WO2022106564A9

WO2022106564A9 - Process for producing foam bodies

Info

Publication number: WO2022106564A9
Application number: PCT/EP2021/082195
Authority: WO
Original assignee: Vincador Holding Gmbh
Priority date: 2020-11-19
Filing date: 2021-11-18
Publication date: 2023-02-23
Also published as: WO2022106564A1; DE102020130583A1

Abstract

The invention relates to a process for producing a three-dimensional foam body, the foam body consisting of an open-pored or closed-pored foam structure and comprising cavities which communicate with one another and/or with the environment or cavities which are closed from one another and/or from the environment.

Description

Process for the production of foam bodies

The invention relates to a method for producing a three-dimensional foam body. A further aspect of the invention is a foam body, a use of the foam body and a data set for a production facility for the production of a foam body. The invention is aimed in particular at the production of foam bodies and foam bodies with an open-pore foam structure, which accordingly have a large number of cavities which communicate with one another and/or with the environment, or a closed-pore foam structure in which the large number of cavities are separated from one another and/or or are closed off from the environment.

Various production processes are already known for the production of foam bodies, which, according to this description, should be understood as meaning foam materials with a predefined geometry for an end product or foam materials which are intended as semi-finished products for later cutting. In these previously known manufacturing processes, a starting material in a formable state, usually in a liquid or pasty state, is placed in a mold, with an extrusion process or an injection molding process being used for shaping, for example. The starting material undergoes a foaming process before, during or after shaping. This foaming process can be induced chemically or thermally, for example, and causes gas formation in the starting material. Alternatively, a gas can already be used during the Shaping process are mixed with the starting material and thereby cause the foaming process. As a result of this gas formation or gas admixture, a large number of cavities are produced in the starting material and this state is stabilized by solidifying (hardening) the starting material.

Foam bodies produced in this way are characterized by elastic or viscoelastic properties. The cavities essentially have the same volume, but actually produced foams have cavities that differ slightly from one another in terms of their volume and shape due to the uncontrolled nature of the chemical reaction process or the blowing in of gas. Typically, the cavities have a spherical, ideally ball-shaped, geometry, but the stresses and strains that occur during shaping can also produce cavity geometries that deviate from this. The pores or cavities of known foam bodies are delimited by wall structures which, as a whole, surround the cavity in a closed manner or which have openings through which adjacent cavities of a foam are connected to one another. These wall structures arise randomly from the starting material during the shaping process due to the foaming process and the hardening of the starting material.

Foam bodies of this previously known type can be produced with different material properties that are desired in each case by selecting the starting material and the parameters during the shaping process and selecting the gas that may be added. The material properties can be set for a specific starting material in specific, limited areas. However, certain conflicting goals, for example with regard to the density of the foam body and its strength, elasticity and hardness, can only be set within certain limits.

In addition, foam bodies with special properties in this regard can often only be produced from reaction-crosslinking polymer starting materials. Such reaction-crosslinking polymer foams are only insufficiently recyclable, since they cannot be recycled with new shaping with the aim of producing a solid or foam body with the original properties of the reaction-crosslinked polymer. Therefore, only secondary uses with reduced quality requirements for the recycled material or purely thermal utilization can be considered as recycling, which is not sufficient for products with high demands on environmental compatibility. There is therefore a need for foams that combine high quality requirements with good recyclability.

In addition, foam bodies are often required with locally different mechanical properties. For example, it is advantageous for mattresses or seat cushions to provide a higher degree of hardness in some specific areas than in other areas in order to improve the lying or sitting comfort for the user. For this purpose, it is known to combine foams from different shaping processes into a foam body in a subsequent production step, in order to combine these different properties locally differentiated by the different foams in the foam body. It is also known to change the foaming parameters during the shaping process in order to achieve locally different foam properties. Although foam bodies with locally different properties can be achieved with these production methods, the production process is complex on the one hand and limited in terms of local differentiation and the design options for the properties due to large mechanical differences and in terms of the spatial resolution of the differentiation. There is a need to improve these possibilities.

From JP2020-172076A a seat cushion and a seat back with integrated ventilation ducts are already known, which are produced in a 3D printing process. The seat cushion and the seat back have an internal skeleton structure in which the ventilation ducts are integrally formed. This skeleton structure is placed on a frame structure and wrapped in an upholstery fabric. The disadvantage of this design and production method, however, is that a comprehensive definition of the skeleton structure over the entire volume of the seat cushion or seat backrest is required in the production data and therefore with the currently available computing power of the work planning computer and the production computer used in a 3D printing process only a rough skeleton structure can be realized and the comfort properties of a conventional foam cannot be achieved as a result.

According to the invention, the above problems are solved with a method for producing a three-dimensional foam body, the foam body consisting of an open-pore or closed-pore foam structure and corresponding cavities communicating with one another and/or with the environment or cavities closed off from one another and/or from the environment, which comprises the steps comprises: production of a multiplicity of foam cells by inserting cell structural elements which have a cell cavity at least partially enclosing, built up by means of an additive manufacturing process, and establishing a connection between the cell structure elements of the foam cells by means of the additive manufacturing process.

According to the invention, the foam is not produced by mixing gas and a liquid plastic material with subsequent curing/crosslinking of the plastic material including the gas components in a process in which the gas is added to the liquid plastic material by mixing or the gas is added to the plastic material caused by a chemical or physical reaction and the foaming is generated as a result. According to the invention, a mixing process of gas and plastic or a gas outgassing process from the plastic for the production of the foam structure is therefore dispensed with.

Instead, the invention takes a completely different approach. An additive manufacturing process is used to produce the solid part of the foam. Such an additive manufacturing process should be understood to mean all manufacturing processes that have also become known under the term additive manufacturing process (or also under the old term “rapid prototyping”), which are characterized by the fact that the inner and outer geometry of the product to be manufactured is defined before the manufacturing process electronic data is predetermined, for example by means of an STL data interface or in file formats such as VRML, OBJ, AMF, 3MF, CLI or SLC or in other proprietary data formats. Geometry information and often additional information on material, color or the like is stored in such file formats and can be used to control an additive manufacturing device - for example in the form of the digital definition of cross sections through the product to be manufactured, which shows the respective geometry of the product in the Define a cross-section of electronic data. Based on this data, a mouldable, chemically or physically hardenable material is then hardened at points or selectively in layers (cross-sectional areas) and the product is built up successively by building up several selectively hardened areas or in several layers. The selectively cured layers or specific areas of the product are connected to one another.

The electronic data is created as part of a design or planning process, for example using CAD software, and defines the geometry and gfs. the material of a component to be manufactured. This electronic data is typically available as vector graphics-based data, and they are typically used here converted into a production data set in a data processing step preceding additive manufacturing, with which the additive production system is controlled. In this production data set, the individual areas of a layer to be hardened are defined for each layer of the component to be built up in layers in a data set that is typically based on raster graphics, and the additive manufacturing process can then be controlled using this production data set. The production data set can define further parameters in a spatially resolved manner, for example the power of an energy beam such as a laser power, a traversing speed and the like.

In principle, additive manufacturing processes have become known, for example, in which a powder bed, in which thin layers of powder are applied one after the other, and after each layer is applied, the layer is replaced by a selectively acting high-energy beam or by selectively applied hardener components or hardener inhibitors according to the cross-section of the respective product in this layer be cured. In other additive manufacturing processes known as stereolithography, photopolymerizable plastics are used, which are available as liquid plastic and by lowering a construction platform into such a liquid bath, a thin liquid layer can be selectively cured from above with selectively masked irradiation or by scanning using a high-energy beam , wherein an inverse principle with raising the construction platform in a liquid bath and irradiation through a window at the bottom of the container in which the liquid is located is also known. Another common additive manufacturing process is what is known as three-dimensional printing, in which a hardenable material is selectively dispensed from a print head onto a construction platform and this selective application on the construction platform builds a three-dimensional product by controlling the position of the print head based on the product data . The hardenable material used here can be used as a single-component material or as a multi-component material with components that react with one another. In addition, with this method there is the possibility in a simple manner of dispensing different materials or differently colored materials from the print head and thereby constructing a product which is composed of different materials in different areas or is differently colored.

According to the invention, the foam is produced using the additive manufacturing process, specifically in that the solid material components of the foam, ie those volume components that are not filled with gas, are produced using the additive manufacturing process. The volume fractions of the foam body that are not filled with hardened material by the additive manufacturing process in this production are subsequently the gas-filled volume fractions of the foam body - either because no material is already placed here in the additive manufacturing process, or because material is present in these volume fractions during the additive manufacturing process is not cured and can therefore subsequently be removed from the additively manufactured component, for example by tipping out, vacuuming or the like.

According to the current state of the art, structures with a minimum wall thickness of approx. 0.5 to 1 mm can be produced using additive manufacturing processes. The minimum limit that can be achieved depends on the principle of the additive manufacturing process. Due to the increasing improvement of the processes, the available beam optics and the starting materials, it can be expected that the resolution during production will be further reduced in the future and that structures with even smaller dimensions can also be produced additively. However, even with the dissolving options available today, it is possible to produce a foam structure suitable for practical purposes without any problems.

In the simplest case, the inner geometries of a conventionally produced foam can be simulated by describing the solid volume fractions of such a foam using geometric data and using this geometric data to control the additive manufacturing process in order to produce the foam structure additively in this way and to add the foam directly or through a thereby generating subsequent removal process of uncured material. It should be understood that for many applications, standardization and/or scaling of the original geometry of a foam cell of the foam into a uniform foam cell or an enlarged dimension of the foam cell, for example by doubling or tenfold the pore volume, for the relevant mechanical properties of the foam are of no importance or even advantageous and the production of the foam in the additive manufacturing process can thus extend to a large number of additive manufacturing processes and broad fields of application of the foam.

The foam body according to the invention comprises a multiplicity of foam cells, a foam cell being understood to mean a cavity and a solid structure surrounding the cavity. The solid structure consists of cell structure elements, which can be wall sections, beam-like structures, lever-like structures and be the like that are straight or curved. The cell structure elements can enclose the cavity tightly or can allow the cavity to communicate openly with neighboring cavities, ie not enclose it in a sealing manner. In principle, a cell structure element can also separate two or more adjacent cavities from one another, that is to say it can be formed integrally as a cell structure element for these adjacent cavities.

The foam body according to the invention or the foam body produced using the method according to the invention preferably achieves a compression hardness greater than 2 kPa, greater than 3 kPa and preferably greater than 5 kPa and less than 20 kPa, less than 15 kPa and preferably less than 13 kPa according to DIN EN ISO 3386-1 is.

In addition to the - possibly standardized - imitation of the inner structure of conventional foams, it is particularly advantageous that the production method according to the invention can also be used to produce foams whose inner geometric structure can be built up in a planned and targeted manner by additively adding the cell structure elements in a predetermined manner using the production data are produced and as a result a geometry that is advantageous for the properties of the foam--in particular with regard to its orientation, its course and its wall thickness--is obtained and the disadvantages of the erratically produced internal structure of conventional foams are thereby avoided. In this way, for example, foam bodies can be produced with the method according to the invention, which have direction-dependent mechanical properties, i.e. behave differently in a first spatial direction with regard to elasticity and/or strength than in a second, deviating spatial direction. In particular, foam bodies can also be produced whose mechanical properties differ in all three mutually perpendicular spatial directions.

The construction of the foam body from foam cells makes it possible to carry out the method according to the invention with the following steps for creating a production data set:

Definition of at least one, preferably several volume areas of the foam body based on boundary surfaces of the respective volume area in a design data set,

Definition of a foam cell type to be formed in the respective volume area in the design data set Creation of the production data record for the foam body based on this definition of the boundary surfaces and the respective foam cell type.

The production data record can be in the form of vector graphics data, ie data that describes a geometry of a body based on definitions of geometrically superordinate structures such as corner points, axes, radii. Such vector graphics data are used, for example, in CAD construction. The manufacturing data record can also include STL data, which is a data structure that describes a geometry of a body using corner points of triangular surfaces.

The production data record is typically data that defines the areas to be cured point by point for each layer of the body to be built up in layers in such a way that a laser or print head used for curing, for example, moves to each of the points defined in the production data for the layer in the respective layer. The order in which these points in the respective layer are approached follows a scanning strategy that is usually optimized to achieve rapid curing in the respective layer and to produce an overall distortion-free product with good-quality surfaces. The manufacturing parameters of the manufacturing process (e.g. the irradiation intensity, the focusing or the exposure time of a laser) are therefore often controlled individually using the manufacturing data set and are accordingly also defined therein, so that a final surface of the product is manufactured with different manufacturing parameters than surfaces on which the subsequently produced layer of the component again material is applied and cured, or so that the lower surface of an overhang on the product is produced with different manufacturing parameters than an upper surface of the product.

The production data record for the entire foam body can be calculated from the design data record in a data processing operation that precedes the start of additive manufacturing. Alternatively, it is also possible to precalculate the production data set for only a partial area of the foam body before the beginning of the additive manufacturing and then to calculate the production data set for this (these) further partial area(s) from the design data set for one or more partial areas of the foam from the design data set during the ongoing additive manufacturing to be calculated and supplemented accordingly or to be processed as a partial production data record. A partial area can preferably correspond to one or more layers of the additive manufacturing process, provided that the additive manufacturing process builds up the foam layer by layer. The calculation In this way, the production data record can run so far ahead of the currently executed additive production step that only one production data record of the respective layer to be produced additively or a number of two, three or more layers to be produced additively in each case is calculated in advance from the design data and thereby the quantity of the in data to be processed in one computing step and the required data size and memory size is significantly reduced.

This saves considerable computing power, since the inner volume defined by the boundary surfaces can now be filled with foam cells of the defined type in the production step. The step from a vector graphics-based geometry definition in the design data record to a raster graphics-based representation in the production data record can be carried out in a simple way of conversion, since not every individual structure in the design data has to be defined separately, but this using a vector graphics-based specification of one or more uniform geometric structures and an indication of the repetition of this uniform geometric structure within a component volume of the entire foam body or of sections of the foam body (in the case of areas with different compressive strengths within the foam body) can be defined using vector graphics-based specification. In addition, with the method according to the invention, the conversion of the design data set into a production data set can be carried out in sections, for example in a production process computer controlling additive manufacturing, so that a preliminary calculation and gfs. transmission of large amounts of data, as with conventional methods, is avoided.

This implementation therefore enables the total volume of the foam body to be defined in the design data set when the production data set is created using an algorithm that defines the multiplication and juxtaposition of the foam cells of the corresponding type and executes them within the boundary surfaces. As a result, a separate definition of the material components of the foam body to be produced in the additive manufacturing process, which is intensive in terms of computing and storage space, can be avoided. The method according to the invention hereby enables the size of an individual foam cell to be reduced to such an extent that it can be inscribed in a sphere with a diameter of less than 5 mm, preferably less than 4, 3, 2 or even 1 mm and thereby a foam body can be manufactured with excellent spatially resolved padding and damping properties, the outer dimensions measurements of more than 5cm x 5cm x 5cm and yet the necessary data processing steps are carried out on currently available, conventional computers for construction planning and production control.

According to a first preferred embodiment, it is provided that the additive manufacturing method is selected from: a 3D printing method, a stereolithography method, a selective laser sintering/laser melting method, binder jetting, fused deposition modeling, polyjet method, digital light processing, HP multijet fusing . These different printing processes are characterized by different processes, materials that can be used and resolution accuracies. They are therefore suitable for producing foams from different materials such as plastics, metals or ceramic materials, producing open-pore or closed-pore foams and additively producing the foams with a desired resolution and size of the cell structure elements.

Furthermore, it is preferred if the cell structure elements are made of a material selected from: an elastomeric material, a thermoplastic elastomeric material, a polyurethane, in particular thermoplastic polyurethane, a polyvinyl chloride or a polymer with a Shore A hardness of at least 50, 60, 70 or 80 and not exceeding 90 or 100. Compared to conventional foam production methods, the production method according to the invention opens up a wide range of materials to be processed, since miscibility with a gas or a gaseous phase produced in a chemical process does not have to be taken into account. In this way, on the one hand, materials can be selected that have a specific hardness, elasticity, and strength, in order to thereby influence the properties of the foam in a desired direction with regard to these mechanical parameters. On the other hand, a large number of materials are available for the production of foams using the process according to the invention, which have better properties in terms of their recyclability and environmental compatibility than materials for conventional foam production. For example, thermoplastics can be used, which enable the foam material to be recycled at the end of its useful life and thus be available for full reuse of the material.

According to a further preferred embodiment it is provided that the geometry of the cell structure elements of the foam body is defined by digital planning data before the additive production of the cell structure elements and from the digital planning data Manufacturing data set is created with which the additive manufacturing process is controlled. According to this embodiment, the geometry of the cell structure elements and their arrangement, course, material thickness and other geometric properties are determined in advance in a digital planning process. This procedure, which is necessary for the additive manufacturing process, makes it possible to build up the foam either with a uniform geometry of the cell structure elements over its entire volume, or, depending on the requirements, to plan and subsequently produce it in two or more areas with a different geometry of the cell structure elements. This production of the foam, which is controlled on the basis of defined geometric data, consequently enables a targeted provision of properties of the foam, which can be resolved and predefined according to location and direction.

It is further preferred that at least two foam cells, preferably more than twenty or one hundred foam cells of the foam body are geometrically identical. A foam body is usually characterized by a very large number of foam cells, which are very similar in the conventional manufacturing process due to the production method, but ultimately can also differ slightly from one another. In contrast, it is possible with the production process according to the invention due to the defined and exact production method to build up the foam cells completely identical to one another and thereby to achieve homogeneous properties of the foam even on a microscopic level of two individual or several adjacent foam cells or all foam cells. This achievable identity of the foam cells in the foam body can be adjusted using the production method according to the invention and characterizes a foam that was produced using the additive production process according to the invention.

It is even more preferred if the foam body has a first foam body section with a first type of foam cells and a second foam body section with a second type of foam cells that is different from the first type. As explained above, the digital planning of the geometric structure of the foam cells and cell structure elements in advance also makes it possible for the foam body not to be built up exclusively from identical foam cells, but also to produce a different geometry of the foam cells in one area than in another area or more than 2, for example 3, 4, 5 or more than 5 areas with different geometries of the foam cells are produced. In this way, three-dimensional foam bodies can be produced that behave mechanically differently in different areas and thus have the desired usage properties in these areas have areas. The different types of foam cells can also be arranged alternately over the entire foam body adjacent to one another or in any other way alternately, for example by layers with different types of foam cells being built up alternately on top of one another in order to achieve progressively or degressively running mechanical properties perpendicular to the plane to achieve these layers of the foam body.

It is particularly preferred that only foam cells of the first type are arranged in the first foam body section and/or that only foam cells of the second type are arranged in the second foam body section. According to this development, the two different foam body sections differ in that only foam cells of the first type are arranged in one foam body section and only foam cells of a second type are arranged in the other foam body section. This distinction between the two foam body sections is often preferred over alternative configurations in which, for example, the percentage ratio of two foam cell types in one section is selected differently than in the other section.

Different types of foam cells can be understood as meaning foam cells whose cell structure elements differ in terms of their course, their wall thickness or their orientation relative to one another, or foam cells that differ from one another in terms of their dimensions in one, two or three spatial directions.

It is even more preferred if the first and the second type of foam cells are formed by cell structure elements whose arrangement and course is the same and that the wall thickness of a cell structure element differs in an arrangement and a course in relation to a foam cell of the first type of the wall thickness of a cell structural element in the same arrangement and course with respect to a foam cell of the second type. According to this embodiment, the cell structure elements in the two or more differently designed sections do not differ in terms of the course and orientation of the cell structure elements, but only in terms of the wall thickness of the cell structure elements. This construction of a foam with two or more different sections is on the one hand efficient in planning in the digital data preparation of the manufacturing data for the additive manufacturing process; directional properties in the different sections differ only in terms of height, but not in their direction of mechanical properties. In addition, by changing the wall thickness, the connection between two different sections can be produced in a mechanically reliable and resilient construction, since the cell structure elements of the foam cells in the interface area of the two foam cells do not differ geometrically from one another, but only a change in wall thickness has to be implemented in the interface area.

It is further preferably provided that interface foam cells are arranged in the interface area between the first area with the foam cells of the first type and the second area with the foam cells of the second type, which differ neither in the course nor in the alignment of the cell structure elements from the foam cells of the first and of the second type, which, however, have a first wall thickness in the border area to the foam cells of the first type, which corresponds to the wall thickness of the cell structure elements of the first type and which have a second wall thickness in the border area to the foam cells of the second type, which corresponds to the wall thickness of the cell structure elements of the second type and which is different from the first wall thickness. In this way, these interface foam cells form the connection between the foam cells of the first and second type and make it possible for both the foam cells of the first and second type and the interface foam cells to differ only in the wall thickness of the cell structure elements, but not in their length, orientation and arrangement. The digital data can therefore be created by multiplying a single foam cell model, and in order to allocate different compressive strengths in two or more areas, the foam cells in the respective areas are assigned different wall thicknesses. The connection between the foam cells is uniform throughout the foam and therefore the definition of the interfaces between the areas of different compression stresses is efficient when creating the production data.

It is further preferred if each of the foam cells of the first type is formed by at least two different cell structure elements which differ in wall thickness. These cell structure elements with different wall thicknesses are preferably aligned in different spatial directions. In this way, an anisotropic mechanical behavior is provided by the foam cell of the first type, ie for example a first compression hardness in a first spatial direction and a different second compression hardness in a different second spatial direction. In this embodiment, too, the first and second and optionally further areas and the interface can be constructed from foam cells whose cell structure elements do not differ in terms of their orientation, arrangement and length, but only in the wall thickness of the cell structure elements. This in turn makes it possible to produce foams with anisotropic mechanical behavior in one area or in two or more areas of foam cells that differ from one another in terms of anisotropy in an additive process and to carry out efficient planning of the digital data.

The aforementioned different mechanical properties of the foam cells, isotropic or anisotropic, can be provided in two defined volume ranges. Alternatively, it is preferred to provide a gradual progression of the mechanical properties by changing the wall thickness of the cell structure elements of the foam cells gradually over a region of several adjacent foam cell layers, for example by providing a different wall thickness from layer to layer or by changing the wall thickness after every two , three or more layers changes.

It is further preferred if the surface layer of a foam body is produced from foam cells which are different from the foam cells in the interior volume region of the foam body. Here, the surface layer can comprise a single layer of foam cells or several such layers. With this embodiment, a denser surface or a surface with a higher compressive strength or a higher density can be provided than in the inner volume area of the foam body. In particular, the foam cells can have several or exclusively closed outer surfaces on the surface of the foam body. This provides a dense or selectively porous surface of the foam body, which can be designed, for example, in the manner of a patterned upholstery cover and ensures uniform breathability through the surface of the foam body.

It is even more preferred if the foam body comprises foam cells or consists of foam cells which have the geometry of an Archimedean body. Archimedean solids are regular convex polyhedra with the following properties:

(i) their faces are regular polygons, (ii) all vertices of the body are related to each other in exactly the same way (uniformity of vertices), and

(iii) they are neither platonic solids nor prisms nor antiprisms.

Such Archimedean bodies have proven to be particularly suitable because of their geometry, because they can be lined up in a favorable manner and connected to one another at their points of contact or can be made integral in order to build up a three-dimensional foam body that consists of a large number of such Archimedean bodies as foam cells consists of or includes. It should be understood here that the wall sections delimiting the Archimedean body in the conversion into a foam cell can also be formed by cell structure elements which simulate this wall surface. Likewise, the Archimedean body can also be formed as a foam cell, in that only the edges of the Archimedean body are reproduced as a cell structure element. In this case, the cell structure element takes on a strut-like shape with nodes in the areas where two or more edges of the Archimedean body meet meet.

As an alternative to this embodiment, the foam cells can also be formed by modified Archimedean solids in which one of the three aforementioned conditions (i)-(iii) is not met.

It is particularly preferred if the foam cells are selected from: polyhedrons, truncated polyhedrons, or Archimedean solids which have plane-parallel surfaces in all three spatial directions, for example a truncated octahedron or a cubotahedron. Here and in the following, a truncated polyhedron shape is to be understood as meaning a shape which, starting from the polyhedron, can have a truncated section to form a truncated section at any truncated height. These foam cell geometries have proven to be particularly favorable for the production of foams, because with these geometries of a single foam cell, the connection of adjacent foam cells to form a coherent foam body can be efficiently planned in the digital preparation of the production data and leads to a resilient foam structure with the desired foam properties.

It is even further preferred if the foam body comprises foam cells or consists of foam cells, which are delimited by planar geometric surfaces Surface edges abut and that the cellular structural elements of a foam cell extend as a beam or strut along some or all of the edges of the foam cell. According to this embodiment, the method according to the invention can be implemented with a large number of foam cell geometries, including in particular Archimedean solids or modified Archimedean solids. The mechanical properties of the foam are created by creating beam or strut structures that extend along the edges of the foam cells. The result of this manufacturing process is an open-pored foam body whose properties can be influenced efficiently and in a planned and desired manner by the geometry of the foam cells and the wall thickness of the beam structures.

In principle, it should be understood that the cell structure elements of the individual foam cells can be isolated and can be connected to one another at certain points in order to achieve the connection of the foam cells to form a foam body. It is even further preferred if a foam cell comprises a top cell structure element surface, a bottom cell structure element surface and side cell structure element surfaces, and that the top cell structure element surface of a cell is integral with the bottom cell structure element surface of an overlying adjacent foam cell, the bottom cell structure element surface of a cell is integral with the top cell structure element surface of a underlying adjacent foam cell, and/or a lateral cell structural member face of one cell is integral with a lateral cell structural member face of a laterally adjacent foam cell. According to this embodiment, the foam cells of the foam body are integrally connected to each other in such a manner as to share side faces, top faces or bottom faces by integrally forming the cell structure members constituting these cell structure member faces for adjacent foam cells. A cell structure element thus represents a boundary for two or more foam cells adjoining one another in the area of the cell structure element, as a result of which an overall integral structure of the foam cells of the foam body is achieved. The foam body is then presented as a coherent lattice structure, with the lattice structure elements being formed by the cell structure elements and each enclosing cavities which then represent a foam cell with these cell structure elements. This integral formation of the cell structure elements can take place on all sides including the top and bottom of a foam cell, but it can also be implemented only on certain sides or only on the top or only on the bottom.

A further aspect of the invention is a foam body comprising a multiplicity of foam cells which are formed by a cell structure surrounded by elements Cavity in which the cell structure elements are produced using an additive manufacturing process. The foam body according to the invention is characterized in that it comprises foam cells or is formed from foam cells which comprise a cavity surrounded by cell structure elements and the cell structure elements of the foam body are produced in an additive manufacturing process. As shown above, such a foam body is characterized on the one hand by the fact that the cell structure elements have a geometrically exact pattern due to the exact digital advance planning of their geometry, in contrast to conventional foams, there are usually several completely identical foam cells in the foam or the Foam is even constructed entirely or in sections from completely identical foam cells or includes them. The foam according to the invention is further characterized in that the cell structure elements have a surface and inner material structure corresponding to the additive manufacturing process—in particular, the point-by-point or layer-by-layer production of the cell structure elements is depicted and verifiable in their material structure.

The foamed body according to the invention can be developed in that the cell structure elements have a size that fits into a spherical body with a diameter of less than 5 mm. Such an inscribed cell structure element typically has essentially similar dimensions in all three spatial directions. According to this development, the foam body is made up of cell structure elements that do not exceed a certain size. In particular, this size can be selected in such a way that a sphere circumscribing the foam cell has a diameter of not more than 5 mm. In certain applications, this ball can also have a maximum size of 6, 7, 8, 9, 10 or 15 or 20 mm. Furthermore, it is advantageous in certain embodiments if the sphere circumscribing the foam cells has a diameter of no more than 4, 3 or 2 mm. In principle, it should be understood that foam cells with different geometries can also be formed in a foam body according to the invention. In this respect, these foam cells can also be circumscribed by a sphere that has a minimum diameter according to one of the values mentioned above and a maximum diameter according to one of the values mentioned above, for example foam cells that can be divided into a sphere with a minimum diameter of 2 mm and a maximum diameter of 8 mm are inscribed include. Despite this small size of the individual foam cell, it is possible with the method according to the invention to produce foam bodies with external dimensions that are larger than 5 cm×5 cm×5 cm in an additive manufacturing process. Alternatively, cell structure elements can also be used which have different dimensions in one spatial direction, in particular by an order of magnitude, from the dimensions in the other two spatial directions and which therefore fit into a spherical, elongated enveloping body, for example, or into an elongated cuboid shape. This can be used to create cell structure elements with direction-dependent foam structure properties.

It is even more preferred if the foam body comprises a first section comprising or consisting of foam cells of a first type and a second section comprising or consisting of foam cells of a second type different from the first. With regard to this embodiment, reference is made to the above description of the production of a foam body with two or more different sections.

It is even more preferred if the cell structure elements consist of an elastomeric material. An elastomeric material is understood here to be an elastomeric plastic which, in terms of material differentiation from plastics, is therefore not a duromer with essentially hardly any geometrically relevant deformation properties. The elastomer can in particular also be a thermoplastic elastomer in order to enable material recycling of the foam after its service life.

According to a further embodiment of the foam body according to the invention, it is provided that one or more functional components are arranged in the foam body or on the outer surface of the foam body, which are preferably produced in the same additive manufacturing process as the foam body, and are in particular selected from: fastening sections for fastening the foam body to another component or for attaching other components such as sensors to the foam body, integrated channels, in particular for ventilation or for a cold or heat fluid, a closed or apertured outer surface layer of the foam body, in particular a seat layer, the mechanical properties of which depend on the properties of the interior of the foam body is different, damping elements that have an energy-absorbing behavior through internal friction or friction of two structural elements together, especially for shoes / shoe soles, integrated loudspeakers, including lines for their power supply, integrated light sources, including lines for their power supply. According to this embodiment, not only are the foam cells of the foam body produced in the additive manufacturing process, but at the same time functional elements, sections or components are also integrated into the foam body or produced on its outer surface using appropriate production data created digitally in advance. On the one hand, these functional elements can serve to conduct fluids, for example in order to achieve a desired temperature control effect for a user of a seat or a mattress, which represents the foam body, by means of cool or heated air. Furthermore, functional elements such as damping elements, loudspeakers, lighting devices can be integrated into the foam body and produced in the additive manufacturing process. As a result, the properties of the foam body and its function are further developed and adapted to specific purposes. Electrical supply lines, which serve to supply such active functional elements in the foam body with energy, can also be produced during the additive manufacturing process. Such functional elements can be, for example, a cable duct, an assembly cavity, an access slot that allows reversible expansion to access an assembly cavity, air ducts, air guiding elements, air distributors, air openings, locking elements, assembly elements such as clips, screw openings, skeleton structures with increased rigidity compared to the foam, air cushions with Be air supply lines for massage functions.

The foam body according to the invention can particularly preferably be characterized in that it has properties produced by the previously explained production of the foam body in an additive manufacturing process. Accordingly, the foam body can therefore comprise two or more different areas with different types of foam cells. The cell structure elements of the foam cells of the various types can differ from one another in terms of wall thickness and can be consistent in terms of orientation, arrangement and length. Interface foam cells can be provided, which have a wall thickness of the cell structure elements that matches a first type on one side and a second type on the other side. The foam cells can have anisotropic properties in that cell structure elements that run in a first direction have a different wall thickness than cell structure elements that run in a different direction. Gradual progressions of the compression hardness in the foam body can be provided by changing the wall thickness of the cell structure elements from layer to layer or every two, three or more layers, in particular increasing or decreasing them gradually. The foam body can also have foam cells on its surface with specific properties that differ from the properties of the foam cells inside Volume of the foam body are. For example, the surface foam cells can have a greater wall thickness of the cell structure elements or have partially or completely closed foam cell surfaces in order to set a specific air permeability as a result.

Another aspect of the invention is a method for generating the manufacturing data set for the production of a foam body in an additive manufacturing process, with the steps: (i) defining the outer boundary surfaces of the foam body in a vector-based digital planning program and creating a first planning data set from the specified outer boundary surfaces , (ii) determining the geometry of a cell structure element in the vector-based digital planning program and creating a second planning data record from the geometry of the cell structure element, (iii) creating a manufacturing data record, which includes manufacturing data for an additive manufacturing process of the foam body, from the first and second planning data record by the volume defined by the first planning data set, which is enclosed by the outer boundary surfaces, is filled with a large number of cell structure elements lined up in a row, each of which has a geometry according to the second planning data set. This process solves the special problem associated with the additive manufacturing of foams that digital, vector-based planning programs, i.e. typically CAD design software and the hardware on which such programs are run, are not designed and dimensioned to handle the large number of surfaces , to process edges and vertices that result from the large number of cell structure elements contained in a foam body. Therefore, the process for data creation deviates from the known procedure and does not create all geometric structures in the vector-based digital design phase, but only the surfaces bounding it to define the geometry of the foam body, on the one hand, and the geometry of a single cell structure element on the other. The geometric data from the two planning data sets created in this way, which can also be combined integrally in one planning data set, then form the basis for creating the production data set. This manufacturing data record contains the geometric data required to additively manufacture all structures of the foam body in a spatially resolved manner. Depending on the additive manufacturing method, this manufacturing data can group the spatial resolution layer-by-layer or point-by-point, for example. The conversion from the planning data records into the production data record takes place with the requirement that the volume of the foam body delimited by the area is completely built up or filled with cell structure elements whose geometry is in is defined in the second planning data record. In order to carry out this transformation from the planning data records into the production data record, a data specification can also be made that describes how the cell structure elements are to be arranged in relation to one another - for example which common surfaces, edges or corner points have adjacent cell structure elements.

In this case, it is preferred if the production data record is created before and during the additive manufacturing process of the foam body. In principle, the production data record can be generated completely before the beginning of the additive manufacturing process and then contains a definition of the areas to be cured of each layer of the layered manufacturing process by grid point definitions in the respective layer. However, the production data set generated in this way is very large and therefore requires both a long creation time and a large amount of storage space. Alternatively, only a part of the or a first production data set can be generated before the start of the additive manufacturing process, for example the (part of) the production data set required for the production of the first three layers. During the production of the first three layers 1-3, a further part of or a second production data record can then be generated, for example the (part of) production data record required for layers 4-6. In this way, the required parts of the production data set or production data sets that build on one another can be produced continuously with a sufficient lead time during the ongoing additive production. In this way, computing time for the creation can be saved and, if parts of the production data record that have already been executed are deleted, storage space can also be saved.

A further aspect of the invention is a method for producing a foam body in an additive manufacturing process, with the steps: (i) creating a production data set of a foam body for an additive manufacturing process, in particular according to the method explained above, and (ii) producing the foam body in one additive manufacturing process based on the manufacturing data set.

It is preferred if the method is constructed with the following steps: producing the foam body from a large number of cell structure elements connected to one another, each cell structure element being constructed as a beam extending from a first node to a second node, and the construction of a cell structure element by action a focused beam of energy such as a laser along a single line onto a material from which the foam body is constructed, he follows. According to this development, the foam according to the invention is produced by the action of an energy beam, ie for example by melting a material previously applied, for example as a homogeneous powder layer, or by the action of radiation on a liquid, photopolymerizable material. The beam is not steered in the conventional manner by traversing the outer contour of the cell structure element once or several times with the energy beam for the purpose of curing the contour and then scanning the inner area of the contour for the purpose of curing the inner area. Instead, the invention makes use of the fact that the foam body is made up of long, thin cell structure elements and the surface quality of these cell structure elements does not have to be designed in a special way, since they are not important for the function and appearance of the foam body. In this way, the foam can be produced much more quickly while accepting acceptable losses in the surface quality of the cell structure elements.

The cell structure elements are therefore hardened along a single line by the action of the laser. The bundled energy beam can act continuously along the line or act on the material point by point, for example by pulsing the energy beam if the single line lies in a single layer plane of the additive manufacturing process. However, if the cell structure element extends obliquely to the planes of the layers and is accordingly formed by hardening of material areas in more than one layer, the only line along which the laser beam acts also runs obliquely to the layer planes and the action of the laser runs along this single one Line is made line section by line layer by layer.

The energy beam is preferably guided along the central longitudinal axis of a cell structure element, in particular by the focal point of an optionally bundled energy beam being focused on the central longitudinal axis of the cell structure element and being moved along this central longitudinal axis. A desired thickness of the cell structure element can then be generated by appropriate selection of the focal point size, energy and exposure time of the energy beam. In particular, the energy or exposure time and the focus point size of the energy beam can be set so high that the cell structure element in the corresponding layer is completely cured over its entire cross section through a point effect of the energy beam, in order to quickly and efficiently build up a cell structure element with a desired thickness. A further aspect of the invention is the use of a foam body of the type described above or a foam body produced using the production method described above as a seat cushion or backrest cushion of a seat, in particular a vehicle seat, orthopedic seat cushion. The production method according to the invention and the foam body according to the invention are particularly well suited for this type of application, because in such applications different properties in locally different areas are advantageous in order to achieve pleasant usage behavior for the user of the seat.

Finally, a further aspect of the invention is a computer program product comprising data which, when executed on a control computer of an additive manufacturing device, controls the production of a foam body on the additive manufacturing device. The computer program product according to the invention represents a data record that is suitable for controlling the manufacture of an additive manufacturing device. On the one hand, this can be the production data that is already suitable for direct control of the production facility, and on the other hand, it can also be the planning data from a digital planning process of such planning software, which usually has to be combined in such a way in order to generate production data for an additive production facility. The computer program product is characterized in that the data describe cell structure elements that correspond to the previously described cell structure elements of the foam according to the invention and, consequently, if they are executed on a computer that controls an additive manufacturing device, optionally after appropriate compilation, on the additive manufacturing device produce such foam.

Preferred embodiments of the invention are explained with reference to the accompanying figures. Show in it:

1 shows a schematic sequence of a production process for the foam body according to one embodiment of the invention,

2a-j ten possible variants of foam cells of a foam body according to the invention,

Fig. 3a-r eighteen possible variants ... geometry of a foam cell of a foam body according to the invention, 4a, b two views of a preferred geometry of a foam cell for a foam body according to the invention,

5a shows a view of the cell structure elements of a foam cell according to FIGS. 4a, b with geometry parameters entered,

5b shows a perspective view of the cell structure elements of the foam cell according to FIGS. 4a, b,

6a, b, c a numerical simulation of the deformation of a foam cell under vertical load in top view, side view and perspective view in an FEM modeling with representation of the component displacement,

7 Representation of test models for determining the foam properties

8 shows a force-displacement diagram with force-displacement curves entered therein for a conventional foam cube and a foam body with foam cells according to FIGS. 5a, b,

9 shows a force-displacement diagram of foam bodies according to with three different strut thicknesses.

Referring initially to FIG. 1, a foam body is produced according to the method according to the invention in several successive steps: in step A, the outer and inner geometry of the foam body is defined in a constructive planning process. Here, the desired outer dimensions of the foam body are determined, as is also necessary for each production of a product in a primary forming or machining manufacturing process. This can be done in a CAD process, for example. The results of this planning are, on the one hand, outer boundary surfaces, corner points and boundary edges of the foam body to be produced. In addition, areas within the foam body can be defined in this planning process, which should be designed with specific mechanical properties of the foam. The planning process according to step A also includes the selection of a suitable foam cell type for the foam body or several different suitable foam cell types for the foam body, provided that it has different areas in which different properties of the foam are provided. In this planning process, a foam cell geometry is selected, for example a truncated octahedron, whose dimensions are geometrically precisely defined with regard to the size of the foam cell and the geometric dimensions of the cell structure elements which form this foam cell. This can be done, for example, by selecting the corners of such a foam cell and the struts connecting these corners and the thickness of these struts. In the case of other foam cell geometries, wall profiles, wall thicknesses and the like can also be predetermined in this planning section.

Based on this geometric planning of the foam body, the complete geometric description of the foam body then takes place in a subsequent step B from the planning data after step A using geometric data. These geometric data describe all material volume contents of the foam body, ie all volume fractions on which additive material is to be placed and cured during the manufacturing process in order to build up the foam body. This planning step can often be carried out in partially or fully automated calculation processes, since matching foam cell geometries are also planned for the entire foam body or at least for areas with matching mechanical parameters and therefore these areas can also be planned digitally automated in the planning process with correspondingly matching foam cells. The result of this planning step B is a data set in which the outer and inner geometry of the foam body is fully defined. This data record can either be used directly as a production data record for controlling an additive manufacturing device or is also transformed for this purpose, for example compiled, in order to generate the necessary control commands for the additive manufacturing device from it. Manufacturing step B often also includes certain manufacturing strategies that are specific to the additive manufacturing process used. For example, auxiliary support elements, which support the distortion-free production of the foam body in the additive manufacturing process, can be planned, or an alignment, support of the foam body on a construction platform can be planned, which ensures high production precision and resolution as well as easy detachment. solution of the foam body from the construction platform. Furthermore, production parameters that define an exposure strategy can flow into the production data in this planning step.

The manufacturing data from step B are subsequently transmitted to an additive manufacturing facility. This may be, for example, a 3D printing device, a stereolithography device, an SLS/SLM manufacturing facility, or other additive manufacturing/rapid prototyping device, as discussed above. Using the manufacturing data from step B, the foam body is then built up step by step in step C in this additive manufacturing device. This can be done by adding layers or points and curing of material portions in the planned volume portions of the foam body.

In this additive manufacturing process, all of the foam cells and all of the possibly different areas of the foam body are designed and manufactured in a coherent manufacturing process.

In a subsequent post-processing step D, the foam body produced is removed from the additive manufacturing device after it has been completed there. If necessary, this includes detachment from the construction platform, separation of auxiliary structures and post-exposure for complete curing and production of the desired mechanical properties. Further post-treatment steps can also be carried out in this post-treatment step D by blasting with abrasive blasting material, grinding off external unevenness or the like to produce very specific desired properties. The result is a foam body that is finished in its external dimensions and has mechanical properties that are produced in a targeted manner in possibly different areas of the foam body, which can be used directly as a foam body for a product.

2 shows ten variants of possible foam cell geometries. These foam cells are made up of cell structure elements that are designed as struts, beams and walls. In the case of variants c and e, it should be understood that they differ on the one hand with regard to the cavity, which is designed with an oval cross section in variant c and with circular cross sections in variant e, and on the other hand with regard to the geometric dimensions, it being noted that in Variant e could also be used as a foam cell, a section of the cube shown there, which only has one of the twelve cavities shown. With regard to variants a, b, d, fj, it should be noted that the foam cells shown there can be designed with or without the upper and lower plate structure shown. This plate structure can be a cell structure element of the corresponding foam cell, but it can also be omitted, as a result of which the remaining cell structure elements of the foam cell can form the foam body as directly connected cell structure elements of adjacent foam cells.

With the exception of type b and i, the foam cell types shown in FIG. 2 have anisotropic mechanical properties, ie they behave mechanically differently from one another in different spatial directions. This can be used specifically to produce a foam body that also has such anisotropic, directional properties.

In contrast, FIG. 3 shows types of foam cells which exhibit isotropic behavior and can accordingly be used to construct a foam body with isotropic material properties. The foam cells shown are: a) tetrahedron, b) cube (hexahedron), c) octahedron, d) dodecahedron, e) icosahedron, f) truncated tetrahedron, g) truncated hexahedron, h) truncated octahedron i) truncated dodecahedron , j) truncated icosahedron k) cuboctahedron, I) rhombicuboctahedron, m) truncated cuboctahedron, n) truncated hexahedron, o) icosidodecahedron, p) rhombicicoisidodecahedron, q) truncated icosidodecahedron, r) truncated dodecahedron. In principle, it should be understood that a foam body can be produced from foam cells with these geometries.

Figure 4a, b shows a truncated octahedron which, according to the inventors, is a foam cell constructed based on such a truncated octahedron due to the relatively simple geometry and a good opportunity to parameterize such a foam cell geometry in a CAD model , suitable. Figure 4b shows the cell structure elements in the form of struts 1, 2, which run along the edges of this truncated octahedron, with nodes 3 shown as spheres.

Cell structure elements 10 of such a foam cell 50 are shown in FIGS. 5a, b and labeled with regard to the most important geometric parameters. In this case

H represents the maximum height, length and width of the foam cell, due to the isotropy of the foam cell shown here these three dimensions are the same. D represents the diameter of the struts that run along the edges of the foam cell and which are the cellular structural elements of the foam cell.

B represents the distance between the corner points of the inner square of the truncated octahedron, this geometry parameter is determined by the clipping height at which the octahedron was clipped to the truncated.

It can be seen in FIGS. 5a, b that the cell structure elements are halved at the contact areas 30a-e to adjacent foam cells in the direction of extension of the cell structure elements, that is to say they are designed with half the wall thickness. This results in a halved cross-section of the cell structure elements, which are thus formed here in a semi-circular cross-section.

In these contact areas, two adjacent foam cells will abut one another directly in the later foam body, so that the cell structure elements of the adjacent foam cell that are joined together there and are again halved in cross-section then produce a strut that is complete in cross-section, i.e. circular in cross-section here. In this way, the foam cell shown in FIGS. 5a, b can be used as an elementary cell, which can be duplicated as desired and lined up next to and on top of one another in order to build up a foam body with corresponding foam cells.

It should be understood that this principle can be retained if the cross-sectional geometry of the cell structure elements differs, for example, with a square cross-sectional geometry of the cell structure elements, a rectangular cross-sectional geometry in the interfaces to adjacent foam cells with half the side length of the rectangle compared to the square edge length or a triangular cross-sectional geometry of the struts can be provided , in order to define a unit cell that is suitable for stringing together any number of foam cells.

A foam cell of the structure shown in Fig. 5a,b can be designed, for example, with a height, length and width in the range between 2 and 10 mm, preferably in the range between 3 and 7 mm, particularly preferably in the range of 5 mm+ // 0.5mm. The thickness of the struts can be varied between 0.5 and 2 mm, preferably in the range from 0.7 to 1.2 mm, with a strut thickness of 1 mm +/- 0.1 mm being particularly preferred. With these dimensions, a foam cell can be created from which a foam body can be produced that, for typical foam body applications, generates a homogeneous mechanical behavior that is uniform over the surface in relation to the loads that occur.

6 shows, in a top view (a), a side view (b) and a perspective view (c), the deformation of such a foam cell when loaded in the vertical direction. It can be seen that the foam cell can be deformed elastically or, depending on the choice of material, viscoelastically with partial bending, elongation and compression of the struts. The material stresses occurring here are distributed essentially evenly over the material volume, as a result of which stress peaks, which would lead to the failure of the cell structure elements, are avoided.

FIG. 7 shows six foam bodies that are made up of foam cells that are geometrically identical, but differ from one another in the thickness of the struts. From right to left, the foam bodies have a strut thickness of 0.7 mm, 0.9 mm, 1 mm, 1.1 mm, 1.3 mm and 1.5 mm.

Fig. 8 shows the force (y-axis) - extension behavior (x-axis) of a foam body from the foam cell according to FIG. 5a with a foam cell having a length, width and height of 5 mm and a strut thickness of 0.7 mm is achieved (upper curve) and in comparison to this the force-strain behavior of a conventionally produced foam body (lower curve). For this purpose, a foam body was produced which has a square outer geometry and consists of a total of 125 foam cells of this type with an edge length of 25 mm, as shown on the left in FIG.

As can be seen from the can be with a foam body of the type according to the invention, which was produced with the method according to the invention, a force-displacement behavior - th achieved that a conventional foam cube with a compressive strength of more than 2kPa, more than 3kPa and preferably more than 5kPa and a compression hardness of less than 20kPa, less than 15kPa and preferably less than 13kPa according to DIN EN ISO 3386-1.

9 shows the force-strain curve for foam bodies made from foam cells with three different strut thicknesses. The six lowest curves for a foam body with a strut thickness of 0.8 mm were recorded and show on the one hand the good reproducibility of the mechanical properties in the inventive manufacturing process, on the other hand, the high degree of deformation that can be achieved with this small strut thickness with low force. This foam body has a compressive strength of 3.3 kPa according to DIN EN ISO 3386-1.

The six curves in the middle show the force-strain behavior of a foam body with a strut thickness of 0.9 mm with otherwise the same foam cell geometry as in the lower curve. It can be seen that by increasing the thickness of the struts by 0.1 mm, the deformation is roughly halved, or that twice as much force is required on the foam body for the same deformation. This foam body has a compressive strength of 5.2 kPa according to DIN EN ISO 3386-1.

The six upper force-strain curves were recorded on a foam body with the same foam cell geometry and a strut thickness of 1 mm. It can be seen that the hardness of the foam is twice as high as that of the middle curve, i.e. for the same degree of deformation, a force that is about twice as high as that of the middle curve has to be applied and that of the lower curve with a strut thickness of 0.8, a force that is about four times higher . This foam body has a compressive strength of 9.2 kPa according to DIN EN ISO 3386-1.

The foam bodies according to the invention can be produced from different materials. In principle, for example, polyurethanes or thermoplastic elastomers based on urethane are suitable for this purpose. Such TPU materials are available, for example, for the additive manufacturing process in the powder bed process (SLS) under the trade name LUVOSINT X92A-1 in two different Shore A hardnesses (identifier A-2 for 92ShoreA; identifier WT for 97ShoreA. These materials are suitable for a Mechanical recycling, since they are thermoplastic and can therefore be fully recycled in an environmentally friendly manner at the end of their useful life.

The areas of application of the foam body according to the invention range from upholstery material for the furniture and automotive industry, in particular for upholstered furniture, car seats or mattress foam, to cleaning sponges, filter material, insulating material.

In principle, it should be understood that the foam body according to the invention can be made up solely of foam cells, as has been described above. Because of the free Plannability of the inner and outer geometry of such a foam body can, however, also be integrated through the foam body or in this foam body partly or completely inserted additional components by these as the foam cells penetrating or structures running past these foam cells are taken into account in the planning process. These additional components are then directly taken into account in the manufacturing data of the foam body and can consequently be manufactured simultaneously with the foam cells of the foam body in additive manufacturing processes in one manufacturing step.

For example, tubular lines, which can be used as cable ducts, air ducts or fluid ducts, come into consideration as such structures. In this way, ventilated, cooled, heated seat cushions can be implemented or electrical lines can be routed through such seat cushions that have been produced as a foam body according to the invention. In addition, complex components can also be manufactured integrally within or partially within the foam body according to the invention in one operation with the foam cells using the additive manufacturing process. Various methods are known for producing mechanical elements from different materials in certain additive manufacturing processes, including electrical lines, circuits and electronic components produced in the process. In this way, components such as loudspeakers or lighting devices can consequently be integrated into the foam body according to the invention.

Claims

- 32 -

Claims Method for producing a three-dimensional foam body, wherein the

Foam body consists of an open-pore or closed-pore foam structure and correspondingly has cavities communicating with one another and/or with the environment or cavities closed off from one another and/or from the environment, characterized by the steps:

Production of a large number of foam cells by building up cell structure elements which at least partially enclose a cell cavity by means of an additive manufacturing process, and

Creating a connection between the cell structure elements of the foam cells using the additive manufacturing process. Method according to claim 1, characterized in that the foam body has a first foam body section with a first type of foam cells and a second foam body section with a second type of foam cells different from the first type. Method according to Claim 2, characterized in that only foam cells of the first type are arranged in the first foam body section and/or in that only foam cells of the second type are arranged in the second foam body section. The method according to claim 2 or 3, characterized in that the first and the second type of foam cells is formed by cell structure elements whose arrangement and course is the same and that the wall thickness of a cell structure element in an arrangement and a course in relation to a foam cell of the first type is different - 33 - of the wall thickness of a cell structural element in the same arrangement and course in relation to a foam cell of the second type. Method according to one of the preceding claims, characterized in that the additive manufacturing method is selected from: a 3D printing method, a stereolithography method, a selective laser sintering/laser melting method

binder jetting,

fused deposition modelling,

polyjet process,

Digital Light Processing, HP Multijet Fusing. Method according to one of the preceding claims, characterized in that the cell structure elements are made of a material selected from: an elastomeric material, a thermoplastic elastomeric material, a polyurethane, in particular thermoplastic polyurethane, a polyvinyl chloride, a polymer with a Shore A hardness of at least 50, 60, 70 or 80 and not exceeding 90 or 100. Method according to one of the preceding claims, characterized in that the geometry of the cell structure elements of the foam body is defined by digital planning data before the additive manufacturing of the cell structure elements and a manufacturing data record is created from the digital planning data, with which the additive manufacturing process is controlled. 8.) Method according to one of the preceding claims, characterized in that at least two foam cells, preferably more than twenty foam cells and in particular more than one hundred foam cells are geometrically identical.

9.) Method according to one of the preceding claims, characterized in that the foam body comprises foam cells or consists of foam cells which have the geometry of an Archimedean body.

10.) Method according to claim 9, characterized in that the foam cells are selected from:

Polyhedron truncated polyhedron, an Archimedean solid that has plane-parallel surfaces in all three spatial directions, a truncated octahedron, a cubotahedron.

11 .) Method according to one of the preceding claims, characterized in that the foam body comprises foam cells or consists of foam cells, which are delimited by planar geometric surfaces that adjoin one another at surface edges and that the cell structure elements of a foam cell are arranged as bars along some or all edges of the extend foam cell.

12.) Method according to one of the preceding claims, characterized in that a foam cell comprises an upper cell structure element surface, a lower cell structure element surface and lateral cell structure element surfaces, and that the upper cell structure element surface of a cell is integral with the lower cell structure element surface of an overlying adjacent foam cell, the lower cell structure element surface of a cell is integral with the upper cell structure element surface of an underlying adjacent foam cell, and/or a lateral cell structure element surface of a cell is integral with a lateral cell structure element surface of a laterally adjacent foam cell .

13.) Foam body, comprising a multiplicity of foam cells, which are formed by a cavity surrounded by cell structure elements, characterized in that the cell structure elements are produced in an additive manufacturing process.

14.) Foam body according to claim 13, characterized in that the cell structure elements have a size that fits into a spherical body with a diameter of less than 2, 4, 6, 8 or 10 mm, preferably less than 5 mm.

15.) Foam body according to claim 13 or 14, characterized by a first section comprising or consisting of foam cells of a first type and a second section comprising or consisting of foam cells of a second type different from the first.

16.) Foam body according to one of claims 13 to 15, characterized in that the cell structure elements consist of an elastomeric material.

17.) Foam body according to one of the preceding claims 13-16, characterized in that one or more functional components are arranged in the foam body or on the outer surface of the foam body, which are preferably produced in the same additive manufacturing process as the foam, and in particular are selected from : - 36 - a) attachment sections for attaching the foam body to another component or for attaching other components such as sensors to the foam body, b) integrated channels, in particular for ventilation or for a cold or heat fluid, c) a closed or apertured outer surface layer of the Foam body, in particular a seat layer, the mechanical properties of which differ from the properties of the interior of the foam body, d) damping elements that have an energy-absorbing behavior due to internal friction or friction of two structural elements together, in particular for shoes / shoe soles e) integrated loudspeakers, including cables for their energy supply f) integrated light sources, including lines for their energy supply Use of a foam body according to one of Claims 13-17 or of a foam body produced by a method according to Claims 1-12 as a seat cushion or Backrest cushion for a seat, in particular a vehicle seat. Method for generating the production data record for the production of a

foam body in an additive manufacturing process, with the steps:

Defining the outer boundary surfaces of the foam body in a vector-based digital planning program and creating a first planning data set from the specified outer boundary surfaces,

Defining the geometry of a cell structure element in the vector-based digital planning program and creating a second planning data record from the geometry of the cell structure element,

Creation of a manufacturing data set, which includes manufacturing data for an additive manufacturing process of the foam body, from the first and second planning data set by the first planning data set - 37 - defined volume, which is enclosed by the outer boundary surfaces, is filled with a large number of lined-up cell structure elements, each of which has a geometry according to the second planning data set.

20.) Method according to claim 19, with the steps: characterized in that the production data set is created before and during the additive manufacturing process of the foam body.

21 .) Method for producing a foam body in an additive manufacturing method, with the steps:

Generating a production data set of a foam body for an additive manufacturing process, in particular according to the method according to claim 19,

Manufacture of the foam body in an additive manufacturing process based on the manufacturing data set.

22.) Method according to claim 21, with the steps:

Manufacture of the foam body from a plurality of interconnected cellular structural elements, each cellular structural element being constructed as a beam extending from a first node to a second node, and constructing a cellular structural element by exposure of a focused beam of energy, such as a laser, along a single line to a Starting material from which the foam body is constructed takes place.

23.) Method according to claim 22, characterized in that the bundled energy beam acts point by point along the line on the material. - 38 - Computer program product, comprising data which, when executed on a control computer of an additive manufacturing device, control the production of a foam body on the additive manufacturing device, in particular the production of a foam body by a method according to one of claims 1-12 or the Production of a foam body according to any one of claims 13-17.