JPH07178820A - Production of composite structure - Google Patents

Abstract

PURPOSE:To mold a product in which dislocation of the grain of fiber and a dent are not generated on the surface of the product, dimensional precision of an assembled article is improved and a wrinkle and rupture of fiber are not generated. CONSTITUTION:A method for producing a composite structure is constituted of a process for molding the laminated reinforced fibrous fabrics into a plurality of fabric members by a split forming mold, a process for impregnating the fabric members with a shape retention material in a state for holding the fabric members in the forming mold and hardening them, a process for taking out the fabric members from the forming mold and cutting the exess part, a process for sewing the fabric members together which have been cut in a prescribed dimension, a process for fitting the fabric members sewed in a prescribed product shape to a mold for impregnating the fabric members with resin, removing the shape retention material and drying the fabric members and a process for filling resin into the mold and hardening it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite material structure for manufacturing a three-dimensional structure from a composite material such as fiber reinforced plastic.

[0002]

2. Description of the Related Art When a three-dimensional structure is manufactured from a composite material such as fiber-reinforced plastic, a three-dimensional weaving machine can form a preform having an ideal shape with no fibers. Requires special equipment according to the shape of the product, so that it is difficult to apply it in a small-scale production because the manufacturing cost is huge.

The three-dimensional structure is appropriately divided according to the shape, molded as a part with a composite prepreg, and then the parts are combined and sewn together and cured to form a three-dimensional structure having a desired strength and shape. The molding method is described, for example, in JP-A-1-257691.

A method for manufacturing a composite material in which a thermosetting composite material before complete curing or a thermoplastic composite material after inter-layer bonding is sewn with fibers while applying ultrasonic waves to a needle tip is disclosed in, for example, Japanese Patent Application Laid-Open Publication No. It is described in JP-A-3-286841.

A method of manufacturing a composite material is also known, in which a needle or a prepreg is preheated before each component is sewn.

[0006]

The molding method for forming a three-dimensional structure by suturing divided parts is such that the sewing machine does not move smoothly due to the resin adhering to the needle during suturing, There is a problem that the weave of the fiber and the dent occur.

Further, in the method of manufacturing a composite material in which ultrasonic waves are applied to the needle tip to suture, resin does not adhere to the needle during suturing, but a special device is used to apply ultrasonic wave to the needle tip. There is a problem of needing it.

Further, the method for manufacturing a composite material in which needles and prepregs are preheated also requires a special heating device, and since the prepreg resin has adhesiveness, it is difficult to handle and the parts are flexible. There is a problem that deformation is likely to occur during handling.

The present invention has been made in view of the above points, and without using a special device, there is no deviation or dent of the weave of the fiber on the surface of the product, and stitching is performed while maintaining a shape without deformation. At the same time, it is an object of the present invention to provide a method for manufacturing a composite material structure that enables molding in a state that is easy to handle.

[0010]

According to a method for manufacturing a composite material structure of the present invention, a plurality of woven fabric members are molded by a molding die in which a reinforcing fiber woven fabric laminated according to the thickness of a product is divided according to the shape. A step of impregnating a shape-retaining material in a state where the fabric member is held in a mold and curing, a process of removing the fabric member from the mold and cutting an excess portion to a predetermined size, The step of combining the fabric member cut into the dimensions of 1 to a predetermined product shape and stitching with a thread, and the step of fitting the fabric member stitched to the predetermined product shape into a resin impregnating mold, removing the shape-retaining material, and drying. And a step of filling a resin impregnating mold with a resin and curing the resin.

[0011]

In the method of manufacturing a composite material structure according to the present invention, a plurality of fabric members formed by divided molds are impregnated with a shape-retaining material and cured to cause misalignment and depressions on the fabric surface due to sutures. Without sewn, the fabric member containing no resin is sewn so that the resistance of the needle is reduced and no special device is required.
The sewn woven fabric member is dried while it is still attached to the resin impregnation mold, and the resin is impregnated and cured in that state to maintain the desired shape. The work environment and workability are improved because it is not present.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example in which the method for producing a composite material structure according to the present invention is applied to the production of a cylindrical product with a bottom. The method for producing a composite material structure is (a),
It is composed of 6 stages of (b), (c), (d), (e) and (f).

First step (a) of the method for manufacturing a composite structure
In, the cylindrical portion 1 (FIG. 3) of the bottomed cylindrical product is
For example, as shown in FIG. 2, the reinforcing fiber base material 2 obtained by laminating a woven fabric having a plain weave design or a satin weave design in accordance with the thickness of the product is wound around the outer peripheral surface 3a of the cylindrical molding die 3. The bottom portion 4 (FIG. 5) of the bottomed cylindrical product is formed by arranging the reinforcing fiber base material 2a so as to be in close contact with the bottom portion 5a of the cylindrical molding die 5. The plain woven fabric and satin woven fabric are used as the woven fabric because of their excellent formability.

Second step (b) of the method for manufacturing a composite structure
In the above, the reinforcing fiber base material 2 formed into a cylindrical shape by the cylindrical forming die 3 is coated and impregnated with a shape-retaining material, such as methyl cellulose, which does not adhere to the needle at the time of suturing, and is dried or cured to obtain a reinforcing fiber base material. The material 2 retains its shape. Similarly, the reinforcing fiber base material 2a formed by the bottom portion 5a of the cylindrical molding die 5 is coated and impregnated with a shape-retaining material such as methylcellulose, and dried or cured to retain the shape of the reinforcing fiber base material 2a. To do. For the drying or curing treatment of the reinforcing fiber base material 2 and the reinforcing fiber base material 2a which retain the shape, a method of covering the whole with a vacuum bag and heating and pressing with an autoclave or the like is suitable. Further, when it is necessary to prevent wrinkles from occurring in the molded product and improve the accuracy of the shape, it is desirable to use a resin impregnating mold, which will be described later.

The following table shows the experimental results of the amount of the shape-retaining material applied to the reinforcing fiber base material.

[0017]

[Table 1] In the third step (c) of the method for manufacturing a composite material structure,
The formed reinforcing fiber base material 2 is removed from the cylindrical molding die 3, and the peripheral excess thickness portion is cut. FIG. 3 shows a cylindrical portion 1 obtained by cutting the extra thickness portion. Similarly, the formed reinforcing fiber base material 2a is removed from the cylindrical molding die 5, and the peripheral excess thickness portion 2b is cut. The bottom portion 4 obtained by cutting the extra thickness portion 2b is shown in FIG. The shape-retaining material not only maintains the molded state of the reinforcing fiber base material, but also has the effect of preventing fraying of fibers and generation of dust at the time of cutting, and improves the cut surface.

Fourth step (d) of the method for manufacturing a composite structure
In, the cylindrical portion 1 and the bottom portion 4 are assembled so as to have predetermined dimensions and temporarily fixed. This can also be performed using a jig (not shown). As shown in FIG. 6, the cylindrical portion 1 and the bottom portion 4 assembled in this way are sewn together with a suture thread 6 at their joints with an industrial sewing machine to form a bottomed cylindrical product material 7. In the sewing process using the industrial sewing machine, the cylindrical portion 1 and the bottom portion 4 maintain the strength by the contained shape-retaining material, and the deformation of the parts due to the handling and sewing and the displacement of the parts do not occur, and the parts are accurately positioned. Sewn on. Unlike the sewing of prepreg, the sewing process is performed with the parts in a dry state by the industrial sewing machine, the resistance of the needle movement is small, the normal sewing is possible, and it is not necessary to provide an additional device for heating or vibration. .
Further, misalignment and dents on the surface of the reinforcing fiber substrate due to the suture thread can be completely prevented, and a uniform product can be formed.

Fifth step (e) of the method for manufacturing the composite structure
In FIG. 7, the bottomed cylindrical product material 7 is placed in the cleaning tank 8 so as to cover the support body 9 as shown in FIG. 7, and the cleaning liquid 10 is injected into the cleaning tank 8 to form the resin impregnating mold 8. Immersing the bottomed cylindrical product material 7 arranged in
The shape-retaining material impregnated in the bottomed cylindrical product material 7 is dissolved and removed by the cleaning liquid 10. The bottomed cylindrical product material 7 from which the shape-retaining material has been dissolved and removed is dried by a drying process (not shown). When the drying in this drying step is performed with the bottomed cylindrical product material 7 still covered with the support 9, the bottomed cylindrical product material 7 after the drying process is finished into a dry preform. Further, when it is necessary to prevent wrinkles from occurring in the molded product and to improve the shape accuracy, as shown in FIG.
There is a method of drying.

As another method for removing the shape retaining material of the bottomed cylindrical product material 7, there is a method of firing the bottomed cylindrical product material 7. This firing method is to remove the sizing agent applied to the fibers of the fabric,
This also removes the shape-retaining material.

Sixth step (f) of the method for manufacturing the composite structure
In FIG. 8, the bottomed cylindrical product material 7 is put into a resin impregnating female mold 11 as shown in FIG.
A resin is impregnated by the Transfer Molding method, and the resin is cured to form a bottomed cylindrical product.

[0022]

As described above, according to the present invention, since the parts are preliminarily molded and reinforced and integrally sewn, the suture does not cause misalignment or dents on the surface of the product and does not deform. Can be sewn while maintaining the above, and the dimensional accuracy of the assembled product is improved, and a product without wrinkles or fiber breakage can be molded.

[Brief description of drawings]

FIG. 1 is a block diagram showing a method for manufacturing a composite material structure according to the present invention.

FIG. 2 is a diagram showing a process of forming a cylindrical portion with a reinforcing fiber base material.

FIG. 3 is a view showing a reinforcing fiber base material formed into a cylindrical portion in FIG.

FIG. 4 is a diagram showing a step of molding a bottom portion with a reinforcing fiber base material.

FIG. 5 is a view showing a reinforcing fiber base material formed in the bottom portion in FIG.

FIG. 6 is a perspective view of a bottomed cylindrical product material in which a cylindrical portion 1 and a bottom portion 4 are sewn together.

FIG. 7 is a view showing an apparatus for removing a shape retention material from a bottomed cylindrical product material.

FIG. 8 is a view showing an apparatus for removing a shape-retaining material from a bottomed cylindrical product material.

FIG. 9 is a view showing an apparatus for impregnating and hardening a resin into a bottomed cylindrical product material.

[Explanation of symbols]

 1 Cylindrical part of bottomed cylindrical product 2 Reinforcing fiber base material 3 Cylindrical molding die 4 Bottom part of bottomed cylindrical product 5 Cylindrical molding die 7 Bottomed cylindrical product material 8 Cleaning tank 9 Support 9a Male mold for resin impregnation 11 Resin impregnation type

Claims (1)

[Claims] 1. A step of molding a plurality of woven fabric members by a molding die in which a reinforced fiber woven fabric laminated according to the thickness of a product is divided according to the shape, and a shape-retaining material with the woven fabric member held in the molding die. A step of impregnating and hardening the woven material, a step of removing the woven member from the molding die and cutting an extra portion so as to have a predetermined size, and combining the woven member cut to a predetermined size with a predetermined product shape And a step of fitting the woven fabric member sewn into a predetermined product shape to a resin impregnating mold to remove the shape-retaining material and drying, and a step of filling the resin impregnating mold with resin and curing the resin. A method for manufacturing a composite material structure having the following.