System for extruding building material, provided with a device for measuring the width of extruded beads

Abstract

Disclosed is a system for extruding beads of building material for a robot (50) for the additive manufacturing of architectural structures (60), comprising: a printhead (30) for printing beads of building material, comprising an inlet mouth (31) and an extrusion nozzle (34) configured to form a bead (62) of building material, said printhead (30) being intended to be moved by the robot (50) along a predetermined path, from upstream to downstream, to form an architectural structure (60) by stacking layers of said extruded beads (62); a feed circuit (20) for feeding material to said printhead (30) comprising a storage tank (10) and a feed line (21); and a pump (22, 51) for controlling the flow of building material, said pump being arranged between said storage tank and said extrusion nozzle. The system further comprises a device (40) for contactlessly measuring the width of the extruded bead (62) upstream of said extrusion nozzle (34), said measuring device (40) being supported by said printhead (30).

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: BUILDING MATERIAL EXTRUSION SYSTEM EQUIPPED WITH A DEVICE FOR MEASURING THE WIDTH OF THE EXTRUDED CORDS

[0003] Technical field of the invention

[0004] The invention relates to the additive manufacturing of construction materials. The invention relates more particularly to a system for extruding construction material cords for a robot for the additive manufacturing of architectural structures by stacking successive layers of extruded cords. The invention also relates to a method for extruding construction material cords for a robot for the additive manufacturing of architectural structures.

[0005] Technological background

[0006] 3D printing of construction materials is a booming activity for which the applicant has already proposed numerous innovations to improve manufacturing processes.

[0007] Thus, the applicant has already proposed, in particular in applications WO20 18 / 051370, WO2018 / 229419, WO2019 / 048752, WO2019 / 038491 and WO2019 / 025698, systems for extruding beads of cementitious material for a robot for the additive manufacturing of architectural structures.

[0008] Throughout the text, the term "architectural structures" refers to both individual building elements (bridges, pillars, walls, street furniture, etc.), complete structures (buildings, houses, apartment blocks, etc.) and various architectural pieces (artistic works, sculptures, etc.).

[0009] The systems already proposed by the applicant provide numerous advantages over traditional techniques, including the possibility of creating complex shapes by adding successive layers of construction materials, the speed of construction operations, the reduction of costs and labor, improved safety on construction sites, etc.

[0010] These systems generally comprise a print head equipped with a construction material inlet and an extrusion nozzle (also referred to in the text as an "outlet nozzle") for extrusion beads of construction material, a circuit for supplying the inlet of the print head with construction material comprising a construction material storage tank, a pipe connecting the storage tank and the inlet of the print head, and a pump for feeding the pipe with construction material from the storage tank.

[0011] One of the challenges of 3D printing construction materials is that the material must be supplied in a rheological state that is compatible with pumping the material, i.e., fluid enough to be pumped from the storage tank and conveyed to the outlet nozzle, while its state must be viscous enough (i.e., less fluid) at the outlet of the extrusion nozzle to be able to form a self-supporting layer capable of supporting the next layer.

[0012] The quality of an architectural structure manufactured by such a cementitious material extrusion system depends in particular on the intra-layer adhesion and the section of the extruded cords.

[0013] It is therefore important to be able to control, at any point of the architectural structure, the section of the extradited cords in order to be able to certify that the architectural structure complies with the targeted specifications.

[0014] To do this, one known technique is to use a caliper to measure the width of the extradited cords at certain critical areas. Another solution is to use a scanner operated by an operator.

[0015] These solutions have many limitations, including the difficulty, or even impossibility, of accessing certain areas of the architectural structure, particularly when the extradited structure has a succession of overhangs or closed areas such as material domes. Another limitation of this solution lies in the time required to inspect an entire structure, particularly a complex one. Thus, the time saved by using a 3D printing system to manufacture the cement structure may be lost by the time required to inspect, a posteriori, the manufactured architectural structure. Finally, this solution does not allow for simple and satisfactory implementation of possible corrective measures if the inspection reveals beads that do not comply with the required specifications.

[0016] The inventors therefore sought to develop a solution that would overcome the limitations of known solutions, and in particular those linked to the a posteriori measurement of the section of the cords and the problem of access to the entire architectural structure.

[0017] Objectives of the invention

[0018] The invention therefore aims to provide a construction material extrusion system which makes it possible to simply and without constraints control the quality of the extruded cords.

[0019] The invention aims in particular to provide such a system which makes it possible to measure the width of the extradited cords during the manufacture of the architectural structure.

[0020] The invention also aims to provide such a system which allows corrective measures to be taken quickly if it turns out that the extradited cords do not comply with the required specifications or are approaching the authorized limits.

[0021] The invention also aims to provide, in at least one embodiment, such a system which makes it possible to measure the width of the extruded cords, whatever the geometry of the extruded part.

[0022] The invention also aims to provide, in at least one embodiment, such a system which makes it possible to measure the width of the extruded cords, regardless of the orientation and / or movement of the extrusion head.

[0023] Statement of the invention

[0024] To this end, the invention relates to a system for extruding building material cords for a robot for additive manufacturing of architectural structures comprising: a head for printing building material cords comprising a material inlet mouth and an extrusion nozzle extending around an extrusion axis and configured to form an extruded cord of building material, said print head being intended to be moved by the additive manufacturing robot along a predetermined trajectory, from upstream to downstream, to form an architectural structure by stacking layers of said extruded cords, a circuit for supplying building material to said print head comprising a building material storage tank and a building material supply line connecting said storage tank and said extrusion head,a pump for regulating the flow of construction material circulating in said extrusion system arranged between said storage tank and said extrusion nozzle.,

[0025] The system according to the invention is characterized in that it further comprises a device for contactless measurement of the width of the extruded bead upstream of said extrusion nozzle, said measuring device being carried by said print head and comprising three lasers associated with a unit for calculating the width of said bead from the data acquired by the lasers, said lasers being oriented towards said extruded bead, upstream of said extrusion nozzle, and arranged relative to each other in such a way that the projected light rays form a closed triangle surrounding said axis of said extrusion nozzle.

[0026] Throughout the text, unless otherwise indicated, the terms "upstream" and "downstream" are used to refer to the movement of the print head along the predetermined path. In other words, the bead upstream of the head corresponds to the bead that has just been extruded, while the downstream of the head corresponds to the part of the path that is about to receive a bead.

[0027] The system according to the invention therefore has the particularity of incorporating, on the print head, a device for non-contact measurement of the width of the bead extruded upstream of the extrusion nozzle on the predetermined trajectory. This means that the system is capable of measuring the width of the bead which has just been extruded by the print head. This extruded bead is located upstream of the extrusion nozzle on the predetermined trajectory followed by the print head to manufacture the architectural structure. Thus, the system can continuously measure, and during the manufacture of the manufactured part, the width of the beads extruded by the extrusion nozzle, just after their extrusion by the extrusion nozzle.

[0028] The system according to the invention therefore makes it possible to control, during printing, the width of the beads to guarantee the quality of the manufactured part and to be able, if necessary, to take corrective measures in real time if the measured width of the extruded bead proves to be non-compliant or tends towards a non-compliant value. These corrective measures may be modifications to the setpoints for the speed of movement of the print head or the extrusion flow rate of the cementitious material, to maintain the width of the extruded bead within the range of admissible values.

[0029] Furthermore and according to the invention, said measuring device comprises three lasers for acquiring data representative of the width of the extruded bead upstream of the extrusion nozzle, associated with a unit for calculating the width of said bead from said representative data acquired by the lasers, these lasers being oriented towards said extruded bead.

[0030] Thus, the measurement of the width of the extruded cord is obtained by using several lasers. The laser projects a light beam towards the cord and the associated computing unit allows a measurement of the cord width to be deduced from it. In combination, a camera can be used to also acquire an image of the extruded cord and the computing unit allows a measurement of the cord width to be deduced from it by processing the acquired image.

[0031] According to the invention, said measuring device comprises three lasers arranged relative to each other in such a way that all of the data acquired by all of the lasers cover at least one closed triangle surrounding said extrusion axis of said extrusion nozzle.

[0032] According to the invention, each laser is configured to project a rectilinear light beam. This facilitates width measurement since it eliminates the complex image processing required in the case of a sensor formed by an image acquisition camera.

[0033] Thus, the set of lasers makes it possible to cover at least one closed polygon (in this case a triangle) which surrounds the extrusion nozzle in such a way as to guarantee that the bead is visible to at least one sensor regardless of the orientation of the print head and regardless of the direction of movement of the print head. Thus, the lasers are fixed on the print head, which facilitates their mounting on the print head. The print head can be driven in any direction while guaranteeing that a width measurement can be carried out by one of the lasers, insofar as the set of lasers covers at least one closed triangle which surrounds the extrusion nozzle, and therefore necessarily the extruded bead.

[0034] According to the invention, the system comprises three lasers arranged relative to each other in such a way that the projected light rays form a closed triangle.

[0035] This ensures that the bead is visible to at least one laser, regardless of the orientation and direction of travel of the print head.

[0036] Advantageously and according to the invention, the system further comprises a unit for controlling the speed and movement of said print head along a predetermined trajectory, from upstream to downstream, and a unit for controlling said pump for regulating the flow rate of construction material. According to this advantageous variant, said device for measuring the width of the extruded beads is configured to transmit said width measurement to said speed and movement control unit and / or to said control unit of said regulation pump, so as to be able to control the speed of movement and / or said flow rate of construction material to said measured width of the extruded bead upstream of the extrusion nozzle.

[0037] The geometry of a bead of cementitious material extruded by a print head depends on the shape of the extrusion nozzle, the extrusion flow rate and the speed of movement of the print head. It can be assumed as a first approximation that a bead extruded at a flow rate d has a long ob shape characterized by a height h and a width l, linked to each other by the formula d / v = l ~ Xh, where v represents the speed of movement of the print head.

[0038] The height h is imposed by the vertical displacement of the print head between a previous extrusion layer and the layer currently being extruded. Also, the d / v ratio conditions the width of the bead being extruded.

[0039] The invention therefore provides for defining the width of the bead and controlling it during extrusion, by means of speed and flow rate instructions. This advantageous variant makes it possible in particular to control the speed of movement and flow rate instructions of the cementitious material to the actual instantaneous measurement of the width of the extruded bead.

[0040] The control pump that controls the flow rate of cementitious material in the system is arranged within the extrusion system between the storage tank and the extrusion nozzle. For example, this pump can be arranged between the storage tank and the supply line, to fill the supply line with construction material. According to another variant, this pump can be arranged directly within the print head, between the inlet mouth and the extrusion nozzle, to meter the cementitious material.

[0041] According to an advantageous variant of the invention, said print head comprises a metering pump configured to be able to convey the construction material from said inlet mouth to said extrusion nozzle and this metering pump forms said regulation pump.

[0042] According to this advantageous variant, the regulating pump is formed by a metering pump housed in the print head and configured to convey the construction material from said inlet mouth to said extrusion nozzle.

[0043] In other words and according to this variant, the print head comprises a building material inlet mouth, a bead extrusion nozzle and a metering pump configured to convey the building material from the inlet mouth to the extrusion nozzle, and this pump is controlled by the measurement of the width of the extruded bead.

[0044] According to another advantageous variant of the invention, said supply circuit comprises a booster pump for said supply line with construction material from the storage tank and this booster pump forms said regulating pump.

[0045] According to this advantageous variant, the regulating pump is formed by a booster pump arranged within the supply circuit of the print head and configured to convey the construction material from the storage tank to said supply line.

[0046] The invention also relates to a method for extruding beads of construction material for a robot for additive manufacturing of architectural structures comprising: a step of supplying construction material to a print head comprising a construction material inlet and an extrusion nozzle configured to form beads of construction material, from a construction material storage tank and a cementitious material flow rate control pump arranged between the storage tank and the extrusion nozzle, a step of moving said print head along a predetermined trajectory and a controlled speed, from upstream to downstream, a step of extruding beads of construction material by said print head, a step of measuring the width of the beads extruded upstream of the extrusion nozzle,from data acquired by three lasers oriented towards said extruded bead upstream of said extrusion nozzle, and arranged relative to each other in such a way that the projected light rays form a closed triangle surrounding said extrusion nozzle, a step of controlling the speed of movement of said print head and / or the flow rate of said regulating pump as a function of said measured bead width.,

[0047] The advantages and technical effects of an extrusion system according to the invention apply mutatis mutandis to a method according to the invention.

[0048] In particular, a method according to the invention makes it possible to control the speed setpoint for moving the print head and / or the control setpoint for the construction material regulation pump to the actual instantaneous measurement of the width of the extruded bead.

[0049] A method according to the invention is advantageously implemented by an extrusion system according to the invention and an extrusion system according to the invention advantageously implements a method according to the invention.

[0050] The invention also relates to an extrusion system, an additive manufacturing robot and an extrusion method characterized in combination by all or part of the features mentioned above or below.

[0051] List of figures

[0052] Other aims, characteristics and advantages of the invention will appear on reading the following description given solely for non-limiting purposes and which refers to the appended figures in which:

[0053] [Fig. 1] is a schematic view of an extrusion system according to one embodiment of the invention,

[0054] [Fig. 2] is a schematic view of a print head of a system according to one embodiment of the invention,

[0055] [Fig. 3] is a schematic top view of a bead extruded by an extrusion system according to an embodiment of the invention, showing the closed polygons formed by the lasers of the measuring device mounted on the print head,

[0056] [Fig. 4] is a schematic view of an extrusion process according to one embodiment of the invention,

[0057] [Fig. 5a] and [Fig. 5b] are schematic views illustrating the principle of trigonometric measurement of the width of an extruded bead from data from the sensors of the system according to the invention.

[0058] Detailed Description of an Embodiment of the Invention In the figures, the scales and proportions are not strictly respected for the purposes of illustration and clarity. Throughout the detailed description which follows with reference to the figures, unless otherwise indicated, each element of the extrusion system is described as it is arranged when the extrusion system is implemented in the context of the manufacture of an architectural structure by stacking layers of extruded cords.

[0059] Furthermore, identical, similar or analogous elements are designated by the same references in all figures.

[0060] An extrusion system according to the invention comprises, as shown in Figure 1, a storage tank 10 for a construction material, a print head 30 comprising a construction material inlet and a nozzle for extruding a bead of cementitious material, a circuit 20 for supplying construction material to the print head, arranged between the storage tank 10 and the print head 30, and a device 40 for measuring the width of the bead extruded downstream of the extrusion nozzle of the print head, this measuring device being carried by the print head.

[0061] Figure 1 also shows a robot 50 which carries the print head 30 and which is configured to move the print head along a predetermined path to enable the fabrication of an architectural structure 60 by adding successive layers of beads of building material extruded from the print head 30.

[0062] Throughout the following, the invention is described considering that the material used is a cementitious material, it being understood that any other viscous paste construction material as defined in the text can be used within the framework of this invention.

[0063] Each of the different organs of the system will now be described in detail, in particular in connection with figures 1 and 2.

[0064] Storage tank

[0065] The storage tank 10 is preferably a hopper comprising an upper opening 11 adapted to receive batches of cementitious materials and a lower outlet 12 connected to the supply circuit 20. The hopper may further comprise an agitator 13 comprising a shaft 14 carrying a plurality of lateral blades via axes perpendicular to the shaft 14, and a motor 16 for rotating the shaft 14. The motor 16 is for example an electric motor configured to be able to drive at low speed, for example at a speed of six revolutions per minute, the shaft 14 of the agitator 13. The use of a heat engine is of course possible without modifying the performance of the extrusion system according to the invention. The role of the agitator is to be able to maintain the cementitious material in the hopper in a quasi-constant rheological state before being conducted to the print head by the supply circuit 20.

[0066] The cementitious material used is, for example, a cement-based premix with fine particles, hydrated and fluidified.

[0067] Power supply circuit

[0068] The supply circuit 20 connects the storage tank 10 to the print head 30. This circuit comprises a pipe 21 connecting the outlet 12 of the storage tank 10 to an inlet 31 of the print head 30. The supply circuit 20 further comprises a booster pump 22. This booster pump 22 is for example an eccentric screw pump so as to be able to convey the cementitious material to the print head 30 while minimizing pulsations.

[0069] Print head

[0070] The print head 30 comprises, as schematically represented in FIG. 2, an inlet mouth 31 connected to the supply circuit 20 and a nozzle 34 for extruding cementitious material configured to form beads of cementitious material.

[0071] The print head further comprises a mixing chamber 35 arranged upstream of the extrusion nozzle 34. This mixing chamber 35 is equipped with a dynamic mixer adapted to be able to mix the cementitious material and any additives supplied by an additional additive device not shown in the figures.

[0072] This dynamic mixer comprises for example a shaft 37 extending longitudinally in the mixing enclosure 35 on which are mounted radial fingers 38 distributed along the shaft 37. The dynamic mixer also comprises a motor 39 configured to be able to drive the shaft 37 in rotation so as to be able to provide a homogeneous mixture of the cementitious material. This motor 39 can be an electric motor, a thermal engine, and generally all types of motors. According to the embodiment of the figures, the motor 39 is offset relative to the shaft 37. Of course, it is also possible to use a motor 39 not offset from the shaft 37.

[0073] The print head 30 also comprises an eccentric screw metering pump 51 configured to be able to convey the cementitious material from the inlet mouth 31 to the extrusion nozzle 34, passing through the mixing enclosure 35. Such a metering pump is for example an eccentric screw jacket pump. Of course, other pumps can be used without modifying the performance of the invention. As explained later, this metering pump forms, according to the embodiment of the figures, the regulating pump controlled by the measurement of the width of the extruded bead.

[0074] The extrusion nozzle 34 of the print head is preferably removable so as to be able to adapt the shape of the extrusion nozzle 34 to the part to be manufactured. In particular, the section of the extrusion nozzle 34 can be adapted to each type of part manufactured, or even changed during printing to modify the section of the beads of certain portions of the part manufactured. To do this, the extrusion nozzle comprises for example a threaded external wall which cooperates with a threaded internal portion of the wall of the print head delimiting the mixing enclosure 35. According to another variant, the extrusion nozzle comprises a threaded internal wall which cooperates with a threaded external portion of the wall of the print head.

[0075] The print head is moved by the robot along a predetermined path, from upstream to downstream.

[0076] Device for measuring the width of extruded cords

[0077] The device 40 for measuring the width of the extruded cords comprises, according to the embodiment of the figures, three lasers carried by a crown 52 secured to the print head. Each laser is configured to be able to project a light segment and deduce therefrom a measurement of the length of the material detected under this light beam. Such a laser is for example a laser marketed under the reference LLT3010-100 by the company Micro-Epsilon®. Of course, nothing prevents the use of other laser references for implementing the invention.

[0078] Such a laser allows the acquisition of a plurality of laser images (hereinafter referred to as "frames"). A frame contains a certain amount of information dependent on the resolution of the laser. The laser used has a resolution of 2048 points coded on 64 bytes. Each frame is composed of 4 bands of 16 bytes, each of which encodes different information.

[0079] In the case of the laser used, the X and Z position information is encoded by bytes 5 to 8 on each strip. The "X" corresponds to the position along the laser and the "Z" corresponds to the depth of the laser.

[0080] We can therefore retrieve the "X" and "Z" data on each frame, which can then be transformed into distance information by applying a decoding function. We therefore have a function which forms the laser profile and which associates a given Z with each X.

[0081] Since we know the distance in Z between the laser (mounted firmly on the print head) and the extruded bead, we can extract the threshold values ​​Xmin and Xmax which constitute the edges of the extruded bead. The difference makes it possible to obtain the length of the segment which intersects the bead.

[0082] This segment forms the width of the bead if the laser is oriented perpendicular to the bead. In practice, the laser often forms an angle with the bead that must be taken into account to deduce the bead width. The calculation principle is explained below, in connection with Figures 3, 5a and 5b.

[0083] If the measurement involves only one laser (as shown at position PA in Figure 3), the bead width l is obtained by the following trigonometric calculation: l = Im * sin(oc). where oc is the angle between the laser profile (which is known by knowing the print head displacement) and the extruded bead, and Im is the measurement of the laser segment provided by the laser obtained by following the methodology described previously. Figure 5a schematically illustrates this trigonometric calculation principle for calculating the extruded bead width from a single laser.

[0084] If the measurement involves two lasers (as shown at position PD in Figure 3, in the downward direction), the bead width l is obtained by the following trigonometric calculation: l = Iml. sin(a) + Zm2. sin(P) where Iml and lm2 are the segment measurements provided by the two lasers involved, and the angles oc and P are the angles between the laser profile of each laser (known by knowledge of the print head displacement) and the extruded bead. Figure 5b schematically illustrates this trigonometric calculation principle for calculating the extruded bead width from two lasers.

[0085] The lasers are arranged relative to each other in such a way that the projected light rays form a closed triangle that surrounds the axis of the extrusion nozzle.

[0086] Figure 3 schematically illustrates, in top view, a bead 62 extruded by a system according to the invention and the light rays projected by the lasers of the measuring device according to the embodiment of the figures. The nozzle of the print head is represented schematically by the reference circle 30 and the arrow inside the circle illustrates the orientation of the print head. The orientation of the print head does not necessarily correspond to the direction of movement of the print head. In particular, in Figure 3, it can be seen that the trajectory of the head, represented by the shape of the extrusion bead 62, does not modify the orientation of the print head.

[0087] In Figure 3, the print head is shown at four positions on the extrusion path of the bead 62, referenced respectively PA, PB, PC and PD.

[0088] The print head 30 comprises three lasers projecting the light rays illustrated by the references 41, 42 and 43 respectively. In the following, the projected light ray is assimilated to the laser having projected it. The lasers 41, 42, 43 are mounted on the print head 30 and arranged relative to each other and relative to the print head 30 in such a way that the projected light rays form a closed triangle. Of course, each light ray can extend beyond the point of intersection with the adjacent light rays. In the figures, only the closed triangle is shown for the purposes of illustration and clarity. The projection of the lasers 41, 42 and 43 is fixed relative to the orientation of the print head 30 since the lasers are mounted securely on the print head 30 by means of a plate 52 shown schematically in FIG. 2.

[0089] Thus, whatever the movement and orientation of the print head during extrusion, at least one of the lasers carried by the head is capable of measuring the width of the bead that has just been extruded, following the principles explained previously.

[0090] Thus, in Figure 3, if we consider that the head moves from the top of the figure to the bottom, that is to say that the head successively occupies the positions PA, PB, PC and PD, then the measurement of the width of the extruded bead 62, at the position PA, is derived from the laser 42. Indeed, this laser makes it possible to calculate the width of the bead which has just been extruded by the head 30, and arranged immediately upstream of the printing head, by applying the calculation principle explained previously (case where the measurement only involves a single laser).

[0091] The width measurement of the extruded bead 62 at position PB is derived from the laser 41 and the width measurement of the extruded bead 62 at position PC is derived from the laser 42 by applying the calculation principle explained previously (case where the measurement involves only one laser).

[0092] At position PD, the width of the extruded bead is derived from lasers 41 and 42 by applying the calculation principle explained previously (case where the measurement involves two lasers).

[0093] It can also be seen that if we consider that the head moves in the opposite direction, from the bottom of the figure to the top, that is to say that the head successively occupies the positions PD, PC, PB and PA, then in the position PD, the measurement is derived from the laser 43, in the position PC, the measurement is derived from the laser 41, in the position PB, the measurement is derived from the laser 43 and in the position PA, the measurement is derived from the laser 4L In each of these positions and according to this direction of movement, the calculation principle is that where the measurement involves only one laser.

[0094] The person skilled in the art understands that whatever the orientation and trajectory of the head, the invention always makes it possible to have one or two lasers which intersect the bead and therefore makes it possible to determine the width of the bead which has just been extruded by applying the trigonometric calculation principles explained previously.

[0095] This measurement is preferably used to adjust the displacement and flow rate of the cementitious material in the print head.

[0096] In particular, as indicated above, the geometry of the bead 62 depends mainly on the shape of the extrusion nozzle, the extrusion flow rate and the speed of movement of the print head. It can be assumed as a first approximation that for a circular nozzle, a bead extruded at a flow rate d has an oblong shape characterized by a height h and a width / , linked to each other by the formula d / v = l ~ Xh, where v represents the speed of movement of the print head.

[0097] The height h is imposed by the vertical displacement of the print head between a previous extrusion layer and the layer currently being extruded. Also, the d / v ratio conditions the width of the bead being extruded.

[0098] Thus, when the width of the bead is measured by the system according to the invention, a corrective measure can immediately be taken into account by adapting the speed of movement of the head and / or the flow rate of the material in the head (which corresponds to the flow rate of the metering pump 51 in the embodiment of the figures) to maintain the width of the bead within a predetermined value range, corresponding to the specifications of the part to be manufactured.

[0099] In other words, the invention makes it possible to control the speed of movement and flow rate of the cementitious material to the actual instantaneous measurement of the width of the extruded bead.

[0100] Figure 4 is a schematic view of a method for extruding beads of cementitious material for a robot for additive manufacturing of architectural structures according to the invention. Such a method comprises a first step E1 of supplying construction material, such as a cementitious material, to a head for printing beads of construction material from a construction material storage tank connected to the print head by a supply line equipped, for example, with a booster pump.

[0101] The method also includes a step E2 of moving the print head along a predetermined trajectory and a controlled speed which depends on the printing conditions.

[0102] The method also comprises a step E3 of extruding beads of construction material by the print head comprising an inlet mouth 31 of construction material, an extrusion nozzle 34 configured to form beads of construction material and a metering pump 51 configured to be able to convey the construction material from the inlet mouth 31 to the extrusion nozzle 34.

[0103] The method also includes a step E4 of measuring the width of the beads extruded upstream of the extrusion nozzle.

[0104] Finally, the method comprises a step E5 of controlling the speed of movement of the print head and / or the dosage of said dosage pump as a function of the width of the measured bead. In the embodiment described, the dosage pump of the print head forms the regulation pump of the system according to the invention.

[0105] The invention is not limited to the embodiments described. In particular, according to other embodiments, the robot may be a six-axis robot, mounted on rails or not, on a gantry or not. The robot may also be a cable robot or any type of robot whose positioning system, such as an articulated arm, can be controlled by computer.

[0106] Furthermore, the invention has been described by implementing a metering pump controlled by the measurement of the width of the bead. According to other embodiments, it is the booster pump which can be controlled by the measurement of the width of the bead. Similarly, a system can comprise a single metering or booster pump instead of the metering and booster pumps described in the embodiment of the figures.

[0107] A robot according to the invention can be used to manufacture all types of architectural parts. Such an architectural part can be a reinforcement part, a building, and generally, any part made of cementitious material. The architectural parts manufactured by the use of an extrusion system according to the invention can be of various scales. It can be a portion of a post, an entire post, a wall, a slab element, a building, street furniture, a sculpture, etc.

Claims

CLAIMS System for extruding building material cords for a robot (50) for additive manufacturing of architectural structures (60) comprising: a print head (30) for building material cords comprising a building material inlet mouth (31) and an extrusion nozzle (34) extending around an extrusion axis and configured to form an extruded cord (62) of building material, said print head (30) being intended to be moved by the additive manufacturing robot (50) along a predetermined trajectory, from upstream to downstream, to form an architectural structure (60) by stacking layers of said extruded cords (62), a circuit (20) for supplying building material to said print head (30) comprising a storage tank (10) for building material and a supply line (21) for building material connecting said storage tank (10) and said print head (30),a pump (22, 51) for regulating the flow of construction material circulating in said extrusion system arranged between said storage tank (10) and said extrusion nozzle (34), characterized in that it further comprises a device (40) for measuring without contact the width of the extruded bead (62) upstream of said extrusion nozzle (34), said measuring device (40) being carried by said print head (30) and comprising three lasers (41, 42, 43) associated with a unit for calculating the width of said bead from the data acquired by the lasers, said lasers being oriented towards said extruded bead, upstream of said extrusion nozzle, and arranged relative to each other in such a way that the projected light rays form a closed triangle surrounding said extrusion axis of the extrusion nozzle. System according to claim 1, characterized in that it further comprises a unit for controlling the speed and movement of said print head,(30) along a predetermined path, from upstream to downstream, and a control unit of said pump (22, 51) for regulating the flow of construction material, and in that said measuring device (40) for measuring the width of the extruded beads is configured to transmit said width measurement to said speed and displacement control unit and / or to said control unit of said regulation pump, so as to be able to control said speed of movement and / or said flow rate of the construction material to said measured width of the extruded bead upstream of the extrusion nozzle. System according to one of claims 1 or 2, characterized in that said print head comprises a metering pump (51) configured to be able to convey the construction material from said inlet mouth (31) to said extrusion nozzle (34), said metering pump (51) forming said regulation pump.System according to one of claims 1 to 3, characterized in that said supply circuit comprises a booster pump (22) for said supply pipe (21) of construction material from the storage tank (10), said booster pump (22) forming said regulation pump.Method for extruding building material cords for a robot for additive manufacturing of architectural structures comprising: a step (El) of supplying building material to a building material cord printing head comprising a building material inlet mouth and an extrusion nozzle extending around an extrusion axis and configured to form building material cords, from a building material storage tank and a cementitious material flow rate regulating pump arranged between the storage tank and the extrusion nozzle, a step (E2) of moving said printing head along a predetermined trajectory and a speed, from upstream to downstream, a step (E3) of extruding building material cords by said printing head,. a step (E4) of measuring the width of the beads extruded upstream of said extrusion nozzle, from data acquired by three lasers oriented towards said bead extruded upstream of said extrusion nozzle, and arranged relative to each other in such a way that the projected light rays form a closed triangle surrounding said extrusion axis of said extrusion nozzle, a step (E5) of controlling the speed of movement of said print head and / or the flow rate of said regulating pump as a function of said measured bead width.

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