RU2603798C1 - Method of forming articles of composite material - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to method of forming articles of composite material. Technical result is achieved by method of forming articles of composite material, which involves lining of fibrous material, impregnated with binder, in recess of production equipment and use of sealing elements of thermally expanding rubber to create molding pressure, package, heating, supply of pressure, cooling of hardened product and its extraction from tooling fixture. Wherein volume of tooling cavities is equal to or greater than volume of non-compacted fibrous material, impregnated with binder, forming article. Sealing element is made of strip-like uncured thermally expanded rubber covering recess of tooling. Wherein pressure is transmitted to rubber element via stiff saddle overlapping strip of uncured rubber, which partially fills tooling cavity during heating and pressure supply via saddle, thus sealing fibrous material, impregnated with binder and creating molding pressure during curing.

EFFECT: technical result is reduced labor input, power consumption and shorter production cycle of making article.

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Description

The invention relates to methods of molding products from composite materials, in particular to methods of compaction of composite material, and can be used to obtain structures in aviation and space technology.

In the patent of the Russian Federation No. 2372195 C1 dated 03/21/2008 a method for molding articles of complex configuration is described, in which a set of products is made of polymer composite materials in a matrix (mold), then the internal cavity of the part is filled with a compound, the compound is polymerized and the part is cured.

This method requires pre-production of the punch before molding the product and the introduction of an additional operation of the polymerization of the compound, which increases the complexity and production cycle of manufacture.

Closest to the invention is the combined method of molding described in the training manual "Polymer composite materials: structure, properties and technology. Textbook benefits - 4th rev. and add. ed. / Ed. A.A. Berlin - M .: CCP "Profession"; 2014 - 522-523 s. ". The method combines thermocompression and autoclave molding, in which rubber inserts, which act as sealing elements, are placed in a form with a prepreg, hermetically packed and the molding mode is carried out in an autoclave. As a result, the compaction of the material during curing occurs due to external pressure and thermal expansion of rubber.

The disadvantages of this molding method is the great complexity and a long manufacturing cycle, due to the need for pre-manufacturing of liners and additional devices for their molding, as well as the need to use energy-intensive equipment (autoclave) to provide molding pressure.

The objective of the invention is to reduce the complexity, energy intensity and shorten the production cycle by eliminating the preliminary manufacture of liners and additional devices for their molding, as well as the possibility of using less energy-intensive equipment.

A method of molding articles of composite material, including laying out a fiber-impregnated binder material into a recess of a tooling and using sealing elements of thermally expanding rubber to create molding pressure, packaging, heating, applying pressure, cooling the cured article and removing it from the tool, is characterized in that the volume the deepening of the tooling is made equal to or greater than the volume of the unconsolidated binder-impregnated fibrous material forming o the product, the sealing element is made of unvulcanized thermally expanding rubber in the form of a strip that overlaps the technological equipment depression, and the pressure on the rubber element is transmitted through a rigid tsulag overlapping the strip of unvulcanized rubber, which partially fills the technological equipment depression during heating and pressure supply through the tsulag, compaction of the binder-impregnated fibrous material and creating a molding pressure upon curing.

It is advisable to carry out the depth of the technological tooling in excess of the volume of the unconsolidated binder-impregnated fibrous material forming the product by no more than 10%.

The sealing element may overlap the recess by at least 5 mm on each side.

A rigid pulp overlapping a strip of unvulcanized rubber can be made in such a way that the ratio of the area of a rigid pulp overlapping a strip of unvulcanized rubber to the area of this strip is equal to the ratio of the pressure required to form the product to the pressure applied to a rigid pulp during curing products.

The implementation of the volume of deepening technological equipment equal to or more than the volume of uncompressed binder-impregnated fibrous material forming the product, using a sealing element made of unvulcanized heat-expanding rubber in the form of a strip overlapping the recess of technological equipment, while transmitting pressure to the rubber element through a rigid tsulag overlapping the strip of unvulcanized rubber, which in the process of heating and applying pressure through the tsulag partially fills the deeper the use of technological equipment, compacting the fiber material impregnated with a binder and creating a molding pressure during its curing, reduces laboriousness and shortens the production cycle by eliminating the operations of preliminary manufacturing of inserts and using additional devices for their molding, as well as reducing the energy consumption of manufacturing due to the possibility of eliminating energy-intensive equipment (autoclave).

The implementation of the volume of deepening technological equipment in excess of the volume of the unconsolidated impregnated with a binder of the fibrous material forming the product, not more than 10% allows for the necessary molding pressure to facilitate the laying out of the product, which reduces the complexity of manufacturing.

Ensuring that the sealing element overlaps the recesses by at least 5 mm on each side makes it easier to install sealing elements, which reduces the complexity of manufacturing.

The use of a rigid tsulag overlapping the strip of unvulcanized rubber, so that the ratio of the area of the tough tsulag overlapping the strip of unvulcanized rubber to the area of this strip is equal to the ratio of the pressure required for molding the product to the pressure applied to the rigid tsulag during the curing process of the product, allows the molding process to create pressure on the material several times more than on tsulag, which eliminates the need for energy-intensive equipment (autoclave), reducing energy manufacturing capacity.

The invention is illustrated by drawings.

In FIG. 1 presents a diagram of the main elements intended for the implementation of the proposed method, before molding.

In FIG. 2 presents a diagram of the main elements intended for the implementation of the proposed method in the molding process.

In FIG. 3 presents a product molded by the proposed method

The method is carried out in the following sequence.

Spread the binder-impregnated fibrous material 1 into the recess 2 of the tooling 3. The recess of the tooling 3 is covered with a sealing element 4 made of unvulcanized heat-expanding rubber in the form of a strip. Then a rigid tsulag 5 is installed, covering the strip of unvulcanized rubber, the equipment is hermetically sealed and the product is molded. During molding, pressure on the sealing element is carried out through a rigid tsulag. In the process of heating T and applying pressure P, a partial filling of the tooling cavity with rubber occurs with the formation of a forming rubber insert 6, which compacts the fibrous material 1 and creates pressure during curing of the product 7.

Example

The proposed method of molding products from composite materials is implemented in the manufacture of ribs representing a profiled truss structure for an unmanned aerial vehicle. HTS-40 carbon fiber material impregnated with Araldite 8615 / Aradur 8615 epoxy binder was laid in 6 × 3 mm and 6 × 2 mm metal tool pits. Strips of unvulcanized rubber IRP-1399 15 mm wide and 3 mm thick were laid along the contour of the cavity. A hard metal plate was installed on top of the rubber with an area exceeding the total area of strips of unvulcanized rubber by 5 times. Then they were packed in a vacuum bag and cured in an oven at a temperature of 150 ± 5 ° C and a vacuum pressure of 0.8 ... 1 atm, after which they were pressed and the product was removed.

The proposed method of molding products from composite materials can reduce the complexity, energy intensity and shorten the production cycle by eliminating the preliminary manufacture of liners and additional devices for their molding, as well as the possibility of using less energy-intensive equipment.

Claims (4)

1. A method of forming articles of composite material, including laying out a fiber-impregnated binder material into a recess of a tooling and using sealing elements of thermally expanding rubber to create molding pressure, packaging, heating, applying pressure, cooling the cured article and removing it from the tool, characterized in that the depth of the technological tooling is equal to or greater than the volume of the unconsolidated binder-impregnated fibrous material, forming For the product, the sealing element is made of unvulcanized thermally expanding rubber in the form of a strip overlapping the recess of the tooling, and the pressure on the rubber element is transmitted through a rigid tsulag overlapping the strip of unvulcanized rubber, which partially fills the recess of the technological equipment during heating and applying pressure through the tsulag, compaction of the binder-impregnated fibrous material and creating a molding pressure upon curing. 2. The method according to p. 1, characterized in that the volume of the deepening of the technological equipment exceeds the volume of the unconsolidated binder-impregnated fibrous material forming the product by no more than 10%. 3. The method according to p. 1, characterized in that the sealing element overlaps the recess by at least 5 mm on each side. 4. The method according to p. 1, characterized in that the ratio of the area of the hard tsulag overlapping the strip of unvulcanized rubber to the area of this strip is equal to the ratio of the pressure necessary for molding the product to the pressure applied to the hard tsulag during the curing of the product.

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