Method for manufacturing a hybrid component

Abstract

Method for manufacturing a hybrid component (10) made from at least two different materials, the method comprising the following steps: - Providing a substrate (11, 20) made of a substrate material onto which at least one functional element (12) is to be applied in a functional area of ​​the substrate (11, 20), - wherein the substrate material is a fiber composite comprising a fiber material and a thermosetting matrix material embedding the fiber material, - Creating a first functional layer (21) from a thermosetting resin system (21) onto the substrate (11,20) at least within the functional area of ​​the substrate (11,20), - wherein the thermosetting functional layer (21) is subsequently applied to the substrate which has already been fully consolidated and - wherein the thermoset functional layer (21) is attached via remaining reactive groups of the substrate, - Applying at least one second functional layer (22) made of a thermoplastic material (22) to the first functional layer (21), - wherein the thermosetting resin system (21) and the thermoplastic material (22) are selected such that both form a metallurgical bond after consolidation, and - Applying a thermoplastic material different from the substrate material to this second functional layer (22) produced on the substrate (11,20) in order to produce the functional element (12) on the substrate (11,20).

Description

[0001] The invention relates to a method for manufacturing a hybrid component made from at least two different materials.

[0002] Additive manufacturing, also known as 3D printing, is an emerging manufacturing process that is increasingly being used to produce components for applications in the transportation sector, particularly in aerospace. Compared to conventional manufacturing methods, additive manufacturing technologies offer enormous potential for mass production, cost reduction, and supply chain simplification, as they provide the ability to produce parts on demand locally without the need for costly warehousing facilities.

[0003] One disadvantage of additive manufacturing is the significantly slower production rates compared to conventional manufacturing techniques, which makes economically viable applications of additively manufactured parts more difficult. Furthermore, additive manufacturing processes can generally only produce components that are integrally made from a single material. Hybrid components, which are made from two or more different materials, cannot be adequately manufactured using additive manufacturing processes.

[0004] Such hybrid components often consist of a base substrate to which at least one functional element is attached. These functional elements are made of a material different from that of the base substrate. This allows for the production of components where the material selection is tailored to the specific function of the functional element, thus optimizing them either for stability / stiffness and / or weight, or providing additional functions such as electrical conductivity, defined thermal conductivity, or sensory properties.

[0005] US Patent 2016 / 0325380 A1 discloses a method for manufacturing a component composed of several materials. In this process, a first component made of a first material is produced, onto which a second component made of a second material is applied. A disadvantage of this method is that only chemically compatible materials can be used to ensure a durable bond between the components. Furthermore, in applications where the final component is exposed to temperature fluctuations, the differing coefficients of thermal expansion of the materials lead to differential expansion and contraction, resulting in stresses that may ultimately cause the bond to fail.

[0006] German patent DE 10 2013 114 829 A1 discloses a method for manufacturing a hybrid component in which a thermoplastic component is to be attached to a thermoset component. For this purpose, a multilayer functional layer is applied to the thermoset component, which includes at least one thermoplastic material, in order to enable the thermoplastic component to be attached to this functional layer.

[0007] DE 10 2018 121 336 A1 relates to a method for manufacturing a fiber composite component, wherein a film-like adhesion promoter is first provided, to which a functional element is attached on a first side surface. Subsequently, a fiber preform is applied to the film-like adhesion promoter on the second side surface.

[0008] JP S63-295692A describes a process for coating metallic components to provide corrosion protection. First, the oxide layer is removed by sandblasting and chromating. Then, an epoxy resin primer is applied, followed by a two-layer PE film.

[0009] German patent DE 10 2018 100 620 A1 describes a component made of a fiber-reinforced thermoplastic material onto which a polyetheretherketone (PEEK) film is applied and consolidated with the thermoplastic material of the component to create a metallurgical bond between the PEEK film and the component. PEEK is a high-performance thermoplastic material.

[0010] Against this background, the object of the present invention is to provide an improved method by which hybrid components made of different materials can be manufactured with a durable connection.

[0011] The problem is solved by the method for manufacturing a hybrid component according to claim 1 according to the invention. Advantageous embodiments of the invention are then found in the corresponding dependent claims.

[0012] According to claim 1, a method for manufacturing a hybrid component is proposed, which is made from at least two different materials. One of the materials is a thermoplastic material, while the other material is a thermoset material. The other material is not a thermoplastic material, so that the hybrid component is made from a thermoplastic material and a non-thermoplastic material. These thermoset and / or thermoplastic materials can be provided with fillers, e.g., short or continuous fibers made of glass, carbon fiber, aramid, basalt, or other materials (including nanoparticles).

[0013] The method according to the invention comprises the following steps: - Providing a substrate made of a (non-thermoplastic) substrate material onto which at least one functional element is to be applied in a functional area of ​​the substrate, - wherein the substrate material is a fiber composite comprising a fiber material and a thermosetting matrix material embedding the fiber material, - Creating a first functional layer from a thermosetting resin system onto the substrate, at least within the functional area of ​​the substrate, - wherein the thermosetting functional layer is subsequently applied to the already fully consolidated substrate and - wherein the thermoset functional layer is bound via remaining reactive groups of the substrate, - Applying at least one second functional layer made of a thermoplastic material to the first functional layer, - wherein the thermosetting resin system and the thermoplastic material are selected such that both form a metallurgical bond after consolidation, and - Applying a thermoplastic material different from the substrate material to this second functional layer produced on the substrate in order to produce the functional element on the substrate.

[0014] Accordingly, a substrate made of a substrate material is first provided, onto which at least one functional element is to be applied in a functional area of ​​the substrate. The functional element is to be made of a thermoplastic material, while the substrate is made of a different substrate material that is not a thermoplastic material. In a particularly preferred embodiment, the functional element is produced directly on the second functional layer by applying the thermoplastic material using an additive manufacturing process, e.g., in the form of 3D printing.

[0015] To ensure a reliable and process-safe bond when applying the functional element made of thermoplastic material, a first functional layer of a thermoset resin system is applied to the substrate within the functional area. It is advantageous if the thermoset resin system is compatible with the substrate material in such a way that the two form a cohesive bond. Ideally, the thermoset resin system chemically bonds with the substrate material, resulting in a strong and secure connection between the substrate and the first functional layer.

[0016] In a second step, a second functional layer made of a thermoplastic material is applied to this first functional layer. The thermoset resin system and the thermoplastic material are selected such that they form a metallurgical bond after curing. This means that the first and second functional layers form a chemical bond, for example, through diffusion and / or covalent bonds between the thermoset resin system and the thermoplastic material, thus creating a functional composite between the first and second functional layers.

[0017] The functional element, which is also made of a thermoplastic material or consists of such a material or has such a material, can now be applied to this second functional layer made of a thermoplastic material produced on the substrate and bonded to the second functional layer in a material-bonded manner.

[0018] The present invention therefore makes it possible to firmly and securely attach a thermoplastic functional element to a provided substrate in order to produce a corresponding hybrid component. The first and second functional layers ensure that the thermoplastic functional element can be firmly and securely attached to the substrate even if the substrate material is not thermoplastic.

[0019] A material-bonded connection between the first functional layer and the second functional layer is understood in particular to mean that the thermosetting resin system of the first functional layer and the thermoplastic material of the second functional layer form a chemical bond, for example via a diffusion connection and / or through covalent bonds.

[0020] Both the thermosetting resin system and the thermoplastic material are therefore chosen in such a way that a material-bonded connection is possible between the two materials.

[0021] Suitable materials for the thermoplastic functional layer include PEI (polyetherimide), PES (polyethersulfone), PSU (polysulfone), and PA (polyamide), as these exhibit good chemical compatibility with the epoxy resin molecules. It has been shown that many thermoplastic materials are compatible with these systems, meaning that the subsequently applied thermoplastic functional element does not necessarily have to be a PEI, but can also be a material from the polyaryletherketone group (PAEK, e.g., PEEK) or thermoplastics from other material groups.

[0022] It therefore becomes possible to attach functional elements made of a thermoplastic material to a substrate even when direct adhesion is not possible due to the substrate material's incompatibility with the thermoplastic. These gaps can be bridged by applying the first and second functional layers and creating a corresponding functional composite.

[0023] In the context of the present invention, consolidation refers in particular to the hardening of the matrix in thermoset materials. This means, in particular, that true chain links are formed or newly established (crosslinked) between the molecules. In the case of thermoplastic materials, consolidation refers in particular to the hardening or solidification of the material, which melts upon application of heat and solidifies again upon cooling.

[0024] According to one embodiment, it is provided that the first and second functional layers are consolidated before the thermoplastic material is applied to produce the thermoplastic functional element.

[0025] By curing the first and second functional layers in a preferably joint curing process (co-curing), it can be ensured that the two materials form a material-bonded connection, for example in the form of a chemical bond, thus establishing a firm and stable connection.

[0026] According to one embodiment, the thermosetting resin system is an epoxy resin system and / or the thermoplastic material is a PEI, PSU, PES or PA.

[0027] According to one embodiment, the thermoplastic material is applied to the first functional layer in the form of a thermoplastic film.

[0028] According to the invention, the substrate material is a thermosetting plastic, or consists of one, or has one.

[0029] According to the invention, the substrate material comprises a fiber composite material, a fiber material, and a matrix material embedding the fiber material. Such a fiber composite material can, for example, be a CFRP or GFRP with a thermosetting plastic as the matrix material.

[0030] According to the invention, the matrix material is a thermoset matrix material. Particularly with a thermoset matrix material, the present invention offers the advantage that a functional element made of a thermoplastic material can be firmly and securely attached to the thermoset substrate, thereby ensuring a firm and secure bond between the functional composite formed from the first functional layer and the second functional layer.

[0031] In a further embodiment, the substrate is made of a fiber-reinforced composite material and is already fully consolidated, wherein the matrix material of the fiber-reinforced composite is a thermoset polymer matrix, and wherein the thermoset functional layer is subsequently applied and bonded via remaining reactive groups of the substrate, by dissolving the surface - possibly with an adhesion promoter - and the thermoplastic functional layer is then applied thereon.

[0032] This embodiment focuses particularly on the repair of existing structures, such as the front apron of a train. In the damaged area, another layer of epoxy resin is applied and cured together with a thermoplastic film, making the functional area printable. Bonding the first functional layer to the already cured substrate requires subsequent cross-linking. This usually necessitates dissolving the substrate to create reactive groups. This can be achieved either through the resin itself or by an additional adhesion promoter.

[0033] According to one embodiment, the first functional layer is applied in such a way that the material thickness of the first functional layer is less than 1 mm.

[0034] According to one embodiment, the second functional layer is applied in such a way that the material thickness is less than 10 mm.

[0035] According to one embodiment, the functional element is produced on the second functional layer by printing or spraying the thermoplastic material.

[0036] In this process, the functional element is manufactured directly on the substrate from the thermoplastic material in a second manufacturing process (e.g. 3D printing, overmolding, hot pressing, etc...) to create the hybrid component.

[0037] However, it is also conceivable that the functional element is manufactured separately with regard to its basic guardian geometry and is then joined to the second functional layer in a subsequent joining process.

[0038] The present invention thus achieves a particularly good layer adhesion compared to other methods, such as gluing, by creating an interdiffusion between the thermosetting epoxy resin layer and the thermoplastic functional layer between the first functional layer and the second functional layer, wherein a thermoplastic can subsequently be applied to the thermoplastic functional layer to create or arrange the functional element.

[0039] The invention is explained in more detail using the attached figures as examples. They show: Fig. 1. Perspective view of a hybrid component; Fig. 2. Schematic representation of the production of the substrate with the functional compound.

[0040] Fig. Figure 1 shows a perspective view of a hybrid component 10, which comprises a substrate 11 and a functional element 12 arranged on the substrate 11. In the example in Fig. 1 The functional element 12 is a stringer for stiffening the substrate 11, which is formed from a hybrid metal polymer plate.

[0041] Fig. Figure 2 shows in an embodiment how a substrate 20 can be produced with the functional composite consisting of the first functional layer 21 and the second functional layer 22.

[0042] In the exemplary embodiment of the Fig.2. The substrate 20 can, for example, be a titanium plate. However, it is also conceivable that the substrate 20, made of a fiber composite material, comprises a fiber material and a matrix material embedding the fiber material, whereby the matrix material of the substrate 20 can already be cured or be cured together in a process step with the first functional layer 21 and the second functional layer 22.

[0043] In the area where the functional layers are to be applied to the substrate 20 to form the functional composite, any existing oxide layer in this area is first removed. A primer 21a or an adhesion promoter is then applied, onto which the first functional layer 21, in the form of a film of a thermosetting (epoxy) resin system, is subsequently applied. The second functional layer 22, which consists of or incorporates a thermoplastic material, is then applied to this first functional layer 21, which, in contrast to the second functional layer 22, has a significantly reduced thickness.

[0044] Spacer elements 30 are arranged at the edges, and this structure thus formed is then placed in a heating press with two parallel plates 31 and cured under pressure and heat.

[0045] After consolidation, the substrate 20 has the desired functional composite of the first and second functional layers, whereby a corresponding functional element made of a thermoplastic can now be applied, manufactured or arranged on the second functional layer 22 made of a thermoplastic material.

[0046] This makes it possible to apply functional elements made of a thermoplastic material to substrates that are not thermoplastics and would therefore normally have very poor adhesion. Reference symbol list 10 Hybrid component 11 Substrat 12 Functional element 20 substrate 21a Primer 21 first functional layer / thermoset resin system 22 second functional layer / thermoplastic material 30 spacers 31 Heating press

Claims

A method for producing a hybrid component (10) made from at least two different materials, comprising the following steps: - providing a substrate (11, 20) made of a substrate material onto which at least one functional element (12) is to be applied in a functional area of ​​the substrate (11, 20), - wherein the substrate material is a fiber composite comprising a fiber material and a thermoset matrix material embedding the fiber material, - creating a first functional layer (21) made of a thermoset resin system (21) onto the substrate (11, 20) at least within the functional area of ​​the substrate (11, 20), - wherein the thermoset functional layer (21) is subsequently applied to the already fully consolidated provided substrate, and - wherein the thermoset functional layer (21) is bonded via remaining reactive groups of the substrate.- Applying at least one second functional layer (22) made of a thermoplastic material (22) to the first functional layer (21), wherein the thermosetting resin system (21) and the thermoplastic material (22) are selected such that both form a metallurgical bond after consolidation, and - Applying a thermoplastic material different from the substrate material to this second functional layer (22) produced on the substrate (11, 20) in order to produce the functional element (12) on the substrate (11, 20). Method according to claim 1, characterized in that the first and second functional layer (22) is consolidated before the thermoplastic material for the functional element (12) is applied. Method according to claim 1 or 2, characterized in that the thermosetting resin system (21) is an epoxy resin system and / or that the thermoplastic material (22) is a PEI, PSU, PES or PA. Method according to one of the preceding claims, characterized in that the thermoplastic material of the second functional layer (22) is applied to the first functional layer (21) in the form of a thermoplastic film. Method according to one of the preceding claims, characterized in that the first functional layer (21) is applied such that the material thickness of the first functional layer (21) is less than 1 mm. Method according to one of the preceding claims, characterized in that the second functional layer (22) is applied such that the material thickness is less than 10 mm. Method according to one of the preceding claims, characterized in that the functional element (12) is produced on the second functional layer (22) by printing, injection molding, pressing, welding and / or spraying the thermoplastic material of the functional element (12).

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