Installation for cutting, welding, cladding or metal additive manufacturing by laser beam comprising an inerting chamber housing a robot terminal effector and a rotating platform of a two-axis positioner.

Abstract

A laser beam-based metal cutting, welding, cladding, or additive manufacturing installation comprising an inert gas chamber housing a robot end effector and a rotating platform of a two-axis positioner. The invention relates to a laser beam-based cutting, welding, cladding, or additive manufacturing installation (1), comprising robotics with a two-axis positioner while ensuring inert gas within the inert gas chamber in which the laser beam is used for manufacturing, with very low O2 and H2O levels. Figure for the abstract: Fig. 6

Description

Title of the invention: Installation for cutting, welding, cladding or additive manufacturing of metal by laser beam comprising an inerting chamber housing a terminal robot effector and a rotating platform of a two-axis positioner. technical field

[0001] The present invention relates mainly to the field of metal additive manufacturing.

[0002] More particularly, the invention relates to an improvement by robotisation of an additive manufacturing process implementing a laser beam within an inerting chamber.

[0003] Although described in particular with reference to a wire laser metal additive manufacturing process, known as WLAM for "Wire Laser Additive Manufacturing", the invention relates more generally to any process of cutting, welding, and metal additive manufacturing by laser beam in all industrial, engineering and parts manufacturing fields, particularly in the nuclear field. Previous technique

[0004] The WLAM process is a relatively recent process currently under development. This process allows for the design of parts or shapes using design software. A part is produced layer by layer to obtain the thinnest possible layers. The layers are then deposited successively by the additive manufacturing system. Thus, the WLAM process is comparable to traditional 3D printing, but with the use of a metal filament melted by a laser instead of plastic filament melted by a nozzle.

[0005] Compared to selective laser melting (SLM) and laser powder deposition (LMD), a WLAM process offers numerous advantages, notably its suitability for designing large parts and its ability to meet high production rates. The laser uses 1 to 2 mm spots, producing much more localized heat. A WLAM process thus makes it possible to build parts that could not be produced using wire arc additive manufacturing (WAAM).

[0006] In addition, the use of wire makes it possible to guarantee a material yield of 100%.

[0007] Furthermore, in a WLAM process, the risks associated with the use of a powder are eliminated. A WLAM process thus allows for a significant reduction in costs related to personal protective equipment and the health monitoring of operators.

[0008] Despite all the aforementioned advantages, the level of technological maturity of a WLAM process is lower than for the WAAM process.

[0009] In general, laser-based metal welding and additive manufacturing processes differ mainly from arc processes such as TIG welding, an Anglo-Saxon acronym for "Tungsten Inert Gas" or MIG, an Anglo-Saxon acronym for "Metal Inert Gas", in that they are carried out at higher welding speeds, higher power densities and higher melting temperatures.

[0010] This implies significant temperature gradients around the molten pool, which, by convection, draws contaminated gas around the molten pool. This generates impurities that impair the technical performance of the parts produced: appearance of cracks, crevices, bubbles, impurities, etc.

[0011] In particular, it is observed in the case of a WLAM process that the solutions usually employed for inerting do not limit the defects mentioned above. It should be noted here that inerting involves the use of inert gases such as argon, nitrogen, or helium. These inert gases can ensure the quality of the parts produced by protecting the molten materials during manufacturing. It also allows for control of the atmosphere during the additive manufacturing process.

[0012] Current inerting methods require spraying very large quantities of gas for mixed results. Furthermore, the inert gas (argon, nitrogen) used is lost as it disperses into the atmosphere.

[0013] Furthermore, the quality criteria required in certain application areas, such as low-carbon energy (nuclear or otherwise), require the absence of defects in the manufactured parts, sometimes made of special alloys. This implies inerting near the molten pool with very low O2 and H2O concentrations, typically below 10 ppm.

[0014] However, to date, these values ​​can only be obtained in a hermetically sealed inerting chamber which is rigid, that is to say with walls which delimit it which are rigid.

[0015] Figure 1 shows such a rigid enclosure 10, according to the prior art, generally rectangular in shape: it is delimited by four lateral walls 11, 12, 13, 14, a lower wall 15, and an upper wall 16. To allow the enclosure to be moved easily, it can be fitted with casters 17. Portholes 18 are intended to hold gloves (not shown) for handling parts, tools, and fabrications, and to allow maintenance to be carried out on the head of the machine. Additive manufacturing. The manufactured parts can be evacuated, if their size allows, through an airlock, which is the function of the part that "protrudes" to the outside.

[0016] Furthermore, robotization of cutting, welding, cladding or laser additive manufacturing facilities would ensure large movements in three dimensions and would thus allow the rapid production of finished volumetric metal parts with complex geometries, in particular parts with elliptical shapes of revolution or with added functions to cylindrical parts.

[0017] Inerting enclosures containing a robot are known. The inerting volume is then significantly larger, making the inerting of the enclosure longer and more expensive.

[0018] There is therefore a need to improve cutting, welding, cladding or additive manufacturing installations using a laser beam, in order to robotize them while making them compatible with implementation in an inerting chamber, with very low values ​​of O2 and H2O, typically less than 10 ppm which make it possible to increase the quality of the melting baths, to increase the mechanical resistance of the manufactured parts in order to best comply with the standards in force.

[0019] The aim of the invention is to meet at least part of this need. Description of the invention

[0020] To this end, the invention relates, in one of its aspects, to a laser beam cutting, welding, cladding or additive manufacturing installation, comprising

[0021] - an inerting enclosure, under an inert atmosphere, delimited by at least one wall rigid and a first and a second flexible sealing skirts each fixed in a watertight manner to at least one rigid wall;

[0022] - a robot terminal effector comprising a support, at least a part, of preferably its head, of at least one laser suitable for emitting a beam for cutting, welding, cladding or additive manufacturing and at least one watertight fixing flange, fixed or made entirely with the support and on which the first flexible sealing skirt is fixed in a watertight manner;

[0023] - a robot to which the robot terminal effector is attached, the robot being adapted for allow movement of the terminal effector within the enclosure, along one and / or the other of the three orthogonal directions (X, Y, Z);

[0024] - a two-axis platform(s) positioner, one of which is an axis of rotation around a (Z) of the three directions and a pivot axis around another (Z) of the three directions, to respectively rotate and pivot, within the enclosure, at least the upper plate around which the second flexible sealing skirt is fixed in a watertight manner, the upper plate forming a support for a part to be made by cutting, welding or additive manufacturing.

[0025] The inerting gas to be injected can be argon or nitrogen.

[0026] By "two-axis positioner" is meant the usual meaning of the technology, namely A self-contained motorized device, equipped with a rotating axis and a tilting axis, allows a part to be positioned in space. In the context of this invention, the operation of the two-axis positioner is advantageously controlled by the robot and the laser supported by the robot's end effector.

[0027] According to an advantageous embodiment, the enclosure comprises five rigid walls delimiting a right parallelepiped with the exception of the upper opening to which the first flexible skirt is attached in a watertight manner.

[0028] Advantageously, the robot is a six-axis articulated arm robot.

[0029] According to an advantageous embodiment, the positioner comprises:

[0030] - two rotating platforms, the upper platform and a lower platform being fixed together one from the other and fixed on the axis of rotation,

[0031] - at least one sealing joint between the two rotating plates defining a space waterproof

[0032] - a cooling plate, mounted in the sealed space and in which a fluid Heat transfer fluid can circulate in such a way as to cool the upper tray.

[0033] Such an assembly not only ensures the rotation of the part to be produced on itself but also the efficient evacuation of heat through the base of the positioner.

[0034] Indeed, laser additive manufacturing cycles generate very high temperatures in the parts, especially since they can be long, typically from one to several tens of hours. The hermetically sealed inert gas chamber confines the heat resulting from the melting of the materials to produce the parts, typically between 600 and 800°C. Thus, ensuring efficient cooling as close as possible to the upper platform that supports the part provides optimal thermal protection for the positioner components.

[0035] According to an advantageous embodiment, the positioner includes a pivoting body, fixed on the pivot axis and on which the upper plate is mounted for rotation.

[0036] According to an advantageous configuration, the lower rotating plate is mounted in rotation with contact with the pivoting body.

[0037] Advantageously, the positioner includes a locking pin to limit the pivoting of the upper plate, preferably at a maximum angle of + / - 20° to the horizontal. Thus, the locking pin keeps fixed the part on which the heat transfer fluid connections are installed.

[0038] According to an advantageous embodiment, the sealed fixing flange is housed in the less a sealed passage for laser power cable(s) or fiber(s), electrical power supply, fluid supply, including inerting gas, control cable(s) and / or instrumentation cable(s).

[0039] According to this variant, the sealed fixing flange also houses a sealed passage for a wire feeder to be melted by the laser for welding or additive manufacturing, the feeder being fixed to the support of the terminal effector.

[0040] Preferably, the sealing fixing flange is generally circular in shape, the periphery of which is sealed to the first flexible skirt.

[0041] Preferably, the laser is supported so that the axis of the beam it emits is centered on the center of the sealed mounting flange.

[0042] According to another advantageous embodiment, the installation includes at least one control unit for controlling the laser, the supply of the inerting gas and the movement of the robot and thereby of the terminal effector in the enclosure.

[0043] In an advantageous configuration, the seal between the first flexible skirt and the rigid wall(s) on the one hand, and the sealed fixing flange on the other hand, is such that the O2 and H2O values ​​are less than 10 ppm within the inerting chamber.

[0044] State-of-the-art laser-based cutting, welding and additive manufacturing processes make it possible to achieve high working speeds at high temperatures.

[0045] On the other hand, it has been observed that these processes generate more or less pollution, in particular dust(s) and / or smoke(s) from the melting bath generated by the laser, depending on the materials melted.

[0046] The inventors carried out thermodynamic analyses of inerting gas which showed that the very hot flows are violently disturbed and do not perform at their best what they are dedicated to, which deteriorates the quality of the inerting, and is therefore likely to cause defects during manufacturing.

[0047] However, the quality criteria required in certain fields require the absence of defects in the parts produced, sometimes manufactured in special alloys.

[0048] This necessarily implies that the production of these parts is carried out with inerting close to the melting bath with very low values ​​of O2 and H2O, typically less than 10 ppm.

[0049] To date, these values ​​can only be obtained in a rigid hermetically sealed inerting chamber.

[0050] Furthermore, the robotisation of current laser welding and additive manufacturing installations guarantees large movements in three dimensions and thus makes it possible to quickly produce finished volumetric metal parts with complex geometries.

[0051] The invention essentially consists of integrating a robotic system with a two-axis positioner into an installation while ensuring inerting within the enclosure

[0052]

[0053]

[0054]

[0055]

[0056] inerting in which the laser beam is implemented for manufacturing, with very low values ​​of O2 and H2O. The invention has numerous advantages, including: - the ability to move a laser cutting, welding, cladding or laser additive manufacturing head in the three directions X, Y, Z, while ensuring the sealing of the entire inerting enclosure and therefore constant inerting; - the possibility of producing large specific parts and / or complex three-dimensional shapes, including elliptical shapes of revolution or with added functions on cylindrical shapes, thanks to the two-axis positioner; - the possibility of exiting the manufactured parts through one of the airlocks via a rigid wall of the enclosure, thus allowing large volumes of gas to be recycled into the latter; - an improvement in the quality of welds and parts produced with laser cutting, or laser beam welding and laser metal additive manufacturing processes; - ease of use and adaptability to multiple processes with all types of industrial robots available, by standardizing all parts, flanges, seals, mechanisms that may be necessary for the operation of an installation according to the invention; - quick and easy disassembly, typically around 15 minutes, in the case of a change of environment, tools, or simply for changing the flexible sealing skirt in case of damage. This advantage is crucial for the industry, which is constrained by high capital expenditure costs; The potential applications of the described invention are that its installation can be carried out on all types of initially rigid hermetic enclosures / inerting chambers. All industrial applications of laser welding and additive manufacturing are concerned, particularly nuclear, aeronautical, naval, and automotive. Other advantages and features of the invention will become clearer upon reading the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures. Brief description of the drawings [Fig.1] [Fig.1] is a perspective view of a hermetically sealed inerting enclosure according to the state of the art.

[0057] [Fig.2] [Fig.2] is a perspective view of an additive manufacturing installation metallic laser, in a hermetically sealed inerting chamber and articulated arm robot according to the invention.

[0058] [Fig.3] [Fig.3] is a partial cross-sectional view of an installation according to the [Fig.2],

[0059] [Fig.4A], [Fig.4B] Figures 4A and 4B are perspective views of an effector robot terminal of the installation according to figures 2 and 3.

[0060] [Fig.5] [Fig.5] reproduces [Fig.2], without the presence of the upper wall of the enclosure and the sealing skirt with the outside.

[0061] [Fig. 6] [Fig. 6] is a perspective view of an additive manufacturing installation laser-cut metal, with a hermetically sealed inerting chamber, articulated arm robot and two-axis positioner according to the invention.

[0062] [Fig.7] [Fig.7] is another perspective view of the installation according to [Fig.6].

[0063] [Fig.8] [Fig.8] is a perspective view of an installation according to [Fig.6] or [Fig.7], without the presence of the inerting enclosure.

[0064] [Fig.9] [Fig.9] is a perspective view of a conforming two-axis positioner to the invention.

[0065] [Fig.1OA], [Fig.1OB], [Fig.1OC], Figures 10A, 10B, 10C are perspective views of a two-axis positioner according to the invention, according to different pivots of the workpiece support plate.

[0066] [Fig. 11] [Fig. 11] is a cross-sectional view of a two-axis positioner according to the invention, taken at the rotating part of the positioner. Detailed description

[0067] Throughout this application, the terms "lower", "upper", "below" and "above" are to be understood by reference to an inerting enclosure of an installation according to the invention, as it is in horizontal operating configuration.

[0068] For the sake of clarity, the same element according to the state of the art and according to the invention is designated by the same numerical reference.

[0069] Fig. 1 has already been described in the preamble. It will therefore not be detailed below.

[0070] Figures 2 and 3 show a laser-based metal additive manufacturing installation 1 according to the invention.

[0071] This installation first comprises an inerting chamber 10, under an inert atmosphere, housing a support, not shown, for a part to be produced by additive manufacturing. The inert atmosphere can be controlled by means of an oxygen sensor and advantageously with water. The temperature inside the chamber can be controlled by means of a temperature sensor. Advantageously, the humidity inside the chamber can be controlled by means of an H2O sensor.

[0072] The inerting enclosure 10 comprises five rigid walls 11, 12, 13, 14, 15 delimiting a right parallelepiped except for the upper opening to which is fixed in a sealed manner, the periphery 20 of a flexible sealing skirt 2.

[0073] The central perforated part 21 of the sealing skirt 2 is fixed in a hermetic manner to a robot effector 3. More specifically, the fixing of this central perforated part 21 is made on a hermetic fixing flange 30 of the terminal effector 3, which is generally circular in shape.

[0074] The seal between the flexible skirt 2 and the rigid walls 11, on the one hand, and the sealed fixing flange on the other hand, is such that the values ​​of O2 and H2O are less than 10 ppm within the inerting enclosure.

[0075] The flexible skirt 2 withstands high temperatures while ensuring the inerting chamber remains sealed. The skirt 2 may be made of a flexible polymer to provide sufficient degrees of freedom for the robot arm so that it can position the end effector 3 at any location inside the inerting chamber. The seals between the skirt 2 and the rigid part of the chamber, as well as between the skirt 2 and the end effector 3, are preferably made of nitrile.

[0076] This robot effector 3 includes a support 31 for the head of a laser 5 adapted to emit a beam for cutting, welding or additive manufacturing, and fixed or made entirely with the mounting flange 30.

[0077] A robot 4 with an articulated arm 40, preferably with six axes, is arranged with its base 41 near the inerting enclosure 10.

[0078] The terminal effector 3 is fixed to the end wrist 42 of the robot 4.

[0079] Thus, the robot 4 allows movement of the terminal effector 3, and therefore of the laser head 5, along one or more of the three orthogonal directions (X, Y, Z) within the enclosure. The flexible skirt 2, as fixed, deforms while ensuring a seal during the movements of the robot 4 and the effector 3 attached to it.

[0080] The terminal effector 3 is shown in more detail in figures 4A and 4B.

[0081] The support 31 incorporates a fixing flange 32 to the end handle 42 of the robot.

[0082] The watertight fixing flange 30 to the skirt 2 houses a watertight passage 33 for cable(s) or laser feed fiber(s), power supply, fluid supply (including inerting gas), control and / or instrumentation cable(s). This sealed flange 30 can be a standard, standard flange. The sealed flange 30 includes a set of sealed cable passages allowing all the elements essential to the proper functioning of the terminal effector 3 to be brought to it, such as: optical fiber, feed wire, gas supplies, etc. This flange also allows sensors to be brought to the terminal effector for monitoring the ambient conditions of the inerting chamber, such as... O2 and H2O sensors. The watertight cable passage33 can allow the passage of cables for instrumentation such as thermal sensors.

[0083] This sealed fixing flange 30 can also accommodate a sealed passage 35 of a wire feeder 6 to be melted by the laser for welding or additive manufacturing, the feeder being fixed to the support 31 of the terminal effector 3.

[0084] The laser source 5 is controlled by an emission signal sent from a control bay on the robot to the laser source. Gas management in the head is handled by an upstream control box, which is not shown.

[0085] The laser beam 5 is supported by the support so that the axis of the beam it emits is centered on the center of the sealed fixing flange 30.

[0086] In addition, one or more instrumentation supports 36, for example O2 and / or H2O or temperature and / or pressure sensors, can be fixed in the lower part of the support 31 to instrument the interior of the inerting enclosure 10. Generally, the supports 36 can be intended to receive instrumentation, such as cameras in the visible and infrared ranges, pyrometers, a thermal camera, etc. These supports 36 are preferably removable and can be removed manually, without tools, from the terminal effector 3.

[0087] Figures 6 to 7 show the integration of a two-axis positioner 7 in the rigid lower wall 15 of the inerting enclosure. One of the two axes is a rotation axis around the Z direction and the other a pivoting axis around another (Z) of the three directions, to respectively rotate and pivot, inside the enclosure, at least the upper plate around which the second flexible sealing skirt is fixed in a hermetic manner, the upper plate forming a support for a part to be produced by cutting, welding, cladding or additive manufacturing.

[0088] This positioner 7 includes an upper plate 70 forming a support for a part to be produced by cutting, welding, cladding or additive manufacturing by the laser 5.

[0089] The upper plate 70 is mounted to rotate on itself and fixed to a body 72 pivoting relative to the base 71 of the positioner 71.

[0090] A flexible sealing skirt 8 ensures sealing between the upper rotating plate 70 and the rigid lower wall 15 of the inerting enclosure 10.

[0091] More specifically, the periphery 80 of the flexible sealing skirt 8 is fixed in a watertight manner on the rigid lower wall 15 while the central perforated part 81 of the skirt 8 is fixed in a watertight manner around the rotating plate 70 of the positioner 7.

[0092] The seal between the flexible skirt 8 and the rigid wall 15 on the one hand, and around the lower rotating plate 70 on the other hand, is such that the values ​​in O2 and H2O are less than 10 ppm within the inerting enclosure.

[0093] Like the flexible skirt 2, the flexible skirt 8 resists high temperatures by ensuring the sealing of the inerting enclosure.

[0094] The fixing of the flexible, watertight skirt 8 around the upper rotating plate 70 of the positioner can be ensured by constituting a pre-assembled sub-assembly before its mounting in the inerting enclosure, as shown in [Fig.9].

[0095] The upper rotating plate 70 can take different tilt / pivot positions, for example horizontally ([Fig.1OA]), at +20° relative to the horizontal ([Fig.1OB]), or at -20° relative to the horizontal ([Fig.1OC]).

[0096] Fig. 11 shows an advantageous embodiment of the positioner 7 according to the invention.

[0097] The upper plate 70 and a lower plate 73 are fixed together and attached to the axis of rotation. Preferably, the lower rotating plate 73 is mounted to rotate in contact with a pivoting body 72 (ring), fixed to the axis of rotation.

[0098] The upper plate 70 and the lower plate 73, which connects with the 2-axis positioner, can rotate freely by being driven by the 2-axis positioner, without the body 72 on which the connections are installed rotating.

[0099] At least one sealing gasket 74, preferably two, arranged at the periphery, defines a sealed space between the two rotating plates 70, 73.

[0100] A cooling tray 75 is mounted in the sealed space. Inside this tray 75, a heat transfer fluid can circulate so as to cool the upper tray 70.

[0101] A locking pin 77, arranged at the periphery, allows the pivoting of the body 72 to be blocked relative to the base 71 of the positioner.

[0102] The installation 1 which has just been described makes it possible to produce large and / or complex shaped parts, in particular three-dimensional, such as elliptical shapes of revolution, in an inert environment with very low values ​​of O2 and / or H2O, which guarantees the quality of the melting bath by the laser.

[0103] The invention is not limited to the examples just described; in particular, features of the illustrated examples can be combined in unillustrated variants.

[0104] Other variants and embodiments may be envisaged without departing from the scope of the invention.

[0105] For example, if in the illustrated example the robot implemented is an articulated arm robot, other types of robot can be considered, such as a Cartesian robot.

[0106] Also, if in the illustrated example the inerting enclosure is in the shape of a right parallelepiped, any other rigid shape can be considered which allows a tight fixing of a flexible skirt which ensures the sealing interface with the end of a robot and guarantees an inert environment with very low values ​​of O2 and / or H2O.

Claims

Demands

1. Installation (1) for laser beam cutting, welding, cladding or additive manufacturing, comprising: - an inerting enclosure, under an inert atmosphere, delimited by at least one rigid wall and a first and a second flexible sealing skirt, each fixed hermetically to at least one rigid wall; - a robot end effector comprising a support, at least a part, preferably its head, of at least one laser adapted to emit a cutting, welding, cladding or additive manufacturing beam and at least one sealed mounting flange, fixed or made entirely with the support and to which the first flexible sealing skirt is fixed hermetically; - a robot to which the robot end effector is fixed, the robot being adapted to allow movement of the end effector inside the enclosure, in one and / or another of the three orthogonal directions (X, Y, Z);- a two-axis platform positioner(s), one axis of rotation around one (Z) of the three directions and one axis of pivoting around another (Z) of the three directions, to respectively rotate and pivot, inside the enclosure, at least the upper platform around which the second flexible sealing skirt is fixed in a watertight manner, the upper platform forming a support for a part to be produced by cutting, welding or additive manufacturing.;

2. Installation (1) according to claim 1, the enclosure comprising five rigid walls delimiting a right parallelepiped except for the upper opening to which the first flexible skirt is fixed in a sealed manner.

3. Installation (1) according to claim 1 or 2, the robot being a six-axis articulated arm robot.

4. Installation (1) according to any one of the preceding claims, the positioner comprising a locking pin to limit the pivoting of the The upper shelf should preferably be at an angle of no more than + / - 20° to the horizontal.

5. Installation (1) according to any one of the preceding claims, the sealed fixing flange housing at least one sealed passage for laser power cable(s) or fibre(s), power supply, fluid supply, including inerting gas, control cable(s) and / or instrumentation cable(s).

6. Installation (1) according to claim 5, the sealed fixing flange further housing a sealed passage for a wire feeder to be melted by the laser for welding or additive manufacturing, the feeder being fixed to the support of the terminal effector.

7. Installation (1) according to any one of the preceding claims, the sealing fixing flange being generally circular in shape, the periphery of which is sealed to the flexible skirt.

8. Installation (1) according to claim 7, the laser being supported so that the axis of the beam it emits is centered on the center of the sealed mounting flange.

9. Installation (1) according to any one of the preceding claims, comprising at least one control unit for controlling the laser, the supply of the inerting gas and the movement of the robot and thereby of the terminal effector in the enclosure.

10. Installation (1) according to any one of the preceding claims, the seal between the first flexible skirt and the rigid wall(s) on the one hand, and the sealed fixing flange on the other hand being such that the values ​​in O2 and H2O are less than 10 ppm within the inerting enclosure.

11. Use of the installation (1) according to any one of the preceding claims, for the production by laser cutting, welding or additive manufacturing of parts intended for the nuclear, aeronautical, naval, automotive industries.

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