JP2012192542A - Rtm molding device and molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an RTM molding device that can achieve a high resin-impregnation velocity keeping the number of injection holes small when the resin is injected from a plurality points of the inner surface of a reinforcing fiber base material to achieve a short impregnation time, and to provide a molding method.SOLUTION: There are provided: the RTM molding device, wherein a mold forming a cavity where the reinforcing fiber base material 7 is arranged includes a resin casting opening 9 open to face one surface of the reinforcing fiber base material 7, and wherein the resin is cast from the resin casting opening 9 to impregnate the reinforcing fiber base material with the resin, a cross-sectional surface of a resin passage at the tip end 21 of the resin casting opening 9 is enlarged, in view of the resin flow direction, compared with the cross-sectional surface of the resin passage just in front of the tip end; and the RTM molding method.

Description

  The present invention relates to an RTM molding apparatus and a molding method, and in particular, an RTM molding apparatus and a molding capable of significantly increasing the resin impregnation speed without increasing the size of the equipment when the resin is injected from the surface of the reinforcing fiber base. Regarding the method.

  A reinforcing fiber base (or a preform made of a reinforcing fiber base) is placed in the cavity of the mold, and the resin is injected from a resin inlet arranged facing the one side of the reinforcing fiber base to strengthen it. RTM molding methods for impregnating fiber base materials are known, and in particular, RTM molding in which a plurality of resin injection ports are provided and a resin is injected from a plurality of injection points to shorten the resin injection / impregnation time. A method is known (for example, Patent Document 1), and such an injection method is also called an RTM multipoint injection method.

  In such an RTM multipoint injection method, in order to increase productivity in in-plane resin injection to the reinforcing fiber base, the resin injection valve mechanism is used to mechanically switch between resin injection / stop. Since it can be performed and the replacement of the resin injection tube is not necessary, it is possible to achieve automation in addition to shortening the impregnation time. Moreover, the impregnation time can be shortened by providing a plurality of resin injection ports. Furthermore, when the diameter of the resin injection port is increased, the impregnation rate becomes faster.

JP 2010-89501 A

However, the following problems remain in the RTM multipoint injection method as described above.
(1) In resin injection from the surface of the reinforcing fiber base, if the number of injection ports is increased, the impregnation will be faster, but if too many are provided, the injection mechanism will increase too much, resulting in an increase in equipment costs and installation space. It becomes more and more difficult to arrange many injection mechanisms in a limited space of the mold.
(2) If the diameter of the injection port of the resin injection mechanism is simply increased, the device itself may be enlarged and mounting may be difficult, and the resin may be cured and fixed in the opening / closing mechanism of the injection port. A certain area becomes large, and troubles that hinder opening and closing are likely to occur.

  Therefore, the object of the present invention is to pay attention to the above-mentioned problems, and to make it possible to shorten the impregnation time by injecting resin from multiple points within the surface of the reinforcing fiber base. Provided are an RTM molding apparatus and a molding method capable of reducing the number to solve the problems related to the equipment cost and the installation space for the injection mechanism and realizing a high resin impregnation speed while keeping the number of resin injection ports small. There is.

  In order to solve the above-described problems, an RTM molding apparatus according to the present invention includes a resin injection port that opens to face one surface of the reinforcing fiber base in a mold that forms a cavity in which the reinforcing fiber base is disposed. In an RTM molding apparatus that is provided, injecting resin from the resin injection port and impregnating and curing the reinforcing fiber base material, the cross section of the resin flow path at the front end portion of the resin injection port is viewed from the resin flow direction. It consists of what was expanded with respect to the cross section of the resin flow path in front of a part. The structure of the RTM molding apparatus according to the present invention is particularly suitable when a plurality of resin injection ports are provided, but the present invention is established even when the number of resin injection ports is singular. .

  In such an RTM molding apparatus according to the present invention, the cross section of the resin flow path at the tip of the resin injection port is enlarged relative to the cross section of the resin flow path up to that point. In other words, only the portion of the resin inlet that reaches one surface of the reinforcing fiber base (that is, only the portion that reaches one surface of the product to be molded) has a large cross section of the resin flow path. Therefore, it becomes the same form that the apparent diameter of the injection port for injecting the resin into the cavity is increased, and if one resin injection port is seen, the resin injection speed is increased, and accordingly, to the base material. The resin impregnation rate is increased. As a result of increasing the resin injection / impregnation rate, when multiple resin injection ports are provided, it is possible to obtain an impregnation rate equal to or higher than that of the conventional structure even if the number of resin injection ports is reduced. Can be shortened. Furthermore, since the cross section of the resin flow path at the front end of the resin inlet directly facing the reinforcing fiber base of the resin inlet is enlarged, the portion corresponding to the resin impregnation start surface on the surface of the reinforcing fiber base A large area can be secured, and from this point, the impregnation rate can be increased, and it can contribute to the suppression of uneven resin impregnation on the surface of the molded product to be molded, thereby improving the surface quality of the molded product. Is also possible.

  As an enlarged form of the cross section of the resin flow path at the front end of the resin inlet, the cross section of the resin flow path immediately before the front end is in a trumpet shape and / or a step shape (that is, simply on the downstream side of the flow path). In this case, it is possible to adopt a configuration in which the shape is widened toward a trumpet shape, a shape in which the diameter is expanded in a stepped shape, a shape in which these are combined, and the like.

  Further, the inner surface of the molding die from the position corresponding to the position of the resin flow channel immediately before the front end of the front end of the resin injection port having the resin flow channel having an enlarged cross section. It is also possible to adopt a form that is formed in a shape extending in at least one direction (preferably in a shape extending on both sides or in a plurality of directions). In this case, as shown in each embodiment described later, the opening of the tip portion on the inner surface of the mold has a width direction dimension corresponding to the diameter of the resin flow channel immediately before the tip portion, and the width direction dimension. It is preferably formed in a shape having a large lengthwise dimension and extending in a strip shape. In other words, the shape of the opening of the tip portion, that is, the shape of the portion that reaches the product surface of the resin injection port can be made, for example, the same shape as a runner dug into a mold. The same effect as when the number of entrances is increased can be obtained. By adopting such an expanded form of the resin flow path cross section at the tip of the resin inlet, it is possible to start resin impregnation from a more appropriate site over a wider range and further to continue the impregnation for the reinforcing fiber base. Thus, more uniform resin impregnation is possible over the entire region of the reinforcing fiber base material, which can contribute to improving the quality of the molded product.

  In the RTM molding device according to the present invention, the resin injection valve mechanism as described above can be employed. For example, a structure in which a valve body that opens and closes the resin injection port by being advanced and retracted along the direction toward the distal end of the resin injection port can be employed. When such a structure is adopted, the stop position of the tip of the valve body when the resin inlet is closed reaches the position where the cross-section of the resin flow path at the tip of the resin inlet reaches the expansion start position. It is preferable that it is set. That is, for the resin flow path up to the expansion start position of the cross section, the diameter of the resin flow path and the diameter of the valve body are easily set to substantially the same diameter so that the valve can be opened and closed for opening and closing the resin inlet. When the body is advanced or retracted (especially when it is retracted), it is possible to prevent the occurrence of a problem that the valve body pulls in the adhered resin and the resin adheres to hinder the opening and closing operation of the valve body. If the tip moves beyond the cross-section enlargement start position and into the tip of the resin inlet whose cross-section is enlarged, the resin will inevitably adhere to the outer peripheral surface of the valve body in the tip. Therefore, there is a risk that the opening / closing operation may be hindered due to adhesion of the adhered resin. Therefore, in the above structure, in particular, such a fear is eliminated by stopping the stop position of the tip of the valve body until the expansion start position of the cross section of the resin flow path.

  In the RTM molding method according to the present invention, a reinforcing fiber base is disposed in a cavity formed in a molding die, and a resin is injected from a resin inlet that is opened to face one surface of the reinforcing fiber base. In the RTM molding method in which the reinforcing fiber base material is impregnated and cured, the resin flow path at the tip portion of the resin injection port has a cross section that is in the resin flow direction with respect to the cross section of the resin flow channel immediately before the tip portion. The method is characterized in that the resin is injected toward the reinforcing fiber substrate through the tip of the resin injection port that is formed so as to expand and the cross section is expanded.

  In such an RTM molding method, as described in the above-mentioned section of the RTM molding apparatus, a high impregnation rate can be achieved while keeping the number of resin injection ports small, and the impregnation time is shortened. It becomes possible.

  In the RTM molding method, when a valve body that opens and closes the resin injection port by being advanced and retracted along the direction toward the tip of the resin injection port is provided, as described above, when the resin injection port is closed. It is preferable that the stop position of the tip of the valve body is set to a position from the resin inlet to the expansion start position of the cross section of the resin flow path at the tip of the resin inlet. After the resin is injected and impregnated into the reinforcing fiber base material and cured, the resin injection in which the cross section is enlarged on the resin-impregnated reinforcing fiber base material in the direction from the stop position at the tip of the valve body toward the reinforcing fiber base material is performed. The part which consists only of cured resin remains in the three-dimensional shape corresponding to the front-end | tip part of an inlet_port | entrance. However, the part consisting only of this cured resin may be left as it is if there is no problem in design and function. If there is a problem, it can be removed by cutting or the like in a post-processing step such as peripheral trimming. Good.

  Thus, according to the RTM molding apparatus and molding method according to the present invention, when injecting resin from within the surface of the reinforcing fiber base, particularly when injecting multiple points, the cross section of the resin flow path of the resin injection port is obtained. By enlarging only at the tip, it is possible to reduce the number of resin injection ports, and keep the number of resin injection ports to a small number without causing an increase in equipment costs or a problem of installation space for the injection mechanism. It is possible to achieve a sufficiently high resin impregnation rate while remaining. By increasing the impregnation speed, the impregnation time can be shortened, and the molding cycle time can be shortened to improve the productivity. In addition, the opening area of the tip of the resin inlet that directly faces the reinforcing fiber substrate can be expanded, and the resin impregnation performance to the substrate can be improved to improve the surface quality of the molded product and the quality of the molded product. It is also possible to measure.

It is a schematic longitudinal cross-sectional view of the RTM shaping | molding apparatus which concerns on one embodiment of this invention. It is an expansion schematic longitudinal cross-sectional view of the resin injection inlet front-end | tip part in the apparatus of FIG. It is a schematic longitudinal cross-sectional view of the resin inlet front-end | tip part which concerns on another embodiment different from FIG. It is a schematic plan view of the molding die inner surface for demonstrating the example of a shape of the resin injection hole front-end | tip part which concerns on another embodiment. It is the schematic longitudinal cross-sectional view (FIG. 5 (A)) in alignment with the AA of FIG.4 (B), and the schematic longitudinal cross-sectional view (FIG.5 (B)) in alignment with BB. FIG. 5 is a schematic plan view of the inner surface of a mold for explaining an example of the shape of a resin inlet tip according to an embodiment different from FIG. It is a schematic longitudinal cross-sectional view for demonstrating the problem when the resin injection inlet front-end | tip part is expanded too much. FIG. 7 is a schematic plan view of the inner surface of a mold showing an example of a conventional multi-point injection structure for comparison with FIG. 6. It is a schematic longitudinal cross-sectional view of the conventional resin injection port.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an RTM molding apparatus according to an embodiment of the present invention. In FIG. 1, the RTM molding apparatus 1 includes an upper mold 4 and a lower mold 5 as a mold 3 for forming a cavity 2. The upper mold 4 is clamped and opened by a press mechanism 6. It has become. In the cavity 2, a reinforcing fiber base 7 is made of a laminated body of reinforcing fiber bases, for example, and a preform shaped in advance in a predetermined shape is disposed. In a state where the reinforcing fiber base 7 is disposed in the cavity 2, the upper mold 4 is clamped to the lower mold 5, and a resin for constituting the FRP is supplied from the resin supply path 8. Resin is injected into the cavity 2 from a plurality of resin injection ports 9 that open to face one surface (upper surface) of the resin 7 and impregnated in the reinforcing fiber base 7. The resin injection port 9 is opened and closed by, for example, a pin-shaped valve body 10, and the periphery of the cavity 2 is sealed with a sealing material 12. The molding die 3 is heated and cooled by, for example, a heat medium flowing through the heat medium flow passage 11, and is heated during resin injection so that the resin is satisfactorily impregnated. After the resin impregnation, cooling (natural cooling is also possible). The injected and impregnated resin is cured to produce a predetermined FRP molded product.

  In the RTM molding apparatus 1 as described above, the cross section of the resin flow path at the distal end portion 21 (the distal end portion facing the reinforcing fiber base 7) of the resin injection port 9 is, for example, as shown in FIG. As viewed in the flow direction, the cross section of the resin flow path immediately before the tip 21 is enlarged. In the example shown in FIG. 2A, the distal end portion 21 is expanded in a trumpet shape with respect to the shape of the resin injection port 9 so far. By enlarging the cross section of the resin flow path at the distal end portion 21 of the resin injection port 9, a sufficiently high resin injection / impregnation speed is ensured even if the number of the resin injection ports 9 is small. Therefore, the molding cycle time is shortened and the productivity is improved while suppressing the equipment cost.

  The resin injection port 9 is opened and closed by the valve body 10, and the stop position when the resin injection port 9 of the tip 10a of the valve body 10 is closed is as shown in FIG. Is set up to a position that reaches the expansion start position of the cross section of the resin flow path at the distal end portion 21. In the illustrated example, the position is just set to the expansion start position. With such a configuration, the state in which the resin adheres to the outer periphery of the distal end portion of the valve body 10, and the trouble that the adhered resin adheres and hinders the valve operation are avoided, and stable molding is ensured. In addition, as described above, in the direction from the stop position of the tip of the valve body 10 toward the reinforcing fiber base 7, the portion made of only the cured resin in a three-dimensional shape corresponding to the tip 21 on the resin-impregnated reinforcing fiber base However, if there is no problem in terms of design and functionality, the part consisting only of the cured resin may be left as it is. What is necessary is just to remove by cutting etc.

  The enlarged form of the cross section of the resin flow path at the distal end portion of the resin injection port 9 is not limited to the form shown in FIG. 2. For example, as shown in FIG. 3, the distal end portion 31 of the resin injection port 9 is stepped. Or may be enlarged in a trumpet shape after being enlarged in a step shape. However, if the degree of expansion of the cross section of the resin flow path at the front end is too large, for example, when the cross section of the resin flow path is excessively enlarged as shown in FIG. The press holding area with respect to the base material surface is insufficient, and there is a possibility that the reinforcing fiber base material 7 partially enters the space in the tip portion 41 and the base material 7 is swelled. Therefore, it is preferable to suppress the degree of expansion of the cross section of the resin flow path at the tip within a range where such undulation does not occur.

  In addition, as a shape of the opening in the inner surface of the mold (e.g., the upper mold) of the tip of the resin inlet having the resin flow path having an enlarged cross section as described above, a runner dug into the mold It can also be made into the shape extended in equivalent strip | belt shape. For example, as shown in FIG. 4B, the upper mold 51 is provided with a plurality of (four in the illustrated example) resin injection ports 52 as shown in FIG. The mold 61 is provided with a smaller number of resin injection ports 62 (two in the illustrated example), and the inner surface of the upper mold 61 of the tip 63 having a resin flow path with an enlarged transverse section of each resin injection port 62. The opening shape in FIG. 5 is at least one direction along the inner surface of the molding die from the position corresponding to the position of the resin flow path immediately before the tip portion 63 (that is, the position of the resin injection port 62 so far). ) It can be formed in a shape extending in a strip shape. In the form shown in FIG. 4B, the cross-sectional shape of the distal end portion 63 viewed along the line AA in FIG. 4B is as shown in FIG. 5A, and FIG. The cross-sectional shape of the tip portion 63 viewed along the line BB is as shown in FIG. In such an opening shape of the tip portion, it has a width equivalent to the diameter of the resin injection port 62 immediately before the tip portion 63, and only the longitudinal dimension of the opening of the tip portion 63 viewed along the line AA. Therefore, the swell as shown in FIG. 7 is prevented and the resin injection / impregnation rate is increased. Further, by appropriately extending the opening of the tip portion 63, the surface of the reinforcing fiber base 7 can be injected and impregnated with resin from a wider range. It can also contribute to improvement.

  The opening shape on the inner surface of the molding die at the front end of the resin inlet that extends in a strip shape as described above can be appropriately bent or extended in the direction toward the corner of the molding die (or base material). It is. For example, as shown in FIG. 6, the resin spreads over the resin inlet 72 provided in the upper mold 71, and the opening shape on the inner surface of the upper mold 71 of the tip 73 having a resin flow path whose cross section is enlarged. It can be set as the shape extended toward the corner of the shaping | molding die considered difficult. In this way, by forming the opening shape of the tip 73 into an appropriate shape according to the shape of the mold or the molded product, more desirable resin injection / impregnation can be performed to every corner.

  In addition, in order to compare with the various embodiments of the present invention as described above, examples of conventional structures are shown in FIGS. As shown in FIG. 8, in the prior art, in order to increase the resin injection / impregnation speed, it was necessary to provide a large number of resin injection ports 101 in the mold 102. There was a problem with the installation space of the opening and closing mechanism. Further, as shown in FIG. 9 (A), each resin injection port 101 is not formed with an enlarged tip as in the present invention, so that the resin injection / impregnation rate for each resin injection port 101 can be increased. It is difficult to reduce the number of resin injection ports 101. However, as shown in FIG. 9 (B), the tip of the valve body 103 may be advanced to the surface of the reinforcing fiber base 104, so that only a portion of the cured resin remains after the resin is cured.

  The RTM molding apparatus and molding method according to the present invention are particularly suitable for molding a relatively large molded product in a short cycle time without increasing the size of the equipment.

DESCRIPTION OF SYMBOLS 1 RTM molding apparatus 2 Cavity 3 Mold | die 4,61,71 Upper mold | type 5 Lower mold | type 6 Press mechanism 7 Reinforcement fiber base material 8 Resin supply path 9, 6272, Resin inlet 10 Valve body 10a Tip of valve body 11 Heat medium distribution Path 12 Sealing material 21, 31, 63, 73 The tip of the resin inlet

Claims (8)

  The mold for forming the cavity in which the reinforcing fiber base is disposed is provided with a resin injection port that opens to face one surface of the reinforcing fiber base, and the resin is injected from the resin injection port to thereby form the reinforcing fiber base. In the RTM molding apparatus for impregnating and curing the resin, the cross section of the resin flow path at the front end of the resin injection port is enlarged with respect to the cross section of the resin flow path immediately before the front end when viewed in the resin flow direction. RTM molding equipment.   The RTM molding apparatus according to claim 1, wherein a plurality of the resin injection ports are provided.   The cross section of the resin flow path in the front-end | tip part of the said resin inlet is expanded in the trumpet shape or / and the step shape with respect to the cross-section of the resin flow path in front of the said front-end | tip part. RTM molding equipment.   An inner surface of the molding die from a position corresponding to the position of the resin flow channel immediately before the tip of the inner surface of the molding die of the tip of the resin injection port having a resin channel having an enlarged transverse section The RTM molding device according to claim 1, wherein the RTM molding device is formed in a shape extending along at least one direction.   A shape in which the opening of the tip on the inner surface of the mold has a widthwise dimension corresponding to the diameter of the resin flow channel immediately before the tip and a lengthwise dimension larger than the widthwise dimension. The RTM molding device according to claim 4, wherein   A valve body that opens and closes the resin injection port by moving forward and backward along the direction toward the distal end of the resin injection port is provided, and the stop position of the distal end of the valve body when the resin injection port is closed, The RTM molding device according to any one of claims 1 to 5, wherein the RTM molding device is set to a position up to an expansion start position of a cross section of a resin flow path at a tip portion of the resin injection port.   A reinforcing fiber base is disposed in a cavity formed in a mold, and a resin is injected from a resin injection port that is opened to face one side of the reinforcing fiber base, and the reinforcing fiber base is impregnated and cured. In the RTM molding method, the resin flow path at the tip of the resin inlet is formed such that the cross section thereof is larger than the cross section of the resin flow path immediately before the tip when viewed in the resin flow direction. An RTM molding method comprising injecting a resin toward the reinforcing fiber base through a tip of a resin injection port having an enlarged surface.   A valve body that opens and closes the resin injection port by moving forward and backward along the direction toward the distal end of the resin injection port is provided, and the stop position of the distal end of the valve body when the resin injection port is closed, It is set to a position up to the expansion start position of the cross section of the resin flow path at the tip of the resin injection port, resin is injected from the resin injection port, and the reinforcing fiber base material is impregnated and cured. After that, in the direction from the stop position of the tip of the valve body toward the reinforcing fiber substrate, the resin impregnated reinforcing fiber substrate remains on the resin-impregnated reinforcing fiber substrate in a three-dimensional shape corresponding to the distal end portion of the resin injection port whose cross section is enlarged. The RTM molding method according to claim 7, wherein a portion consisting only of the cured resin is removed.

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