CN110815875A - A kind of molding method of composite honeycomb sandwich structure parts - Google Patents

Abstract

The invention discloses a forming method of a composite material honeycomb sandwich structure part, which comprises the steps of tool preparation, paving and pasting of demolding cloth, paving and pasting of a part layer, pressing plate packaging, curing and forming and the like. The forming tool for the honeycomb sandwich part with the rubber layer with the flexible function on the surface is used for uniformly and accurately transmitting the pressure of the autoclave to the inner skin of the honeycomb sandwich part, so that the condition that a honeycomb core is pressed too much to cause slippage and even collapse is avoided; in addition, the flexible rubber layer in the forming tool allowance area can play a role of an anti-slip belt, so that the inner skin prepreg is prevented from sliding in the curing process, and the forming quality of the honeycomb sandwich part is further influenced. Therefore, the forming method has simple process and easy control, and can greatly improve the forming quality and the qualification rate of the composite material honeycomb sandwich structure parts.

Description

A kind of molding method of composite honeycomb sandwich structure parts

technical field

The invention relates to a molding method of a composite material honeycomb sandwich structure part.

Background technique

The composite honeycomb sandwich structure is generally composed of a lightweight honeycomb core in the middle and skins on the upper and lower surfaces. The core layer has a low density and only bears transverse shear loads, increasing the stiffness of the structure. The composite sandwich structure has the advantages of low density, high bending stiffness, strong anti-instability stability, thermal insulation and sound insulation, etc., so it has been widely used in aerospace non-main load-bearing structures.

The existing preparation method of the composite honeycomb sandwich structure mainly adopts the molding process of co-curing, secondary bonding and co-bonding on the molding tool. The traditional molding die has high rigidity and uneven pressure transmission, while the honeycomb core is a thin-walled and elastic structure. When the honeycomb core is compressed, due to the excessive local pressure, it squeezes with the rigid molding die, and the interaction force is too high. Ambassador honeycomb core is prone to slippage, even tearing, wrinkling, collapse and other bad conditions. In order to ensure that the honeycomb core does not slip during molding, the pressure should not be too large when entering the tank for curing, but the pressure is low and the pressure is low when the skin is formed. The distribution is uneven, and the inner quality of the skin is difficult to control.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the above-mentioned preparation method of the existing composite honeycomb sandwich structure, the present invention provides a molding method of a composite honeycomb sandwich structure part, which aims to solve the situation that the honeycomb slips or even collapses when the pressure is too large during the curing process. If the pressure is too small, the quality of the inner and outer skins is not qualified, so as to improve the molding quality and product qualification rate of the composite honeycomb sandwich structure parts. The specific technical solutions are as follows:

A method for forming a composite honeycomb sandwich structure part, comprising the following steps:

1) Tooling preparation: The rigid structure and flexible structure of the honeycomb sandwich structure parts forming tooling are compositely connected into a whole to form the forming tooling of the honeycomb sandwich parts;

2) Lay the release cloth: Lay the release cloth on the part forming area of the forming tool described in step 1), and use acetone to clean the surface;

3) Lay the parts and build the layer: lay the preparation material of the composite honeycomb sandwich structure part on the demoulding cloth cleaned in step 2), and vacuumize it to pre-compact it;

4) Pressing plate packaging: Select a pressure equalizing plate of appropriate thickness, clean its surface with acetone, and cover it on the pre-compacted part material in step 3); then encapsulate the equalizing plate and the honeycomb sandwich part material on the molding tool ;

5) Curing and molding: The parts and tooling packaged in step 4) are sent to the autoclave for curing and molding, and the mold is released after the can to obtain honeycomb sandwich parts with good quality.

As a preferred technical solution, in step 1), the rigid structure is made of metal material or metal and carbon fiber composite material; the flexible structure is rubber with flexible function, which is connected by vulcanization, film connection or co-curing The connection method is attached to the surface of the rigid structure.

When the rigid structure is made of metal material, its surface needs to be cleaned and modified before use. After it is attached to the rubber, a vacuum bag is made on the surface of the rigid structure with a sealing tape, and then vacuumed on the metal surface. Negative pressure is formed between the material and the rubber, so that the rubber is evenly pressed on the surface of the rigid structure; then, the rigid structure and the rubber are packaged together and placed in a vulcanization tank for vulcanization connection, that is, a forming tool for honeycomb sandwich parts. Further, the reagent used in the modification treatment is a silane coupling agent; the conditions for the vulcanization connection are: the vulcanization temperature is 180° C. and the vulcanization time is 2 hours.

When the rigid structure is made of metal and carbon fiber composite material, after it is attached to the rubber, a vacuum bag is made on the surface of the rigid structure with a sealing tape, and is compacted by vacuum heat, and then the carbon fiber prepreg is laid and Packaged, and then sent to an autoclave for co-curing connection, that is, forming a molding tool for honeycomb sandwich parts. Further, the number of layers of the carbon fiber prepreg is 5 layers; the conditions of the co-curing connection are: the co-curing pressure is 0.6 MPa, the co-curing temperature is 180°C, and the co-curing time is 2 h.

As a further preferred technical solution, the rubber with flexible function is silicone rubber, and its thickness is 1-2 mm.

In addition, as a preferred technical solution, in step 2), when laying the mold release cloth, a margin area of 10-20 mm is left on the edge of the part forming area as a non-slip tape for laying honeycomb sandwich parts.

As a preferred technical solution, in step 3), the part preparation materials are laid in order of inner skin prepreg layer, inner adhesive film layer, honeycomb core, outer adhesive film layer and outer skin prepreg layer.

As a preferred technical solution, in step 4), the pressure equalizing plate is a thin aluminum plate or a carbon fiber laminate, and its thickness is 0.5 mm.

The beneficial effects of the present invention are:

The invention lays a rubber layer on the molding die, makes full use of the elasticity of the rubber, so that the covering surface of the rubber layer can transmit the pressure exerted by the autoclave evenly and accurately without causing the honeycomb core to be too compressed to cause slippage or even collapse. It effectively solves the problem that the honeycomb slips or even collapses when the pressure is too large in the traditional curing process, and the quality of the inner and outer skins is unqualified when the pressure is too small.

In addition, when laying the release cloth, there is a margin area around the molding area of the part. The rubber layer in the margin area effectively acts as a "slip strip" for the prepreg of the honeycomb sandwich part to reduce the inner skin. slip.

In addition, the laminate ensures that the outer surface quality of the outer skin of the composite honeycomb sandwich structure part is smooth and scratch-free. Therefore, the molding method of the present invention can realize the integrated molding preparation of the composite honeycomb sandwich structure parts with high quality and high qualification rate, which not only ensures that the honeycomb molding does not slip, but also improves the molding quality of the inner and outer skins.

Description of drawings

FIG. 1 is a schematic diagram of the assembly of the composite honeycomb sandwich structure part and the forming tool according to the present invention (wherein, the rigid structure of the forming tool is made of metal material);

Fig. 2 is the structural schematic diagram of the composite honeycomb sandwich structure part of the present invention;

Fig. 3 is another schematic diagram of the forming tool for the composite honeycomb sandwich structure part of the present invention (wherein, the rigid structure of the forming tool is made of metal and carbon fiber composite material).

In the figure: 1. Forming tool; 2. Rigid structure; 3. Flexible structure; 4. Release cloth; 5. Anti-skid belt; 6. Composite honeycomb sandwich structure parts; 7. Pressure equalizing plate; 8. Prepreg layer; 9. Adhesive film; 10. Honeycomb core; 11. Carbon fiber prepreg layer; 12. Vacuum packaging; 13. Insulating tape.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

The present embodiment provides a molding method for a composite honeycomb sandwich structure part, comprising the following steps:

1) Tooling preparation: First, the rigid structure (2) of the forming tooling (1) of the composite honeycomb sandwich structure part is fabricated by machining. In this embodiment, the rigid structure (2) is made of metal material. After the metal rigid structure is prepared, the surface is cleaned first, and then the surface is modified with a silane coupling agent to enhance the vulcanization connection performance with the rubber. Then, 1mm thick unvulcanized silicone rubber is placed on the surface of the metal rigid structure as a flexible structure (3) of the forming tool, and a sealing tape (13) is used to form a vacuum package (12) on the surface of the metal rigid structure, which is formed by vacuuming A negative pressure presses the rubber evenly on the surface of the metal structure; then the silicone rubber is encapsulated with the metal rigid structure, placed in a vulcanization tank as a whole, and vulcanized at 180°C for 2 hours, so that the silicone rubber and the metal rigid structure are vulcanized and connected. After canning, the forming tooling for honeycomb sandwich parts is formed, as shown in Figure 1.

2) Lay the release cloth: Lay the release cloth (4) on the part forming area on the surface of the forming tool (1) prepared in step 1), pay attention to leave a 10mm margin area on the edge of the part forming area and not lay it The release cloth is used as a non-slip tape (5) for forming the honeycomb sandwich part, and the surface of the release cloth is cleaned with acetone after the application is completed.

3) Laying the parts and layers: In step 2), the surface of the molding tool (1) with the release cloth (4) is laid in sequence, and the layers of the composite honeycomb sandwich structure parts (6) are laid in sequence, which are as follows: Inner skin prepreg layer (81), inner adhesive film layer (91), honeycomb core (10), outer adhesive film layer (92), outer skin prepreg layer (82); then pre-compacted by vacuuming shape, as shown in Figure 2.

4) Press plate encapsulation: choose a thin aluminum plate with a thickness of 0.5 mm as the pressure equalizing plate (7), clean its surface with acetone, and then cover the outer skin prepreg layer (82) of the honeycomb sandwich part laid in step 3). ) surface, encapsulate it and honeycomb sandwich parts on the forming tool (1) using auxiliary materials such as vacuum bags and air felt isolation films.

5) Curing and molding: The parts and tooling packaged in step 4) are sent into the autoclave to be cured and molded, and the honeycomb sandwich parts with good quality can be obtained after the cans are demolded.

Example 2

The present embodiment provides a molding method for a composite honeycomb sandwich structure part, comprising the following steps:

1) Tooling preparation: The rigid structure (2) of a molding tool (1) of a composite honeycomb sandwich structure part is also fabricated by machining, and the rigid structure (2) is a metal male mold, and its upper profile and composite Material The shape and size of the honeycomb sandwich structure parts are consistent with the metal. After the male molding is finished, a layer of 2mm silicone rubber is firstly spread on its surface as a flexible structure (13) of the molding tool, and a vacuum package (12) is formed on the surface of the metal rigid structure by using a sealing tape (13). The two are compacted by vacuum; then 5 layers of carbon fiber prepreg layers (11) are laid on the surface, packaged with auxiliary materials such as vacuum bags, and then sent to an autoclave at 0.6MPa and co-cured at 180°C After 2 hours, the silicone rubber and the carbon fiber prepreg are co-cured and connected to form a molding tool (1) for the honeycomb sandwich part, as shown in Figure 3.

2) Lay the release cloth: Lay the release cloth (4) on the rubber surface of the rubber surface of the molding tool (1) prepared in step 1), and pay attention to leave a 10mm margin area on the edge of the part forming area. A release cloth is attached, and the non-slip tape (5) for forming is applied as the honeycomb sandwich part, and the surface of the release cloth (4) is cleaned with acetone after the application is completed.

3) Laying the parts and layers: In step 2), the surface of the molding tool (1) with the release cloth (4) is laid in sequence, and the layers of the composite honeycomb sandwich structure parts (6) are laid in sequence, which are as follows: Inner skin prepreg layer (81), inner adhesive film layer (91), honeycomb core (10), outer adhesive film layer (92), outer skin prepreg layer (82); then pre-compacted by vacuuming shape, as shown in Figure 2.

4) Press plate encapsulation: use a carbon fiber laminate with a thickness of 0.5 mm as the pressure equalizing plate (7), preferably carbon fiber fabric or carbon fiber unidirectional tape laminate; use acetone to clean the surface of the pressure equalizing plate, and then cover it in step 3) The surface of the outer skin prepreg layer (82) of the laid honeycomb sandwich part is then packaged with the honeycomb sandwich part on the forming tool (1) using auxiliary materials such as vacuum bags and air felt isolation films.

5) Curing and molding: The parts and tooling packaged in step 4) are sent to the autoclave for curing and molding, and the honeycomb sandwich parts with good quality can be obtained by demoulding after the can.

It will be apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, but that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments are to be regarded in all respects as illustrative and not restrictive, and the scope of the invention is to be defined by the appended claims rather than the foregoing description, which are therefore intended to fall within the scope of the claims. All changes within the meaning and scope of the same requirements are included in the present invention. Any reference signs in the claims shall not be construed as limiting the involved claim.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. a molding method of a composite honeycomb sandwich structure part, is characterized in that: comprise the steps as follows: 1) Tooling preparation: The rigid structure and flexible structure of the honeycomb sandwich structure parts forming tooling are compositely connected into a whole to form the forming tooling of the honeycomb sandwich parts; 2) Lay the release cloth: Lay the release cloth on the part forming area of the forming tool described in step 1), and use acetone to clean the surface; 3) Lay the parts and build the layers: lay the building materials of the composite honeycomb sandwich structure parts on the demoulding cloth cleaned in step 2), and vacuumize them to pre-compact them; 4) Press plate encapsulation: Select a pressure equalizing plate of appropriate thickness, clean its surface with acetone, and cover it on the pre-compacted part layering material in step 3); on tooling; 5) Curing and molding: The parts and tooling packaged in step 4) are sent to the autoclave for curing and molding, and the mold is released after the can to obtain honeycomb sandwich parts with good quality. 2 . The molding method for composite honeycomb sandwich structure parts according to claim 1 , wherein: in step 1), the rigid structure is made of metal material or metal and carbon fiber composite material; the flexible structure has The flexible functional rubber is attached to the surface of the rigid structure by means of vulcanization connection, adhesive film connection or co-curing connection. 3. The molding method of composite honeycomb sandwich structure parts according to claim 2, characterized in that: the rigid structure is made of metal material, and its surface needs to be cleaned and modified before use, and attached to rubber Then, a vacuum bag is made on its surface with a sealing tape, and then a negative pressure is formed between the metal material and the rubber by vacuuming, so that the rubber is evenly pressed on the surface of the rigid structure; then, the rigid structure and the rubber are packaged together It is placed in a vulcanization tank for vulcanization connection, that is, a forming tool for honeycomb sandwich parts is formed. 4. The molding method of composite honeycomb sandwich structure parts according to claim 3, characterized in that: the reagent used in the modification treatment is a silane coupling agent; the conditions for the vulcanization connection are: the vulcanization temperature is 180 ℃, the curing time is 2h. 5 . The molding method of composite honeycomb sandwich structure parts according to claim 2 , wherein the rigid structure is made of metal and carbon fiber composite materials, and after it is attached to the rubber, a sealing tape is used on its surface. 6 . It is made into a vacuum bag and compacted by vacuum; then carbon fiber prepreg is laid and packaged, and then sent to an autoclave for co-curing connection, that is, a molding tool for honeycomb sandwich parts is formed. 6 . The molding method of composite honeycomb sandwich structure parts according to claim 5 , wherein: the number of layers of the carbon fiber prepreg is 5 layers; the condition of the co-curing connection is: co-curing pressure is 0.6MPa, the co-curing temperature is 180 ℃, and the co-curing time is 2h. 7 . The molding method for composite honeycomb sandwich structure parts according to claim 2 , wherein the rubber with flexible function is silicone rubber, and its thickness is 1-2 mm. 8 . 8 . The method for forming a composite honeycomb sandwich structure part according to claim 1 , wherein in step 2), when laying the mold release cloth, there are 10-20 mm of space left on the edge of the part forming area. 9 . The margin area is used as a non-slip tape for laying honeycomb sandwich parts. 9 . The method for forming a composite honeycomb sandwich structure part according to claim 1 , wherein in step 3), the laying order of the component layer materials is the inner skin prepreg layer and the inner adhesive film layer in sequence. 10 . , honeycomb core, outer film layer and outer skin prepreg layer. 10 . The method for forming a composite honeycomb sandwich structure part according to claim 1 , wherein in step 4), the equalizing plate is a thin aluminum plate or a carbon fiber laminate, and its thickness is 0.5 mm. 11 .

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