Additive manufacturing method for metallic heating disks for an exhaust gas aftertreatment system and metallic heating disks

Abstract

An additive manufacturing method for at least one metallic heating disk for an exhaust aftertreatment system, comprising: additively generating at least one heating disk comprising: a plurality of cells comprising a honeycomb cell structure; parallel discontinuous slots; and locally varying cell densities.

Description

[0001] Additive manufacturing method for metallic heating disks for an exhaust gas aftertreatment system and metallic heating disks

[0002] Field of the invention

[0003] The present invention relates to metallic heating disks for exhaust gas aftertreatment systems, in particular to additive manufacturing methods therefor and products manufactured accordingly.

[0004] Background to the invention

[0005] Known exhaust gas aftertreatment systems work with heating devices that are used specifically to support cleaning processes of engine exhaust gases before they are released into the ambient air. In order to be able to meet future emission targets and regulations (e.g. LEV 4, Euro 7, Stage 6, Tier V), continuously improved active thermal management technologies are required in connection with exhaust gas aftertreatment systems for combustion engines, particularly with the aim to reduce cold start emissions and to keep exhaust system components warm.

[0006] In this context, some systems use heating elements to bring the exhaust gas in the exhaust tract to an optimum operating temperature for a downstream diesel particulate filter (DPF) or for catalytic converters, such as diesel oxidation catalytic converters (DOC), SCR catalytic converters, three-way catalytic converters (TWC) and gasoline particulate filters (GPF), to remove hydrocarbons (HC), carbon monoxide (CO) or nitrogen oxides (NOx). A specific heating of the exhaust gas is particularly required after a cold start of the engine, but also in all cases in which the exhaust gas temperature drops because either the operating temperature of the engine decreases or because a long conveying path of the exhaust gas between engine and DPF due to the installation space causes the gas to cool down. Well-known designs of such heating elements include electric heating disks made of ceramic or metallic materials, which are usually complex and costintensive to manufacture.

[0007] In this context, US 2022 1 0 061 130 A1 teaches the manufacture of spiral heating disks by means of additive manufacturing. A disadvantage of the manufacturing method presented here, however, is that the manufacture of individual heating disks using this method is particularly time-consuming and cost-intensive due to the respective machine set-up times that have to be carried out for each individual sintering method. In addition, any series production of the heating disks proposed here would take a relatively long time, which is why it is currently not worthwhile. In particular, in

[0008] US 2022 10 061 130 A1 the housing of the heating disk is also printed, which is significantly more expensive compared to the usual production from sheet metal parts.

[0009] The present invention relates to the additive manufacturing of metallic heating disks, which preferably comprise a fine-mesh honeycomb structure with a meandering design. The additive manufacturing method used for this purpose is a powder bed-based melting method, preferably laser sintering, laser beam melting, electron beam melting, binder jetting and / or thermal transfer sintering, in each case using thermal energy to selectively join or fuse regions of a powder bed. In the aforementioned 3D printing methods, powder material is melted in layers, for example with a laser, to create a desired three-dimensional geometry. Unused powder around the created geometry, and in particular in the gaps created, must then be removed. A particular challenge therefore lies in what is known as depowdering. Depowdering refers to the removal of residual, unused powder material from an additively manufactured structure. Complete removal of powder residues from such a fine structure as a fine-meshed heating disk is difficult, but necessary to ensure its functionality.

[0010] Another challenge in connection with the production of electric heating discs is to ensure a time- and cost-efficient manufacturing method. It is therefore preferable to produce several heating discs in one and the same manufacturing method, namely in the form of a stack that is several times thicker than a single finished heating disc. In the present case, it is therefore first necessary to produce a corresponding stack using the additive manufacturing methods mentioned herein and, after completion of the underlying melting method, to separate it into individual discs with an exact, uniform and repeatable thickness. However, known separation methods, such as cutting or sawing, which is required here over the entire cross-section of the slice, take a disproportionately long time and are therefore correspondingly expensive. of the invention

[0011] The object of the present invention is therefore to overcome the disadvantages described above as well as other disadvantages associated with the prior art. of the invention

[0012] The above object and further problems are solved by metallic heating disks for an exhaust gas aftertreatment system and by corresponding additive manufacturing methods therefor according to the independent claims. The dependent claims relate to preferred embodiments of the invention.

[0013] An additive manufacturing method according to the invention for at least one metallic heating disk for an exhaust gas aftertreatment system comprises the following: additively producing a support structure on a base and additively producing at least one heating disk on the support structure. Flow openings are formed between the base and the heating disk by means of the support structure. In addition, together with internal openings of the at least one heating disk, the flow openings form a plurality of channels. The internal openings correspond to the specific structure of a respective heating disk, more precisely its honeycombs.

[0014] The support structure generated by the additive manufacturing method can comprise 20 to 70 %, preferably 35 to 55 %, particularly preferably 40 to 50 % of the material that is used for the corresponding height portion when producing a heating disk. Especially in a transition region between the structure of the at least one heating disk and the support structure, a changing cross-section can thus occur, for example due to correspondingly inclined and / or conical portions.

[0015] The additive manufacturing method is optionally a powder bed based melting method, wherein the method further preferably comprises a step of removing remaining powder particles, and wherein the removing is particularly preferably a vibrating, shaking out, sucking out and / or blowing out of remaining powder particles along the plurality of channels.

[0016] Furthermore, at least one heating disk produced by means of the additive manufacturing method according to the invention can be a stack of heating disks, wherein the method preferably comprises a step of separating the stack of heating disks produced into individual heating disks, and wherein the step of separating is particularly preferably carried out by means of spark erosion or by means of wire erosion.

[0017] Optionally, the additive manufacturing method can also involve grinding and / or milling off the support structure and / or the surfaces of the heating disks separated from one another and / or removing the support structure by means of spark or wire erosion.

[0018] An alternative additive manufacturing method according to the invention for metallic heating disks for exhaust gas aftertreatment systems comprises additively generating, creating or producing a stack of heating disks each comprising a spacer structure between the individual heating disks in the stack of heating disks. The spacer structure comprises a height and the material used to create each spacer structure in the height corresponds to 20 to 70 % of the material used for a corresponding height portion when generating, creating or producing a heating disk. Particularly in a transition region between the structure of the at least one heating disk and the support structure, a changing cross-section can thus occur, for example due to correspondingly inclined and / or conical portions. The additive manufacturing method can also include a step of separating the generated stack of heating disks into individual heating disks at the level of the spacer structure. The separation can thus take place in the respective area of the spacer structure, preferably by means of spark erosion, particularly preferably by means of wire erosion. The parameters required for a corresponding separation method, such as current intensity, cutting thickness and / or cutting speed, are set individually for the workpiece in question. The use of molybdenum wire is preferred in connection with wire erosion, although other wire materials are also possible depending on the workpiece and material. The separation of a stack can optionally be carried out in individual separating steps, i.e. heating disks are separated parallel to the base and in an opposite melting direction. Furthermore, the separation is preferably carried out individually. Optionally, the separation can preferably take place at right angles to the stack or the base. Alternatively, it is optionally possible to separate two or more heating disks at the same time or to carry out all separation steps simultaneously according to the total number of additively produced heating disks. Hybrid production systems are also optionally provided, in which separation can also take place directly after additive manufacturing.

[0019] The spacer structure produced by means of the alternative additive manufacturing method according to the invention can furthermore be formed by a plurality of parallel ribs. The plurality of ribs can correspond to the honeycomb structure of a heating disk located above and / or below. The ribs can, for example, be produced by a simple scanning or sampling of the powder bed using a laser, whereas the honeycombs of the cell structure of the heating disks are produced by double scanning or sampling using the laser.

[0020] Furthermore, the height of each spacer structure can optionally lie between 0.2 to 3 mm, preferably 0.2 to 1 mm, particularly preferably 0.2 to 0.4 mm.

[0021] A wire used in wire EDM can optionally comprise a diameter of between 0.1 and 0.4 mm, preferably between 0.18 and 0.3 mm. An exemplarily used molybdenum wire may comprise a diameter of 0.18 mm, although specific wire thicknesses of other materials are also possible that lie in the aforementioned ranges, such as 0.2 or 0.25 mm. In wire EDM in particular, it is assumed that approximately 0.1 mm more is cut off than the thickness of the wire used. This relationship may need to be taken into account when designing the spacer structure.

[0022] The material used to generate each spacer structure may further correspond to 35 to 55%, preferably 40 to 50%, of the material used for a corresponding height portion when creating a heating disk

[0023] The step of generating the stack of heating disks may further optionally comprise additively generating, creating or producing a support structure between a base, to form flow openings between the support structure and the base, and the lowermost heating disk of the stack of heating disks. The flow openings can form a plurality of channels with internal openings of the stack of heating disks.

[0024] In addition, the spacer structures between the individual heating disks can differ from the support structure. For example, in contrast to the support structure, the spacer structure may comprise no radial opening and / or flow channels. At the same time or alternatively, either the support structure or the spacer structure can each comprise only a part of the walls compared to the actual disk. Simultaneously or alternatively, both the support structure and the spacer structure may each comprise a different part of the walls compared to an actual heating disk. Simultaneously or alternatively, the thickness of the respective walls can be reduced in only one of the two structures. Simultaneously or alternatively, the thickness of the respective walls can be reduced differently in both structures compared to an actual heating disk.

[0025] Optionally, the alternative additive manufacturing method may further comprise a step of grinding and / or milling off residues of the spacer structure that remain after separation. An additional alternative additive manufacturing method according to the invention for at least one metallic heating disk for an exhaust gas aftertreatment system comprises additively producing at least one heating disk comprising: a plurality of cells comprising a honeycomb cell structure; parallel non-continuous slots; and locally different cell densities.

[0026] The locally different cell density can optionally comprise locally increased cell densities on the heating disk, preferably at current turning points in the area of slot ends located inside the heating disk, whereby locally increased cell densities at the slot ends are particularly preferably present at most in the range of 1 / 10 to 1 / 4 of the total slot length of a shortest slot.

[0027] Furthermore, the locally different cell density of the heating disk can optionally be defined by at least one of the following parameters: locally reduced cell size of individual or several cells; locally changed cell shape of individual or several cells; local combination of different changed cell shapes; and increased wall thicknesses of individual cells.

[0028] The locally different cell density of the heating disk can also optionally comprise that the number of cell walls is locally increased by a factor of 1.5 to 3.5 compared to the remaining cell walls. Preferably, the average cell density is 62 to 124 cells / cm2(400 to 800 cells per square inch, CPSI). Such an optional cell density is particularly suitable in the region of current turning points, as a specifically defined current flow can be desirable in order to increase the service life of a heating disk.

[0029] The at least one heating disk produced by means of the additional alternative additive manufacturing method can optionally be a stack of heating disks.

[0030] Furthermore, the additional alternative additive manufacturing method can also comprise a step of separating the stack of heating disks produced into individual heating disks, the step of separating preferably being carried out by means of spark erosion, particularly preferably by means of wire erosion.

[0031] The material of the at least one heating disk used for all additive manufacturing methods according to the invention can optionally comprise a permanent temperature resistance of 850 to 1000 °C, preferably 900 to 950°.

[0032] The material of the at least one heating disk used for all additive manufacturing methods according to the invention can optionally be a Ni-based material, an iron-chromium-aluminum material (e.g. FeCrAI 1.4767), an austenitic steel material or a ferritic steel material.

[0033] The additive production of the at least one heating disk or the stack of heating disks as part of all additive manufacturing methods according to the invention can optionally include the additive production of two additional electrode arms in the same production step

[0034] All additive manufacturing methods according to the invention can optionally provide for production of the at least one metallic heating disk in a horizontal position (lying) relative to the base.

[0035] All additive manufacturing methods according to the invention can optionally be powder bed-based melting, preferably laser sintering, laser beam melting, electron beam melting, binder jetting and / or thermal transfer sintering. For any combinations of the aforementioned manufacturing methods, parameters such as dimensional accuracy and / or material density must be taken into account. Powder to be melted can optionally comprise particle sizes with diameters in the range of 10 to 60 pm. Exemplary layer thicknesses of powder particles to be melted may lie approximately in a range of 100 to 150 pm, preferably around 60 to 120 pm. An exemplary 3D print of a stack of 5 heating disks with a total height of about 27 mm using a laser takes about 11 .5 hours. Alternatively, several stacks of the same height can be produced in parallel in the same time, in each case using one laser per stack, depending on the available base area and / or the installation space of the 3D printer used. The aforementioned printing time can also optionally be reduced by using several lasers per stack at the same time.

[0036] All additive manufacturing methods according to the invention may optionally further comprise the following step: removing remaining powder particles, preferably by means of vibrating, shaking out, sucking out and / or blowing out, particularly preferably from one or two sides.

[0037] The at least one heating disk or the stack of heating disks according to any additive manufacturing method according to the invention may optionally comprise a honeycomb cell structure and / or cells having a triangular, square or quadratic, rectangular, pentagonal, hexagonal, polygonal structure or any combination thereof. One promising option is a heating disc preferably comprising such cell structure and being made of a high temperature resistant material (e.g., Ni-Cr- or Fe-Cr-AI-alloy), which shows a very good heating performance in combination with only small package space requirements.

[0038] Optionally, the at least one heating disk or the stack of heating disks produced by any additive manufacturing method according to the invention may combine rectangular cells with square or quadratic cells, preferably using a combination of only rectangular cells and square or quadratic cells. In this context, preferably all regions having a lower power density (low current flow) or inactive areas (no current flow) may have a rectangular cell shape or cell structure. The high power density regions, such as current turning points or current flow turning points, may then have a quadratic cell shape or cell structure. The advantage of such a design composition is to reduce the piece price of heating disks significantly with no or close to no negative impact on their performance. An optional length to width ratio of rectangular cells may be 2:1 .

[0039] The heating disks according to any additive manufacturing method according to the invention can optionally comprise a honeycomb cell structure comprising a meandering structure, which is preferably formed by parallel non-continuous slots, the slots extending particularly preferably alternately from the outer circumference of the heating disk starting into the interior of the disk.

[0040] The heating disks according to any additive manufacturing method according to the invention may optionally comprise a diameter of 200 to 250 mm, preferably 200 to 220 mm, with an average cell density of 8 to 31 cells / cm2(50 to 200 cells per square inch), preferably 14 to 18 cells / cm2(90 to 180 cells per square inch).

[0041] Alternatively, the heating disks according to any additive manufacturing method according to the invention may optionally comprise a diameter of 150 to 200 mm, preferably 150 to 180 mm, with an average cell density of 8 to 46 cells / cm2(50 to 300 cells per square inch), preferably 8 to 15 cells / cm2(50 to 200 cells per square inch).

[0042] Alternatively, the heating disks according to any additive manufacturing method according to the invention may optionally comprise a diameter of 100 to 150 mm, preferably 100 to 110 mm, with an average cell density of 11 to 60 cells / cm2(75 to 400 cells per square inch), preferably 15 to 38 cells / cm2(100 to 250 cells per square inch).

[0043] The heating disks according to any additive manufacturing method according to the invention can optionally have a height of 4 to 10 mm, preferably 4.5 to 7 mm, particularly preferably in relation to the diameter or the cross-sectional area of the heating disk. In principle, the larger the disk diameter or cross- sectional area, the greater the height of the heating disk. Individual cells can have edge lengths of around 1 or 1 .5 to around 3 mm or more. This can result in individual surfaces of around 1 to 9 mm2.

[0044] A heating disk according to the invention may be manufactured using the additive manufacturing method according to the invention, using the alternative additive manufacturing method according to the invention or using the additional alternative additive manufacturing method according to the invention. The heating disk can optionally comprise a nominal output of up to 15 kW with a diameter of up to 200 mm; or the heating disk can comprise a nominal output of up to 25 kW with a diameter of up to 300 mm.

[0045] Furthermore, a metallic heating disk for an exhaust gas aftertreatment system according to the invention, produced in a single manufacturing method, comprises: a plurality of cells comprising a honeycomb cell structure and locally different cell densities; parallel non-continuous slots; and two electrode arms.

[0046] The locally different cell density of the metallic heating disk can optionally comprise locally increased cell densities on the heating disk, preferably at current turning points in the area of slot ends located inside the heating disk, whereby locally increased cell densities at the slot ends are particularly preferably present at most in the range of 1 / 10 to 1 / 4 of the total slot length of a shortest slot.

[0047] The at least one heating disk may optionally further comprise rectangular cells in non-active areas and in low power and / or low current density areas; and quadratic or square cells in high power and / or high current density areas, preferably close to a current turning point; wherein rectangular cells preferably comprise a length to width ratio of 2:1 .

[0048] The at least one heating disk may optionally further comprise a grid of triangular cells, either alone or in combination with square and / or rectangular pattern; wherein preferably the grid of triangular cells comprises triangular cells of same or different sizes, preferably having smaller cells in the center and bigger cells on the edges or smaller cells on the edge and bigger cells in the center.

[0049] The locally different cell density of the metallic heating disk can optionally be such that the number of cell walls is locally increased by a factor of 1 .5 to 3.5 compared to the remaining cell walls, preferably with an average cell density of 62 to 124 cells / cm2(400 to 800 cells per square inch). Such an optional cell density is particularly suitable in the region of the current turning points, as a specifically defined current flow can be desirable here to increase the service life of a heating disk.

[0050] Brief description of the drawings

[0051] The invention as well as further details and advantages thereof are explained below with reference to the figures using preferred embodiments. The figures show:

[0052] Fig. 1 A a top view of a heating disk;

[0053] Fig. 1 B a further top view of the heating disk as shown in Fig. 1 A with schematic electrode connections;

[0054] Fig. 1 C a partial isometric side view of the heating disk according to Fig. 1A and Fig. 1 B;

[0055] Fig. 2 a stack of unseparated heating disks on a base with schematically indicated separation planes;

[0056] Fig. 3A a longitudinal cut through the stack as shown in Fig. 2;

[0057] Fig. 3B a partial view of Fig. 3A with schematic powder removal mechanism;

[0058] Fig. 4A a partial longitudinal sectional view through the stack according to Figs. 3A and 3B having a support structure according to the invention;

[0059] Fig. 4B a partial longitudinal sectional view through a lowermost heating disk of the stack according to the invention together with the support structure according to the invention as shown in Fig. 4A with marking of two cut planes 1-1 and 2-2;

[0060] Fig. 4C a cross-sectional view 1-1 of the heating disk as shown in Fig. 4B;

[0061] Fig. 4D a cross-sectional view 2-2 of the support structure as shown in Fig. 4B;

[0062] Fig. 5 a side view of two heating disks of the stack according to Fig. 2 and a spacer according to the invention located between them;

[0063] Fig. 6A and 6B cross-sectional views of exemplary spacers according to Fig. 5; Fig. 7A a heating disk according to the invention with locally varying cell density;

[0064] Fig. 7B an enlarged partial view of the heating disk as shown in Fig. 7A;

[0065] Fig. 7C a sectional view along A-A as indicated in Fig. 7B;

[0066] Fig. 8A-D in each case a part of a heating disk at a slot end with different versions of locally increased cell densities; and

[0067] Fig. 9 various configurations for flexible grid layouts of heating disks.

[0068] Detailed description of the invention

[0069] In the present description, the expressions top, bottom, right and left and similar indications refer to the orientations or arrangements shown in the figures and serve only to describe the embodiments. These expressions may show preferred arrangements, but are not to be understood in a restrictive sense.

[0070] Furthermore, the expressions "substantially", "approximately", "about" and similar expressions mean that deviations of + / -10%, preferably + / -5%, from the stated value are permissible.

[0071] Unless explicitly excluded, the value ranges mentioned above are always understood to mean that lower edge areas with ">", greater than or equal to, and upper edge areas with "<", less than or equal to, are considered to be included in the mentioned value range. In particular, the edge areas themselves are therefore either included in the respective range, but can alternatively also be (unilaterally) excluded.

[0072] Fig. 1A shows a top view of a heating disk 10 of an exhaust gas aftertreatment system. The heating disk 10 comprises a plurality of cells 12 and a plurality of slots 14. The slots 14 are parallel to each other as far as this is possible due to the manufacturing method. Furthermore, they each project alternately from an outer circumference of the heating disk 10 into its interior, although they do not extend over the entire disk surface. A current turning point 16 is located at each of the ends of the plurality of slots 14 located inside the disk. Fig. 1 B shows a further top view of the heating disk 10 according to Fig. 1 A with schematic electrode connections for a positive and a negative pole, which can be connected via two electrode arms (not shown). Fig. 1 C is a partial isometric side view of the heating disk 10 according to Fig. 1A and Fig. 1 B, which reflects a schematic relationship between a height h of the heating disk 10 and a diameter d of the heating disk 10. While the heating disk 10 is shown here as round, the present invention is equally applicable to heating disks of other formats, for example oval, elliptical or kidney-shaped. Due to the fine, thinwalled structure of the heating disk 10, it is preferably additively manufactured in the present case in a horizontal direction, i.e. in a flat orientation of the heating disk 10.

[0073] Fig. 2 shows a stack 20 of unseparated heating disks 10 on a base 22 with schematically indicated separating planes 24 between the individual heating disks 10 of the stack 20. The base 22 is part of a manufacturing device (not shown further), in particular an additive manufacturing device, on which a number of heating disks 10 were produced in a single manufacturing process by means of the method of the present invention in the form of the stack 20. Stack sizes of a stack 20 of 5 to 100 heating disks, preferably 30 to 100, particularly preferably 50 to 60 heating disks are conceivable. The number of heating disks 10 within a stack 20 can vary depending on the thickness or height h (see Fig. 1 C) of the individual heating disks and the installation space available in the production device. In addition, disks with a larger diameter d generally also comprise a greater thickness, preferably up to around 10 mm.

[0074] Fig. 3A shows a longitudinal cut through the stack 20 of unseparated heating discs 10 shown in Fig. 2. Vertical lines to the base 22 can be seen here in a sectional view. These lines schematically indicate walls of a honeycomb cell structure 26 (only partially indicated in the sectional view of Fig. 3A), for example, the plurality of cells 12 according to Figs. 1 A and 1 B, of each individual heating disk 10. Stacked on top of each other, this results in a plurality of channels 28 in three-dimensional space between the base 22 and an uppermost heating disk 10. As described at the beginning, the present invention relates to the additive manufacturing of metallic heating disks produced by means of powder bedbased melting. After completion of a melting process, in this case of the production of the stack 20 of heating disks 10, it is necessary to remove unused powder around the produced geometry and in particular from produced interstices, more precisely from the honeycomb cell structure 26 (depowdering). For this purpose, remaining powder particles are removed by vibrating, shaking out, sucking out and / or blowing out. In this context, Fig. 3B shows a partial view of Fig. 3A (upper right corner) with a schematic powder removal mechanism 30. The mechanism 30 shown here removes remaining particles 32, for example by means of suction, from the plurality of channels 28 of the stack 20. However, complete removal of all remaining particles 32 becomes more difficult the more complex the honeycomb cell structure 26 of the stacked heating disks 10 becomes. A suction applied by the mechanism 30 (indicated here by arrows pointing upwards) reaches the upper heating disks 10 of the stack 20 better than heating disks located further down. In addition, negative pressure can arise between the base 22 (see, for example, Fig. 3A) and the lowest heating disk 10 in a worst case, which may make it impossible to completely extract any remaining particles 32 already in the production device. Even after removal of the stack 20 produced and after a suitable positioning on a surface (for example perforated or provided with holes) for further depowdering, there are still problems at this point due to the negative pressure that builds up. Furthermore, if the mechanism 30 were able, for example, to remove the particles 32 by blowing them out (not shown), this would in the worst case either not reach some lower heating disks or even endanger the structure of heating disks further up. However, it would be disadvantageous in this respect to first separate the stack from the base, since further separation methods may result in problems when gripping and / or fixing and / or handling the stack (which is potentially getting smaller).

[0075] The depowdering via an exemplary subsequent suction method step can be improved if additional openings are provided between the printed structure and the base plate (base 22 of the printing machine). This enables suction from 2 sides or to allow compressed air to flow in from one side and suction from the other side, which significantly improves the cleaning result. In view of this problem, Fig. 4A shows a further partial longitudinal cut through the stack 20 as shown in Figs. 3A and 3B. In addition, there is a support structure 40 located between the base 22 and a lowermost heating disk 10 of the stack 20. In the additive manufacturing method, the support structure 40 is produced first and then the stack 20 is produced on top thereof. By means of the support structure 40, a plurality of flow openings 42 is formed between the base 22 and the lowermost heating disk 10. The flow openings 40 together with internal openings, more precisely the honeycomb cell structure 26, form channels 28 that have been modified in such a way that they are now largely open at the bottom. In Fig. 4A, four schematic arrows indicate that air can now flow through the flow openings of the support structure 40. This enables the mechanism 30 to depowder the stack 20 completely. Depending on the quantity and shape of the flow openings 42 in the support structure 40, potential extraction by suction (alone or in combination with other particle removal variants such as vibrating, shaking out, out and / or blowing out) is significantly improved. Remaining suction pressure or negative pressure, as described above, no longer counteracts this, or only does so without significant problems. The quantity and shape of the flow openings 42 in the support structure 40 can be defined by the material used there. Accordingly, the support structure 40 comprises approximately 20 to 70 %, preferably 35 to 55 %, particularly preferably 40 to 50 % of the material that is used for a corresponding height portion when generating a heating disk. This basically results in a variable height proportion of the support structure 40, which can be adapted depending on the material used and / or the honeycomb-like cell structure 26 of the heating disks 10 used, in particular the first heating disk 10 located directly above the support structure.

[0076] Thus, Fig. 4B shows a partial longitudinal cut through a lowermost heating disk 10 of the stack 20 according to the invention, together with an exemplary embodiment for the support structure 40 according to the invention as shown in Fig. 4A. The two sectional planes 1 -1 and 2-2 marked in Fig. 4B cut through the lowermost heating disk 10 (1 -1 ) on the one hand and through the support structure 40 (2-2) on the other hand. It is particularly clear from Fig. 4B that a changing cross-section may occur, especially in the transition region between the structure of the lowermost heating disk 10 and the support structure 40, in the present sectional view roof-shaped or triangular, although other alternatives are also conceivable, for example oblique or conical. In this context, Fig. 4C shows a cross-sectional view 1-1 of the lowermost heating disk 10 according to Fig. 4B and Fig. 4D shows a cross-sectional view 2-2 of the support structure 40 according to Fig. 4B. In particular, a direct comparison of heating disk 10 (Fig. 4C) and support structure 40 (Fig. 4D) clearly shows the extent to which material can be saved in support structure 40 compared to heating disk 10. Fig. 4D shows an embodiment of the support structure 40 in which only those cell walls that are perpendicular to the slots 14 have been additively manufactured. Furthermore, in contrast to the heating disk structure, the support structure 40 can comprise no grid substructure in order to create the flow openings 42 and thus open channels 28.

[0077] Reference is again made herein below to Fig. 2, which shows the stack 20 of unseparated heating disks 10 on the base 22 with the schematically indicated separation planes 24 between the individual heating disks 10 of the stack 20. While on the one hand it saves time and material to produce a stack 20 of heating disks 10 instead of just one heating disk 10 in one and the same additive manufacturing process, it is then necessary to separate the stack 20 into individual heating disks 10 with an exact, uniform and repeatable thickness.

[0078] In this context, it should be noted on the one hand that each form of separation entails a loss of material at or in the respective separation plane, which must be taken into account before the start of the melting method. The maximum height of a stack 20 to be produced therefore results not only from the respective thicknesses h of the individual heating disks 10 (plus an optional support structure 40 as shown in Figs. 3 to 4), but also from corresponding material additions for each separation process to be carried out later. On the other hand, when separating into individual heating disks 10, it is necessary to cut through all the material that is present at a corresponding position of a separation plane 24. The more material there is, the longer the separation process takes and the more expensive it is.

[0079] Separation or cutting can be carried out using a spark or wire erosion method (wire erosion), which is also preferred for such a fine-meshed structure. Both separation or cutting time and separation or cutting effort can be reduced if an additional spacer structure is installed between two heating disks. Compared to the cross-sectional shape of the heating disk, the spacer structure is reduced in terms of material. This leads to a lower material consumption in the corresponding area and thus to less effort for the separation process, and therefore also to a reduction in costs. Depending on the spacer structure, an average separation or cutting time can be approximately halved (duration for a cut without spacer structure approx. 20 min, duration for a cut with spacer structure approx. 10 min).

[0080] In this context, Fig. 5 shows a side view of two adjacent heating discs 10 of the stack 20 according to Fig. 2, which additionally provides an interposed spacer 50 according to the invention (marked in Fig. 5 by means of a frame). While only one spacer 50 is shown here between two exemplary adjacent heating disks 10, such a spacer 50 can be present between all adjacent heating disks 10 of a stack 20, respectively, each spacer 50 preferably at least partially connecting a lower heating disk to an upper heating disk in a production direction. Depending on an available installation space in the manufacturing device used, a stack 20 of heating disks 10 together with a respective spacer structure in-between, optionally also together with the support structure 40, can have a total manufacturing height of 30 to 80 cm, preferably 40 to 50 cm.

[0081] Figs. 6A and 6B further show cross-sectional views of two exemplary spacers according to Fig. 5. Analogous to the shape of the exemplary support structure 40 according to Fig. 4D, it can be asserted that the areas of the slots 14 are also sensibly omitted during production (for example sintering). Furthermore, for reasons of shape retention for heating disks located above and / or below, it can be useful to adumbrate the entire honeycomb cell structure 26, but to sinter it with a lower resolution. A lower resolution can already be achieved by the fact that a melting tool used as an example (e.g. a laser) does not scan or sample a corresponding structure twice (as in the case of the heating disks themselves, for example), but only once, in order to produce correspondingly thinner cell walls.

[0082] Fig. 7A shows a heating disk 10 according to the invention for an exhaust gas aftertreatment system comprising a locally varying cell density. The metallic heating disk 10 may be produced in a single manufacturing method. It comprises a large number of cells 12 with a honeycomb cell structure and locally different cell densities. It also comprises parallel, discontinuous slots 14 and two electrode arms 60. Regions with locally different cell densities can be advantageous, for example, at all those points on a heating disk 10 where it is necessary to control the current running from electrode to electrode (see Fig. 1 B in this context) in order to counteract premature wear of the heating disk 10. As shown in Fig. 7A, the locally increased cell density can preferably be present at the current turning points 16 in the area of the ends of the slots 14 located inside the heating disk.

[0083] In this context, Fig. 7B shows an enlarged partial view of the heating disk 10 as shown in Fig. 7A. While the individual cells of the plurality of cells 12 are being presented here in an exemplary rectangular format, the regions with locally increased cell density at the slot ends comprise square cell structures. Thus, all regions having a lower power density (low current flow) or inactive areas (no current flow) have the rectangular cell shape or cell structure. The high power density regions, such as the current turning points 16 in the area of the ends of the slots 14, have the quadratic cell shape or cell structure. As can be seen here, this already results in an exemplary regional doubling of the cell density by halving the plurality of cells 12 using additional crossbars. Moreover, Fig. 7C shows a sectional view along A-A as indicated in the heating disk 10 of Fig. 7B. As depicted, the heating disk 10 generally comprises a height h (or thickness) which is usually larger than a cell width a (shown in Fig. 7B). An exemplary thickness h of approx. 5 mm for the heating disk 10 could go well with an exemplary cell width a of approx. 1 .3 mm.

[0084] In the particular embodiment of Fig. 7C, the heating disk 10 combines rectangular cells, each having a length of 2a, with square or quadratic cells, each having a length of a, such that a length to width ratio of the rectangular cells is 2a:a or 2:1 . Alternatively, if the width of the cells is not equal to a (not shown), the heating disk 10 combines rectangular cells, each having a length of 2a, with square or quadratic cells, each having a length of a, such that a respective lengths ratio of the rectangular cells to the square cells is 2a:a or 2:1 .

[0085] In other words, when starting from an exemplary heating disk having a more or less pure square-celled pattern, the following applies: a reduction of mass by taking away crossbars (for instance each second crossbar resulting in the above described 2:1 ratio) in those regions that are not necessarily high power density regions (as for instance depicted in Figs. 7A to 7C) reduces both production time and costs. The functionality and service life of a resulting heating disc, however, is either not or at least not significantly reduced in comparison to heating disks comprising an only square or nearly square-celled pattern. While different length ratios, for instance 3:1 , may be possible as well, such a scenario might need repositioning the slots and / or changing the overall number of slots or changing their respective size in order to be able to depowder the resulting heating discs appropriately.

[0086] As an alternative to the embodiment according to Figs. 7A, 7B and 7C, Figs. 8A to 8D show further exemplary design alternatives of locally increased cell densities, whereby only a part of a heating disk at an exemplary slot end with different designs of locally increased cell density is depicted here, respectively. As in Figs. 7A and 7B, the correspondingly modified design with locally modified cell density and cell geometry also serves to homogenize the electrical current density and the energy density at the end of individual slots. The basic structure of the plurality of cells 12 is shown here as a particular example in a square format.

[0087] While Fig. 7A, which shows an entire exemplary heating disk 10, shows corresponding locally increased cell densities at all slot ends, such a configuration can also only be present at some, for example every second, slot end. Furthermore, it can be useful to combine different geometries, as shown in Figs. 8A to 8d, if the shape of the heating disk is not round but oval or elliptical, for example.

[0088] Moreover, similar to Figs. 7A to 7C and 8A to 8D, also Fig. 9 shows various configurations for flexible grid layouts of heating disks, which in principle are grid configurations a) to c) with flexible dimensions and with flexible layouts, all manufactured using the additive manufacturing methods of the present invention. One of the solution is to have, instead of only square and / or rectangular cells, also triangular cells.

[0089] Contrary to a fixed grid design over the entire diameter of a respective heating disk, such flexible grids as exemplarily depicted in Fig. 9 under a) to c), allow for an optimal balancing of parameters such as a maximum required heat flux into the exhaust gas, a potentially lowest backpressure, a suitable grid stiffness, a potentially lowest weight and potentially lowest production costs. One exemplary option is applying triangular cells or triangular cell pattern as depicted, i.e. with a same size or with different sizes over the width of the electrical heater. Another exemplary option is having bigger triangular cells on the edge of the electric heater and smaller triangular cells in the center, or opposite, or having smaller triangular cells on the edge and bigger triangular cells in the center. A further option is having cells with a combination of different shapes and sizes, e.g. triangular cells on the edge of the electric heater and square ones in the center, as depicted. In addition, an opposite configuration like square cells on the edge of the electric heater and triangular cells in the center is possible. There could also be a variation in sizes, equal size of square and triangular cells, or triangular cells can be smaller than square ones. These parameters apply to all examples a) to c) as depicted in Fig. 9 and may be freely combined. or not shown features

[0090] The present disclosure describes the presence of a support structure, a spacer structure and a locally increased cell density independently of each other. However, the aforementioned elements can be freely combined with each other, as required. The installation space available in a respective manufacturing device can contribute to the decision as to what extent all of the aforementioned features can be combined. In principle, the additive manufacturing methods according to the invention are ideal for combining the aforementioned features, as no other manufacturing method allows the aforementioned parameters to be easily adapted and implemented. Furthermore, products that have been produced using the methods according to the invention can be regarded as having been manufactured using additive manufacturing simply because all elements do not require additional connecting structures such as plugging, gluing, screwing, etc., as they have been produced in a single piece.

[0091] The present invention relates to the field of additive manufacturing, in particular metal-based additive manufacturing, whereby some exemplary, in particular direct, additive manufacturing methods have already been mentioned above. In the direct manufacturing of metal components, the metal component with fully- fledged properties is created directly by the additive structure. However, due to the complexity of the equipment (with lasers, galvo scanners, etc.) and special material requirements, the underlying investments are significantly higher than for plastics processing. However, the present invention is not necessarily limited to this. Rather, so-called indirect additive manufacturing can be considered, in which only a green product or green compact is produced by the underlying 3D printing, wherein a respective binder is later removed in furnace processes and sintered to the desired metal component if the dimensional stability and thus the resulting quality of the heating disks produced is maintained. This can be the case in particular for heating discs with a larger diameter and possibly lower cell density (for example, diameters over 200 mm comprising around 50 to 200 cells per square inch (approx. 8 - 31 cells / cm2)).

[0092] Typically, the methods of the present invention are used to print heating disks whose cell walls comprise a uniform wall thickness throughout, for example in the range from 50 to 250 pm. This wall thickness preferably lies in the range of 120 to 170 pm, particularly preferably around 150 pm. However, especially in the area of higher cell densities, preferably at the slot ends, the wall thickness of individual or several cells can also be increased as an alternative or in addition to changing the number of cells. Preferred wall thickness ranges are between about 1 .5 and 3.5 times the remaining cell walls of the plurality of cells.

[0093] Furthermore, the technical purpose of a heating disk for an exhaust gas aftertreatment system is basically to transfer heat to air and / or exhaust gas. The actual surface of the heating disk in three-dimensional space plays an important role in this context. More precisely, the transfer of heat energy from the heating disk matrix to the medium flowing through it (e.g. air or exhaust gas from an internal combustion engine) is heavily dependent on the available heat transfer surface, i.e. the surface that is in direct contact with and therefore in exchange with the medium flowing through it. Naturally, heating elements with a larger diameter or larger cross-sectional area have more surface area available. The cell density (number of cells / channels per proportion of the cross-sectional area of the heating element) can therefore be adjusted.

[0094] The following preferred value ranges can be used as a basis for a design: Diameter of disk vs. cell density (all figures approximate):

[0095] - up to 100 mm: 100-500 cells per square inch (15 - 77 cells / cm2)

[0096] - up to 150 mm: 75-400 cells per square inch (11 - 62 cells / cm2)

[0097] - up to 200 mm: 50-300 cells per square inch (8 - 46 cells / cm2)

[0098] - >200 mm: 50-200 cells per square inch (8 - 31 cells / cm2) The invention has been described with reference to preferred embodiments, whereby the individual features of the embodiments described can be freely combined with one another and / or interchanged, provided that they are compatible. Likewise, individual features of the described embodiments can be omitted if they are not technically necessary. Numerous modifications and embodiments are possible and obvious to the person skilled in the art without departing from the spirit of the invention.

[0099] Further examples of the invention An additive manufacturing method for at least one metallic heating disk for an exhaust gas aftertreatment system, the method comprising: additively generating a support structure on a base; and additively generating at least one heating disk on the support structure; wherein flow openings are formed between the base and the heating disk by means of the support structure; and wherein, together with internal openings of the at least one heating disk, the flow openings form a plurality of channels. The additive manufacturing method according to 1 , wherein the support structure comprises 20 to 70 %, preferably 35 to 55 %, particularly preferably 40 to 50 % of a material used for a corresponding height portion in the production of a heating disk. The additive manufacturing method according to 1 or 2, wherein the additive manufacturing method is a powder bed based melting; the method preferably further comprising a step of removing remaining powder particles; and wherein the step of removing is particularly preferably vibrating, shaking out, sucking out and / or blowing out of remaining powder particles along the plurality of channels. The additive manufacturing method according to any one of 1 to 3, wherein the at least one heating disk is a stack of heating disks; wherein the method preferably comprises a step of separating the generated stack of heating disks into individual heating disks; and wherein the step of separating is preferably carried out by means of spark erosion or wire erosion. The additive manufacturing method according to any one of 1 to 4, further comprising: grinding and / or milling off the support structure and / or the surfaces of the heating disks separated from each other; and / or removing the support structure by means of spark or wire erosion.

[0100] 6. An additive manufacturing method for metallic heating disks for exhaust aftertreatment systems, the method comprising: additively generating a stack of heating disks, each comprising a spacer structure between the individual heating disks in the stack of heating disks; wherein the spacer structure has a height (H); and wherein a material used to generate each spacer structure of the height (H) corresponds to 20 to 70% of a material used for a corresponding height portion when generating a heating disk.

[0101] 7. The additive manufacturing method according to 6, further comprising a step of separating the generated stack of heating disks into individual heating disks at an area of the spacer structure; wherein the step of separating step takes place in the area of the spacer structure, preferably by means of spark erosion, particularly preferably by means of wire erosion.

[0102] 8. The additive manufacturing method according to 6 or 7, wherein the spacer structure is formed by a plurality of parallel ribs.

[0103] 9. The additive manufacturing method according to any one of 6 to 8, wherein the height (H) of each spacer structure is between 0.2 to 3 mm, preferably between 0.2 to 1 mm, more preferably between 02 to 0.4 mm.

[0104] 10. The additive manufacturing method according to any one of 7 or 9 in combination with claim 7, wherein a wire used in wire EDM has a diameter between 0.1 to 0.4 mm, preferably between 0.18 to 0.3 mm. 11 . The additive manufacturing method according to any one of 6 to 10, wherein the material used for generating each spacer structure corresponds to 35 to 55%, preferably 40 to 50%, of the material used for the corresponding height portion in the production of a heating disk.

[0105] 12. The additive manufacturing method according to any one of 6 to 11 , wherein the step of generating the stack of heating disks further comprises: additively generating a support structure between a base, to form flow openings between the support structure and the base, and the lowermost heating disk of the stack of heating disks; wherein the flow openings form a plurality of channels having internal openings.

[0106] 13. The additive manufacturing method according to any one of 6 to 12, wherein the spacer structure between each heating disk is different from the support structure.

[0107] 14. The additive manufacturing method according to any one of 6 to 13, wherein the method further comprises a step of grinding and / or milling off residues of the spacer structure remaining after the step of separating.

[0108] 15. An additive manufacturing method for at least one metallic heating disk for an exhaust gas aftertreatment system, the method comprising: additively generating at least one heating disk comprising: a large number of cells comprising a honeycomb cell structure; parallel non-continuous slots; and locally different cell densities.

[0109] 16. The additive manufacturing method according to 15, wherein the locally different cell density comprises locally increased cell densities on the heating disk, preferably at current turning points in the region of slot ends located in the interior of the heating disk, wherein locally increased cell densities at the slot ends are particularly preferably present at most in the range of 1 / 10 to 1 / 4 of the total slot length of a shortest slot.

[0110] 17. The additive manufacturing method according to 15 or 16, wherein the locally varying cell density of the heating disk is defined by at least one of the following parameters: a locally reduced cell size of one or more cells; a locally altered cell shape of one or more cells; a local combination of different altered cell forms; and an increased wall thickness of individual cells.

[0111] 18. The additive manufacturing method according to any one of 15 to 17 wherein the locally varying cell density of the heating disk comprises that the number of cell walls is locally increased by a factor of 1 .5 to 3.5 compared to the remaining cell walls; the locally varying cell density preferably comprising an average cell density of 62 to 124 cells / cm2(400 to 800 cells per square inch).

[0112] 19. The additive manufacturing method according to any one of 15 to 18, wherein the at least one heating disk is a stack of heating disks.

[0113] 20. The additive manufacturing method according to 19, the method further comprising a step of separating the generated stack of heating disks into individual heating disks; and wherein the step of separating is preferably carried out by spark erosion, particularly preferably by wire erosion.

[0114] 21 . The additive manufacturing method according to any one of 1 to 20, wherein the material of the at least one heating disk comprises a permanent temperature resistance of 850 to 1000°C, preferably of 900 to 950°. The additive manufacturing method according to any one of 1 to 21 , wherein the material of the at least one heating disk is a Ni-based material, an iron-chromium-aluminum material, an austenitic steel material or a ferritic steel material. The additive manufacturing method according to any one of 1 to 22, wherein the step of additively generating the at least one heating disk or stack of heating disks comprises additively generating two electrode arms in the same generation step. The additive manufacturing method according to any one of 1 to 23, wherein the additive manufacturing method provides for manufacturing the at least one metallic heating disk in a horizontal orientation relative to the base. The additive manufacturing method according to any one of 1 to 24, wherein the additive manufacturing method is a powder bed based melting method, preferably laser sintering, laser beam melting, electron beam melting, binder jetting and / or thermal transfer sintering. The additive manufacturing method according to any one of 1 to 25, further comprising: removing remaining powder particles, preferably by vibrating, shaking out, sucking out and / or blowing out, particularly preferably from one or two sides of the stack of heating discs or from each of the at least one metallic heating disks. The additive manufacturing method according to any one of 1 to 26, wherein the at least one heating disk comprises a honeycomb cell structure comprising cells preferably having a triangular, square, rectangular, pentagonal, hexagonal, polygonal structure or any combination thereof. The additive manufacturing method according to any one of 1 to 27, wherein the heating disk comprises a honeycomb cell structure which comprises a meandering structure which is preferably formed by parallel non-continuous slots, the slots extending particularly preferably alternately from the outer circumference of the heating disk starting into the interior of the disk. The additive manufacturing method according to any one of 1 to 28, wherein the at least one heating disk has a diameter of 200 to 250 mm, preferably of 200 to 220 mm, with an average cell density of 8 to 31 cells / cm2(50 to 200 cells per square inch), preferably of 14 to 18 cells / cm2(90 to 180 cells per square inch). The additive manufacturing method according to any one of 1 to 29, wherein the at least one heating disk has a diameter of 150 to 200 mm, preferably of 150 to 180 mm, with an average cell density of 8 to 46 cells / cm2(50 to 300 cells per square inch), preferably of 8 to 15 cells / cm2(50 to 200 cells per square inch). The additive manufacturing method according to any one of 1 to 26, wherein the at least one heating disk has a diameter of 100 to 150 mm, preferably of 100 to 110 mm, with an average cell density of 11 to 60 cells / cm2(75 to 400 cells per square inch), preferably of 15 to 38 cells / cm2(100 to 250 cells per square inch). The additive manufacturing method according to any one of 1 to 31 , wherein the at least one heating disk has a height of 4 to 10 mm, preferably of 4.5 to 7 mm, particularly preferably in relation to the diameter of the heating disk. 33. A heating disk produced using one of the previous additive manufacturing methods.

[0115] 34. The heating disk according to 33, wherein the heating disk comprises a nominal power of up to 15 KW with a diameter of up to 200 mm; or wherein the heating disk comprises a nominal output of up to 25 kW with a diameter of up to 300 mm.

[0116] List of reference symbols

[0117] 10 Heating disk

[0118] 12 Plurality of cells

[0119] 14 Plurality of slots

[0120] 16 Current turning point

[0121] 20 Stack

[0122] 22 Base

[0123] 24 Separating planes

[0124] 26 Honeycomb cell structure

[0125] 28 Plurality of channels

[0126] 30 Powder removal mechanism

[0127] 32 Particles

[0128] 40 Support structure

[0129] 42 Flow openings

[0130] 50 Spacer I spacer structure

[0131] 60 Electrode arm h Height I thickness of a heating disk d Diameter of a heating disk

[0132] H Height of a spacer structure

Claims

Claims1 . An additive manufacturing method for at least one metallic heating disk for an exhaust gas aftertreatment system, comprising: additively generating at least one heating disk comprising: a large number of cells comprising a honeycomb cell structure; parallel non-continuous slots; and locally different cell densities.

2. The additive manufacturing method according to claim 1 , wherein the locally different cell density comprises locally increased cell densities on the heating disk, preferably at current turning points in the region of slot ends located in the interior of the heating disk, wherein locally increased cell densities at the slot ends are particularly preferably present at most in the range of 1 / 10 to 1 / 4 of the total slot length of a shortest slot.

3. The additive manufacturing method according to claim 1 or 2, wherein the locally varying cell density of the heating disk is defined by at least one of the following parameters: a locally reduced cell size of one or more cells; a locally altered cell shape of one or more cells; a local combination of different altered cell forms; and an increased wall thickness of individual cells.

4. The additive manufacturing method according to any one of the preceding claims, wherein the locally different cell density of the heating disk comprises that the number of cell walls is locally increased to 1 .5 times to 3.5 times compared to the remaining cell walls; wherein an average cell density of 62 to 124 cells / cm2(400 to 800 cells per square inch) is preferred.

5. The additive manufacturing method according to any one of the preceding claims, wherein the at least one heating disk is a stack of heating disks.

6. The additive manufacturing method according to claim 5, the method further comprising a step of separating the generated stack of heating disks into individual heating disks; and wherein the step of separating is preferably carried out by spark erosion, particularly preferably by wire erosion.

7. The additive manufacturing method according to any one of claims 5 or 6, wherein the step of generating the stack of heating disks further comprises: additively generating a support structure between a base, to form flow openings between the support structure and the base, and the lowermost heating disk of the stack of heating disks; wherein the flow openings form a plurality of channels with internal openings of the stack of heating disks.

8. The additive manufacturing method according to any one of claims 5 to 7, further comprising: additively generating the stack of heating disks with a spacer structure between each individual heating disk in the stack of heating disks; wherein the spacer structure has a height (H); and wherein the material used to generate each spacer structure in the height (H) corresponds to 20 to 70% of the material used for a corresponding height portion in generating a heating disk.

9. The additive manufacturing method according to any one of the preceding claims, wherein the material of the at least one heating disk comprises a permanent temperature resistance of 850 to 1000 °C, preferably 900 to 950°.

10. The additive manufacturing method according to any one of the preceding claims, wherein the material of the at least one heating disk is a Ni-based material, an iron-chromium-aluminum material, an austenitic steel material or a ferritic steel material.11 . The additive manufacturing method according to any one of the preceding claims, wherein the step of additively generating the at least one heating disk or stack of heating disks comprises additively generating two electrode arms in the same generation step.

12. The additive manufacturing method according to any one of the preceding claims, wherein the additive manufacturing method provides for manufacturing the at least one metallic heating disk in lying and / or in a horizontal orientation relative to the base.

13. The additive manufacturing method according to any one of the preceding claims, wherein the additive manufacturing method is a powder bed based melting method, preferably laser sintering, laser beam melting, electron beam melting, binder jetting and / or thermal transfer sintering.

14. The additive manufacturing method according to any one of the preceding claims, further comprising a step of removing remaining powder particles, preferably by vibrating, shaking out, sucking out and / or blowing out, particularly preferably from one or two sides.

15. The additive manufacturing method according to any one of the preceding claims, wherein the at least one heating disk comprises a honeycomb cell structure comprising cells preferably comprising a triangular, square or quadratic, rectangular, pentagonal, hexagonal, polygonal structure or any combination thereof.

16. The additive manufacturing method according to any one of the preceding claims, wherein the heating disk comprises a honeycomb cell structure which comprises a meandering structure preferably formed by the parallel discontinuous slots, the slots extending particularly preferably alternately from the outer periphery of the heating disk starting into the interior of the disk.

17. The additive manufacturing method according to any one of the preceding claims, wherein the at least one heating disk has a diameter of 200 to 250 mm, preferably 200 to 220 mm, with an average cell density of 8 to 31 cells / cm2(50 to 200 cells per square inch), preferably 14 to 18 cells / cm2(90 to 180 cells per square inch).

18. The additive manufacturing method according to any one of claims 1 to 16, wherein the at least one heating disk has a diameter of 150 to 200 mm, preferably 150 to 180 mm, with an average cell density of 8 to 46 cells / cm2(50 to 300 cells per square inch), preferably 8 to 15 cells / cm2(50 to 200 cells per square inch).

19. The additive manufacturing method according to any one of claims 1 to 16, wherein the at least one heating disk has a diameter of 100 to 150 mm, preferably 100 to 110 mm, with an average cell density of 11 to 60 cells / cm2(75 to 400 cells per square inch), preferably 15 to 38 cells / cm2(100 to 250 cells per square inch).

20. The additive manufacturing method according to any one of the preceding claims, wherein the at least one heating disk has a height of 4 to 10 mm, preferably 4.5 to 7 mm, particularly preferably relative to the diameter of the heating disk.21 . A heating disk manufactured using one of the preceding additive manufacturing methods.

22. The heating disk according to claim 21 , wherein the heating disk comprises a rated power of up to 15 KW at a diameter of up to 200 mm; or wherein the heating disk comprises a nominal output of up to 25 kW with a diameter of up to 300 mm.

23. A metallic heating disk for an exhaust gas aftertreatment system produced in a single manufacturing method, comprising the following: a large number of cells with a honeycomb cell structure and locally varying cell densities; parallel non-continuous slots; and two electrode arms.

24. The metallic heating disk according to claim 23, wherein the locally different cell density comprises locally increased cell densities on the heating disk, preferably at current turning points in the region of slot ends located in the interior of the heating disk, wherein locally increased cell densities at the slot ends are particularly preferably present at most in the range of 1 / 10 to 1 / 4 of the total slot length of a shortest slot.

25. The additive manufacturing method according to claim 15 or the metallic heating disk according to claim 23 or 24, wherein the at least one heating disk further comprises: rectangular cells in non-active areas and in low power and / or low current density areas; and quadratic or square cells in high power and / or high current density areas, preferably close to a current turning point; wherein rectangular cells preferably comprise a length to width ratio of 2:1.

26. The additive manufacturing method according to claim 15 or the metallic heating disk according to claim 23 or 24, wherein the at least one heating disk further comprises: a grid of triangular cells, either alone or in combination with square and / or rectangular pattern; wherein preferably the grid of triangular cells comprises triangular cells of same or different sizes, preferably having smaller cells in the center and bigger cells on the edges or smaller cells on the edge and bigger cells in the center.

27. The metallic heating disk according to any one of claims 21 to 26, wherein the locally different cell density of the heating disk comprises that the number of cell walls is locally increased by a factor of 1 .5 to 3.5 compared to the remaining cell walls; preferably comprising an average cell density of 62 to 124 cells / cm2(400 to 800 cells per square inch).

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