RU2673238C1 - Manufacturing method of volume thin-walled parts from composite materials - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to the field of mechanical engineering, namely to the manufacture by forming thin-walled parts from composite materials for automotive, shipbuilding, aerospace and other industries, and can be used in the manufacture of bodies of automobile trailers, hulls of boats, yachts, aircraft. Method of manufacturing volumetric thin-walled details from composite materials by the method of contact molding includes cutting out the blanks from the binder impregnated with the binder, laying the blanks on the appropriate configuration of the part of the matrix surface to obtain a package of the required thickness, curing and removing the resulting part from the matrix. For the calculation, a matrix is used, made in the form of a rigid forming frame, lined with metal sheets, mounted on the skeleton on the edges, the anti-adhesive layer and the gel coat layer are applied to the working surface of the metal sheets of the matrix before laying the blanks. After the composite material is laid out and cured, the cured package is removed together with the metal sheets from the matrix scaffold, after which the metal sheets are subsequently separated from the surface of the resulting part.

EFFECT: improved quality of manufacturing of composite materials of large-sized thin-walled parts of complex configuration, as well as with aerodynamic surfaces.

1 cl, 3 dwg

Description

The invention relates to the field of engineering, namely to the manufacture of molding thin-walled parts from composite materials for the automotive, shipbuilding, aerospace and other industries and can be used in the manufacture of bodies of automobile trailers, hulls of boats, yachts, aircraft.

Currently, most large-sized thin-walled parts from composite materials are manufactured by contact molding (see, I.M. Bulanov, V.V. Vorobey. Technology of rocket and aerospace structures from composite materials. - M.: Publishing House of MGTU named after N.E. Bauman, 1998 - pp. 130-135).

During molding, a raw material impregnated with a binder is laid out on the matrix surface and the resulting part is cured.

The matrices used for molding should be made of a material with sufficient rigidity and providing the necessary geometry of the part.

The surface of the matrix should be such that the molded part can be removed without much effort.

A known method of manufacturing a part (spherical plug with a flange for a nozzle of a rocket engine) by contact molding, including cutting blanks from a woven fabric impregnated with a binder, layering blanks on the surface of a steel matrix to the appropriate shell configuration to obtain a package of the required thickness, curing and removing the resulting part from the matrix (RF patent No. 2459105).

Forming on a matrix provides a part whose inner surface reproduces the shape of the outer surface of the matrix.

There is also a known method of manufacturing a part (destructible cover of the launch tube) containing a spherical segment (RF patent No. 2624384).

The part is formed in the response base matrix of a material identical to the material of the shell part.

Forming in the base matrix provides a part whose outer surface accurately reproduces the shape of the inner surface of the matrix.

Using these methods, using simple matrix designs, it is possible to produce sufficiently durable parts with a simple configuration.

For the manufacture of thin-walled parts of complex configuration, it is necessary to use matrices made by special technology.

A matrix (snap) of a polymer composite material equipped with stiffeners can be molded on the surface of a prefabricated master model, which is the prototype of the final product (RF patent No. 2622924).

The matrix (form) for contact forming of parts from layered polymer composite materials can be molded on the surface of a prefabricated reference part (RF patent No. 2309044).

However, the above methods of manufacturing parts by contact molding using these matrix designs do not allow the manufacture of parts with complex surfaces and also with aerodynamic surfaces.

A known method of manufacturing a shell part (air intake of an aircraft) from layered polymer composite materials, in which a matrix (form) with working surfaces is produced by contact molding on a reference air intake, then after removing the matrix, an air intake is formed on its working surfaces (RF patent No. 2351471) , which is the closest analogue of the proposed technical solution.

The known method allows the manufacture of parts with rather complex surfaces, as well as with aerodynamic surfaces.

However, this method is time-consuming and requires significant costs, which is associated with the need for preliminary manufacture of the reference air intake and additional operations to remove the resulting matrix from the reference air intake.

In addition, the processes of extracting the manufactured part from the matrix are difficult, the number of removals of the manufactured parts is limited due to a possible violation of the working surface of the matrix.

The use of a matrix of composite materials leads to reduced maintainability, since local damage to the matrix surface requires expensive repairs.

This method is not technologically advanced and in some cases, the use of the method can lead to insufficiently high surface quality of manufactured large-sized thin-walled parts from composite materials.

The technical problem to which the claimed invention is directed is to increase the manufacturability of the manufacturing process of large-sized thin-walled parts from composite materials by contact molding.

The technical result, which was obtained when solving a technical problem, is to improve the surface quality of large-sized thin-walled parts made of composite materials.

The technical result is achieved by the fact that in the method of manufacturing volumetric thin-walled parts from composite materials by contact molding, including cutting blanks from a woven fabric impregnated with a binder, laying the blanks on the appropriate surface configuration of the matrix to obtain a package of the required thickness, curing and removing the obtained part from the matrix, for calculation use a matrix made in the form of a rigid forming frame, lined with metal sheets, mouth butt-wound on the frame along its edges, while on the working surface of the matrix metal sheets a release layer and a gelcoat layer are applied, the blanks are laid out and cured, then the cured composite material package is removed together with the metal sheets from the matrix frame, after which the metal sheets are sequentially separated from the surface of the resulting part.

The use of a matrix in the manufacture of thin-walled parts made in the form of a rigid forming frame, lined with metal sheets mounted on the butt end-to-end on its edges, eliminates the need for an expensive master model, which in this case is replaced by a designed virtual 3D model on which components are made parts of the surface of the part, followed by a pattern of metal sheets of the matrix, the contour of which corresponds to the contour of the components astkov surface details.

The use of such a matrix design in the proposed method also makes it possible to produce aerodynamically shaped parts with negative angles of the forming surfaces, which is not possible using known matrix designs.

In this case, an analogue of the matrix design proposed for use in the proposed method can be a matrix (molding tool) made of a polymer composite material for contact forming products of volumetric form, which can be made without using a master model or a reference part (see, RF patent No. 2188126) .

The matrix according to this patent is made in the form of a fiberglass forming shell mounted on a fiberglass frame.

In the manufacture of the matrix on a rigid base, a set of ribs from a rigid sheet material is fixed at predetermined intervals, then along the contour of the ribs of the formed frame, workpieces made of rigid sheet material are fixed, from which the forming shell of the matrix is composed.

Part of the blanks are made corresponding to the flat sections of the surface of the shell to be made, another part of the blanks are made corresponding to the mating sections of the flat sections of the shell.

Using the proposed matrix, the working surface of which consists of smooth metal sheets, in comparison with the known matrix, the working surface of which consists of sheets made of composite material, greatly facilitates the process of removing the manufactured parts from the matrix.

Application of a release layer to the working surface of the metal sheets of the matrix before laying the glass fabric blanks makes it easier to separate the metal sheets from the surface of the manufactured part by reducing the adhesion force of the surfaces of the metal sheets and the part after curing the composite material.

The application of gelcoat layers on the adhesive layer previously deposited on metal sheets makes it possible to obtain a glossy colored outer surface of the part and give it a proper presentation after the metal sheets of the matrix are separated from it and eliminate the need for subsequent painting of the part.

Removing the cured part from the composite material together with the metal sheets from the matrix frame ensures guaranteed avoidance of surface damage, both of the manufactured part and of the metal sheets, in the form of scratches, etc. by eliminating the displacement of the metal sheets relative to each other.

The separation of the metal sheets of the matrix from the surface of the obtained part after removing the package of composite material from the matrix frame allows you to completely eliminate the possibility of damage to the surface of the part, since metal sheets from the part can be removed sequentially and with maximum care, avoiding the interaction of the edges of the sheets, as between themselves, and with the surface of the manufactured part.

The essence of the method is illustrated by drawings.

In FIG. 1 shows a matrix-forming matrix framework.

In FIG. 2 shows metal sheets of a matrix.

In FIG. 3 shows the fabricated part.

A method of manufacturing large-sized thin-walled parts from composite materials is as follows.

On a specially made slipway, a rigid form-forming matrix frame is assembled from longitudinal 1 and transverse 2 profiled metal (steel) plates, using the provided groove joints, using corners, plates, and sealant.

The resulting forming frame is lined with metal (steel) sheets 3, which are mounted on the frame end-to-end at their edges, while the sheets 3 are fixed on the frame due to elastic interference (elastic support of the edges of the sheets).

For the manufacture of a set of plates 1,2, and a set of metal sheets 3, the designed virtual 3D model of the part to be manufactured is used, on which a pattern of the constituent parts of the surface of the part is made, followed by the cutting of plates 1,2, metal sheets 3 matrices, dimensions, profile and contour of which correspond to the contour of the constituent parts of the surface of the part.

The assembled structure is a rigid monolithic matrix (shape), including a supporting form-forming frame and a shell for laying out composite material.

On the assembled matrix, the working surface of the metal sheets 3 is prepared for subsequent laying on them of fiberglass blanks.

In this case, degreasing the working surface of the metal sheets 3 of the matrix.

A layer of release compound is applied to a defatted surface.

A gelcoat layer is applied to the release layer deposited on the working surface of the metal sheets 3 of the matrix.

A layer of cold curing binder (epoxy compound) is applied to the gelcoat layer.

From woven material (fiberglass) cut a number of blanks of the desired configuration and size.

Workpieces are laid out in layers, and each laid-out workpiece is impregnated with a binder.

Layering of the blanks is carried out to obtain a package of the required thickness.

Then carry out the curing of the resulting package at room temperature.

Remove the cured part from the composite material together with the metal sheets 3 from the matrix frame.

After that, metal sheets 3 are sequentially separated from the surface of the obtained part 4.

The manufactured thin-walled part is checked for compliance with the required parameters.

The metal sheets 3, after examining the working surface, are again installed on the forming frame for the subsequent operation of the matrix.

The implementation of the method using a matrix made in the form of a rigid forming frame, lined with metal sheets, allows for multiple removal from the matrix of manufactured parts without damage and deformation of the surfaces.

A dramatic increase in the number of part removals is ensured without loss of quality, compared with matrices made of composite materials, since metal is much stronger than plastic.

The proposed method is most suitable for mass production due to the increased number of removals of manufactured parts.

Improved maintainability is provided (in the case of local mechanical damage to the surface of one of the metal sheets, it can simply be replaced with a new one), that is, there is no need for costly repair of the matrix surface, as in the case of using a matrix of composite material.

The present invention improves the manufacturing quality of composite large-sized thin-walled parts of complex configuration, as well as with aerodynamic surfaces.

Claims (1)

A method of manufacturing volumetric thin-walled parts from composite materials by contact molding, including cutting blanks from a woven fabric impregnated with a binder, laying the blanks on the appropriate configuration of the part, the matrix surface to obtain a package of the required thickness, curing and removing the obtained part from the matrix, characterized in that use a matrix made in the form of a rigid forming frame, lined with metal sheets mounted on the frame in a joint along its edges, in this case, a release layer and a gelcoat layer are applied to the working surface of the metal sheets of the matrix, the blanks are laid and cured, then the cured package of composite material is removed together with the metal sheets from the matrix frame, after which the metal sheets are sequentially separated from the surface of the obtained part .

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