High-capacity, improved precision additive manufacturing machine

Abstract

The present invention relates to an additive manufacturing machine (100) for large parts (8) with good manufacturing accuracy, said additive manufacturing machine (100) comprising a nozzle (6) for depositing beads (16), a moving platform (4), a pre-positioning system (18), and a final positioning system (5) cooperating with a spatial localization system (13) to position a reference point (Pr) of said moving platform (4) along a predefined target trajectory (Ti) with a final positioning accuracy (P3), said reference point (Pr) corresponding to a reference position of the nozzle (6) outlet orifice (20). The invention also relates to a method for implementing the additive manufacturing machine (100). Figure 1

Description

Title of the invention: High-capacity, improved precision additive manufacturing machine

[0001] The present invention relates to the general field of additive manufacturing machines which make it possible to manufacture parts of very diverse shapes by depositing a fluid printing material in successive layers, by means of a depositing nozzle, more simply called a "nozzle" in what follows.

[0002] In particular, the field of the invention relates to additive manufacturing machines for large parts produced by stacking extruded strands obtained by melting a wire or filament of a material that may be a polymer such as a thermoplastic or an elastomer. These additive manufacturing techniques are known as "filament melting" and may implement, for example, an FFF (Fused Filament Fabrication) method, an FDM (Fused Deposition Modeling) method, or an FGF (Fused Granulated Fabrication) method. Generally, the polymer wire is fed to a heating head that melts and pressurizes the polymer wire to allow its extrusion through the nozzle. Some additive manufacturing machines extrude a composite material comprising one or more molten polymers coating a reinforcing fiber.These composite materials make it possible to produce mechanical parts with higher mechanical properties.

[0003] Unlike some additive manufacturing machines with limited dimensional capabilities, filament fusion additive manufacturing machines make it possible to produce large parts that can be up to several meters in size, requiring means of moving the nozzle with large amplitudes of movement, such means of movement being, for example, Cartesian robots comprising rigid gantries or poly-articulated robots mounted on one or more axes of translation in order to increase the radius of action of said poly-articulated robot.

[0004] These robots with large ranges of motion allow for good positioning accuracy of the nozzle, but the increase in range of motion is not linear with the manufacturing cost, which increases sharply when such large ranges are desired.

[0005] The development of cable-driven parallel robots (CDPRs) has reduced the costs required to obtain additive manufacturing machines with means of moving the nozzle over long distances. These CDPRs are simple to design and implement, These systems generally include a rigid gantry, a mobile platform carrying work tools, several cables (usually at least eight to ensure the platform can move through at least six degrees of freedom), and motorized winches to extend or retract the cables to move the platform. The motorized winches are often equipped with encoders to track the cable length being extended and, consequently, the platform's position.

[0006] The simplicity and low cost of CDPR robots are generally achieved at the expense of the accuracy and repeatability of the mobile platform's positioning, and therefore of the working tool. The document "Large-scale 3D printing with cable-driven parallel robots," with Digital Object Identifier (DOI) 10.1007 / s41693-017-0008-0, describes an additive manufacturing machine using a CDPR robot and having an extrusion system as its working tool, mounted on the mobile platform. Such a machine makes it possible to produce large parts, but with low dimensional accuracy. Indeed, due to the large size of the additive manufacturing machine using the CDPR robot, long cables are required, and the deflection of these long cables becomes significant, making the nozzle positioning imprecise.The use of encoders on motorized winch motors does not correct the positioning error due to cable bending. To address this issue, tests were carried out to model cable bending or to increase cable tension, but these tests did not sufficiently improve nozzle positioning.

[0007] The objects assigned to the invention therefore aim to remedy the aforementioned drawbacks and to propose an additive manufacturing machine capable of producing large three-dimensional parts by depositing successive layers of cords of a malleable polymer, while ensuring good quality and precision of production.

[0008] The objects assigned to the invention are achieved by means of an additive manufacturing machine that produces a part by depositing beads of a printing material in successive layers in a manufacturing chamber, said additive manufacturing machine comprising: -a support platform designed to receive the first layer of printing and to support the part to be manufactured, -a mobile platform incorporating a dispensing device including a polymer filament feeding system, a heating head, a nozzle including a dispensing axis AA' and an outlet orifice, said mobile platform having a reference point Pr, -a working zone Zt in which the nozzle can be moved to deposit the beads of printing material, -an industrial programmable logic controller (PLC) enabling, on the one hand, the three-dimensional digitization of the part to be manufactured and, on the other hand, the definition of target trajectories Ti to be followed spatially by the nozzle to build said part to be manufactured, the additive manufacturing machine being characterized in that it comprises: -a spatial localization system having a localization accuracy PI, -a pre-positioning system comprising a cable-driven parallel robot cooperating with the spatial localization system to pre-position, according to at least three translational degrees of freedom, the reference point Pr along the target trajectory Ti with a pre-positioning accuracy P2, -a final positioning system, mounted on the mobile platform, allowing the nozzle to be moved along at least three degrees of freedom in relative translation with respect to the mobile platform, each movement along a degree of freedom being made along a direction from a central position to two opposite extreme positions, the outlet orifice of said nozzle being positioned on the reference point Pr when said nozzle is positioned in the central position of each of the three degrees of freedom, said final positioning system having a final positioning accuracy P3, said final positioning system cooperating with the spatial localization system to position the outlet orifice of the nozzle along the target trajectory Ti being realized with an absolute positioning accuracy Pa equal to the sum of the localization accuracy PI and the final positioning accuracy P3.

[0009] Essentially, the additive manufacturing machine of the invention makes it possible to produce large, three-dimensional parts with good manufacturing accuracy. The combination of the cable-driven parallel robot with the final positioning system and the spatial localization system allows the nozzle to be moved quickly and with a large range of motion while ensuring good quality and geometric accuracy of the manufactured part. The deviations in trajectory between an actual trajectory Tr and the target trajectory Ti are therefore minimal. The manufacturing cost of such an additive manufacturing machine remains low compared to Cartesian or multi-jointed robots with large ranges of motion combined with good positioning accuracy.

[0010] Advantageously, the cable parallel robot comprises a fixed tubular structure, at least eight cables and at least eight motorized winches, each of the at least eight cables being connected at a first end to one of the at least eight motorized winches, and at a second end to said mobile platform.

[0011] The use of a cable-driven parallel robot comprising at least eight cables allows the mobile platform to be moved according to six degrees of freedom, thus enabling the production of parts with complex shapes.

[0012] Preferably, the final positioning system allows: - to move the nozzle outlet in translation along three directions perpendicular to each other, - to rotate the nozzle's depositing axis AA' along three axes of rotation perpendicular to each other.

[0013] The three additional axes of rotation of the final positioning system make it possible to produce parts with complex geometries that are difficult to produce with actuators that only allow linear movements.

[0014] Advantageously, the final positioning accuracy P3 is at least twice and at most five times more accurate than the pre-positioning accuracy P2.

[0015] The use of a final positioning system having a final positioning accuracy P3 better than the pre-positioning accuracy P2 of the cable parallel robot makes it possible to manufacture a part of better dimensional quality without reducing the manufacturing productivity of the part.

[0016] Preferably, the spatial localization system is a vision system comprising at least two targets and at least two cameras sending information to the industrial programmable logic controller.

[0017] The use of cameras and targets makes it possible to define very precisely the positioning of the reference point Pr regardless of the position of the mobile platform.

[0018] Preferably, the targets are positioned on the mobile platform and the cameras are attached to fixed supports relative to the fixed tubular structure of the cable-parallel robot.

[0019] Advantageously, the targets are positioned on the nozzle and the cameras are attached to fixed supports relative to the fixed tubular structure of the cable-parallel robot.

[0020] The targets are generally light and compact elements, so that their placement on the mobile platform or on the nozzle makes it possible to lighten the moving elements, thus reducing their inertia and facilitating their movement at high speeds without having to reinforce the cable-driven parallel robot or the final positioning system.

[0021] Preferably, the final positioning system is a Stewart platform type hexapod, comprising two rigid structures and six rigid telescopic legs.

[0022] The Stewart platform type hexapod is a compact, lightweight and robust system, allowing the mobile platform to be lightened and the nozzle to be brought closer to already deposited beads while limiting the risks of interference with said Stewart platform.

[0023] Preferably, the final positioning system is a multi-articulated robot enabling a robust and precise industrial final positioning system, allowing the nozzle to be easily positioned in any position even in hard-to-reach areas.

[0024] The invention also relates to an additive manufacturing process implementing the additive printing machine described above and enabling the production of a part by the successive deposition of layers of filaments of a printing material, said additive manufacturing process being characterized by: - a first step a) using the industrial programmable logic controller to digitize the part to be manufactured and define target trajectories Ti to be followed by the nozzle to manufacture the part, - and by the following steps carried out simultaneously and continuously: b) activation of the deposit system, c) activation of the cable-driven parallel robot to cooperate with the spatial localization system to move and pre-position the reference point Pr of the mobile platform along the target trajectories Ti and with pre-positioning accuracy P2, d) activation of the final positioning system to cooperate with the spatial localization system to move the nozzle with final positioning accuracy P3 and position the nozzle outlet on the target trajectories Ti with absolute positioning accuracy Pa, e) when the nozzle outlet has traveled through all the target trajectories Ti, the part is finished and the dispensing device is deactivated.

[0025] Other objects, features and advantages of the invention will become apparent in more detail from the following description, as well as from the accompanying drawings, which are provided purely for illustrative purposes and are not intended to be limiting: - [Fig.l]: Overview and perspective view of an additive manufacturing machine according to the invention. - [Fig.2]: Front and detail view of a mobile platform, a final positioning system, a heating head and a nozzle. - [Fig.3]: Top view of a target trajectory Ti and an actual trajectory Tr of a nozzle during the deposition of a bead of printing material. - [Fig.4]: Simplified front view with representation of only the support plates and the nozzle and heating head assembly, [Fig.4] allowing to illustrate the positioning of the nozzle according to Cartesian and angular coordinates.

[0026] In what follows, for the sake of clarity, the horizontal direction and the vertical direction correspond to the natural orientation of figures 1 to 7. Similarly, the terms "top", "bottom", "lower", "upper" and their variants should be understood with reference to the vertical direction of the figures.

[0027] As can be seen in [Fig. 1], the additive manufacturing machine 100 of the invention makes it possible to produce a part 8, generally of large dimensions, by depositing beads 16 of a printing material in successive layers in a build chamber (not shown). By large dimensions, it is understood that a part 8 has dimensions of up to several meters.

[0028] The additive manufacturing machine 100 includes a support platform 9 for receiving the first printing layer and supporting the part 8 to be manufactured. The support platform 9 includes side edges and a top surface 17, said top surface 17 being, in general, rectangular or square in shape, and parallel to any horizontal XY plane.

[0029] As can be seen in [Fig. 1] and [Fig. 2], the additive manufacturing machine 100 also includes a mobile platform 4 carrying a deposition device 19 comprising a polymer filament feeding system 7, a heating head 14, a nozzle 6 comprising a deposition axis AA' and an outlet orifice 20, said mobile platform 4 having a reference point Pr,

[0030] The mobile platform 4 can be formed by a welded or bolted tubular assembly in the shape of a cubic parallelepiped. Other shapes and structures can be considered for the mobile platform 4, such as rectangular parallelepipeds made by assembling solid or perforated panels, glued or interlocked. As illustrated in [Fig. 2], the dispensing axis AA' of the nozzle 6 corresponds to an axis passing through the center of the nozzle 6's outlet orifice 20 and having a direction parallel to the extrusion direction of the printing material exiting the nozzle 6.

[0031] The polymer filament feeding system 7 mounted on the mobile platform 4 is partially shown in [Fig. 1] and [Fig. 2], illustrating only the arrival of the polymer filament 7 at the heating head 14. As is known to those skilled in the art, the polymer filament feeding system 7 may comprise a spool of polymer filament 7 with its unwinding system, and a filament traction and guidance system. The entire polymer filament feeding system 7 may be mounted on the mobile platform 4 or may be relocated to a fixed support relative to said mobile platform 4. When the feeding system is relocated, the traction and guidance system allows the polymer filament 7 to be conveyed to the heating head 14 regardless of the position of the mobile platform 4.

[0032] As is also well known to those skilled in the art, the heating head 14 includes a heating means for melting, pressurizing, and conveying the polymer to the nozzle 6 in order to extrude a bead 16 of molten polymer. The heating means may be, for example, an electric heater or a hot fluid circulation heater. Power may be supplied by batteries or by using flexible electrical cable channels that follow the movements of the mobile platform 4. Similarly, hot fluid circulation heating may be achieved using flexible hoses that follow the movements of the mobile platform 4.

[0033] The additive manufacturing machine 100 also includes a work area Zt in which the nozzle 6 can be moved to deposit the beads 16 of the printing material. The work area Zt can be of different shapes depending on the movement capabilities of the cable-driven parallel robot 1 and may, for example, be parallelepiped-shaped.

[0034] The additive manufacturing machine 100 further includes an industrial programmable logic controller 15 which allows, on the one hand, the three-dimensional digitization of the part 8 to be manufactured and, on the other hand, the definition of target trajectories Ti to be followed spatially by the nozzle 6 to construct said part 8 to be manufactured.

[0035] During digitization, the programmable logic controller (PLC) 15 will decompose the part 8 into a plurality of layers of predefined thicknesses corresponding approximately to the height of the beads 16 deposited by the dispensing nozzle 6. This same PLC 15, or another PLC 15, can also be used to control all the different actuators of the additive manufacturing machine 100.

[0036] In order to define the target trajectories Ti of the nozzle 6, the programmable logic controller 15 can, by way of example and as partially shown in [Fig. 4], define a Cartesian coordinate system Xi, Yi, Zi allowing the outlet orifice 20 of the nozzle 6 to be located in space within the working area Zt. In addition, a second angular coordinate system ai, [3i, yi] can also be used by the programmable logic controller 15 to define the orientation of the dispensing axis AA' of the nozzle 6 with respect to the upper surface 17 or with respect to the lateral edges of the support plate 9. The angles ai and [3i] can be angles indicating the orientation of the dispensing axis AA' of the nozzle 6 with respect to the upper surface 17, and the angle yi can correspond to the rotation of the nozzle 6 with respect to one of the lateral edges of the support plate 9.The angle yi is especially useful when the section of the nozzle 6 is not circular, but, for example, rectangular. The position corresponding to a value of zero for the coordinates Xi, Yi and Zi can be one of the corners of the support plate 9, the value of zero for the angles ai, [3i can correspond. to a vertical orientation of the deposit axis AA' of the nozzle 6 and the zero value of the angle yi can correspond to a parallel orientation of one of the edges of the outlet orifice 20 of a rectangular nozzle 6 with respect to one of the edges of the support plate 9. The spatial position according to the coordinates Xi, Yi, and Zi and the spatial orientation according to the angles ai, [3i, yi of the nozzle 6 are more simply called hereafter "the positioning" of the nozzle 6.

[0037] In general, the target trajectories Ti of the nozzle 6 are defined by establishing a succession of coordinates Xi, Yi, Zi, ai, [3i and yi] at time intervals. Depending on the desired accuracy for the target trajectories Ti, the time interval can be longer or shorter and can be, for example, between 50 and 200 ms.

[0038] The additive manufacturing machine 100 is characterized in that it comprises a spatial localization system 13, a pre-positioning system 18 and a final positioning system 5.

[0039] The spatial localization system 13 has a localization accuracy PI and may be, for example, a laser system comprising at least three lasers positioned on the mobile platform 4 or on the nozzle 6, a wireless system using, for example, radio frequency with a transmitter and a receiver, or a combination of several systems. The localization accuracy PI may be on the order of ±0.5 mm.

[0040] The pre-positioning system 18 includes a cable-driven parallel robot 1 cooperating with the spatial localization system 13 to pre-position, according to at least three translational degrees of freedom, the reference point Pr along the target trajectory Ti with a pre-positioning accuracy P2.

[0041] During the movement of the mobile platform 4, the spatial localization system 13 sends the position of the reference point Pr to the industrial programmable logic controller 15, said industrial programmable logic controller 15 acting on the cable-driven parallel robot 1 to move the mobile platform 4 until the reference point Pr is positioned along the target trajectory Ti with the pre-positioning accuracy P2. The pre-positioning of the reference point Pr of the nozzle 6 is thus carried out in a "closed loop".

[0042] The pre-positioning accuracy P2 depends on several parameters such as, for example, the dimensions of the work area Zt or the weight of the mobile platform 4. As an example, for an additive manufacturing machine 100 comprising a work area Zt having dimensions equal to 5 m and having a weight of 50kg, the pre-positioning accuracy P2 can be ±5mm.

[0043] The final positioning system 5 is mounted on the mobile platform 4 and allows the nozzle 6 to be moved along at least three degrees of freedom in relative translation with respect to the mobile platform 4, each movement along one degree of freedom occurring in a direction from a central position to two opposite extreme positions, the outlet orifice 20 of said nozzle 6 being positioned on the reference point Pr when said nozzle 6 is positioned in the central position of each of the three degrees of freedom, said final positioning system 5 having a final positioning accuracy P3, said final positioning system 5 cooperating with the spatial localization system 13 to position the outlet orifice 20 of the nozzle 6 according to the target trajectory Ti being realized with an absolute positioning accuracy Pa equal to the sum of the localization accuracy PI and the final positioning accuracy P3.

[0044] The spatial localization system 13 sends the position of the outlet orifice 20 of the nozzle 6 to the industrial programmable logic controller 15 which first determines the deviation between the position of the outlet orifice 20 and the target trajectory Ti before activating the final positioning system 5 to move the nozzle 6 with the final positioning accuracy P3 until the outlet orifice 20 of the nozzle 6 is positioned according to the target trajectory Ti with the absolute positioning accuracy Pa.

[0045] The final positioning accuracy P3 depends on various parameters, such as, for example, the type of actuators used or the weight of the nozzle 6 and the heating head 14. As an example, for an additive manufacturing machine 100 comprising a working area Zt having dimensions equal to 5 m and having a weight of 50kg, the final positioning accuracy P3 can be ±0.1mm.

[0046] In certain unclaimed embodiments, the final positioning system 5 includes a fourth or fifth linear actuator, enabling the production of complex parts 8. For example, a linear actuator can be added to linearly move the outlet orifice 20 of the nozzle 6 along a fourth axis.

[0047] In certain unclaimed embodiments, the pre-positioning system 18 does not cooperate with the spatial localization system 13. In these embodiments, the pre-positioning of the reference point Pr of the mobile platform 4 is carried out "in open loop", each desired position of the reference point Pr in the working area Zt corresponding to predefined cable lengths, said cable lengths being defined by prior tests, by simulation or self-learning.

[0048] By absolute positioning accuracy Pa, we mean the distance between the actual position of the nozzle outlet 20 of the nozzle 6 and the theoretical position targeted on the trajectory Ti when the final positioning system 5 has completed the final positioning action. For example, if the localization accuracy PI is equal to ±0.5 mm and if the final positioning accuracy P3 is equal to ±0.1 mm, then the absolute positioning accuracy Pa is equal to 0.6 mm.

[0049] The at least three actuators of the final positioning system 5 allow the outlet orifice 20 of the nozzle 6 to be moved over a distance that is greater than the value of the pre-positioning position in order to avoid obtaining an absolute positioning accuracy Pa greater than the sum of the localization accuracy PI and the final positioning accuracy P3.

[0050] In some embodiments, the cable-driven parallel robot 1 comprises a fixed tubular structure 12, at least eight cables 3 and at least eight motorized winches 2, each of the at least eight cables 3 being connected at a first end to one of the at least eight motorized winches 2, and at a second end to said mobile platform 4.

[0051] The fixed tubular structure 12 may, by way of example and as illustrated in [Fig. 1], comprise at least four vertical posts located at the four corners of the build platform. The height of the posts determines the working height of the additive manufacturing machine 100, which will generally be less than the height of the posts of the tubular structure. In order to stiffen the tubular structure, it may also include reinforcing elements, such as horizontal bars, braces, or gussets, thereby stiffening said tubular structure.

[0052] The presence of eight cables 3 and eight motorized winches 2 allows the mobile platform 4 to be moved and tilted through six degrees of freedom. The winding and / or unwinding of the eight cables 3 is done simultaneously and synchronously to move and orient the mobile platform 4 and to maintain each cable 3 under tension at all times, thus preventing unwanted movements of the mobile platform 4 when stationary or in motion.

[0053] Any other type of cable-driven parallel robot 1, comprising for example more than eight cables 3 or a different tubular structure, may also be suitable for the invention.

[0054] In certain embodiments, the final positioning system 5 allows: - moving the outlet orifice 20 of the nozzle 6 in translation along three directions perpendicular to each other, - moving the dispensing axis AA' of the nozzle 6 in rotation along three axes of rotation perpendicular to each other.

[0055] Preferably, the final positioning accuracy P3 is at least twice and at most five times more accurate than the pre-positioning accuracy P2.

[0056] Preferably, the spatial localization system 13 is a vision system comprising at least two targets 10 and at least two cameras 11 sending information to the industrial programmable logic controller.

[0057] In a known manner, the targets are light and small components, which may be reflective targets or wave-emitting modules.

[0058] Preferably, the targets 10 are positioned on the mobile platform 4 and the cameras 11 are attached to fixed supports relative to the fixed tubular structure 12 of the cable-driven parallel robot 1. In such an embodiment, the targets are positioned at a predetermined distance from the reference point Pr, said predetermined distance being known to the programmable logic controller (PLC) 15, which will take said predetermined distance into account to act accordingly on the cable-driven parallel robot 1 and position the reference point Pr along the target trajectory Ti with a pre-positioning accuracy of P2. Similarly, the PLC 15 takes into account the predetermined distance between the targets 10 and the nozzle 6's outlet 20 to act on the final positioning system 5 and position said nozzle 6's outlet 20 along the target trajectory Ti with a final positioning accuracy of P3.

[0059] Preferably, the targets 10 are positioned on the nozzle 6 and the cameras 11 are attached to supports fixed relative to the fixed tubular structure 12 of the cable-driven parallel robot 1. In such an embodiment, the programmable logic controller (PLC) 15 takes into account the distance between the targets 10 positioned on the nozzle 6 and the reference point Pr and uses this distance to act on the cable-driven parallel robot 1 and pre-position said reference point Pr along the trajectory Ti with a pre-positioning position P2. Similarly, the PLC 15 takes into account the distance between the targets 10 and the outlet 20 of the nozzle 6 to act on the final positioning system 5 and position said outlet 20 of the nozzle 6 along the target trajectory Ti with the final positioning accuracy P3.In such an embodiment, the positioning of the outlet orifice 20 of the nozzle 6 by the final positioning system is carried out in a "closed loop".

[0060] Preferably, and as shown in [Fig. 2], the final positioning system 5 is a Stewart 40 platform-type hexapod, comprising two rigid structures and six rigid telescopic legs. One of the two rigid structures is fixed to the mobile platform 4 or may be part of said mobile platform 4, and the other rigid structure supports the placement system. Each of the rigid telescopic legs comprises two ends articulated respectively to each rigid structure by means of a spherical joint. With such a Stewart 40 platform, it is possible, by changing the length of each rigid telescopic leg, to move the rigid structure supporting the placement system through six degrees of freedom. In general, the rigid telescopic legs are electric actuators comprising an electric motor and a worm gear system.Other types of cylinders can be considered, such as hydraulic or pneumatic cylinders.

[0061] Preferably, the final positioning system 5 is a multi-jointed robot, comprising at least three degrees of freedom. By way of example, multi-jointed robots having three degrees of freedom in translation and three degrees of freedom in rotation may be used. Preferably, small multi-jointed robots sizes will be used in order to minimize the size and weight of said multi-articulated robots.

[0062] The invention also relates to an additive manufacturing process implementing the additive manufacturing machine of the invention.

[0063] The additive manufacturing process makes it possible to produce a part 8 by the successive deposition of layers of cords 16 of a printing material, said additive manufacturing process being characterized by: - a first step a) using the industrial programmable logic controller 15 to digitize the part 8 to be manufactured and define target trajectories Ti to be followed by the nozzle 6 to manufacture the part 8, - and by the following steps carried out simultaneously and continuously: b) activation of the dispensing system 19, c) activation of the cable-driven parallel robot 1 to cooperate with the spatial localization system 13 to move and pre-position the reference point Pr of the mobile platform 4 along the target trajectories Ti and with the pre-positioning accuracy P2, d) activation of the final positioning system 5 to cooperate with the spatial localization system 13 to move the nozzle 6 with the final positioning accuracy P3 and position the outlet orifice 20 of the nozzle 6 along the target trajectories Ti with the absolute positioning accuracy Pa, e) when the nozzle 6 has traveled through all the target trajectories Ti, the part 8 is finished and the dispensing device 19 is deactivated.

[0064] As can be seen in [Fig. 3], the process of the invention makes it possible to deposit a bead 16 along an actual trajectory Tr close to the target trajectory Ti. For each theoretical position targeted on the target trajectory Ti, the distance between the actual position of the outlet orifice 20 and its theoretical position on said target trajectory Ti is never greater than the absolute positioning accuracy Pa, thus making it possible to produce parts 8 with very good geometric accuracy.

Claims

1. Demands Additive manufacturing machine (100) for producing a part (8) by depositing successive layers of printing material (16) in a manufacturing chamber, said additive manufacturing machine (100) comprising: -a support platform (9) intended to receive the first layer of printing and to support the part (8) to be manufactured, -a mobile platform (4) carrying a dispensing device (19) comprising a polymer filament feeding system (7), a heating head (14), a nozzle (6) comprising a dispensing axis (AA') and an outlet orifice (20), said mobile platform (4) having a reference point (Pr), -a working area (Zt) in which the nozzle (6) can be moved to deposit the beads (16) of printing material, -an industrial programmable logic controller (15) enabling, on the one hand, the three-dimensional digitization of the part (8) to be manufactured and, on the other hand, the definition of target trajectories (Ti) to be followed spatially by the nozzle (6) to construct said part (8) to be manufactured, the additive manufacturing machine (100) being characterized in that it comprises: -a spatial localization system (13) having a localization accuracy (PI), - a pre-positioning system (18) comprising a cable-driven parallel robot (1) cooperating with the spatial localization system (13) to pre-position, with at least three translational degrees of freedom, the reference point (Pr) along the target trajectory (Ti) with a pre-positioning accuracy (P2), - a final positioning system (5), mounted on the mobile platform (4), enabling the nozzle (6) to be moved with at least three degrees of freedom in relative translation with respect to the mobile platform (4), each movement with one degree of freedom occurring in a direction from a central position to two opposite extreme positions, the outlet orifice (20) of said nozzle (6) being positioned on the reference point (Pr) when said nozzle (6) is positioned in the central position of each of the three degrees of freedom, said final positioning system (5) having a final positioning accuracy (P3), said positioning system. final (5) cooperating with the spatial localization system (13) to position the outlet orifice (20) of the nozzle (6) according to the target trajectory (Ti) being realized with an absolute positioning accuracy (Pa) equal to the sum of the localization accuracy (PI) and the final positioning accuracy (P3).

2. Additive manufacturing machine (100) according to claim 1, wherein the cable parallel robot (1) comprises a fixed tubular structure (12), at least eight cables (3) and at least eight motorized winches (2), each of the at least eight cables (3) being connected at a first end to one of the at least eight motorized winches (2), and at a second end to said mobile platform (4).

3. Additive manufacturing machine (100) according to any one of claims 1 or 2, wherein the final positioning system (5) allows: - translational movement of the outlet orifice (20) of the nozzle (6) along three perpendicular directions, - rotational movement of the deposit axis AA' of the nozzle (6) along three perpendicular axes of rotation.

4. Additive manufacturing machine (100) according to any one of claims 1 to 3, wherein the final positioning accuracy (P3) is at least two times and at most five times more accurate than the pre-positioning accuracy (P2).

5. Additive manufacturing machine (100) according to any one of claims 1 to 4, wherein the spatial localization system (13) is a vision system comprising at least two targets (10) and at least two cameras (11) sending information to the industrial programmable logic controller (15).

6. Additive manufacturing machine (100) according to claim 5, wherein the targets (10) are positioned on the moving platform (4) and the cameras (11) are hung on fixed supports relative to the fixed tubular structure (12) of the cable-parallel robot (1).

7. Additive manufacturing machine (100) according to claim 5, wherein the targets (10) are positioned on the nozzle (6) and the cameras (11) are hung on supports fixed relative to the fixed tubular structure (12) of the cable-parallel robot (1).

8. Additive manufacturing machine (100) according to any one of claims 1 to 7, wherein the final positioning system (5) is a Stewart platform type hexapod (40), comprising two rigid structures and six rigid telescopic legs.

9. Additive manufacturing machine (100) according to any one of claims 1 to 7, wherein the final positioning system (5) is a multi-jointed robot.

10. An additive manufacturing process employing the additive printing machine (100) according to any one of claims 1 to 9 and enabling the production of a part (8) by the successive deposition of layers of cords (16) of a printing material, said additive manufacturing process being characterized by: - ​​a first step a) of using the industrial programmable logic controller (15) to digitize the part (8) to be manufactured and define target trajectories (Ti) to be followed by the nozzle (6) to manufacture the part (8), - and by the following steps carried out simultaneously and continuously: b) activation of the deposition system (19), c) activation of the cable-driven parallel robot (1) to cooperate with the spatial localization system 13 to move and pre-position the reference point (Pr) of the mobile platform (4) along the target trajectories (Ti) and with the pre-positioning accuracy (P2),d) activation of the final positioning system (5) to cooperate with the spatial localization system (13) to move the nozzle (6) with the final positioning accuracy (P3) and position the outlet orifice (20) of the nozzle (6) along the target trajectories (Ti) with the absolute positioning accuracy (Pa), e) when the nozzle (6) has followed all the target trajectories (Ti), the part (8) is finished and the dispensing device (19) is deactivated.

Images