Process of depositing molten metal wire using a laser beam scanned across the surface of the part

Abstract

The present invention relates to an additive manufacturing method consisting of controlling the movement on the surface of a part of equipment comprising at least one laser whose beam is focused on the output of a feed head delivering at least one metal wire of diameter D, said equipment being controlled to move the interaction zone of the beam of said laser with said at least one wire along a main trajectory representative of the geometry of the part to be manufactured characterized in that said movement of the interaction zone is modulated by a sweep on 2 axes along a longitudinal direction parallel to the velocity vector of said main trajectory and a transverse direction, normal to the velocity vector in the focal plane, said deviation defining a curve swept with a speed greater than the speed of movement along said main trajectory,said 2-axis scanning being controlled by a control system comprising means of parameterizing the control law of said 2-axis scanning for each manufacturing process. Figure to be published: 1,

Description

Title of the invention: Method for depositing molten metal wire using a laser beam scanned onto the surface of the workpiece. Field of the invention

[0001] The present invention relates to the field of DED-wire additive manufacturing, or Directed Energy Deposition-Wire, which consists of melting a metallic material in wire form using concentrated thermal energy (laser, electron beam, and electric arc) and depositing it along a predetermined trajectory to create beads that are juxtaposed to form a layer. The layers of material are superimposed until the final part is obtained, the geometry of which approximates the final object, but which will nevertheless require further machining.

[0002] The design of a part begins with the creation of a 3D model using CAD software. The digital model of the part is then sliced ​​into numerous parallel layers by slicing software, representing the different layers of material required to manufacture the part. The technique involves depositing material onto a platform or component being repaired using a nozzle mounted on a multi-axis arm (generally 4 to 6 axes). The material that feeds the nozzle is supplied in powder or filament form. During deposition, a heat source melts the material simultaneously, usually using a laser, electron beam, electric arc, or plasma jet. This procedure is repeated until the layers have solidified and created or repaired an object.

[0003] High energy density heat sources can be used to melt the wire: the electron beam (EBAM process for 'Electron Beam Additive Manufacturing') or the laser beam (WLAM process for 'Wire Laser Additive Ma-nufactutring').

[0004] The first family of electron beam aerosol (EBAM) solutions requires a high-vacuum chamber equipped with the deposition head, the head's movement axes, the part-holding tooling, and the part to be built itself. It offers very high energy densities and can be scanned at high speed over surfaces. The main limitation of this process is related to vacuum management and its constraints.

[0005] The second family of solutions is based on the use of a laser beam. Unlike electron beam solutions, they can be implemented in ambient air, without requiring a vacuum chamber. The material, generally metallic (steels, aluminum alloys, titanium alloys, etc.), is in powder or The filament is injected into the laser beam using a nozzle, typically mounted on a 6-axis robotic arm. The filament can be fed laterally to the laser beam or centrally using a sophisticated optical system that recombines multiple laser beams to focus them around the filament.

[0006] This technique notably allows the repair of damaged metal parts and the construction, by concentrated energy deposition, of relatively large parts (over one meter in size) requiring minimal, inexpensive tooling and relatively little post-processing. DED processes also make it possible to produce components with composition gradients or composite structures made up of several materials having different compositions and structures. Prior art

[0007] In the prior art, US patent 8598523 is known, describing a method and apparatus for carrying out the treatment for layer fabrication of a three-dimensional part with an electron beam, consisting of exposing the raw material to an electron beam to liquefy the raw material; depositing the raw material onto a substrate as a melt pool deposit, the deposit having a leading edge region in an xy plane with a leading edge region width and a trailing edge region in the xy plane with a trailing edge region width under at least a first treatment condition; controlling the melt pool deposit for at least a preselected condition using dispersion detection from a scanning electron beam simultaneously with the deposition step;automatically modify the first processing condition into a different processing condition based on the information obtained from the comparison step; and repeat the steps at one or more second locations to build, layer by layer, globally along a z-axis that is orthogonal to the xy plane, a three-dimensional workpiece.

[0008] US patent 8809780B2 describes another known example of layer fabrication of a three-dimensional part consisting of feeding a raw material in a solid state to a first predetermined location; exposing the raw material to an electron beam to liquefy it; depositing the raw material onto a substrate as a molten bath deposit, the deposit having a leading edge region in an xy plane with a leading edge region width and a trailing edge region in the xy plane with a trailing edge region width under at least one first processing condition; controlling the molten bath deposit for at least one preselected condition using dispersion detection from a scanning electron beam simultaneously with the deposition step; solidifying the molten bath deposit; and automatically changing the first processing condition to a different processing conditions depending on the information obtained from the comparison step; and repeat the steps at one or more second locations to build layer by layer, globally along a z-axis that is orthogonal to the xy plane, a three-dimensional workpiece.

[0009] Chinese patent CN107470624 is also known, describing an additive manufacturing device for a multi-wire feature gradient structure. The device comprises a support platform, a heat source generation device, a heat source outlet, wire feeding mechanisms, a work platform, and a control system. The heat source outlet and the wire outlet nozzles of the wire feeding mechanisms are both attached to the support platform. The heat source generation device provides a heat source for the metal melting process and is further connected to the heat source outlet. The wire feeding mechanisms comprise wire feeding plates, wire feeding drive motors, and wire outlet nozzles. The wire outlet nozzles of the wire feeding mechanisms are located below the heat source.The control system is electrically connected to the wire drive motors, a carrier platform drive system, and the heat source generation device.

[0010] US patent application 20180272460A1 relates to a method and apparatus specifically designed for the additive manufacturing of materials that are susceptible to hot cracking. The additive manufacturing process may include an attack energy beam for liquefying a raw material to form a melt, and a second energy beam directed downstream of the melt. The second energy beam is designed to enhance the agitation and / or redistribution of the liquid within the melt to prevent hot cracking, reduce porosity, or improve other characteristics of the solidified portion.

[0011] Patent EP2855078B1 describes a method for producing an alloy sample, consisting of installing a directional heat source and a multi-wire feed head and positioning a workpiece surface at a fixed distance from a downward-facing surface of the multi-wire feed head. This method further comprises the following steps:

[0012] heat distribution and feeding of selected lengths of at least two wires having different compositions into a heat-affected region, to form, on the downward-facing portion of the surface, a substantially homogeneous molten alloy portion (17) having a composition defined by the cross-sectional areas and relative proportions of the selected lengths of the at least two wires; and

[0013] cooling of the molten alloy portion to form a solid alloy portion exhibiting the same defined composition as the molten alloy portion

[0014] The multi-wire feed head and the workpiece are configured to allow the feed head to distribute, through an outlet disposed in the downward-facing surface, heat (H) from the directional heat source, along a heat distribution direction (B) aligned with a longitudinal axis of the multi-wire feed head, into a heat-affected region comprising at least a portion of the workpiece surface aligned normally with respect to the heat distribution direction, and to supply, from each of one or more of a multitude of wire outlets disposed on the downward-facing surface, the ends, respectively, of each of one or more of a multitude of wires (1, 2,...) exhibiting diverse compositions at identical angles of inclination with respect to the direction of heat distribution and towards a common focus (F) located in the heat-affected region. . Disadvantages of prior art

[0015] Prior art solutions are not entirely satisfactory.

[0016] Solutions using an electron beam are extremely expensive and complex, requiring a large chamber in which a high vacuum of approximately 103 millibars must be generated before the additive deposition process can begin. All the equipment, the support structure, and the part must be housed within this vacuum chamber. The electron gun and the deflector coils forming the electromagnetic lenses are fixed and relatively heavy, which necessitates movement of the platform supporting the part being formed. Furthermore, the surface finish of the printed part is poor, and the added thicknesses generally require an additional machining step.

[0017] The alternative solution, corresponding to the closest prior art, is based on the use of a laser. The scanning speed of the laser beam is relatively slow due to the inertia of the mechanisms (e.g., electroplating scanner). The deposited surface requires heating to melt the receiving material of the layer and thus ensure the bonding of the deposited layer and perfect metallurgical continuity. The solution proposed in US patent 20180272460A1 involves the use of two separate beams. Solution provided by the invention

[0018] In its most general sense, the invention relates to an additive manufacturing process consisting of controlling the movement on the surface of a part of equipment comprising at least one laser whose beam is focused on the output of a feed head delivering at least one metal wire of diameter D, said equipment being controlled to move the interaction zone of the laser beam with said at least one wire along a main trajectory representative of the geometry of the part to be manufactured characterized in that said displacement of the interaction zone is modulated by a 2-axis sweep along a longitudinal direction parallel to the velocity vector of said main trajectory and a transverse direction, normal to the velocity vector in the focal plane, said deviation defining a swept curve with a speed greater than the speed of movement along said main trajectory, said 2-axis sweep being controlled by a control system comprising means of parameterizing for each manufacturing the control law of said 2-axis sweep.

[0019] Preferably, the axis of the wire feed head forms an angle between 5 and 40° with the axis of the laser beam.

[0020] According to one variant, said feed wire head has a plurality of feed wire outlets converging towards an interaction zone corresponding to the intersection between the 2-axis beam scan and the surface of the part on which the bead is deposited.

[0021] According to another variant, at least two wires are injected into the interaction zone.

[0022] Advantageously, said control system is based on an automaton and a numerical control and controls a modulation of the laser beam and a scanning on the different injected wires.

[0023] According to a particular embodiment, said at least one metal wire comprises at least two different materials.

[0024] According to another embodiment, the movement of the interaction zone is controlled to ensure preheating upstream of the melting bath using the beam not absorbed by the wires.

[0025] Advantageously, the displacement of the interaction zone is modulated by said 2-axis scanning according to a shape adapted to the injection of the filler wires so as to ensure the preheating of the zone including the wire and the part upstream of the melting bath, the melting of the filler wire(s) as well as the maintenance of the melting bath.

[0026] According to one variant, the displacement of the interaction zone is modulated by said 2-axis scanning according to a determined shape to act directly during the deposition of material on the width of the melt bath and thus the geometric characteristics of the deposited material.

[0027] According to another variant, at least two feed wires with different chemical compositions are injected.

[0028] According to another variant, at least two filler wires of different diameters are injected.

[0029] Detailed description of a non-limiting example of embodiment

[0030] The present invention will be better understood upon reading the following description, with reference to the accompanying drawings illustrating non-limiting examples of embodiment where:

[0031] Figure 1 represents a schematic front view of the installation

[0032] Figure 2 represents a schematic view of the closed curve traversed by the laser beam according to a first variant

[0033] Figure 3 represents a schematic view of the closed curve traversed by the laser beam according to a second variant

[0034] Fig. 4 represents the manufacturing diagram of a T-shaped test specimen. General principle of the invention

[0035] The present invention aims to facilitate the manufacturing, without the use of a vacuum chamber, of large parts, typically several tens or even hundreds of centimeters in size, by additive manufacturing, and / or the repair of damaged parts of such large parts, and / or the addition of functional protrusions to parts and the performance of filler welding operations, with a wide range of metallic alloys in the form of wire on spools, in open air or under a controlled atmosphere at ambient pressure. These include, in particular, stainless steel wires, low- and medium-alloy steels, titanium alloys, nickel and cobalt superalloys, aluminum alloys, as well as copper-based materials, and, in general, all conductive or non-conductive materials that are weldable from an operational point of view and available in wire form.

[0036] Given the dimensions of feasible parts and the alloys considered, the sectors mainly targeted are aeronautics, space, defense, transport (including rail and automotive), energy (including nuclear, renewable energies) and petrochemicals.

[0037] Typically, the objective of the invention is to enable the manufacture of large parts at production speeds exceeding 500 cm³ / h. This device must maintain consistent layer-by-layer deposition thanks to its high robustness, despite the high build speed that can be achieved.

[0038] The invention, illustrated by way of schematic example in [Fig. 1], is based on the use of a laser (2), of the fiber laser, disk laser, or diode laser type, emitting a beam conducted by optical fiber to an optical block (3) producing a focused beam (9) which interacts with a wire (6) injected laterally with respect to the laser beam. This interaction melts the wire through the use of a sufficiently high energy density (focused beam). Installation kinematics

[0039] The displacement of the interaction zone (4) between the laser beam (9) and the wire (6) (or wires when the installation provides for supply with several wire injectors is ensured by a combination of two movements:

[0040] A main movement, along a trajectory defined by the configuration of the part to be produced, ensured by a robotic arm or a set of Cartesian motorized axes ensuring the movement of the plate (1) supporting the laser (2), the optical block (3) and the feed coil as well as the wire feed head (6)

[0041] A modulation displacement, along a closed curve, ensured by a galvano-scanner or by a motorized assembly (8) controlling a displacement of the laser (1) and of the optical block (3) relative to the stage (1), along two axes perpendicular to the axis of the laser beam (9).

[0042] The main displacement is determined by the geometry of the part to be produced, in a known manner from a digital definition file of the part for example allowing the generation of the deposition trajectories of the different layers according to an optimized path.

[0043] Prior to the deposition operation, the digital definition of the part is sliced ​​by a multitude of parallel cross-sections. These cross-sections represent the layers of material to be deposited, and the thickness of each corresponds to the thickness of the deposited beads. In each of these layers, the movement of the deposition head is calculated to cover the surface using juxtaposed beads of material. All these movements are recorded in a file constituting the part program, which is then read by the machine's numerical control, which drives the various motorized axes of the machine.

[0044] Typically, the velocity V of the deposition head is on the order of a few tens of centimeters per minute, for example 0.4 to 0.6 meters per minute. It can reach several meters per minute depending on the desired dimension of the beads.

[0045] The second displacement, called modulation, occurs in the vicinity of the melting point of the wire(s), along a curve, in particular a closed curve, defined by a controllable shape, with a longitudinal amplitude along the principal displacement direction, and a transverse amplitude along the direction perpendicular to the principal displacement direction, in the plane defined by the forming layer. Typically, the modulation trajectory has two or more singular points where the velocity along the principal displacement direction is zero. By way of example, the wire diameter is between 1 and 4 millimeters, typically 1.6 mm.

[0046] This modulation displacement features sequences of displacement in the same direction as the main displacement, alternating with sequences of displacement in the opposite direction to the main displacement, to heat the workpiece upstream of the material deposition zone and thus initiate the melt pool, allowing optimization of the energy coupling and the thermal cycle of the process, and optimize the temperature cycle at the time of material deposition on the part or maintain the melting bath.

[0047] The curve of this modulation shift typically takes the form of a "8" or a circle or some other pattern. This modulation shift is described by the laser beam at an adjustable frequency of several hundred hertz, typically 250 Hz.

[0048] Description of an example embodiment of the invention

[0049] The device according to an example of an embodiment of the invention illustrated by figures 1 and 2 consists of a plate (1) actuated by a robotic arm.

[0050] This plate (1) supports an optical fiber carrying the laser beam is connected to an optical module comprising a scanner and optics for shaping the beam produced by a high-power laser source (2) (several kW, up to more than 10kW) associated with an optic (3) for focusing on the wire at a focal point (4) corresponding to the interaction zone between the laser beam and a metallic wire delivered by a power supply system (7).

[0051] The feeding system (7) includes a motorized, controlled system for advancing the wire (6) to the injection system (5) at a maximum speed of a few meters per minute, typically 4 to 6 meters per minute or even 10 m / min. It also includes a cooling nozzle (15) and a diffuser of a neutral or inert gas to protect the molten pool from oxidation.

[0052] A control system based on the use of a numerical control makes it possible to control, using a scanner (8), the scanning of the beam in the focal plane (4) of the optical system (2,3) according to a programmed pattern and frequency, and to move this assembly along a programmed trajectory, consisting of juxtaposed cords allowing to cover the entire surface of the layer.".

[0053] The function of this scanning is to widen the energy supply area, by melting the wire (6) when passing over it in the interaction zone (4), while maintaining a melt pool whose width is fixed by the transverse dimension with respect to the direction of advance ensured by the robotic arm.

[0054] The amplitude of this scan, with the system used in the example described, reaches 10 mm, and the patterns are made with a frequency of 250Hz.

[0055] The scanner (8) commands a trajectory in the shape of a circle, an 8, infinity or dashes, presenting two or three singular points (10 to 12) as illustrated by figures 3 and 4.

[0056] This scanning function also makes it possible to start superficially melting the surface of the part upstream of the melting bath where the molten wire is deposited and to delimit more precisely the edges of the bead of deposited material.

[0057] The wire (6) is injected laterally with respect to the beam (9), at an angle of approximately 30° or less. This lateral injection coupled with beam scanning offers several advantages:

[0058] This configuration is relatively insensitive to wire / beam alignment errors. Even if the wire is slightly misaligned, the beam will still be able to melt it with the same efficiency.

[0059] It becomes possible to use several simultaneous wire injections (6, 16, 26) in the focused beam scanning, allowing all these wires to be melted at the same time in order to feed the same melt pool.

[0060] Several advantages arise from this use of several wires melted simultaneously and controlled modulation of the laser beam (9):

[0061] Maintaining the feed wire within the laser beam interaction requires less fine adjustment than with a fixed beam, thus increasing the operational flexibility of the process.

[0062] To allow the use of several feed wires simultaneously in the laser beam interaction to increase the construction speed,

[0063] In the case of use in multiple filler wire, a "comb" composed of several wires (6, 16, 26) can be individually controlled so as to select the desired wires in the interaction in order to modify the morphology of the deposit during the use of the process: for example in the case of side-by-side beads, especially when the beads are wide, and in order to ensure a better surface geometry.

[0064] The comb made up of several wire injections can be composed of wires of different diameters to more precisely control the melting of the filler metal according to the edges or the center of the bath, and according to the scanning parameters.

[0065] These simultaneous injections can use different types of metal wire, allowing for variations in chemical composition by adjusting the injection speed of each wire. This makes it possible to create material gradients as the buildup progresses, with high responsiveness. While this technique is also possible with the DED-powder process (e.g., CLAD(r)), this process suffers from inertia due to the transport of the powder in the tubes, limiting compositional variations during the formation of a bead. This limitation is overcome by using the simultaneous differential injection of the wires.

[0066] Scanning the beam on the wire(s) also allows the use of cored wires, which makes it possible to work with wires whose composition is adapted to the process, allowing, for example, the reinforcement of certain alloying elements in case of volatilization during interaction with the beam, but also extending the range of possibilities of usable wires, with, for example, non-drawingable materials,

[0067] Controlling the sweep movements improves the regularity and stability of the weld pool and allows the width of the weld pool to be varied by adjusting the sweep amplitude as well as the height of the weld pool by function of the parameters for modulating the speed of movement along the main trajectory.

[0068] Depending on the position of the wire in the modulation pattern, the part of the beam not absorbed by the wire preheats the part or the previous layer upstream of the melting bath.

[0069] Working with a long focal length offers the advantage of a large depth of field. This depth of field provides great operational flexibility along the Z-axis: the beam characteristics change little over a wide range, thus maintaining performance for wire fusion and its deposition onto the previous layer. This is important because, in this case, profile variations will have only a limited influence on the deposit characteristics.

[0070] Finally, this configuration has the advantage of completely clearing the interaction zone, thus allowing:

[0071] To use sensors to monitor the interaction, measure the deposits in real time, and without the said sensors being too close to the interaction, thus keeping them away from the sources of pollution (projections, fumes, ...)

[0072] To move the focusing optics further away and thus have space to implement effective protection measures to guarantee their lifespan. Furthermore, these protection measures are often based on an air gap, which can disrupt the quality of the gaseous protection of the deposited bead.

[0073] To install effective means of extraction for the emitted fumes

[0074] To have a limited footprint ideal for reaching hard-to-access areas, for example in the case of complicated geometries or parts requiring many means of clamping. Example of a completed project

[0075] Figure 4 illustrates the implementation of the invention for the additive manufacturing of a specimen piece having a cross-section in the shape of a "T". The horizontal arrows (20) represent the principal trajectories to form a layer of one of the bars of the specimen, with the laying order number, and the vertical arrows (30) represent the principal trajectories to form a layer of the other bar of the specimen.

[0076] The characteristics of the installation according to the invention, for this embodiment but also for other configurations of parts to be manufactured, are as follows:

[0077] Material: Inconel 625

[0078] Construction rate 505cm3 / h

[0079] Laser power used: 7500W

[0080] Trajectory speed: 0.5 m / min

[0081] Wire unwinding speed: 4.2 m / min

[0082] Diameter of wire used: 1.6mm

[0083] Angle of the filler wire: 59°

[0084] Free wire length: 20mm

[0085] Angle of incidence of the beam: Normal to the surface

[0086] Layer height: 2.2mm

[0087] Cord width: 12mm

[0088] Lateral offset between cords: 6.4mm

[0089] Modulation pattern: Eight

[0090] Modulation amplitude: 6mm

[0091] Modulation frequency: 250Hz

[0092] For the example described, the dimensions of the test specimen are: 1. Height: 80mm, 2. Wall length: 250mm 3. Wall thickness: 30mm

[0093] The main trajectory includes parallel displacements (20), in the example described a first rectilinear displacement in one direction, over a distance of 220 millimeters, then a shift along the perpendicular direction, with a step of 6.4 mm and a return in the opposite direction, beam off, of 220 millimeters, and reiteration to cover the width of the branch being made.

[0094] Next, the complementary branch layer is produced, with equivalent cycles, with a spacing of 5 mm.

[0095] Next, the deposition head is shifted by an increment of 2.2m in the direction normal to the surface of the deposited layer to make the next layer, with the same kinematics, starting however the first line on the opposite side to the first line of the previous layer, and shifting laterally in the opposite direction, so that the order of material deposition is of the type "1 to 4" for one layer and "4 to 1" for the next layer. Performance achieved with the invention

[0096] The process must therefore make it possible to manufacture large parts at production speeds exceeding 500 cm³ / h. This device must maintain consistent layer-by-layer deposition thanks to its high robustness, despite the high build speed that can be achieved.

[0097] The invention makes it possible to meet the following constraints:

[0098] Allow a high construction speed (greater than 500cm3 / h)

[0099] To produce parts of large dimensions (up to several meters in length and several meters in height and width) by means of a stacking of successive cords.

[0100] To make the process very stable with high reproducibility of the deposited beads and their dimensions

[0101] Enabling process monitoring and control through the integration of optical and non-optical sensors

[0102] Making the process robust and tolerant, allowing the deposition of numerous layers without any intervention

[0103] To have excellent management of thermal aspects in order to be able to consider constructions over very long periods continuously (several days), and limiting stoppages as much as possible

[0104] Limiting the constraints of focusing and adjustment

[0105] Limit the system's footprint in the interaction zone

[0106] Enabling the adaptation of a multi-wire injection system

[0107] Allow the use of wire with diameters between 0.8mm and 3.2mm.

[0108] Limit the number of consumables related to the use of the process

[0109] Make the process easily automatable

[0110] Enabling the mounting of the process on a robotic system

[0111] Ability to use laser power levels up to more than 10KW. Multi-wire injection

[0112] It is advantageous to inject two or more wires into the interaction zone in order to melt more material with the same swept beam. This increases the build speed; moreover, using two wires simultaneously allows for lower wire feed speeds than with a single wire, making them easier to control. It also allows the material supply to be spread across the width of the melt pool, resulting in greater process stability. Finally, it allows for better use of the energy supplied by the beam by optimizing the ratio between the total swept area and the interaction area between the beam and the wires, while preserving the creation and maintenance of the melt pool. Injection of different types of filler wires

[0113] By injecting different filler wires with different chemical compositions, it is possible to influence the chemistry of the weld zone. Thus, by varying the feed rates of each wire, it becomes possible to change the chemical composition of the weld zone and thereby create compositional gradients and consequently property gradients directly during the part construction.

[0114] By injecting wires of different diameters so as to provide appropriate quantities of material in each part of the molten pool. Thus, with 3 wires, larger diameter wires can be placed at the edges of the molten zone to compensate for material settling and cusps where the beam remains longer, and a smaller diameter wire in the center of the molten zone where beam velocities are highest. Optional variant

[0115] A variant consists of modifying the control in real time to adapt the scanning pattern to particular needs: several wires, change in the geometry of the deposited cord.

[0116] In particular, the possibility of adapting the scanning pattern of the laser beam to the different injected wires makes it possible to optimize the efficiency of the coupling and thus better control the melting of these, while ensuring the preheating of the part upstream of the melting bath.

[0117] When using multiple feed wires, a specific injector is used to guide the individual wires into the interaction zone at the desired angles. This injector comprises a body efficiently cooled by a water circuit, and interchangeable tips called 'contact tubes' screwed into this body, which allow the wires to be injected as close as possible to the interaction zone.

Claims

Demands

1. - An additive manufacturing process consisting of controlling the die placement on the surface of a part of equipment comprising at least one laser (2) whose beam (9) is focused on the output of a feed head delivering at least one metal wire (6) of diameter D, said equipment being controlled to move the interaction zone of the beam (9) of said laser (2) with said at least one wire (6) along a main trajectory representative of the geometry of the part to be manufactured characterized in that said displacement of the interaction zone is modulated by a sweep on 2 axes along a longitudinal direction parallel to the velocity vector of said main trajectory and a transverse direction, normal to the velocity vector in the focal plane, said deviation defining a curve swept with a speed greater than the speed of movement along said main trajectory,said 2-axis scanning being controlled by a control system comprising means of parameterizing for each manufacturing process the control law of said 2-axis scanning, according to a curve defined by a controllable shape, said control of the scanning movements adjusting the adjustment of the scanning amplitude according to the modulation parameters of the speed of movement along the main trajectory.

2. - Additive manufacturing process according to claim 1 characterized in that the displacement of the interaction zone (4) between the laser beam (9) and the wire (6) (or wires when the installation provides for supply with several wire injectors) is ensured by a combination of two movements: • A main movement, along a trajectory defined by the configuration of the part to be produced, ensured by a robotic arm or a set of Cartesian motorized axes ensuring the movement of the platform (1) supporting the laser (2), the optical block (3) and the feed spool as well as the wire feed head (6), said main movement being determined by the geometry of the part to be produced • A modulation displacement, along a closed curve, ensured by a galvano-scanner or by a motorized assembly (8) controlling a displacement of the laser (1) and of the optical block (3) relative to the stage (1), along two axes perpendicular to the axis of the laser beam (9).

3. - Additive manufacturing method according to claim 1 characterized in that the axis of the wire feed head forms an angle between 5 and 40° with the axis of the laser beam.

4. - Additive manufacturing method according to claim 1 or 2 characterized in that said filler wire feed head comprises a plurality of filler wire outlets converging towards an interaction zone corresponding to the intersection between the 2-axis beam scan and the surface of the part on which the bead is deposited.

5. - Additive manufacturing method according to claim 1 characterized in that at least two wires are injected into the interaction zone.

6. - Additive manufacturing process according to claim 1 characterized in that said control system is based on an automaton and a numerical control and controls a modulation of the laser beam and a scanning on the different injected wires.

7. - Additive manufacturing process according to claim 1 characterized in that said at least one metal wire comprises at least two different materials.

8. - Additive manufacturing method according to claim 1 characterized in that the displacement of the interaction zone is controlled to ensure preheating upstream of the melt pool using the beam not absorbed by the wires.

9. - Additive manufacturing process according to claim 1 characterized in that the displacement of the interaction zone is modulated by said 2-axis scanning according to a shape adapted to the injection of the filler wires so as to ensure the preheating of the zone including the wire and the part upstream of the melt pool, the melting of the filler wire(s) as well as the maintenance of the melt pool.

10. - Additive manufacturing process according to claim 1 characterized in that the displacement of the interaction zone is modulated by said 2-axis scanning according to a determined shape to act directly during the deposition of material on the width of the melt pool and thus the geometric characteristics of the deposited material.

11. - Additive manufacturing process according to claim 1 characterized in that at least two filler wires of different chemical compositions are injected.

12. - Additive manufacturing process according to claim 1 characterized in which means that at least two filler wires of different diameters are injected.

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