Equipment for additive manufacturing of structures

Abstract

The present invention relates to an apparatus for additive manufacturing of structures, preferably architectural structures, comprising: a nozzle having a structural material outlet configured to extrude a structural material in forming a hollow core bead along a manufacturing path defined by a plurality of points, a fluid outlet configured to inject a fluid into the hollow core of the extruded bead, a fluid pressure regulating device configured to regulate the pressure of the fluid injected into the hollow core of the extruded bead via the fluid outlet, and a control unit configured to determine pressure values ​​assigned to the points of the manufacturing path and to control the fluid pressure regulating device based on the determined pressure values. Furthermore, the present invention relates to a method for generating control data for such an apparatus.

Description

[Technical Field]

[0001] The present invention relates to an apparatus, assembly and system for additive manufacturing of structures, preferably architectural structures. Furthermore, the present invention relates to a method for generating control data for such an apparatus, assembly or system. [Background technology]

[0002] In a typical additive manufacturing process, three-dimensional physical objects are fabricated from three-dimensional digital models. These three-dimensional digital models are typically divided into a stack of flat layers by so-called slicing software, with each layer describing a linear manufacturing path for the additive manufacturing system. The additive manufacturing system builds up structural material along the manufacturing path of the first layer before proceeding to the adjacent layer, and so on. The structural material from the manufacturing paths of successive layers is aggregated to create a complete three-dimensional physical version of the digital model.

[0003] Recently, additive manufacturing (AM) technology has been established in the fields of architecture, engineering, and construction. This field requires large-scale components on a building scale. In particular, polymer extrusion systems have been scaled up to AM architectural structures. These include fused filament manufacturing (FFM) systems and fused particle manufacturing (FPM) systems, which differ in the form of their feedstock. FFM materials are provided in the form of continuous filaments of thermoplastic material, for example, from large spools, while FPM materials are provided in the form of thermoplastic particles. In both cases, the thermoplastic feedstock is provided to an extrusion mechanism that includes a screw for conveying the material, a heating device for melting the feedstock, and a nozzle with an orifice through which the molten feedstock is extruded to produce beads along the manufacturing path of each slice. These beads are then stacked on top of each other by the AM system to produce a three-dimensional object.

[0004] The production of architectural structures requires large-dimensional beads, high-power heating to melt the raw materials, and high-power cooling to solidify the extruded beads to achieve high build-up rates. These requirements make such processes economically unviable and environmentally unsuitable. To address these drawbacks, U.S. Patent Application Publication No. 2016 / 0096320 teaches the extrusion of hollow-core beads, which significantly reduces both the heating and cooling energy required to produce architectural structures in an additive manner. Such hollow-core beads also harden significantly faster due to their larger surface area. However, additive manufacturing techniques for architectural structures with hollow-core beads known from the prior art exhibit the drawback of being unable to guarantee a consistent high manufacturing quality. Summary of the Invention

[0005] The present invention addresses these shortcomings of the prior art by providing an apparatus for additive manufacturing of structures, preferably architectural structures, comprising a nozzle, a fluid outlet, a fluid pressure regulating device, and a control unit. The different components of the apparatus can all be in direct or indirect contact with each other, although some or all of these components can also be provided in a dispersed, non-contact manner. The structure can be a component for the architecture, engineering, and building fields. The architectural structure can be a formwork for concrete, an architectural interior component, a facade element, furniture such as a chair, and / or another architectural component. Furthermore, the structure can be a component for aircraft, ships, automobiles, or other industries. The structure can be a prototype and / or component used to manufacture prototypes for any application. It can also be a component for the advertising industry, such as an illuminated advertising component. The component can be a mold used in large-scale fixtures and / or tools, carbon fiber composites, concrete casting, and / or other manufacturing processes. The structure can have dimensions greater than 1 m, preferably greater than 2 m, and optionally greater than 5 m.

[0006] The nozzle of the apparatus of the present invention comprises a structural material outlet configured to extrude a structural material in the form of a hollow core bead along a manufacturing path. The manufacturing path may be defined by a plurality of points and may correspond to the manufacturing paths described above in connection with the prior art. The manufacturing path may be a path of a slice of a three-dimensional digital model of a structure. The slice may be a planar or non-planar slice. Alternatively or additionally, the manufacturing path may be freely defined, for example, using a set of points and / or curves in three-dimensional space, optionally without being based on a three-dimensional digital model of the structure to be manufactured. These points and / or curves may, but need not, be in the same plane. The nozzle may be a single, integrally formed component or a component formed by the assembly of two or more parts. Preferably, the nozzle is integrally formed by additive manufacturing, for example, from a metal, preferably aluminum or copper. The structural material may be a polymer, preferably a thermoplastic, but may also be a different material. The structural material outlet may comprise a single orifice, preferably in the form of a circular or rectangular ring, but may also comprise multiple orifices, which may be separated from each other by structural portions of the nozzle. When the structural material outlet is formed as a circular ring, the nozzle may include a rod-shaped element, e.g., a barb, disposed coaxially at the center of the circular ring orifice, the rod-shaped element being configured to divide the molten structural material into a thin wall and a hollow core.

[0007] The nozzle may have a mounting interface for mounting the nozzle to the extruder. The mounting interface may be formed as a thread, e.g., a male thread, that is provided in threaded engagement with a thread, e.g., a female thread, of the extruder. Alternatively or additionally, the nozzle may be mounted to the extruder via a non-rotational connection system that does not have a thread. The nozzle may also be integrally formed with the extruder. In addition, the nozzle may have a construction material inlet that can provide molten construction material from the extruder to the nozzle. The nozzle may exhibit an elongated, preferably cylindrical, form. The inlet and outlet for the construction material may be provided on opposite faces of the elongated nozzle.

[0008] The fluid outlet configured to inject a fluid into the hollow core of the bead extruded through the structural material outlet of the nozzle can have a single orifice or multiple orifices. If the fluid outlet has multiple orifices, they may be adjacent to each other, or some or all of the orifices may be separated and located apart from each other. The fluid outlet may be integrated into the nozzle or located separately from the nozzle. In the latter case, the fluid outlet may be attached to the nozzle or located apart from the nozzle without any physical contact between the two components. However, the fluid outlet is configured to be positioned relative to the nozzle so that the fluid can be injected into the hollow core of the beam extruded from the structural material outlet. The fluid may be a liquid and / or a gas, preferably air. The fluid may also be a foam or any other functional material.

[0009] The fluid pressure regulating device is configured to regulate the pressure of the fluid injected into the hollow core of the extruded bead through the fluid outlet. The pressure regulation may be an adaptation of the non-atmospheric pressure to a different non-atmospheric pressure. In other words, when the non-atmospheric pressure is adjusted, it may be an increase or decrease to a different non-atmospheric pressure value. In alternative embodiments, the pressure control may also be switched on or off. The fluid pressure regulating device may be integrated into the pressure source and / or may be provided separately from the pressure source. The fluid pressure regulating device may directly or indirectly control the pressure of the fluid by controlling another parameter of the fluid, e.g., temperature, which exhibits a predetermined correlation with the fluid pressure. The fluid pressure regulating device may be located upstream and / or downstream of the fluid outlet of the apparatus.

[0010] The apparatus further includes a control unit configured to determine pressure values ​​assigned to points in the manufacturing path and to control the fluid pressure regulating device based on the determined pressure values. In one embodiment, the control unit includes a memory, e.g., a non-volatile memory, that stores data describing a manufacturing path of a slice of the three-dimensional digital model by a plurality of points. The points may be stored in any coordinate system, e.g., a Cartesian or polar coordinate system. Some or all of these points describing the manufacturing path may have a pressure value assigned to that particular point. The pressure values ​​assigned to different points in the manufacturing path may be different from each other and may be greater than atmospheric pressure. They may also be less than or equal to atmospheric pressure. The pressure values ​​may be absolute or differential values ​​describing a pressure difference relative to another pressure value. The data may be stored as a lookup table in the memory.

[0011] The control unit may be configured to determine the next position in the manufacturing path stored in the data and the pressure value assigned to that position in the data. Once the respective pressure value is determined by the control unit, it may be configured to control the pressure regulating device based on the determined value. In one embodiment, the control unit may be configured to control the fluid pressure regulating device such that the pressure of the fluid injected into the hollow core of the extruded bead corresponds to the determined pressure value. The different pressure values ​​assigned to different positions in the manufacturing path may be predetermined and loaded into the memory of the control unit before starting the actual additive manufacturing process of the structure. Additionally or alternatively, data assigning different pressure values ​​to different points in the manufacturing path may be provided to the control unit during the manufacturing process.

[0012] The idea underlying the present invention is that the manufacturing quality of extruded hollow core beads depends on the pressure of the fluid injected into the bead. In particular, depending on the geometric shape of the manufacturing path, the pressure of the fluid injected into the hollow core bead through the fluid outlet should be adjusted to obtain a structure with optimal quality. By having a control unit configured to determine pressure values ​​to be assigned to points in the manufacturing path and to control the fluid pressure regulating device based on the determined pressure values, the apparatus for additive manufacturing of structures of the present invention can take into account the geometric shape of the manufacturing path and adjust the pressure values ​​at different points depending on the geometric shape of the manufacturing path. Thus, the apparatus of the present invention enables the additive manufacturing of architectural structures with hollow core beads having the advantages outlined above with respect to the prior art, while at the same time enabling excellent manufacturing quality even in the case of complex shapes. Furthermore, according to the present invention, the bead diameter can be easily varied along the manufacturing path by adjusting the pressure value. Hollow core beads manufactured using the device of the present invention exhibit increased strength and very good thermal properties, which make them very attractive for architectural applications.

[0013] According to one embodiment, the apparatus further includes a sensing device for determining at least one of geometric parameters of the extruded bead and parameters of the fluid within the hollow core of the extruded bead. The sensing device may include one or more sensors. The sensing device may be integrated into or attached to the nozzle and / or provided separately from the nozzle. According to this embodiment, the control unit is configured to control the fluid pressure regulating device based on the determined parameters. This embodiment enables analysis of the quality of the extruded bead during production, for example, by comparing the value determined by the sensing device with a desired value. If there is a deviation exceeding a threshold, the control unit may control the fluid pressure regulating device to adjust the pressure of the fluid injected into the hollow core of the extruded bead to counteract such deviation. Alternatively or additionally, if there is a deviation exceeding a threshold, the control unit may be configured to adjust the operation of the extruder, for example, the extruder's material output rate and / or the speed of a movement mechanism for moving the nozzle along the production path. The threshold may be predetermined and stored in the memory of the control unit. Thus, this embodiment enables the production of structures with hollow core beads of superior quality. The sensing device may be configured to continuously monitor a parameter of the bead. In alternative embodiments, the sensing device may be configured to monitor a parameter at a predetermined location and / or time.

[0014] The geometric parameters of the extruded bead may be at least one of the wall thickness and extrusion height of the extruded bead. The wall thickness of the extruded bead may correspond to the wall thickness ranging from the outer periphery of the bead to the internal void of the bead. If the hollow core bead has the shape of a hollow cylinder, the wall thickness corresponds to the radial extension of a ring surrounding the cylindrical internal void. The wall thickness may be determined at a single or multiple locations of the extruded bead. The extrusion height may correspond to the overall height of the extruded bead, for example, in the direction of gravity. For example, if the extruded bead collapses under its own weight, this results in a decrease in the extrusion height, which may be detected by a detection device. The control unit may then increase the pressure of the fluid injected into the hollow core of the extruded bead via the fluid pressure regulating device in response to the detection. Similarly, if the detected wall thickness of the extruded bead is smaller than a desired value, the control unit may be configured to decrease the pressure of the fluid injected into the hollow core of the extruded bead via the fluid pressure regulating device to counteract over-expansion of the extruded bead, which typically involves a decrease in wall thickness. In alternative embodiments, the sensing device is configured to determine a geometric parameter other than the wall thickness and the extrusion height. Additionally or alternatively, the sensing device may be configured to determine a parameter of the fluid within the hollow core of the extrusion bead, such as fluid pressure and / or temperature. The control unit may be configured to compare the determined geometric and / or fluid parameter with a predetermined value, which may be stored in the memory of the control unit, and adjust the pressure of the fluid pressure regulating device if the determined value exceeds such predetermined value. Alternatively or additionally, the control unit may be configured to adjust the material extruded by the extruder and / or the speed of a movement mechanism for moving the nozzle along the production path as described above.

[0015] According to one embodiment, the fluid pressure regulating device comprises an adjustable flow control valve for regulating the pressure of the fluid injected into the hollow core of the extruded bead. The adjustable flow control valve may be an electronic pressure valve. The flow control valve may be provided in a fluid line between a fluid source and a fluid outlet. Additionally or alternatively, the fluid pressure regulating device may comprise a fluid source for regulating the pressure of the fluid injected into the hollow core of the extruded bead and / or other devices for regulating the fluid pressure of the fluid, including, for example, a pump.

[0016] According to one embodiment, the apparatus further includes a pressure relief valve for relieving excess pressure present within the hollow core of the extrusion bead. The pressure relief valve may be in direct fluid communication with the fluid outlet, e.g., it may be provided in the fluid path between the fluid source and the fluid outlet. The pressure relief valve may be in fluid communication with the fluid outlet only through the hollow core of the extrusion bead. The pressure relief valve may be spring-activated. It has been found that, particularly in large-scale applications for manufacturing architectural structures, printing defects and / or specific geometric shapes, such as corners of the manufacturing path, can result in increased pressure in the hollow core of the extrusion bead, which can lead to over-expansion and therefore a larger-than-expected diameter. The provision of a pressure relief valve according to this embodiment relieves such excess pressure, enabling improved manufacturing quality of the manufactured structures.

[0017] According to one embodiment, the pressure relief valve is adjustable and is part of the fluid pressure regulating device. In this embodiment, the control unit is configured to adjust the adjustable pressure relief valve based on a pressure value determined by the control unit. In other words, in this embodiment, the overpressure at which the pressure relief valve is activated is adjustable by the control unit of the present invention. This embodiment has the advantage that the overpressure at which the pressure relief valve is activated can be adjusted depending on the geometry of the production path. At the same time, in one embodiment, the control unit may be configured to adjust the overpressure at which the pressure relief valve is activated based on parameters determined by the above-mentioned sensing device. Therefore, this embodiment provides an apparatus with a fluid pressure regulating device that is low in complexity and highly reliable.

[0018] According to one embodiment, the nozzle's structural material outlet is configured to extrude hollow core beads having at least one cross-sectional shape of a hollow polygon, preferably a hollow rectangle, e.g., a hollow square, a hollow oval, preferably a hollow circle, and a solid polygon or solid oval containing one or more polygonal or oval voids. The hollow polygon and hollow oval may have one or more internal cross-reinforcing struts, but may also be completely hollow without any internal struts or other forms of reinforcement. To be able to extrude beads having such cross-sectional shapes, the nozzle includes respective orifices or structures having respective orifices that form corresponding dies. Each structure may be integrally formed with the rest of the nozzle. Alternatively, each structure may be embodied by a separate part that can be attached to the nozzle and detached to be replaced by another part having a different structural configuration in order to extrude beads having different cross-sectional shapes. In addition to the shapes described above, the nozzle may be configured to extrude different shapes or combinations of these shapes, as long as the extruded bead has a hollow core.

[0019] According to one embodiment, the nozzle comprises a fluid outlet, the fluid outlet being coaxial with the structural material outlet. The fluid outlet may be located at the center of the structural material outlet. This embodiment provides a low complexity configuration.

[0020] According to one embodiment, the apparatus includes a cooling device for cooling the extruded hollow core bead to accelerate solidification. The cooling device may be provided downstream of the structural material outlet. Additionally or alternatively, the cooling device may be integrated into the structural material outlet. The cooling device may be based on the physical principles of conduction cooling, convection cooling, or a combination of both. In one embodiment, a cooling channel for a cooling liquid, e.g., water, is provided in the nozzle at the structural material outlet. Additionally or alternatively, the cooling device may include a cooling outlet located downstream of the structural material outlet to guide a cooling fluid, e.g., cooling air and / or water mist, onto the extruded bead of structural material. The cooling outlet may include one or more cooling pipes located around the structural material outlet. In one embodiment, the cooling device includes a single cooling outlet configured as a ring and arranged concentrically around the structural material outlet. The provision of a cooling device in this embodiment allows for faster solidification of the extruded structural material. This increases the build-up speed because the structural material of the production pass of the slice hardens faster, meaning that production passes of adjacent slices can be stacked more quickly on top of a previously laid-out bead.

[0021] According to one embodiment, the apparatus includes a heating device for heating the solidified bead extruded from the structural material outlet and contacting the hollow core bead. In one embodiment, the heating device includes one or more heating outlets, which may be located at the bottom of the structural material outlet adjacent to the pre-laid bead. The heating device may be configured to heat a fluid, such as a gas, to a temperature that can melt the pre-laid, at least partially solidified bead. The heating device may also include a laser for heating the pre-laid bead. The melted bead allows for better adhesion between the pre-laid bead and a bead extruded from the structural material outlet, for example, stacked on top of the melted bead. This embodiment enables the production of structures with great stability because the heating device creates a strong connection between the stacked beads. It also enables the production of very large parts with long layer cycle times.

[0022] In one embodiment, the apparatus further includes a closing mechanism, which may be incorporated into the nozzle, for cutting the extruded hollow core bead. The closing mechanism may be a mechanical closing mechanism, for example, a plate-shaped stripper. It may also be implemented by generating a vacuum within the hollow core bead via a fluid pressure regulating device and a fluid outlet. Furthermore, the apparatus may include a puncturing component, which may be attached to the nozzle, for puncturing the extruded hollow core bead, for example, from the outside, and this puncturing component may be controlled by the above-mentioned control unit. If over-expansion of the bead cannot be controlled by any of the above-mentioned methods, for example, the control unit may control the puncturing component to puncture the extruded hollow core bead so as to avoid further over-expansion of the bead.

[0023] The present invention further relates to an assembly for additive manufacturing of a structure, preferably an architectural structure. The assembly comprises an extruder having an extruder outlet, a melting device for melting a raw material, a conveying device for conveying the molten raw material to the extruder outlet, a fluid source for providing a fluid, and an apparatus according to one of the above-described embodiments. The structure and / or the raw material may be configured according to the above-described embodiments. The extruder outlet may have a single orifice, for example, a circular or rectangular orifice. Furthermore, the extruder may have an extruder inlet, which may represent a funnel for inserting the raw material, preferably a granular raw material. The extruder may, for example, represent an elongated shape having a circular or rectangular cross-section, and the extruder outlet and the extruder inlet are provided on both sides of the extruder. The extruder may have a housing, which may form the extruder inlet and the extruder outlet. The conveying device may be configured as a spindle for conveying the raw material introduced at the extruder inlet to the extruder outlet. The spindle may be located within the extruder housing, and the extruder housing and the spindle are preferably oriented coaxially with each other. The extruder may further comprise a spindle drive, such as an electric motor, for driving the rotational movement of the spindle. The spindle drive and the spindle may be indirectly connected via a gearbox.

[0024] The assembly further includes a melting device for melting the extruder raw material, for example, the raw material introduced into the extruder inlet. The melting device may be provided inside or outside the extruder housing, but may also be integrated into the housing. In one embodiment, the melting device is ring-shaped and / or coaxially positioned with the housing, the conveying device, the extruder outlet, or a combination thereof. The melting device may be electrically actuated and / or actuated by a fluid, for example, moisture. The melting device may extend along the conveying device, for example, along more than 20%, preferably more than 30%, of the axial length of the conveying device. The melting device may include one or more heating bands that can be electrically actuated. The nozzle of the apparatus according to one of the aforementioned embodiments is coupled to the extruder outlet to receive the melted raw material. For example, the nozzle inlet is coupled to the extruder outlet, and the raw material melted by the extruder is conveyed through the extruder outlet to the nozzle inlet and from the nozzle inlet to the structural material outlet to extrude the hollow core bead. Furthermore, the conveying device of the extruder may be configured to convey the melted raw material not only through the extruder but also through the nozzle. The fluid outlet of the device is coupled to a fluid source for receiving the fluid, for example by a pipe.For an understanding of the individual features and their advantages, reference is made to the above-described embodiments of the construction of the present invention.

[0025] The present invention further relates to a system for additive manufacturing of a structure, preferably an architectural structure, comprising an assembly according to the aforementioned embodiment and a movement mechanism for moving the nozzle's structural material outlet along a predetermined manufacturing path. The movement mechanism can be a robot, for example, a 5-axis, 6-axis, or 7-axis robot. The robot can be a conventional industrial robot operating within a protective housing, for example, a protective fence. Alternatively, the robot can be a collaborative robot configured to work alongside a human without any protective device between them. In another embodiment, the movement mechanism comprises a positioning device having an x-axis positioning mechanism, a y-axis positioning mechanism, and a z-axis positioning mechanism configured to position the structural material outlet along three Cartesian coordinates. The movement mechanism can also be configured in different ways.

[0026] The system may include a control unit having a memory, e.g., a non-volatile memory, for storing the production paths of different slices for producing a structure. The control unit may be configured to control the movement mechanism so that the structural material outlet of the nozzle moves along the production path of each slice. Additionally or alternatively, the control unit may be configured to control the extruder, e.g., a conveying device and / or a heating device, to coordinate the heating and conveying of the raw material to the structural material outlet of the nozzle with the nozzle position, its movement speed, and each of the production paths. If the structural material outlet of the nozzle is moved at a faster speed by the movement mechanism, the control unit must, for example, increase the power of the heating device and accelerate the conveying device to provide a higher throughput of the molten raw material. If the movement mechanism is configured as a robot, the extruder with the nozzle may be attached to the end effector of the robot.

[0027] Furthermore, the present invention relates to a method for generating control data for an apparatus, assembly, or system according to one of the aforementioned embodiments for additive manufacturing of a structure, preferably an architectural structure. The control data may be data that can be loaded into a memory of a control unit to control a fluid pressure regulation device. Alternatively or additionally, the control data may be live-streamed to the control unit. The control data may serve as data on which the control unit controls the fluid pressure regulation device. The method includes, for example, obtaining a manufacturing path defined by a plurality of points from a slice of a three-dimensional model of the structure generated by the slicer software described above. Alternatively, the manufacturing path may be a manufacturing path that is not based on a three-dimensional model but is designed using a set of points and / or curves in three-dimensional space as described above. According to the method of the present invention, the geometry of the manufacturing path is analyzed. Analyzing the geometry may include determining curvature, slope, degree of rotation, and / or other geometric parameters at a plurality of points of the manufacturing path. Based on the analyzed geometry, the method of the present invention assigns pressure values ​​to a plurality of points of the manufacturing path. At the same time, the method may assign to each of a plurality of points in the manufacturing path an orientation and / or rotational position of the nozzle about its central axis, the orientation and / or rotational position of the nozzle about its central axis being determined to optimize the manufacturing quality of the hollow core bead.For an understanding of the individual features of the method of the present invention and their advantages, reference is made to the disclosure above in relation to the apparatus for additive manufacturing of structures.

[0028] According to one embodiment, the analysis of the geometric shape of the production path comprises determining the degree of rotation of the production path at a plurality of points, and the step of assigning pressure values ​​to the plurality of points comprises assigning lower pressure values ​​to points of the production path at which a higher degree of rotation has been determined than to points of the production path at which a lower degree of rotation has been determined. In other words, if the production path exhibits a high degree of rotation, for example a corner, the method according to the invention assigns a lower pressure value to that point than to parts of the production path at which the degree of rotation is significantly smaller, for example a production path corresponding to a straight line. This embodiment has the advantage that at locations where the production path exhibits a high degree of rotation, the inner diameter of the extrusion bead is reduced, reducing the pressure of the fluid introduced into the hollow core of the extrusion bead, thereby avoiding over-expansion of the bead.

[0029] Additionally or alternatively, analyzing the geometry of the manufacturing path may include determining whether a self-intersection of the manufacturing path exists at one or more of the plurality of points. In this case, the method may generate an adjusted tool path with no or reduced self-intersections at one or more of the plurality of points. Alternatively or additionally, preferably, if self-intersections cannot be avoided by adjusting the tool path, assigning pressure values ​​to the plurality of points may include assigning a lower pressure value to a point where a self-intersection of the manufacturing path exists compared to a pressure value that would be assigned to that point if no self-intersection exists. This adaptation of the pressure to the presence of self-intersections ensures that good manufacturing quality is guaranteed even in such complex situations. If the pressure is not adapted to such self-intersections, an increase in pressure may occur, resulting in over-expansion and potentially destruction of the hollow core bead. At the same time, the manufacturing path may be adjusted at the intersection to push the bead down to the previous layer when printing the first line of intersection and then slightly lift the nozzle for the point of intersection. Additionally or alternatively, analyzing the geometry of the production path includes determining whether there is a start of the production path at one of the plurality of points, and assigning pressure values ​​to the plurality of points includes assigning a lower pressure value to points in the production path that have a start of the production path than points in the production path that do not have a start of the production path.

[0030] At the same time, in all of the above cases, i.e., when a high degree of rotation and / or self-intersection and / or the beginning of a manufacturing path are determined, the method may generate control data for the extruder, based on which the control unit of the above-mentioned apparatus may control the extruder. The control data for the extruder may include data for controlling the extruder so that the extruded hollow core bead exhibits a larger wall thickness or transitions to a completely solid bead at the respective position, compared to a situation in which a lower degree of rotation and / or no self-intersection and / or no beginning are determined. The control data for the extruder and the assigned pressure values ​​may be aligned with each other to produce a bead having the desired configuration. This ensures that good manufacturing quality is maintained even in complex geometries, i.e., the manufactured structure exhibits a shape very close to the desired shape, even in complex geometric situations.

[0031] According to one embodiment, analyzing the geometry of the production path includes determining a degree of rotation of the production path at one of a plurality of points. The method according to this embodiment further includes comparing the determined degree of rotation of the production path at the point with a predetermined limit value and, if the determined degree of rotation exceeds the predetermined limit value, adjusting the production path to reduce the degree of rotation at the point. The method may require the absence of unrounded or chamfered corners and / or the absence of curvatures exceeding a predetermined threshold. This method step ensures that, even in situations where the geometry of the production path does not allow the apparatus, assembly, or system of the present invention to provide high-quality printing, high-quality production is still possible due to appropriate adjustment of the production path.

[0032] If the degree of rotation at a certain point in the production path cannot be adjusted below a predetermined limit, the pressure value assigned to that point may be set to atmospheric pressure or even below atmospheric pressure, such as 0 bar. This results in the extruded bead transitioning at the respective location to a solid bead, or at least to a hollow-core bead with a larger wall thickness. At the same time, the method may generate control data for the extruder, as described above, that controls the extruder so that the extruded hollow-core bead at the respective location exhibits a larger wall thickness or transitions to a completely solid bead. The control data for the extruder and the assigned pressure value may be aligned with each other to produce a bead with a desired configuration. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 shows a robot for additive manufacturing of architectural structures according to an embodiment of the invention. [Figure 2] FIG. 2 illustrates an assembly and apparatus for additive manufacturing of the robotic architectural structure of FIG. 1 according to an embodiment of the present invention. [Figure 3] , [Figure 4] , [Figure 5] 3-5 show perspective and cross-sectional views of a nozzle of the apparatus of FIG. 2 according to an embodiment of the present invention. [Figure 6] , [Figure 7] , [Figure 8] 6-8 show perspective and cross-sectional views of a nozzle of the apparatus of FIG. 2 according to another embodiment of the present invention. [Figure 9] FIG. 9 shows a flowchart of a method for generating control data for the robot of FIG. 1 according to an embodiment of the present invention. [Figure 10] 10a and 10b illustrate a production path defined by a number of points and pressure values ​​assigned to the points, according to an embodiment of the present invention. [Figure 11] FIG. 11 shows a flowchart of a method for manufacturing an architectural structure based on control data generated by the method according to FIG. 9 according to an embodiment of the present invention. [Figure 12] FIG. 12 illustrates the relative positions of different beads according to an embodiment of the present invention. [Figure 13] FIG. 13 illustrates different cross-sectional shapes of hollow core beads according to embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 illustrates a system 1 for manufacturing an architectural structure, comprising a mobile mechanism 2 and an assembly 3 for additively manufacturing the architectural structure. In this embodiment, the mobile mechanism 2 is a robot, preferably a conventional six-axis industrial robot. The robot 2 comprises five different joints 4 connected by links 5 that form a kinematic link from a base 2a to an end effector 7 at the distal end of the robot 2. Each of the joints 4 of the robot 2 comprises a drive for moving the two links 5 attached to the respective joint 4 relative to each other. The drives of the joints 4 are controllable via a control unit 6 of the robot 2. When the control unit 6 provides a target position and orientation for the end effector 7 of the robot 2, the control unit 6 is configured to actuate the different drives of the joints 4 so that the end effector 7 is moved to the desired target position and exhibits the desired target orientation. When the control unit 6 provides a manufacturing path along which the robot 2 should move the end effector 7, the control unit 6 is configured to control the different drives of the joints 4 so that the end effector 7 follows the manufacturing path with the desired orientation.

[0035] The different drives of the joints 4 of the robot 2 are connected to the control unit 6 by wires and / or wirelessly. The control unit 6 comprises a memory, preferably a non-volatile memory, for storing manufacturing paths of different slices of a three-dimensional model of an architectural structure to be manufactured by the system 1. Each of the slices may be a planar or non-planar slice. In an alternative embodiment, the stored manufacturing paths are not obtained from slices of the three-dimensional model, but are paths designed by points and / or curves in three-dimensional space, as described above. Additionally, the control unit 6 comprises a processor configured to move the end effector 7 of the robot 2 along the manufacturing path of a first slice stored in the memory of the control unit 6, then advance the end effector 7 of the robot 2 to a position on a second slice stored in the memory of the control unit 6, move the end effector 7 along the manufacturing path of the second slice, advance the end effector 7 to a third slice, etc.

[0036] FIG. 2 shows an assembly 3 for additive manufacturing of architectural structures for the robot 2 of FIG. 1. The assembly 3 is attached, preferably removably attached, to the end effector 7 of the robot 2. The assembly 3 includes an extruder 8, a fluid source 9, and an apparatus 10 for additive manufacturing of architectural structures. The extruder 8 includes an elongated, preferably cylindrical, housing 11 having an interior workspace 12 in which a conveying device 13, preferably a spindle, is rotatably supported. A drive 14, preferably an electric motor, is provided on one side of the housing 11, rotating the spindle 13. On the opposite side, the housing 11 displays an extruder outlet 15, which in this embodiment is formed as a cylindrical orifice. Additionally, the extruder 8 has an extruder inlet 16, which in this embodiment is formed as a funnel on the side of the housing 11. The extruder can have different configurations, for example, configurations in which components are integrated into the extruder housing. The inlet 16 is located toward the opposite side of the housing 11 from the extruder outlet 15.

[0037] A melting device 17 is provided within the housing 11 and extends substantially along the majority of the axial length of the working space 12 and the spindle 13. The melting device 17 is formed by a plurality of heating bands integrated into the housing 11 of the extruder 8. In this embodiment, the melting device 17 comprises a plurality of heating bands electrically connected to a melting power source 18. The melting source 18 may be configured to circulate an electric current through the heating bands of the melting device 17. The extruder 8 in this embodiment is configured to operate with granular feedstock introduced into a funnel at the extruder inlet 16. The granular feedstock inserted into the working space 12 through the inlet 16 is transported by the spindle 13, driven by the motor 14, towards the extruder outlet 15 while being melted by the melting device 17.

[0038] The apparatus 10 for additive manufacturing of architectural structures includes a nozzle 20, which will be described in detail below with reference to FIGS. 3-8. Additionally, the apparatus 10 of this embodiment includes a fluid pressure regulating device 21, a control unit 22, a sensing device 24, a cooling device 25, and a heating device 26. The nozzle 20 includes a nozzle inlet 28 in fluid communication with the extruder outlet 15. The nozzle 20 is coupled, preferably removably coupled, to a face of the housing 11 of the extruder 8 that displays the extruder outlet 15. The nozzle 20 displays an elongated profile having the nozzle inlet 28 on one face and a structural material outlet 27 on the opposite face. The nozzle 20 is configured to extrude a structural material from the structural material outlet 27 to form a hollow core bead 30, the structural material being introduced from the extruder outlet 28 into the nozzle inlet 28.

[0039] The hollow core bead 30 extruded from the nozzle 20 may have different cross-sectional shapes, some of which are shown in FIG. 13. As shown in FIGS. 13A-13D, the hollow core bead 30 may have a cross-sectional shape that is hollow oval, e.g., a hollow circle (see FIG. 10A) or a hollow oval (see FIG. 10B). The hollow circle may have internal reinforcing struts, as shown in FIG. 10C. In an alternative embodiment, the cross-section of the hollow core bead 30 exhibits a circular outer wall but an inner wall that deviates from a purely circular shape, e.g., by exhibiting one or more protruding or recessed portions, as shown in FIG. 10D. Alternatively, the extruded hollow core bead 30 may have a cross-sectional shape that is hollow polygonal, e.g., a hollow rectangle or hollow pentagon, preferably with additional internal reinforcing struts, as shown in FIGS. 10G and H. In alternative embodiments, the extruded hollow core bead 30 exhibits a solid polygonal or solid elliptical cross-sectional shape, but includes multiple polygonal or elliptical voids. Figures 10E and 10F show embodiments in which the hollow core bead 30 exhibits a solid circular cross-sectional shape with four (see Figure 10E) or sixteen (see Figure 10F) internal voids. The extruded hollow core bead 30 may have cross-sectional shapes different from those shown in Figures 10A-10H. To form hollow core beads 30 having the respective cross-sectional shapes, the nozzle 20 is provided with a corresponding structural pattern, i.e., a corresponding die pattern. To form a hollow core bead 30 having a hollow circular cross-sectional shape, as shown in Figure 13A, the nozzle 20 exhibits, for example, barbs 29 for dividing the molten raw material into a thin wall and a hollow core.

[0040] The apparatus 10 further includes a fluid outlet 31 for injecting a fluid into the hollow core of the extruded bead 30. In the embodiment shown in FIG. 2, the fluid outlet 31 is located coaxially and centrally with the structural material outlet 27. The fluid outlet 31 is in fluid communication with a fluid pressure regulating device 21, which is in fluid communication with the fluid source 9. In an alternative embodiment, the fluid outlet 31 is not integrated into the nozzle 20 but is attached to the side of the nozzle 20 and / or is located separately therefrom. In this embodiment, the fluid pressure regulating device 21 includes a flow control valve for controlling the pressure of the fluid injected into the hollow core of the extruded bead 30 via the fluid outlet 31. Additionally, in this embodiment, the fluid pressure regulating device 21 includes a pressure relief valve for relieving overpressure present in the hollow core of the extruded bead 30. The flow control valve and the pressure relief valve of the fluid pressure regulating device 21 are adjustable and controllable via the control unit 22. In an alternative embodiment, the fluid pressure regulating device 21 includes only a flow control valve or a pressure relief valve.

[0041] Additionally, the apparatus 10 includes a cooling device 25 including a conduction cooling unit 32 and a convection cooling unit 33. The conduction cooling unit 32 includes a cooling coil integrated into the nozzle 20 adjacent to the structural material outlet 27, which is fluidly connected to a conduction fluid source 34 via a fluid pipe. The conduction fluid source 34 is configured to circulate a cooling fluid, e.g., water, through the cooling coil integrated into the nozzle 20. The convection cooling unit 33 includes a cooling outlet for discharging a cooling gas onto the extruded hollow core bead 30. The cooling outlet is in fluid communication with a convection cooling gas source 35. The cooling gas source 35 is configured to deliver a cooling gas, e.g., air, to the cooling outlet for blowing onto the extruded hollow core bead 30. Both the cooling units 32 and 33 are configured to cool the extruded hollow core bead 30 to accelerate solidification and hardening. Both the cooling sources 34 and 35 are controllable via the control unit 22.

[0042] Additionally, the apparatus 10 includes a heating device 36 having a heating outlet for emitting heated gas onto the bead 37 pre-laid out by the system 1. The heating device 36 includes a heated fluid source 38, e.g., a heated gas source, preferably a heated air source, in fluid communication with the heating outlet. The heating device 36 is controllable via the control unit 22 and configured to emit heated gas onto the pre-laid out bead 37 so as to melt the surface of the bead 37 and strengthen the connection between the pre-laid out bead 37 and the currently laid out bead 30.

[0043] Furthermore, the apparatus 10 comprises a sensing device 24 for sensing geometric parameters of the extruded hollow core bead 30. In this embodiment, the sensing device 24 is configured to determine the wall thickness and extrusion height of the extruded hollow core bead 30. The sensing device 24 is electrically connected to the control unit 22.

[0044] The control unit 22 is configured to control the heating fluid source 38 of the heating device 36, the motor 14 and melting device 17 of the extruder 8, the fluid source 9 and fluid pressure regulating device 21, and the cooling sources 34 and 35 of the cooling device 25. Furthermore, the control unit 22 is configured to control one or more of these devices based on data determined by the sensing device 24. In this embodiment, only one control unit 22 is provided to control all of the devices. In alternative embodiments, one or more of these devices may have separate control units. Additionally, the control unit 22 or separate control units of one or more devices may be part of the control unit 6 for controlling the robot 2. The control unit 22 is configured to control the assembly 3 according to the method described in connection with FIG. 11 below.

[0045] 3-5 illustrate a first embodiment of the nozzle 20 of the apparatus 10 shown in FIG. 2. The nozzle 20 comprises an elongated body having a nozzle inlet 28 and a structural material outlet 27. The nozzle inlet 28 is located on one side of the elongated body, and the structural material outlet 27 is located on the opposite side of the body. The nozzle 20 exhibits an essentially cylindrical shape. As shown in FIG. 4, the inlet 28 comprises five orifices, four of which are located in a square, with the fifth orifice located in the center of the square. The four outer orifices open into channels 39 that extend axially inward along the nozzle 20, which move radially outward inside the nozzle 20 and terminate in a ring-shaped channel having the shape of a hollow cylinder. At the same time, the central orifice of the nozzle inlet 28 is fluidly connected to a central channel 40 that extends axially centrally along the nozzle 20 and terminates at the center of the ring-shaped channel. As shown in Figure 5, the ring-shaped channel and a portion of the central channel 40 located at its center are in fluid communication with each other to form a die for forming a bead 30 having a hollow circular cross section and two intersecting reinforcing struts at its center. The die has a specific axial extension along the nozzle 20 and terminates in a corresponding component material outlet 27.

[0046] The die terminating at the component material outlet 27 of the nozzle 20 in Figures 3-5 exhibits four voids in its cross-sectional shape, which collectively form the fluid outlet 31 in this embodiment. The four voids forming the fluid outlets are provided by four chambers that are not fluidly connected to either the channel 39 or the channel 40. The chambers have a quarter-circle cross-sectional shape with the cross-section oriented perpendicular to the axial direction of the nozzle 20. As can be derived from Figure 5, the chambers extend axially of the nozzle 20 from the fluid outlet 31 toward the nozzle inlet 28 before extending radially inward to connect to a fluid inlet pipe 42 extending perpendicular to the axial direction of the nozzle 20. Two of these chambers connect to the fluid inlet pipe 42 extending from the right side of the nozzle 20, while the other two chambers connect to a fluid inlet pipe extending from the left side of the nozzle 20. Both fluid inlet pipes terminate at the sides of the nozzle 20 and collectively form a fluid inlet that is fluidly connected to the fluid pressure regulating device 21 shown in Figure 2.

[0047] When nozzle 20 of FIGS. 3-5 is attached to extruder 8 so that extruder outlet 15 is in fluid communication with nozzle inlet 28, spindle 13 of extruder 8 conveys molten feedstock to nozzle inlet 28 and extrudes it through channels 39 and 40 into a hollow cylinder having two intersecting reinforcing struts. Simultaneously, fluid source 9 of FIG. 2 provides fluid that is injected into fluid inlet pipe 42 to flow through four separate chambers to fluid outlet 31 for injection into the hollow core of extruded bead 30. The entire nozzle 20 of FIGS. 3-5 can be integrally formed from metal and / or polymer, for example, preferably by additive manufacturing.

[0048] FIGS. 6-8 illustrate an alternative embodiment of the nozzle 20 of the apparatus 10 of FIG. 2. The nozzle 20 of FIGS. 6-8 corresponds to the nozzle 20 of FIGS. 3-5, except for the differences described below. In contrast to the embodiment of FIGS. 3-5, the embodiment of FIGS. 6-8 does not include a central orifice in the nozzle inlet 28. In contrast, the nozzle inlet 28 includes only four orifices arranged in a rectangular shape, as shown in FIG. 7. Similar to the four rectangular orifices in the embodiment of FIGS. 3-5, the orifices in the embodiment of FIGS. 6-8 extend into axially extending channels 39 inside the nozzle 20 and then extend radially outward to terminate in a ring-shaped channel. The ring-shaped channel extends a certain distance along the axial direction of the nozzle 20 to form a die and terminate in the structural material outlet 27. As can be derived from FIGS. 6 and 8, the structural material outlet 27 of the embodiment of FIGS. 6-8 has a hollow circular cross-sectional shape without intersecting reinforcing struts. 6-8, the fluid outlet 31 is formed by a single orifice concentrically disposed in the center of the structural material outlet 27. As in the embodiment of FIGS. 3-5, the fluid outlet 31 is in fluid communication with two fluid inlet pipes 42 that extend perpendicular to the axial direction of the nozzle 20 and terminate at the right and left sides of the nozzle, respectively.

[0049] As discussed above in connection with Figure 13, nozzle 20 can also be configured to extrude hollow core beads having cross-sectional shapes different from those shown in the embodiments of Figures 3-8. Nozzle 20 extruded beads having such different cross-sectional shapes can be configured in accordance with the principles of the embodiments of Figures 3-8 or differently.

[0050] FIG. 9 illustrates an embodiment of a method for generating control data for the apparatus 10 of FIG. 2, the assembly 3 of FIG. 2, and the robot 2 of FIG. 1. In a first step I, the method obtains a manufacturing path M defined by a plurality of points A, as shown in FIG. 10A. In this embodiment, the manufacturing path M is obtained from a slice of a three-dimensional model of an architectural structure to be manufactured using the system 1 of FIG. 1. FIG. 10A illustrates points A1-A7 at key locations of the manufacturing path M, but does not show points of the manufacturing path between A1-A7. As described above, the three-dimensional model of the architectural structure is divided into a plurality of slices, for example, by slicing software, each of which includes a manufacturing path such as that shown in FIG. 10A, and the different slices stacked on top of each other collectively build the architectural structure.

[0051] In a second step II, the geometric shape of the manufacturing path M is analyzed. In this step II, in this embodiment, the degree of rotation of the manufacturing path M is determined. As shown in FIG. 10A, the manufacturing path M exhibits very high degrees of rotation at corner points A2, A4, and A6, but moderate degrees of rotation at midpoints A1, A3, A5, and A7.

[0052] In a third step III, the degree of rotation determined in step II is compared with a predetermined limit value. If it is determined in step III that the limit value at a particular point A is exceeded, the manufacturing path M is adjusted in the next step IV at that particular point A. In this embodiment, as shown in FIG. 10A , the manufacturing path M is adjusted to the manufacturing path M′ so that the degree of rotation of the adjusted manufacturing path M′ does not exceed the predetermined limit value at any position A. This adjustment of the manufacturing path M in step IV ensures that the manufacturing path does not exhibit any position that would lead to a blockage of the fluid injected into the hollow core bead, which could result in over-expansion of the extruded bead.

[0053] In the next step V, pressure values ​​P1 to P7 of the fluid injected into the hollow core of the extrusion bead 30 through the fluid outlet 31 are assigned to different points A1 to A7 of the manufacturing path M'. The pressure values ​​P assigned to different points A of the manufacturing path M' are shown in FIG. 10B. This step V involves assigning a pressure value P to points A of the manufacturing path M' that exhibit a high degree of rotation that is lower than the pressure value P assigned to points A of the manufacturing path M' that exhibit a moderate degree of rotation. In the specific example of FIGS. 10A and 10B, the degree of rotation at points A2, A4, and A6 of the manufacturing path M' is relatively high, which means that relatively low pressure values ​​P2, P4, and P6 are assigned to those points. In contrast, the degree of rotation at points A1, A3, A5, and A7 of the manufacturing path M' is relatively medium, which means that relatively high pressure values ​​P1, P3, P5, and P7 are assigned to those points.

[0054] 9 ensures that passages of the production path M' where a large degree of rotation exists and which pose a greater flow resistance to the fluid being injected into the hollow core of the extruded bead 30 exhibit lower pressure values ​​P, thereby preventing over-expansion of the extruded bead 30 and ensuring optimal print quality. When assigning different pressure values ​​P to different points A in step V, it may be analyzed whether the production path M' has a self-intersection point at one of its points A, for example, when the production path M' of a single slice intersects itself at a particular point A. In that case, a lower pressure value P may be assigned to the point A where a self-intersection exists than the pressure value that would be assigned to that point if a self-intersection did not exist. This ensures good print quality even in the case of self-intersecting print paths.

[0055] 9 may include analyzing whether a first production pass M of a first slice indicates two bead portions that will contact each other in the same slice plane when the first production pass is performed using the system 1. In that case, it may be analyzed whether an adjacent second slice includes a second production pass M that, when performed by the system 1, results in a further bead portion that contacts at least one of the two bead portions of the first slice. In that case, step IV of the method of FIG. 9 may include shifting at least a portion of the production pass M of the first slice in a direction perpendicular to the first slice to a position between the first slice and the second slice, so that the bead portion resulting from the shifted production pass contacts both the other bead portion of the first slice and the bead portion of the second slice. For example, when a hollow core bead with a circular cross section is extruded, as shown in Figure 12, the portion of the production path for bead B2 on the left side of Figure 12 is initially located in the same slicing plane as the portion of the production path for bead B1, but is shifted perpendicular to the respective slicing planes so that extruded bead B2 is located between adjacent beads B1 in two adjacent rows. This means that bead B2 has a contact surface with not only a single bead B1 but also two adjacent beads B1, thereby increasing the strength of the manufactured building product.

[0056] Step V may include storing the generated control data, i.e., the different points A of the adjusted manufacturing path M' and the different pressure values ​​P assigned to each point, preferably in the form of a look-up table on a physical storage medium, e.g., a non-volatile memory. The method described in conjunction with FIG. 9, including method steps I-V, may be executed on a computer. Thus, the method may be a computer-implemented method. The method may be part of the slicer software, or may be executed by separate software into which the output of the slicer software is loaded, e.g., in G-code format.

[0057] Figure 11 shows a method for additive manufacturing of an architectural structure using the system 1 of Figure 1, using control data generated by a method according to the embodiment of Figure 9. The method described in relation to Figure 11 is performed by control units 6 and 22 of Figures 1 and 2. In this embodiment, control unit 22 carries a non-volatile memory in which the control data generated by the method of Figure 9 is stored.

[0058] In a first step M1, the control unit 6 of the system 1 determines a next point A of the production path M' to which the end effector 7 of the robot 2 must be moved. This next point A is transmitted to the control unit 22, which in a next step M2 determines the different operating parameters of the assembly 3. In particular, the control unit 22 determines the pressure value P to be assigned to the next point A based on control data stored in a non-volatile memory. The control unit 22 also determines the operating parameters of the heating device 26, the cooling device 25, the melting device 17 and the motor 14 of the extruder 8. In a next step M3, the control unit 6 moves the end effector 7 of the robot 2 to the next point A, and the control unit 22 adjusts the operating parameters of the different systems to the determined target values.

[0059] Specifically, in step M3, the control unit 22 adjusts the fluid pressure regulating device 21 to inject fluid into the hollow core of the bead 30 through the fluid outlet 31 at point A of the production path M' with a pressure value P determined by the control unit 22 based on control data stored in the non-volatile memory of the control unit 22. Simultaneously, the heating device 26 is controlled to melt the adjacent previously laid bead 37 to improve the connection between the currently laid bead 30 and the previously laid bead 37. Similarly, the control unit 22 operates the cooling devices, i.e., the conduction cooling unit 32 and the convection cooling unit 33, to efficiently solidify the extruded hollow core bead 30. If the pressure in the hollow core of the extruded bead 30 rises above a predetermined overpressure, the pressure relief valve of the fluid pressure regulating device 21 opens to relieve the overpressure, thus ensuring the desired operating conditions.

[0060] During the process, the sensing device 24 determines the wall thickness and extrusion height of the extrusion bead 30 in step M4. The control unit 22 compares the determined wall thickness and extrusion height with predetermined target values. If there is a deviation, the control unit 22 returns to step M3 and adjusts the pressure of the fluid injected into the hollow core of the extrusion bead 30 via the fluid pressure regulating device 21 and / or adjusts the flow rate of the molten material, i.e., increases or decreases it to a non-zero value, by adjusting the speed of the electric motor 14 driving the spindle 13. The sensing device 24 again determines the wall thickness and extrusion height of the extrusion hollow core bead 30 in step M4, and the control unit 22 again adjusts the fluid pressure and / or the flow rate of the molten material in step M3 if there is still a deviation from the target values ​​of the parameters determined by the sensing device 24. The method then returns to the beginning in step M1 to receive the next point A of the production path M' from the control unit 6 of the robot 2. [Explanation of symbols]

[0061] 1: System for additive manufacturing of additive structures 2: Robot 2a: base 3: Assembly for additive manufacturing of additive structures 4: Joint 5: Links 6: Control unit 7: End effector 8: Extruder 9: Fluid source 10: Equipment for additive manufacturing of additive structures 11: Housing 12:Workspace 13: Spindle 14: Motor 15: Extruder outlet 16: Extruder inlet 17, 18: Melting device 20: Nozzle 21: Fluid pressure regulating device 22: Control unit 24:Detection device 25, 32, 33, 34, 35: Cooling devices 26, 38: Heating devices 30, 37, B1, B2: Bead 39, 40: Channel 42: Fluid inlet pipe M, M': Manufacturing path A, P: Points on the path, pressure assigned to the points S: Cross section I: Obtaining a manufacturing pass II: Manufacturing path geometry analysis III: Geometry compared with limits IV: Adjust the manufacturing path based on the analysis V: Assigning pressure values ​​to points on the manufacturing path M1: Determine the next position M2: Determining the operating parameters for the system M3: Adjustment of fluid pressure regulating device M4: Determination of geometric parameters of extrusion beads

Claims

1. An apparatus (10) for additive manufacturing of a structure, preferably an architectural structure, said apparatus (10) comprising: a nozzle having a structural material outlet (27) configured to extrude structural material along a manufacturing path (M, M') defined by a plurality of points (A) in forming a hollow core bead (30); a fluid outlet (31) configured to inject a fluid into the hollow core of the extrusion bead (30); a fluid pressure regulating device (21) configured to regulate the pressure of the fluid injected into the hollow core of the extrusion bead (30) through the fluid outlet (31); a control unit (22) configured to determine a pressure value (P) to be assigned to a point (A) of the production path (M, M') and to control the fluid pressure regulating device (21) based on the determined pressure value (P); An apparatus (10) comprising:

2. 2. The apparatus (10) of claim 1, further comprising a sensing device (24) for determining at least one of a geometric parameter of the extrusion bead (30) and a parameter of the fluid in the hollow core of the extrusion bead (30), and the control unit (22) is configured to control the fluid pressure regulating device (21) based on the determined parameter.

3. 3. The apparatus (10) of claim 2, wherein the determined parameter is at least one of a wall thickness and an extrusion height of the extrusion bead (30).

4. 4. The apparatus (10) of any one of claims 1 to 3, wherein the fluid pressure regulating device (21) comprises a flow control valve for regulating the pressure of the fluid.

5. 5. The apparatus (10) of claim 1, further comprising a pressure relief valve for relieving overpressure within the hollow core of the extrusion bead (30).

6. 6. The apparatus (10) of claim 5, wherein the fluid pressure regulating device (21) comprises the pressure relief valve, the pressure relief valve being adjustable, and the control unit (22) is configured to adjust the adjustable pressure relief valve based on the determined pressure value (P).

7. 7. The apparatus (10) according to any one of claims 1 to 6, wherein the structural material outlet (27) is configured to extrude a hollow core bead (30) having at least one cross-sectional shape of a hollow polygon, preferably a hollow rectangle, a hollow oval, preferably a hollow circle, and a solid polygon or a solid oval containing one or more polygonal or oval voids.

8. 8. The apparatus (10) according to any one of claims 1 to 7, wherein the nozzle (20) comprises the fluid outlet (31), the fluid outlet (31) being formed coaxially with the structural material outlet (27).

9. 9. The apparatus (10) according to any one of claims 1 to 8, comprising a cooling device (25) for cooling the extruded hollow core bead (30) to accelerate solidification.

10. 10. The apparatus (10) according to any one of claims 1 to 9, comprising a heating device (26) for heating a solidified bead (37) that contacts the hollow core bead (30) extruded from the structural material outlet (27) to improve adhesion between the two beads (30, 37).

11. 11. An assembly (3) for additive manufacturing of a structure, preferably an architectural structure, said assembly (3) comprising: an extruder (8) having an extruder outlet (28); a melting device (17) for melting raw material; a conveying device (13) for conveying the molten raw material to the extruder outlet (28); a fluid source (9) for providing a fluid; and an apparatus (10) according to any one of claims 1 to 10, wherein the nozzle (20) of the apparatus (10) is coupled to the extruder outlet (28) for receiving the molten raw material, and the fluid outlet (31) is coupled to the fluid source (9) for receiving the fluid.

12. 12. A system (1) for additive manufacturing of structures, preferably architectural structures, comprising an assembly (3) according to claim 11 and a movement mechanism (2) for moving the structural material outlet (27) of the nozzle (20) along a predetermined manufacturing path (M, M').

13. 13. A method for generating control data for an apparatus (10) according to any one of claims 1 to 10, an assembly according to claim 11 or a system (1) according to claim 12 for additive manufacturing of a structure, preferably an architectural structure, said method comprising: (I) obtaining a manufacturing path (M, M') defined by a plurality of points (A); (II) analyzing the geometry of said manufacturing path (M, M') at said plurality of points (A); assigning (V) pressure values ​​(P) to the plurality of points (A) of the manufacturing path (M, M') based on the analyzed geometry; A method comprising:

14. 14. The method of claim 13, wherein analyzing (II) the geometry of the manufacturing path (M, M') includes determining a degree of rotation of the manufacturing path (M, M') at the plurality of points (A), and assigning (V) pressure values ​​(P) to the plurality of points (A) includes assigning lower pressure values ​​(P2, P4, P6) to points (A2, A4, A6) of the manufacturing path (M, M') at which a higher degree of rotation is determined than to points (A1, A3, A5, A7) of the manufacturing path (M, M') at which a lower degree of rotation is determined.

15. 15. The method of claim 13 or 14, wherein (II) analyzing the geometric shape of the manufacturing path (M, M') includes determining a degree of rotation of the manufacturing path (M, M') at one of the plurality of points (A), the method further comprising: (III) comparing the determined degree of rotation of the manufacturing path (M) at that point (A) with a predetermined limit value; and (IV) adjusting the manufacturing path (M') to reduce the degree of rotation at that point (A2, A4, A6) if the determined degree of rotation exceeds the predetermined limit value.

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