Apparatus and method for producing molded articles

Abstract

An apparatus (1) for producing molded articles, in particular from fiber composite materials, is shown and described. To ensure uniform pressure and / or temperature application to molded articles, even with more complex geometries, it is proposed that a second press section (P2, P2') is at least partially spaced from the first press section (2) in the direction of the axis of movement (B), and that at least one curvature of the shape of the second press section (P2, P2'), in particular along the longitudinal and / or transverse extension of each press die (2, 3), is at least partially different from at least one curvature of the shape of the first press section (P1, P1'), preferably from the curvature of the shape of the edge region of the first press section (P1, P1') adjacent to the second press section (P2, P2'). Also shown and described are methods for producing molded articles, in particular from fiber composite materials, including the respective apparatus (1) for producing molded articles, in particular from fiber composite materials.

Description

[Technical Field]

[0001] The invention relates to an apparatus for producing molded articles, in particular from fiber composite materials, comprising a first pressing tool (German: Presswerkzeug, English: pressing tool), a second pressing tool and at least one at least partially elastically deformable membrane for contacting a workpiece, the first pressing tool and the second pressing tool being movable relative to one another along a movement axis between an open position and a closed position, wherein at least in the closed position a cavity for a working medium is formed between the membrane and the first pressing tool and / or the second pressing tool and a working space for accommodating a workpiece is formed between the first pressing tool and / or the second pressing tool, the surface of the first pressing tool and / or the surface of the second pressing tool comprising a first pressing section and a second pressing section adjacent to the working space and / or the cavity, and the membrane is made of metal.

[0002] The invention also relates to a method for producing a moulded article, in particular from a fibre composite material, comprising the steps of a) providing a workpiece, b) providing an apparatus for producing a moulded article as claimed in any one of claims 1 to 14, and c) applying pressure and / or temperature to the workpiece by means of the apparatus for producing a moulded article.

[0003] Fiber composites are composite materials that essentially consist of two main components: reinforcing fibers and a plastic ("matrix" or "resin") in which the fibers are embedded. By combining the two main components, it is possible to achieve a composite material with better overall properties than either of the two components alone. For example, the fibers contribute to the tensile strength of the composite due to their high tensile strength in the fiber direction. On the other hand, the matrix ensures that the fibers are held in place and protected from mechanical and chemical influences.

[0004] One of the many options for producing molded articles from fiber composite materials is based on the use of prefabricated intermediate products of fiber and resin (so-called "prepreg," short for "preimpregnated fiber"). In such intermediate products, the fibers contain a resin system that has not yet fully reacted, so that the intermediate product is still provided in a flexible form (e.g., in sheet form, roll). The prepreg is only shaped during the production of the molded article and is cured at high pressure and temperature by completing the chemical reaction. This step can be carried out, for example, in a press.

[0005] Prepregs are processed in large quantities, for example, in the aerospace industry. One processing challenge is that the aerospace industry often requires highly complex part geometries, for example, due to reinforcing components, such as stringers. The goal is also to reduce assembly costs, which can be achieved by using fewer, but larger, parts. The combination of complex geometries and large part dimensions places high demands on the equipment and methods used to produce these parts.

[0006] An apparatus and method for producing molded parts made of fiber composite materials are known, for example, from U.S. Pat. No. 5,623,499. Uniform pressure on the molded part to be produced can be achieved by an elastic membrane acting on the workpiece from which the molded part is to be formed and oil pressure acting on the membrane from the side of the membrane facing away from the workpiece. The membrane is thus pressed against the surface of the workpiece by the oil pressure and thus assumes the shape of the workpiece. This ensures that even curved workpiece or molded part surfaces are subjected to oil pressure on all sides, thereby ensuring that the force acting from the membrane on the workpiece surface is equal at all points, especially the force component acting perpendicular to the workpiece surface. However, one of the drawbacks of U.S. Pat. No. 5,623,499 is that the curvature of the press die shape is constant across the entire surface of the press die. Molded parts with complex geometries, especially those with varying and / or reversing curvatures, cannot be produced with such an apparatus or can be produced only with great difficulty.

[0007] The use of such a "membrane press" for producing molded parts made of fiber composite materials is also known from Patent Document 2. However, one of the drawbacks of Patent Document 2 is that only a rigid wall is provided for contact with the workpiece or molded part. This rigid wall can be connected to a flexible membrane, but this flexible membrane is not intended for contact with the workpiece. In particular, in areas of the workpiece or molded part to be produced that have a less complex geometry, such a rigid wall cannot or does not sufficiently adapt to the geometry of the workpiece or molded part by elastic deformation, making it impossible to apply pressure and / or temperature uniformly. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] German Patent Application Publication No. 10 2017 113 595(A1) [Patent Document 2] U.S. Patent Application Publication No. 2016 / 0297153(A1)

[0009] The present invention is therefore based on the object of providing an apparatus and a method for producing moulded articles, in particular from fibre composite materials, which applies pressure and / or temperature uniformly to moulded articles, even with more complex geometries.

[0010] This object is achieved by an apparatus according to the preamble of claim 1, in which the second press section is at least partially spaced from the first press section in the direction of the axis of movement, and at least one curvature of the shape of the second press section, particularly along the longitudinal and / or lateral extension of each press die, is at least partially different from at least one curvature of the shape of the first press section, preferably the curvature of the shape of the edge region of the first press section adjacent to the second press section. This allows for the geometry of the one or more press dies to be particularly well adapted to workpieces or molded parts having complex geometries. For example, if each press die is intended to contact a workpiece, it is possible to provide one or more press die shapes adapted to this workpiece. This provides uniform contact between the workpiece and the press die, thereby simplifying the uniform application of pressure and / or temperature. For example, if a cavity is formed between each press die comprising the press section and a membrane, it is possible to provide a cavity having a substantially constant thickness, particularly in the closed position. Thus, the shape of each press die can be adapted by the shape of the press section so that the shape of the press section corresponds to the shape of the membrane and / or workpiece, at least when pressure and / or temperature is applied to the workpiece.

[0011] The at least one curvature of the shape of the second press section may differ in particular in amount and / or sign from the at least one curvature of the shape of the first press section, so that the second press section and the first press section extend at least partially in different directions from each other, since the second press section has a change in curvature compared to the first press section.

[0012] The shape of the press sections refers to the general shape of each section. Shape deviations as defined in DIN 4760:1982-06, preferably at least second and / or third and higher order shape deviations, are not considered part of the shape or part of the curvature of the shape. Second order shape deviations are waviness, and third to fifth order shape deviations are roughness. Therefore, the curvature of the shape is not a defect of the press die, in particular of the press sections, in particular a surface defect.

[0013] In particular, at least one curvature of the shape of the second press section is at least partially smaller or larger by at least 1.05 times, preferably at least 1.25 times, more preferably at least 2 times, more preferably at least 4 times, more preferably at least 10 times, more preferably at least 25 times, more preferably at least 50 times, more preferably at least 100 times, more preferably at least 250 times, more preferably at least 500 times, more preferably at least 1000 times, more preferably at least 2500 times, more preferably at least 5000 times, in particular at least 10000 times.

[0014] The apparatus includes a first, preferably upper, press die and a second, preferably lower, press die, although the apparatus may include additional press dies. The first and / or second press dies may be designed as a single unit or as an assembly. The first and / or second press dies are preferably made of metal, particularly nickel-rich steel, nickel-rich cast iron, or nickel-rich cast steel. The nickel content of each may be greater than 34%, preferably between 35.7% and 36.7% or between 40.8% and 43.6%. The use of metal, particularly steel, allows for a long press die life. In the case of steel, for example, Invar 36, this steel also has an extremely low thermal expansion coefficient. Therefore, the use of Invar allows for extremely precise production of molded parts, even when temperatures change during the pressing process. An even greater advantage can be achieved by using specially adapted casting alloys, preferably nickel-rich cast iron or nickel-rich cast steel, which not only maintain a low maximum coefficient of thermal expansion throughout most of the heating and cooling process in the press cycle, but also match the requirements of the workpiece material, e.g., a (glass or carbon fiber reinforced) thermosetting material or a (glass or carbon fiber reinforced) thermoplastic material. Furthermore, the use of casting materials offers considerable economic advantages, since high-nickel alloy steels are very expensive and the reduction ratios in mold making are still often well above 50%, and usually even above 70% or 80%.

[0015] The first and second press dies are movable relative to each other along a movement axis between an open position and a closed position. This allows the press dies to be moved toward and away from a workpiece inserted into the press or a molded part produced from the workpiece. In the open position, a workpiece can be inserted between the press dies or a completed molded part can be removed between the two press dies. In the closed position, additional pressure and / or temperature can be applied to the workpiece, resulting in a molded part being produced from the workpiece. The defined movement of the press dies is determined by a movement axis. This movement axis is an axis along which the press dies are moved relative to each other between the open and closed positions. Advantageously, the movement axis extends horizontally or vertically. Alternatively or additionally, the movement axis extends through the first and / or second press dies, particularly substantially through the centers of the first and / or second press dies. Alternatively or additionally, the movement axis may extend through the working space and / or cavity, in particular substantially through the center of the working space and / or cavity. Furthermore, the movement axis may extend from the first press die to the second press die or vice versa. Furthermore, the movement axis may extend parallel to the height axis of the first press die and / or the second press die, in particular the height axis of the apparatus.

[0016] The first pressing die and / or the second pressing die may advantageously have an at least partially constant thickness, at least adjacent the working space and / or cavity, in particular in the direction of the movement axis.

[0017] The apparatus also includes at least one at least partially elastically deformable membrane for contacting the workpiece. The at least partially elastically deformable membrane allows the membrane to be adapted to the geometry of the workpiece or the part to be produced. The membrane may advantageously be at least partially linearly elastically deformable. Advantageously, a membrane is also provided for contacting the part to be produced and / or for applying pressure and / or temperature to the workpiece. The membrane is advantageously at least partially movable, preferably deformable, more preferably elastically deformable, particularly linearly elastically deformable, in the direction of the working space, the cavity, the first press die, and / or the second press die. The membrane may also be substantially completely elastically deformable, particularly linearly elastically deformable. However, in the case of complex geometries of the workpiece or the part to be produced, it is advantageous if a portion of the membrane is plastically pre-deformed and thus already adapted to the shape of the workpiece or the part to be produced prior to exposing the workpiece to pressure and / or temperature.

[0018] In this case, the membrane is also made of metal. This provides a sufficiently stable membrane capable of withstanding high pressures and / or temperatures, and the membrane itself has high thermal conductivity. Furthermore, the metallic membrane may be elastically and plastically deformed, particularly pre-plastically deformed. A special feature of this device is the use of a metallic membrane in combination with a first press section and a second press section, where the second press section is at least partially spaced from the first press section in the direction of the movement axis, and at least one curvature of the shape of the second press section is at least partially different from at least one curvature of the shape of the first press section, preferably the curvature of the shape of the edge region of the first press section adjacent to the second press section. For press dies and / or workpieces with such complex geometries, metallic membranes may be used only to a limited extent or not at all. Metal membranes may be elastically deformable to some extent. However, compared to membranes made of other materials, such as silicone, their elastic deformability, especially linear elastic deformability, is significantly lower. Therefore, metallic membranes can only adapt to the geometry of the press die and / or workpiece through elastic deformation to a certain extent. However, this drawback can be compensated for, for example, by pre-plastically deforming the membrane's molded section. One advantage of metallic membranes over silicone membranes is that they can withstand higher pressures and / or temperatures than silicone membranes.

[0019] The membrane is preferably formed as a single member and / or integrally, in particular made from a single sheet metal. Advantageously, the membrane thickness is at least 0.05 mm, preferably at least 0.2 mm, in particular at least 0.25 mm. This ensures sufficient strength of the membrane. Alternatively or additionally, the membrane thickness is at most 4 mm, preferably at most 2 mm, in particular at most 1.5 mm. This ensures sufficient flexibility of the membrane.

[0020] The membrane may preferably be made of steel, in particular stainless steel. In simple cases, it may be sufficient to use stainless steel according to material specification 1.4301 to produce the membrane. However, it is preferable to use steel, in particular stainless steel, with good to excellent deep-drawing properties, i.e., so-called deep-drawing steel, to produce the membrane.

[0021] The membrane may advantageously have a tensile strength of 300 to 850 MPa, in particular 310 to 540 MPa or 490 to 830 MPa. - carbon in the range of approximately 0.16% to 0.22%; - silicon up to about 0.13%; - manganese in the range of approximately 0.2% to 0.4%; - up to approximately 0.25% nickel, - maximum of approximately 0.025% sulfur, - up to approximately 0.025% phosphorus, - maximum of approximately 0.15% chromium, - Aluminum in the range of approximately 0.02% to 0.07%; - maximum of approximately 0.2% copper, Iron and unavoidable impurities, residues For example, the membrane may be made from hot-annealed or hot-rolled steel strip according to GOST 2284-79.

[0022] Other steel alloys containing chromium, nickel and, advantageously, titanium and / or copper can also achieve good results.

[0023] The membrane is preferably at least partially disposed between the first press die and the second press die. Furthermore, the first press die and / or the second press die may be connected to the membrane. The apparatus may include two or at least two membranes. The use of two or at least two membranes allows for easy transfer of pressure and / or temperature to the workpiece from different sides.

[0024] A cavity for the working medium is formed between the membrane and the first and / or second press die, at least in the closed position. This cavity may be formed between the membrane and the first and / or second press die in both the open and closed positions, preferably in each of the press dies. The cavity is preferably at least partially defined by the membrane and the first and / or second press die. The cavity advantageously has a substantially equal thickness at substantially every point between the membrane and the first and / or second press die, particularly along the longitudinal and / or lateral extension of the membrane. In other words, the cavity has a substantially constant thickness, at least in the closed position. The cavity may be filled with a working medium, which may be, for example, a gas or a liquid. Pressure and / or temperature may preferably be applied to the working medium. The pressure and / or temperature applied to the working medium may be transmitted to the workpiece by the membrane. The cavity may advantageously be expandable in the direction of the working space. An oil pressure of at least 0.1 bar, preferably at least 2 bar, more preferably at least 6 bar, in particular at least 8 bar and / or at most 40 bar, preferably at most 26 bar, in particular at most 22 bar may be applied to the cavity, which may preferably be sealed by the first and / or second pressing dies and the membrane against an oil pressure of at least 4 bar, advantageously at least 8 bar, in particular at least 40 bar.

[0025] A working space for accommodating a workpiece is also formed between the first and second press dies, in particular between the membrane and the first and / or second press dies. This working space is preferably formed at least in an open position and / or at least in a closed position, in particular in each of the press dies. In this case, the workpiece can be introduced into the working space in the open position, and pressure and / or temperature can be applied to the workpiece in the closed position, in particular by the membrane.

[0026] The surface of the first press die and / or the surface of the second press die may have a first press section and a second press section. Thus, both the surface of the first press die and the surface of the second press die may have a first press section and a second press section. However, the surface of the first press die and / or the surface of the second press die may have further press sections. The first press section and the second press section are preferably also adjacent to each other, particularly along the longitudinal and / or lateral extension of each press die.

[0027] The first and second press sections are adjacent to the work space and / or cavity. The press sections thus form sections of a press die intended for contacting the workpiece and / or forming the shape of the cavity. In particular, the first and second press sections are adjacent to the work space and / or cavity at least in the closed position, preferably at least in the closed and open positions. Furthermore, preferably, the first and / or second press sections are at least partially, preferably substantially completely, oriented toward the work space and / or cavity, in particular at least in the closed position.

[0028] The first and / or second press sections are preferably also designed to contact the workpiece. Thus, each press section forms a contact surface for the workpiece. Due to the design of the press sections, the press die is also suitable for holding workpieces with complex geometries. The first and / or second press sections may extend at least partially, preferably substantially completely, straight, and / or may extend at least partially, preferably substantially completely, curved.

[0029] The longitudinal extension of each press die refers in particular to the extent of each press die along its longitudinal axis, starting from a lateral side of the press die. The lateral extension of each press die refers in particular to the extent of each press die along its lateral axis, starting from a longitudinal side of the press die. The lateral extension of each press die does not have to extend exclusively or at least partially in the direction of the lateral axis of the press die. For example, if each press die extends at least partially in the shape of a circle around the longitudinal axis of the press die, the lateral extension of each press die extends proportionally in the direction of the lateral axis of the press die and proportionally in the direction of the height axis of the press die. This also applies correspondingly to the longitudinal extension of each press die. The longitudinal axis of each press die and the lateral axis of each press die are perpendicular to each other.

[0030] A first embodiment of the apparatus is characterized in that the second press section is at least partially spaced apart from the first press section in the direction of the axis of movement by a distance of at least 5 mm, preferably at least 50 mm, more preferably at least 150 mm, even more preferably at least 200 mm, even more preferably at least 300 mm, even more preferably at least 500 mm, and particularly at least 1000 mm. Suitable spacing can simplify the uniform application of pressure and / or temperature to workpieces with complex geometries, since the press section can better adapt to the geometry of such workpieces or provide cavities with more uniform thicknesses when applying at least pressure and / or temperature to the workpieces. Alternatively or additionally, the distance can be at least 1.25 times, preferably at least 1.41 times, more preferably at least 7 times, even more preferably at least 25 times, even more preferably at least 50 times, and particularly at least 100 times the thickness of the film.

[0031] According to one embodiment of the apparatus, at least one curvature of the shape of the second press section, particularly along the longitudinal and / or transverse extension of each press die, is designed at least partially opposite to at least one curvature of the shape of the first press section, preferably the curvature of the shape of the edge region of the first press section adjacent to the second press section. This provides a press die shape that is adapted to the geometry of the workpiece or molded part to be produced. Therefore, when at least pressure and / or temperature are applied to the workpiece, the press sections can contact the workpiece more uniformly or provide a cavity with a more uniform thickness. In this case, opposite curvature means that the curvatures have mutually different signs. For example, the first press section may be curved to the left and therefore have a positive sign, while the second press section may be curved to the right and therefore have a negative sign or no curvature at all. In this case, the curvature is zero, i.e., the curvature has no sign. A positive sign, a negative sign, and no sign can be considered as different signs.

[0032] A further embodiment of the apparatus is characterized in that the second press section extends at least partially obliquely relative to the first press section, particularly along the longitudinal and / or transverse extension of the respective press dies, and preferably there is an angle of at least 90°, preferably at least 100°, in particular at least 120°, and / or an angle of at most 180°, preferably at most 160°, in particular at most 145°, between the first and second press sections at least partially. This provides a shape of the press die that can be adapted to the geometry of the workpiece or the molded part to be produced. Thus, the press section can contact the workpiece more uniformly or provide a cavity with a more uniform thickness, at least when pressure and / or temperature are applied to the workpiece.

[0033] According to a further embodiment of the apparatus, the surface of the first press die and / or the surface of the second press die include a third press section, preferably at least partially spaced apart from the first press section and / or the second press section in the direction of the axis of movement, preferably at least partially spaced apart from the first press section and / or the second press section in the direction of the axis of movement by a distance of at least 5 mm, preferably at least 50 mm, more preferably at least 150 mm, even more preferably at least 200 mm, even more preferably at least 300 mm, even more preferably at least 500 mm, and in particular at least 1000 mm. The provision of a third press section allows the shape of the press die to be adapted more incrementally, thereby allowing for a better fit to the geometry of complex components. The appropriate spacing simplifies the uniform application of pressure and / or temperature to workpieces with complex geometries. This is because, when applying at least pressure and / or temperature to the workpiece, the press section can provide a cavity that is better adapted to the geometry of such a workpiece or has a more uniform thickness. Alternatively or additionally, the distance may be at least 1.25 times, preferably at least 1.41 times, more preferably at least 7 times, even more preferably at least 25 times, even more preferably at least 50 times, and particularly at least 100 times the thickness of the film. The third press section is adjacent to the working space and / or cavity. The third press section is preferably also adjacent to the second press section. It may be advantageously provided that the third press section is at least partially, preferably substantially completely, oriented toward the working space and / or cavity, especially at least in the closed position. The third press section may be designed to contact the workpiece. Thus, the third press section forms a contact surface for the workpiece.The third press section may extend at least partially, preferably substantially completely straight, and / or may extend at least partially, preferably substantially completely curved.

[0034] Alternatively or additionally, the first press section, the second press section and / or the third press section may have a length, in particular along the longitudinal and / or lateral extension of the respective press die, of at least 6 mm, preferably at least 50 mm, more preferably at least 70 mm, even more preferably at least 100 mm, even more preferably at least 150 mm, even more preferably at least 500 mm, in particular at least 1000 mm.

[0035] A further embodiment of the apparatus provides that at least one curvature of the shape of the third press section, particularly along the longitudinal and / or lateral extension of each press die, is at least partially different from at least one curvature of the shape of the first press section and / or at least one curvature of the shape of the third press section is at least partially different from at least one curvature of the shape of the second press section, preferably at least partially different from the curvature of the shape of the edge region of the second press section adjacent to the third press section. This provides a shape of the press die that is adapted to the geometry of the workpiece or the molded part to be produced. Thus, when at least pressure and / or temperature are applied to the workpiece, the press sections can contact the workpiece more uniformly or provide a cavity with a more uniform thickness. This applies particularly to workpieces that have curved surfaces and / or surfaces that extend at an angle to each other adjacent to the press sections. At least one curvature of the shape of the third press section may differ from at least one curvature of the shape of the first press section and / or the second press section, in particular with respect to the amount and / or sign, so that the third press section and the second press section and / or the first press section extend at least partially in different directions, respectively, since the third press section has a change in curvature relative to the first press section and / or the second press section.Advantageously, at least one curvature of the shape of the third press section is at least partially smaller or larger by at least 1.05 times, preferably at least 1.25 times, more preferably at least 2 times, more preferably at least 4 times, more preferably at least 10 times, more preferably at least 25 times, more preferably at least 50 times, more preferably at least 100 times, more preferably at least 250 times, more preferably at least 500 times, more preferably at least 1000 times, more preferably at least 2500 times, more preferably at least 5000 times, in particular at least 10000 times, at least 2500 times, more preferably at least 5000 times, in particular at least 10000 times.

[0036] It may also be provided that the third press section and the first press section and / or the second press section have substantially the same curvature and / or extend substantially parallel to one another.

[0037] According to a further embodiment of the apparatus, at least one curvature of the shape of the third press section, particularly along the longitudinal and / or transverse extension of each press die, is designed at least partially opposite to at least one curvature of the shape of the first press section and / or at least one curvature of the shape of the third press section, particularly along the longitudinal and / or transverse extension of each press die, is designed at least partially opposite to at least one curvature of the shape of the second press section, preferably the curvature of the shape of the edge region of the second press section adjacent to the third press section. This provides a shape of the press die that can be adapted to the geometry of the workpiece or the molded part to be produced. Therefore, the press sections can contact the workpiece more uniformly or provide cavities with a more uniform thickness when at least pressure and / or temperature are applied to the workpiece.

[0038] A further embodiment of the apparatus is characterized in that the third press section extends at least partially obliquely relative to the first and / or second press sections, particularly along the longitudinal and / or transverse extension of the respective press dies, preferably at least partially at an angle of at least 90°, preferably at least 100°, in particular at least 120°, and / or at most 180°, preferably at most 160°, in particular at most 145°, between the third press section and the first and / or second press sections. This provides a shape of the press die that can be adapted to the geometry of the workpiece or the molded part to be produced. This allows the press sections to contact the workpiece more uniformly or to provide a cavity with a more uniform thickness, at least when pressure and / or temperature are applied to the workpiece.

[0039] Further embodiments of the apparatus provide that the first, second, and / or third press sections, in particular the shape of the first, second, and / or third press sections, are at least partially curved about the longitudinal axis of the apparatus or an axis parallel to the longitudinal axis, about the transverse axis of the apparatus or an axis parallel to the transverse axis, and / or about the height axis of the apparatus or an axis parallel to the height axis. This makes it possible to produce press dies with complex geometries. Thus, the press sections can contact the workpiece more uniformly or produce cavities with more uniform thicknesses, at least when pressure and / or temperature are applied to the workpiece. This is particularly true for workpieces or molded parts to be produced that have complex geometries. Preferably, the first, second, and / or third press section, particularly the shape of the first, second, and / or third press section, is at least partially curved about at least two of the following axes: the longitudinal axis of the device or an axis parallel to the longitudinal axis of the device; the transverse axis of the device or an axis parallel to the transverse axis of the device; and the height axis of the device or an axis parallel to the height axis of the device. In other words, the first, second, and / or third press section, particularly the shape of the first, second, and / or third press section, is advantageously at least partially curved about at least two axes extending perpendicular to each other. This provides an at least partially doubly curved press mold, which facilitates the production of molded parts with complex geometries, particularly doubly curved parts, or the provision of cavities with more uniform thicknesses, even in the case of molded parts with complex geometries.

[0040] The longitudinal axis of the device and the lateral axis of the device are perpendicular to each other. The height axis is also perpendicular to the longitudinal axis of the device and the lateral axis of the device. Each axis of the device is an axis of the device for producing a molded article.

[0041] According to a further embodiment of the device, it is provided that the membrane has at least one elastically deformable base section for contacting the workpiece, particularly along the longitudinal and / or lateral extension of the membrane, and at least one pre-plastically deformed shaping section for contacting the workpiece, preferably pre-plastically deformed relative to the base section, particularly along the longitudinal and / or lateral extension of the membrane, at least in the open position. The combination of an elastically deformable base section that can very well elastically adapt to the relatively uncomplicated geometry of the workpiece or the part to be produced therefrom, prior to applying pressure and / or temperature to the workpiece, with a pre-plastically deformed shaping section that has already been adapted to the complex geometry of the workpiece or the part to be produced therefrom by pre-plastic deformation, allows for particularly uniform exposure of complexly changing geometries to pressure and / or temperature.

[0042] The longitudinal extension of the membrane refers in particular to the extent of the membrane along its longitudinal axis, starting from a lateral side of the membrane. The lateral extension of the membrane refers in particular to the extent of the membrane along its lateral axis, starting from a longitudinal side of the membrane. The lateral extension of the membrane does not have to extend exclusively or at least partially in the direction of the lateral axis. For example, if the membrane extends at least partially in an arc about the longitudinal axis of the membrane, the lateral extension of the membrane extends proportionately in the direction of the lateral axis of the membrane and proportionately in the direction of the height axis of the membrane. The same applies to the longitudinal extension of the membrane. The height axis of the membrane is an axis that is perpendicular to the longitudinal axis of the membrane and the lateral axis of the membrane. The longitudinal axis of the membrane and the lateral axis of the membrane are also perpendicular to each other.

[0043] The membrane may advantageously comprise at least two base sections, in particular a plurality of base sections, and / or at least two forming sections, in particular a plurality of forming sections. The base sections are elastically deformable, in particular linearly elastically deformable, and therefore can very well adapt to the shape of the workpiece or molded part to be produced. In contrast, the forming sections are pre-plastically deformed. This means that the shape is imprinted on the forming sections by plastic deformation, in particular relative to the base sections. The forming sections are also plastically deformed relative to the base sections as a result of the pre-plastic deformation. The pre-plastic deformation is carried out beyond the elastic limit of the membrane material. The pre-plastic deformation preferably produces plastic deformation at least on the side of the forming section adjacent to the cavity and / or at least on the side of the forming section adjacent to the working space, in particular over substantially the entire membrane thickness of the forming sections. The shape of the forming sections, in particular imprinted by the pre-plastic deformation, advantageously differs from the basic shape of the membrane, in particular the basic shape of the base sections, at least in the open position of the press mold, in particular in the unloaded state of the membrane. The purpose of pre-plastic deformation is to at least partially adapt the shaping section to the shape of the workpiece or the shaped article to be produced from the workpiece by the apparatus. Pre-plastic deformation may be used to impart a shape to the shaping section that cannot be achieved by elastic deformation, especially linear elastic deformation, of the membrane during the production of the shaped article. Thus, pre-plastic deformation of the shaping section results in a controlled adaptation of the shape of the shaping section and thus the shape of the membrane, instead of uncontrolled plastic deformation of the membrane when pressure and / or temperature are applied. Uncontrolled plastic deformation of the membrane could result in damage to the membrane. The shaping section does not need to be completely pre-plastically deformed; preferably, it is sufficient for the shaping section to be at least partially pre-plastically deformed, and preferably, it is pre-plastically deformed to a large extent. However, it may be advantageous for the shaping section to be substantially completely pre-plastically deformed.

[0044] Pre-plastic deformation of the shaping section does not mean, for example, the general plastic deformation of the entire starting material used for the membrane, for example in a rolling mill, or the plastic deformation that the membrane may undergo when applying pressure and / or temperature during the production of a shaped article. The shaping section is advantageously pre-plastically deformed, in particular relative to the base section, at least on the side of the shaping section adjacent to the cavity and / or at least on the side of the shaping section adjacent to the working space.

[0045] The use of a metallic membrane with a pre-plastically deformed section makes it possible to produce molded parts with complex geometries under high pressures and / or temperatures, which is not possible with non-metallic membranes, such as silicone membranes. Silicone membranes, for example, can better conform to the complex geometries of the workpiece or molded part to be produced, but they can only withstand lower pressures and / or temperatures than metallic membranes. For example, the disadvantage of metal membranes, such as their lower flexibility compared to silicone membranes, is compensated for in this case by the pre-plastically deformed mold section, which is adapted to the section of the workpiece or molded part to be produced with complex geometries. Preferably, both the mold section and the base section are made from the same metal. It may also be provided that the base section and the mold section are integrally formed with each other, in particular, made from a single sheet.

[0046] It may further be proposed that the shape of the second press section corresponds to the shape of the forming section, in particular the shape of the surface of the forming section on the side adjacent to the cavity and / or the shape of the side of the forming section adjacent to the working space, and / or that the shape of the first press section and / or the third press section at least partially corresponds to the shape of the base section, in particular the shape of the surface of the base section on the side adjacent to the cavity and / or the shape of the side of the base section adjacent to the working space.

[0047] The base section and the shaped section of the membrane are arranged in particular along the longitudinal and / or transverse extension of the membrane. The base section and the shaped section advantageously extend along the longitudinal and / or transverse extension of the membrane. Preferably, the base section and the shaped section are adjacent to each other in particular along the longitudinal and / or transverse extension of the membrane.

[0048] It may also be provided that, at least in the open position, the shaping section and / or the base section, in particular the shape of the shaping section and / or the shape of the base section, is at least partially curved about the longitudinal axis of the membrane or an axis parallel to the longitudinal axis of the membrane, about the transverse axis of the membrane or an axis parallel to the transverse axis of the membrane, and / or about the height axis of the membrane or an axis parallel to the height axis of the membrane. This facilitates the production of shaped articles with complex geometries. In the case of the shaping section, this curvature is imprinted on the shaping section by pre-plastic deformation. Preferably, it is provided that, at least in the open position, the shaping section and / or the base section, in particular the shape of the shaping section and / or the shape of the base section, is at least partially curved about at least two of the following axes: the longitudinal axis of the membrane or an axis parallel to the longitudinal axis of the membrane, the transverse axis of the membrane or an axis parallel to the transverse axis of the membrane, and the height axis of the membrane or an axis parallel to the height axis of the membrane. In other words, it is advantageous if, at least in the open position, the shaping section and / or the base section, in particular the shape of the shaping section and / or the shape of the base section, are at least partially curved about at least two axes extending perpendicular to one another. This provides an at least partially doubly curved membrane. This makes it easier to produce shaped articles with complex geometries, in particular doubly curved. It is advantageously provided that the shaping section, preferably the shape of the shaping section, is at least partially curved about at least two axes extending perpendicular to one another, preferably by pre-plastic deformation of the shaping section relative to the base section.

[0049] Furthermore, it may be provided that, at least in the open position, the molding section is at least partially spaced from the base section, particularly the edge region of the base section adjacent to the molding section, in the direction of the cavity and / or the direction of the working space, particularly substantially perpendicular to the surface of the edge region of the base section adjacent to the molding section, with the spacing being at least equal to the thickness of the film. This provides a molding section that can be adapted to the complex geometry of the workpiece or molded part to be produced. In particular, the molding section provides sufficient space for the protrusion of the workpiece or molded part to be produced from the workpiece, even when already in the open position and while pressure and / or temperature are being applied to the workpiece. Furthermore, the molding section designed in this way may be positioned sufficiently close to the recess of the workpiece or molded part to be produced, thereby achieving uniform contact of the molding section. For example, a distance in the direction of the cavity may result in a larger cavity volume. This is because, to achieve a sufficient distance between the molding section and the press die, the distance between the membrane and the press die is generally increased throughout. This results in higher acquisition costs, higher operating costs, a higher risk of leakage, and increased sluggishness in temperature control, but has the advantage that, when considering the same overall process, at least a similar degree of uniformity in the pressure distribution acting in the pressing process is achieved in the molding section. Advantageously, at least in the open position, a distance exists between the side of the molding section adjacent to the cavity and the side of the base section adjacent to the cavity and / or between the side of the molding section adjacent to the working space and the side of the base section adjacent to the working space. Advantageously, the distance may be at least 6 mm, preferably at least 15 mm, more preferably at least 50 mm, in particular at least 72 mm, and even more preferably at least 1000 mm. Alternatively or additionally, the distance may be at least 1.25 times the membrane thickness, preferably at least 1.41 times, more preferably at least 7 times, more preferably at least 25 times, more preferably at least 50 times, especially at least 100 times.Advantageously, the shaping section may be spaced a predetermined distance from the base section in the direction of the height axis. It may also be provided that the film thickness of the shaping section differs from that of the base section, in particular from that of the edge region of the base section adjacent to the shaping section, by at most 40%, preferably at most 25%, more preferably at most 15%, particularly at most 10%, and even more particularly at most 5%. This provides a film with a particularly uniform film thickness. In this case, the pre-plastic deformation of the shaping section only slightly affects the film thickness of the shaping section. The film thickness deviation is advantageously present substantially along the entire shaping section. Advantageously, both the shaping section and the base section, in particular the edge region of the base section adjacent to the shaping section, have substantially the same film thickness.

[0050] It may be provided that the forming section extends, in particular along the longitudinal and / or transverse extension of the membrane, by at least 6 mm, preferably at least 50 mm, more preferably at least 70 mm, even more preferably at least 100 mm, even more preferably at least 150 mm, even more preferably at least 500 mm, in particular at least 1000 mm, thereby providing a sufficiently large forming section, which is also suitable for workpieces or parts to be produced with larger dimensions and complex geometries.

[0051] A further embodiment of the device is characterized in that, at least in the open position, the curvature of the shape of the forming section, particularly along the longitudinal and / or lateral extension of the membrane, differs at least partially from the curvature of at least one shape of the base section, preferably from the curvature of the shape of the edge region of the base section adjacent to the forming section. This provides a pre-deformation of the forming section, adapted to the geometry of the workpiece or the part to be produced. In particular, the curvature of the shape of the part may differ from the curvature of at least one shape of the base section in terms of amount and / or sign. Thus, since the forming section has a change in curvature compared to the base section, the forming section and the base section extend at least partially in different directions from each other. The shape of the forming section or the shape of the base section refers to the general shape of the respective sections. Shape deviations, preferably at least second and / or at least third and higher order shape deviations as described in DIN 4760:1982-06, are not considered part of the shape or part of the shape curvature. A second-order shape deviation is waviness, and a third- to fifth-order shape deviation is roughness. Therefore, the curvature of the shape is not a membrane defect, particularly a surface defect. In particular, the curvature of the shape of the shaping section is at least partially smaller or larger than the curvature of at least one of the shapes of the base section, preferably the curvature of the shape of the edge region of the base section adjacent to the shaping section, by at least 1.05 times, preferably at least 1.25 times, more preferably at least 2 times, more preferably at least 4 times, more preferably at least 10 times, more preferably at least 25 times, more preferably at least 50 times, more preferably at least 100 times, more preferably at least 250 times, more preferably at least 500 times, more preferably at least 1000 times, more preferably at least 2500 times, more preferably at least 5000 times, in particular at least 10000 times.

[0052] The at least partial deviation of the curvature between the shape of the shaping section and at least one curvature of the shape of the base section is advantageously generated by a pre-plastic deformation of the shaping section relative to the base section, and therefore should not be, or at least should not substantially be, a deviation of the curvature due to, for example, elastic deformation of the membrane, in particular gravity.

[0053] It may also be provided that, at least in the open position, the curvature of the shape of the molding section on the side of the molding section adjacent to the cavity is at least partially different from at least one curvature of the shape of the base section, preferably from the curvature of the shape of the edge region of the base section on the side of the base section adjacent to the cavity, and / or the curvature of the shape of the molding section on the side of the molding section adjacent to the working space is at least partially different from at least one curvature of the shape of the base section, preferably from the curvature of the shape of the edge region of the base section on the side of the base section adjacent to the working space. This provides a pre-deformation of the molding section that is adapted to the geometry of the workpiece or molded part to be produced. In this case, it is particularly advantageous if both the curvature on each side adjacent to the working space and the curvature on each side adjacent to the cavity are different from each other, since this allows for a particularly wide range of adaptation of the molding section to the geometry of the workpiece or molded part to be produced.

[0054] A further embodiment of the device provides that, at least in the open position, the curvature of the shape of the forming section, in particular along the longitudinal and / or lateral extension of the membrane, is designed at least partially opposite to at least one curvature of the shape of the base section, preferably the curvature of the shape of the edge region of the base section adjacent to the forming section. This provides a pre-deformation of the forming section that is adapted to the geometry of the workpiece or part to be produced. In particular, this provides a forming section that is pre-deformed to adapt to more complex geometries of the workpiece or part to be produced. Opposite curvature is understood to mean the definition already given in connection with the press section.

[0055] The at least partially reverse curvature between the shape of the shaping section and at least one curvature of the shape of the base section is advantageously generated by a pre-plastic deformation of the shaping section, in particular relative to the base section, so that the reverse curvature should not, or at least should not, be caused by, for example, an elastic deformation of the membrane, in particular due to gravity.

[0056] It may also be provided that, at least in the open position, the curvature of the shape of the molding section on the side of the molding section adjacent to the cavity is at least partially opposite to at least one curvature of the shape of the base section, preferably the curvature of the shape of the edge region of the base section adjacent to the molding section on the side of the base section adjacent to the cavity, and / or the curvature of the shape of the molding section on the side of the molding section adjacent to the working space is at least partially opposite to at least one curvature of the shape of the base section, preferably the curvature of the shape of the edge region of the base section adjacent to the molding section on the side of the base section adjacent to the working space. This provides a pre-deformation of the molding section that can be adapted to the geometry of the workpiece or molded part to be produced. In this case, it is particularly advantageous if both the curvature on each side adjacent to the working space and the curvature on each side adjacent to the cavity are designed to be opposite to each other, since this allows for a particularly wide range of adaptation of the molding section to the geometry of the workpiece or molded part to be produced.

[0057] According to a further embodiment of the device, it is provided that at least one curvature of the shape of the base section, preferably the deviation of the curvature of the shape of the forming section from the curvature of the shape of the edge region of the base section adjacent to the forming section, is generated by plastic deformation of the forming section, in particular by plastic deformation of the shape of the forming section. Thus, the deviation of the curvature, i.e., the amount and / or sign of the curvature, should be generated by pre-plastic deformation of the forming section. As a result, the forming section is permanently adapted to the geometry of the workpiece or part to be produced.

[0058] Further embodiments of the device provide that the cavity is sealed by at least one seal, at least in the closed position, and / or that the device includes at least one device for varying the pretension of the membrane. Each seal provides a simple structural solution to prevent the working medium from leaking out of the cavity. The device for varying the pretension of the membrane has the advantage that the membrane is in uniform contact with the workpiece, particularly before or when applying temperature and pressure to the workpiece. The device for varying the pretension of the membrane may be realized, for example, by a spring with an adjustable spring deflection or an adjustable pretension. Regarding the seal, it may also be provided that the sealing force can be applied to the membrane by the seal, and preferably the membrane can be moved relative to the seal. Because the membrane is movable relative to the seal, changes in length of the membrane, especially due to thermal expansion or contraction, do not result in excessive stress on the membrane or uneven contact with the workpiece or the molded part to be produced. Furthermore, the mobility of the membrane relative to the seal simplifies applying pretension to the membrane. This is because in this case the pretensioning force can be applied to the membrane outside the area sealed by the seal. Advantageously, the device comprises at least one device for varying the sealing force of the seal. In this way, a particularly tight seal of the cavity can be achieved.

[0059] The object stated at the outset is also achieved by a method for producing molded articles, in particular from fiber composite materials, comprising the steps of a) providing a workpiece, b) providing an apparatus for producing molded articles as claimed in any one of claims 1 to 14, and c) applying pressure and / or temperature to the workpiece by means of the apparatus for producing molded articles. The method advantageously further comprises the step of b1) inserting the workpiece into the apparatus for producing molded articles. Preferably, the workpiece is inserted into the working space in step b1). Furthermore, in step b1), the press tool is advantageously in an open position. The method preferably also comprises the step of b2) moving the first press tool and the second press tool from the open position to the closed position. Steps b1) and / or b2) are preferably performed after steps a) and / or b). Alternatively or additionally, steps b1) and / or b2) are preferably performed before step c). Furthermore, step b1) is preferably performed before step b2).

[0060] The invention will now be explained in more detail with reference to the drawings, which show only preferred embodiments. [Brief explanation of the drawings]

[0061] [Figure 1] 1 is a cross-sectional view of a first embodiment of an apparatus for producing a molded article, the apparatus having a press die in an open position. [Figure 2] 2 is a diagram of the apparatus shown in FIG. 1 with a workpiece inserted into the workspace of the apparatus and with the press die of the apparatus in an open position. [Figure 3] 2 is a diagram of the apparatus shown in FIG. 1 with a workpiece inserted into the workspace of the apparatus and with the press die of the apparatus in a closed position. [Figure 4] FIG. 2 is a cross-sectional view of a second embodiment of an apparatus for producing a molded article, with the press die of the apparatus in an open position. [Figure 5]5 is a view of the apparatus shown in FIG. 4 with a workpiece inserted into the workspace of the apparatus and with the press die of the apparatus in an open position. [Figure 6] 5 is a view of the apparatus shown in FIG. 4 with a workpiece inserted into the workspace of the apparatus and with the press die of the apparatus in a closed position. [Figure 7] FIG. 10 is a cross-sectional view of a portion of a third embodiment of an apparatus for producing a molded article, with the press die of the apparatus in a closed position.

[0062] 1 shows a first embodiment of an apparatus 1 for producing molded parts in a cross-sectional view, with the press dies 2, 3 of the apparatus in the open position, and no workpieces have yet been inserted into the apparatus.

[0063] The apparatus 1 comprises an upper first press die 2 and a lower second press die 3. The two press dies 2, 3 may be moved relative to one another, for example vertically (as indicated by the arrows in Figure 1), between an open position and a closed position along a movement axis B. In the illustrated configuration, it is sufficient for only one press die of the two press dies 2, 3, in particular the first press die 2, to be movably mounted. The movement axis B may extend vertically, for example, as shown in Figure 1.

[0064] Furthermore, the apparatus 1 includes a membrane 4, which in this embodiment is connected to the first press die 2. Alternatively to the embodiment shown in FIG. 1, the membrane 4 can be connected to a second press die 3, for example. A cavity 5 for a working medium, e.g., oil, is formed between the membrane 4 and the first press die 2. The membrane 4 is made of metal and preferably has a thickness in the range of 0.05 mm to 4 mm. The cavity 5 can be filled with the working medium via a passage 6. Both the first press die 2 and the second press die 3 are provided with holes 7 through which a heating medium and / or a cooling medium can pass. Alternatively or additionally, the first press die 2 and / or the second press die 3 can be equipped with a heating element, in particular an insertable heating plate, which can be inserted into the respective press die 2, 3.

[0065] In the design of the device 1 shown in Figure 1, a working space 8 is formed between the two press dies 2, 3, in this case in particular between the membrane 4 and the second press die 3. A workpiece (not shown in Figure 1) can be inserted into the working space. The two press dies 2, 3 preferably have guides 9, which can be formed, for example, by a protrusion 9A and a recess 9B, where the protrusion 9A can be provided on the second press die 3 and the recess 9B can be provided on the first press die 2.

[0066] In this embodiment, the surfaces of the first press die 2 and the second press die 3 have first press sections P1, P1', second press sections P2, P2', and third press sections P3, P3', respectively. The press sections P1, P2, P3 of the first press die 2 are adjacent to the cavity 5, and the press sections P1', P2', P3' of the second press die 3 are adjacent to the working space 8. However, it may be sufficient if only one of the press dies 2, 3 has a designed surface with each of the press sections P1, P1', P2, P2', P3, P3'.

[0067] The second press section P2, P2' and the third press section P3, P3' of the two press dies 2, 3 are at least partially spaced apart from the first press section P1, P1' of each press dies 2, 3. The curvatures of the shapes of the second press sections P2, P2' of the two press dies 2, 3 are at least partially different and at least partially opposite to the curvatures of the shapes of the respective first press sections P1, P1' and the respective third press sections P3, P3'.

[0068] The second press section P2, P2' of each of the two press dies 2, 3 comprises a first bending point KP1, KP1' and a second bending point KP2, KP2'. In the region of the bending points KP1, KP1', KP2, KP2', the shape of the second press section P2, P2' has a different curvature compared to the shapes of the first press section P1, P1' and the third press section P3, P3', both in terms of the amount and the sign of the curvature. Thus, the first press section P1, P1' and the third press section P3, P3' have zero curvature, in particular in the edge region adjacent to each second press section P2, P2', since the first press section P1, P1' and the third press section P3, P3', respectively, extend in a straight line. On the other hand, the second press section P2, P2' has a curvature and thus a curvature deviation that is not equal to zero in the region of the bending points KP1, KP1', KP2, KP2' compared to the respective first press section P1, P1' and third press section P3, P3'. However, respective bending points may also be provided in each of the first press sections P1, P1' and / or third press sections P3, P3'.

[0069] In this embodiment, the second press sections P2, P2' do not extend parallel to the respective first press sections P1, P1' and the respective third press sections P3, P3', but rather extend at a partial incline. In the illustrated embodiment, there is an angle of 45° between each second press section P2, P2' and each first press section P1, P1', and between each second press section P2, P2' and each third press section P3, P3'.

[0070] In the illustrated embodiment, the membrane 4 is connected to the first press die 2 as follows: the first press die 2 has a peripheral edge element 10 connected to it, in particular by a screw connection (the screw connection is not shown in FIG. 1 ). A gap 11 is formed between the first press die 2 and its edge element 10, through which the membrane 4 is guided. The gap 11 opens into a cavity 12, in which a clamping device 13 is provided for clamping the membrane 4 therein. The clamping device 13 is connected to a tie rod 14, which leads out of the first press die 2 and the edge element 10 through the opening and is pressed outward by a spring 15 supported on the outside, thereby providing a pretension to the membrane 4. The spring 15 is part of a device for varying the pretension of the membrane 4.

[0071] To seal the cavity 5, a seal 16 is provided in the gap 11, which seal 16 allows the membrane 4 to be displaced. The seal 16 presses against the membrane 4 with a sealing force. In order to vary this sealing force, in this case a device 17 for varying the sealing force of the seal 16 is provided.

[0072] In the present view shown in Figure 1, the lateral axis Q of the membrane 4 extends from left to right, the longitudinal axis L of the membrane 4 extends into the image plane of Figure 1, and the height axis H of the membrane 4 extends from bottom to top. The axes are marked accordingly in Figure 1 and in the subsequent figures. Thus, in Figure 1, the lateral extension of the membrane 4 extends substantially from left to right or right to left, and the longitudinal extension of the membrane 4 extends substantially into or out of the image plane of Figure 1. The lateral axis Q of the film 4, the lateral axis of the apparatus 1, the lateral axis of the first press die 2, and the lateral axis of the second press die 3, the longitudinal axis L of the film 4, the longitudinal axis L of the apparatus 1, the longitudinal axis of the first press die 2, and the longitudinal axis of the second press die 3, and the height axis H of the film 4, the height axis H of the apparatus 1, the height axis of the first press die 2, and the height axis of the second press die 3 each extend in the same direction in this embodiment (as well as in other embodiments), so the same reference numerals are used for each axis in the illustrated configuration. Thus, the lateral extension of the press dies 2, 3 also extends substantially from left to right or right to left, and the longitudinal extension of the press dies 2, 3 also extends substantially into or out of the image plane of FIG. 1.

[0073] The membrane 4 has at least one elastically deformable base section G, G' for contacting the workpiece, in particular the molded part to be produced, and at least one pre-plastically deformed forming section F for contacting the workpiece, in particular the molded part to be produced. In the embodiment of the apparatus 1 shown in the drawings, a first base section G is provided along the transverse extension of the membrane 4, a forming section F is provided adjacent to the first base section G, and a second base section G' is provided adjacent to the forming section F. This forming section F is pre-plastically deformed relative to the base sections G, G'. As a result of the pre-plastic deformation, the forming section F is given a shape different from that of at least one of the base sections G, G', preferably both base sections G, G'. In this embodiment, this forming section F does not extend parallel to the base sections G, G', but extends partially obliquely relative to the base sections G, G'. The pre-plastic deformation of the forming section F enables workpieces with complex geometries to be processed by the apparatus 1 and molded parts with complex geometries to be produced. In particular, in the case of a device 1 in which the membrane 4 is made of metal, only a certain degree of elastic deformation of the membrane 4 is possible in order to follow the shape of a workpiece having a complex geometry or of a molded part to be produced.

[0074] The pre-plastic deformation of the forming section F makes the base sections G, G' more elastically deformable than the forming section F. The base sections G, G' can be deformed more strongly in the direction of the working space 8 by elastic deformation, in particular linear elastic deformation, compared to the forming section F. Nevertheless, the forming section F can continue to deform elastically at least to some extent.

[0075] In this case, the forming section F has bending points K, K' in each of its outer regions along the transverse extension of the membrane 4. The bending points K, K' in the membrane 4 are generated by a pre-plastic deformation of the forming section F relative to the base sections G, G'. In the region of the bending points K, K', the shape of the forming section F has a curvature that differs from the shape of the base sections G, G' in terms of both the amount of curvature and the sign of the curvature. For example, the base sections G, G', and in particular the edge regions of each base section G, G' adjacent to the forming section F, have a curvature of zero, since the base sections G, G', respectively, are straight. On the other hand, the forming section F has a curvature in the region of the bending points K, K' that is not equal to zero, and thus a deviation in curvature relative to the base sections G, G'.

[0076] In the configuration shown, deviations in curvature and the presence of opposite curvatures exist both between the curvature of the shape of the molding section F on the side of the molding section F adjacent to the cavity 5 and the curvature of the shape of the base sections G, G' on the side of the base sections G, G' adjacent to the molding section F, preferably in any case the curvature of the shape of the edge regions of the base sections G, G' adjacent to the molding section F, and also between the curvature of the shape of the molding section F on the side of the molding section F adjacent to the working space 8 and the curvature of the shape of the base sections G, G' on the side of the base sections G, G' adjacent to the working space 8, preferably the curvature of the shape of the edge regions of the base sections G, G' adjacent to the molding section F.

[0077] In the present case, the molding section F extends, in any case, partially inclined relative to the base sections G, G', in particular at an angle of 45° in the illustrated configuration. In this case, in particular on the side of the molding section F adjacent to the cavity 5 and on the side of the molding section F adjacent to the working space 8, the molding section F is, in any case, at least partially spaced apart from the first base section G, in particular from the edge region of the first base section G adjacent to the molding section F, in the direction of the cavity 5, in particular substantially perpendicular to the surface of the edge region of the first base section G, and from the second base section G', in particular from the edge region of the second base section G' adjacent to the molding section F, in the direction of the working space 8, in particular substantially perpendicular to the surface of the edge region of the second base section G', a distance which corresponds at least to the thickness of the film.

[0078] The at least partial deviation of the curvature between the shape of the forming section F and the shape of the base sections G, G' is in this case caused by a plastic deformation, in particular a pre-plastic deformation, of the forming section F. Despite this plastic or pre-plastic deformation, the thickness of the film of the forming section F differs from the thickness of the base sections G, G' by no more than 40%.

[0079] Figure 2 shows the apparatus of Figure 1 with a workpiece 18 inserted into the working space 8 of the apparatus 1 and with the press dies 2, 3 of the apparatus 1 in the open position. The areas of the apparatus 1 already mentioned above are given the respective reference numerals in Figure 2. The difference from Figure 1 is that the workpiece 18 has been inserted into the working space 8.

[0080] FIG. 3 shows the apparatus 1 of FIG. 1 with a workpiece 18 inserted into the working space 8 of the apparatus 1 and the press dies 2 and 3 of the apparatus 1 in the closed position. The previously mentioned areas of the apparatus 1 are also labeled with the respective reference numerals in FIG. 3. The apparatus 1 is closed, and the two press dies 2 and 3 are therefore in the closed position by moving them toward each other. In the closed position shown in FIG. 3, pressure and temperature are applied to the workpiece 18. Pressure is applied by supplying a working medium, e.g., oil, into the cavity 5 through the passage 6, which presses the membrane 4 toward the workpiece 18. Temperature can be applied in various ways. One possibility is to heat the working medium supplied into the cavity 5 through the passage 6, thereby transferring heat from the working medium in the cavity 5 through the membrane 4 to the workpiece 18. Conversely, the working medium can be cooled to cool the workpiece 18. Alternatively or additionally, it may be provided that a heating medium and / or a cooling medium flows through the holes 7, whereby the two press dies 2, 3 may be heated or cooled, and subsequently the workpiece 18 may be heated or cooled.

[0081] FIG. 4 shows a cross-sectional view of a second embodiment of an apparatus 1 for producing molded articles, with the press dies 2, 3 of the apparatus 1 in the open position. A workpiece 18 has not yet been inserted into the working space 8 of the apparatus 1. The second embodiment of the apparatus 1 shown in FIG. 4 differs from the first embodiment of the apparatus 1 previously shown in FIGS. 1 to 3 essentially in the shape of the press dies 2, 3, in particular the shape of the press sections P1, P1', P2, P2', P3, P3', and the shape of the membrane 4. Identical components in the different embodiments are also provided with the same reference numerals. In the following, essentially only the differences between the different embodiments will be explained in more detail.

[0082] In the second embodiment of the apparatus 1, the press sections P1, P1', P2, P2', P3, P3' have a shape formed, in particular, by multiple circular arcs. The two press dies 2, 3 themselves also have a shape formed, in particular, at least partially by multiple circular arcs. However, the shapes of the press dies 2, 3 on the side opposite the cavity 5 and / or the working space 8 may be designed differently. In any case, the second press section P2, P2' of the press dies 2, 3 has a substantially S-shaped shape. The shapes of the second press sections P2, P2', as well as the shapes of the first press sections P1, P1' and the third press sections P3, P3', are adapted to the complex geometry of the workpiece 18 that may be inserted into the working space 8 of the apparatus 1 and the molded part to be produced from this workpiece 18. The curvature of the shape of the second press section P2, P2' is in any case designed at least partially different, in particular at least partially opposite, to the curvature of the shape of each of the first press section P1, P1' and each of the third press sections P3, P3', in particular the curvature of the shape of each of the edge regions of each of the first press section P1, P1' and each of the third press sections P3, P3' adjacent to each of the second press sections P2, P2'. For example, the curvature of the shape of the second press section P2, P2' in the region of the third bending point KP3, KP3' runs opposite to at least one curvature of the shape of each of the first press section P1, P1' and each of the third press sections P3, P3'. Due to the complexity of the shape of each of the second press sections P2, P2', it may be possible to divide the second press section P2, P2' into further press sections.

[0083] Furthermore, in this embodiment, the membrane 4 partially has a shape formed in particular from a number of circular arcs. The base sections G, G' have a substantially continuous curvature due to elastic deformation, in this case caused by gravity. The pre-plastically deformed forming section F has a substantially S-shaped shape due to pre-plastic deformation, in particular for the base sections G, G'. The shape of the forming section F is adapted to the complex geometry of the workpiece 18 and the formed part to be produced from this workpiece 18. The curvature of the shape of the forming section F is designed at least partially different, in particular at least partially opposite, to the curvature of the edge regions of the respective base sections G, G' adjacent to the forming section F along the transverse extension of the membrane 4. Thus, the curvature of the shape of the forming section F in the region of the first bending point K and the third bending point K'' of the membrane 4 extends in the opposite direction to the curvature of the shape of the base sections G, G'.

[0084] Figure 5 shows the apparatus 1 of Figure 4, with a workpiece 18 inserted into the working space 8 of the apparatus 1 and with the press dies 2, 3 of the apparatus 1 in the open position. The areas of the apparatus 1 already described above are marked with the respective reference numerals in Figure 4. The difference from Figure 4 is that the workpiece 18 has been inserted into the working space 8.

[0085] Figure 6 shows the apparatus 1 of Figure 4, with a workpiece 18 inserted into the working space 8 of the apparatus 1 and the press dies 2, 3 of the apparatus 1 in the closed position. The regions of the apparatus 1 already mentioned are given the respective reference numerals in Figure 6. According to Figure 3 of the first embodiment, the apparatus 1 is closed. The explanation for Figure 3 can be applied correspondingly to Figure 6.

[0086] FIG. 7 shows a partial cross-section of a third embodiment of the apparatus 1 for producing molded articles, with the press dies 2, 3 of the apparatus 1 in the closed position and a workpiece 18 inserted in the working space 8. The third embodiment of the apparatus 1 shown in FIG. 7 differs substantially from the first embodiment of the apparatus 1 previously shown in FIGS. 1 to 3 and the second embodiment of the apparatus 1 shown in FIGS. 4 to 6 in terms of the shape of the press dies 2, 3, in particular the shape of the press sections P1, P1', P2, P2', P3, P3', and the shape of the membrane 4. Identical components between the embodiments are also provided with the same reference numerals. In particular, the non-illustrated regions of the apparatus 1 of this third embodiment can be designed as shown in FIGS. 1 to 6. In the following, substantially only the differences between the embodiments compared to the previous embodiments will be explained in more detail.

[0087] In this third embodiment, both the shape of the first press section P1, P1' and the shape of the third press section P3, P3' are arcuate. The second press sections P2, P2' are designed differently, i.e., the curvature of the shape of each second press section P2, P2' is at least partially different and opposite to the curvature of the shape of each adjacent first press section P1, P1' and third press section P3, P3'. For example, the curvature of the shape of the second press section P2, P2' in the region of the first bending points KP1, KP1' extends in the opposite direction to the curvature of the shape of each first press section P1, P1' and each third press section P3, P3'. In the illustrated embodiment, the second press sections P2, P2' are each approximately S-shaped and include straight regions, but the second press sections P2, P2' may each have a substantially continuously curved shape.

[0088] The pre-plastically deformed forming section F has a substantially S-shaped shape due to the pre-plastic deformation, particularly with respect to the base sections G, G'. Although the forming section F has straight regions, the forming section F may also have a substantially continuously curved shape. The shape of the forming section F is adapted to the complex geometry of the workpiece 18 and the molded part to be produced from this workpiece 18. Furthermore, the curvature of the shape of the forming section F along the lateral extension of the membrane 4 is at least partially opposite to the curvature of the shape of the edge regions of each of the base sections G, G' adjacent to the forming section F. For example, in the region of the first bending point K of the membrane 4, the curvature of the shape of the forming section F extends in the opposite direction to the curvature of the shape of the base sections G, G'. [Explanation of symbols]

[0089] 1. Equipment for producing molded articles 2. First press die 3 Second press die 4 membrane 5 cavities 6 aisles 7 holes 8. Workspace 9 Guide 9A Convex part 9B Recess 10 Edge Elements 11 Gap 12 Cavity 13 Fastening device 14 tie rod 15 Spring 16 Seals 17 Device for varying the sealing force 18 workpieces B Movement axis F Molding category G, G' Basic classification H Height axis K, K', K'' membrane bending points KP1, KP1', KP2, KP2', KP3, KP3' Press die bending points L Longitudinal axis P1, P1' First press section P2, P2' Second press section P3, P3' Third press section Q Lateral axis

Claims

1. In particular, an apparatus (1) for producing molded products from fiber composite materials, - The first press die (2), - The second press die (3), - At least one partially elastically deformable film (4) for contacting the workpiece (18) Equipped with, - The first press die (2) and the second press die (3) are relatively movable relative to each other along the movement axis (B) between the open position and the closed position. - At least in the closed position, a cavity (5) for the working medium is formed between the membrane (4) and the first press die (2) and / or the second press die (3), - A workspace (8) for housing the workpiece (18) is formed between the first press die (2) and the second press die (3). - The surface of the first press die (2) and / or the surface of the second press die (3) comprises a first press section (P1, P1') and a second press section (P2, P2'), - The first press section (P1, P1') and the second press section (P2, P2') are adjacent to the work space (8) and / or the cavity (5), - The aforementioned film (4) is made from metal, - The second press section (P2, P2') is at least partially separated from the first press section (P1, P1') in the direction of the moving axis (B), - In particular, at least one curvature of the shape of the second press section (P2, P2') along the longitudinal and / or lateral extension of each of the press dies (2, 3) is at least partially different from at least one curvature of the shape of the first press section (P1, P1'), preferably the curvature of the edge region of the first press section (P1, P1') adjacent to the second press section (P2, P2'). In apparatus (1), Apparatus (1), characterized in that the shape of the first press section (P1, P1') and / or the second press section (P2, P2'), particularly the shape of the first press section (P1, P1') and / or the shape of the second press section (P2, P2'), is at least partially curved about at least two axes extending perpendicularly to each other.

2. Apparatus (1) for producing molded articles, particularly from fiber composite materials, - The first press die (2), - The second press die (3), - At least one partially elastically deformable film (4) for contacting the workpiece (18) Equipped with, - The first press die (2) and the second press die (3) are relatively movable relative to each other along the movement axis (B) between the open position and the closed position. - At least in the closed position, a cavity (5) for the working medium is formed between the membrane (4) and the first press die (2) and / or the second press die (3), - A workspace (8) for housing the workpiece (18) is formed between the first press die (2) and the second press die (3). - The surface of the first press die (2) and / or the surface of the second press die (3) comprises a first press section (P1, P1') and a second press section (P2, P2'), - The first press section (P1, P1') and the second press section (P2, P2') are adjacent to the work space (8) and / or the cavity (5), - The aforementioned film (4) is made from metal, - The second press section (P2, P2') is at least partially separated from the first press section (P1, P1') in the direction of the moving axis (B), - In particular, at least one curvature of the shape of the second press section (P2, P2') along the longitudinal and / or transverse extension of each of the press dies (2, 3) is at least partially different from at least one curvature of the shape of the first press section (P1, P1'), preferably the curvature of the edge region of the first press section (P1, P1') adjacent to the second press section (P2, P2'). In apparatus (1), Apparatus (1), characterized in that, at least in the open position, the contact portion of the film (4) intended to contact the workpiece (18) comprises a first end and a second end, the first end and the second end of the contact portion are each adjacent to a free portion of the film (4) not intended to contact the workpiece (18), and the first end of the contact portion is spaced apart from the second end of the contact portion along the moving axis (B).

3. The apparatus (1) according to claim 1 or 2, characterized in that the second press section (P2, P2') is at least partially separated from the first press section (P1, P1') by a distance of at least 5 mm, preferably at least 50 mm, more preferably at least 150 mm, more preferably at least 200 mm, more preferably at least 300 mm, more preferably at least 500 mm, and especially at least 1000 mm in the direction of the movement axis (B).

4. Apparatus (1) according to claim 1 or 2, characterized in that the at least one curvature of the shape of the second press section (P2, P2') along the longitudinal and / or lateral extension of each of the press dies (2, 3) is designed to be at least partially opposite to the at least one curvature of the shape of the first press section (P1, P1'), preferably the curvature of the shape of the edge region of the first press section (P1, P1') adjacent to the second press section (P2, P2'), wherein the apparatus (1) according to claim 1 or 2.

5. The apparatus (1) according to claim 1 or 2, wherein the second press sections (P2, P2') extend at least partially inclined with respect to the first press sections (P1, P1') particularly along the longitudinal and / or lateral extensions of each of the press dies (2, 3), and preferably there exists at least partially an angle of at least 90°, preferably at least 100°, particularly at least 120° and / or at most 180°, preferably at most 160°, particularly at most 145° between the first press sections (P1, P1') and the second press sections (P2, P2').

6. Apparatus (1) according to claim 1 or 2, characterized in that the surface of the first press die (2) and / or the surface of the second press die (3) have a third press section (P3, P3'), preferably the third press section (P3, P3') is at least partially spaced apart from the first press section (P1, P1') and / or the second press section (P2, P2') in the direction of the moving axis (B), and preferably the third press section (P3, P3') is at least partially spaced apart from the first press section (P1, P1') and / or the second press section (P2, P2') by a distance of at least 5 mm, preferably at least 50 mm, more preferably at least 150 mm, more preferably at least 200 mm, more preferably at least 300 mm, more preferably at least 500 mm, and particularly at least 1000 mm, in the direction of the moving axis (B).

7. Apparatus (1) according to claim 6, characterized in that, in particular, at least one curvature of the shape of the third press section (P3, P3') along the longitudinal extension and / or lateral extension of each of the press dies (2, 3) is at least partially different from the at least one curvature of the shape of the first press section (P1, P1'), and / or the at least one curvature of the shape of the third press section (P3, P3') is at least partially different from the at least one curvature of the shape of the second press section (P2, P2'), preferably the curvature of the edge region of the second press section (P2, P2') adjacent to the third press section (P3, P3').

8. Apparatus (1) according to claim 6, characterized in that, in particular, at least one curvature of the shape of the third press section (P3, P3') along the longitudinal extension and / or lateral extension of each of the press dies (2, 3) is designed to be at least partially opposite to the at least one curvature of the shape of the first press section (P1, P1'), and / or in particular, the at least one curvature of the shape of the third press section (P3, P3') along the longitudinal extension and / or lateral extension of each of the press dies (2, 3) is designed to be at least partially opposite to the at least one curvature of the shape of the second press section (P2, P2'), preferably the curvature of the edge region of the second press section (P2, P2') adjacent to the third press section (P3, P3').

9. The apparatus (1) according to claim 6, characterized in that the third press section (P3, P3') extends at least partially inclined with respect to the first press section (P1, P1') and / or the second press section (P2, P2') along the longitudinal and / or lateral extension of each of the press dies (2, 3), preferably with respect to the first press section (P1, P1') and / or the second press section (P2, P2'), and preferably there exists at least partially an angle of at least 90°, preferably at least 100°, particularly at least 120° and / or at most 180°, preferably at most 160°, particularly at most 145° between the third press section (P3, P3') and the first press section (P1, P1') and / or the second press section (P2, P2').

10. The apparatus (1) according to claim 1 or 2, characterized in that the shape of the first press section (P1, P1'), the second press section (P2, P2'), and / or the third press section (P3, P3'), in particular the shape of the first press section (P1, P1'), the shape of the second press section (P2, P2'), and / or the shape of the third press section (P3, P3'), is at least partially curved about the longitudinal axis (L) of the apparatus (1) or an axis parallel to the longitudinal axis (L) of the apparatus (1), about the lateral axis (Q) of the apparatus (1) or an axis parallel to the lateral axis (Q) of the apparatus (1), and / or about the height axis (H) of the apparatus (1) or an axis parallel to the height axis (H) of the apparatus (1).

11. The apparatus (1) according to claim 1 or 2, wherein the film (4) has at least one elastically deformable base section (G, G') for contacting the workpiece (18), particularly along the longitudinal and / or transverse extension of the film (4), and at least one pre-plastically deformed molded section (F) for contacting the workpiece (18), and preferably, at least in the open position, the molded section (F) is pre-plastically deformed relative to the base section (G, G'), particularly along the longitudinal and / or transverse extension of the film (4).

12. The apparatus (1) according to claim 11, characterized in that, at least in the open position, the curvature of the shape of the molded section (F) along the longitudinal and / or transverse extension of the film (4) is at least partially different from the curvature of at least one of the shapes of the base sections (G, G'), preferably the curvature of the edge region of the base sections (G, G') adjacent to the molded section (F).

13. The apparatus (1) according to claim 11, characterized in that, at least in the open position, the curvature of the shape of the molded section (F) along the longitudinal and / or transverse extension of the film (4) is designed to be at least partially opposite to the curvature of at least one of the shapes of the base sections (G, G'), preferably the curvature of the edge region of the base sections (G, G') adjacent to the molded section (F).

14. The apparatus (1) according to claim 12, characterized in that the deviation of the curvature of the shape of the molding section (F) from the curvature of the shape of the base section (G, G'), preferably from the curvature of the shape of the edge region of the base section (G, G') adjacent to the molding section (F), is caused by plastic deformation of the molding section (F), particularly plastic deformation of the shape of the molding section (F).

15. The apparatus (1) according to claim 1 or 2, wherein the cavity (5) is sealed by at least one seal (16) at least in the closed position, and / or the apparatus (1) comprises at least one device for changing the pretension of the membrane (4).

16. In particular, a method for producing molded products from fiber composite materials, a) A step of preparing the workpiece (18), b) A step of preparing an apparatus (1) for producing a molded article according to claim 1 or 2, c) The step of applying pressure and / or temperature to the workpiece (18) by the apparatus (1) for producing a molded product; Methods that include...

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