Automated processing of high temperature stable closed cell rigid foams.

Abstract

The present invention discloses a method for automated manufacturing of lightweight components. The method includes providing a high-temperature stable, closed-cell, rigid foam, providing a fiber reinforcement material, and automatically applying the fiber reinforcement material to the high-temperature stable, closed-cell, rigid foam. The high-temperature stable, closed-cell, rigid foam has a Tg of 100°C or greater, preferably 180°C or greater. The lightweight components are preferably aviation and aerospace components. Additionally, the present invention includes a production line for carrying out the automated method for manufacturing lightweight components.

Description

[Technical Field]

[0001] The present invention relates to an automated method for processing high-temperature stable closed-cell rigid rigid foams, in particular a method for producing a composite system having at least one outer layer and a high-temperature stable closed-cell rigid rigid foam as a core layer, the composite system being suitable for lightweight construction. The present invention further relates to a production plant for the automated production of lightweight components by processing high-temperature stable closed-cell rigid rigid foams.

[0002] Background technology In the lightweight construction sector, especially in aviation and aerospace technology, it is important to use particularly light and robust materials with low density and surfaces that are stable to high and low temperatures, ranging from approximately -55 °C to 180 °C, in order to meet the requirements of the flying object and at the same time keep the flying object in the air with minimal energy consumption. In the field of aviation and aerospace technology, it is advantageous if the material can withstand high bending and compressive forces.

[0003] To achieve this goal, similar to rigid foams, honeycombs are preferred for the manufacture of sandwich structures, as their structural biological properties are adapted from beehives. They can be manufactured from paperboard, resin-impregnated paper, fiber plastics, or thin aluminum foil. In the aerospace industry, metal honeycombs, such as aluminum honeycombs, are preferred. In aviation, it is preferred to use resin-impregnated paper or boards that cure at high temperatures, so that honeycomb structures are stable at temperatures between 60 and 180°C.

[0004] Sandwich elements with a honeycomb core (also called honeycomb elements) are three-layer composite structures in a sandwich design consisting of two weight-bearing outer layers and a honeycomb-shaped support core. The outer layers can be made of plate, plastic, fiber composite material, or sheet metal. Various material combinations for the support core and outer layers are possible, and the support core and outer layers are generally bonded to each other.

[0005] Because production speeds in the aviation and aerospace industries are generally low, corresponding manufacturing technologies, such as honeycomb prepreg manufacturing (the production of honeycomb elements with pre-impregnated fibers), are based on manual process steps. However, it would be advantageous to automate the manufacturing process of sandwich structures or modules required for air vehicles, such as aircraft or spacecraft, in order to shorten manufacturing times and process steps, increase efficiency, produce consistent quality, save production costs, and improve environmental performance by reducing material waste and consumption. Furthermore, the use of innovative manufacturing technologies can enable new approaches to construction and load management.

[0006] For honeycomb materials, first attempts are being made to replace part of the process with automated manufacturing technology, Automated Fiber Placement (AFP), in the production of helicopter side panels.

[0007] However, due to the high flexibility and instability of honeycomb structures and their pores, it has not been possible to automate both the compression of honeycomb structures to obtain a honeycomb sandwich structure and the entire processing operation for producing the sandwich structure, starting, for example, with cutting the honeycomb material and repairing the edge fringes, cutting the fabric, laying the lower outer layer of plies, consolidating the core by placing it on the honeycomb material, laying the upper outer layer, compressing the structure, and impregnating it with resin. Furthermore, automating the handling of honeycomb structures is difficult because the honeycomb structure is difficult to grip due to its high flexibility, and the material does not remain in place after laying. Therefore, AFP has only been possible on honeycomb materials that have already been processed into sandwich elements, and AFP has been possible on the outer layers of the honeycomb structure.

[0008] Due to the openness of honeycomb structures, it is not possible to handle the material with a vacuum manipulator. Vacuum manipulators allow for particularly gentle handling of workpieces, a compact and space-saving system design, and a top-down grip that allows for gap-free placement of the material. Vacuum manipulators hold the workpiece to be handled on their suction cups by means of reduced pressure. The object needs a smooth, continuous surface so that air can be sucked in and the manipulator can adhere to it. Because honeycomb structures have open pores, it is not possible to generate the reduced pressure that would allow a vacuum manipulator to hold and manipulate honeycomb material.

[0009] Other manipulators similarly fail to solve the problem of automated handling of honeycomb structures.

[0010] Mechanical manipulators are most commonly used in robotics. They can be pneumatically, hydraulically, or electrically actuated. This type of device allows for precise movement at a relatively low cost. Examples of mechanical manipulators are parallel, angular, radial, and three-point grippers. Due to the high flexibility of honeycomb structures, it is difficult to pick up the material, as the structure will bend when picked up. Similarly, it is difficult to precisely position the structure with a mechanical manipulator without damaging or shifting the base on which the structure is placed.

[0011] Mechanical manipulators are distinguished between permanent magnet manipulators and electromagnetic manipulators. With permanent magnet manipulators, the pickup force is provided by a permanent magnet, so the workpiece must be "detached" from the manipulator. Electromagnetic manipulators are powered by a DC current that generates the necessary magnetic field. Ferromagnetic workpieces are picked up and released by switching the power on and off. Magnetic pickup techniques share the same drawbacks with honeycomb structures as mechanical manipulators. Furthermore, before a non-magnetic honeycomb structure can be moved with a magnetic manipulator, the opposing magnet of the manipulator must be applied to the material. This is difficult because honeycomb structures have open holes, and the fastening means can only be applied to the thin end of the honeycomb structure's support wall, not the entire area, which can cause problems with magnet adhesion. Even if the honeycomb structure is made of magnetic material, hollow honeycombs can cause pickup problems because the magnetic interaction between the honeycomb structure and the manipulator may be too weak.

[0012] For sensitive, residue-free pickup, adhesive manipulators can also be used. This technology is based on the principle of adhesion, using intermolecular van der Waals forces for handling. The gripping surface of the gripper is equipped with microscopic hairs that develop shear adhesion when pressure is applied to the surface. This component-friendly adhesive technology does not require compressed air, vacuum, or power, so initial use is relatively low in complexity. However, picking up honeycomb structures with adhesive manipulators is not possible because the cohesive surface area due to the honeycomb structure's openings is too small to establish sufficient interaction via van der Waals forces.

[0013] Honeycomb structures have the additional disadvantage that, due to their structure, it is difficult to position and drape the upper and lower outer layers. The layers can only be applied to the thin edges of the honeycomb support walls, so the fixing material cannot be fixed over the entire area, but can only be fixed at certain points, which makes it easy to detach. Also, since the fixing material cannot be applied to the entire surface area of ​​the honeycomb structure, air bubbles and other irregularities are easily formed in the layer material.

[0014] Furthermore, applying the adhesive means in an automated manner is very demanding, since in the case of automated application the bonding means is not specifically applied to the edges of the honeycomb structure, but is distributed over the entire open area, which has the drawback that, firstly, the material penetrates into the honeycomb structure, thus adding unnecessary weight to the honeycomb structure, and secondly, the required bonding strength of the bonding means may not be achieved, since the edges are not specifically provided with the bonding means.

[0015] A further drawback is that the honeycomb sandwich structure is unstable due to the fraying of the honeycomb structure and the hexagonal cavities in the honeycomb material, so the connecting elements and / or other force-introducing elements cannot be automatically installed in a simple, fixed manner after drilling and / or inserting into the honeycomb sandwich structure. If holes are drilled, they must be backfilled in a controlled manner, the connecting elements and / or other force-introducing elements must be fitted at the exact site of material penetration, and the connecting elements and / or other force-introducing elements must be fixed. This increases the weight of the honeycomb sandwich structure and increases manufacturing costs.

[0016] An additional factor is that honeycomb material, due to its hexagonal honeycomb structure, frays when cut at the edges and must therefore be stabilized according to the individual fray pattern, which complicates the automation process and involves additional work as well as increased weight and manufacturing costs.

[0017] All these drawbacks make automated handling complicated or, to date, impossible.

[0018] The article "Holding out for a hero!" by Mike Richardson, in Composites in Manufacturing, May 19, 2020, available from https: / / www.composites.media / holding-out-for-a-hero / category / features, describes the automated manufacturing of sandwich-engineered Rohacell HERO foam fiber composites. Product information "ROHACELL® HERO" (Evonik, April 2022, available from https: / / performance-foams.evonik.com / en / products-and-solutions / rohacell / rohacell-hero-170036.html) describes the technical properties of ROHACELL® HERO. The product information, "ROHACELL® HERO - The Core Material for Aircraft Structures" (Evonik, June 2022, available at https: / / performance-foams.evonik.com / en / products-and-solutions / rohacell / rohacell-hero-170036.html), concerns testing of sandwich composite aircraft components made with ROHACELL® HERO.

[0019] Due to increasing production rates in the aviation and aerospace industries, there is a need for automated handling and manufacturing methods for components made from lightweight building materials, as well as manufacturing lines for implementing such methods.

[0020] Summary of the Invention The problem that prior art product manufacturing processes cannot meet practical needs is solved according to the present invention by the method and manufacturing line according to the present claims.

[0021] It has surprisingly been found, particularly in aviation and aerospace technology, that high-temperature stable, closed-cell, rigid, hard foams can be handled and processed in an automated manner by the method according to the invention.

[0022] The method according to the invention has fast and efficient manufacturing steps. Furthermore, the manufactured lightweight components are highly reproducible and of consistent quality. Automation allows for the production of more lightweight components in a shorter time. The method improves the ecological footprint by at least 20% compared to conventional manual methods. Manufacturing waste can be reduced by up to 50%. Furthermore, cost savings of up to 40% can be achieved. [Brief explanation of the drawings]

[0023] [Figure 1] 1 shows a comparison of the process times of the method according to the invention for the automated manufacture of lightweight components with a method for the manual manufacture of lightweight components;

[0024] MODE FOR CARRYING OUT THE INVENTION The section headings below are merely for ease of reading and should not be construed as separating embodiments from one another.

[0025] definition Unless otherwise defined, the terms used herein have the definitions set forth below.

[0026] Firstly, it is expressly pointed out that in the context of this patent application, indefinite articles and numerical descriptions such as "one", "two", etc. are to be understood generally as describing "at least", i.e. "at least one...", "at least two...", etc., unless this is expressly clear from the respective context or is obvious to a person skilled in the art or is necessary for technical reasons where this could mean "exactly one...", "exactly two...", etc.

[0027] In the context of this patent application, the expression "in particular" should always be understood as introducing optional preferred features. It should not be understood as meaning "and which" or "that is to say."

[0028] The expression "closed pore foam" as used herein relates to a foam having closed pores to the extent of nearly 100%, preferably 50-100%, 75-100%, 80-100%, 85-100%, 90-100%, 95-100%, 99-100%, more preferably 100%. The expression "closed pore" should be understood to mean that the pores of the foam are closed.

[0029] This has the advantage that a vacuum can be applied to the foam. Furthermore, penetration of materials, e.g., molding compounds, is reduced, which offers the advantage of producing lighter building materials, e.g., sandwich structures.

[0030] As used herein, the term "hard" refers to a material that is neither soft nor elastic, but rather is firm, durable, and does not yield very much.

[0031] The term "rigid" as used herein refers to a bending stiff, non-yielding, non-flexible, statically inelastic material having a modulus of elasticity greater than 0.01 GPa.

[0032] The term "prepreg" as used herein refers to a fabric pre-impregnated with a thermosetting or thermoplastic resin. The resin may be applied to the fabric in the form of a powder, melt, solution, or aqueous dispersion along with the fabric material.

[0033] The term "resin transfer molding" (RTM) as used herein refers to a method for producing preforms, particularly sandwich structures. At the start of the cycle, the molding compound is present in the antechamber. First, the material to be processed into the preform is placed in the mold formed by the first and second molds, and the mold is closed. The molding compound, particularly in the form of a resin, is injected or infiltrated into the material present in the closed mold, preferably using high pressure, and then vulcanized in the closed mold under pressure and temperature for a specific period of time. The molding compound is injected into the mold from the generally heated antechamber through at least one distributor channel, preferably multiple distributor channels.

[0034] When only one distributor channel is used to inject the molding compound into the mold, this is called single-point injection. With single-point injection, the flow front can trap air, which leads to cavities. When the molding compound is injected into the mold through multiple distributor channels, this is called multi-point injection. The mold can fill with resin more quickly through multiple injection points. Arranging multiple injection points can prevent air trapping. In linear injection, injection occurs in a line rather than at a single point on the mold edge. This can be advantageous for components with a high length ratio, as the flow only needs to traverse a shorter edge length. In channel injection, resin is injected through a wide channel above or below the material being molded into the preform. In cascade injection, multiple injection sites are arranged in the direction of the flow front to maintain a low pressure gradient. However, the injection conduits must be opened and closed along the flow front.

[0035] Injection can be performed using a piston. Depending on the position of the injection piston, there are three basic methods: the bottom piston method (two-piston method) where the injection piston is located below the mold, the top piston method (one-piston method) where the injection piston is located above the mold, and a horizontal injection piston, generally with a screw pre-plasticization unit. The time it takes to vulcanize the material or molding compound depends on various factors, such as the molding compound, optional fillers, processing pressure, and temperature. After vulcanization, the mold can be opened. The previously introduced molding compound hardens and becomes solid, and the material in the mold is called a preform. It can then be demolded from the mold. Any excess molding compound remaining in the antechamber, also known as residual cake, is removed and replaced with new molding compound before the start of a new cycle. The mold is then cleaned, and a new cycle can begin.

[0036] To avoid air entrapment during the injection operation, the mold cavity is typically evacuated using a vacuum.

[0037] The advantages of the RTM process are that the preforms are produced with high build quality, their surfaces are smooth and aerodynamic on all sides, and a large number of items can be produced.

[0038] The terms "vacuum infusion" and "vacuum injection" refer to different processes for producing preforms similar to those used in RTM. In contrast to RTM, vacuum infusion and vacuum injection use only one mold, into which the material to be processed into the preform is applied. A vacuum film is placed over the mold, and then the molding compound is either poured (vacuum infusion) or injected into a single-shell mold closed by the vacuum film (vacuum injection). In vacuum infusion or vacuum injection, the resin has much lower fluidity than in RTM. The vacuum is preferably generated at approximately 0.6-0.8 bar. The finished part has a smooth surface on only one side, in contrast to RTM, which uses a closed mold. Vacuum infusion and vacuum injection are cheaper due to the lower cost of the mold.

[0039] The molds used in the RTM, vacuum infusion and vacuum injection processes may be full molds, flexible molds, mixed molds (eg, pipe blow molding RTM) or duplex molds.

[0040] The molding compounds used in RTM, vacuum infusion, and vacuum injection processes are preferably reactive resins with low viscosity. This keeps the flow resistance during traversal of the mold low, reducing the pressure differential required for filling. Reactive resins for RTM processes can be specific injection resins consisting of resin and hardener components. Low-reactivity resin systems may be mixed before injection. When high-reactivity resin systems are used, the resin and hardener can be mixed directly in the injection line or mold for the first time. This allows for shorter cycle times. The process of directly mixing the injection resin components before injection is called RIM (reaction injection molding). The molding compounds used can be formaldehyde resins, preferably phenol-formaldehyde (PF) and melamine-formaldehyde (MF), and reactive resins, preferably unsaturated polyester resins (UP) and epoxy resins (EP), containing small filler particles and elastomers.

[0041] The term "autoclave molding" is understood herein to mean a method of pressing fiber composite materials under pressure, including fiber-reinforced materials and high-temperature-stable, closed-pore, rigid rigid foams. For this purpose, a hermetically closable pressure vessel is used for the heat treatment of materials in the high-pressure range, comprising a first mold and a second mold, which can be hermetically sealed. In autoclave molding, pressures of up to 10 bar and temperatures of up to 400°C are typically generated. An internal pressure of at least 8 bar and temperatures of 60-250°C are preferably applied. Pressure is applied using a compressor, preferably a pressure storage device. In autoclave molding, a fiber-reinforced material as the lower outer layer, followed by a high-temperature-stable, closed-pore, rigid rigid foam, and finally a further fiber-reinforced material as the upper outer layer, are applied to the first mold part, after which the two mold parts are hermetically sealed to form the mold. The high pressure compresses the individual materials, resulting in a preform in the form of a sandwich structure for the fiber composite component. The mold is preferably completely freed of excess air. The fiber composite formed by combining a woven fabric impregnated with a synthetic resin, preferably an epoxy resin, with a high-temperature stable closed-cell rigid foam is even more preferably cured at a temperature of 100-250°C for a period of 5 minutes to several hours, depending on the resin and curing agent. After curing, the mold is cooled to an internal temperature of less than 40°C and transformed into an open position so that the fiber composite component or preform can be removed.

[0042] The term "sheet molding compound" (SMC) refers to a paste-like molding compound in sheet form composed of thermosetting reactive resins and glass fibers for producing fiber-reinforced polymer composites in the form of sandwich structures. In SMC, all necessary components are thoroughly premixed and can be applied into a mold or into a high-temperature stable, closed-cell rigid foam. Fiber composites that are not supplied as sheets are also called bulk molding compounds (BMC).

[0043] The term "automated tape placement" (ATP), as used herein, refers to an automated method of fiber reinforcement in materials. Wide unidirectional tapes are automatically applied to materials, particularly high-temperature stable, closed-cell, rigid, hard foams, using a loaded roller system that articulates differently depending on the complexity of the material being produced. ATP essentially corresponds to the manual application of unidirectionally aligned reinforcing fiber tapes, but at higher speeds, with larger parts, and better process control. An end effector handles the tape and uses heat and pressure to deposit it onto a surface. ATP systems have precise control of tape initiation, location, and alignment, allowing for the addition of more complex reinforcements than simply adding additional plies to a material or laminate.

[0044] For the manufacture of large parts, such as the skin of an aircraft wing, a single wide tape is generally used, up to 300 mm wide, preferably up to 150 mm wide.

[0045] This technique is advantageous because it allows for the precise laying of continuous fiber tapes to produce multi-layer composite products that generally have considerable strength.

[0046] The term "automated fiber placement" (AFP), as used herein, also refers to an automated method of fiber reinforcement of materials. AFP is also known as advanced fiber placement. Reinforcement materials, such as high-temperature stable, closed-cell rigid rigid foam, provide the same or higher strength and lower weight compared to metals. As with ATP, AFP machines not only automatically lay fiber reinforcement onto molds or mandrels, but also onto preforms or sandwich structures containing high-temperature stable, closed-cell rigid rigid foam, or directly onto high-temperature stable, closed-cell rigid rigid foam, using multiple, separate, thin strands of thermosetting or thermoplastic pre-impregnated material to produce composites.

[0047] AFP uses multiple thin fibers with widths of 10-16 mm, preferably 3-13 mm, and more preferably 8 mm. Because of the smaller fiber width compared to ATP tapes, AFP allows for more complex geometries than ATP. Furthermore, AFP machines can cover surfaces with a higher degree of curvature than ATP.

[0048] AFP is an automated method for producing fiber-reinforced materials in which synthetic resin-preimpregnated non-metallic fibers are heated and compressed, typically on a complex mandrel. The fibers are generally introduced in the form of a "tow." A tow is a bundle of epoxy-resin-impregnated carbon fibers, typically present on a spool, approximately 12.7 mm wide and 0.13 mm thick. Fiber placement machines (FPMs) typically have a capacity of 12 to 32 fiber bundles, or a corresponding web width of 3.81 cm to 10.16 mm if all fiber bundles are simultaneously placed in the web. The tape is fed into the heated compression roll of the FPM head and is then placed across the material surface of the web by robotic mechanical movement. The web is preferably laid at 0°, +45°, -45°, and 90° orientations to combine to form a ply with good properties in all directions. Fiber placement machines are generally rated by weight per unit time.

[0049] AFP increases speed and precision in the production of highly developed fiber-reinforced materials. This technique also allows for better precision and higher lay-down rates compared to empirical laminators. AFP allows for more complex geometries than ATP, but does not achieve the same lay-down rates as ATP. AFP can be used to produce complex structures that cannot be produced by other automated methods.

[0050] AFP systems are generally tailored to a specific use, but they all consist of a head with a compression roll, a fiber feeding system, a robotic mechanism to hold the head, and a human-machine interface.

[0051] AFP machines use a tape laying head to lay down multiple individual narrow webs of tape to build a product. The tape is fed to the head through a tape supply system that houses multiple spools of tape. The spools preferably have a tape capacity of approximately 1000 meters per spool.

[0052] The tape is precisely laid by the AFP machine according to a computer program defined to obtain optimal alignment of the fibers based on the expected operating loads of the part from which the final product will be manufactured. The tape laying head is connected to a robot that guides the head into the correct position during the process.

[0053] In recent years, significant progress has been made in optimizing AFP layup using simulation software. Simulation software is beginning to replace simpler programming software supplied by machine manufacturers. As a result, AFP machines can be selected independently of any software. As with computer numerical control (CNC) for machining tools such as drills, lathes, and milling machines, it is now possible to design a part using AFP and simulate its manufacturing offline, for example, through software simulation of the AFP machine. Software tools for composite construction allow AFP manufacturing requirements to be considered even early in the product development cycle and therefore directly applicable to the final manufacturing process.

[0054] Compared to other methods for producing fiber-reinforced materials, the use of AFP has many advantages and disadvantages. The advantages of AFP are the automation of the process, the repeatability and reproducibility of the production, and the low loss of material. The disadvantages are the relatively slow construction speed and the high cost of the equipment, due to the very thin fibers.

[0055] The materials used for AFP and ATP are thermosetting and thermoplastic fiber / tape materials. A thermosetting resin, preferably an epoxide, is used as the polymer matrix of the fiber / tape to bond the fibers together during the manufacturing process. The use of a thermosetting resin has many advantages, including easier fiber impregnation, fewer compatibility issues between the thermosetting resin and the fiber / tape, better adhesion to the fiber, and greater thermal stability, especially in the case of epoxides.

[0056] Thermoplastic resins, preferably polycaprolactam and polypropylene, have additional advantages: they are cheaper than thermosets, have higher impact resistance, have better corrosion resistance than thermosets, offer greater design flexibility, allow for shorter cycle times, allow for more reliable handling of raw materials, allow for long-term storage of raw materials, have better control of chemistry, and are more recyclable.

[0057] The fibers used in the AFP or ATP may be natural textile or synthetic, metal, carbon, glass, polymer or aramid fibers.

[0058] The term "fabric" as used herein refers to a reinforcing fabric that stabilizes the core structure and makes it dimensionally stable after infiltration with the molding compound.

[0059] Aspects of the present invention 1.Follow these steps: a) providing a high temperature stable closed pore rigid hard foam; b) providing a fiber reinforcement material; c) automatically applying a fiber reinforcement material to a high temperature stable closed pore rigid hard foam; Including, The high temperature stable closed cell rigid foam has a Tg of 100°C or more, preferably 130°C or more, more preferably 180°C or more. Methods for automated manufacturing of lightweight components.

[0060] 2. The method of embodiment 1, wherein the lightweight components are aviation and aerospace components.

[0061] 3.Following steps, c1) applying a fiber reinforcement material by a first manipulator; c2) laying a fiber reinforced material into the first mold as a first outer layer by a first manipulator; c3) receiving, by the first manipulator or the second manipulator, a high temperature stable closed pore rigid hard foam; c4) applying a high temperature stable closed pore rigid hard foam to the first outer layer by the first manipulator or the second manipulator; Optionally, c5) receiving the fiber reinforced material by the first or second manipulator and laying the fiber reinforced material by the first or second manipulator into the second mold part as a second outer layer or onto the high temperature stable closed pore rigid hard foam; c6) compressing the fiber reinforced material and the high temperature stable closed pore rigid foam to create a sandwich structure comprised of a fiber reinforced high temperature stable closed pore rigid foam, the sandwich structure comprising a first outer layer, a high temperature stable closed pore rigid foam, and optionally a second outer layer, the first and second outer layers forming upper and lower outer layers surrounding the high temperature stable closed pore rigid foam; 3. The method of any of embodiments 1 and 2, comprising:

[0062] 4. The method of embodiment 3, wherein performing step c1) is preceded by automatic cutting to size of the fiber reinforced material.

[0063] 5. The method of any of aspects 3 and 4, wherein performing step c3) is preceded by automated cutting of the high-temperature stable closed-cell rigid hard foam.

[0064] 6. The method of any of aspects 4 and 5, wherein performing step c2) is preceded by movement of the cut fiber reinforcing material by a first conveyor belt.

[0065] 7. The method of any of aspects 3 to 6, wherein steps c1) and c2) are repeated preferably 2 to 20 times, more preferably 2 to 15 times, even more preferably 2 to 10 times, and more preferably 2 to 4 times.

[0066] 8. The method of any one of aspects 3-7, wherein performing step c4) is preceded by moving the high temperature stable closed pore rigid hard foam by a first or second conveyor belt.

[0067] 9. The method of any one of aspects 3-8, wherein the compressing step is performed by vacuum infusion and / or vacuum injection.

[0068] 10. The method of any of aspects 3-8, wherein a sandwich structure composed of a fiber-reinforced, high-temperature-stable, closed-pore, rigid rigid foam is prepared in step c6), the sandwich structure comprising a first outer layer, a high-temperature-stable, closed-pore, rigid rigid foam core, and a second outer layer, and wherein step c4.1) occurs after step c4), and wherein step c4.1) comprises receiving the fiber-reinforced material according to step c1), optionally automatically cutting the fiber-reinforced material in step c1) before receiving it, and applying the fiber-reinforced material by a first manipulator into the second mold or to the high-temperature-stable, closed-pore, rigid rigid foam as the second outer layer, and wherein these steps are preferably repeated, more preferably 2 to 20 times, more preferably 2 to 15 times, even more preferably 2 to 10 times, and more preferably 2 to 4 times.

[0069] 11. The method of aspect 10, wherein the compressing step is performed by resin transfer molding.

[0070] 12. The method of any one of aspects 3 to 11, wherein the fiber reinforced material comprises a dry fabric in the form of a woven fabric, knitted fabric, fiber, tape, a scrim in the form of a non-directional ply or in the form of a unidirectional ply, and the fiber reinforced material preferably comprises natural spun or synthetic fibers, metal fibers, carbon fibers, glass fibers, polymer fibers, or aramid fibers.

[0071] 13. The method of aspect 10, wherein the compressing step is carried out by pressing, in which the first and second molds function as pressing media, or by autoclave molding, in which the first and second molds can be hermetically sealed.

[0072] 14. The method of any one of aspects 3-13, wherein the high temperature stable closed pore rigid hard foam is heated either before being applied to the lower outer layer or after being applied to the lower outer layer.

[0073] 15. The method of any one of aspects 13 and 14, wherein the fiber reinforced material is a multilayer laminate, a pre-impregnated thermosetting resin fabric and / or thermoplastic resin fabric in the form of a woven fabric, a knitted fabric, a fiber, a tape, a scrim in the form of a non-directional ply or in the form of a unidirectional ply, wherein the fiber reinforced material preferably comprises natural textile or chemical fibers, metal fibers, carbon fibers, glass fibers, polymer fibers or aramid fibers, and wherein the resin fabric preferably comprises a formaldehyde resin, preferably phenol-formaldehyde (PF) and melamine-formaldehyde (MF), and a reactive resin, preferably unsaturated polyester resin (UP) and epoxy resin (EP).

[0074] 16. The method of any of aspects 3-15, wherein the first, second, third and / or fourth manipulators are vacuum manipulators, preferably camera-controlled.

[0075] 17. The method of any one of aspects 3-16, wherein, as a further reinforcement, the fiber reinforcement material is stitched to the high-temperature stable closed-pore rigid foam before introducing the fiber reinforcement material and the high-temperature stable closed-pore rigid foam into the mold, the stitching being performed automatically after the fiber reinforcement material is applied to the high-temperature stable closed-pore rigid foam by a manipulator, and / or, as a further reinforcement, the high-temperature stable closed-pore rigid foam is stitched without weaving, and / or, as a further reinforcement, the fiber reinforcement material is stitched without the high-temperature stable closed-pore rigid foam.

[0076] 18. The method of any of aspects 1 and 2, wherein a high temperature stable closed pore rigid rigid foam is provided, received by a manipulator, and processed by automated tape placement (ATP) or automated fiber placement (AFP) to provide a sandwich structure comprised of the fiber reinforced high temperature stable closed pore rigid rigid foam.

[0077] 19. The method of any of aspects 3-17, wherein a sandwich structure comprised of fiber-reinforced closed-pore rigid high-temperature hard foam is received by the first, second, third, fourth, or fifth manipulator and fiber-reinforced by automated tape placement (ATP) or automated fiber placement (AFP).

[0078] 20. The method of embodiment 18, wherein the high temperature stable closed pore rigid hard foam is cut before being embedded.

[0079] 21. The method of any one of aspects 18-20, wherein a plurality of plies of fiber reinforcement material, preferably 2 to 19, more preferably 2 to 15, even more preferably 2 to 10, and more preferably 2 to 4 plies, being fibers or tapes, are applied to the high temperature stable closed-cell rigid hard foam or sandwich structure.

[0080] 22. The method of any one of aspects 18 to 21, wherein the processing temperature is up to 300°C, up to 250°C, up to 230°C, up to 220°C, up to 200°C, preferably up to 180°C.

[0081] 23. The method of any one of aspects 18-22, wherein the fabric, fiber, or tape is a thermoplastic or thermosetting resin, and the thermoplastic resin is preferably melted by a laser or flame.

[0082] 24. The method of any of aspects 1-23, monitored by a monitoring system that displays and controls the current method step and position of the automation unit.

[0083] 25. The method of aspect 24, wherein the surveillance system comprises a camera.

[0084] 26. The method of aspect 24 or 25, wherein the monitoring system comprises a programmable logic controller (PLC) and receives global position data from imported CAD data of the components.

[0085] 27. The method of any one of aspects 1-26, wherein the high-temperature stable closed-pore rigid hard foam comprises polymethacrylimide, polysulfone, polymethyl methacrylate (PMMA), polyurethane (PU), polyvinyl chloride (PVC), polyetherimide (PEI), polyetheretherketone (PEEK), polyethylene terephthalate (PET), and / or polyetherketone (PEK), preferably polymethacrylimide and / or polysulfone.

[0086] 28. High temperature stable closed pore rigid foam with a strength of 25-330 kg / m 3 , preferably 20 to 320 kg / m 3 , more preferably 25 to 220 kg / m 3 , and even more preferably 40 to 130 kg / m 3 , particularly preferably 45 to 115 kg / m 3 28. The method of embodiment 27, comprising polymethacrylimide having a density of

[0087] 29. The method of any one of aspects 1-28, wherein the application of the fiber reinforcement is reversible.

[0088] 30. The method of any one of aspects 3 to 29, wherein the sandwich structure has connecting elements and / or other force introduction elements, preferably seams, studs and / or empty tubes.

[0089] 31. The method according to aspect 30, wherein the connecting element and / or the force-introducing element consists of plastic and / or metal, preferably aluminum.

[0090] 32. The method of any of aspects 30 and 31, wherein prior to step c3), connecting elements and / or force-introducing elements are introduced into the high-temperature-stable, closed-pore, rigid, hard foam. The high-temperature-stable, closed-pore, rigid, hard foam including connecting elements and / or force-introducing elements is already provided.

[0091] 33. The method of any of aspects 30 and 31, wherein a connecting element and / or a force introduction element is applied in step c2.1) to the fiber-reinforced material after step c2) and / or in step c3.1) to the high-temperature-stable closed-pore rigid hard foam after step c3).

[0092] 34. The method of any of aspects 30 and 31, wherein the connecting element and / or force-introducing element is introduced into a sandwich structure composed of a fiber-reinforced, high-temperature stable, closed-pore, rigid hard foam.

[0093] 35. The method of any one of aspects 3-34, wherein the sandwich structure has an adhesive layer between the high temperature stable closed pore rigid hard foam and the outer layer.

[0094] 36. The method of any one of aspects 3-34, wherein the sandwich structure does not have an adhesive layer between the foam and the outer layer.

[0095] 37. A manufacturing line for carrying out the method according to any one of embodiments 1 to 36.

[0096] 38. The manufacturing line of embodiment 37, wherein the manufacturing line has at least one conveyor belt and at least one manipulator, and the manufacturing line preferably further has at least one mold part.

[0097] 39. The production line of aspect 36 or 37, wherein the production line has a monitoring system, the monitoring system having at least one sensor, at least one controller, and a display.

[0098] 40. The manufacturing line of embodiment 39, wherein the sensor is a camera, a light barrier, a pressure sensor, and / or a touch sensor.

[0099] 41. The production line of any of aspects 39 and 40, wherein the display is an audio and / or visual display, preferably a monitor.

[0100] 42. The manufacturing line of any one of aspects 39-41, wherein at least one sensor is connected to a controller, and the controller is capable of controlling an automated method.

[0101] 43. The manufacturing line of any one of aspects 39 to 42, wherein the display and the controller are connected to each other, and the controller can be controlled using the display.

[0102] 44. The manufacturing line of any of aspects 39-43, wherein the monitoring system includes a programmable logic controller (PLC) and receives global position data from imported CAD data of the components.

[0103] Method for automated manufacturing of lightweight components The problem underlying the present invention is solved by a method for the automated manufacturing of lightweight components, which method comprises the following steps: a) providing a high temperature stable closed pore rigid hard foam; b) providing a fiber reinforcement material; c) automatically applying a fiber reinforcement material to a high temperature stable closed pore rigid hard foam; Includes.

[0104] The high temperature stable closed cell rigid hard foam has a Tg of 100.0° C. or higher, preferably 125.0° C. or higher, more preferably 130.0° C. or higher, more preferably 150.0° C. or higher, more preferably 160.0° C. or higher, more preferably 170.0° C. or higher, more preferably 180.0° C. or higher, more preferably 190.0° C. or higher, and more preferably 200.0° C. The lightweight component is preferably an aviation and aerospace component, preferably a wing or the like.

[0105] The advantage of using high-temperature-stable, closed-pore, rigid rigid foams is that they have precise, stable geometries and sufficient compressive strength and thermal stability for automated tape placement (ATP) and automated fiber placement (AFP) lamination methods. The rigidity of high-temperature-stable, closed-pore, rigid rigid foams means they can be easily handled with modern manipulators, allowing for precise pick-and-place operations. In automated processes, high-temperature-stable, closed-pore, rigid rigid foams have the added advantage that, due to their closed pores, they can be handled with vacuum manipulators when reduced pressure is applied. Furthermore, the opposing magnets of magnetic manipulators can be easily applied because they adhere firmly to the surface due to the closed surface of non-magnetic, high-temperature-stable, closed-pore, rigid rigid foams. In contrast to honeycomb materials, closed-pore rigid foams have a continuous, consistent surface, allowing microscopic hairs to develop shear adhesion, making it possible to use adhesive manipulators.

[0106] Force-bearing elements can be easily inserted into the high-temperature stable, closed-cell, rigid rigid foam structure, and laying and fastening materials can be applied without difficulty over the entire surface area of ​​the material. Metal sheets can be applied with reduced air entrapment. Furthermore, cut-to-size applications are possible with reduced stabilization requirements or without the stabilization process altogether.

[0107] The automation of fiber plastic processing techniques using high temperature stable closed cell rigid hard foams allows for significant reductions in process time and costs compared to manual process steps.

[0108] Furthermore, due to the strength and rigidity of high-temperature stable, closed-cell rigid foam, textile reinforcement structures can be applied and draped directly onto uniform surfaces in an automated manner using automated systems / robots / actuators / effectors. Due to the high thermal stability of high-temperature stable, closed-cell rigid foam, it is also possible to lay and solidify pre-impregnated fibers, tapes, fabrics, scrims, etc. with thermosetting and / or thermoplastic matrices, or to activate the textile binder through fiber / tape placement techniques. The stitching technique, popular in preform technology, can also be used as an additional reinforcement method in manufacturing. For this purpose, a needle pierces the high-temperature stable, closed-cell rigid foam and introduces a textile reinforcement structure (e.g., suture thread). Here, it is possible to stitch the foam itself and / or the foam alone together with the textile outer layer, the fiber reinforcement material. The reinforcement structure is then impregnated and solidified in a subsequent resin infusion process.

[0109] Step c) preferably comprises the following component steps: c1) applying a fiber reinforcement material by a first manipulator; c2) laying a fiber reinforced material into the first mold as a first outer layer by a first manipulator; c3) receiving, by the first manipulator or the second manipulator, a high temperature stable closed pore rigid hard foam; c4) applying a high temperature stable closed pore rigid hard foam to the first outer layer by the first manipulator or the second manipulator; Optionally, c5) receiving the fiber reinforced material by the first or second manipulator and laying the fiber reinforced material by the first or second manipulator into the second mold part as a second outer layer or onto the high temperature stable closed pore rigid hard foam; c6) compressing the fiber reinforced material and the high temperature stable closed pore rigid foam to create a sandwich structure comprised of a fiber reinforced high temperature stable closed pore rigid foam, the sandwich structure comprising a first outer layer, a high temperature stable closed pore rigid foam, and optionally a second outer layer, the first and second outer layers forming upper and lower outer layers surrounding the high temperature stable closed pore rigid foam; It has.

[0110] In step c2), before carrying out step c6), auxiliary agents may be applied to the first outer layer and / or the high-temperature stable closed-cell rigid foam, where the auxiliary agents are fillers, dyes and / or flow agents, preferably formaldehyde resins, in particular phenol-formaldehyde (PF) and melamine-formaldehyde (MF), and reactive resins, preferably unsaturated polyester resins (UP) and epoxy resins (EP), and polycaprolactam and / or polypropylene.

[0111] The application of flow agents has the advantage that the fiber reinforcement material is tightly bound by a high temperature stable closed cell rigid hard foam.

[0112] Prior to step c1), at least one foil and / or at least one membrane may be placed on the first mold, preferably the at least one foil and / or at least one membrane is placed by the first manipulator or the second manipulator.

[0113] After step c4) and before step c6), at least one foil and / or at least one membrane may be applied to the high temperature stable closed pore rigid hard foam by the first manipulator or the second manipulator, or after step c4) and before step c6), at least one foil and / or at least one membrane may be applied to the optional second outer layer by the first manipulator or the second manipulator.

[0114] The application of at least one foil and / or at least one membrane has the advantage that the sandwich structure is stabilized and the surface of the sandwich structure is smoother and therefore has better aerodynamic properties.

[0115] The manipulators used may be vacuum, mechanical, magnetic and / or adhesive manipulators. It is preferable to use vacuum manipulators. Mechanical manipulators may be pneumatically, hydraulically or electrically operated. In particular, mechanical manipulators may be parallel, angular, radial and three-point grippers. Magnetic manipulators may be permanent magnet and / or electromagnetic manipulators.

[0116] The advantages of vacuum manipulators are that vacuum-assisted gripping protects the workpiece from damage and the construction of the manipulator is space-saving.

[0117] Preferably, step c1) is preceded by an automatic cutting of the fiber-reinforced material to size, which can be done using a roll cutter, a thread cutter and / or a guillotine, which has the advantage that the fiber-reinforced material fits precisely into the first mold.

[0118] More preferably, step c4) is preceded by automated cutting of the high-temperature stable, closed-cell, rigid foam. This can be done using a roll cutter, a thread cutter, and / or a guillotine. This has the advantage that the high-temperature stable, closed-cell, rigid foam is positioned on the fiber-reinforced material in such a way that it fits precisely into the first mold.

[0119] More preferably, prior to performing step c2), the cut or uncut fiber reinforced material is moved by a first conveyor belt. The conveyor belt more preferably moves the fiber reinforced material to an area where the first or second manipulator can receive the fiber reinforced material. The placement on the conveyor belt is performed by the first, second or third manipulator. This has the advantage that the method can be further automated and therefore can be performed more quickly and at lower cost.

[0120] More preferably, steps c1) and c2) are preferably repeated, more preferably 2 to 20 times, more preferably 2 to 15 times, even more preferably 2 to 10 times, more preferably 2 to 4 times, which has the advantage that the outer layers of the sandwich structure obtain a higher material thickness and become more robust, but at the same time do not become excessively heavy and still meet the requirements of lightweight construction.

[0121] More preferably, prior to performing step c3), the high-temperature-stable, closed-pore, rigid foam is transferred by a first or second conveyor belt to an area where it can be received by a first or second manipulator. The placement on the conveyor belt can be performed by a first, second, third, or fourth manipulator. This has the advantage that the method can be further automated and therefore performed more quickly and at lower cost.

[0122] More preferably, the compressing step is carried out by vacuum infusion and / or vacuum injection, which has the advantage that only a first mould is required and therefore the manufacturing costs of the sandwich structure are lower.

[0123] Preferably, in step c6), the sandwich structure is fabricated from a fiber-reinforced, high-temperature-stable, closed-pore, rigid rigid foam, including a first outer layer, a fiber-reinforced, high-temperature-stable, closed-pore, rigid rigid foam core, and a second outer layer. The high-temperature-stable, closed-pore, rigid rigid foam core refers to a high-temperature-stable, closed-pore, rigid rigid foam surrounded by the first and second outer layers. This surrounding may be continuous or discontinuous. Step c4.1) is performed after step c4), and includes cutting and receiving the fiber-reinforced material from step c1) and applying the fiber-reinforced material to the second mold or the high-temperature-stable, closed-pore, rigid rigid foam as the second outer layer using a first manipulator. These steps are preferably repeated, more preferably 2 to 20 times, more preferably 2 to 15 times, even more preferably 2 to 10 times, and more preferably 2 to 4 times. This has the advantage that the outer layers of the sandwich structure get a higher material thickness and are therefore more robust, but at the same time are not excessively heavy and still meet the requirements of lightweight construction.

[0124] Preferably, the fiber reinforced material cut in step c4.1) is moved by a first conveyor belt so as to be received by the first manipulator in step c1).More preferably, before the fiber reinforced material is applied to the second mould in step c4.1), a film and / or membrane is applied to the second outer layer or a film and / or membrane is introduced into the second mould.

[0125] In a preferred embodiment of the method according to the invention for producing a composite material in the form of a sandwich structure, two outer layers, one upper outer layer and one lower outer layer, are produced in an automated process, which together with the core layer form a sandwich structure, which is a high-temperature stable, closed-cell rigid foam. Preferably, the compressing step c6) is carried out by resin transfer molding. This has the advantage that the sandwich structure is produced with high build quality and its surface is smooth and aerodynamic on all sides. Furthermore, a large number of items can be produced.

[0126] The thickness of the core layer, i.e., the high-temperature stable, closed-cell rigid foam, is preferably in the range of 0.50 to 200.0 mm, particularly in the range of 5.0 to 100.0 mm, and very preferably in the range of 10.0 to 70.0 mm. The thickness of the outer layer is generally in the range of 0.10 to 100.0 mm, preferably in the range of 0.50 to 50.0 mm, and more preferably in the range of 1.00 to 10.0 mm. The composite material preferably contains more than 30.0% by volume, preferably more than 50.0% by volume, and most preferably more than 80.0% by volume, of the high-temperature stable, closed-cell rigid foam. Furthermore, the core layer and / or outer layer may be provided with force introduction elements, including notches, threads, tubes, seams, studs, hooks, and / or other inserts. This has the advantage that lightweight components or sandwich structures can be adapted to their future function and no modifications to the components are required after they are manufactured. The introduction of tubes has the advantage that cables can be laid through empty pipes or fluid channels can be created. Screws, seams, hooks and studs offer the advantage of a more stable structure and can be used as connecting elements to other components. Additional layers for bonding or decorative purposes can also be present within the foam core or on the outside of the outer layer.

[0127] The fiber reinforced material is preferably a dry fabric in the form of a woven fabric, knitted fabric, fabric, tape, scrim in the form of a non-directional ply or a unidirectional ply. More preferably, the fiber reinforced material comprises natural textile or chemical fibers, metal fibers, carbon fibers, glass fibers, polymer fibers or aramid fibers. This has the advantage that the woven structure has a good ability to absorb resins and other flow agents.

[0128] The fiber-reinforced material preferably contains auxiliary agents in the form of fillers, dyes and / or flow agents, which are preferably formaldehyde resins, in particular phenol-formaldehyde (PF) and melamine-formaldehyde (MF), and reactive resins, preferably unsaturated polyester resins (UP) and epoxy resins (EP), as well as polycaprolactam and / or polypropylene.

[0129] The compressing step c6) is preferably performed by a pressing operation, in which case the first and second molds function as pressing means. The compressing step c6) can also be performed by autoclave molding, in which case the first and second molds can be hermetically sealed. The autoclave can be closed after the high-temperature stable, closed-cell rigid foam and fiber-reinforced material have been applied, and an internal pressure of at least 8 bar and a temperature of 60 to 250°C can be applied. After the curing process, the autoclave can be cooled to an internal temperature of less than 40°C. The autoclave can then be opened, releasing the sandwich structure of fiber-reinforced, high-temperature stable, closed-cell rigid foam.

[0130] Preferably, the fiber-reinforced material comprises a multilayer laminate in the form of a woven fabric, knitted fabric, fiber, tape, scrim in the form of a non-directional or unidirectional ply, a pre-impregnated thermosetting resin fabric, or a thermoplastic resin fabric when compressed by pressing or autoclave molding. The fiber-reinforced material may comprise natural or synthetic fibers, metal fibers, carbon fibers, glass fibers, polymer fibers, or aramid fibers. The resin fabric preferably comprises a formaldehyde resin, particularly phenol-formaldehyde (PF) and melamine-formaldehyde (MF), and a reactive resin, preferably an unsaturated polyester resin (UP) or an epoxy resin (EP). The pre-impregnated resin fabric bonds the fiber composite material to a high-temperature stable, closed-cell, rigid foam during compression.

[0131] Preferably, the fiber reinforced material contains 5% to 60% by weight of filler and / or dye, more preferably 10% to 40%, 20% to 30% or 25% by weight.

[0132] The advantage of compacting by autoclave molding or pressing is that it is no longer necessary to introduce flow agents into the fiber-reinforced material during compaction, which not only reduces the complexity of the operation but also reduces the possibility of air being trapped within the fiber-reinforced material.

[0133] The molding compound of the outer layer can be cured by reversible crosslinking via a hetero Diels-Alder reaction, in that molding compounds for this purpose have diene functional groups with carbon-sulfur double bonds and dienophile double bonds.

[0134] Alternatively, the curing of the molding compound in the outer layer can be carried out by reversible crosslinking via the Diels-Alder reaction, in that the polymer formulations for this purpose have dienophile functional groups which are maleimide groups, and diene functional groups which are furfural, cyclopentadienyl and 1,3-pentadienyl groups.

[0135] Preferably, the high-temperature-stable, closed-cell, rigid foam is heated before and / or after application to the lower outer layer. More preferably, the high-temperature-stable, closed-cell, rigid foam is heated by infrared radiation, near-infrared radiation, or thermally to a temperature above 100°C before pressing or closing the mold, and the high-temperature-stable, closed-cell, rigid foam is preferably formed directly by pressure during closing the pressing or autoclave mold. This has the advantage of not only improving molding but also better bonding of the fiber reinforcement material to the high-temperature-stable, closed-cell, rigid foam.

[0136] Preferably, the first and / or second, and more preferably the first, second, third and / or fourth manipulators are vacuum manipulators, preferably camera-controlled. This has the advantage that the surface of the manipulated material is gripped in a highly material-preserving manner. Furthermore, camera control allows for accurate pick-up and placement of the manipulated material, which may be a fiber-reinforced material and / or a high-temperature stable closed-cell rigid foam.

[0137] Preferably, the fiber reinforcement material is stitched to the high-temperature stable, closed-pore rigid foam as a further reinforcement of the sandwich structure before the fiber reinforcement material and the high-temperature stable, closed-pore rigid foam are introduced into the mold. The stitching is performed automatically after the fiber reinforcement material is applied to the high-temperature stable, closed-pore rigid foam by a manipulator. Alternatively or additionally, the stitching is performed as a further reinforcement to the high-temperature stable, closed-pore rigid foam that does not include the fiber reinforcement material.

[0138] In a particularly preferred embodiment, a high temperature stable closed pore rigid hard foam is provided, received by a manipulator, and processed by ATP or AFP to provide a sandwich structure comprised of fiber reinforced high temperature stable closed pore rigid hard foam.

[0139] In AFP, a laying head is preferably attached to a conventional six-axis robot to simultaneously lay several tows of continuous fiber reinforcement material onto a mold. The degrees of freedom of a robot-based AFP system allow for the laying of complex 3D components into a mesh.

[0140] AFP offers the advantage of increasing speed and precision in the production of highly engineered fiber-reinforced materials. Furthermore, AFP offers the advantage of being able to be used to manufacture complex structures that cannot be produced by other automated methods. Furthermore, it offers repeatability and low material loss.

[0141] Preferably, a sandwich structure composed of a fiber-reinforced, high-temperature stable, closed-cell rigid foam manufactured by one of the methods described herein is received by a first, second, third, fourth, or fifth manipulator and fiber-reinforced with ATP and / or AFP. This provides the advantage of further strengthening the sandwich structure. Fiber-reinforcement of the sandwich structure with AFP and / or ATP is even more advantageous because it means that complex geometries can be applied to the sandwich structure.

[0142] The accuracy of the automatic placement is ±0.10 mm, thus exceeding the accuracy requirements of the aeronautical sector by more than two times.

[0143] Preferably, AFP and ATP are planned and controlled using simulation software. Planning can be done offline. Alternatively, the AFP and / or ATP processes are performed by computer numerical control (CNC). Simulation software for composite construction allows AFP manufacturing requirements to be considered even early in the product development cycle, and therefore directly applicable to the final manufacturing process.

[0144] Preferably, the high-temperature stable closed-cell rigid foam is cut before reinforcement with AFP and / or ATP fiber reinforcement. This can be done using a roll cutter, thread cutter, and / or guillotine. This has the advantage that the sandwich structure can be cut to size for precise fit according to the component requirements before reinforcement.

[0145] Preferably, ATP or AFP applies multiple plies of fiber reinforced material, more preferably 2 to 20, even more preferably 2 to 15, even more preferably 2 to 10, more preferably 2 to 4 plies, to a high temperature stable closed cell rigid hard foam or sandwich structure.

[0146] More preferably, the processing temperature in ATP or AFP is up to 300°C, up to 250°C, up to 230°C, up to 220°C, up to 200°C, preferably up to 180°C.

[0147] More preferably, the fiber reinforced material applied by the AFP and / or ATP process comprises a fabric, fiber or tape pre-impregnated with a thermoplastic or thermosetting resin and / or a thermosetting or thermoplastic resin, the thermoplastic resin preferably being melted by a laser or a flame.

[0148] In the pre-impregnated fabrics, fibers or tapes according to the invention, the resin may be applied to the fabric in the form of a powder, melt, solution or aqueous dispersion. The thermosetting resin may be provided as a sheet molding compound (SMC) or bulk molding compound (BMC). It is preferred to use polyester or vinyl ester resins.

[0149] Further preferably, the method is monitored by a monitoring system which displays and controls the current method step and position of automated units, which are all units that operate automatically, in particular conveyor belts, manipulators, AFP and ATP machines, autoclaves, presses, RTM devices, vacuum injection and vacuum infusion devices.

[0150] The monitoring system preferably comprises a camera. More preferably, the monitoring system comprises a programmable logic controller (PLC) and receives global position data from imported CAD data of the components. More preferably, the new assembly situation can be adjusted by rapid preliminary measurements with a laser tracker. This has the advantage of a reliable process and high placement accuracy. Apart from pressing a start button, the method proceeds automatically. To facilitate input, the user interface can be made user-friendly with self-describing images.

[0151] Preferably, the high temperature stable closed pore rigid hard foam comprises polymethacrylimide, polysulfone, polymethyl methacrylate (PMMA), polyurethane (PU), polyvinyl chloride (PVC), polyetherimide (PEI), polyetheretherketone (PEEK) and / or polyetherketone (PEK), preferably polymethacrylimide and / or polysulfone.

[0152] High-temperature stable, closed-cell, rigid foams, such as polymethacrylimide (PMI) or polysulfone foams, have high stiffness in addition to low weight. This inherent stiffness is important for grip and mechanical processing. The material stays in place better during installation.

[0153] Polymethacrylimide is a type of polyimide. A copolymer of methacrylic acid and acrylonitrile is converted to polymethacrylimide by foaming at 170-250°C. Rigid PMI plastics and rigid PMI foams have high thermal stability with a glass transition temperature (Tg) of at least 180°C, are creep-resistant, stable to sustained vibration, and are notable for their high rigidity, uniform closed-cell foam structure, and easy moldability.

[0154] In rigid PMI foams, the pore structure of the polymer can be modified by specific manufacturing methods to obtain different strength values ​​in and perpendicular to the longitudinal plane.

[0155] PMI foams are typically produced in a two-step process: a) the preparation of a cast polymer and b) the expansion of the cast polymer. Foaming can also be carried out in two or more separate steps. For example, a preformed foam core can be covered with an outer layer and then the foaming process can continue. The production of such PMI foams is generally known to those skilled in the art and is described, for example, in EP 1444293, EP 1678244, and WO 2011 / 138060. PMI foams include, among others, ROHACELL® products manufactured by Evonik Industries AG. Acrylimide foams should be considered analogous to PMI foams in terms of production and processing. However, for toxicological reasons, they are less preferred compared to other foams. The required foam core can be produced by appropriate selection of glass plates in bulk polymerization or by in-mold foaming. Alternatively, the product can be produced from a foam sheet by cutting, sawing, or milling. Preferably, it is possible to cut several foam sections from a single sheet. The density of the rigid foam can be selected relatively freely. For example, it can be set to 25.0 to 330.0 kg / m 3It is possible to use PMI foams within the density range of 1000 to 15000. The advantage of sawn, cut, or machined foam core pieces over those produced by in-mold molding is that they have open pores on their surface. When they come into contact with resin-saturated fibers, some of the unhardened resin penetrates into the open pores on the foam core surface. This has the advantage that, upon hardening, a particularly strong bond is achieved at the interface between the foam core and the exterior material. As an alternative to the described PMI foam core, different rigid foam cores can also be used according to the present invention. This type of foam is common knowledge to those skilled in the art. Examples of such alternative rigid foams are, in particular, polymethyl methacrylate (PMMA) or highly crosslinked polyurethane (PU) foams.

[0156] Polysulfones, such as polysulfone (PSU), polyethersulfone (PES), and polyphenylenesulfone (PPSU), can be used within the temperature range of -100.0°C to +200.0°C. They are composed of para-linked aromatic, sulfonic, and ether groups, and in some cases alkyl groups.

[0157] Polysulfones have excellent thermal and oxidative stability, hydrolytic stability in aqueous and alkaline media, and good electrical properties. They have one of the highest operating temperatures of all thermoplastics that can be processed from the melt. Their high-temperature stability allows them to be used as flame retardants without compromising mechanical properties.

[0158] Polysulfone can be reinforced with glass fibers. The resulting composite has twice the tensile strength and three times the modulus.

[0159] Due to their closed-pore structure and high inherent rigidity, the drawbacks described for honeycomb materials do not apply to high-temperature-resistant, closed-pore, rigid foams such as polymethacrylimide (PMI) or polysulfone foams. They can be picked up, manipulated, and laid down in an automated manner by any type of manipulator, particularly vacuum, mechanical, magnetic, or adhesive manipulators. They can be easily picked up by the manipulator and precisely positioned due to the foam's rigidity. The material does not bend when gripped and can be precisely positioned with the manipulator without damaging or displacing the base on which the structure is placed.

[0160] Preferably, the high temperature stable closed cell rigid foam has a compressive strength of 20 to 330 kg / m 3 , preferably 25 to 320 kg / m 3 , more preferably 40 to 220 kg / m 3 , particularly preferably 45 to 130 kg / m 3 The polymethacrylimide has a density of

[0161] This has the advantage that the high temperature stable closed pore rigid hard polymethacrylimide foam has good mechanical properties, pressure stability under compression, and exceptional strength.

[0162] The application of the fiber reinforcement is preferably reversible, which has the advantage that the sandwich structure is recyclable and can be modified for other uses.

[0163] The lightweight components preferably have connecting elements and / or other force introduction elements, preferably seams, studs and / or empty tubes. In particular, sandwich structures preferably have connecting elements and / or other force introduction elements, preferably seams, studs and / or empty tubes. Cables can be pulled through the empty tubes. Preferably, the connecting elements and / or force introduction elements comprise or consist of plastic and / or metal, preferably aluminum.

[0164] More preferably, the connecting elements and / or force-introducing elements are introduced into the high-temperature-stable, closed-cell, rigid, hard foam before step c3), whereby a high-temperature-stable, closed-cell, rigid, hard foam comprising the connecting elements and / or force-introducing elements is already provided.

[0165] Additionally or alternatively, connecting elements and / or force introduction elements are applied in step c2.1) to the fiber reinforced material after step c2) and / or in step c3.1) to the high temperature stable closed pore rigid hard foam after step c3).

[0166] Furthermore, the connecting elements and / or force-introducing elements are additionally or alternatively introduced into a sandwich structure made of a fiber-reinforced, high-temperature stable, closed-cell rigid hard foam.

[0167] Preferably, the sandwich structure has a tie layer between the foam and the outer layer, or the sandwich structure does not have a tie layer between the foam and the outer layer.

[0168] Preferably, the fiber-reinforced material applied as the second outer layer to the high-temperature stable, closed-cell rigid foam or the second mold is automatically cut by a manipulator before being picked up and applied. This can be done using a roll cutter, a thread cutter, and / or a guillotine. This has the advantage that the fiber-reinforced material is positioned on the high-temperature stable, closed-cell rigid foam or in the second mold so that it fits precisely.

[0169] Furthermore, the problem underlying the present invention is solved by a production line for carrying out the above-mentioned method.

[0170] Preferably, the production line comprises at least one conveyor belt and / or at least one manipulator, and the production line preferably further comprises at least one mould part or AFP and / or ATP device.

[0171] More preferably, the production line includes a monitoring system, which includes at least one sensor, at least one controller, and a display. This has the advantage that the production line can automatically control and monitor the production process. The production line can be monitored by a human or a robot via the display. In particular, the monitoring system is preferably configured to display and control the current method step and position of an automated unit in the method of the present invention.

[0172] The sensor is preferably a camera, a light barrier, a pressure sensor and / or a touch sensor.

[0173] More preferably, the display is an audio and / or visual display, preferably a monitor.

[0174] More preferably, the at least one sensor is connected to a controller, which is capable of controlling the automated method.

[0175] More preferably, the display and the controller are connected to each other so that the display can be used to control the controller.

[0176] Preferably, the monitoring system comprises a programmable logic controller (PLC) and receives global position data from imported CAD data of the components.

[0177] Example Example 1 - Process times for manual and automated manufacturing In Example 1, the method for the automated production of lightweight components according to the invention was compared with a method for the manual production of lightweight components in terms of process time. For this purpose, the times of the individual method steps of the method for the automated production of lightweight components were compared with the times of the individual method steps of the manual production of lightweight components. The method steps compared were: cutting pre-impregnated fibers (cutting prepreg), producing a high-temperature stable closed-cell rigid rigid foam (core preparation), preform patch, laying of a fiber composite material as a first outer layer (outer lay-up skin), laying of a high-temperature stable closed-cell rigid rigid foam (core integration), and laying of a fiber composite material as a second outer layer (inner lay-up skin).

[0178] The results of the comparison are shown in Figure 1. The automated method saves a total of 37% of process time for the compared method steps. The automated method of cutting pre-impregnated fibers saves approximately 64% of process time compared to the manual method of cutting pre-impregnated fibers. The time required to produce high-temperature stable closed-cell rigid rigid foam is approximately the same for the automated method of lightweight component manufacturing and the manual method of lightweight component manufacturing. The automated method of lightweight component manufacturing saves 66% of process time for the method step of preform patching, 67% for the method step of laying high-temperature stable closed-cell rigid rigid foam, and 76% for laying fiber composite material as the second outer layer compared to the manual method of lightweight component manufacturing.

Claims

1. 1. A method for automated manufacturing of lightweight components, comprising the steps of: a) providing a high temperature stable closed pore rigid hard foam; b) providing a fiber reinforcement material; c) automatically applying the fiber reinforcement material to the high temperature stable, closed pore, rigid, hard foam; Including, the high temperature stable closed cell rigid hard foam has a Tg of 100°C or greater; A method wherein said method is monitored by a monitoring system which displays and controls the current method step and position of an automation unit.

2. 10. The method of claim 1, wherein the high temperature stable closed cell rigid hard foam has a Tg of 130°C or higher, preferably 180°C or higher.

3. The method of claim 1 or 2, wherein the lightweight components are aviation and aerospace components.

4. Step c) comprises the following component steps: c1) applying said fiber reinforcement material by a first manipulator; c2) laying the fiber reinforcement material into a first mold part as a first outer layer by the first manipulator; c3) receiving the high temperature stable closed pore rigid hard foam by the first manipulator or the second manipulator; c4) applying the high temperature stable closed pore rigid hard foam to the first outer layer by the first manipulator or the second manipulator; Optionally, c5) receiving the fiber reinforced material by the first or second manipulator and laying the fiber reinforced material by the first or second manipulator into a second mold part as a second outer layer or onto the high temperature stable closed pore rigid hard foam; c6) compressing the fiber reinforced material and the high temperature stable closed pore rigid foam to create a sandwich structure comprising a first outer layer, a high temperature stable closed pore rigid foam, and optionally a second outer layer, the first and second outer layers forming upper and lower outer layers surrounding the high temperature stable closed pore rigid foam; The method according to any one of claims 1 to 3, comprising:

5. The method of claim 4 , wherein the compressing step is performed by vacuum infusion and / or vacuum injection.

6. In step c6), a sandwich structure including the first outer layer, the high-temperature stable closed-cell rigid hard foam core, and the second outer layer is prepared by compression; 5. The method according to claim 4, wherein step c4.1) is performed after step c4), and comprises receiving the fiber reinforced material according to step c1), optionally automatically cutting said fiber reinforced material before step c1), and applying said fiber reinforced material by said first manipulator as a second outer layer into a second mould part or to said high-temperature stable closed-cell rigid hard foam, and wherein these steps are preferably repeated, more preferably repeated 2 to 20 times, more preferably repeated 2 to 15 times, even more preferably repeated 2 to 10 times, more preferably 2 to 4 times.

7. The method of claim 6, wherein said compressing step c6) is performed by resin transfer molding.

8. 7. The method of claim 6, wherein the compressing step c6) is performed by pressing, in which the first and second mold parts function as pressing media, or by autoclave molding, in which the first and second mold parts can be hermetically sealed.

9. The method according to any one of claims 4 to 8, wherein the first and / or second manipulator is a vacuum manipulator, preferably camera controlled.

10. 10. The method of claim 1, wherein the high temperature stable, closed pore, rigid, hard foam is provided, received by a manipulator, and processed by automated tape placement (ATP) or automated fiber placement (AFP) to provide a sandwich structure comprised of fiber reinforced, high temperature stable, closed pore, rigid, hard foam.

11. 10. The method according to any one of claims 4 to 9, wherein the sandwich structure made of a fiber reinforced high temperature stable closed pore rigid hard foam is received by a first, second or third manipulator and fiber reinforced by automated tape placement (ATP) or automated fiber placement (AFP).

12. The method of any one of claims 1 to 11, wherein the surveillance system comprises a camera.

13. The method of any one of claims 1 to 12, wherein the monitoring system comprises a programmable logic controller (PLC) and receives global position data from imported CAD data of the components.

14. 14. The method according to any one of claims 1 to 13, wherein the high temperature stable closed cell rigid hard foam comprises polymethacrylimide, polysulfone, polymethyl methacrylate, polyurethane, polyvinyl chloride, polyethylene terephthalate, polyetherimide, polyetheretherketone and / or polyetherketone, preferably polymethacrylimide and / or polysulfone.

15. The high-temperature stable closed-cell rigid hard foam has a strength of 20 to 330 kg / m ３ , preferably 25 to 320 kg / m ３ , more preferably 40 to 220 kg / m ３ , particularly preferably 45 to 130 kg / m ３ 15. The method of claim 14, comprising polymethacrylimide having a density of

16. The method according to any one of claims 4 to 15, wherein the sandwich structure has connecting elements such as seams, studs or other force introduction elements.

17. 17. A production line for carrying out the method according to any one of claims 1 to 16, said production line having a monitoring system, said monitoring system having at least one sensor, at least one controller and a display, said monitoring system being configured to display and control a current method step and position of said automation unit in the method according to any one of claims 1 to 16.

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