METHOD FOR PRODUCING A 3D-PRINTED PREFABRIC PART

Description

[0001] The invention relates to a method for producing a 3D-printed prefabricated part, preferably a prefabricated concrete element, for the construction industry, comprising the following method steps: in a first method step, at least one layer of at least one particulate aggregate is deposited on a production pallet by means of at least one layer depositing device, and in a second method step, a predetermined dose of at least one binder or at least one water-binder mixture is dispensed into at least one locally predetermined region of the at least one layer of the at least one aggregate by means of at least one print head.

[0002] Methods for producing 3D-printed prefabricated parts are known from the prior art. One method is known as Selective Cement Activation (SCA). In this process, a base material is mixed with a first binder component and applied in powder form. A second binder component is then applied in liquid form to the predetermined locations, whereby a reaction between the two binder components solidifies the base material. Another known process is known as Selective Paste Intrusion (SPI). In this process, a base material such as sand, brickwork, Liapor, or expanded clay is used, but is not mixed with a binder. Solidification in this case occurs through the application of a water-binder mixture.

[0003] The disadvantage of these processes is that the prefabricated parts produced with them have a low stability, which is at least sufficient in the construction industry.

[0004] Another known method from the state of the art is "contour crafting." There are approaches to increasing the stability of the components manufactured using this method by incorporating reinforcing cables. However, experimental studies based on pull-out tests and supplementary visual and microscopic observations have shown that chemical interactions between the mortar and the reinforcing cables impair the bond quality. Furthermore, the stability of components manufactured using contour crafting, which incorporate reinforcing cables, is generally lower than that of cast precast concrete elements. This is likely due to the lack of compaction and the flow of the mortar around the reinforcing cables, which creates voids beneath the cables. Furthermore, stability decreases with increasing length of the embedded reinforcing cables.

[0005] Further methods for producing 3D-printed finished parts are known from WO 2019 / 197088 A1, GB 2 509 757 A, and EP 3 335 857 A1. EP 3 335 857 A1 further discloses a method for producing a 3D-printed finished part according to the preamble of claim 1.

[0006] The object of the present invention is to at least partially remedy these disadvantages and to provide a method for producing a 3D-printed prefabricated part for the construction industry that is improved compared to the prior art, wherein the prefabricated parts produced by this method, in particular, exhibit sufficiently high stability. A system for carrying out such an improved method is also to be provided.

[0007] This problem is solved by the features of claim 1.

[0008] In the method according to the invention, it is therefore provided that in a third method step at least one reinforcement is arranged by means of at least one reinforcement placement device at least partially on and / or in at least the at least one locally predetermined area in which the predetermined dose of the at least one binder or of the at least one water-binder mixture was delivered in the course of the second method step, wherein the reinforcement is sunk at least partially in the locally predetermined area of ​​the at least one layer of the at least one particulate aggregate in which the predetermined dose of the at least one binder or of the at least one water-binder mixture was delivered in the course of the third method step, preferably by pressing, shaking and / or vibration.

[0009] Of course, reinforcements themselves are already known in the field of precast concrete element manufacturing. However, there was a misconception regarding the known printing processes that these printing processes were incompatible with such reinforcements.

[0010] The present invention radically breaks with this preconception. It was in no way foreseeable for a skilled person that it would be possible to integrate conventional reinforcement into the precast component during a printing process.

[0011] The precast elements produced by the inventive method not only exhibit significantly increased stability compared to those produced by conventional printing processes, but the inventive method also offers a number of advantages over manufacturing processes in which wet concrete is processed into precast concrete elements using formwork elements: Expensive and complex stations, such as formwork robots, and the associated formwork components and magnets can be eliminated. Flat elements, such as wall elements or ceiling elements, can be manufactured precisely and without formwork. Window recesses can be created without formwork. Any free-form shapes can be realized. Re-formwork work and the use of non-recyclable material can be completely eliminated. Openings and slots, printed "pipes" and printed "boxes" for electrical and plumbing equipment can be planned directly without additional effort and the use of plastics. Weight-reducing cavities can be printed directly. No additional compaction is necessary, as the particulate aggregate is applied in layers. A low water and cement factor is possible.which results in minimal cement consumption. Production can take place on a mobile production pallet. Alternatively or additionally, production is possible in which several production pallets are provided in series and the at least one print head and the at least one layer depositing device are moved across the production pallets. Production on a long track is just as possible, although in this case the at least one print head and the at least one layer depositing device are also moved across the production pallets. Production can be carried out within the framework of a carousel system, whereby drying racks, lifting stations with and without tilting devices, cleaning stations, oiling stations from the standard range of a carousel supplier and standard guidance and control systems of a carousel system can be used. The degree of automation can be further increased.from design to production the planning of a precast concrete element is easier, as a fully digitalized planning for a batch size of 1 is possible, complex work preparation is eliminated, less storage space is required for consumables,

[0012] As far as the reinforcement aspect is concerned, the method according to the invention is distinguished from manufacturing processes in which wet concrete is processed into precast concrete elements using formwork elements by the following advantages: no spacers are required for the plastic reinforcement protruding reinforcement is possible without any problems, whereas protruding reinforcement using formwork elements is only possible with a very high effort, if at all Lattice girders, connecting rods or other vertical reinforcement systems can be easily pressed in

[0013] The method according to the invention is, in principle, compatible with both an SCA and an SPI printing process. According to a preferred embodiment, an SPI printing process is used. This offers several advantages over an SCA printing process: the powder bed consists only of particulate aggregates, such as sand, brick chippings, Liapor, expanded clay, which have been known in the construction industry for decades different materials, such as insulation materials, can be used the base material is not mixed with a binder, which means that unbound material can be easily reused the water-binder mixture is applied selectively, not activated cement is used in the water-binder mixture, so residues can simply be broken up, sieved and used again the available print volume does not have to be filled optimally a complex unpacking station with extraction systems is not necessary, as dust development is significantly lower applying one or more first and last layers of the water-binder mixture opens up the possibility of smooth surfaces,which can otherwise only be realised by means of formwork or by screeding, but under no circumstances by means of an SCA printer. The particulate aggregates used are resistant to water. The manufactured components have a significantly higher strength. Portland cement can be used, so that valid approvals and standards can be used. The material costs are lower.

[0014] If an SPI pressure process is used, it is advisable that at least one water-binder mixture comprising water and at least one hydraulic binder, in particular a cementitious binder, is released during the second process step, and the dose of the at least one released water-binder mixture is large enough to achieve at least partial liquefaction in at least one spatially predetermined area of ​​the at least one layer of the at least one aggregate. This creates an ideal prerequisite for the reinforcement to be sunk at least partially into the spatially predetermined area of ​​the at least one layer during the subsequent third process step, preferably by pressing, shaking, and / or vibration.

[0015] Further advantageous embodiments of the method are defined in the dependent claims 2 to 12.

[0016] Further details and advantages of the invention are explained in more detail below with reference to the figures and the drawings, in which: Fig. 1 shows a first exemplary embodiment of a system for producing a precast concrete element in a schematic view, Fig. 2 shows a first exemplary embodiment of a 3D printing station in a schematic perspective view, Fig. 3a, and further exemplary embodiments of a 3D printing station in a schematic plan view, Fig. 4a, and further exemplary embodiments of a system for producing a precast concrete element in schematic views, Fig. 5 shows a schematic view of a further exemplary embodiment of a 3D printing station with the associated supply circuits, Fig. 6 shows a schematic view of a first exemplary embodiment of a pressure beam, Fig. 7a shows a schematic view of a first exemplary embodiment of a method for producing a 3D-printed precast element for the construction industry, Fig.8 shows a further exemplary embodiment of a printed precast concrete element in a schematically illustrated perspective view, Fig. 9a, b shows further exemplary embodiments of a printed precast concrete element in schematically illustrated perspective views, Fig. 10 shows a further exemplary embodiment of a printed precast concrete element in the form of a double wall in a schematically illustrated perspective view, Fig. 11 shows a further exemplary embodiment of a printed precast concrete element with an insulating layer in a schematically illustrated perspective view, Fig. 12 shows a further exemplary embodiment of a printed precast concrete element with printed recesses and concealed pipes for electrical cables in a schematically illustrated perspective view, Fig. 13a, b shows a first exemplary embodiment of a production pallet in a schematically illustrated top view, Fig.14a, b shows a further exemplary embodiment of a production pallet in a schematically illustrated plan view (partial figure a) and in a cross-sectional view from the side (partial figure b), Fig. 15 shows a further exemplary embodiment of a production pallet with two printed areas in a schematically illustrated plan view, Fig. 16 shows a further exemplary embodiment of a production pallet and a layer deposition device in a schematically illustrated cross-sectional view from the side, Fig. 17 shows a further schematically illustrated exemplary embodiment of a prefabricated concrete element in a perspective view, Fig. 18 shows an embodiment of a printing beam and a layer deposition device of a 3D printing station in a schematically illustrated cross-sectional view from the side, Fig. 19 shows a schematically illustrated exemplary embodiment of a printing head for the controlled dispensing of a water-binder mixture in a perspective view, Fig.20adas embodiment of the in . Fig. 19 shown print head, wherein a first part of a replaceable body was hidden, Fig. 20b the embodiment of the in Fig. 19 shown print head, wherein a first and a second partial body of an interchangeable body were hidden, Fig. 21a the embodiment of the in Fig. 19 shown print head in a perspective side view, Fig. 21b the embodiment of the in Fig. 21aillustrated print head, wherein a first and a second partial body of an interchangeable body have been hidden, Fig. 22a a schematically illustrated embodiment of an arrangement with a water-binder mixture, comprising water and at least one hydraulic binder, in particular a cementitious binder, and a print head for the controlled release of the water-binder mixture in a cross-sectional view along a cross-sectional plane parallel to a longitudinal axis of the print head, Fig. 22b the embodiment of the in Fig. 19 illustrated print head in a cross-sectional view along a cross-sectional plane perpendicular to a longitudinal axis of the print head, Fig. 23 a schematically illustrated embodiment of a valve of a print head for the controlled release of a water-binder mixture in a perspective view, Fig. 24a, b an isolated representation of a valve rod of the in Fig. 23shown valve and a nozzle body, wherein the valve rod and the nozzle body contact each other in the partial figure a and the valve rod and the nozzle body are spaced apart from each other in the partial figure b, Fig. 25 an isolated representation of a valve rod of the in Fig. 23 valve shown, and Fig. 26 an isolated representation of a nozzle body of the valve shown in Fig. 23 valve shown.

[0017] The Figure 1 shows a first embodiment of a system 53 for producing a, preferably flat, precast concrete element 54, comprising a plurality of stations through which at least one production pallet 32 ​​can pass, wherein the system 53 comprises at least one transport system with which the at least one production pallet 32 ​​can be transported through the system 53. The transport paths covered between the stations are indicated by arrows.

[0018] The system 53 further comprises at least one 3D printing station 29 with at least one layer deposition device 30 for the layer-by-layer deposition of at least one particulate aggregate 31 on the at least one production pallet 32 ​​and at least one print head 1 for the controlled dispensing of at least one water-binder mixture 2, comprising water and at least one hydraulic binder, in particular a cementitious binder, to at least one spatially predetermined area 33 of the production pallet 32 ​​and / or to a layer 34, 35, 36 of the at least one aggregate 31 deposited by the at least one layer deposition device 30 on the production pallet 32.

[0019] At least one storage device 56 is provided in which the at least one particulate additive 31 can be stored.

[0020] As from the Fig. 5As can be seen, at least one conveying device 57 can be provided, with which the at least one particulate additive 31 stored in the at least one storage device 56 can be conveyed to the at least one layer deposition device 30 of the at least one 3D printing station 29.

[0021] The system 53 further comprises at least one mixing device 58 with which the at least one water-binder mixture 2 can be provided.

[0022] As from the Fig. 5 As can be seen, at least one feeding device 59 can be provided, with which the at least one water-binder mixture 2 provided by the at least one mixing device 58 can be fed to the at least one print head 1 of the at least one 3D printing station 29.

[0023] The system 53 comprises at least one unpacking station 60, in which a precast concrete element 54 printed in the at least one 3D printing station 29 on the at least one production pallet 32 ​​can be unpacked from a non-bound particulate aggregate 31.

[0024] Finally, in the specifically illustrated embodiment, the system 53 comprises parking spaces 55 for at least one production pallet 32.

[0025] A key advantage of Plant 53 is that it eliminates the need for formwork and the associated formwork management systems, such as a formwork robot, a cleaning station, or a storage facility. It also eliminates the need for a concrete spreader and smoothing device, which are used in conventional carousel plants for the production of precast concrete elements.

[0026] By means of such a system 53, a method for producing a, preferably flat, prefabricated concrete element 54 can be carried out as follows: In the at least one 3D printing station 29, in a first printing process step, at least one layer 34, 35, 36 of the at least one particulate aggregate 31 is deposited on the production pallet 32 ​​by means of the at least one layer depositing device 30, and in a second printing process step, by means of the at least one print head 1, a predetermined dose 49 of the at least one water-binder mixture 2 is dispensed onto at least one locally predetermined area 33 of the at least one layer 34, 35, 36 of the at least one aggregate 31, preferably wherein the two printing process steps are repeated and / or carried out in reverse order.

[0027] It can be provided that at least one outer side of the precast concrete element 54 is provided with a predetermined surface structure during the printing process steps. This represents a significant advantage over conventional manufacturing processes, as expensive rubber matrices for shaping can be dispensed with. Instead, the predetermined surface structure, for example, a desired pattern, is printed.

[0028] The at least one particulate additive 31 is conveyed from the at least one storage device 56 by means of the at least one conveying device 57 to the at least one layer deposition device 30 of the at least one 3D printing station 29.

[0029] The at least one water-binder mixture 2 is provided in the at least one mixing device 58 and fed to the at least one print head 1 of the at least one 3D printing station 29 by means of the at least one feed device 59.

[0030] The at least one production pallet 32 ​​is transported by means of the at least one transport system from the at least one 3D printing station 29 to the at least one unpacking station 60, and a precast concrete element 54 printed in the at least one 3D printing station 29 on the at least one production pallet 32 ​​is unpacked from a non-bound particulate aggregate 31 in the at least one unpacking station 60.

[0031] If the system 53 has parking spaces 55 for the at least one production pallet 32, as in the case shown, the at least one production pallet 32 ​​is transported in a further method step by means of the at least one transport system from the at least one parking space 55 to the at least one 3D printing station 29.

[0032] The Figure 2 shows a first embodiment of a 3D printing station 29.

[0033] The 3D printing station 29 has at least two guide rails 92 on which the at least one layer deposition device 30 and / or the at least one print head 1 can be moved in a plane parallel to the at least one production pallet 32.

[0034] The 3D printing station 29 can comprise at least one height adjustment device with which a distance 93 of the at least one layer deposition device 30 or of a part of the at least one layer deposition device 30 and / or of the at least one print head 1 from a production pallet 32 ​​arranged in the at least one 3D printing station 29 can be changed in the vertical direction 37 depending on a printing progress.

[0035] The at least one print head 1 and the at least one layer deposition device 30 have a longitudinal extension in direction 41 and are movable in a direction 40 transverse thereto along the guide rails 92, which is indicated by a double arrow. The at least one print head 1 or components thereof and / or the at least one layer deposition device 30 or components thereof can also be movable in direction 41. More than one layer deposition device 30 and / or more than one print head 1 can also be provided. This allows the printing speed to be increased.

[0036] By means of the layer deposition device 30, layers 34, 35 of at least one particulate aggregate 31 can be deposited on the production pallet 32. With the aid of the pressure head 1, a predetermined dose of a binder or a water-binder mixture 2 comprising water and at least one hydraulic binder, in particular a cementitious binder, can be dispensed in a controlled manner to at least one spatially predetermined area 33 of the production pallet 32 ​​(in the event that no layer of the particulate aggregate 31 has yet been deposited on the production pallet 32) or to a layer 34, 35 of the at least one aggregate 31 deposited on the production pallet 32 ​​by the layer deposition device 30.

[0037] As in the case shown, the layer deposition device 30 can have a deposition hopper 66 as an intermediate storage for the at least one particulate aggregate 31.

[0038] The Figures 3a) and 3b) show two further embodiments of a 3D printing station 29 in a schematic plan view, wherein the two embodiments differ in that in the case of the Figure 3a ) several shorter production pallets 32 are used, which can be arranged in series one after the other in the printing station 29, and in the case of Figure 3b ) a long production pallet 32 ​​is used, on which several prefabricated components can be printed. The printing direction 38 is marked with an arrow.

[0039] The system 53 thus comprises at least one production pallet 32, which has a length 73 and the at least one 3D printing station 29 has a length 74, particularly preferably wherein the length 74 of the at least one 3D printing station 29 is at least twice as large as the length 73 of the at least one production pallet 32.

[0040] Compared to the example of the Figure 2the at least one 3D printing station 29 comprises at least one further layer deposition device 69 for the layer-by-layer deposition of at least one insulating material 70, preferably wherein the system 53 comprises at least one further storage device 71, in which the at least one insulating material 70 can be stored, and at least one further conveying device 72, with which the at least one insulating material 70 stored in the at least one further storage device 71 can be conveyed to the at least one further layer deposition device 30 of the at least one 3D printing station 29 (see also the Figure 5 ). In this context, it is advisable for the system 53 to also comprise at least one suction device for extracting unbound particulate aggregate 31.

[0041] The Figures 4a) and 4b) show two further embodiments of a system 53 for producing a precast concrete element. The systems 53 are designed as circulation systems in which one or more production pallets 32 circulate through the stations of the system 53 by means of a suitable transport system.

[0042] The systems 53 each have one or more storage locations 55. These can serve as intermediate storage for empty production pallets 32. From there, the production pallets 32 can be transported to one or more 3D printing stations 29. A central transfer platform 42 can be provided to manage multiple storage locations 55.

[0043] Optionally, at least one straightening machine 88, at least one reinforcement welding device 89 and / or at least one reinforcement placement device 90, with which at least one reinforcement 91 can be arranged on the at least one production pallet 32 ​​arranged in the at least one 3D printing station 29, can be provided.

[0044] The systems 53 each have at least one drying station 79 in which the at least one production pallet 32 ​​can be arranged in order to cure a precast concrete element 54 printed in the at least one 3D printing station 29 on the at least one production pallet 32. The at least one drying station 79 comprises at least one heating device 80 and at least one shelving system 81 in order to arrange at least two production pallets 32 one above the other in the at least one drying station 79. The drying station 79 is arranged downstream of the at least one 3D printing station 29 in the production direction.

[0045] A storage and retrieval machine 39 can be provided to operate the shelving system 81.

[0046] Following the drying station 79, the production pallets 32 can be transported to an unpacking station 60. This can include at least one tilting device 83 and / or at least one removal device 84 for removing the unbound particulate aggregate 31.

[0047] Finally, in the exemplary embodiments shown, the systems 53 each have at least one processing station 87 for processing the at least one production pallet 32, preferably wherein the at least one processing station 87 comprises at least one cleaning agent and / or release agent spraying device.

[0048] As in the first embodiment according to Figure 1 The 53 systems are designed without formwork robots.

[0049] The Figure 5shows a diagram of another embodiment of a 3D printing station 29 with the associated supply circuits.

[0050] The water-binder mixture 2 that can be delivered by the at least one pressure head 1 in this case comprises water and at least one cement-based binder. The associated system 53 comprises at least one cement storage device 61 in which cement can be stored and / or at least one bag discharge station 62 for cement bags. The at least one cement storage device 61 and / or the at least one bag discharge station 62 are in cement-conducting communication with the at least one mixing device 58, with which the at least one water-binder mixture 2 can be provided.

[0051] At least one flow agent can be fed in a metered manner to the mixing device 58 via a flow agent dispenser 99.

[0052] Following the mixing device 58, a compensation tank 98 can be arranged, from which, on the one hand, the water-binder mixture 2 can be fed to at least one print head 1 by means of a feed device 59, e.g., in the form of a pump, via a filter 97. On the other hand, any unused water-binder mixture 2 can be returned from the print head 1 to the compensation tank 98. It is important that the water-binder mixture 2 always remains in motion.

[0053] The layer deposition device 30 of the 3D printing station 29 is supplied with the particulate aggregate 31 to be applied from a storage device 56 by means of a conveying device 57, e.g., in the form of a pump. This aggregate 31 can be, for example, sand and / or expanded clay.

[0054] Optionally, the 3D printing station 29 can include a further layer deposition device 69, for example, for applying an insulating material 70. This can be supplied in a similar manner via a further storage device 71 and a further conveying device 72, for example, a pump.

[0055] The supply circuits of the two layer deposition devices 30 and 69 can be closed by the at least one unpacking station 60. This can have at least one separating device 86 for separating the at least one particulate aggregate 31 from at least one other material applied to the at least one production pallet 32 ​​by means of the at least one 3D printing station 29, preferably wherein the at least one separating device 86 comprises at least one sieve and / or at least one air classifier.

[0056] The materials separated in this way can then be returned to the storage devices 56 and 71, which may be, for example, a silo, by means of a return device 44 or 85 and a respective sieve 43. The return devices 44 or 85 may comprise, for example, a pump, a suction device, and / or a transport system.

[0057] The Figure 6 shows a diagram of a first embodiment of a printing beam 96. The printing beam 96 comprises several, e.g. five, printing heads 1, which can be supplied with the water-binder mixture 2 in parallel via lines 51.

[0058] The supply circuit comprises an expansion tank 98. A mixing propeller 100 can be arranged in this.

[0059] By means of a feed device 59, the water-binder mixture 2 can be conveyed into an intermediate tank 122. This can have a rinsing nozzle 104.

[0060] Furthermore, the intermediate tank 122 can be coupled to a quick-vent valve 103, with which the intermediate tank 122 can be vented in an emergency, e.g., due to a blockage. Reference numeral 101 denotes the nozzle pressure, and reference numeral 102 denotes the outlet of the quick-vent valve 103.

[0061] For pressure control, a pinch valve 108, a pressure regulator 107 and a level sensor 105 can be provided, which are connected or connectable to a control and / or regulating device 26.

[0062] The Figures 7a) to 7d ) show in four sub-steps a first embodiment of a method for producing a 3D-printed prefabricated part, preferably a prefabricated concrete element 54, for the construction industry.

[0063] The method comprises the following method steps: In a first method step, at least one layer 34, 35, 36 of at least one particulate aggregate 31 is deposited on a production pallet 32 ​​by means of at least one layer depositing device 30.

[0064] In a second method step, a predetermined dose 49 of at least one binder or at least one water-binder mixture 2 is delivered to at least one locally predetermined area 33 of the at least one layer 34, 35, 36 of the at least one additive 31 by means of at least one print head 1.

[0065] In a third method step, at least one reinforcement 91 is arranged by means of at least one reinforcement deposition device 90 at least in regions on and / or in at least the at least one locally predetermined region 33 at which the predetermined dose 49 of the at least one binder or of the at least one water-binder mixture 2 was delivered in the course of the second method step.

[0066] In the course of the third method step, at least one reinforcement 91 can be arranged in the form of a reinforcement mat, preferably made of steel and / or plastic, or in the form of fibers, preferably glass fibers.

[0067] The first and second process steps may be repeated at least once after the third process step, and / or the first and second process steps may be carried out in reverse order.

[0068] The at least one reinforcement 91 can have at least one recess 94 in at least one region of the at least one layer 34, 35, 36 of the at least one aggregate 31, in which the at least one binder or the at least one water-binder mixture 2 has not been released.

[0069] In the course of the third method step, the reinforcement 91 is sunk at least partially into the locally predetermined region 33 of the at least one layer 34, 35, 36 of the at least one particulate aggregate 31, in which the predetermined dose 49 of the at least one binder or of the at least one water-binder mixture 2 was delivered, preferably by pressing and / or vibration.

[0070] Reinforcement 91 can also be countersunk over several compression layers during the third process step. Reinforcement 91 does not need to be completely countersunk. A projection from the top, e.g., of 1-2 cm, is also possible.

[0071] The at least one reinforcement 91 can be arranged during the third method step such that the at least one reinforcement 91 has a lateral projection 95 beyond one side of the at least one layer 34, 35, 36 of the at least one particulate aggregate 31. Such projections, which serve in particular to connect the components to other components, can only be realized with enormous effort in conventional systems in which formwork is used.

[0072] After unpacking the manufactured precast element 54 from loose, unbound particulate aggregate 31, printed openings 111 remain, realized without formwork, e.g. as window recesses.

[0073] In the Figure 7b ) schematically shows a reinforcement placement device 90, with which the at least one reinforcement 91 can be arranged at least partially on and / or in at least the at least one spatially predetermined area 33 to which the predetermined dose 49 of the at least one binder or the at least one water-binder mixture 2 was dispensed during the second method step. The reinforcement placement device 90 can, for example, have two grippers 109, which are movably mounted along a support 110.

[0074] The Figure 8 shows a further embodiment of a printed precast concrete element 54, which in addition to an upper layer, which corresponds to the Figure 7d) shown precast concrete element 54, has a lower layer without reinforcement 91 and a layer of a co-printed insulating material 70 arranged therebetween.

[0075] The Figures 9a and 9b show further embodiments of a printed precast concrete element 54, in which reinforcements 91 are incorporated in the form of lifting anchors. These can be arranged protruding as shown or recessed in a printed pocket.

[0076] The Figure 10 shows another embodiment of a printed precast concrete element 54 in the form of a double wall. The double wall has two spaced-apart side elements 82 that are connected to each other via at least one reinforcement 91.

[0077] The two side elements 82 can either be printed separately on two production pallets 32 and then joined together or can be printed on one production pallet 32 ​​in the course of a single printing process.

[0078] The Figure 11 shows a further embodiment of a printed precast concrete element 54 with a layer of insulating material 70. In this case, it is a loose, ie unbound, insulating material.

[0079] The precast concrete element 54 can be produced in that, in a further process step, unbound particulate aggregate 31 is removed, preferably sucked off, in at least one region and, in a further process step, by means of at least one further layer laying device 30, at least one insulating material 70 is deposited in that region in which the unbound particulate aggregate 31 was removed.

[0080] The sides of the precast concrete element 54 can be closed by printed side walls or other measures so that the loose insulation material 70 cannot leak out of the precast concrete element 54.

[0081] The Figure 12 shows a further embodiment of a printed precast concrete element 54 with printed recesses 112 for flush-mounted boxes, recesses 113 for a roller blind control, recesses 114 for flush-mounted electrical cables and recesses 115 for switches.

[0082] The Figures 13a and 13b show a first embodiment of a production pallet 32, which includes a fixed side limit 117 and a, e.g., manual, side limit 75. In this way, a width 116 of the printable area can be changed. This can be useful, for example, if a smaller finished component is to be printed.

[0083] The Figures 14a and 14bshow a further embodiment of a production pallet 32, wherein the production pallet 32 ​​comprises two height-adjustable side limits 76, wherein the height-adjustable side limits 76 can each be brought into a first position on the production pallet 32, in which the side limits 76 laterally limit a volume that can be printed on the production pallet 32, and into at least one second position in which an upper side 77 of the side limits 76 is substantially aligned with an upper side 78 of the production pallet 32.

[0084] The Figure 15 shows another embodiment of a production pallet 32 ​​with two printed areas. Limits 118 are provided, which can be fixed, movable, or height-adjustable.

[0085] However, the lateral boundary of a pressed prefabricated element does not necessarily have to be formed by boundaries in the form of separate boundary elements. A lateral boundary can also be formed during a compression process in the form of cones of material 119 made of the at least one particulate aggregate 31.

[0086] The Figure 16 shows a further embodiment of a production pallet 32 ​​and a layer depositing device 30 in a schematically illustrated cross-sectional view from the side.

[0087] To produce the smoothest possible side surface 123 of a prefabricated component to be printed, the nozzle distance of a print head 1 from a lateral boundary can be selected as small as possible. Ideally, a side surface 123 that is virtually formwork-smooth can be produced in this way.

[0088] It is advisable for the layer deposition device 30, as in the illustrated case, to have a plurality of segments 63 that can be individually activated and deactivated in order to achieve a predetermined, i.e., variably adjustable, layer deposition width 64. In this context, it is advisable for the layer deposition device 30 to have inner and / or outer bulkheads.

[0089] In an analogous manner, it can be provided that the printing bar is designed in several parts and has print heads 1 that can be activated and deactivated individually in order to achieve a predetermined printing width.

[0090] The Figure 17shows a further embodiment of a precast concrete element 54, manufactured according to a previously described method. Layers 34, 35, 36 of the at least one particulate aggregate 31 are deposited on the production pallet 32 ​​by means of the at least one layer depositing device 30. The layers 34, 35, 36 are indicated by dashed lines. A predetermined dose 49 of the water-binder mixture 2 is dispensed into spatially predetermined areas 33 of the layers 34, 35, 36 of the at least one aggregate 31 by means of the pressure head 1.

[0091] In the illustrated precast concrete element 54, before a first layer 34 of the at least one aggregate 31 is deposited on the production pallet 32, a predetermined dose 49 of the at least one water-binder mixture 2 is dispensed at least one spatially predetermined area 33 of the pressure platform 32, and after a final layer 36 of the at least one aggregate 31 is deposited, a predetermined dose 49 of the water-binder mixture 2 is dispensed at least one spatially predetermined area 33 of the final layer 36 of the at least one aggregate 31. In this way, very smooth surfaces 48 can be produced on the top and bottom sides of the precast concrete element 54, which are similarly smooth to the surfaces that can be produced conventionally using formwork.

[0092] The Figure 18shows an embodiment of a printing beam 30 and a layer deposition device 30 of a 3D printing station in a schematically illustrated cross-sectional view from the side.

[0093] The layer deposition device 30 comprises a metering roller 65, via which the at least one particulate aggregate 31 can be applied to the at least one production pallet 32.

[0094] A removal device 120, e.g. in the form of a brush, is provided, with which the at least one particulate additive 31 can be removed in a metered manner from the metering roller 65.

[0095] The metering roller 65 can also be designed in several parts.

[0096] A deposition hopper 66 is provided which can be set into vibration by at least one vibration device so that tilting of large-grained material can be prevented.

[0097] The layer deposition device 30 comprises at least one discharge opening 67 and at least one metering flap 68, with which the at least one discharge opening 67 can be closed to different extents, so that a discharge quantity of the at least one particulate additive 31 can be metered.

[0098] The direction of movement of the pressure beam 30 and the layer deposition device 30 is indicated by the reference numeral 121.

[0099] The pressure bale 30 and the layer depositing device 30 or at least a part of the layer depositing device 30 can be raised and lowered individually and independently of one another.

[0100] The Figure 19and the following figures show a schematically illustrated embodiment of a print head 1 for the controlled dispensing of a water-binder mixture 2, comprising water and at least one hydraulic binder, in particular a cementitious binder, wherein the print head 1 comprises a feed channel 3 for supplying the water-binder mixture 2, a plurality of outlet openings 4 which can be brought into fluid connection with the feed channel 3, and a plurality of valves 5 with which the outlet openings 4 can be opened and closed in a controlled manner, whereby a predetermined dose 49 of the water-binder mixture 2 can be dispensed through the outlet openings 4.

[0101] The outlet openings 4 are arranged equidistantly on a line 27.

[0102] The valves 5 are designed as electropneumatic valves and each have a compressed air connection 11 and an electrical connection 12. Via the compressed air connection 11, the valve 5 can be supplied with compressed air, with which a cylinder 47, which is connected to a valve rod 14 in a motion-coupled manner, can be actuated. See also Figure 22b .

[0103] The valves 5 each have a valve rod 14, preferably made of at least one hard metal, which is adjustable over an adjustment path 13 between 0.5 and 1.5 mm. The adjustment path 13 is in the Figure 24b shown.

[0104] As in the case shown, the valve rods 14 can have a free end 15 which is spherical head-shaped.

[0105] The valves 5 may comprise at least one return spring 16, preferably wherein the at least one return spring 16 is designed such that the associated outlet opening 4 can be closed with a closing force between 10 and 50 N, particularly preferably with a closing force between 20 and 40 N. In the Figure 22b Such a return spring is shown schematically.

[0106] The valves 5 can have a bearing 46 for the valve rod 14, wherein the bearing 46 can be sleeve-shaped, as in the illustrated case. The bearing 46 surrounds the valve rod 14, and the valve rod 14 moves relative to the bearing 46.

[0107] For each valve 5, a preferably replaceable sealing membrane 17 is provided, which seals the valve rod 14 against penetration of the water-binder mixture 2.

[0108] In this specific case, the sealing membrane is arranged sealingly between the valve rod 14 and the bearing 46.

[0109] The print head 1 has several venting channels 25, with which a pressure equalization for the valve rods 14 can be generated. See also Figure 22b . Without the venting channels 25, there is a risk that a negative pressure will develop on the side of the sealing membrane 17 facing the valve 5, through which a part of the water-binder mixture 2 will be sucked in and thereby penetrate into the valve 5.

[0110] Based on the Figures 20a and 20b It is particularly clearly visible that the print head 1 comprises a base body 6, on which the valves 5 are arranged, and an interchangeable body 7 which is detachably connectable to the base body 6, wherein the outlet openings 4 and the supply channel 3 are arranged on the interchangeable body 7. Fastening means 45 can be provided for the detachable connection of the interchangeable body 7 to the base body 6 (see Figure 19), which, as in the case shown, can be designed as screws that engage in threads formed in the base body 6.

[0111] The interchangeable body 7 consists of at least one acid-resistant plastic, preferably selected from a group consisting of PE, PVC, POM, PTFE and mixtures thereof and comprises at least one injection-molded part.

[0112] The exchangeable body 7 has two detachably connectable partial bodies 8, 9, preferably with a seal 10 arranged between the two partial bodies 8, 9 (compare the Figures 20a and 22b ).

[0113] The Figure 22ashows a schematically illustrated embodiment of an arrangement 28 with a water-binder mixture 2, comprising water and at least one hydraulic binder, in particular a cementitious binder, and a print head 1 for the controlled release of the water-binder mixture in a cross-sectional view along a cross-sectional plane parallel to a longitudinal axis 50 of the print head 1. The longitudinal axis 50 is exemplary in the Figure 2 marked.

[0114] The print head 1 is designed according to the preferred embodiment described above.

[0115] The at least one hydraulic binder is selected from a group consisting of Portland cement, calcium aluminate cement, calcium sulfoaluminate cement and mixtures thereof.

[0116] The water-binder mixture 2 comprises an additive in the form of a flow agent.

[0117] The feed channel 3 has an inlet opening 21 for the water-binder mixture 2, wherein the feed channel 3 has an outlet opening 22 opposite the inlet opening 21. The inlet opening 21 and the outlet opening 22 each have a thread 23 for connecting a fluid line 24.

[0118] The water-binder mixture 2 can be arranged in an intermediate tank 122. The fluid lines 24 connect the intermediate tank 122 to the feed channel 3 of the print head. 1.

[0119] A control and / or regulating device 26 is provided, with which the valves 5 of the print head 1 can be controlled. The control and / or regulating device 26 is connected to the electrical connection 12 of the valves 5 via lines 52.

[0120] By means of the arrangement 28, a method for the controlled dispensing of a water-binder mixture 2, comprising water and at least one hydraulic binder, in particular a cementitious binder, can be carried out, wherein the method comprises the following method steps: the water-binder mixture 2 is supplied via the supply channel 3 of the print head 1 to the outlet openings 4 of the print head 1, preferably at a pressure between 0.1 and 2.0 bar, and the outlet openings 4 are opened and closed in a controlled manner by means of the valves 5 of the print head 1 and thereby a predetermined dose 49 of the water-binder mixture 2 is dispensed through the outlet openings 4.

[0121] The Figures 23, 24a, 24b, 25 and 26show details of an embodiment of a valve 5 of the print head 1 for the controlled release of a water-binder mixture 2, as well as a nozzle body 18 cooperating with the valve rod 14 of the valve 5, in which the outlet opening 4 is formed. The diameter 20 compare Figure 22a the outlet opening 4 is between 0.5 and 2.0 mm.

[0122] The nozzle body 18 is formed from at least one hard metal or ceramic and has an inclined contact surface 19 for a free end 15 of the valve rod 14 of the valve 5. The inclined contact surface 19 can be funnel-shaped, as in the illustrated case.

Claims

1. Method for producing a prefabricated 3D-printed part, preferably a concrete prefabricated component (54), for the construction industry, comprising the following method steps: - in a first method step at least one layer (34, 35, 36) of at least one particulate aggregate (31) is deposited on a production pallet (32) by means of at least one layer depositing device (30), - in a second method step a predetermined dose (49) of at least one binder or at least one water-binder mixture (2), comprising water and at least one hydraulic binder, in particular a cement-based binder, is delivered at at least one locally predetermined region (33) of the at least one layer (34, 35, 36) of the at least one aggregate (31) by means of at least one printhead (1), - in a third method step at least one reinforcement (91) is arranged, by means of at least one reinforcement depositing device (90), at least in regions on and / or in at least the at least one locally predetermined region (33), at which the predetermined dose (49) of the at least one binder or the at least one water-binder mixture (2) was delivered in the course of the second method step, characterized in that the reinforcement (91) is sunk, in the course of the third method step, at least in regions into the locally predetermined region (33) of the at least one layer (34, 35, 36) of the at least one particulate aggregate (31) in which the predetermined dose (49) of the at least one binder or of the at least one water-binder mixture (2) has been delivered, preferably by pressing, shaking and / or vibration.

2. Method according to claim 1, wherein in the course of the third method step at least one reinforcement (91) is arranged in the form of a reinforcement mesh, preferably wherein - the reinforcement mesh is manufactured from steel and / or plastic, and / or - the reinforcement mesh is welded together from individual rods and / or at least one lattice girder, and / or - comprises fiber rods.

3. Method according to claim 1 or 2, wherein in the course of the third method step at least one reinforcement (91) is arranged in the form of fibers, preferably glass fibers.

4. Method according to one of claims 1 to 3, wherein in the course of the third method step at least one reinforcement (91) is arranged in the form of at least one individual rod, preferably provided by means of at least one straightening machine (88).

5. Method according to one of claims 1 to 4, wherein the at least one reinforcement (91) is produced in a further method step, which is effected before the third method step, in at least one reinforcement welding device (89), which is preferably formed as a mesh welding system and / or as a lattice girder welding system, preferably wherein the production is effected when needed and / or CAD-controlled and / or with a batch size of 1.

6. Method according to one of claims 1 to 5, wherein the first and second method steps are repeated at least once after the third method step, and / or the first and second method steps are carried out in reverse order.

7. Method according to one of claims 1 to 6, wherein in the course of the second method step at least one water-binder mixture (2), comprising water and at least one hydraulic binder, in particular a cement-based binder, is delivered, and wherein the dose of the at least one water-binder mixture (2) delivered is large enough that a liquefaction at least in regions is achieved at the at least one locally predetermined region (33) of the at least one layer (34, 35, 36) of the at least one aggregate (31).

8. Method according to one of claims 1 to 7, wherein in the course of the third method step the at least one reinforcement (91) is arranged such that the at least one reinforcement (91) has a lateral protrusion (95) beyond a side of the at least one layer (34, 35, 36) of the at least one particulate aggregate (31).

9. Method according to one of claims 1 to 8, wherein in a further method step unbound particulate aggregate (31) is removed, preferably extracted, at least in one region.

10. Method according to claim 9, wherein in a further method step at least one insulation material (70) is deposited by means of at least one further layer depositing device (30) in the region in which the unbound particulate aggregate (31) was removed.

11. Method according to one of claims 1 to 10, wherein - a predetermined dose (49) of the at least one water-binder mixture (2) is delivered at at least one locally predetermined region (33) of the printing platform (32) before a first layer (34) of the at least one aggregate (31) has been deposited on the production pallet (32), and / or - a predetermined dose (49) of the water-binder mixture (2) is delivered at at least one locally predetermined region (33) of the last layer (36) of the at least one aggregate (31) after a last layer (36) of the at least one aggregate (31) has been deposited.

12. Method according to one of claims 1 to 11, wherein prefabricated parts in the form of wall elements for buildings are produced by means of the method.