Tool and method for manufacturing a laminated fiber-reinforced plastic composite component

Abstract

Tool (102) for producing a laminated fiber-reinforced plastic component (104), the tool (102) comprising a mold section (112) with a mold surface (114) in which the mold section (112) comprises a first thermoplastic material with a first melting temperature and is designed to form and join pre-impregnated fiber semi-finished products in an automated process, wherein the fiber semi-finished products comprise a second thermoplastic material with a second melting temperature as a matrix material and there is a predetermined minimum temperature difference between the first melting temperature and the second melting temperature, and a process for producing a laminated fiber-reinforced plastic component (104) in which pre-impregnated fiber semi-finished products are first automatically heated to a process temperature, placed on the mold surface (114) of such a tool (102) and consolidated under pressure.to create a first layer.

Description

[0001] The invention relates to a tool for producing a fiber-plastic composite component in a lamination process, the tool comprising a molding section with a molding surface. Furthermore, the invention relates to a method for producing a laminated fiber-plastic composite component.

[0002] Document US 2018 / 0229401 A1 relates to a prepared mold with a thermoplastic surface layer polymer coating on the mold surface of the mold or a prepared prepreg with a thermoplastic surface layer polymer coating on the surface of the thermoplastic fiber-reinforced prepreg, which improves the lay-up of the first layer of thermoplastic fiber-reinforced composite prepregs onto molds for prepreg formation or in-situ tape placement. This results in thermoplastic fiber-reinforced composite parts made of a thermoplastic fiber-reinforced thermoplastic composite comprising structural reinforcing fibers with one or more high-performance polymers, and a thermoplastic surface layer polymer coating forming a polymer blend with the high-performance polymers of the thermoplastic fiber-reinforced composite.

[0003] Document US 2018 / 0229401 A1 relates to methods for 3D printing a tool shell for use in manufacturing panels for a transportation structure, such as an automobile, boat, aircraft, or other vehicle or other mechanical structure. A 3D printer may be used to produce a tool shell containing Invar and / or another material for use in molding the panels. A channel may be formed in a 3D-printed tool shell to enable resin infusion, vacuum generation, or heat transfer. Alternatively or additionally, one or more hollow sections may be formed in the 3D-printed tool shell to reduce the weight of the shell.

[0004] Document EP 2 944 454A1 relates to a tool for applying composite material to form a workpiece with a target contour. The tool comprises a support structure. The support structure comprises an elongated member having a longitudinal axis and support plates connected to the elongated member and spaced apart along the longitudinal axis, wherein the elongated member contains a metallic material, and a non-metallic support structure connected to the support plates, wherein the non-metallic support structure comprises a working surface containing a support contour complementary to the target contour.

[0005] From document DE 10 2018 119 751 A1, a method is known for producing a hybrid component, in which a tape substrate layer is produced on a workpiece carrier by at least one tape layer via tape laying, and then a structure is produced on the tape substrate layer by additive application to the tape substrate layer using at least one 3D printing head while the tape substrate layer is arranged on the workpiece holder. Furthermore, from document DE 10 2018 119 751 A1, a system is known for producing a hybrid component, in particular for carrying out such a method, comprising at least one workpiece carrier, at least one tape layer, and at least one 3D printing head, wherein the workpiece carrier is a workpiece carrier for tape laying by the at least one tape layer and for producing a structure on a tape layer.

[0006] The invention is based on the object of structurally and / or functionally improving a tool mentioned above. Furthermore, the invention is based on the object of improving a method mentioned above.

[0007] The object is achieved by a tool having the features of claim 1. Furthermore, the object is achieved by a method having the features of claim 9. Advantageous embodiments and / or further developments are the subject of the subclaims.

[0008] The tool according to the invention is designed for producing a laminated fiber-plastic composite component. The tool can be an open tool. The tool has a mold section. The mold section has a first thermoplastic material with a first melting temperature. The mold section can be made of a first thermoplastic material with a first melting temperature. The mold section can be fiber-reinforced. The mold section can have reinforcing fibers. The first thermoplastic material can serve as a matrix material. The matrix material can surround the reinforcing fibers. The reinforcing fibers can be bonded to the matrix material by adhesive interactions. Examples of reinforcing fibers that can be used include glass fibers, basalt fibers, carbon fibers, and / or aramid fibers.

[0009] The mold section has a mold surface. The mold surface can be open and / or freely accessible. The mold surface can have a shape corresponding to a fiber-plastic composite component to be produced. The mold surface can be contoured spatially and / or in relief. The mold surface can be single-curved and / or multiply-curved, at least in sections. The mold surface can have a predetermined surface quality and / or roughness. For example, the mold surface can have a mean roughness of 20 µm. <R a <70µm.

[0010] The mold section and / or the mold surface can be designed to mold and join pre-impregnated semi-finished fiber products in an automated process, wherein the semi-finished fiber products comprise a second thermoplastic material with a second melting temperature as the matrix material, and the first thermoplastic material and the second thermoplastic material are incompatible. The first thermoplastic material and the second thermoplastic material can be chemically and / or physically incompatible. Incompatibility can arise due to different melting temperatures of the first thermoplastic material and the second thermoplastic material.

[0011] The mold section and / or the mold surface are / is designed to mold and join pre-impregnated semi-finished fiber products in an automated process, wherein the semi-finished fiber products comprise a second thermoplastic material with a second melting temperature as the matrix material, and a predetermined minimum temperature difference exists between the first melting temperature and the second melting temperature. Therefore, the first thermoplastic material with the first melting temperature is selected based on the second thermoplastic material with a second melting temperature. The predetermined minimum temperature difference can be 70°C, in particular 80°C, in particular 90°C, in particular 100°C, in particular 110°C.

[0012] The mold section can comprise an engineering thermoplastic, in particular polyamide (PA), in particular polyamide 6 (PA6), or polyoxymethylene (POM), in particular carbon fiber-filled polyoxymethylene (CF-POM), as the first thermoplastic. The mold section can be designed to mold and join pre-impregnated semi-finished fiber products, wherein the semi-finished fiber products can comprise a high-performance thermoplastic, in particular polyether ketone (PEK), in particular polyaryletherketone (PAEK), in particular low-melting polyaryletherketone (LM-PAEK), as the second thermoplastic.

[0013] The mold section can comprise a high-performance thermoplastic, in particular polyether ketone (PEK), in particular polyaryletherketone (PAEK), in particular low-melting polyaryletherketone (LM-PAEK), as the first thermoplastic. The mold section can be designed to mold and join pre-impregnated semi-finished fiber products, wherein the semi-finished fiber products can comprise an engineering thermoplastic, in particular polyamide (PA), in particular polyamide 6 (PA6), or polyoxymethylene (POM), in particular carbon fiber-filled polyoxymethylene (CF-POM), as the second thermoplastic.

[0014] The molding surface can form a front side of the molding section. The molding section can have a rear side. The molding section can have a predetermined thickness. "Thickness" in this context refers in particular to a distance between the front side and the rear side. The molding section can have an at least approximately constant thickness. The molding section can have a thickness that varies according to a spatial and / or relief-like contouring of the molding surface. The molding section can be self-supporting. The molding section can be designed for arrangement on a support section.

[0015] The tool can have a support section. The support section can have a connecting surface for the mold section. The connecting surface can be designed for a force-fitting, form-fitting, and / or material-fitting connection of the mold section. The connecting surface can be contoured. The connecting surface can be contoured close to the mold section. The connecting surface can be contoured to correspond to a spatial and / or relief-like contour of the mold surface. The support section can have at least one connecting contour. The at least one connecting contour can be undercut. The connecting surface can have a predetermined minimum roughness.

[0016] The mold section can be arranged on the support section. The mold section can be firmly connected to the support section. The mold section can be arranged with its rear side on the support section and / or firmly connected to the support section. The mold section can be manufactured on the support section and / or applied to the support section. The mold section can be manufactured and / or applied using a melting process. The mold section can be manufactured and / or applied using an extrusion-based process. The mold section can be manufactured and / or applied using an additive process. The additive process can also be referred to as a generative process, 3D printing process, or rapid tooling process. In particular, the mold section can be manufactured and / or applied using a fused granular fabrication (FGF) process.In the FGF process, molten plastic granules are extruded layer by layer onto a print bed or the support section to gradually create the mold section. The plastic granules are fed to an extrusion head, which heats them and presses them into a homogeneous, molten plastic mass.

[0017] The method according to the invention is designed for producing a laminated fiber-plastic composite component. First, pre-impregnated semi-finished fiber products are automatically heated to a process temperature, deposited on the molding surface of such a tool, and consolidated under pressure to produce a first layer. The semi-finished fiber products comprise a second thermoplastic with a second melting temperature as the matrix material, and a predetermined minimum temperature difference exists between the first melting temperature and the second melting temperature. The predetermined minimum temperature difference can be 70°C, in particular 80°C, in particular 90°C, in particular 100°C, in particular 110°C.

[0018] The semi-finished fiber products comprise reinforcing fibers and a matrix material. The second thermoplastic serves as the matrix material. The matrix material can surround the reinforcing fibers. The reinforcing fibers can be bonded to the matrix material through adhesive interactions. Examples of reinforcing fibers that can be used are glass fibers, basalt fibers, carbon fibers, and / or aramid fibers. The reinforcing fibers can be continuous fibers. The reinforcing fibers can be arranged unidirectionally. The semi-finished fiber products can comprise a high-performance thermoplastic, in particular polyether ketone (PEK), in particular polyaryletherketone (PAEK), in particular low-melting polyaryletherketone (LM-PAEK) or polyetheretherketone (PEEK), as the second thermoplastic. The semi-finished fiber products can be in strip form. The semi-finished fiber products can also be referred to as tapes.

[0019] A robot with a suitable end effector can be used to heat, deposit, and / or consolidate the semi-finished fiber products. The end effector can comprise a heating device, an unwinding device, and / or a pressing section. The heating device can comprise a heat source, for example a laser. The heat source can be displaceable with respect to a location at which an incoming semi-finished fiber product comes into contact with the forming surface or a preceding layer and / or with respect to a distance from a semi-finished fiber product to be heated. The heat source can be displaceable in a controlled manner. The heat source can be controllable with respect to heat emission.

[0020] The semi-finished fiber products can be formed and bonded using an automated fiber placement (AFP) process. The AFP process is an automated manufacturing process for composite materials in which reinforcing fibers pre-impregnated with a matrix material are heated and compacted. The semi-finished fiber products can be in the form of "tows" or "tapes." The semi-finished fiber products can be deposited and consolidated on the forming surface to create a first layer temporarily bonded to the forming surface.

[0021] A process temperature, a process temperature profile, a consolidation pressure, and / or a consolidation pressure profile can be controlled with respect to a temporary bond between the mold surface and the first layer. The process temperature, the process temperature profile, the consolidation pressure, and the consolidation pressure profile can be process parameters of the method. The process temperature can be in a softening range and / or flow range of the first thermoplastic and / or the second thermoplastic. The method can have further process parameters and / or be influenced by further process parameters. "Control" refers in particular to control by means of closed-loop or closed-loop control.

[0022] “With a view to a temporary bond” means in particular that the process temperature, the process temperature profile, the consolidation pressure and / or the consolidation pressure profile are controlled in order to adjust the bond with regard to properties relevant for a temporary bond between the mold surface and the first layer. In particular, on the one hand, the first layer should be connected to the mold surface with sufficient force and / or time, and on the other hand, demolding of the laminated fiber-plastic composite component should be enabled. Furthermore, the first layer should be able to be removed from the mold surface with as little residue as possible when demolding the laminated fiber-plastic composite component. Furthermore, a surface structure, in particular a roughness, of the mold surface should be retained as far as possible.

[0023] One property of the bond between the molding surface and the first layer that can be adjusted is the strength of the bond. Peel strength or peel adhesion can be used to assess and / or adjust the strength. Peel adhesion or peel force is defined as the force required to pull the first layer and / or the fiber-reinforced plastic composite component away from the molding surface. Tack, cohesion, and / or adhesion of the first thermoplastic and / or the second thermoplastic can also be used to assess and / or adjust the strength.

[0024] Subsequently, pre-impregnated semi-finished fiber products can be automatically heated to a process temperature, deposited on a previous layer, and consolidated under pressure to produce at least one additional layer. A process temperature, a process temperature profile, a consolidation pressure, and / or a consolidation pressure profile can be controlled to ensure a permanent bond between the layers.

[0025] "With a view to a permanent bond" means, in particular, that the process temperature, the process temperature profile, the consolidation pressure, and / or the consolidation pressure profile are controlled in order to adjust the bond with regard to properties relevant for a permanent bond between the first layer and the at least one further layer. In particular, the first layer and the at least one further layer should be permanently and firmly bonded to one another in accordance with the requirements of the fiber-reinforced plastic composite component to be manufactured or to be manufactured.

[0026] When producing the first layer on the one hand and when producing the at least one further layer on the other hand, the process temperatures, the process temperature profiles, the consolidation pressures and / or the consolidation pressure profiles can be controlled differently, in particular each adapted to producing a temporary connection or producing a permanent connection.

[0027] The first layer can be produced at a lower process temperature, a lower process temperature profile, a lower consolidation pressure, and / or a lower consolidation pressure profile than the at least one further layer. The at least one further layer can be produced at a higher process temperature, a higher process temperature profile, a higher consolidation pressure, and / or a higher consolidation pressure profile than the first layer.

[0028] The first layer and the at least one further layer can form a fully laminated fiber-plastic composite component. The first layer and the at least one further layer can form a first cover layer of a sandwich fiber-plastic composite component. The method can comprise further steps. The fiber-plastic composite component can be manufactured in a sandwich construction. The method can comprise steps for producing a component core. The method can comprise steps for producing a second cover layer.

[0029] In summary and in other words, the invention thus results, among other things, in the use of a thermoplastic mold surface in combination with an automated fiber placement material (AFP material) with widely differing melting temperatures to produce first-layer adhesion during automated fiber placement.

[0030] For example, a tool with a polyamide 6 forming surface can be used to apply continuous fiber-reinforced LM-PAEK tapes as pre-impregnated semi-finished products in an in-situ AFP process to form a component. The tool material PA6 enables good adhesion of the component to the mold during production and good demoldability after production due to the incompatibility of the plastics. As a thermoplastic material, PA6 can be processed into molds using extrusion-based manufacturing methods, such as 3D printing. This allows complex shapes to be produced quickly and with low material costs. The strength of the bond between the tapes and the mold can be adjusted by adjusting the process parameters of the AFP process.

[0031] A tool may have, at least on its surface, a thermoplastic, also with fiber reinforcement, which is applied by means of a technical melting process whose melting temperature differs significantly from that of an AFP-applied material.

[0032] The described first layer concept can also be applied by automatically applying a prepared core made of a suitable material, such as a base plate / blocks close to the mold contour, around a final mold contour layer, provided that the core is prepared with appropriate connection options for the plastic coating.

[0033] The tool and / or process is / are particularly applicable as rapid tooling technology for AFP processes, in toolmaking for AFP processes, in the prototype construction of fiber-reinforced plastic components (FRP components) in the AFP process or in the small-series production of FRP components. The first-layer technology can be used in preforming production as preforming tooling for the construction of fiber and blank stacks of fiber-reinforced tapes in 2D and 3D stacks, for example as a precursor to composite components. The process concept converges as a technical component or mold and can, for example, represent a thermoplastic, reusable "print bed" or "substrate" for AFP and organic sheet stacking machines made of low / high-melting plastic, e.g. PA6 sheet in combination with PAEK tapes.

[0034] The invention reduces expenditure such as time and / or cost. Material requirements are reduced. Component quality is improved. Flexibility is increased. Process reliability is increased. Adjustment of a connection with regard to properties relevant for a temporary connection between a mold surface and a first layer is made possible. On the one hand, the first layer is connected to the mold surface with sufficient force and / or time, and on the other hand, demolding of the laminated fiber-plastic composite component is made possible. When the laminated fiber-plastic composite component is demolded, the first layer can be removed from the mold surface at least almost residue-free. Wear of a surface structure, in particular of roughness, is reduced or avoided. Fiber-plastic composite components with complex curved surfaces can be manufactured efficiently.

[0035] In the following, embodiments of the invention are described in more detail with reference to figures, which show schematically and by way of example: Fig. 1 a process chain that combines the production of a tool in an FGF process and the production of a laminated fiber-plastic composite component in an AFP process.

[0036] Fig. 1 shows a process chain 100 that combines the production of a tool 102 and the production of a laminated fiber-reinforced plastic composite component 104. The fiber-reinforced plastic composite component 104 is manufactured in a sandwich construction and has a first cover layer 106, a component core 108, and a second cover layer 110.

[0037] The tool 102 has a mold section 112. The mold section 112 is manufactured from a first thermoplastic material in an FGF process and has a mold surface 114. The manufacture of the tool 102 is described in Fig. 1 designated 116.

[0038] The first cover layer 106 is manufactured as a laminate with a first layer and further layers of band-shaped, pre-impregnated semi-finished fiber products, referred to as tape. The semi-finished fiber products used for the first cover layer 106 comprise carbon fibers as reinforcing fibers and low-melting polyaryletherketone (LM-PAEK) with a melting point of 305°C as the matrix material or second thermoplastic. Based on this, polyamide 6 (PA6) is selected as the first thermoplastic for the mold section 112.

[0039] To produce the fiber-plastic composite component 104, the first cover layer 106 is first produced using an AFP process. For this purpose, semi-finished fiber products are heated to a process temperature, placed on the molding surface 114, and consolidated under pressure to produce the first layer of the first cover layer 106. A process temperature, a process temperature profile, a consolidation pressure, and / or a consolidation pressure profile are controlled with regard to a temporary connection between the molding surface 114 and the first layer in such a way that the first layer is sufficiently connected to the molding surface 114 in terms of force and / or time, demolding of the laminated fiber-plastic composite component 104 is enabled, the first layer can be removed from the molding surface 114 without leaving any residue during demolding of the laminated fiber-plastic composite component 104, and the roughness of the molding surface 114 is maintained.After producing the first layer, a further layer of the first cover layer 106 is produced by heating semi-finished fiber products to a process temperature, depositing them on the first layer, and consolidating them under pressure. A process temperature, a process temperature profile, a consolidation pressure, and / or a consolidation pressure profile are controlled with a view to a permanent bond between the first layer and the further layers in such a way that a permanently strong bond is ensured in accordance with the requirements of the fiber-plastic composite component to be produced or being produced. Accordingly, further layers are produced until the laminated first cover layer 106 is completed. The production of the first cover layer 106 is described in . Fig. 1 designated 118.

[0040] Subsequently, the component core 108 is manufactured as a honeycomb structure on the first cover layer 106 using an FGF process. The production of the component core 108 is described in Fig. 1 with 120. Subsequently, the second cover layer 110 is produced on the component core 108 using an AFP process. The production of the second cover layer 110 is shown in Fig. 1 designated 122.

[0041] Finally, the fiber-reinforced plastic composite component 104 is removed from the tool 102, with the first cover layer 106 separating smoothly from the mold surface 114. The fiber-reinforced plastic composite component 104 has the desired surface structure on its cover layer 104, and the mold surface 114 is available for the production of further fiber-reinforced plastic composite components.

[0042] "May" refers in particular to optional features of the invention. Accordingly, there are also further developments and / or embodiments of the invention that additionally or alternatively comprise the respective feature(s).

[0043] If necessary, features can also be selected from the combinations of features disclosed in the description and used alone or in combination with other features to define the subject matter of the claim, dissolving any structural and / or functional connection that may exist between the features. Reference symbol 100 Process chain 102 tools 104 Fiber-reinforced plastic composite component 106 first top layer 108 component core 110 second top layer 112 mold section 114 Form surface 116 Making the tool 118 Producing the first top layer 120 Manufacturing the component core 122 Producing the second cover layer QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2018 / 0229401 A1 [0002, 0003] EP 2 944 454A1

[0004] DE 10 2018 119 751 A1

[0005]

Claims

[1] Tool (102) for producing a laminated fiber-plastic composite component (104), the tool (102) comprising a mold section (112) with a mold surface (114), characterized by in that the molding section (112) comprises a first thermoplastic material having a first melting temperature and is designed to mold and join pre-impregnated fiber semi-finished products in an automated process, wherein the fiber semi-finished products comprise a second thermoplastic material having a second melting temperature as matrix material and there is a predetermined minimum temperature difference between the first melting temperature and the second melting temperature. [2] Tool (102) according to claim 1, characterized by that the specified minimum differential temperature is 70°C, in particular 80°C, in particular 90°C, in particular 100°C, in particular 110°C. [3] Tool (102) according to at least one of the preceding claims, characterized bythat the mold section (112) is produced in a melting process. [4] Tool (102) according to at least one of the preceding claims, characterized by that the tool (102) has a support section and the mold section (112) is firmly connected to the support section. [5] Tool (102) according to claim 4, characterized by that the support section has a connecting surface for the mold section (112) and the connecting surface is contoured close to the mold section and / or is designed for the force-fitting, form-fitting and / or material-fitting connection of the mold section (112). [6] Tool (102) according to at least one of the preceding claims, characterized byin that the mold section (112) has an engineering thermoplastic, in particular polyamide (PA) or polyoxymethylene (POM), as the first thermoplastic material and is designed to mold and join pre-impregnated semi-finished fiber products, wherein the semi-finished fiber products have a high-performance thermoplastic, in particular polyether ketone (PEK), in particular polyaryletherketone (PAEK), in particular low-melting polyaryletherketone (LM-PAEK), as the second thermoplastic material. [7] Tool (102) according to at least one of the preceding claims, characterized by that the molded section (112) is manufactured and / or applied in an extrusion-based additive process. [8] Tool (102) according to at least one of the preceding claims, characterized by that the mold section (112) is fiber-reinforced. [9] Method for producing a laminated fiber-plastic composite component (104), characterized bythat initially pre-impregnated semi-finished fiber products are automatically heated to a process temperature, placed on the molding surface (114) of a tool (102) according to at least one of the preceding claims and consolidated under pressure in order to produce a first layer, wherein the semi-finished fiber products have a second thermoplastic material with a second melting temperature as matrix material and there is a predetermined minimum difference temperature between the first melting temperature and the second melting temperature. [10] Method according to claim 9, characterized by that the specified minimum differential temperature is 70°C, in particular 80°C, in particular 90°C, in particular 100°C, in particular 110°C. [11] Method according to at least one of claims 9 to 10, characterized bythat a process temperature, a process temperature profile, a consolidation pressure and / or a consolidation pressure profile are / is controlled with regard to a temporary connection between the mold surface (114) and the first layer. [12] Method according to at least one of claims 9 to 11, characterized by that subsequently pre-impregnated semi-finished fiber products are automatically heated to a process temperature, deposited on a previous layer and consolidated under pressure in order to produce at least one further layer, wherein a process temperature, a process temperature profile, a consolidation pressure and / or a consolidation pressure profile are / is controlled with regard to a permanent connection between the layers. [13] Method according to at least one of claims 11 to 12, characterized bythat during the production of the first layer on the one hand and during the production of the at least one further layer on the other hand, the process temperatures, the process temperature profiles, the consolidation pressures and / or the consolidation pressure profiles are controlled differently. [14] Method according to at least one of claims 11 to 13, characterized by that the first layer is produced at a lower process temperature, a lower process temperature profile, a lower consolidation pressure and / or a lower consolidation pressure profile than the at least one further layer.

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