RU2694352C1 - Method of repairing articles from polymer composite materials - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to repair of articles from polymer composite materials. Technical result is achieved by a method of repairing articles from polymer composite materials, which includes removing the damaged part from the surface of the article at the point of the defect. Repaired section is cleaned with technical low-boiling solvent – acetone with degree of purity of puriss. p.a. or c.p. Two sheets of carbon fabric are laid on top of defect place, on each other, along which adhesive tape is attached around contour along distance from them. Product surface between adhesive tape and sheets of carbon fabric is treated with anti-adhesion composition. Then adhesive tape is removed and in its place is glued in two rows sealing bundle. Inside the contour formed by the sealing bundle, a layer of sacrificial material is placed over the sheets of carbon fabric, on top of which a distribution grid is placed. Binder feed line is placed on top of the distribution grid. Obtained structure is covered with two layers of a vacuum film, the edges of each of which layers are fixed along the entire perimeter by means of a corresponding sealing bundle with formation of the corresponding vacuum package. Each of the assembled vacuum packages is connected by means of its vacuum line to the corresponding pump, and vacuum is created in each of the said vacuum packages. Binder feed line is used to feed the epoxy binder and impregnate them with carbon cloth sheets. Epoxy binder is then cured at room temperature for 24 hours. After that, vacuum film, binder feed line, distribution grid and sacrificial material are removed, and post-hardening of article at 180 °C, the repaired section of the article is ground to obtain a smooth working surface.

EFFECT: easier repair of the articles without using heating and higher quality of repair.

6 cl, 1 dwg

Description

The invention relates to the field of engineering, can be used for the repair and restoration of composite products that have a defect, in particular, tooling, intended for the molding of products from polymer composite materials (PCM), and find application in aerospace, automotive, shipbuilding and other industries.

Snap-in is one of the key components of the production technology of PCM, because it sets the shape of the resulting product.

To date, the most suitable material for the manufacture of tooling for the molding of polymer composite materials (PCM) are also PCM, thanks to the possibility of meeting the high requirements for tolerances and deformations of the most important products of aviation and other equipment manufactured on them. The advantages of composite tooling are the proximity of their properties to the properties of the molded part, less weight and cost compared to, for example, snap-in metal. In addition, a number of operational requirements are imposed on the equipment, on which the period of its use depends, in particular, high hardness and preservation of the surface shape, tightness for molding high-quality parts on it. Long-term operation of composite equipment, a large number of removal of target products from it, as well as possible mechanical effects can lead to the appearance of various defects in its working surface, such as scratches, dents, cracks, with possible subsequent loss of its tightness.

There is a method of repairing products from polymer composite materials, which is characterized in that the damaged part is removed from the surface of the product, the damaged part is glued around the defect area along the contour with a sealing bundle, inside the contour formed by the sealing bundle, a layer of sacrificial material is laid, the resulting construction is covered with a vacuum layer the film, the edges of which are fixed along the entire perimeter by means of a sealing bundle with the formation of the corresponding vacuum package, assembled vacuum This package is connected via a vacuum line to a pump (application US 20170028655, VS 73/08, 02.02.2017). This method is adopted as a prototype. In this method, before assembling a vacuum bag, in place of a product defect, from the surface of which the damaged part is removed by machining, a composite repair part is placed, which is a stack of pre-impregnated fiber layers, before installing the specified repair part, this last and / or the surface of the product to be repaired is coated with resin, which facilitates the connection of the repair part with the repaired surface of the product. For polymerization and sealing of the repair part and its successful attachment to the product surface, a heating cover is installed between the vacuum bag and the repair part at the defect site, and a pressure plate placed on top of the vacuum bag and at least one tension belt is used to preload the repair part tension.

The technical problem of the method described above is the complexity of the equipment for its implementation, the need to heat the repair part for its gluing, the complexity of the process of disassembling the equipment after fixing the repair part on the surface of the product.

The technical result is achieved by means of a method of repairing products from polymer composite materials, characterized in that the damaged part is removed from the product’s surface to a depth (h) at the defect site, the repaired area is cleaned with a technical low-boiling solvent (such as acetone with purity grade etc. or h.ch.), on top of the place of defect lay one on top of the other, at least two sheets of carbon cloth, around which an adhesive tape is attached along the contour from them, the surface of the product between the adhesive tape and the sheets carbon fabric is treated with an anti-adhesive composition, then the adhesive tape is removed and in its place at a distance (S) the sealing tape is glued in two rows, inside the contour formed by the sealing tape, a layer of sacrificial material is placed on top of the sheets of carbon fabric; the grids place a binder supply line connected to it, the resulting construction is covered with two layers of a vacuum film, the edges of each of the layers of which are fixed along the entire periphery. each of the assembled vacuum bags is connected via its own vacuum line with a corresponding pump by means of an appropriate sealing bundle, and a vacuum is created in each of these vacuum bags, an epoxy binder is fed and the carbon fabric sheets are impregnated through the binder supply line , the epoxy binder is cured at room temperature for 24 hours, then the vacuum film is removed, the binder feed line The distribution grid and the sacrificial material also carry out post-curing of the product at a temperature of 180 ° C, after which the repaired part of the product is polished in order to obtain an even working surface.

At the same time, in the place of the defect, the damaged part is removed from the product surface by machining, for example, by grinding.

Also during the cleaning of the repaired area, acetone with a degree of purity of analytical grade can be used as a technical low-boiling solvent. or h.ch.

The binder supply line can be made in the form of a spiral polyethylene tube.

And as a sacrificial material can be used perforated film.

The foregoing features and advantages of the invention will be clear from the following description of a preferred exemplary embodiment thereof with reference to the accompanying drawing, which shows a diagram of a part of a polymeric composite product in the course of its repair, in accordance with the present invention and identical positions are used to represent the same elements.

Item 1 of FIG. 1 of a polymer composite material having a defect 2 on its surface needs repair.

Repair of such a product is as follows.

First prepare the surface of the repaired area. To do this, in the place of the defect, the damaged part is removed from the surface of the product for the entire depth of the defect. This operation can be performed by machining, for example, by grinding. The entire repaired area — the polished area of the defect and the area around it — to ensure the greatest adhesion between the repaired area of the product and the repair materials is treated with technical low-boiling solvent, preferably acetone with a degree of purity of chemically pure. or h.d.a.

The treated defect area is covered with at least two sheets of 3 carbon fabrics, laying them on top of one another. The number of carbon cloth sheets depends on the size of the defect, i.e. on how deep it was necessary to remove the damaged part of the product. In this case, the sheets must completely close the treated place of the defect.

Then carry out the impregnation of sheets of carbon fabric epoxy binder. To do this, around the laid sheets of carbon cloth around their perimeter and at a distance from them with the formation of a gap attached adhesive tape. Masking tape can be used as an adhesive tape - a paper tape on a rough basis with an adhesive layer applied on it. The surface of the product between the adhesive tape and the sheets of carbon cloth is treated with an anti-adhesive composition.

Then, the adhesive tape is removed and, in its place, a sealing tape 4 is glued in two rows, forming two contours around one another.

A layer 5 of sacrificial material is placed on top of the carbon cloth sheets inside a contour formed by a sealing cord. Perforated film can be used as a sacrificial material. A distribution grid 6 is placed on top of the sacrificial material, which is connected to the binder supply line 7 located above. Line 7 supply of the binder can be made in the form of a spiral polyethylene tube.

Collect the first and second vacuum bags. To do this, the folded carbon fabric sheets 3 with a layer 5 of sacrificial material and a distribution grid 6 with the binder supply line 7 on top are covered with two layers of vacuum film 8, while the edge of each layer of vacuum film 8 is aligned along its entire perimeter harness 4.

Each of the assembled vacuum bags is connected by means of its vacuum line 9, 10 with a corresponding pump 11, 12, and a vacuum is created in each of said vacuum bags. On line 7 of the binder supply, the epoxy binder is supplied and the sheets 3 are impregnated with carbon fabric.

At the end of the impregnation, the binder supply line 7 is overlapped and the epoxy binder is cured at a room temperature of 25 ± 3 ° C for 24 hours.

After curing the epoxy binder, disassemble the vacuum bags, remove auxiliary materials (layers 9 of the vacuum film, distribution grid 6 with the binder supply line 7 and layer 5 of the sacrificial material) and post cure the product at 180 ° C.

Then the repaired area of the product is polished in order to obtain a smooth working surface.

An example implementation

Equipment 1 of FIG. 1 for the molding of polymer composite materials (PCM), made of polymer composite material, has a defect 2 on its surface. To eliminate the specified defect repair equipment as follows.

First, prepare the surface of the repair section of the tooling. To do this, in the defect area, the damaged part is removed from the tooling surface by grinding over the entire depth of the defect (h). At the same time, a notch is formed on the surface of the tooling. The entire repaired area — the surface of the polished area of the defect and the area around it — to ensure the greatest adhesion between the repaired section of the equipment and repair materials is treated with acetone (according to GOST 2603-79) with a degree of purity of chemically pure. Acetone is the most affordable and effective solvent for the degreasing of the surface, while it quickly evaporates from the treated surface due to its low boiling point. The quality of the surface of a repaired tool depends to a large extent on how well its surface was prepared for repair.

The treated area of defect 2 is covered with two sheets of 3 carbon fabrics, laying them on top of one another. In this case, the carbon fabric sheets 3 completely cover the treated area of the defect 2.

Then around the laid sheets of 3 carbon cloth around their perimeter and at a distance from them with the formation of a gap of at least 50 mm, an adhesive tape is attached. Masking tape can be used as an adhesive tape - a paper tape on a rough basis with an adhesive layer applied on it. The surface of the product between the adhesive tape and the sheets 3 of carbon fabric is treated with an anti-adhesive composition. As the anti-adhesive composition, a release All-brand anti-adhesive liquid is used. At the same time, care should be taken to ensure that the anti-adhesive composition does not fall under sheets 3 of the laid out carbon fabric.

Then the adhesive tape is removed and two rows of sealing tape 4 are glued in its place, forming two contours around one in the other around the repaired area.

Inside the contour formed by two rows of a sealing cord 4, a layer 5 of sacrificial material is placed over the sheets of carbon cloth 3, and perforated film is used as it, because it can be removed more easily from the surface of the repaired area compared to, for example, traditionally used sacrificial fabric, without damage to the preformed materials. A distribution grid 6 is laid out on top of the perforated film. The supply line 7 of the binder in the form of a spiral polyethylene tube is placed on top of the distribution grid 6 in its middle and connected to the distribution grid 6.

Collect the first and second vacuum bags. To do this, laid carbon fabric sheets 3 with perforated film 5 and distribution grid 6 placed on them are covered with two layers of vacuum film 8. And the edge of each layer of vacuum film 8 is combined along its entire perimeter with its corresponding sealing tape 4.

Each of the assembled vacuum bags is connected by means of its vacuum line 9, 10 with a corresponding pump 11, 12, and a vacuum is created in each of said vacuum bags. On line 7 of the binder supply, the epoxy binder is supplied and the sheets 3 are impregnated with carbon fabric.

At the end of the impregnation, the binder supply line 7 is overlapped and the epoxy binder is cured at a room temperature of 25 ± 3 ° C for 24 hours.

At the end of the curing of the epoxy binder, the vacuum bags are disassembled: the auxiliary elements are removed — both layers of the vacuum film 8, distribution grid 6 with the binder supply line 7 and perforated film, which is a layer of sacrificial material 5. Preliminary processing of the surface of the product between the adhesive tape and the sheets 3 carbon fabric anti-adhesive composition has provided an easier removal of the vacuum film 8 from the surface of the snap after carrying out the impregnation and molding of repair materials.

Then carry out the post-curing of the product at a temperature of 180 ° C.

At the end of the repaired area of equipment grind in order to obtain a smooth working surface.

Thus, the proposed method of repairing products from polymer composite materials allows restoring the defective surface of the product without heating the area to be repaired, using simpler equipment for its implementation. At the same time, it provides a more reliable connection of the patch to the repaired area, and the appearance of the repaired area and the mechanical characteristics of the structure in this area correspond to the mechanical characteristics of the intact part of the product, which leads to an increase in the quality of repair.

As an example of the repair of a composite article, a description was given of the repair of a snap for the molding of polymer composite materials made from a polymer composite material. But also the proposed method of repair can be used for the repair of other products, for example, parts of the fuselage of the aircraft, part of the wing system, any other part of the aircraft, etc., made of a polymer composite material. The embodiment described above should be considered in all aspects only as illustrative and not limiting. Consequently, other embodiments of the present invention and implementation examples that are not beyond the essential features described herein may be used.

Claims (20)

1. The method of repairing products from polymer composite materials, characterized in that in the place of the defect, the damaged part is removed from the surface of the product, the repaired area is cleaned with technical low-boiling solvent - acetone with a degree of purity of analytical grade. or h.ch., on top of the defect area lay one on the other at least two sheets of carbon cloth, around which along the contour at a distance from them attach an adhesive tape, the surface of the product between adhesive tape and sheets of carbon cloth is treated with an anti-adhesive composition, then the adhesive tape is removed and in its place a sealing tape is glued in two rows, inside the contour formed by a sealing cord, a layer of sacrificial material is placed over the sheets of carbon cloth, on top of which a distribution grid is placed, a binder supply line connected to it is placed over the distribution grid, the resulting construction is covered with two layers of a vacuum film, the edges of each of the layers of which are fixed along the entire perimeter by means of an appropriate sealing tape with the formation of a corresponding vacuum package, Each of the assembled vacuum bags is connected via its own vacuum line to the corresponding pump, and a vacuum is created in each of the said vacuum bags, along the supply line of the binder, the epoxy binder is supplied and the sheets are impregnated with carbon fabric sheets, the epoxy binder is cured at room temperature for 24 hours, then the vacuum film, the binder supply line, the distribution grid and the sacrificial material are removed and the product is post-cured at a temperature of 180 ° C, then the repaired area of the product is polished in order to obtain a flat working surface. 2. A method according to claim 1, wherein at the defect location, from the surface of the product, the damaged part is removed by machining. 3. A method according to claim 1, wherein at the defect location, from the surface of the product, the damaged part is removed by grinding. 4. A method according to claim 1, wherein during the cleaning of the repaired area, acetone is used as a technical low-boiling solvent with a degree of purity of analytical grade. or h.ch. 5. A method according to claim 1, wherein the supply line of the binder is made in the form of a spiral polyethylene tube. 6. A method according to claim 1, wherein a perforated film is used as a sacrificial material.

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