JPH07214708A - Manufacture of honeycomb sandwich structure and molding device - Google Patents

Abstract

PURPOSE:To provide favorable fitting properties to a jig surface and little thermal strain and prevent peeling by a warp during curing. CONSTITUTION:Pins 2 are arranged at specific intervals on an outer fringe part of the top of a laminating mold and a rest plate 3 which has a composite material prepreg for its material of the quality and a width with which arrangement of the pins is coated is placed so that the tip of the pin is thrusted into the rest plate 3, a composite prepreg of an outer skin, a honeycomb core and further a composite prepreg of an inner skin are placed on the laminating mold and they are piled are upon an other so that the honeycomb core is coated with the composite prepregs of both the skins. Then the pin is thrusted into a surplus thickness part where the prepregs of both the skins are piled upon each other, pressed by a weight so that a projected tip of the pin is inserted into a beltlike elastic material weight 4 and the honeycomb core and the prepreg of the skin are fixed and held.

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 honeycomb sandwich structure used as a structural member of an aircraft or the like and an apparatus for forming the honeycomb sandwich structure, and in particular, stacking a composite material prepreg and a honeycomb core on a stacking die and pressurizing them. The present invention relates to a method and a device for manufacturing a honeycomb sandwich structure manufactured by heating and curing.

[0002]

2. Description of the Related Art In recent years, a large number of composite materials structures have been incorporated mainly in aircraft for the purpose of weight reduction, and a typical example of such structures is a honeycomb sandwich structure using a composite material as a skin plate. This is a composite prepreg that is a semi-cured state in which a cloth woven of fibers of composite material such as glass, carbon, and aramid is impregnated with an epoxy resin, and a honeycomb of a predetermined shape is combined with an adhesive if necessary. It is manufactured by coating the core, pressurizing, and heat curing.

FIG. 9 shows an outline of a manufacturing process of such a honeycomb sandwich structure.

First, cleaning and the like are performed to prepare the laminated mold 1 (FIG. 9 (a)). Also, the honeycomb core is cut (see FIG. 9).
(B)), cutting of the prepreg (FIG. 9 (c)), etc. are prepared, and the laminate 1 is subjected to surface treatment such as aluminum frame spraying as necessary (FIG. 9).
(D)). Next, the prepreg and the honeycomb core are laminated on the laminated mold 1 (FIG. 9E). In this case, as shown in FIG. 8, the composite material prepreg 7 of the outer skin is first placed on the laminated mold 1 one by one or several layers while positioning. Then, the honeycomb core 8 is placed on the composite material prepreg 7 or the adhesive, and the composite material prepreg 9 having the inner skin is further laid on the honeycomb core 8 in the same manner. Cover with 7 and 9. In this case, since the honeycomb core 8 covered with the composite material prepregs 7 and 9 cannot be directly mechanically fixed, it is necessary to fix the honeycomb core 8 at the excess thickness portion 14 where the composite material prepregs 7 and 9 outside the core are polymerized. A vacuum covering film 11 is placed on the laminated layers, sealed with a seal 12 and evacuated from the die 13 for molding (FIG. 9F). Finally, it is cured by placing it in an autoclave together with the laminated mold 1 and heating it under pressure (FIG. 9 (g)).

In the case of a honeycomb sandwich panel in which the peripheral edge of the honeycomb core is finished with an inclination, the autoclave can pressure also acts on this inclined surface during pressurization and heating, so that the component force pushing in the lateral direction is increased. Occurs, and the resin softens as the temperature rises, and the frictional resistance between these and the honeycomb core becomes extremely small. As a result, there is a problem that slippage occurs in the honeycomb core and the quality of the product deteriorates. Various methods have heretofore been proposed to prevent such slippage of the honeycomb core and the prepreg.

Among them, the applicant of the present invention, as a pin strip type composite material forming jig, as shown in FIG. 8, has a surplus portion 14 where the composite material prepregs 7 and 9 outside the honeycomb core 8 are polymerized. The prepreg is pierced with the protrusion 15 and is sandwiched between the protrusion 15 and the elastic retainer 4, and the honeycomb core 8 is indirectly fixed by fixing the prepreg to the laminated mold, thereby fluidizing the resin of the prepreg. Accordingly, a forming jig for a honeycomb sandwich structure, which prevents the honeycomb core 8 from sliding in the arrow direction, is disclosed in Japanese Patent Publication No. 59-426.
No. 21 publication.

As shown in FIG. 6, in this molding jig, a mounting plate 5 is mounted in a square shape, for example, around the entire circumference of the laminated mold 1 corresponding to the position of the extra thickness portion, and the mounting plate 5 is entirely covered. The protrusions 15 are erected at predetermined intervals over the entire length.
In this case, the protrusion 15 is a pointed one having a conical base 15a as shown in FIG. 7, and if the mounting plate 5a is thin as shown in FIG. When the mounting plate 5b is bent and the mounting plate 5b is thick as shown in FIG. 7B, the supporting hole 16 is formed as it is, and the base 15a is engaged with the supporting hole 16 to integrally fix the mounting plate 15b to the mounting plate 15b. To be done. Further, as shown in FIG. 7C, it is disclosed that the protrusion 17 is formed by notching the mounting plate 15c in a V shape and bending a part of the notch.

[0008]

However, according to the structure of the jig, when the radius of curvature of the laminated die 1 is large, there is no problem in the conformability of the mounting plate 5 to the jig surface, but the radius of curvature is small. In this case, the conformability is reduced and molding defects are likely to occur. Further, due to the difference in the coefficient of thermal expansion between the mounting plate 5 and the laminated die 1 which contacts the lower surface of the mounting plate, there arises a problem that durability against a curing cycle is reduced.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, to have good conformability to the jig surface and to prevent peeling due to warpage during curing with little thermal distortion. It is an object of the present invention to provide a manufacturing method and a molding apparatus of a honeycomb sandwich structure which can be manufactured.

[0010]

In order to achieve the above-mentioned object, the present invention covers the entire circumference of a honeycomb core of a predetermined shape with a composite material prepreg on a laminated mold of fiber reinforced resin material and covers it with a vacuum bag. In the manufacturing method of forming a honeycomb sandwich structure by sealing and vacuuming and heating and curing, the upper surface of the stacking die is provided with pins at predetermined intervals on the outer peripheral edge portion, and a composite material prepreg is formed. A base plate made of a material and having a width that covers the arrangement of the pins is placed and cured so that the tips of the pins penetrate. The composite material prepreg of the outer skin, the honeycomb core, and the composite material prepreg of the inner skin are placed on the laminated type, and the composite prepreg of the both skins are overlapped so as to cover the honeycomb core, and the prepreg of the both skins is superposed. It is characterized in that the pin is pierced through the meat portion and the tip of the projecting pin is pressed by a presser adapted to be inserted into a band-shaped elastic material presser to fix and hold the honeycomb core and the skin prepreg. In the above method, it is preferable that a strip-shaped composite material prepreg is spread on the outer peripheral edge portion of the upper surface of the stacking type, and the pins are disposed on the outer peripheral edge portion at a specified interval with the dish portion facing downward.

In order to achieve the above-mentioned object, the present invention covers the entire circumference of a honeycomb core of a predetermined shape on a laminated mold of fiber reinforced resin material with a composite material prepreg, covers it with a vacuum bag and seals it. In a manufacturing apparatus for forming a honeycomb sandwich structure by applying a vacuum and heating and curing, pins arranged at a predetermined interval along the outer peripheral edge of the upper surface of the stacking die, and a width that covers the arrangement of the pins. A base plate cured from a composite material prepreg as a base material, a composite material prepreg in which overlapping overlapping portions are pierced by pins to cover the entire honeycomb core, and a tip is inserted so that it overlaps with the overlapping portions and the tips of the pins are inserted. It is characterized in that it is provided with a strip-shaped elastic material retainer. In the above-mentioned molding apparatus, it is preferable that a strip-shaped composite material prepreg is spread on the edge portion of the upper surface of the laminated die where the pins are arranged.

[0012]

According to the present invention, since the base plate is made of a composite material prepreg having excellent flexibility as a base material, the base plate fits well to the surface of the laminate even when the surface of the laminate has a small curvature. Also,
Even if pressure is applied by heating in an autoclave etc. after forming a vacuum bag and performing vacuuming, the base plate is a material of the same quality as the laminated type, so thermal stress can be prevented from occurring and peeling due to warpage during curing will occur. Etc. can be eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a honeycomb sandwich structure and a molding apparatus therefor according to the present invention will be described below with reference to the accompanying drawings. The same components as those of the conventional molding apparatus shown in FIG. 6 will be described with the same reference numerals.

FIG. 1 is a perspective view showing a molding apparatus for a honeycomb sandwich structure according to this embodiment. Match 1
Is a laminated die manufactured by laminating and curing carbon fabric material, and brass pins 2, 2, ... Are placed at regular intervals on the peripheral edge of the upper surface of the laminated die 1. There is. As the pin 2, a dish-shaped head pin is used, and the dish portion 2b is fixed to the upper surface of the laminated die 1. Further, the base plate 3 of the composite material prepreg having a width that covers at least the arrangement of the pins 2 is placed on the peripheral portion of the stacking mold 1 in a stacked manner and cured to obtain the base plate 3. The pin 2 is pierced through the base plate 3 so that the tip of the pin 2 projects. Reference numeral 4 indicates a presser for pressing a surplus portion of a composite material prepreg (not shown) which is superposed on the peripheral edge of the laminated die 1.

FIG. 2 is a sectional view taken along line AA of FIG. The dish 2b of the pin 2 fixed on the laminated die 1 is fixed to the upper surface of the laminated die 1, while the sharpened portion 2a of the pin 2 penetrates the composite base plate 3. Has been done. The gap between the pin 2 and the composite base plate 3 is sealed with the outflow resin 6.

Next, a method for manufacturing a honeycomb sandwich structure, which is carried out by using the above molding apparatus, will be described. FIG. 5 is a view showing a cross section of the honeycomb sandwich structure being formed by the vacuum bag method. A plurality of composite material prepregs 7 serving as outer skins are stacked on the surface of the stacking mold 1, and a honeycomb core 8 and an inner skin prepreg 9 are sequentially stacked thereon. In this way, the honeycomb core 8 is covered with the composite material prepregs 7 and 9 of the outer skin and the inner skin, and the bleeder cloth 10 is inserted between the prepreg layers in the extra thickness portion 14 where both prepregs 7 and 9 are superposed at their ends. While piercing pins 2, 2, ...

Next, the presser 4 made of an elastic material such as heat-resistant rubber or plastic of 180 ° or more and having substantially the same shape as the composite base plate 3 is placed on the uppermost portion of the extra thickness portion 14. The presser foot 4 is pressed against the extra thickness portion 14, and the pin 2,
2. While inserting, press and fix. As a result, the composite material prepregs 7 and 9 are securely fixed to the laminated mold 1 by being pinched by the pin 2 and the presser 4. In this case, the base plate 3 is made of a material similar to the jig material using the composite material prepreg as a base material, and even if the radius of curvature of the surface of the stacking mold 1 is small, it fits well to the surface of the stacking mold 1 so that the jig is manufactured. Is easy. Moreover, since the layers of the prepregs 7 and 9 are collectively fixed by the pins 2 and the presser 4 at a position close to the honeycomb core 8, the indirect fixing effect of the honeycomb core 8 becomes extremely large. In this way, the laminate of the prepregs 7 and 9 and the honeycomb core 8 is completely held so as not to come off. Thereafter, as in the conventional composite material molding method, the covering film 11 is covered, the entire circumference is sealed by the seal 12, and the vacuum suction work is performed by the vacuum suction cap 13. In this case, the air remaining in the crimping portion 14 of the prepreg formed by the pin 2 and the presser 4 is effectively removed by the bleeder cloth.

In this way, after forming a vacuum bag and performing vacuuming, it is pressurized and heated in an autoclave or the like. At this time, since the composite base plate 3 is made of the same material as the laminated die 1, it is possible to prevent the occurrence of thermal stress and prevent peeling or the like. Therefore, as described above, since the honeycomb core is securely fixed and held, the honeycomb core fixed between them is integrally bonded and cured without slippage.

Next, FIG. 3 shows another embodiment. In the second embodiment, a composite material prepreg 3a having the same width as the pin fixing composite material base plate 3b is laid on the upper surface of the laminated die 1, and the pointed head 2a of the pin 2 is projected on the composite material prepreg 3a. The composite material prepreg is piled up to form the composite material base plate 3b, and the pin 2 is formed.
Is to be placed. The gap between the pin 2 and the composite base plate 3b is sealed with the outflow resin 6, and the dam effect of the composite prepreg has the effect of preventing the outflow of the resin of the composite product from the first embodiment and the third embodiment described later. You can expect more than the examples.

FIG. 4 is a diagram showing still another third embodiment. After the composite material prepreg is laid out to form the separable composite material base plate 3c on the laminated die 1, the pins are placed thereon, and further, the composite material base plate 3b projects the point 2a of the pin 2 upward. It is a cured product. The gap between the pin 2 and the composite base plate 3b is sealed with the outflow resin 6. In this way, by making the laminated mold 1 and the composite surface plate 3c separable, even when the materials of the laminated mold 1 and the composite material prepreg are different, the sliding action between the laminated surface plates and the composite surface plate Three
Since the c-composite prepreg 7 has the same coefficient of thermal expansion, even if the laminated type and the composite prepreg are made of different materials, a large structure can be easily dealt with.

[0021]

As is apparent from the above description, according to the present invention, since the base plate of the composite material prepreg of the same quality as the laminated type is used as the base material of the pin, even when the laminated type has a small radius of curvature. Well familiar, workability improved, pin,
The fixation of the epidermis by the presser foot is ensured. Further, since the generation of thermal stress can be prevented during curing, peeling due to warpage is eliminated, which is effective in reducing repair processes and inspection processes.

[Brief description of drawings]

FIG. 1 is a perspective view of a honeycomb sandwich structure molding apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a cross-sectional view showing a fixing structure of a pin and a composite material prepreg in a honeycomb sandwich structure molding apparatus according to a second embodiment.

FIG. 4 is a cross-sectional view showing a fixing structure of a pin and a composite material prepreg in a honeycomb sandwich structure molding apparatus according to a third embodiment.

FIG. 5 is a cross-sectional view of the honeycomb sandwich structure in a process of vacuuming with a vacuum bag.

FIG. 6 is a perspective view of a conventional apparatus for forming a honeycomb sandwich structure.

FIG. 7 is a view showing a structure of a protrusion provided with a laminated type,
(A) is sectional drawing, (b) is sectional drawing of another example, (c) is a perspective view of another example.

FIG. 8 is a cross-sectional view of the honeycomb sandwich structure in a vacuuming process.

FIG. 9 is an explanatory view showing a manufacturing process of the honeycomb sandwich structure.

[Explanation of symbols]

 1 laminated type 2 pin 3 composite material base plate 4 presser 6 outflow resin 7 composite material prepreg 8 for outer skin 8 honeycomb core 9 composite material prepreg for inner skin 10 bleeder cloth 11 cover film 12 seal 13 vacuum puller 14 surplus part

Claims (4)

[Claims] 1. A honeycomb sandwich obtained by covering the entire circumference of a honeycomb core of a predetermined shape with a composite material prepreg on a laminated type of fiber reinforced resin material, covering with a vacuum bag, sealing, vacuuming, heating and curing. In the manufacturing method of molding a structure, the pins are arranged at a predetermined interval on the outer peripheral edge of the upper surface of the laminated die, and a base plate having a width that covers the array of the pins using the composite material prepreg as a base material is provided for the pins. Place it so that the tip pierces and cure it, and put the composite prepreg of the outer skin on the laminated type, the honeycomb core, and the composite prepreg of the inner skin, and cover the honeycomb core with the composite prepreg of the both skins. Overlap, while pushing the pin through the excess thickness portion where the prepregs of the both skins are superposed, the tip of the protruding pin is pushed into the band-shaped elastic material retainer and pressed by the retainer honeycomb The method for manufacturing a honeycomb sandwich structure, characterized in that fixing and holding the prepreg A and the skin. 2. The method for manufacturing a honeycomb sandwich structure according to claim 1, wherein a strip-shaped composite material prepreg is spread on an outer peripheral edge portion of the upper surface of the laminated die, and the pin and the dish portion thereof are provided thereon. A method for manufacturing a honeycomb sandwich structure, characterized in that the honeycomb sandwich structure is arranged downward at a specified interval. 3. A honeycomb sandwich obtained by covering the entire circumference of a honeycomb core of a predetermined shape on a laminated type of fiber reinforced resin material with a composite material prepreg, covering with a vacuum bag, sealing, vacuuming, heating and curing. In a manufacturing apparatus for molding a structure, pins arranged at a predetermined interval along the outer peripheral edge of the upper surface of the stacking mold, and a composite material base plate having a composite material prepreg of a width covering the arrangement of the pins as a base material. A composite material prepreg in which overlapping margin portions are pierced by the pins to cover the entire honeycomb core, and a strip-shaped elastic material retainer that is attached so as to be inserted into the margin portions so that the tips of the pins are inserted. An apparatus for forming a honeycomb sandwich structure characterized by: 4. The honeycomb sandwich structure forming apparatus according to claim 3, wherein a strip-shaped composite material prepreg is spread on an edge portion of the upper surface of the laminate where the pins are arranged. Structure forming equipment.