METHOD FOR CONSTRUCTING A BUILDING WALL USING 3D PRINTING

Description

[0001] The invention relates to a method for constructing a building wall using 3D printing. An example of such a method is described in WO 2020 / 252532 A1.

[0002] 3D printing enables the sequential construction of objects by placing material point by point or line by line along a given or predeterminable path in space. The material is typically a plastic that is, or is made, plastically deformable and hardens as quickly as possible after being placed in space. Typically, the material is applied from a base in several successive layers from bottom to top, so that still-deformable material is applied to already hardened or at least sufficiently solid structures made of previously placed material and is then supported by these while it hardens.

[0003] This basic principle, which is already largely established for smaller objects and is widely used, can in principle also be transferred to very large scales. It is now possible to construct building elements or even entire buildings using 3D printing. A key factor for this possibility is the use of a suitable building material that, on the one hand, is initially sufficiently plastically deformable to be guided to a specific point in space and applied there to an existing structure or previously placed building material, and, on the other hand, has sufficient strength as soon as possible to maintain its position and harden in this position with good bonding to its substrate. Special concretes that exhibit these properties are now available as building materials for 3D printing building elements.

[0004] Various parameters of the respective building element, such as stability, thermal insulation, acoustics, the speed at which the building element can be erected, and production costs, depend not only on the building material used, but also on the design and structure of the respective building element. For building walls, it can be particularly useful to use 3D printing to create double-walled walls with a free space between them. This involves 3D printing two opposing wall surfaces of the respective building wall (as well as, if applicable, end faces of the building wall that connect the two wall surfaces at their lateral ends), leaving a gap between these wall surfaces. This free space can then be subsequently filled using conventional concrete, which can, for example, simply be poured into the free space.In addition or alternatively, other materials can be used to fill the open space, such as those with particularly advantageous thermal insulation and / or acoustic properties. Furthermore, parts of the open space can also be left free, for example, for the installation of electrical or plumbing installations.

[0005] However, it is fundamentally important that 3D-printed wall surfaces exhibit high stability. For building walls made of concrete poured into a formwork, it is common practice to provide reinforcement bars within the formwork, which can be arranged, for example, in a grid-like manner. These reinforcement bars are then cast into the concrete and improve the stability of the building wall. However, such conventional concrete reinforcement would hinder 3D printing, as the reinforcement bars or such a grid structure of reinforcement bars would block the path along which the respective building material is applied during 3D printing.

[0006] It is an object of the invention to provide a method for erecting a building wall using 3D printing, with which a stable building wall with advantageous properties can be erected in a flexible and largely automated manner.

[0007] The invention is achieved by a method having the features of claim 1. Advantageous embodiments emerge from the dependent claims, the present description and the figures.

[0008] The method according to the invention comprises: providing a 3D positioning device with a tool holder to which a print head is attached; supplying a building material that is initially plastically deformable and then hardens to the print head; and applying the building material along a predetermined or predeterminable printing path by means of the print head, in which the print head is moved along the printing path by means of the 3D positioning device, thereby dispensing the building material, in particular as a material strand. Dispensing can occur, for example, by forcing the building material out of a nozzle of the print head.

[0009] The 3D positioning device can, in particular, be a gantry robot. This can comprise a traverse that extends along a first horizontal direction and is mounted so as to be adjustable in a second horizontal direction running transversely, in particular orthogonally, thereto, as well as in the vertical direction. The tool holder can then be movable along the traverse and thus be at least substantially freely positionable within a specific spatial volume defined by the mobility of the tool holder along the first horizontal direction and the mobility of the traverse along the second horizontal direction and the vertical direction. In this way, the print head attached to the tool holder can also be moved along the aforementioned printing path, which runs within the aforementioned spatial volume.

[0010] As an alternative to a gantry robot, an articulated arm robot or another movement system, particularly known from mechanical engineering, can be used as a 3D positioning device, which can move a print head attached to it along a predetermined or predeterminable print path.

[0011] The said building material can be continuously fed to the print head. For this purpose, the building material can in principle be stored in a container, such as a tank, which is carried along with the print head and can be attached to the print head or to the tool holder for this purpose. Preferably, however, the building material is fed externally, for example via a hose which is fed, for example, by a concrete pump. The building material is expediently initially plastically deformable, i.e. before and during application, but already has sufficient stability to then (after emerging from the print head) retain its position and at least largely also its shape while it hardens. The building material can in particular be concrete.

[0012] According to the invention, said printed web runs in several horizontal layers that are vertically offset parallel to one another. Said several horizontal layers do not necessarily have to include all horizontal layers in which the printed web runs as a whole. For the inventive method for erecting the building wall, only those layers of the printed web within which the building wall extends are considered. The printed web can run, in particular above and optionally also below the building wall (to be erected), in further horizontal layers that are not encompassed by said several horizontal layers and are not considered further here.The fact that the printing path runs in layers means in particular that the printing path (apart from possible transitions between the layers) can be divided into sections, each of which lies entirely within a respective one of the horizontal layers and thus in turn has an at least essentially horizontal course.

[0013] By running in horizontal layers, 3D printing can be carried out layer by layer, whereby the bottom layer is first passed through according to the section of the print path that runs through it, and the building material is applied along this section to a substrate or foundation. The building material can then be applied layer by layer from bottom to top to the previously dispensed building material. The layers do not necessarily have to be exactly horizontal, but preferably they are at least essentially horizontal. In addition, the layers are preferably distributed evenly in the vertical direction, so that adjacent layers are each at the same distance from one another, which is expediently at least essentially the thickness (extension in the vertical direction) of the material strand dispensed from the print head.

[0014] The print path can be discontinuous in that it can have interruptions within which the print head is moved but does not dispense any building material. Such an interruption can be particularly useful during the transition from one layer to the next. Furthermore, such interruptions can be provided to create recesses in the building wall, such as a window or door, or openings for electrical or plumbing installations. Furthermore, the print path can be interrupted so that functions other than applying building material can be performed in between using the same 3D positioning device.

[0015] Furthermore, according to the invention, the printing web comprises a respective first section in each of the said layers (i.e. the said plurality of layers within which the building wall extends) to form a first wall surface of the building wall. In this respect, the building material applied in the said layers along the respective first section can then form the first wall surface as a whole. The designation of the wall surface as the first wall surface and the designation of the first section as the first section only serve to conceptually distinguish between any further wall surfaces and sections that may be provided, but does not imply that the building wall necessarily comprises one or more further wall surfaces or that the printing web necessarily comprises one or more respective further sections in each of the said layers (to form one or more further wall surfaces of the building wall).

[0016] Similar to the printing web as a whole, the respective first section can also be discontinuous, i.e. have interruptions. In principle, the print head can be moved along another section of the printing web (running in the same or another of the multiple layers) within such an interruption of the respective first section and in the process dispense the building material. However, during such an interruption of the respective first section, building material is preferably not dispensed along another section of the printing web. The respective first section preferably has a course that is at least approximately continuous in that two subsections into which it is divided at a respective interruption are at least substantially aligned with one another. In particular, the entire respective first section can run along a straight line.

[0017] According to the invention, the method further comprises providing at least one elongate reinforcing element which extends along a longitudinal direction, has a first side transverse to the longitudinal direction and a second side opposite thereto, and has at least one through-opening which connects the two sides (i.e. the first side and the second side) to one another. The reinforcing element preferably has an at least substantially constant cross-section (in particular apart from through-openings running transversely to the longitudinal direction). Said first side can in particular be oriented pointing in a transverse direction orthogonal to the longitudinal direction, while the second side is then oriented counter to the transverse direction, i.e. in the direction opposite to the transverse direction.The at least one through-opening can extend through the reinforcement element, in particular transversely to the longitudinal direction, preferably parallel to said transverse direction. Furthermore, it can connect the first side and the second side of the reinforcement element, in particular insofar as it is possible for the building material to pass through the at least one through-opening from the first side to the second side and / or vice versa. The reinforcement element preferably has a plurality of through-openings, which can be arranged, in particular, regularly distributed over the entire longitudinal extent of the reinforcement element.

[0018] According to the invention, the method further comprises fixing the at least one reinforcing element vertically aligned (with respect to its longitudinal extent along the longitudinal direction) to a substrate such that it crosses the respective first section in at least some of the layers, so that a first subsection of the first section adjoins one of the two mentioned sides of the reinforcing element and a second subsection of the first section adjoins the other of the two mentioned sides of the reinforcing element. The substrate can be, for example, a foundation or an already constructed floor of a building. The reinforcing element can be fastened directly to this substrate for the aforementioned fixing.The reinforcement element can also be fixed to the substrate by first applying a few layers of building material along the respective first section and then inserting the reinforcement element with one of the ends of its longitudinal extension into the already applied building material.

[0019] The aforementioned at least some of the layers in which the vertically aligned, fixed reinforcement element crosses the respective first section are, in particular, a number of vertically adjacent layers starting from the subsurface corresponding to the length (longitudinal extension) of the reinforcement element (possibly less existing layers into which the reinforcement element has been inserted for fixing). In principle, it is also conceivable for the aforementioned at least some of the layers to comprise all of the aforementioned multiple layers within which the building wall extends.

[0020] According to the invention, the method further comprises that the print head in at least one of the layers (ie one of said at least some of the layers), after (in particular immediately after) the print head has been moved along the first sub-section towards the respective side of the reinforcing element (ie the side of the reinforcing element adjacent to the first sub-section) and has dispensed building material in the process and / or before (in particular immediately before) the print head has been moved along the second sub-section away from the respective side of the reinforcing element (ie the side of the reinforcing element adjacent to the second sub-section) and has dispensed building material in the process, presses building material through the at least one through-opening onto the respective other side of the reinforcing element.The pressing takes place in at least one of the at least several layers in which the reinforcing element crosses the respective first section, and can also take place in several different ones. Preferably, it takes place in all of these layers. However, this is not necessarily the case.

[0021] Even if the pressure head cannot pass through or penetrate the reinforcement element, the aforementioned pressing process allows the building material applied on one side of the reinforcement element and the building material applied on the other side of the reinforcement element to bond through the reinforcement element into a continuous, uniform mass before the material has hardened. Reliable penetration of the reinforcement element is ensured, in particular, by using the pressure head to press building material through at least one through-hole.

[0022] For this purpose, it can be provided, for example, that the print head applies building material in a respective one of the at least some layers on one of the sides of the reinforcing element and is moved along the first partial section up to the at least one through-opening, then continues to dispense building material for a certain period of time without being moved in order to thereby press the building material through the at least one through-opening of the reinforcing element; subsequently, the print head can be moved to the other side of the reinforcing element while the dispensing of building material is paused, and then dispense building material again while being moved along the second partial section away from the at least one through-opening.Alternatively, it can be provided that the print head applies building material in a respective one of the at least some layers on one of the sides of the reinforcing element and is moved along the first section up to the at least one through-opening, but then does not dispense any further building material there, but is moved to the other side of the reinforcing element and there up to the at least one through-opening without dispensing building material; the print head can then dispense building material for a certain period of time without being moved in order to thereby press the building material through the at least one through-opening of the reinforcing element, before it is moved along the second section away from the at least one through-opening and continues to dispense building material.Finally, it is also conceivable in principle that (at least initially) only on one of the two sides of the reinforcement element, building material is applied along the respective section towards the reinforcement element and / or away from the reinforcement element and is pressed through the at least one through-opening of the reinforcement element to the other side of the reinforcement element.

[0023] The at least one through-opening is preferably sized to allow easy penetration of the building material. The reinforcing element preferably has a plurality of through-openings. It is preferred if the through-openings account for at least 30%, in particular at least 50%, of the total area of ​​the reinforcing element in cross-section orthogonal to the first subsection and / or the second subsection.

[0024] The reinforcement element is preferably rigid and has a high degree of strength. The reinforcement element can be made of plastic and / or metal, such as steel. Carbon fiber materials and glass fiber materials are also possible materials for the reinforcement element.

[0025] According to an advantageous embodiment, the reinforcing element is designed as a profile that extends with an at least substantially constant cross-section along the longitudinal direction. The profile is preferably made of metal, in particular of a metal sheet. To form the profile, the metal sheet can be bent, in particular at one or more edges running parallel to the longitudinal direction. The use of profiles makes it possible to use components for the 3D printing of a building wall that are known and available from other contexts, namely from drywall construction and / or lightweight steel construction. Furthermore, profiles can be manufactured with comparatively little effort.

[0026] According to a further advantageous embodiment, the reinforcing element has a web section that extends along the longitudinal direction, preferably over the entire length (extension in the longitudinal direction) of the reinforcing element, and is oriented orthogonally to the first subsection and / or the second subsection when the reinforcing element is fixed to the substrate; the at least one through-opening is formed in the web section. The web section is preferably flat. The at least one through-opening can then be formed in the web section, for example, by punching.

[0027] In principle, the web section can form the entire reinforcement element. For example, the reinforcement element can be designed as a flat metal sheet strip that corresponds to the web section. Preferably, however, the reinforcement element also has additional sections.

[0028] According to an advantageous development of the above embodiment, the reinforcing element has one or more flange sections that extend along the longitudinal direction, preferably over the entire length of the reinforcing element, and are aligned orthogonally to the web section. The flange sections can in particular be flat. Preferably, two flange sections are provided, which are arranged in the cross-section of the reinforcing element (orthogonal to the longitudinal direction) at opposite ends of the web section. One or more such flange sections can improve the flexural and torsional rigidity as well as the overall stability of the reinforcing element. Furthermore, bead structures embossed into the profile, in particular along the longitudinal direction and / or transversely thereto, can further improve the stability of the profile and thus the bond with the building material.

[0029] If the reinforcing element is designed as a profile as explained above, according to a further advantageous embodiment, the cross section of the profile can have a C-shape, U-shape or H-shape with a web section and two flange sections oriented perpendicular thereto, wherein the at least one through-opening is formed in the web section. In particular, the at least one through-opening can therefore be formed in the base of the C-shape or U-shape opposite the respective opening of the C-shape or U-shape or in the connecting web of the H-shape arranged between the two openings of the H-shape. The web section and the flange sections can in particular be formed in one of the ways described above.

[0030] According to an advantageous development of one of the embodiments described above, in which the reinforcing element has flange sections, the building material is applied in such a way that at least one of the flange sections remains accessible from outside the building wall. If the reinforcing element is designed as a profile with a C-shaped, U-shaped, or H-shaped cross-section, it can be provided in particular that the building material is dispensed from the pressure head into the interior of the C-shape, U-shape, or H-shape and pressed through the web section, but one or both flange sections remain free from the outside. This allows the respective flange section to be available, for example, for attaching other elements to the wall surface.

[0031] According to a further advantageous embodiment, the method further comprises: providing a further elongate reinforcing element which extends along a longitudinal direction (of the further reinforcing element), has a first side transverse to the longitudinal direction and a second side opposite thereto, and has at least one through-opening which connects the two sides to one another;that the further elongated reinforcing element, after the print head has applied building material in said at least some of the layers along the respective first section, is fastened to the said reinforcing element in an extension of the latter in such a vertically aligned manner that it crosses the respective first section in at least some of the further layers, so that in each case a first partial section of the first section adjoins one of the two sides of the further reinforcing element and a second partial section of the first section adjoins the other of the two sides of the further reinforcing element;and that the print head in at least one of the layers (i.e. one of the said at least some further layers), after (in particular immediately after) the print head has been moved along the first sub-section towards the respective side of the further reinforcing element (i.e. the side of the further reinforcing element to which the first sub-section is adjacent) and has dispensed building material in the process and / or before (in particular immediately before) the print head has been moved along the second sub-section away from the respective side of the further reinforcing element (i.e. the side of the further reinforcing element to which the second sub-section is adjacent) and has dispensed building material in the process, presses building material through the at least one through-opening of the further reinforcing element onto the respective other side of the further reinforcing element.;

[0032] By means of such a further reinforcement element, the said reinforcement element can consequently be extended in order to form a building wall whose height is greater than the length of the said reinforcement element. In this respect, the further method with regard to the further reinforcement element essentially corresponds to the procedure for the said reinforcement element, the main difference being that the further reinforcement element is not fixed to a substrate, but is attached to the said reinforcement element and therefore crosses the respective first section not in the same at least some of the layers, but in at least some further layers in which the printing web runs. The further reinforcement element can in particular be designed to be structurally identical to the said reinforcement element.Even if it is not constructed in the same way as the said reinforcing element, the further reinforcing element can be constructed and used in particular in a manner described for the said reinforcing element.

[0033] The additional reinforcement element can be attached to the aforementioned reinforcement element in a generally known manner. In particular, if the aforementioned reinforcement element and the additional reinforcement element are each designed as a profile, a profile connector, for example, can be used for the attachment. Such a profile connector can be designed such that one end (the upper end) of the aforementioned reinforcement element and one end (the lower end) of the additional reinforcement element can be inserted therein from opposite sides, or conversely, can be designed to be inserted partially into the aforementioned end of the aforementioned reinforcement element and partially into the aforementioned end of the additional reinforcement element, so that it holds the aforementioned reinforcement element and the additional reinforcement element in an aligned arrangement.

[0034] According to an advantageous development of the above embodiment, the further reinforcement element is fastened to the aforementioned reinforcement element by means of a profile connector, which in turn has at least one through-opening, in such a way that the at least one through-opening of the profile connector overlaps with the at least one through-opening of the reinforcement element and / or with the at least one through-opening of the further reinforcement element. Due to the overlap, it is then advantageously also possible in the region of the profile connector for the building material to penetrate from one side of the reinforcement element or of the further reinforcement element through the overlapping through-openings to the opposite side.

[0035] According to a further advantageous embodiment, not only a single reinforcing element is provided, but several reinforcing elements of the type mentioned are provided, ie several reinforcing elements which are each designed in a corresponding manner to the reinforcement element mentioned, and not only a single further reinforcing element is provided, but several further reinforcing elements of the type mentioned are provided, ie several further reinforcing elements which are each designed in a corresponding manner to the described further reinforcing element. In particular, each of the several reinforcing elements is then fixed to the substrate in the manner mentioned, ie the manner described for the individual reinforcement element, and each of the several further reinforcing elements is then fixed to the substrate in the manner mentioned, iethe manner described for the individual further reinforcement element, in an extension of a respective one of the said plurality of reinforcement elements, so that two or more reinforcement elements are connected to one another in extensions to one another. Furthermore, it can then be provided in particular that the pressure head presses building material through the at least one through-opening of the respective reinforcement element in the manner described for the individual reinforcement element with respect to each of the plurality of reinforcement elements, and that the pressure head presses building material through the at least one through-opening of the respective further reinforcement element in the manner described for the individual further reinforcement element with respect to each of the plurality of further reinforcement elements.

[0036] In this embodiment, it is further provided that the lengths of the plurality of reinforcement elements differ, so that the fastening of the plurality of further reinforcement elements to one of the said plurality of reinforcement elements takes place at different heights, i.e. at different vertical distances from the substrate. Since the stability of the wall surface in the region of the fastening of a respective one of the plurality of further reinforcement elements to a respective one of the said plurality of reinforcement elements can be comparatively lower than in regions in which a respective reinforcement element or further reinforcement element extends continuously, such an embodiment avoids such regions of lower stability all being at the same height and the wall surface thus being weakened along a continuous horizontal line.

[0037] According to a further advantageous embodiment, the method further comprises: providing an elongate transverse reinforcement element which extends along a longitudinal direction (of the transverse reinforcement element), has a first side and an opposite second side transverse to the longitudinal direction, and has at least one through-opening which connects the two sides to one another; and applying the transverse reinforcement element, after the print head has applied building material in at least one of the further layers along the respective first section, in a horizontally aligned manner (with respect to its longitudinal extent along the longitudinal direction), to the applied building material and preferably coupled to the aforementioned (vertically fixed) reinforcement element. The transverse reinforcement element can in particular be structurally identical to the aforementioned reinforcement element.Even if it is not constructed identically to the said reinforcement element, the transverse reinforcement element can be constructed in particular in a manner described for the said reinforcement element.

[0038] Applying the transverse reinforcement element to the applied building material can involve the transverse reinforcement element at least partially sinking or being pressed into the building material, so that the building material can penetrate through the at least one through-opening of the transverse reinforcement element. Furthermore, in the subsequent layer, i.e., in the layer immediately above it vertically, the printing web, the building material is then applied to the horizontal transverse reinforcement element and can thus come into contact with the building material of the underlying layer through the at least one through-opening, so that the transverse reinforcement element can contribute to the stability of the wall surface without interfering with a cohesive, continuous structure of the (ultimately cured) building material through the various layers.

[0039] The coupling of the transverse reinforcement element to the aforementioned reinforcement element can be achieved, for example, by simply inserting one into the other. In particular, if the aforementioned reinforcement element is designed as a profile with a U-shaped, C-shaped, or H-shaped cross-section, one end (with respect to the longitudinal extent) of the transverse reinforcement element can be inserted into the profile through the opening of the U-shape or C-shape or one of the openings of the H-shape. The coupling does not have to be specifically secured against loosening, since the hardening building material already ensures fixation. Preferably, however, the transverse reinforcement element and the aforementioned reinforcement element are coupled in such a way that they are held in a relative alignment to one another, in particular orthogonally to one another.For example, a firm connection between the reinforcement element and the transverse reinforcement element can be created by screwing, riveting or crimping in order to increase the strength and rigidity of the building wall to be constructed.

[0040] In principle, the building wall can have more than just one wall surface, wherein each of the wall surfaces can be designed in the manner according to the invention on its own and in principle independently of the other wall surfaces of the same building wall. In other words, it can be provided that the said at least one reinforcing element is arranged exclusively (at least partially) within the said first wall surface, but not also in a further wall surface. However, it can also be provided that the building wall comprises several wall surfaces and that the said at least one reinforcing element extends over at least two of these wall surfaces and is thus arranged partly in one wall surface and partly in the other wall surface, as explained below.

[0041] According to a further advantageous embodiment, the printing track for forming a second wall surface of the building wall comprises in each of the said layers (ieof said plurality of layers within which the building wall extends) a respective second section, wherein the at least one reinforcing element is fixed vertically aligned on a substrate in such a way (with respect to its longitudinal extent along the longitudinal direction) that it crosses the respective second section in said at least some of the layers, so that in each case a first partial section of the second section adjoins one of the two sides of the reinforcing element and a second partial section of the second section adjoins the other of the two sides of the reinforcing element, and wherein the print head in said at least one of the layers, after (in particular immediately after) the print head has been moved along the first partial section of the respective second section to the respective side of the reinforcing element (iethe side of the further reinforcing element to which the first sub-section is adjacent) and has dispensed building material in the process and / or before (in particular immediately before) the print head has been moved along the second sub-section of the respective second section away from the respective side of the reinforcing element (i.e. the side of the further reinforcing element to which the second sub-section is adjacent) and has dispensed building material in the process, presses building material through the at least one through-opening or through a further through-opening of the reinforcing element onto the respective other side of the reinforcing element.

[0042] In this embodiment, the building material applied in the aforementioned multiple layers along the respective first section of the printing web can form the first wall surface as a whole, and the building material applied in the aforementioned layers along the respective second section of the printing web can form the second wall surface as a whole. The building wall is thus (at least provisionally) designed to have at least a double wall. Depending on the distance between the two wall surfaces, a free space can be formed between the wall surfaces so that the building wall is hollow, whereby the free space can be filled after the wall surfaces have been erected, for example by at least partially pouring conventional concrete. In principle, the building wall can have further wall surfaces that can be designed in a corresponding manner.The first wall surface and the second wall surface may, in particular, be the two outermost wall surfaces, which thus define the building wall in opposite directions. However, this is not necessarily the case.

[0043] The respective first section and the respective second section preferably have the same length. The respective second section can, in particular, be offset parallel to the respective first section. If the two sections have a straight course, the direction of the parallel offset is preferably perpendicular to this course. If the sections have a curved course, the said parallel offset is preferably to be understood such that the respective first section and the respective second section run within the respective layer of the printing web in such a way that they are at a constant distance from one another.

[0044] The special feature of the present embodiment lies in particular in the fact that the at least one reinforcing element in the mentioned at least some of the multiple layers of the printing web, within which the building wall (to be erected) extends, not only crosses the respective first section provided for the first wall surface, but also the respective second section provided for the second wall surface. The reinforcing element therefore extends, in particular orthogonally to the two wall surfaces, from the first wall surface to the second wall surface. If the first wall surface and the second

[0045] Since the two wall surfaces are not directly adjacent to each other, the first wall surface and the second wall surface are connected by the reinforcement element across the distance between the two wall surfaces. This provides advantageous additional stabilization of the building wall.

[0046] The distance between the first wall surface and the second wall surface can be bridged, in particular, by the aforementioned web section of the reinforcement element. Any flange sections of the reinforcement element provided can be arranged within one or the other wall surface. Alternatively, at least one of the flange sections can be arranged on an outer side of each of the two wall surfaces, facing away from the other wall surface, and thus remains accessible from outside the building wall.

[0047] The invention is further explained below by way of example only with reference to the figures.

[0048] The Figures 1 and 2Each shows a highly simplified schematic representation of a building wall 11 being constructed using 3D printing. The building wall 11, which comprises a first wall surface 13 and can in principle also comprise additional wall surfaces, is still incomplete in each case.

[0049] A pressure head 15 is attached to the tool holder of a 3D positioning device (not shown in the figures), to which concrete is continuously fed as a building material 17, for example, from a concrete pump. This concrete is initially plastically deformable and can be dispensed from the pressure head 15 as a material strand at an outlet 19 of the pressure head 15. The concrete is a special concrete that is already largely dimensionally stable immediately after being dispensed from the pressure head 15 and then hardens rapidly.

[0050] The building wall 11 is 3D printed by applying the building material 17 along a predetermined printing path using the printing head 15, ie by moving the printing head 15 along the printing path using the 3D positioning device, thereby dispensing the building material 17. The printing path runs in several horizontal layers 21, of which Fig. 1 only one layer 21 is shown and in Fig. 2 only some layers 21 are shown. Starting from the lowest layer 21, which is located directly above the subsurface on which the building wall 11 is erected, the building material 17 is applied layer 21 by layer 21 according to the printing path.

[0051] In each of the multiple layers 21 within which the building wall 11 to be constructed extends, the print path comprises a respective first section 23, which in the example shown has a straight path. The building material 17 applied in the multiple layers 21 along the respective first section 23 then forms the first wall surface 13 as a whole. During the transition from a respective layer 21 to a subsequent layer 21, the print head 15 does not dispense any building material 17 in the example shown.

[0052] To stabilize the first wall surface 13, reinforcement elements 25 are fixed vertically aligned on the said substrate, each extending with an at least substantially constant cross-section along a longitudinal direction L. They extend through a number of layers 21 of the printing web corresponding to their respective length and thus cross the respective first section 23 in each of these layers 21 through which they extend. Each reinforcement element 25 thus divides the respective first section 23 in each of the said layers 21 into a first subsection and a second subsection.

[0053] Since two reinforcement elements 25 are provided in the examples shown, the respective first section 23 is not divided into just two, but into a total of three subsections 27, 29, 31. With respect to the left of the two reinforcement elements 25 shown in the figures, subsection 27 forms the first subsection and subsections 29, 31 form the second subsection, while with respect to the right-hand reinforcement element 25, subsections 27, 29 form the first subsection and subsection 31 forms the second subsection. In order to be able to clearly refer to subsections 27, 29, 31 in a simple manner, they are referred to below as first subsection 27, second subsection 29, and third subsection 31.

[0054] The first subsection 27 adjoins a first side 33 of the reinforcement element 25 shown on the left, and the second subsection 29 adjoins a second side 35 of the reinforcement element 25 shown on the left, opposite the first side 33. Similarly, the second subsection 29 adjoins a first side 33 of the reinforcement element 25 shown on the right, and the third subsection 31 adjoins a second side 35 of the reinforcement element 25 shown on the right, opposite the first side 33.

[0055] The reinforcement elements 25 each have a plurality of through-openings 37 that connect the first side 33 and the second side 35 of the respective reinforcement element 25. This allows the construction material 17 to be pressed through the through-openings 37 by the pressure head 15. Thus, it can be provided that the pressure head 15 is first moved along one of the partial sections 27, 29, 31 to the side 33, 35 of one of the reinforcement elements 25, to which the respective partial section 27, 29, 31 is adjacent, thereby applying the construction material 17 until the pressure head 15 has reached this side 33, 35 of the reinforcement element 25; and that the print head 15 subsequently continues to dispense the building material 17, but without being moved, so that the building material 17 is pressed through one or more through-openings 37 located in the respective layer 21 to the opposite side 33, 35 of the reinforcing element 25.The pressure head 15 can then be moved to this opposite side 33, 35 of the reinforcing element 25 and continue dispensing the building material 17 along the section 27, 29, 31 adjacent to this side 33, 35. Conversely, it can also be provided that the pressure head 15 is first moved, without dispensing any building material 17, to a side 33, 35 of one of the reinforcing elements 25 (for example, from the opposite side 33, 35 of the reinforcing element 25) and then dispenses the building material 17 there without being moved, so that the building material 17 is pressed through one or more through-openings 37 located in the respective layer 21 to the opposite side 33, 35 of the reinforcing element 25; and that the print head 15 subsequently applies the building material 17 along the section 27, 29, 31 adjacent to said side 33, 35.

[0056] For the described pressing process, it may be expedient if the outlet 19 of the pressure head 15 is designed such that the pressure head 15 can discharge the building material 17 with a directional component perpendicular to the sides 33, 35 of the respective reinforcing element 25. In the example shown, this is achieved by the outlet 19 being inclined. In addition, the pressure head 15 is mounted on the tool holder of the 3D positioning device so as to be rotatable about a vertical axis of rotation and can be rotated by the 3D positioning device about this axis of rotation, which in Fig. 1 by the additional representation of the print head 15 with a broken line. Such rotatability allows the print head 15 to dispense the building material 17 with pressure both against the first side 33 and (rotated by 180°) against the second side 35 of a respective reinforcing element 25, thereby pressing the building material 17 through respective through-openings 37.

[0057] In the examples shown, the reinforcement elements 25 are each designed as a profile that extends with an at least substantially constant cross-section along the longitudinal direction L of the respective reinforcement element 25. The cross-section in each case has a C-shape, the base of which corresponds to a web section 39 of the respective reinforcement element 25 and the legs of which correspond to flange sections 41 of the respective reinforcement element 25. The reinforcement elements 25 are each formed from a metal sheet strip that is bent at edges parallel to the longitudinal direction L in order to form the aforementioned C-shape. The flange sections 41 are thus aligned at least substantially orthogonally to the web section 39. Such profiles are known per se from drywall construction and lightweight steel construction and can advantageously be used in a new function as reinforcement in 3D printing.

[0058] The through-openings 37 are each formed in the web section 39. Many different shapes and sizes are possible for the through-openings 37. Preferably, the through-openings 37 are distributed according to a regular pattern over the entire length of the respective reinforcing element 25.

[0059] Depending on how and in what quantity the building material 17 is applied by the print head 15, the flange sections 41 can be surrounded by the building material 17, so that they (as in Fig. 1 shown) embedded in the building wall, or on its outer sides (as in Fig. 2 shown) remain free of building material 17 so that they are accessible even after the building wall 11 has been erected and are available, for example, for the attachment of other elements.

[0060] In particular, reinforcement elements 25, which are designed as profiles, can be applied to the Fig. 2shown to the respective substrate. A floor profile 43, which has a U-shaped cross-section, is fastened horizontally to the substrate so that the opening of the U-shape points upwards. The reinforcing elements 25 can then be inserted vertically from above into the floor profile 43 and, if necessary, fastened thereto. The dimensions of the floor profile 43 are preferably such that the reinforcing elements 25 inserted into the floor profile 43 are closely flanked laterally by the legs of the U-shape.

[0061] The maximum length of a respective reinforcement element 25 can be limited, in particular, by the distance of the outlet 19 of the print head 15 from the tool holder or from a cross member of the 3D positioning device, so that the mobility of the print head 15 is not hindered by the respective reinforcement element 25. In order to be able to erect building walls 11 in the manner described, the height of which is greater than the length of a respective reinforcement element 25, the reinforcement elements 25 can be extended. For this purpose, a further reinforcement element 45 can be attached to the end of a respective reinforcement element 25 pointing upwards in the fixed state, as an extension of this reinforcement element 25. Such further reinforcement elements 45 are shown in Fig. 2 shown (the right one is shown with a broken line). The other reinforcement elements 45 are each constructed identically to the respective reinforcement element 25 to which they are attached.

[0062] To fasten a respective further reinforcement element 45 to a respective reinforcement element 25, a profile connector 47 is used in each case, which also has a C-shape in cross-section, which at least substantially corresponds to the C shape of the respective reinforcement element 25 and the respective further reinforcement element 45, but is somewhat smaller, so that the profile connector 47 can be inserted along the longitudinal direction L with part of its longitudinal extent into the respective reinforcement element 25 and with the remaining part of its longitudinal extent into the respective further reinforcement element 45. In this way, the respective further reinforcement element 45 is fastened to the respective reinforcement element 25 in such a way that these two reinforcement elements 25, 45 are aligned with one another.

[0063] In order to further extend the reinforcement, additional reinforcement elements can be gradually attached to the additional reinforcement elements 45 during the 3D printing process until the reinforcement extends over the entire height of the building wall 11 to be erected.

[0064] As in Fig. 2 As shown, in addition to the vertically aligned reinforcement elements 25, one or more transverse reinforcement elements 49 can be integrated in a horizontal orientation into the first wall surface 13 of the building wall 11. For this purpose, a respective transverse reinforcement element 49 can be applied to the last applied building material 17 after the building material 17 has been applied in some of the layers 21 along the said first section 23 of the printing web. Fig. 2In the example shown, the transverse reinforcement element 49 is designed as a profile whose cross-section has a U-shape and is applied to the applied building material 17 with the opening of the U-shape facing downwards, so that the legs of the U-shape penetrate into the building material 17 or flank the building material 17 laterally. The transverse reinforcement elements 49 can, in particular, each extend over the entire distance between two reinforcement elements 25. In addition, they are each fastened to one or both of these reinforcement elements 25, although this is not absolutely necessary due to the embedding in the hardening building material 17.

[0065] Similar to the reinforcement elements 25, the transverse reinforcement elements 49 each have one or more through-openings 51, which, with respect to the cross-section of the transverse reinforcement elements 49, are provided at the bottom of the U-shape opposite the opening. Building material 17 can penetrate through the through-opening 59, so that building material 17, which is applied to a respective transverse reinforcement element 49 after it has been attached, can bond with the already applied building material 17 to which the respective transverse reinforcement element 49 was applied. As a result, the transverse reinforcement elements 49, like the reinforcement elements 25 or the further reinforcement elements 45, do not impair the formation of the building wall 11 as a cohesively continuous structure.Together, the reinforcement elements 25 and, if applicable, the further reinforcement elements 45 and the transverse reinforcement elements 49 contribute to an advantageous improvement in the stability of the building wall 11 in a simple manner that does not hinder 3D printing. Reference symbol

[0066] 11Building wall 13First wall surface 15Pressure head 17Building material 19Outlet 21Layer 23First section 25Reinforcement element 27Partial section 29Partial section 31Partial section 33First side 35Second side 37Through opening 39Web section 41Flange section 43Floor profile 45Further reinforcement element 47Profile connector 49Cross reinforcement element 51Through opening LLongitudinal direction

Claims

1. A method of erecting a building wall (11) in 3D printing, said method comprising - that a 3D positioning apparatus, in particular a gantry robot, having a tool holder, to which a printhead (15) is attached, is provided, - that an initially plastically deformable and then hardening building material (17), in particular a concrete, is fed to the printhead (15), and - that the building material (17) is applied by means of the printhead (15) along a predefined or predefinable printing path in that the printhead (15) is moved along the printing path by means of the 3D positioning apparatus and outputs the building material (17) in so doing, wherein the printing path extends in a plurality of horizontal layers (21), which are vertically offset in parallel with one another, and comprises a respective first section (23) in each of said layers (21) to form a first wall surface (13) of the building wall (11), wherein the method further comprises - that at least one elongate reinforcing element (25) is provided that extends along a longitudinal direction (L) and that has a first side (33) transverse to the longitudinal direction (L) and a second side (35) opposite to said first side (33) as well as at least one passage opening (37) which connects the two sides (33, 35) to one another, characterized in that - the at least one reinforcing element (25) is fixed vertically oriented on a substrate such that it crosses the respective first section (23) in at least some of the layers (21) so that in each case a first part section (27, 29) of the first section (23) adjoins one of the two mentioned sides (33, 35) of the reinforcing element (25) and a second part section (29, 31) of the first section (23) adjoins the other one of the two mentioned sides (33, 35) of the reinforcing element (25), and - in that the printhead (15), after it has been moved along the first part section (27, 29) towards the respective side (33, 35) of the reinforcing element (25) and has output building material (17) in so doing and / or before it has been moved along the second part section (29, 31) away from the respective side (33, 35) of the reinforcing element (25) and has output building material (17) in so doing, presses building material (17) in at least one of the layers (21) through the at least one passage opening (37) onto the respective other side (33, 35) of the reinforcing element (25).

2. A method according to claim 1, wherein the reinforcing element (25) is configured as a profile, in particular composed of plastic or preferably of metal, which extends along the longitudinal direction (L) with an at least substantially constant cross-section.

3. A method according to claim 1 or 2, wherein the reinforcing element (25) has a web section (39) which extends along the longitudinal direction (L) and which is oriented orthogonally to the first part section (27, 29) and / or to the second part section (29, 31), and wherein the at least one passage opening (37) is formed in the web section (39).

4. A method according to claim 3, wherein the reinforcing element (25) has one or more flange sections (41) which extend along the longitudinal direction (L) and which are oriented orthogonally to the web section (39).

5. A method according to claim 2, wherein the cross-section has a C shape, a U shape or an H shape having a web section (39) and two flange sections (41) oriented perpendicular thereto, and wherein the at least one passage opening (37) is formed in the web section (39).

6. A method according to claim 4 or 5, wherein the building material (17) is applied such that at least one of the flange sections (41) remains accessible from outside the building wall (11).

7. A method according to any one of the preceding claims, wherein the method further comprises - that a further elongate reinforcing element (45) is provided that extends along a longitudinal direction (L) and that has a first side (33) transverse to the longitudinal direction (L) and a second side (35) opposite to said first side (33) as well as at least one passage opening (37) which connects the two sides (33, 35) to one another, - that the further elongate reinforcing element (45), after the printhead (15) has applied building material in said at least some of the layers (21) along the respective first section (23), is fastened in extension of said reinforcing element (25) in a vertically oriented manner thereto such that said further elongate reinforcing element (45) crosses the respective first section (23) in at least some further ones of the layers (21) so that in each case a first part section (27, 29) of the first section (23) adjoins one of the two mentioned sides (33, 35) of the further reinforcing element (45) and a second part section (29, 31) of the first section (23) adjoins the other one of the two mentioned sides (33, 35) of the further reinforcing element (45), and - that the printhead (15), after it has been moved along the first part section (27, 29) towards the respective side (33, 35) of the further reinforcing element (45) and has output building material (17) in so doing and / or before it has been moved along the second part section (29, 31) away from the respective side (33, 35) of the further reinforcing element (25) and has output building material (17) in so doing, presses building material (17) in at least one of the layers (21) through the at least one passage opening (37) onto the respective other side (33, 35) of the further reinforcing element (45).

8. A method according to claim 7, wherein the further reinforcing element (45) is fastened to said reinforcing element (25) by means of a profile connector (47), which in turn has at least one passage opening (37), such that the at least one passage opening (37) of the profile connector overlaps with the at least one passage opening (37) of said reinforcing element (25) and / or with the at least one passage opening (37) of the further reinforcing element (45).

9. A method according to claim 7 or 8, wherein a plurality of reinforcing elements (25) of said kind are provided and a plurality of further reinforcing elements (45) of said kind are provided, and wherein the lengths of the plurality of reinforcing elements (25) differ so that the fastening of the plurality of further reinforcing elements (45) to a respective one of said plurality of reinforcing elements (25) takes place at different heights.

10. A method according to any one of the preceding claims, wherein the method further comprises - that an elongate transverse reinforcing element (49) is provided that extends along a longitudinal direction (L) and that has a first side (33) transverse to the longitudinal direction (L) and a second side (35) opposite to said first side (33) as well as at least one passage opening (37) which connects the two sides (33, 35) to one another, and - that the transverse reinforcing element (49), after the printhead (15) has applied building material (17) in at least one further one of the layers (21) along the respective first section (23), is applied horizontally oriented on the applied building material (17).

11. A method according to claim 10, wherein the transverse reinforcing element (49) applied to the applied building material (17) is coupled, in particular screwed, riveted or crimped, to said reinforcing element (25).

12. A method according to any one of the preceding claims, wherein the printing path comprises a respective second section in each of said layers (21) to form a second wall surface of the building wall (11), wherein the at least one reinforcing element (25) is fixed vertically oriented on a substrate such that it crosses the respective second section in said at least some of the layers (21) so that in each case a first part section of the second section adjoins one of the two mentioned sides (33, 35) of the reinforcing element (25) and a second part section of the second section adjoins the other one of the two mentioned sides (33, 35) of the reinforcing element (25), and wherein the printhead (15), after it has been moved along the first part section of the respective second section towards the respective side (33, 35) of the reinforcing element (25) and has output building material (17) in so doing and / or before it has been moved along the second part section of the respective second section away from the respective side (33, 35) of the reinforcing element (25) and has output building material (17) in so doing, presses building material (17) in said at least one of the layers (21) through the at least one passage opening (37) or a further passage opening (37) of the reinforcing element (25) onto the respective other side (33, 35) of the reinforcing element (25).