkles due to out-of-plane deformation.

  Further, the deformation resistance is low as in the 90-degree direction of the multiaxial stitch base material 30 shown in FIG. 3. It is suppressed by friction due to contact pressure from the layer 11 and the lower surface layer 12. As described above, between the upper surface layer 11 and the lower surface layer 12 made of a reinforcing fiber fabric excellent in formability, the base material has a high degree of design freedom and is manufactured in advance as a single base material. By shaping with an intermediate layer made of a material, a highly reliable preform having excellent mechanical properties can be produced efficiently and at low cost.

  Next, the operation of the manufacturing apparatus 1 shown in FIG. 1 will be described. In FIG. 1, the upper surface layer 11 made of a reinforced fiber fabric is gripped by the upper surface layer clamps 4a and 4b, the peripheral portion of the lower surface layer 12 is gripped by the lower surface layer clamps 5a and 5b, and tensions 7a and 7b are applied to the upper surface layer side. The shape is formed while applying tensions 8a and 8b to the lower surface layer side. Although not shown, the upper surface layer clamps 4a and 4b and the lower surface layer clamps 5a and 5b are provided over the entire circumference of the reinforcing fiber fabric, and are also held by clamps not shown. At this time, the intermediate layer 13 disposed between the upper surface layer 11 and the lower surface layer 12 is simply sandwiched between the upper surface layer 11 and the lower surface layer 12, and the peripheral portion of the intermediate layer 11 is the upper surface layer 11. It is not gripped like the peripheral edge of the lower surface layer 12 or the peripheral edge of the lower surface layer 12. With this configuration, only the peripheral edge portion of the upper surface layer 11 and the peripheral edge portion of the lower surface layer 12 are held by the clamp, and tension is applied to the upper surface layer 11 and the lower surface layer 12.

  As a timing for performing the clamping, it is possible to clamp the peripheral portions of the upper surface layer 11 and the lower surface layer 12 with the clamp after the laminated body 14 is arranged on the top surface of the lower mold 3, or the upper surface layer of the laminated body 14 in advance. 11 and the lower surface layer 12 can also be arranged on the top surface of the lower mold 3 while holding the peripheral portions of the lower mold 12 with clamps.

  FIG. 5 shows a state in which the upper mold 2 is lowered and the laminate 14 is pressed. When the peripheral portions of the upper surface layer 11 and the lower surface layer 12 are gripped by the clamp and the clamp is lowered, the laminate 14 is pressed against the lower mold and integrated. At this time, the intermediate layer 13 is subjected to contact pressure due to being sandwiched during shaping by applying tension to the upper surface layer 11 and the lower surface layer 12, deforming following the upper surface layer 11 and the lower surface layer 12, and applying pressure. Will be shaped. Further, when the upper die 2 is lowered and pressed, the laminated body 14 is shaped along the three-dimensional shape of the lower die, and becomes a preform of the FRP plastic molding.

  Further, the clamping range of the upper surface layer and the lower surface layer and the magnitude, range, and direction of the load tension are not particularly limited, and are given in an arbitrary size, direction, and range in consideration of the type and shape of the substrate. It is possible. In this way, each clamp can grip a plurality of locations on the peripheral portions of the upper surface layer and the lower surface layer independently of each other.

  FIG. 6, FIG. 7, and FIG. 8 are other embodiments of the present invention, and only the laminated body 14 clamped before shaping is schematically shown as a bird's eye view. In FIG. 6, the upper surface layer clamp 41 at the peripheral edge of the upper surface layer 11 and the lower surface layer clamp 42 at the peripheral edge of the lower surface layer 12 extend over the entire circumference, and can be configured so that tension can be applied in any size and direction. Has been. Further, it is not necessary to clamp the entire side, and it is possible to clamp only a part of one side and apply tension. FIG. 7 shows an example in which the clamping range is different between the peripheral edge of the upper surface layer 11 and the peripheral edge of the lower surface layer 12, and tension is applied in different directions. FIG. 8 shows an example in which tension is applied to the upper and lower layers 11 and the peripheral portion of the lower surface layer 12 is the same in the clamping range and the direction in which the load is applied. .

  Thus, the manufacturing apparatus 1 is configured so that the clamping range and the magnitude and direction of the load tension can be arbitrarily selected depending on the type of reinforcing fiber fabric used for the upper and lower surface layers and the shape to be shaped. .

Example 1
FIG. 9 shows a mold to be shaped. A mold 102 (1000 mm × 700 mm, height 20 mm) to be shaped is placed on the base surface 101 (1200 mm × 900 mm). Although not shown, there is an upper die corresponding to the shaping target shape, and press shaping can be performed in a state where the base material is disposed on the top surface of the die 102. FIG. 10 shows the laminate 204 used in the example. Each of the upper surface layer 201 and the lower surface layer 202 is composed of a single reinforcing fiber fabric (woven structure: plain weave, fabric weight: 198 g / m ² , reinforcing fiber: T300), and the multiaxial stitch base material of the intermediate layer 203 is (fiber orientation) : 45 ° / −45 °, stitch yarn: polyester yarn, 5 mm pitch, chain stitch (0 ° direction single ring stitching), basis weight: 360 g / m ² , reinforcing fiber: T700), and 3 sheets. The base material size is 1150 mm x 800 mm for the upper and lower surface layers, the intermediate layer is 1100 mm x 800 mm, clamps the 25 mm range from both ends in the longitudinal direction of the upper and lower surface layers, loads 1.0 KN each, sandwiches the intermediate layer, The mold was lowered and shaped. As a result, there was no generation of wrinkles, and a good preform without disturbance of fiber orientation due to the constriction of the intermediate layer in the 90-degree direction and lack of substrate could be obtained.

(Comparative Example 1)
The upper and lower surface layers were shaped without applying a tension under the same conditions as in Example 1. As a result, waviness of the base material occurred at the end of the intermediate layer 13 in the width direction. Moreover, although the base material was constricted in the direction of 90 degrees and the base material was not insufficient with respect to the mold, the fiber orientation was disturbed.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for manufacturing fiber reinforced plastic molded body preforms such as automobile bonnets, roofs, door panels, tailgates, trunk lids, trunk boards, rear package trays and the like.

DESCRIPTION OF SYMBOLS 1 Preform manufacturing apparatus 2 Upper mold | type 3 Lower mold | type 4a, 4b Upper surface layer clamp 5a, 5b Lower surface layer clamp 7a, 7b, 8a, 8b Tensile force 11 Upper surface layer
12 Lower surface layer 13 Intermediate layer 14 Laminate 21 Multiaxial stitch base material 22a, 22b Reinforcing fiber sheet 23 Stitch yarn 24 Multiaxial stitch base material 0 degree direction 25 Stitch yarn pitch

Claims (12)

At least one or more upper layer composed of at least one reinforcing fiber fabric on the upper mold side, a lower layer composed of at least one reinforcing fiber fabric on the lower mold side, and at least one between the upper layer and the lower layer A step of obtaining a laminate composed of an intermediate layer composed of a multiaxial stitch base material,
A gripping step of gripping at least a part of a peripheral edge of the upper surface layer and the lower surface layer while applying tension;
A step of arranging the laminate in which at least a part of the peripheral edge is held on the top surface of the lower mold having a three-dimensional solid shape;
Lowering the upper mold having a press mechanism toward the lower mold, and pressing the laminate to shape the mold;
A process for producing a preform, comprising: At least one or more upper layer composed of at least one reinforcing fiber fabric on the upper mold side, a lower layer composed of at least one reinforcing fiber fabric on the lower mold side, and at least one between the upper layer and the lower layer A step of obtaining a laminate composed of an intermediate layer composed of a multiaxial stitch base material,
Placing the laminate on the top of the lower mold having a three-dimensional solid shape;
A gripping step of gripping at least a part of a peripheral edge of the upper surface layer and the lower surface layer while applying tension;
Lowering the upper mold having a press mechanism toward the lower mold, and pressing the laminate to shape the mold;
A process for producing a preform, comprising:   The preform manufacturing method according to claim 1, wherein among the peripheral portions of the upper surface layer and the lower surface layer, a plurality of portions of the peripheral portion are gripped independently of each other.   The preform manufacturing method according to claim 3, wherein a plurality of locations on the peripheral edge are gripped independently of each other, and the tension is applied in different directions.   The method for manufacturing a preform according to claim 3, wherein a plurality of locations on the peripheral edge are gripped independently of each other and different tensions are applied.   The at least one multiaxial stitch base material of the intermediate layer is obtained by laminating two or more reinforcing fiber sheets in which a plurality of reinforcing fiber bundles are arranged in parallel and stitching and integrating them with stitch yarns. The method for producing a preform according to any one of the above.   The preform according to any one of claims 1 to 5, wherein at least one reinforcing fiber woven fabric constituting the upper surface layer and / or the lower surface layer has reinforcing fibers oriented in two directions orthogonal to two axes. Production method.   The method for manufacturing a preform according to any one of claims 1 to 7, wherein the reinforcing fiber woven fabric is substantially rectangular and grips a pair of opposing peripheral edges. By a lower mold having a three-dimensional solid shape and an upper mold having a press mechanism, an upper layer composed of at least one reinforcing fiber fabric on the upper mold side and a lower surface composed of at least one reinforcing fiber fabric on the lower mold side. A preform for an FRP molded body formed by forming a laminate composed of a layer and an intermediate layer composed of at least one multiaxial stitch base material between the upper surface layer and the lower surface layer along the shape of the lower mold A preform manufacturing apparatus for manufacturing a preform,
A clamping mechanism for gripping at least a part of the peripheral edge of the upper surface layer and the lower surface layer while applying tension;
A mechanism for placing the laminate gripped by the clamp mechanism on the top surface of the lower mold;
A mechanism for lowering the upper mold toward the lower mold and pressing the laminate;
An apparatus for manufacturing a preform.   10. The preform manufacturing apparatus according to claim 9, wherein the clamp mechanism grips a plurality of peripheral portions of the upper surface layer and the lower surface layer independently of each other. 11.   11. The preform manufacturing apparatus according to claim 10, wherein the clamping mechanism grips a plurality of peripheral portions of the upper surface layer and the lower surface layer independently of each other and applies the tension in different directions.   11. The preform manufacturing apparatus according to claim 10, wherein the clamping mechanism grips a plurality of peripheral portions of the upper surface layer and the lower surface layer independently of each other, and applies the different tensions. 11. .