WO2021032703A1

WO2021032703A1 - Method and device for producing a component from a fiber composite material

Info

Publication number: WO2021032703A1
Application number: PCT/EP2020/073046
Authority: WO
Inventors: Fabian KÖFFERS; Michael SCHÖLER; Klaus Schürmann; Lothar Sebastian
Original assignee: Siempelkamp Maschinen-Und Anlagenbau Gmbh
Priority date: 2019-08-22
Filing date: 2020-08-18
Publication date: 2021-02-25
Also published as: DE102019005918A1

Abstract

The invention relates to a method for producing an at least partially curved component (1) having a convex outer side from a fiber composite material, said method comprising the steps of: introducing a fiber (1) impregnated with a matrix on an inner mould (7) of a mould space formed between the inner mould (7) and an outer mould (8), introducing a separating membrane (14) on the fiber (1) impregnated with the matrix such that a cavity (15) forms between the outer mould (8) and the separating membrane (14), said cavity extending along the surface (13) of the outer mould (8), wherein the separating membrane (14) has a surface structure on its side facing the fiber (1) impregnated with the matrix, and subjecting the cavity (15) to a thermal oil (17) at a temperature greater than the melting point of the matrix and at a pressure greater than the ambient pressure such that the thermal oil (17) acts with the pressure on the separating membrane (14) in such a manner that a structuring of the outer side of the component (1), which faces the separating membrane (14), is caused by the surface structure of the separating membrane (14). The invention also relates to a device for carrying out the above method.

Description

Method and device for manufacturing a component from a fiber composite material

Technical area

The invention relates to a method for producing an at least partially curved component with a convex outer side from a fiber composite material with the step of introducing a fiber impregnated with a matrix onto an inner shape of a mold space formed between the inner shape and an outer shape. The invention also relates to a device for producing the partially curved component from the fiber composite material with the inner shape on which the fiber impregnated with the matrix is applied.

Background of the invention

Organic sheets belonging to fiber composite materials are known from the prior art and are mainly used in aircraft, ship and automobile construction in order to obtain components that are significantly lighter than conventional materials with comparable or even better rigidity. Such organic sheets generally have a fiber fabric or a fiber lay-up which is embedded in a thermoplastic plastic matrix. Glass, aramid or carbon fibers are often present as fiber materials in the fiber-matrix semi-finished product. Since organic sheets can be easily thermoformed using known metalworking methods, the process times are shorter compared to conventional thermoset fiber composite materials.

As a rule, such organic sheets are used in aircraft, ship or vehicle construction in order to individually prefabricate semicircular fuselage sections made of fiber composite material as lower and upper shells and then to assemble them into a finished component in a subsequent final assembly. The trunk section Ones are often formed by means of an inner shape and an outer shape in a C-frame press, the inner shape and the outer shape being shaped like a cylinder.

The surfaces of the components obtained are naturally exposed to heavy loads due to their use in aircraft, ship or vehicle construction. In the water, the surfaces of ship hulls are colonized by mussels, which generate frictional resistance and thus increase the ship's fuel consumption. Aircraft surfaces have to withstand high temperature fluctuations with accompanying icing. The surface structure of the components therefore not only influences the appearance but also the technical properties, such as driving dynamics, frictional resistance or fuel consumption. The components obtained are thus often provided with lacquers or foils after their production in order to modify the surface structure of the component and, for example, to obtain particularly smooth surfaces. However, such lacquers and foils only have a limited lifespan because the foil or lacquer peel off over time.

Description of the invention

Based on this, it is an object of the present invention to increase the service life of the surface structure. In particular, the object of the invention is to provide a method and a device by means of which a component can be produced in a particularly simple manner from a fiber composite material with a reduced flow resistance and / or a more robust surface structure.

The object of the invention is achieved by the features of the independent claims. Advantageous refinements are given in the subclaims.

Accordingly, the invention relates to a method for producing an at least partially curved component with a convex outer side from a fiber composite material, with the steps of: introducing a fiber impregnated with a matrix onto an inner shape of a mold space formed between the inner shape and an outer shape, a bring a separating membrane onto the fiber impregnated with the matrix in such a way that a cavity extending along the surface of the outer shape is formed between the outer mold and the separating membrane, the separating membrane having a surface structure on its side facing the fiber impregnated with the matrix and subjecting the cavity to a thermal oil at a temperature greater than the melting point of the matrix and at a pressure greater than ambient pressure such that the thermal oil acts with the pressure on the separating membrane in such a way that the surface structure of the Separating membrane structuring of the outer side of the component facing the separating membrane is effected.

In contrast to methods known from the prior art, the structuring of the outside of the component is not applied to the surface of the component as an additional layer, for example, after the component has been molded, but rather is formed during the molding process when the component is manufactured. The structuring of the surface of the component is thus an integral part of the component. The service life of a structuring produced in this way is many times longer than that of a subsequently applied textured paint or a subsequently applied textured film, since the structuring created with the component cannot detach from the component. Furthermore, this method saves a work step, namely the subsequent application of the structuring, as well as additional material, such as, for example, textured paint or textured film. In addition, such a structuring can advantageously change the flow resistance of the outside of the component.

The outside of the at least partially curved component corresponds to the convex surface and / or the outwardly curved surface of the component. For example, in the case of a ship's hull as a component, it is the surface as the outside that comes into contact with water on the finished ship. The structuring of the surface can in principle be generated over the entire surface of the component. Alternatively, only part of the surface can be structured.

In the method according to the invention, the structuring takes place according to the principle of stamping or embossing during the forming process of the component. The structuring produced on the surface of the component thus preferably corresponds to the negative the surface structure of the separating membrane. A depression in the surface structure of the separating membrane preferably leads to an elevation on the surface of the component and vice versa. By choosing the surface structure of the separating membrane, any structuring of the surface of the component can be produced. For example, the component can also be provided with lettering or an identification code in this way.

Structuring within the meaning of the invention means that the surface of the component is not smooth, but rather has a mean roughness value Ra of at least 0.05 mm. There is the possibility that the structuring has such a high average roughness that the structuring is perceived by the eye or haptically by a person. Alternatively, the structuring can have such a low mean roughness value that the surface feels smooth to a person, although the surface has the aforementioned mean roughness value.

In the present forming process, due to the thermal oil, the pressing pressure acts at every point on the separating membrane in the direction of the normal to the separating membrane and thus also in the direction of the normal to the component to be obtained or the fiber soaked with the thermoplastic matrix. Thus, not only a pressing pressure with exclusively vertical components is generated, as is otherwise known from the state of the art presses, for example a C-frame press with a stationary inner shape and an outer shape that can only be moved in the vertical direction. In contrast to a known press, however, the pressing or consolidation pressure required for forming is not or only partially brought about by the press, but instead completely or largely by the thermal oil. In order to create the cavity for the thermal oil, the separating membrane is placed in the outer mold. In particular, it is provided that the separating membrane is placed on the fiber impregnated with the matrix in such a way that the cavity is formed between the outer shape and the separating membrane. The separating membrane serves to separate the thermal oil and the organic sheet on the one hand and to form the cavity for holding the thermal oil on the other. The separating membrane preferably has particularly good heat conduction and pressure transmission. Because the pressure, due to the thermal oil, is at every point on the separating membrane in the direction of the normal to the separating membrane and thus also in the direction of the normal of the component to be obtained acts, the separating membrane can be used as a stamping die in a particularly simple manner in order to produce the structuring of the surface of the component. The proposed method thus makes it possible in a particularly simple manner to produce a component with a structured surface, the structuring being an integral part of the component and therefore very durable.

According to a preferred development, the surface structure has mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures in the micrometer or millimeter range and / or the method includes the step of creating a mushroom-like, honeycomb, groove-like and / or finger-like structure in the micrometer or millimeter range the outside of the component. As already mentioned, the structuring of the separating membrane can in principle be any. However, it is preferably provided that the separating membrane comprises mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures, it being possible for these to be embodied as depressions and / or elevations in the separating membrane. The mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures have dimensions in the range from micrometers to millimeters. This preferably means that an expansion of the surface structure of the separating membrane, that is to say the height or depth of the elevation or depression of the structure, is between 0.05 mm and 5 mm +/- 10%. The height or depth of the elevation or depression of the structure is particularly preferably between 0.5 mm and 500 mm +/- 10%. Since the surface structure is applied to the outside of the component using the principle of stamping or embossing when producing the component, this also corresponds to the expansions of the structuring produced on the outside of the component.

In principle, the surface structure can be produced as a singular elevation or depression on the outside of the component. Preferably, however, it is provided that the surface structure has a regular pattern and / or is designed as a shark skin and / or the method includes the step of generating a structure with a regular pattern and / or as a shark skin on the outside of the component. It is therefore provided in particular that the surface structure not only comprises a single elevation or depression in the surface, but rather comprises a plurality of elevations and / or depressions. These bumps and / or depressions are preferably not distributed randomly over the surface of the component, but rather have a regular arrangement. In particular, it is provided that the structuring has a translation symmetry, that is to say it is a regularly repeating pattern.

It is preferably a honeycomb-like structure, with a hexagonal elevation and / or depression filling the surface in a translationally symmetrical manner. It is also preferably a finger-like or mushroom-like elevation and / or depression, wherein the pattern of the elevations and / or depressions can be described by one of the five two-dimensional Bravais grids. The rack-like or mushroom-like structures form an oblique, a square, a rectangular, a hexagonal or a rectangular face-centered grid. The structuring further preferably comprises fine ribs with sharp points. The outer surface of the component is preferably ribbed in such a way that the structure corresponds to a riblet, also referred to as shark skin. Accordingly, the method preferably includes the step of creating a structure as a shark skin on the outside of the component. The common skin also preferably comprises U-shaped longitudinal grooves. The ribs of the longitudinal grooves are preferably about 10 to 100 mm apart. The height of the ribs is more preferably 10 to 100 mm. The height of the ribs particularly preferably corresponds to the distance between the ribs +/- 20%.

With regard to the structuring, provision is made according to a preferred development that the structuring of the component is designed to reduce frictional resistance, hydrophilicity, hydrophobicity and / or noise emission of the component and / or to increase the stability of the component. In particular, the finger-like and / or mushroom-like structures are suitable for changing the affinity of the surface of the component for water. For example, a water-repellent and / or water-repellent surface (hydrophobic) can be produced. In particular, the surface structure is designed in such a way that a water droplet is essentially spherical on the surface. Furthermore, a contact angle, that is to say the angle that a water drop forms on the surface with respect to this surface, is preferably greater than 120 °. The surface structure is preferably designed in such a way that a lotus effect is achieved. A hydro Phobic structure can, for example, reduce the colonization of a ship's hull with mussels, which can save fuel.

Alternatively, the structuring of the component can be designed to change the hydrophilicity of the surface of the component. The structuring is preferably designed in such a way that the surface of the component is covered with a thin film of water, preferably not visible to the eye, due to the structuring. Furthermore, the contact angle is preferably close to 0 °, in particular 0 ° +/- 20 °.

As a further alternative, the structuring of the component can be designed to advantageously reduce a frictional resistance of the component, or possibly also to increase it. This can be made possible in particular with the riblet structure, also called shark skin. For example, the U-shaped or scale-shaped grooves can influence the frictional resistance, since a laminar flow is preferably generated on the surface. The dimensioning of the riblet structure can be adjusted to the viscosity of the medium, for example air or water, as well as to the expected speed of movement of the aircraft, vehicle or ship.

Furthermore, the structuring can advantageously influence the stability of the component. The stability of the component can be increased in particular with honeycomb-like elevations and / or depressions. The honeycomb-like structures preferably have depressions and / or elevations in the millimeter range, particularly preferably 1 to 3 mm. More preferably, a longitudinal side of the hexagonal honeycomb structure preferably measures between 0.1 and 20 mm.

More preferably, the structure of the surface can reduce the noise emission of the component. A reduction in noise emissions is particularly advantageous for aircraft or rotor blades in wind power plants. The structuring of the surface is preferably designed in such a way that a position of the boundary layer change from a laminar boundary layer to a turbulent boundary layer. Alternatively, the position and the type of structuring on the component can be selected in such a way that the structuring corresponds to a turbulator, which enables the boundary layer flow to become turbulent in a targeted manner. As already mentioned, the structuring on the outside of the component is produced according to the principle of stamping or embossing by means of the surface structure of the separating membrane. In the course of this, it is provided according to a preferred development that the separating membrane is made of metal and that the method includes the step of generating the surface structure of the separating membrane by means of a mechanical and / or a chemical method. All structuring methods known from the processing of metals can be used for simple implementation. For example, it can be provided that the separating membrane is structured with a roller to form the surface structure. Alternatively, it can be provided that the separating membrane is chiseled, punched and / or structured by means of drivers to form the surface structure. More preferably, chemical methods such as etching, electrochemical micro-milling and / or electrochemical removal can be used to maintain the surface structure of the separating membrane.

For the purpose of releasing the finished component after the forming process, the method, according to a preferred development, includes the step of applying, in particular, spraying a release agent onto the inner shape, the outer shape and / or the separating membrane, in particular before introducing the fiber impregnated with the matrix. The separating agent acts as a non-stick layer and, after cooling the fiber impregnated with the matrix, allows the separating membrane, the outer shape and the fiber impregnated with the matrix to be easily detached from one another.

While the method can in principle be carried out with any fiber impregnated with the matrix, the fibers are preferably designed as glass fibers, aramid fibers and / or carbon fibers or carbon fibers. The fiber impregnated with the matrix is very particularly preferably embodied as a fiber-matrix semifinished product, as a fiber composite material and / or as an organic sheet, these terms being used synonymously in the context of the invention. The fiber impregnated with the matrix is preferably embodied as a fiber impregnated with a thermoplastic plastic matrix and / or as glass fiber-reinforced aluminum, also GLARE, as a hybrid material. Fiberglass-reinforced aluminum usually has many, each only a few tenths of a millimeter cke layers which are alternately made of aluminum and a glass fiber laminate, for example glass fiber reinforced plastic.

The fiber can comprise a so-called prepreg material and / or be designed as a tape. The fiber is preferably provided as a continuous material. The matrix can be an epoxy resin or thermoplastic matrix as well as mixtures of the same. For example, the matrix can comprise polyphenylene sulfides, polyaryl ether ketones, or polyether ether ketones as thermoplastics. The temperature is preferably at least 10 ° C., 20 ° C., 50 ° C., 100 ° C. or 200 ° C. greater than the melting point of the matrix. The pressure during the process is preferably at least 10 bar, 20 bar, 30 bar or 40 bar greater than the ambient pressure. The temperature is preferably adapted to the matrix used during the process. More preferably, the fiber is impregnated and / or soaked with the matrix before it is introduced or deposited in the inner mold. In the context of the invention, for example in the description of the figures, the terms fiber impregnated with the thermoplastic matrix and fiber impregnated with the matrix are used synonymously. The prepreg material preferably has a thickness of 180 μm, the carbon fibers contained therein preferably having a thickness between 6 and 9 mm. A cover layer on the outside can be laid in such a way that when the component is subsequently used, the fibers are aligned in the direction of an expected main flow direction. Furthermore, the cover layer can be formed from a different material than at least one other layer of the fiber impregnated with the matrix and / or no fibers, in particular no continuously running carbon fibers. For example, the cover layer can be formed from a high-strength plastic which has a high dimensional stability and no or only a small proportion of reinforcement, for example PEEK. Furthermore, this cover layer can be connected to the layer underneath via an adhesion promoter layer, since there is no risk of delamination of the cover layer, which has a particular influence on the structural strength of the component.

More preferably, the fiber impregnated with the matrix can be configured as a fiber fabric or fabric in which reinforcing fibers are embedded in a plastic matrix. Likewise, a scrim can be provided as a fiber, in particular as a monoaxial or unidirectional scrim, which by fixing a group of parallel len threads can be obtained, as a biaxial scrim, in which two sets of parallel threads are fixed in the direction of two axes, or as a multi-axial scrim, in which several sets of parallel threads are fixed in the direction of different axes. Compared to woven fabrics, non-woven fabrics are characterized by a higher strength due to the elimination of the undulation which is unavoidable in woven fabrics. Furthermore, a plurality of weave types such as plain weave or twill weave can be included in woven fabrics.

According to a preferred development, the matrix of the fiber composite material is made from a thermoplastic, preferably from a polyaryletherketone (PAEK), and / or the fiber in the fiber composite material comprises a mass fraction of at least 50% based on the fiber composite material. Carbon fiber is preferably used as the fiber. This composition has proven to be particularly advantageous for producing the structured surface of the component by means of the method according to the invention.

According to a further preferred development, the curved component has a lower fiber content on its outside than on its inside. This has the particular advantage that the structure of the surface is not influenced by the dimensions or dimensioning of the fibers used. For example, a carbon fiber with a diameter of about 6 mm can be used and nevertheless finger-like structures with a diameter <6 mm can be introduced into the outer surface of the component. For example, the finger-like structures can have a diameter of 3 mm.

With regard to the component to be formed, a preferred development provides that the method is carried out with a press having the inner shape and the outer shape, the inner shape and / or the outer shape being designed to shape an aircraft component, a ship component or a vehicle component. The inner shape and outer shape can basically have any shape, in particular a negative shape of the component to be obtained, as a plane, as a cylinder and / or in cross-section as a semicircle or semicircle, whereby in the following it is often assumed that the inner shape and outer shape are used to manufacture a component of an aircraft , a ship or a vehicle. Furthermore, the component can be a rotor blade of an aircraft or a wind turbine.

In the case of a press, the inner shape can represent the lower tool and the outer shape the upper tool. Even more preferably, the inner shape and outer shape resting on one another close in a pressure-tight and / or sealing manner at their edges and / or are in contact with one another at their edges. In this context, the method preferably has the further step of placing the outer shape on the inner shape in such a way that the outer shape and inner shape lie on one another in a sealing manner at their edges in order to form the mold space and / or fix and / or brace the outer shape and inner shape against one another, especially by means of the press.

According to a preferred development, a press having the inner shape and the outer shape is provided, in particular a C-frame press, and / or the method includes the step, after the separating membrane has been inserted, the inner shape and the outer shape are braced against one another until the Form space is formed, has. The outer shape and the inner shape are preferably designed so that the mold space is pressure-tight after clamping. The press preferably has a press frame, in particular a C-frame, which has an upper horizontal C-leg, a lower horizontal C-leg and a vertical C-base, the upper C-leg and the lower C-leg connects with each other.

The inner form is preferably fixedly supported on the lower horizontal C-leg as a lower tool and the outer form via a press cylinder on the upper C-leg as an upper tool in such a way that the inner form and the outer form can be braced against each other by actuating the press cylinder until the mold space is formed. The C-frame is preferably designed as a frame construction, it being possible to provide several C-shaped press frames connected to one another in the longitudinal direction. The individual press frames are preferably connected to one another with clamping elements. In addition to the above-described upper piston press, in which the press cylinder is supported on the upper C-leg, the press can also be designed in the lower piston design, so that the inner shape through the Press cylinder can be braced against the outer shape provided on the upper C-leg.

According to a further preferred development, the method includes the further step of applying the thermal oil to the cavity at a temperature of ³ 250 ° C, ³ 300 ° C or ³ 400 ° C, such that the thermal oil with the pressure ³ 20 bar, ³ 30 bar or ³ 40 bar acts on the separating membrane and / or, after a predetermined period of time, cooling the thermal oil to a temperature of £ 150 ° C, £ 200 ° C or £ 250 ° C. The cavity is preferably exposed to the thermal oil at a temperature of ³ 300 ° C, ³ 350 ° C, ³ 400 ° C or ³ 500 ° C. The thermal oil acts preferably at a pressure of ³ 30 bar, ³ 40 bar or ³ 50 bar on the separating membrane. The predefined time span can be 1 minute, 10 minutes, 1 hour or 5 hours. When cooling the thermal oil to harden the component, the thermal oil preferably has a temperature of £ 150 ° C or £ 100 ° C. It is very particularly preferred to use the same thermal oil for heating or melting the organic sheet, ie when the cavity is exposed to the thermal oil at a temperature greater than the melting point of the matrix and when the organic sheet is subsequently cooled. In other words, the thermal oil in the cavity is preferably cooled during a pumping process and fed back to the cavity, while the thermal oil continues to act on the separating membrane at a pressure of ³ 20 bar. The pressure and / or temperature curve rise and fall during heating and / or cooling, preferably in parallel.

According to a preferred development, the method includes the step of preheating the outer mold and / or the inner mold to a basic temperature, in particular before the fiber impregnated with the matrix is introduced. For this purpose, heating and / or cooling channels can be provided in the outer shape and / or the inner shape to control the temperature of the respective shape before and / or during curing. The heating channels and / or cooling channels preferably run in the axial direction at regular intervals and / or distributed over the entire outer surface of the respective mold. In order to apply the thermal oil to the cavity, feed channels for the thermal oil are preferably provided which extend in the radial direction through the outer shape. According to an even further preferred embodiment, the method comprises the step of applying a negative pressure to the outer surface of the inner mold. The inner mold is preferably provided with a plurality of negative pressure channels at regular intervals along the lateral surface, which can extend in the radial direction through the lower mold and / or are connected to a vacuum pump by which the negative pressure can be generated. In an analogous manner, a heating and / or cooling device can be provided in order to preheat or cool the outer shape and / or the inner shape to the basic temperature by means of the heating and / or cooling channels.

According to an even further preferred embodiment, the method comprises the step of introducing a stringer, a former and / or a thickening into a recess in the inner mold, in particular before introducing the fiber impregnated with the matrix. Stringers, ribs or thickenings can represent local reinforcements, for example for window, door and / or flap openings in an aircraft, and / or structural reinforcements that can be introduced by the proposed method step when producing the molded part. When the organic sheet is melted by applying the thermal oil to the cavity at a temperature greater than the melting point of the matrix, the connecting contact surfaces of the stringers, frames or thickenings are melted and connected to the organic sheet in this way. The recess is preferably designed in such a way, for example by a milling process, that when the stringer, frame or thickening is inserted into the recess, it is flush with the outer surface of the inner mold. The stringer, the bulkhead or the thickening is preferably used as a prefabricated and consolidated component in the recess.

According to a preferred development, the method comprises the step of cooling the inner mold to a temperature of £ 150 ° C, £ 200 ° C or £ 250 ° C or, after the preceding step, cooling the internal mold to a temperature of £ 150 ° C, £ 200 ° C or £ 250 ° C in the area of the stringer, the frame and / or the thickening. For this purpose, in the area of the stringer, the frame and / or the thickening, a plurality of supply channels extending axially through the inner shape are preferably provided, which are arranged around the recess. In this way it can be ensured that the stringer, frame and / or the thickening provided in the recess are caused by the heated thermal oil Although the remaining part of the stringer melts on the respective connecting contact surface, the frame or the thickened portion remains below a softening temperature.

With regard to further advantages and technical features of the method for producing the at least partially curved component with a convex outside from the fiber composite material, reference is made to the device for producing the partially curved component with a convex outside from the fiber composite, the figures and the further description .

The object of the invention is further achieved by a device for producing an at least partially curved component with a convex outer side from a fiber composite material, with an inner shape on which a fiber impregnated with a matrix is applied, a separating membrane that is attached to the Matrix-impregnated fiber is applied, the separating membrane having a surface structure on its side facing the fiber impregnated with the matrix, an outer shape which rests on the inner shape with the fiber impregnated with the matrix and the separating membrane in such a sealing manner on the inner shape, that a cavity is formed along the surface of the outer mold, and a thermal oil temperature control and pressure device which is designed to act on the cavity with a thermal oil with a temperature greater than the melting point of the matrix and with a pressure greater than the ambient pressure in such a way that the thermal oil with the pressure on the separating membrane acts so that the surface structure of the separating membrane results in a structuring of the outer side of the component facing the separating membrane.

The method for producing the partially curved component from the fiber composite material is preferably carried out with the device described here. The basic idea is that the separating membrane has the surface structure on its side facing the fiber impregnated with the matrix, which is then impressed on the outside of the component, so that the structure is created. The proposed device allows components with a partially curved surface to be produced in a particularly simple manner, the surface of which is structured. For example, components for aircraft, ships or vehicles can be manufactured. The one with the device The surface structuring of the component that is generated is particularly robust and durable, as it is an integral part of the component. The fiber, in particular impregnated with a thermoplastic plastic matrix, is embedded between the inner mold and the outer mold, on the one hand heated by the thermal oil and on the other hand pressurized so that after the subsequent cooling, the structuring of the separating membrane in the surface of the obtained Component. The device can be designed as a press in order to achieve a precise movement, that is to say opening and closing, of the inner shape and outer shape. The inner shape and the outer shape are preferably designed so that, when the press is closed, the shapes are in contact with one another at their edges and thus seal off the mold space formed by the shapes. Likewise, the inner shape and outer shape can be wrapped with tension ropes or otherwise fixed in order to form the mold space.

With regard to the separating membrane, it is provided according to a preferred development that the surface structure has mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures in the micrometer or millimeter range and / or a mushroom-like, honeycomb-like, groove-like and / or finger-like structure in the micrometer range or Millimeter range is effected on the outside of the component. The mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures have dimensions in the range from micrometers to millimeters. This preferably means that an extension of the surface structure of the separating membrane, that is to say the height or depth of the elevation or depression of the structure, is between 0.05 mm and 5 mm +/- 10%. The height or depth of the elevation or depression of the structure is particularly preferably between 0.5 mm and 500 mm +/- 10%.

According to a further preferred development, the surface structure has a regular pattern and / or is designed as a shark skin and / or the impact effects a structuring with a regular pattern and / or as a shark skin on the outside of the component. It is preferably provided that the surface structure not only comprises a single elevation or depression of the surface, but rather comprises a plurality of elevations and / or depressions. These elevations and / or depressions are preferably not randomly across the separating membrane or the outside of the component distributed, but have a regular arrangement. In particular, it is provided that the structuring of the separating membrane has translation symmetry, that is to say that it is a regularly repeating pattern. In this way, a structuring with translational symmetry or a regular repeating pattern is also generated on the outside. It is preferably a honeycomb-like structure, with a hexagonal elevation and / or depression filling the surface in a translationally symmetrical manner. It is more preferably a finger-like or mushroom-like elevation and / or depression, wherein the pattern of the elevations and / or depressions can be described by one of the five two-dimensional Bravais grids. The finger-like or mushroom-like structures of the separating membrane or the outside of the component form an oblique, a square, a rectangular, a hexagonal or a rectangular face-centered grid. The structuring of the separating membrane further preferably comprises hill-like elevations with sharp, pointed depressions. The separating membrane is preferably structured in such a way that the structuring corresponds to an imprint or negative of a riblet.

According to a preferred development, the fiber impregnated with the matrix comprises a preconsolidated semifinished product shell and / or preconsolidated individual layers. The fiber, in particular impregnated with the thermoplastic plastic matrix, can also comprise a fiber fabric and / or a fiber scrim, which are embedded in the thermoplastic plastic matrix. In woven and non-woven fabrics, fibers can run at right angles to one another in order to better define mechanical properties such as rigidity, strength and / or thermal expansion compared to materials known from the prior art, such as sheet metal.

There are basically different possibilities for designing the inner shape and / or the outer shape. According to a particularly preferred development of the method described above and of the device, the inner shape and / or the outer shape are made from Invar. Invar is an iron-nickel alloy with a very low coefficient of thermal expansion, so that an inner shape and / or outer shape designed in this way is characterized by an extremely low expansion due to the temperature change caused by the thermal oil. According to a particularly preferred development, the outside of the component corresponds to a convex surface of the component. The inner shape and / or the outer shape are preferably designed to form a component of an aircraft, ship or vehicle that partially has a curved outer side, this outer side being structured. The outside of this component is preferably the convex surface, that is to say the surface of the component that curves outward. For this purpose, the inner shape and / or the outer shape are preferably designed as a negative shape and the separating membrane also has the negative of the structuring of the surface of the component.

It is also preferred that the cavity between the outer shape and the separating membrane has a thickness of ³ 1 mm and £ 10 mm, in particular ³ 2 mm and £ 5 mm, and / or the cavity at every point on the separating membrane has an equal thickness. In this way it can be achieved that at every point on the fiber impregnated with the matrix an equal or approximately equal pressure is exerted, which is essentially in the direction of the respective normal of the separating membrane, the fiber impregnated with the matrix and / or the outer surface of the inner mold acts. The structuring of the separating membrane is thus stamped particularly precisely on the surface of the component.

Both when the thermal oil is whipped at a temperature greater than the melting point, ³ 250 ° C, ³ 300 ° C or ³ 400 ° C and when the thermal oil is subsequently cooled to £ 150 ° C, £ 200 ° C or £ 250 ° If the pressure is greater than ambient pressure, ³ 20 bar, ³ 30 bar or ³ 40 bar, there is preferably no pressureless phase during the forming process. The fiber especially impregnated with the thermoplastic matrix preferably has a thickness comparable to that of the cavity, so that the thermal oil, due to its significantly higher thermal capacity, is sufficient to bring about the melting process for reshaping the fiber especially impregnated with the thermoplastic matrix. The thermal oil temperature control and pressure device preferably has a heating device, a cooling device and / or a pump in order to heat or cool the thermal oil to the aforementioned temperatures, to pump off the heated thermal oil introduced into the cavity, to cool it and again to be introduced cooled into the cavity, and / or to build up the aforementioned pressure. Brief description of the drawings

The invention is explained in more detail below with reference to the accompanying drawings using a preferred exemplary embodiment.

Show in the drawings

1 shows a device for carrying out the method for producing an at least partially curved component with a convex outer side according to a preferred exemplary embodiment of the invention in a schematic perspective view,

FIG. 2 shows a detail of the device shown in FIG. 1 with an inner shape and

Outer shape in a schematic sectional view, and

3 shows two examples of a surface structure of a separating membrane and one

Structuring of the outside of the partially curved component.

Detailed description of the working examples

1 shows a device in the form of a C-frame press for carrying out a method for producing the at least partially curved component 1 with a convex outside made of organic sheet as a fiber composite material. The C-frame press has a press frame designed as a C-frame 2 with an upper horizontal C-limb 3, a lower horizontal C-limb 4 and a vertical C-base 5, which the upper C-limb 3 and the lower C-limb Leg 4 connects together. The press is designed as a frame construction and has a plurality of press frames 6 which are arranged one behind the other in the longitudinal direction of the press and are each C-shaped and connected to one another. A cylinder-like inner shape 7 is provided, supported on the lower C-leg 4. The inner shape 7 is semicircular in cross section with a cylinder diameter of 6 m. In the longitudinal direction, the inner shape 7 extends between its ends with a cylinder height of 15 m. Above the inner shape 7, an outer shape 8 that is congruent to the inner shape 7, that is, is also cylinder-like, is provided. Thus, through the interaction of the outer shape 8 and the inner shape 7, the component 1 is produced with a convex outer side. Several press cylinders 9 are supported on the upper C-legs 3 and act on the outer shape 8. In this way, the outer mold 8 can be moved in the vertical direction by the press cylinder 9 in the manner of a running beam in order to open or close the mold space between the inner mold 7 and the outer mold 8. In the open state, as shown in FIG 1 to be removed from the device configured in this way, indicated by arrow 10.

With reference to the detail of the inner shape 7 and outer shape 8 lying on top of one another as a schematic sectional view, first in the situation shown in FIG. 1, in which the outer shape 8 is at a distance from the inner shape 7, a separating means 11 is indicated in 2, sprayed onto the inner mold 7. Then a fiber impregnated with a thermoplastic plastic matrix, in particular a glass fiber, aramid fiber and / or carbon fiber, is applied to the inner mold 7 as a preconsolidated semi-finished product shell or in preconsolidated individual layers as what is known as an organic sheet, so that the organic sheet covers the entire surface area 12 of the cylindrical inner shape 7 to to the edges of the inner mold 7 covered. The release agent 11 is sprayed again onto the fiber impregnated with the thermoplastic plastic matrix.

Also in the open state, the separating membrane 14 is applied to the fiber impregnated with the thermoplastic plastic matrix, the separating membrane 14 also covering the entire lateral surface 12 of the inner mold 7. The separating membrane 14 is made of metal, made of stainless steel in the exemplary embodiment described here. The surface of the separating membrane 14 is provided with a surface structure, the structure being present on the side of the separating membrane 14 facing the fiber impregnated with the matrix. The structure of the separating membrane 14 is thus impressed on the outside of the component 1 as a structuring when the component 1 is produced. In the exemplary embodiment described here, the structure corresponds to the separating membrane 14 a negative or an imprint of a riblet structure. The negative of the riblet structure and the riblet structure are shown in FIG. 3a). The outside of the component 1 is embossed as a riblet structure, that is, a shark skin.

The outer surface 13 of the outer mold 8 and the separating membrane 14 form a cavity 15 which extends over the entire outer surface 13 of the outer shape 8 and has an approximately constant thickness between 2 and 5 mm. The inner mold 7 and outer mold 8 are made of Invar iron-nickel alloy and are designed so that when the outer mold 8 rests on the inner mold 7 as shown in FIG. 2 to form the cavity 15, the inner mold 7 and the outer mold 8 at the edges their respective outer surfaces 12, 13 are sealed off or rest on one another in a touching manner.

The device has a thermal oil temperature and pressure device 16, which is designed on the one hand to act on the cavity 15 with a thermal oil 17 at a temperature> 400 ° C, so that a pressure of about 40 bar on the separating membrane 14 due to the thermal oil 17 is exercised. Since the thermal oil 17 can be freely distributed within the cavity 15 along the entire jacket surface 13 of the outer mold 8, the pressure of 40 bar acts at every point on the separating membrane 14 in the direction of the normal of the jacket surface 12 of the inner mold 7 or in the direction of extension of the fiber impregnated with the thermoplastic matrix 1.

The thermal oil 17 thus serves as a pressure and heating medium in order to exert a constant consolidation pressure on the fibers soaked with the thermoplastic matrix on all sides via the separating membrane 14 and for targeted, even heating of the fibers soaked with the thermoplastic matrix 1. The melting process of the fibers soaked with the thermoplastic matrix is brought about by the thermal oil with its fiber 1, which is soaked with the thermoplastic matrix, which is considerably higher than that. After a predetermined period of time, the thermal oil 17 is cooled by the thermal oil temperature control and pressure device 16 to a temperature of <200 ° C. while the pressure remains constant, in order to obtain the component 1. The surface structure of the separating membrane 14 is imprinted on the outside of the component 1 as a structure. Since the structuring of the Production of the component 1 is generated and is thus integratively connected to the component 1, the surface structure of the component 1 is very robust.

FIG. 3 shows a section of the separating membrane 14 and the finished component 1, FIG. 3a) showing the riblet structure or shark skin of component 1 as an example. Due to the riblet structure, the component 1 has a low flow resistance. The Ribelt structure has regularly spaced ribs 24 with sharp points, the points being 50 mm apart in the present exemplary embodiment. The height of the ribs 24, or the depth of the grooves formed by the spaced apart ribs, is 70 mm in each case in the present exemplary embodiment. The riblet structure on the outside of the component 1 is shaped by a structure on the separating membrane 14 which corresponds to a negative of the riblet structure. In Figure 3b) a finger-like structuring of the outside of the component 1 is shown as a further example. This structuring creates a lotus effect, that is to say allows water to roll off the surface of the outside of the component 1. The fingers 25 of the finger-like structure are approximately 100 mm long, 20 mm wide and each 30 mm apart. If the finger-like structures 25 are viewed from above, they are arranged regularly, forming a hexagonal grid.

In order to introduce the thermal oil 17 into the cavity 15, various feed channels 18 are provided in the outer mold 8 which extend radially through the outer mold 8. For heating or cooling, axially extending heating and / or cooling channels 19 are provided in the inner mold 7 as well as in the outer mold 8, whereby a preheating, cooling and / or temperature control of the corresponding mold is possible. By means of a vacuum channel 20 provided in the inner mold 7 and extending radially through the inner mold 7, the jacket surface 12 of the inner mold 7 can be subjected to negative pressure.

Recesses 21 are provided in the inner mold 7, into which, as can be seen from FIG. 2, a stringer 22, on the left, and a cover 23, on the right, are introduced. A plurality of cooling channels 19 are arranged adjacent to the respective cutouts 21, which define the respective cutout 19. During connection contact surfaces of the stringer 22 or the cover 23 melt through the thermal oil 17 and with the the thermoplastic matrix soaked fibers 1 can connect, the arranged around the recess 21 cooling channels 19 serve to cool the stringer 22 or the cover 23 so that they remain below a softening temperature. After the molded part 1 has hardened, as shown in FIG. 1, the outer mold 8 can be lifted and the molded part 1 can be removed from the mold space formed by the inner mold 7 and the outer mold 8. Inner shape 7 and outer shape 8 can be designed to shape a component of an aircraft, vehicle or ship. The exemplary embodiments described are merely examples that can be modified and / or supplemented in many ways within the scope of the claims. Each feature that has been described for a specific exemplary embodiment can be used independently or in combination with other features in any other exemplary embodiment. Each feature that has been described for an exemplary embodiment of a specific category can also be used in a corresponding manner in an exemplary embodiment of another category.

List of reference symbols

Component, fiber impregnated with a matrix 1

C-frame 2 upper C-leg 3

Lower C-leg 4

C base 5

Press frame 6

Inner shape 7 outer shape 8

Press cylinder 9

Arrow 10

Release agent 11

Outer surface (of the inner shape) 12 Outer surface (of the outer shape) 13

Separation membrane 14

Cavity 15

Thermal oil temperature control and pressure device 16

Thermal oil 17 supply channel 18

Heating and / or cooling duct 19

Vacuum channel 20

Recess 21

Stringer 22 thickening 23

Rib 24

Finger 25

Claims

1. A method for producing an at least partially curved component (1) with a convex outer side from a fiber composite material, with the steps: introducing a fiber (1) impregnated with a matrix onto an inner mold (7) one between the inner mold (7) and one Outer shape (8) formed mold space,

Introducing a separating membrane (14) onto the fiber (1) impregnated with the matrix in such a way that a cavity (15) extending along the surface (13) of the outer mold (8) is between the outer mold (8) and the trerm membrane (14). forms, the separating membrane (14) having a surface structure on its side facing the fiber (1) impregnated with the matrix, and

Loading of the cavity (15) with a thermal oil (17) with a temperature greater than the melting point of the matrix and with a pressure greater than the ambient pressure such that the thermal oil (17) acts with the pressure on the separating membrane (14) in such a way that through the surface structure of the separating membrane (14) results in a structuring of the outer side of the component (1) facing the trerm membrane (14).

2. The method according to the preceding claim, wherein the surface structure has mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures in the micrometer or millimeter range and / or with the step

Creation of a mushroom-like, honeycomb-like, scale-like, shark skin-like, groove-like and / or finger-like structure in the micrometer range or millimeter range on the outside of the component (1).

3. The method according to one of the preceding claims, wherein the surface structure has a regular pattern and / or is designed as a shark skin and / or with the step

Generation of a structure with a regular pattern and / or as a shark skin on the outside of the component (1).

4. The method according to any one of the preceding claims, wherein the structuring of the

Component (1) is executed, a frictional resistance, a hydrophilicity, a hydrophobic bie and / or a noise emission of the component (1) and / or to increase the stability of the component (1)

5. The method according to any one of the preceding claims, wherein the separating membrane (14) is made of metal and has the step:

Generating the surface structure of the separating membrane (14) by means of a mechanical and / or a chemical method.

6. The method according to any one of the preceding claims, with the step

Application in particular spraying a release agent (11) onto the inner mold (7), the outer mold (8) and / or the separating membrane (14), in particular before the introduction of the fiber (1) impregnated with the matrix.

7. The method according to any one of the preceding claims, wherein the matrix of the fiber composite material is made from a thermoplastic and / or the fiber (1) in the fiber composite material comprises a mass fraction of at least 50% based on the fiber composite material.

8. The method according to any one of the preceding claims, wherein the curved component (1) has a lower fiber content on its outside than on its inside.

9. The method according to any one of the preceding claims, wherein the inner shape (7) and / or the outer shape (8) is designed to form an aircraft component, a ship component or a vehicle component.

10. Device for producing an at least partially curved component (1) with a convex outer side made of a fiber composite material, with an inner shape (7) on which a fiber (1) impregnated with a matrix is applied, a separating membrane (14), which is applied to the fiber (1) impregnated with the matrix, the separating membrane (14) having a surface structure on its side facing the fiber (1) impregnated with the matrix, an outer mold (8) which rests on the inner mold (7) with the fiber (1) impregnated with the matrix and the separating membrane (14) applied thereon in a sealing manner in such a way that along the surface (13) of the outer mold (8) a Cavity (15) is formed, and a thermal oil temperature control and pressure device (16) which is designed to apply a thermal oil (17) to the cavity (15) with a temperature greater than the melting point of the matrix and with a pressure greater than the ambient pressure, that the thermal oil (17) acts with the pressure on the separating membrane (14), so that the surface structure of the separating membrane (14) effects a structuring of the outer side of the component (1) facing the separating membrane (14),

11. Device according to the preceding device claim, the surface structure having mushroom-like, honeycomb-like, groove-like and / or finger-like surface structures in the micrometer or millimeter range and / or a mushroom-like, honeycomb-like, groove-like and / or finger-like structure due to the impact is effected in the micrometer range or millimeter range on the outside of the component (1).

12. Device according to one of the preceding device claims, wherein the surface structure has a regular pattern and / or is designed as a shark skin and / or a structuring with a regular pattern and / or as a shark skin on the outside of the component (1 ) is effected.

13. Device according to one of the preceding device claims, wherein the fiber (1) impregnated with the matrix comprises a pre-consolidated semifinished product shell and / or pre-consolidated individual layers.

14. Device according to one of the preceding device claims, wherein the inner shape (7) and / or the outer shape (8) is made from Invar

15. Device according to one of the preceding device claims, the outer side of the component (1) corresponding to a convex surface of the component (1).