METHOD FOR PRODUCING A PARTIALLY ADDITIVELY MANUFACTURED COMPONENT FOR A TECHNICAL DEVICE

Description

[0001] The invention relates to a method for producing a partially additively manufactured

[0002] Component for a technical device according to claim 1. Preferred embodiments of the invention are defined in the dependent claims. State of the art

[0003] Technical devices such as machines, apparatus or systems, or their individual components, are often exposed to high loads during operation. For example, high loads can occur in components of a process engineering device through which fluid flows due to the fluids being conducted through the component. For example, process media are supplied and removed through the headers of a heat exchanger, e.g. a brazed plate-fin heat exchanger, to carry out a heat exchange. Such components and their walls must therefore often withstand high pressures, stresses and other loads. For example, the walls of pressure vessels can also be exposed to such high loads, e.g. in containers for storing substances under positive or negative external or internal pressure.

[0004] To dimension such components, one can, for example, start with a position of the component's highest load. The wall thickness of the component at this position is selected so that the wall can withstand the high loads there. Often, this position with the highest loads defines the wall thickness of the entire component.

[0005] DE 10 2018 213 416 A1, for example, relates to the production of a component using a generative or additive manufacturing process. Specifically, DE 10 2018 213 416 A1 describes a method for planning tool paths along which a tool is to be moved relative to the component during the generative manufacturing process in order to deposit reinforcing fibers along fiber paths to reinforce the component to be manufactured using the generative manufacturing process. For this purpose, component data characterizing a virtual model of the component to be manufactured is received. An input is received which characterizes at least one load acting on the virtual model at at least one location and the location.A topology optimization is carried out based on the input and the component data, whereby the topology optimization determines the fiber paths and the resulting tool paths in such a way that a load on the virtual model resulting from the load fulfills a predetermined optimization criterion.

[0006] According to DE 10 2018 213 416 A1, the entire component is manufactured entirely using the generative or additive manufacturing process, which, however, involves a high expenditure of time and money.

[0007] It is desirable to improve the production of components for technical devices. Disclosure of the invention

[0008] Against this background, the present invention proposes a method for producing a partially additively manufactured component for a technical device. Embodiments are the subject of the dependent patent claims and the following description.

[0009] The invention is based on the discovery of producing a simple basic structure of a component with a minimum required wall thickness using a non-additive manufacturing process and of specifically reinforcing or stiffening this basic structure at specific positions exposed to increased mechanical stresses by applying material using additive manufacturing. These areas or positions of the basic structure to be reinforced are determined by an optimization method or an optimization algorithm.

[0010] Within the scope of the present method, a basic structure of the component with a predetermined wall thickness is manufactured using a non-additive manufacturing process. At least one region of the component, expediently at least one region to be reinforced, is determined, identified, or localized using an optimization process. In this at least one region, a support structure is applied to the basic structure using an additive manufacturing process.

[0011] The basic structure expediently represents a basic volume or a first material volume. The support structure represents in particular an additional volume or a second material volume. The entire component or a total volume of the component is thus formed by the basic structure or the basic volume and the support structure or the additional volume applied thereto.

[0012] The basic structure with the specified wall thickness can be manufactured, for example, using a non-additive manufacturing process such as conventional primary forming, e.g., casting, or conventional forming, e.g., bending. For example, an entire wall defining the component can be manufactured as a single piece. Likewise, individual partial walls can be manufactured separately, e.g., using non-additive manufacturing processes such as conventional primary forming or conventional forming, and combined to form the overall wall of the component, e.g., using a joining process, such as welding.

[0013] In the present context, a non-additive manufacturing process is understood to mean, for example, a manufacturing process in accordance with the DIN 8580 standard, which is not counted as additive manufacturing. Other examples of non-additive manufacturing processes include conventional primary forming processes such as casting, e.g. gravity casting, die casting, low-pressure casting, centrifugal casting, continuous casting, injection molding, etc., or pressing, e.g. transfer molding, extrusion, etc. Further examples of non-additive manufacturing processes include conventional forming processes such as bending, rolling, open-die forging, drop forging, impact extrusion, extrusion, deep drawing, etc. Furthermore, for the non-additive production of the basic structure, conventional joining processes, e.g. welding, soldering, gluing, etc., or conventional cutting processes, e.g. machining, shear cutting, flame cutting, spark erosion, etc., can be used.

[0014] In particular, the wall thickness of the base structure can be specified as the smallest possible, particularly the minimum, wall thickness, which is expediently designed for a low load acting on the component or which the base structure requires at least to be able to withstand the acting loads. The base structure is then specifically reinforced by the support structure at points with higher loads, so that the component can also withstand the higher loads acting at these points. The support structure can thus be specifically applied to particularly stressed positions on the component, and the component can be individually adapted to the specific load case.

[0015] The base structure and the support structure can, in principle, be made of the same material or, if appropriate, of different materials. For example, in the case of different materials, specific material properties can be exploited in specific areas.

[0016] The additive manufacturing process makes it possible to apply the support structure with pinpoint accuracy, thus creating precise local reinforcements of the base structure. Additive manufacturing is a manufacturing process in which a three-dimensional object or structure is created by consecutively adding a material layer by layer. A new layer of material is applied one after the other, solidified, and firmly bonded to the underlying layers, e.g., using a laser, electron beam, or arc.

[0017] The areas or locations where the basic structure is to be reinforced by the support structure are determined, identified, or localized within the scope of this method using the optimization method or a corresponding optimization algorithm. Optimization methods or optimizations generally refer to analytical or numerical calculation methods for finding optimized, particularly minimized or maximized, parameters of a complex system.

[0018] For this purpose, an optimization problem can be formulated, where a solution space Ω, i.e. a set of possible solutions or variables x , as well as an objective function f To solve this optimization problem, a set of values ​​of the variables or solutions x ∈ Ω such that f ( x) satisfies a given criterion, for example, maximum or minimum. Furthermore, boundary or secondary conditions can also be specified, whereby feasible solutions x must satisfy these specified boundary conditions. In the present case, for example, an objective function can be defined to solve the optimization problem in such a way that the overall wall thickness of the component is minimized as much as possible.

[0019] The optimization procedure is particularly useful when performed based on a numerical solution, in particular a finite element analysis (FE analysis). The component is divided into a finite number of subregions, known as finite elements. Each finite element belonging to an optimization space is assigned a pseudodensity. The stiffness of the structure is primarily influenced by this pseudodensity, with elements whose pseudodensity lies below a specified limit being iteratively removed.

[0020] Thus, the component can be divided into a multitude of individual areas within the optimization process, and for each of these areas, it can be individually determined whether material should be applied to each of these areas using additive manufacturing. For example, a minimized total wall thickness can be determined in each of these individual areas by solving the optimization problem. Based on the result of the optimization process, the corresponding support structure is applied individually in the correspondingly determined areas. The total wall thickness of the component, i.e., the sum of the specified wall thickness of the base structure and the support structure, is therefore not constant and can vary across the entire component.

[0021] Conventionally, a constant wall thickness is often specified for a component, which is based on the wall thickness at the position with the highest load. Often, the component can have a thicker wall thickness than actually required at points with lower loads, which results in high material consumption and thus unnecessary costs.

[0022] Instead of a component with a constant wall thickness, the present method can be used to particularly expediently produce a component with an individual, specially adapted wall thickness profile or wall thickness progression, in particular with an individual volume distribution or an individual progression of different materials. Producing such a non-constant wall thickness profile or an uneven distribution of different materials using conventional, non-additive manufacturing processes such as conventional primary forming or conventional forming can often prove very complex.

[0023] The present process now provides a way to produce a partially additively manufactured component, with the base structure being manufactured non-additively and the support structure being manufactured additively. The base structure can be manufactured cost-effectively and with minimal material consumption using the respective non-additive manufacturing process. The use of the additive manufacturing process can be reduced, thus also saving costs and materials. The component can be manufactured cost-effectively, with minimal material consumption, and with reduced weight, and can be optimally adapted to the subsequent application and its field of use.

[0024] The present invention thus proposes an improved manufacturing method of components for technical devices, which involves low material, time and cost expenditure.

[0025] In contrast to the present method, according to DE 10 2018 213 416 A1, explained above, a component can only be manufactured entirely using a generative or additive manufacturing process. Although DE 10 2018 213 416 A1 allows reinforcement of a component using reinforcing fibers, not only these reinforcing fibers but the entire component is additively manufactured, which is associated with high costs and time expenditure. Therefore, within the scope of DE 10 2018 213 416 A1, it is not possible to manufacture a component only partially additively. The topology optimization described therein cannot be used to determine areas on a non-additively manufactured base structure in which additional material is applied to the base structure as a support structure using additive manufacturing.According to DE 10 2018 213 416 A1, all areas in which material is applied using additive manufacturing to produce the component are determined. In contrast, the present invention enables improved, more cost-effective, and less complex component production.

[0026] Advantageously, the specified wall thickness of the basic structure is dependent on a minimum required wall thickness or is specified as this minimum required wall thickness in order to be able to withstand a maximum design pressure. Design pressure, design pressure, or calculation pressure is understood to mean, in particular, a pressure that acts on the wall of the component from the inside or outside during regular operation of the component. The wall thickness of the basic structure is expediently designed in such a way that it can withstand the design pressure expected during later operation of the component. It is particularly expedient to determine the minimum required wall thickness in accordance with the standards DIN EN 13445-3 Chapter 7 or ASME VIII-1 Subsec. A UG-27, UG-28, which define the design of the wall thickness as a function of a permissible design or calculation pressure.For example, the minimum required wall thickness can be determined according to the boiler formula as defined in the standards DIN EN 13445-3 Chapter 7 and ASME VIII-1 Subsec. A UG-27, UG-28.

[0027] Alternatively or additionally, the specified wall thickness of the basic structure is particularly expediently specified depending on the minimum required wall thickness or as the minimum required wall thickness in order to be able to withstand loads in areas far away from faults. Faults are to be understood in particular as global faults or external sources of disturbance which, during operation of the component, can exert loads on the component in addition to the design or internal pressure. Such global faults can be of various natures and include, for example, specific mechanical faults in the component itself, such as openings, bends, connections to other components, etc., or also external temperature or pressure fluctuations as well as external weather or climatic conditions such as earthquakes, gusts of wind, etc.Areas far away from global faults are defined in particular in the standard DIN EN 13445-3 Annex C, in particular as areas in which stress, pressure and mechanical loads are each below specified limit values.

[0028] The minimum required wall thickness and thus the wall thickness of the base structure are thus expediently specified in such a way that the expected design pressure during subsequent regular operation can be withstood without the additional support structure in areas far away from defects. The support structure is expediently applied to the base structure using additive manufacturing in areas of the component that are subject to stress from sources of interference or defects. These can be, for example, mechanical stresses due to openings, bends, connections, etc.

[0029] In particular, the specified wall thickness of the basic structure corresponds to this minimum or minimum required wall thickness. The basic structure can thus be manufactured with the lowest possible material consumption. Furthermore, the wall thickness can expediently also be somewhat thicker than the minimum required wall thickness and thus lie in particular between the minimum or minimum required wall thickness and a maximum or maximum required wall thickness. For example, the specified wall thickness can exceed the minimum or minimum required wall thickness by a maximum of 50%, in particular by a maximum of 25%, furthermore in particular by a maximum of 15%, furthermore in particular by a maximum of 10%, furthermore in particular by a maximum of 5%. The basic structure can thus be manufactured with the smallest possible or even the smallest possible wall thickness in a conventional, non-additive manner.At specific points of increased stress, the support structure can be applied using additive manufacturing so that the component can safely withstand all loads during later operation.

[0030] Advantageously, an optimized wall thickness is determined for at least one area during the optimization process. A maximum overall wall thickness is expediently specified for the component, which is, for example, sufficiently large so that the component can withstand the highest load. For the individual areas of the component, it is expediently assessed whether the overall wall thickness can be reduced, and the value with which the component can withstand the loads acting on the respective area is determined as the optimized wall thickness. In areas with high or highest loads, the maximum overall wall thickness is hardly reduced or not reduced at all. If necessary or in the case of very high loads, the maximum overall wall thickness can be increased even further. In areas with low loads, the overall wall thickness can be reduced to the maximum or minimized.Alternatively, a minimum total wall thickness can be assumed, and during the optimization process, it can be useful to determine where the total wall thickness should be increased based on the loads acting there. This minimum total wall thickness can, for example, correspond to the specified wall thickness of the base structure.

[0031] In particular, the optimized wall thickness for each individual area represents the smallest possible wall thickness at which the specified structural properties of the component can still be achieved.

[0032] Advantageously, depending on the optimized wall thickness in at least one specific region, the support structure is applied to the non-additively manufactured base structure by means of the additive manufacturing process. In particular, a wall thickness of the support structure in the individual regions is determined depending on a difference between the optimized wall thickness and the specified wall thickness. A thickness, height, or strength of a layer applied to the non-additively manufactured base structure by the additive manufacturing process is expediently specified by this difference.

[0033] Preferably, during the optimization process, an adjustment of a locally required wall thickness of the component, in particular a minimization of the wall thickness or the total wall thickness of the component, is carried out as a function of loads or stresses acting on the component during operation. The stresses acting on the component can be formulated accordingly in the optimization problem. Particularly expediently, the correspondingly minimized total wall thickness can be determined as the optimized wall thickness. Expediently, the corresponding support structure is applied to the base structure in the respective areas so that the sum of the specified wall thicknesses of the base structure and the support structure corresponds to the optimized or minimized total wall thickness determined for the respective area.

[0034] Preferably, a total wall thickness in the at least one region, composed of the predetermined wall thickness of the base structure and a thickness of the support structure, is determined during the optimization process in such a way as to be able to withstand a load acting on the component in the at least one region during operation. Thus, the thickness of the support structure and also the total wall thickness can be determined particularly expediently depending on the predetermined wall thickness of the base structure and also depending on the loads acting on the component during subsequent operation. This expediently enables the best possible combination of non-additive and additive manufacturing.

[0035] Preferably, the stiffness of the component and / or a maximum stress occurring in the component and / or a geometric boundary condition are taken into account as a boundary condition during the optimization process. Preferably, the maximum stress occurring is limited during the optimization process. Expediently, the stiffness, the moment of inertia or various geometric aspects can also be taken into account as boundary conditions. For example, the boundary condition specified for the optimization process is that a specified stiffness of the component must not be undercut. In particular, the overall wall thickness is minimized or the optimized wall thickness is determined during the optimization process so that the specified boundary condition is not violated and so that the component has at least the specified stiffness or does not exceed a maximum stress.

[0036] According to a preferred embodiment, topology optimization is carried out during the optimization process. Topology optimization is understood to mean, in particular, computer-based calculation methods for determining the most favorable structure or topology of a component. For example, a geometric body can be specified as a maximum installation space that the component should occupy. The maximum installation space can be divided into individual elements or areas, and as a result of the topology optimization, it is expediently determined which individual elements or areas of the installation space should be occupied with material. For example, it can be determined which elements are required to conform to the set boundary conditions. The other elements are iteratively eliminated. For example, in the course of so-called material topology optimization, the geometry of the component can be described in a design space.Each element in the design space can be assigned a density or pseudo-density. The individual densities can, for example, each take on values ​​between 0 and 100%, and the individual elements can be retained or eliminated based on a threshold value.

[0037] It is understood that the optimization method should not be limited to a topology optimization with pseudodensities, but that other optimization methods with other approaches can also be used.

[0038] Alternatively or additionally, a material optimization of the component is preferably performed during the optimization process. To solve the optimization problem, the objective function can, for example, be defined such that the material required for the wall of the component is minimized.

[0039] Alternatively or additionally, load optimization and / or stress optimization are preferably performed during the optimization process. This allows, for example, the component to be optimally adapted to the loads or stresses occurring. Alternatively or additionally, geometry optimization is preferably performed during the optimization process. For example, the geometry or shape of the component can be adapted depending on specified boundary conditions.

[0040] Alternatively or additionally, flow optimization can preferably be performed during the optimization process. In particular, the component can be specifically adapted to the fluidic requirements, for example, to enable uniform flow without varying or significantly different flow velocities, or to prevent areas of slow or no flow, i.e., so-called dead spaces, from occurring, which could lead to fluid separation.

[0041] Advantageously, the optimization method is carried out as a function of a simulation of the component, in particular a numerical simulation, and further in particular a simulation of the technical device comprising the component. In particular, a static or dynamic simulation can be carried out, for example a thermo-mechanical strength simulation. With the help of the simulation, the component or the entire technical device including the component can be theoretically reproduced. The behavior of the component during regular operation as well as the stresses, loads, etc. acting on the component can be simulated. In particular, the total wall thickness of the component can be changed during the simulation in order to investigate the behavior of the component with different wall thicknesses.

[0042] According to a particularly advantageous embodiment, the simulation of the component, in particular the technical device, is carried out using a finite element method (FEM). The finite element method is a numerical procedure based on the numerical solution of a complex system of partial differential equations. The component or device is divided into a finite number of simple sub-regions, i.e., finite elements, whose physical or thermo-hydraulic behavior can be calculated based on their simple geometry. In each of the finite elements, the partial differential equations are replaced by simple differential equations or by algebraic equations. The resulting system of equations is solved to obtain an approximate solution to the partial differential equations.The physical behavior of the entire body is simulated during the transition from one element to the adjacent element using predetermined continuity conditions. This type of finite element simulation is particularly advantageous for implementing an optimization process. For example, within the framework of this method, individual finite elements can be examined to determine whether they should be filled with a corresponding material as part of the base or support structure.

[0043] According to a particularly preferred embodiment, the support structure or the additional volume is applied to the base structure by means of so-called wire and arc additive manufacturing (WAAM). During this WAAM process, individual layers are created using a consumable wire and an arc. For this purpose, welding torches, for example for gas metal arc welding, can be used, with an arc burning between the welding torch and the component to be manufactured. A suitable material, e.g. in the form of a wire or strip, is continuously fed in and melted by the arc. This process forms molten droplets that transfer to the workpiece to be manufactured and firmly bond to it.The respective material can, for example, be supplied as a consumable wire electrode of the welding torch, with the arc burning between this wire electrode and the component. It is also conceivable to supply the respective material in the form of an additional wire, which is melted by the arc of the welding torch.

[0044] Alternatively or additionally, other additive manufacturing processes can be used, during which the respective material of the support structure or additional volume is applied, for example, in powder form or in the form of wires or strips, and exposed to a laser and / or electron beam. In this way, the respective material can be subjected to a sintering or melting process to solidify it. After creating one layer, the next layer can be created in a similar manner. Such additive manufacturing processes include selective laser sintering (SLS), selective laser melting (SLM), electron beam melting (EBM), stereolithography (SL), or fused deposition modeling (FDM) or fused filament fabrication (FFF).

[0045] Alternatively or additionally, additive manufacturing processes can be used that do not use a laser beam, electron beam, or arc. The support structure can preferably be applied to the base structure using cold spraying or cold gas spraying (CS). During this process, the respective material, for example in powder form, is applied at high speed. For this purpose, a process gas such as nitrogen or helium heated to a few hundred degrees can be accelerated to supersonic speed, e.g. by expansion. The powder particles of the respective material can be injected into the gas jet, so that they are accelerated to high speed and form a firmly adhering layer upon impact with the base structure.

[0046] Preferably, the base structure or the base volume and the support structure or the additional volume are made of the same material, for example, aluminum or an aluminum alloy. Furthermore, the base and support structures can preferably also be made of different materials. The materials for the base and support structures can each be selected, for example, based on their specific material properties and / or based on specific requirements for the component or based on the specific loads acting on the component.

[0047] Preferably, the basic structure or the basic volume and the support structure or the additional volume are made of similar or dissimilar materials, preferably from different aluminum materials or different aluminum alloys. "Similar" or "same" materials are understood to mean, in particular, materials that have the same or comparable microstructure and / or the same or comparable thermal expansion, which, however, is not the case with "dissimilar" or "unsimilar" materials. Examples of similar materials include different carbon steels. Examples of dissimilar materials include carbon steel and stainless steel due to their different material structures (microstructure and thermal expansion). Similar materials can also include different aluminum alloys, which, due to the variety of possible alloys, lead to significant differences in mechanical and thermal characteristics.For example, the combination of an aluminum material with a (stainless) steel material can be dissimilar, as they are incompatible in many respects. Thus, similar or dissimilar materials with different properties can be used to construct the base structure and the support structure.

[0048] Particularly preferably, the material of the base structure is more resistant to a specific material or less susceptible to wear than the material of the support structure, in particular to mercury. Alternatively or additionally, the material of the support structure preferably has a higher strength than the material of the base structure. If, for example, only the base structure comes into contact with this material during regular operation of the component, the component thus has a high resistance. For the support structure, however, which then expediently does not come into contact with this material, a higher-strength material can be selected in order to achieve a high strength of the component.It is particularly useful to preform the base structure from an aluminum alloy with a low magnesium content, for example, which makes the component highly insensitive to mercury, and to manufacture the support structure from a higher-strength and more easily weldable aluminum alloy, so that a more insensitive component with adapted strength and rigidity can be produced. If the component is intended, for example, for the storage or transport of media containing mercury, the risk of mercury-induced stress corrosion cracking can be reduced. For this purpose, the material of the base structure can be an aluminum alloy, e.g., an AlMg or AlMgMn alloy, with a Mg content of less than 2%. The material of the support structure can be an aluminum alloy with a Mg content of more than 2%.

[0049] The present invention is suitable for a variety of different fields of application and for producing components for various technical devices in process, regulation and / or control technology. In the present context, a technical device is to be understood in particular as a unit or a system of various units for carrying out a technical process, in particular a process, regulation and / or control process. The technical device can advantageously be designed as a machine, i.e. in particular as a device for energy or force conversion, and / or as an apparatus, i.e. in particular a device for substance or matter conversion. Furthermore, the technical device can also be designed in particular as a plant, i.e. in particular as a system comprising a plurality of components, each of which can be, for example, machines and / or apparatuses.

[0050] For example, the component is a component, in particular a component through which fluid flows or through which fluid can flow, for a process engineering device.

[0051] Furthermore, the component can be a component for a pressure vessel or a pressure vessel itself. Such a pressure vessel can be intended, in particular, for storing a substance under positive or negative internal or external pressure. Pressure vessels can be subjected to high pressure cycling. Such a pressure vessel can, for example, comprise a pressure vessel wall, in particular an inner and outer pressure vessel wall, a pressure vessel lid, a pressure vessel bottom, and / or piping. Individual or multiple such elements can be particularly expediently manufactured according to the present method.

[0052] The component can, for example, be a fluid-flow component for a heat exchanger, such as a straight-tube heat exchanger, a plate heat exchanger, or a plate-fin heat exchanger (PFHE), or, for example, a brazed aluminum plate-fin heat exchanger (PFHE; designations according to the German and English editions of ISO 15547-2:3005). Such plate heat exchangers have a large number of stacked separating plates and fins, as well as cover plates, edge strips or sidebars, distributors or headers. Furthermore, pipe sections or pipelines are provided for the supply and discharge of individual media. Such elements can be exposed to high loads during operation of the heat exchanger, e.g., high temperatures or high temperatures.temperature differences as well as high pressures and mechanical stresses, and are therefore particularly suitable for being manufactured according to the present process.

[0053] However, the application of the method according to the invention is not limited to components and process engineering devices through which fluid flows, but is advantageously suitable for a large number of different structural components and technical applications, for example for lightweight construction, aircraft or vehicle construction, etc.

[0054] In addition to the method for producing a component, the present invention further relates to a component for a technical device produced according to the present method. Embodiments of this component emerge analogously from the above description of the method according to the invention.

[0055] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0056] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0057] The invention is illustrated schematically in the drawing using exemplary embodiments and is described in detail below with reference to the drawing. Character description

[0058] Figure 1 schematically shows a heat exchanger in a simplified isometric representation, with individual components of the heat exchanger manufactured according to a preferred embodiment of a method according to the invention. Figure 2 schematically shows a preferred embodiment of a method according to the invention as a block diagram. Figure 3 schematically shows a header of a heat exchanger according to the prior art. Figure 4 schematically shows a header of a heat exchanger manufactured according to a preferred embodiment of a method according to the invention. Detailed description of the drawing

[0059] In Figure 1A heat exchanger is shown schematically and designated 100. The heat exchanger represents a technical or process engineering device, wherein individual elements or components of the heat exchanger 100, in particular its header 7, through which fluid flows, are manufactured in a particularly advantageous manner according to a preferred embodiment of a method according to the invention.

[0060] The Figure 1The heat exchanger 100 shown is a brazed aluminum plate-fin heat exchanger (PFHE; designations according to the German and English editions of ISO 15547-2:3005), which can be used in a variety of systems at a wide range of pressures and temperatures. Such heat exchangers are used, for example, in the cryogenic separation of air, in the liquefaction of natural gas, or in plants for the production of ethylene. It is understood that "aluminum" can also refer to an aluminum alloy.

[0061] Brazed fin-plate heat exchangers made of aluminum are available in Figure 2 of the aforementioned ISO 15547-2:3005 and on page 5 of the publication "The Standards of the Brazed Aluminium Plate-Fin Heat Exchanger Manufacturers' Association" of ALPEMA, 3rd edition 2010. This Figure 1essentially corresponds to the figures of the said ISO standard and will be explained below.

[0062] The Figure 1 The plate heat exchanger 100, shown partially opened, is used for the heat exchange of, in the example shown, five different process media A to E. For the heat exchange between the process media A to E, the plate heat exchanger 100 comprises a plurality of partition plates 4 arranged parallel to one another (referred to as parting sheets in the aforementioned publications, to which the following information in brackets also refers), between which heat exchange passages 1 are formed, each for one of the process media A to E, which can thereby enter into heat exchange with one another.

[0063] The structural sheets with the slats 3 are typically folded or corrugated, with the folds or corrugations forming flow channels, as in Figure 1 of ISO 15547-2:3005. Compared to plate heat exchangers without fins, the provision of structured plates with fins 3 offers the advantage of improved heat transfer, more targeted fluid flow, and increased mechanical (tensile) strength. In the heat exchange passages 1, the process media A to E flow separately from one another, particularly through the separating plates 4, but can possibly pass through the separating plates 4 in the case of perforated structured plates with fins 3.

[0064] The individual passages 1 or the structured sheets with the slats 3 are each surrounded laterally by so-called sidebars 8, which, however, leave free feed and discharge openings 9. The sidebars 8 keep the separating sheets 4 at a distance and provide mechanical reinforcement of the printing chamber. Reinforced cover sheets 5 (cap sheets), arranged parallel to the separating sheets 4, serve as the closure on at least two sides.

[0065] By means of so-called headers 7, which are equipped with nozzles 6, the process media A to E are fed in and out via feed and discharge openings 9. In the inlet area of ​​the passages 1, there are further structured plates with so-called distributor fins 2, which ensure even distribution across the entire width of the passages 1. At the end of the passage 1, viewed in the direction of flow, there may be further structured plates with distributor fins 2, which guide the process media A to E from the passages 1 into the headers 7, where they are collected and withdrawn via the corresponding nozzles 6.

[0066] The structural plates with the fins 3, the further structural plates with the distributor fins 2, the sidebars 8, the separating plates 4, and the cover plates 5 form a cuboid-shaped heat exchanger block 20, whereby a "heat exchanger block" is understood to mean the aforementioned elements without the headers 7 and nozzles 6 in an interconnected state. As in Figure 1 not illustrated, the plate heat exchanger 100 can be formed from a plurality of corresponding cuboid-shaped and interconnected heat exchanger blocks 20, particularly for manufacturing reasons.

[0067] Corresponding plate heat exchangers 100 are brazed from aluminum. The individual passages 1, comprising the structural sheets with the fins 3, the further structural sheets with the distributor fins 2, the cover sheets 5, and the sidebars 8, are each coated with solder, stacked on top of one another or arranged accordingly, and heated in a furnace. The headers 7 and the nozzles 6 are welded onto the heat exchanger block 20 produced in this way.

[0068] In a conventional manner, the headers 7 are manufactured, for example, using semi-cylindrical extruded profiles that are cut to the required length and then welded onto the heat exchanger block 20. The headers 7 are often manufactured with a constant wall thickness, with this wall thickness being based on the position of highest utilization.

[0069] In contrast, the present method enables the cost-effective and material-saving production of Header 7 with a varying wall thickness, which is specifically adapted to the individual load case, as shown below with reference to Figure 2 should be explained.

[0070] Figure 2 shows schematically a preferred embodiment of a method according to the invention as a block diagram.

[0071] The following example explains how a component in the form of a header for a technical device in the form of a heat exchanger is partially additively manufactured using the present method. However, it should be understood that the present invention is not limited to headers and heat exchangers, but is advantageously suitable for a variety of different structural components and technical applications, for example, lightweight construction, aircraft or vehicle construction, etc.

[0072] During the manufacturing process, a planning or simulation phase 210 is first carried out before the component or header is actually manufactured during a manufacturing phase 220.

[0073] In step 211, a simulation of the header to be manufactured, or of the entire heat exchanger including the header, is created using a finite element method (FEM). The header is divided into a finite number of subregions or finite elements of simple form, whose physical or thermo-hydraulic behavior can be calculated based on their simple geometry. The physical behavior of the entire header is simulated during the transition from one element to the adjacent element using predetermined continuity conditions.

[0074] In particular, the FEM simulation takes into account mechanical or thermo-hydraulic loads acting on the header during operation of the heat exchanger, in particular pressures, stresses, etc. The individual finite elements of the FEM simulation expediently represent areas of the wall or walls of the header.

[0075] In step 212, a minimum and maximum required total wall thickness are specified, which the wall of the header should have at least or at most. For example, the total wall thickness can also be specified using a geometric body as a maximum installation space that the header should occupy.

[0076] The minimum required wall thickness is specified, for example, in such a way as to be able to withstand a maximum design pressure, in particular a design, design or calculation pressure, which acts on the wall of the header from the inside or outside during later regular operation.

[0077] Alternatively or additionally, the minimum required wall thickness can be specified in such a way as to be able to withstand loads in areas far away from faults, in particular global faults or external sources of interference, which can exert loads on the header in addition to the design or internal pressure during operation of the header.

[0078] For example, the minimum required wall thickness can be specified according to the standards DIN EN 13445-3 Chapter 7 or ASME VIII-1 Subsec. A UG-27, UG-28, which define the design of the wall thickness of components depending on a permissible design or calculation pressure.

[0079] In step 213, an optimization process, such as a topology optimization, is performed based on the FEM simulation. For example, the overall wall thickness of the header is minimized during the optimization process, with a boundary condition that a specified stiffness of the component should not be exceeded.

[0080] In step 214, as a result of the optimization process, it is determined which of the individual finite elements should be filled with material so that the component has a minimized or optimized overall wall thickness. For example, a first number of the finite elements should be filled so that the header achieves the specified minimum overall wall thickness. In particular, these elements or regions relate to a basic structure of the header. Furthermore, for example, an additional second number of finite elements or regions should be filled so that the header can withstand higher loads occurring at these locations. These regions relate in particular to a support structure by means of which the basic structure is specifically reinforced.

[0081] Based on these results, the header is manufactured during production phase 220. In step 221, a corresponding basic structure or basic volume is first created by manufacturing a wall or wall of the header with a specified wall thickness using a non-additive manufacturing process. For example, the specified wall thickness can correspond to the minimum total wall thickness explained above and specified in step 212. For example, the basic structure can be created by casting or bending.

[0082] In certain areas, the basic structure is reinforced by a corresponding support structure or additional volume. These areas are determined, in particular, by the second number of finite elements explained above. For this purpose, in step 222, a quantity of additional material is applied to the non-additively manufactured wall or the basic structure at these specific areas using an additive manufacturing process.

[0083] Particularly preferred for creating the support structure is the application of a material using wire and arc additive manufacturing (WAAM). Individual layers are created using a consumable wire and an arc, with the material being continuously fed in, for example, in the form of a wire or strip and melted by the arc. Using this type of WAAM process, the additional reinforcement or stiffening volume, and thus the support structure, can be precisely deposited onto the base structure.

[0084] This method thus allows for the targeted application of material to particularly stressed areas of the header using the WAAM process. This allows a simple basic structure to be prefabricated according to the minimum required wall thickness and then specifically stiffened or reinforced, thus adapting it to the specific load case.

[0085] Furthermore, this process enables the targeted use of similar materials with different properties for the construction of the base structure and the support structure. For example, the base structure can be preformed from an aluminum alloy with a low magnesium content. This makes the header mercury-resistant. The support structure, for example, can be manufactured from higher-strength and more easily weldable aluminum alloys. This allows for the creation of a more resistant header with adapted strength and stiffness.

[0086] For example, the first material may be an aluminum alloy, e.g. an AlMg or AlMgMn alloy, with a Mg content of less than 2% and the second material may be, for example, an aluminum alloy with a Mg content of more than 2%.

[0087] Furthermore, it is also conceivable to manufacture the basic structure and the support structure from dissimilar materials or, for example, from the same material.

[0088] Figure 3 3 schematically shows a header 300 of a heat exchanger manufactured according to the prior art. For example, the header 300 has a constant wall thickness and is made of the same material throughout.

[0089] In comparison, Figure 4 A header 400 is schematically shown, which is partially additively manufactured according to a preferred embodiment of a method according to the invention. As can be seen, the header 400 does not have a constant wall thickness, but rather individual wall thicknesses in different regions or finite elements.

[0090] The header 400 according to the present method can thus be manufactured more cost-effectively and with less material consumption than the conventional header 300 according to the prior art.

Claims

1. Method for producing a component (7, 400) manufactured in part additively for a technical device (100), wherein a basic structure of the component (7, 400) is manufactured (221) with a predefined wall thickness by means of a non-additive manufacturing method, wherein at least one region of the component (7, 400) is determined (213) by means of an optimization method, wherein, in the at least one region, a supporting structure is applied (222) to the basic structure by means of an additive manufacturing method.

2. Method according to claim 1, wherein the predefined wall thickness of the basic structure is predefined on the basis of a minimum required wall thickness or as this minimum required wall thickness in order to be able to withstand a maximum design pressure.

3. Method according to either claim 1 or claim 2, wherein, in the course of the optimization method (213), an optimized wall thickness is determined for the at least one region, and wherein the supporting structure is applied (222) to the basic structure in the at least one region on the basis of the optimized wall thickness by means of the additive manufacturing method.

4. Method according to any of the preceding claims, wherein, in the course of the optimization method (213), an adaptation of a locally required wall thickness of the component (7, 400) is carried out on the basis of loads acting on the component during operation.

5. Method according to any of the preceding claims, wherein a total wall thickness in the at least one region, composed of the predefined wall thickness of the basic structure and a thickness of the supporting structure, is determined in the course of the optimization method in order to be able to withstand a load acting on the component in the at least one region during operation.

6. Method according to any of the preceding claims, wherein, in the course of the optimization method (213), a stiffness of the component (7, 400) and / or a maximum occurring stress in the component (7, 400) and / or a geometric constraint are taken into account as a constraint.

7. Method according to any of the preceding claims, wherein, in the course of the optimization method (213), a topology optimization and / or a material optimization and / or a load optimization and / or a stress optimization and / or a flow optimization and / or a geometry optimization of the component (7, 400) is carried out.

8. Method according to any of the preceding claims, wherein the optimization method (213) is carried out on the basis of a simulation (211) of the component (7, 400), in particular the technical device (100) comprising the component (7, 400), in particular by means of a finite element method (211).

9. Method according to any of the preceding claims, wherein the supporting structure is applied to the basic structure in the at least one determined region by means of arc wire deposition welding (222) and / or selective laser sintering and / or selective laser melting and / or electron beam melting and / or stereolithography and / or fused deposition modeling and / or by means of cold spraying.

10. Method according to any of the preceding claims, wherein the basic structure and the supporting structure are manufactured from the same material or from materials of similar type or from materials of dissimilar type, in particular from different aluminum alloys.

11. Method according to any of the preceding claims, wherein the material of the basic structure is more resistant to a specific material, in particular mercury, than the material of the supporting structure, and / or wherein the material of the supporting structure has a higher strength than the material of the basic structure.

12. Method according to any of the preceding claims, wherein the basic structure of the component is manufactured by means of a non-additive primary forming method, in particular casting or pressing, and / or by means of a non-additive forming method, in particular bending or rolling, and / or by means of a non-additive joining method, in particular welding, soldering or gluing, and / or by means of a non-additive separation method, in particular machining or cutting.

13. Method according to any of the preceding claims, wherein the component (7, 400) is a component for a technical device (100), in particular a component for a pressure vessel, in particular a pressure vessel wall, a pressure vessel lid, a pressure vessel base or a pipeline, or a component through which fluid flows for a heat exchanger (100), in particular a partition plate, a lamella, a cover plate, an edge strip, a distributor or a pipeline.

14. Method (7, 400) according to any of the preceding claims, wherein the component manufactured in part additively is designed as a component (7, 400) for a pressure vessel, in particular as a pressure vessel wall, a pressure vessel lid, a pressure vessel base or a pipeline, or as a component through which fluid flows for a heat exchanger (100), in particular as a partition plate, a lamella, a cover plate, an edge strip, a distributor or a pipeline.