WO2023031234A1

WO2023031234A1 - Nozzle device and method for laser deposition welding

Info

Publication number: WO2023031234A1
Application number: PCT/EP2022/074136
Authority: WO
Inventors: Stephan KOSS
Original assignee: Rheinisch-Westfälische Technische Hochschule (Rwth) Aachen Körperschaft Des Öffentlichen Rechts
Priority date: 2021-09-06
Filing date: 2022-08-30
Publication date: 2023-03-09
Also published as: DE102021122972A1

Abstract

The invention relates to a nozzle device for emitting powdered material in laser deposition welding, wherein the nozzle device is arranged around a passage region (D), through which a laser beam (L) can be passed and with which powdered material can be emitted, wherein the nozzle device has a first nozzle arrangement (2), with which powdered material can be emitted to a first powder focus (PF₁) and at least one further nozzle arrangement (3), with which powdered material can be emitted to at least one further powder focus (PF₂), wherein the powder foci (PF₁, PF₂) of the nozzle arrangements (2, 3) are adjustable in their relative position in relation to one another. The invention also relates to a method for laser deposition welding in which a molten pool is produced by a laser beam (L), in particular a focused laser beam (L), on a component surface (B) and powdered material is emitted in the direction of the molten pool by means of a powder nozzle arrangement (2, 3), wherein the material is melted and applied to the component surface (B), wherein at least two powder foci (PF₁, PF₂) of powdered material are produced by a nozzle arrangement (2, 3).

Description

Nozzle device and method for laser deposition welding

The invention relates to a nozzle device for laser deposition welding, in particular for emitting powdered material during laser deposition welding, the nozzle device being arranged around a passage area through which a laser beam can be guided and with which powdered material can be emitted.

The invention preferably provides that the nozzle device has a first nozzle arrangement, with which powdered material can be emitted to a first powder focus, and has at least one further nozzle arrangement, with which powdered material can be emitted to at least one further powder focus, the powder focuses of the nozzle arrangements are adjustable in the relative position to each other.

The invention also relates to a method for laser build-up welding, in which a molten pool is produced on a component surface with a laser beam, in particular a focused laser beam, and powdered material is emitted in the direction of the molten pool by means of a nozzle device with at least two nozzle arrangements, the material being melted and on the Component surface is applied. At least two powder gas jets are preferably generated with the nozzle arrangements of the nozzle device, with the powder in each of the at least two powder gas jets being directed at a different powder focus. The relative position of the powder focus can be changed. Laser cladding is a state-of-the-art process for creating coatings and 3D geometries on component surfaces. In this process, it can be provided that the particles enter the molten bath not yet molten and are only melted there. It can also be provided that the particles in the laser beam are already melted before they enter the melt pool and/or before they hit the component surface and enter the melt pool in molten form and/or hit the component surface. These variants can also be used in the invention.

In previous applications, the powdered material is fed laterally or coaxially to the laser beam as a powder gas jet, the focus of which is usually positioned in the melt pool or above it.

In the prior art, in most cases with a nozzle device, the powdered material is emitted to a single focus, which means that the powdered material emitted by the nozzle is directed to the focus location after leaving the nozzle and interacts there with the laser beam.

The document DE 11 2015 001 289 T5 shows, for example, a nozzle device with two material feed parts, each of which generates a powder gas jet that is guided from a specific direction laterally to the laser beam. The generated powder gas jets cross each other and the laser beam in a single powder focus, whereby this one powder focus can be changed depending on the height of the nozzle device above a component surface.

If material combinations are to be applied to the component surface, this has so far been done in such a way that the materials are first mixed in powder form in order to then be emitted as a powder combination. In the prior art and in the invention, powdered material is emitted by means of a conveying gas or carrier gas, with which the powdered material particles are carried along. The problem with material combinations is that the process parameters for the different materials, such as the interaction time with the laser beam, cannot be controlled separately.

In addition, multi-layer systems can only be realized by several separate passes over the component surface.

It is advantageous for the invention if the powder material is not emitted from one or only a few directions laterally and crossing the laser beam from a nozzle arrangement of the nozzle device, but if, for example, a hollow cone-shaped powder gas jet is generated with an annular gap nozzle, or if the nozzle arrangement has several, in particular at least has three individual nozzle openings which are arranged on a common circle, with each nozzle opening being able to generate a single partial powder gas jet which is directed towards the powder focus of this nozzle arrangement, with all partial powder gas jets adding up to form a powder gas jet of this nozzle arrangement.

The powder gas jet supplemented from the powder gas partial jets is also in this case at least essentially in the form of a hollow cone, but does not form a closed but rather an open/interrupted (truncated) cone, with the interruptions lying between the powder gas partial jets. Both variants can preferably also be used alternatively or cumulatively in the nozzle arrangements of the invention.

It is fundamentally known in the state of the art to generate powder gas jets of the above-mentioned types in the form of a hollow cone. For example, DE 10 2019 124 518 A1 shows a nozzle device with two nozzle arrangements, each of which can be used to generate an interrupted powder gas jet in the form of a hollow cone. Both powder gas jets are emitted from the nozzle arrangements to different powder foci, whose position relative to one another cannot be changed. A specific nozzle device with defined focus positions must therefore be used for a specific selected coating process. The focus positions cannot be varied during a coating process. The document EP 3 159 094 A1 also shows a nozzle device with a plurality of nozzle arrangements, a closed hollow cone-shaped powder gas jet being able to be produced with a nozzle arrangement which has an annular gap as the nozzle opening, and interrupted hollow cone-shaped powder gas jets with other nozzle arrangements which have several individual nozzle openings on a common circle . The position of the powder focus of the closed, hollow cone-shaped powder gas jet is always the same here and lies on the laser beam axis. The position of the powder focus of the interrupted hollow cone-shaped powder gas jets can be changed along the laser beam axis. This is done by deflecting each partial powder gas jet of this nozzle arrangement after emission from the nozzle arrangement by means of baffle plates at a distance from the nozzle opening while the emission direction of the respective nozzle arrangement always remains the same. Although this allows the powder focus to be changed, it has a strong negative impact on the quality of the powder focus, since each partial powder gas jet has a predetermined cross section and, when reflected at the baffle plate, the powder particles from different cross-sectional areas cross each other, resulting in strong scattering around the baffle plates reflection area lying around.

It is therefore an object of the invention to enable the application of different materials with different process parameters in the application process. Another object is to be able to produce a multi-layer system with only one pass. Preferably, the invention should make it possible to produce a different, preferably locally variable powder focus of high quality when using a plurality of nozzle arrangements.

This object is achieved according to the invention with a nozzle device of the type mentioned at the outset in that the nozzle device has a first nozzle arrangement with which powdered material can be emitted to a first powder focus and has at least one further nozzle arrangement with which powdered material can be emitted to at least one further powder focus , wherein the powder focuses of the nozzle arrays in the relative Position to each other are adjustable. This is preferably done in that the emission direction, in particular the mean emission direction of the powder gas jets of the respective nozzle arrangement, can be changed or is changed according to the method, in particular without having an effect on the emitted powder gas jet after a powder gas jet has been emitted from the nozzle arrangement, in particular from its at least one nozzle opening gain weight. The powder gas jet and the powder focus generated by this thus retains its quality, even if the powder focus is changed.

According to the method, a plurality of powder gas jets can be generated with such a nozzle device, with a powder gas jet preferably comprising all the powdered material that is emitted from an individual nozzle arrangement of the nozzle device to a powder focus specific to this nozzle arrangement. Such a jet can also be composed of partial jets, all of which are directed from the same nozzle arrangement to the same powder focus.

With the device and the method, there is therefore preferably also the possibility of emitting different powdery materials, in particular powder of a different composition, with the different nozzle arrangements. However, it is also possible to emit powder of the same composition with the at least two different nozzle arrangements. In both options, the process parameters and/or geometry parameters can preferably be selected differently according to the invention for each nozzle arrangement.

Typical process parameters are, for example, the powder focus position to the component surface and/or to the laser beam, in particular its focus, or the powder focuses to each other, the speed of the powdered material in the powder gas jet, the pressure and/or the volume flow of the respective conveying gas, the volume flow or mass flow of the respective powdered material materials. A possible geometry parameter is, for example, the size of the nozzle exit area. Due to the adjustability of the powder focuses relative to one another, it is possible to adjust each of the powder focuses in an application-specific manner.

Provision can preferably be made for the relative position of the powder focuses to be set or changed at least before the application of material is carried out. The invention can particularly preferably provide that changes in the relative position of the powder focuses are also made while a material application is being carried out. For this purpose, it can be provided that the powder focuses are adjusted by means of actuators that influence the nozzle arrangements and/or by changing the flow parameters.

In addition or as an alternative to the position of the powder focus as a process parameter, the use of a plurality of (at least two) nozzle arrangements, which can be provided, also includes at least one process parameter or geometry parameter, in particular from the aforementioned parameters, at least initially before or during the implementation of a material application change, especially if this change does not affect the focus position. The invention can thus distinguish between those parameters whose change affects the focus position and those where this is not the case. Both types of parameters can be changed independently for the different nozzle arrangements.

A structurally preferred embodiment can provide that at least one of the nozzle arrangements has a nozzle opening designed as an annular gap. A powder gas jet in the form of a hollow cone can be generated with such an arrangement, which converges to the powder focus of this nozzle arrangement. In this case, the powder gas jet in the form of a carbon cone preferably has a closed cone surface. It is preferably provided that the annular gap extends around the laser beam axis. This results in a powder gas jet that is closed and converging, in particular in the form of a hollow cone, in the circumferential direction, in particular in the circumferential direction around a laser beam. The convergence of the powder gas jet after the annular gap can be characterized, for example be achieved that the powder particles in the nozzle arrangement already have a velocity vector before exiting from the annular gap, which points to the powder focus. A corresponding channel guide can be provided in the nozzle arrangement for this purpose. For example, the channel can have an annular gap-shaped cross-section which decreases, in particular linearly, in the direction of the annular gap-shaped nozzle opening.

In another embodiment, provision can preferably be made for at least one of the nozzle arrangements to have a plurality of individual nozzle openings, in particular at least three nozzle openings, which are arranged on a common circle, with each nozzle opening being able to generate an individual powder gas partial jet which is directed onto the powder focus of these nozzle arrangements , in particular that converges to the powder focus of this nozzle arrangement. Here, too, provision can preferably be made for the said circle to extend around the laser beam axis, in particular in a plane perpendicular or at least transverse to the laser beam. All of the partial powder gas jets combine to form a powder gas jet of this nozzle arrangement. This supplemented powder gas jet can also be regarded as having the shape of a hollow cone, but with a perforated cone surface. Here, too, the direction of the powder gas partial jets after the respective nozzle opening can be achieved, for example, by the powder particles in the nozzle arrangement already having a velocity vector before exiting from the respective nozzle opening, which points to the powder focus. For this purpose, a corresponding channel guide can be provided in front of each nozzle opening of the nozzle arrangement. The multiple channels of such a nozzle arrangement, in particular the central longitudinal axes of these channels, can lie on a truncated cone surface in an element forming this nozzle arrangement.

It is particularly preferred if the at least one nozzle arrangement has a plurality of individual nozzle elements, each with a nozzle opening, in particular the emission direction of which can be changed, in particular synchronously for all nozzle elements. For example, three or more nozzle openings can be provided. It is thus possible to change the direction of the partial powder gas jets with this nozzle arrangement and thus to shift the position of the powder focus.

The invention can provide for combining the various nozzle arrangements of the aforementioned type in a nozzle device of the invention, or else using only one type of the aforementioned nozzle arrangements in a nozzle device of the type according to the invention.

When using at least two nozzle arrangements, each with several individual nozzle openings, it can be provided, for example, that the individual nozzle openings of a first nozzle arrangement are arranged offset to one another in the circumferential direction in relation to the individual nozzle openings of at least one further, in particular a second nozzle arrangement. This results in an advantageous guidance of the partial powder gas jets up to the respective powder focus without influencing the powder gas jets with one another.

It is regarded as structurally advantageous if at least one nozzle arrangement surrounds another nozzle arrangement.

For example, it can be provided that at least one of the nozzle arrangements is formed by a hollow element in the shape of a segment of a cone, in the wall of which at least one feed channel is arranged, with which powdered material can be fed to the at least one nozzle opening, with the element in the shape of a segment of a cone surrounding at least one further nozzle arrangement. It can preferably be provided here that the element in the form of a segment of a cone of this (particularly outer) nozzle arrangement is designed in the shape of a segment of a cone on its radially outer surface and on its radially inner surface, preferably with the same cone angles in each case.

The at least one surrounded (in particular inner) nozzle arrangement can also have a surface that is also in the shape of a segment of a cone, at least on its outside or radially outer surface. Preferably, the cone angle of the radially outer surface of the surrounded (particularly inner) Nozzle assembly correspond to the cone angle of the radially inner surface of the surrounding (particularly outer) nozzle assembly. The radial direction is preferably to be understood in relation to the direction of the laser beam axis.

On the radially inner surface, the surrounded (in particular inner) nozzle arrangement can also be designed in the shape of a segment of a cone, but can also be cylindrical. If the radially inner surface of the surrounded (in particular inner) nozzle arrangement is designed in the shape of a segment of a cone, the cone angle can be different, e.g. smaller, than the cone angle of its radially outer surface.

Preferably, the design of the shape of the radially inner surface of such a surrounded (in particular inner) nozzle arrangement, which in turn directly surrounds the laser beam, is unimportant for the invention, at least as long as there is enough free space around the laser beam so that it can pass through this nozzle arrangement.

The invention can preferably provide that the at least two nozzle arrangements are fastened to a common holder, with at least one of the nozzle arrangements being movable relative to another, preferably with the nozzle arrangements each being adjustably fastened independently of one another. After adjustment, the at least two nozzle arrangements can be moved together over the common mount, in particular in order to follow the laser beam with the powder focuses.

The changeable adjustment of the nozzle arrangement preferably means that the mean emission direction of the emitted powder gas jet changes, preferably relative to the laser beam, but remains constant after emission from the nozzle arrangement, especially after leaving the nozzle opening. In nozzle arrangements that have a hollow cone-shaped closed or perforated powder gas jet produce, the mean emission direction preferably corresponds to the direction of the cone axis, the powder focus more preferably lying on the cone axis. The invention can thus preferably also provide for the cone axis direction of each nozzle arrangement to be adjusted relative to the laser beam.

It is preferred if at least one of the nozzle arrangements, preferably each nozzle arrangement, can be displaced on the common holder in the direction of a laser beam axis or perpendicular to a component surface and/or can be displaced perpendicular to a laser beam axis and/or parallel to a component surface and/or to a component surface Laser beam axis is tiltable.

Changing the relative position of the foci can preferably be achieved in various ways.

For example, the position of the nozzle arrangements relative to each other can be changed, in particular by shifting the nozzle arrangements to one another in the direction of the laser beam or perpendicular to the component surface or perpendicular to the laser beam or parallel to the component surface or by tilting the emission directions of the nozzle arrangements to one another or relative to the laser beam.

A respective nozzle arrangement preferably comprises an element, in particular a hollow-cone-shaped element, which comprises the at least one channel and the at least one nozzle opening or all channels and nozzle openings for generating the at least one powder gas jet. The relative arrangement of the at least one channel and the at least one nozzle opening in the element is preferably fixed, so that according to the invention it can preferably be provided that the entire element, which comprises the at least one channel and the at least one nozzle opening, is moved in order to to change the focus position.

Alternatively or cumulatively, it can also be provided to change the emission direction of individual nozzle elements of the same nozzle arrangement. For this example, nozzle elements or at least one nozzle element on the nozzle arrangement be movably arranged, for example be movably seconded with a respective actuator. Such a nozzle element can, for example, comprise a channel section through which the powder material flows/can flow, the extension direction of which can be changed, for example by means of a movable mounting of the nozzle element, for example by means of a spherical mounting. A nozzle element can be formed, for example, by a component which has an above-mentioned feed channel for the powder material. In this respect, the invention can preferably provide for changing the extension direction of a respective feed channel of a nozzle arrangement.

The focus position can preferably also be influenced by changing the material composition of the at least one powder (partial) jet generated by a nozzle arrangement, in particular by changing the relative proportions of conveying gas and powdered material or by changing the speed of the powdered material, in particular the particle speed, by a Nozzle arrangement through and generated by the structural adjustment of the respective nozzle opening angle, and / or the relative positioning of the individual nozzle outlets in a plane, preferably a plane perpendicular to the laser beam axis and / or in the direction of the laser beam.

The focus position can also be changed by changing the interaction of the at least one powder jet generated by a nozzle arrangement or of the plurality of partial powder gas jets with a protective gas jet.

In particular, it is essential for the invention that the powder gas jet of each nozzle arrangement remains unchanged after emission with regard to its emission direction, preferably the central emission direction. The invention thus advantageously produces at least two powder gas jets, preferably powder gas jets in the form of a hollow cone, each with an adjustable emission direction. The emission direction can preferably be understood as the direction with which the powder gas jet or a partial powder gas jet forming the powder gas jet the nozzle arrangement at the leaves the nozzle opening. The individual emission direction of different hollow cone-shaped partial powder gas jets or different areas of a hollow cone-shaped powder gas jet can be different, but the angle to the cone axis is preferably the same for all partial powder gas jets/areas. In this respect, a mean emission direction, which can correspond to the axis of the cone, preferably results for a powder gas jet in the form of a hollow cone.

Preferably, at least in the case of powder gas jets in the form of a hollow cone, the cone axis can thus be understood as the mean emission direction of the powder gas jet or of the multiple powder gas partial jets forming it.

The invention can, for example, provide for positioning the powder foci of at least two nozzle arrangements offset in relation to one another in the direction of the laser beam axis, in particular being able to change this offset, preferably also during a production operation. In this way, for example, the material of one nozzle arrangement can be shielded from the material of the at least one other nozzle arrangement.

Provision can also be made to position the powder focuses of at least two nozzle arrangements offset from one another perpendicularly to the direction of the laser beam axis, in particular to be able to change this offset, preferably also during a production operation. The offset can preferably be in the direction of travel of the laser beam. This can, for example, prevent shielding. This preferably also results in the possibility of producing multi-layer systems in one pass. The invention can provide for the offset to be newly adapted to a changing direction of travel.

The aforementioned options for offsetting can preferably also be combined. The powder focuses can preferably be offset from one another in the direction of the laser beam axis and/or perpendicular thereto and/or also in a horizontal plane and/or a plane parallel to the component surface be, in particular, this offset can be changed, preferably during a manufacturing operation.

Advantageous embodiments of the invention are described with reference to the figures.

FIGS. 1A to 1D show versions of exactly two nozzle arrangements of a nozzle device according to the invention for laser deposition welding, which surround a passage area D through which a laser beam L can pass through the nozzle arrangements 2, 3. The figures show views of the nozzle openings in the direction of axis 1 of a laser beam, not shown here, which is perpendicular to the plane of the paper.

In FIG. 1, both nozzle arrangements 2, 3 are formed with nozzle openings 2a, 3a in the form of annular gaps. Both nozzle arrangements 2, 3 each produce their own hollow cone-shaped powder gas jet Pi, P2, which converges in the direction of a specific powder focus PF1, PF2. Both annular gap-shaped nozzle openings 2a, 3a have a common ring center point in the adjustment shown, which can coincide with the laser beam axis 1, but does not have to.

In FIG. 1B, the embodiment is such that both nozzle arrangements 2, 3 each have a plurality of, here three, nozzle openings 2a and 3a. The nozzle openings 2a lie on a common circle K1 and the nozzle openings 3a lie on another common circle K2.

Figures 1C and 1D relate to the combination of the designs of the nozzle arrangements according to Figure 1A and 1B.

The adjustment of the nozzle arrangements 2, 3 shown is such in all the embodiments of FIGS. 1A to 1D that the nozzle arrangements 2, 3 are coaxial to one another and preferably also coaxial to the axis 1 of the laser beam. This results in each powder focus PF1 , PF2 lying on the laser beam axis 1 . The mean emission direction is preferably in each case the direction between the circle center or ring center of the nozzle arrangement and the powder focus PFi, PF2 of this nozzle arrangement 2, 3.

FIGS. 2A to 2D show the possibilities of changing the focal positions relative to one another, in that the center points of the circles or ring centers are shifted relative to one another. This produces an offset of the foci PF1, PF2 perpendicular to the laser beam axis 1, preferably with the circle/ring center point of the outer nozzle arrangement 3 remaining on the laser beam axis 1 here. So only one of the center points can be shifted, with the other lying on the laser beam axis 1. Both centers can also be positioned deviating from the laser beam axis 1.

FIG. 3 shows a side sectional view of an embodiment of the nozzle arrangements 2 and 3 with an offset Ax relative to one another, with the outer nozzle arrangement 3 preferably lying coaxially to the laser beam axis 1 .

The focal position relative to one another can also be changed by changing at least one of the emission angles/nozzle opening angles β1 or β2 within at least one of the two nozzle arrangements 2, 3. It can be provided here that the emission angle/nozzle opening angle be related to the laser beam axis 1 or to the central emission direction an annular gap or the individual nozzle openings.

In contrast, Figure 4 visualizes the possibility of changing the mean direction/nozzle exit direction or the mean emission direction of the two nozzle arrangements 2, 3 relative to one another by tilting at least one of the two nozzle arrangements 2, 3 to the other or to the axis 1 of the laser beam, e.g. by the angle hey Here, the inner nozzle arrangement 2 is tilted in relation to the outer nozzle arrangement 3, so that its mean feed direction/nozzle exit direction/emission direction ER changes.

Figure 5 shows compared to Figure 6, the possibility of the nozzle assemblies 2, 3 in the

To move the direction of the laser beam axis 1 against each other and so the To move powder focus PFi, PF2 in the direction of the laser beam axis 1. Figure 5 shows a positioning in which the nozzle openings 2a of the inner nozzle arrangement 2 and the nozzle openings 3a of the outer nozzle arrangement 3 in the direction of the laser beam axis 1 are at a greater distance from one another than in Figure 6. In Figure 6 are the nozzle openings 2a, 3a preferably in the same plane perpendicular to the laser beam axis 1 .

FIGS. 5 and 6 also structurally illustrate the preferred embodiment according to which at least one nozzle arrangement, here the outer one 3, has a hollow element in the shape of a segment of a cone, which surrounds the nozzle arrangement 2, which is preferably also formed in the shape of a segment of a cone, at least on the outside. The nozzle openings 2a, 3a of all nozzle arrangements 2, 3 can preferably be positioned in the same plane perpendicular to the laser beam axis 1, as is shown, for example, in FIG. 6 for this embodiment.

Figure 6 makes it clear that the powder foci can lie on top of one another in the direction of the laser beam axis 1, preferably within the laser beam L, in particular if the nozzle openings 2a, 3a of both arrangements 2, 3 lie in the same plane and have different emission angles, which are shown in Figure 5 are denoted by ai and 02, respectively.

Compared to FIG. 6, FIG. 7 shows that with the same relative position of the nozzle arrangements 2 and 3 to one another, a change in the focus position can also be achieved by changing the flow parameters in the powder gas jets Pi, P2 of at least one of the two nozzle arrangements 2, 3. By changing the pressure of the conveying gas and/or flow speed of the material in the nozzle arrangements and/or changing the flow speed VSG of a protective gas SG, a focus shift relative to one another can also take place, in particular here both in the direction of the laser beam axis 1 and perpendicular thereto. FIG. 7 shows that a multilayer system comprising two layers S1 and S2 on a component surface B can be produced by such a focal position that deviates in both directions. In general, at least the following parameters are to be understood as flow parameters for influencing the focus position: pressure of the conveying gas, the flow rate of the powder material or the conveying gas or protective gas, the powder material composition, or such parameters that influence the flow in the nozzle arrangement.

Claims

Nozzle device for emitting powdered material during laser deposition welding, the nozzle device being arranged around a passage area (D) through which a laser beam (L) can be guided and with which powdered material can be emitted, which has a first nozzle arrangement (2), with the powdered material can be emitted to a first powder focus (PFi) and has at least one further nozzle arrangement (3) with which powdered material can be emitted to at least one further powder focus (PF2), the powder focuses (PF1, PF2) of the nozzle arrangements (2, 3) are adjustable in their relative position to each other, each of the two nozzle assemblies (2, 3) being either a. has a nozzle opening designed as an annular gap, with which a hollow cone-shaped powder gas jet can be generated, which converges to the powder focus of this nozzle arrangement, or b. has a plurality of individual nozzle openings which are arranged on a common circle, with each nozzle opening being able to generate an individual partial powder gas jet which is directed at the powder focus of this nozzle arrangement, with all partial powder gas jets adding up to form a powder gas jet of this nozzle arrangement, and c. the at least two nozzle arrangements (2, 3) can be moved together by means of a common holder, characterized in that d. the powder focuses are adjustable i. by changing the position of the nozzle arrangements (2, 3) relative to one another, and/or ii. by changing the flow parameters in the powder gas jets P1, P2 of at least one of the two nozzle arrangements (2, 3), and/or iii. by changing the emission direction of individual nozzle elements of the same nozzle arrangement. Nozzle device according to Claim 1, characterized in that the powder focuses of the at least two nozzle arrangements can be positioned offset relative to one another perpendicularly to the direction of the laser beam axis. Nozzle device according to one of the preceding claims, characterized in that the individual nozzle openings (2a) of a first nozzle arrangement (2) are offset from the individual nozzle openings (3a) of at least one further, in particular a second nozzle arrangement (3) in the circumferential direction. Nozzle device according to one of the preceding claims, characterized in that at least one nozzle arrangement (3) surrounds another nozzle arrangement (2), in particular wherein the nozzle arrangements (2, 3), or at least their nozzle openings, are spaced apart from one another in the direction of the laser beam axis (1). . Nozzle device according to Claim 4, characterized in that at least one of the nozzle arrangements (3) is formed by a hollow element in the shape of a section of a cone, in the cone wall of which at least one feed channel is arranged, with which powdered material can be fed to the at least one nozzle opening (3a), the element in the shape of a section of a cone surrounds at least one further nozzle arrangement (2), which is preferably designed in the shape of a truncated cone at least on its radially outer surface. 19 Nozzle device according to one of the preceding claims, characterized in that at least one of the at least two nozzle arrangements (2, 3) is fastened to the common holder in an adjustable manner relative to the at least one other nozzle arrangement (2, 3), preferably all nozzle arrangements (2, 3 ) of the at least two nozzle arrangements (2, 3) are each fixed in an adjustable manner independently of one another. Nozzle device according to one of the preceding claims, characterized in that at least one of the nozzle arrangements (2, 3), preferably each nozzle arrangement (2, 3) on the common holder in the direction of a laser beam axis (1) is displaceable and / or perpendicular to a laser beam axis ( 1) is displaceable and/or can be tilted to a laser beam axis, in particular can be tilted about at least one tilting axis perpendicular to the laser beam axis, preferably so that its central longitudinal axis, in particular cone axis, assumes an angle that is not equal to zero to the laser beam axis. Method for laser build-up welding, in which a molten pool is produced with a laser beam (L), in particular a focused laser beam (L), on a component surface (B) and powdered material is emitted in the direction of the molten pool by means of a nozzle device according to one of the preceding claims 1 to 7 , wherein the material is melted and applied to the component surface (B), characterized in that with the at least two nozzle arrangements (2, 3) of the nozzle device at least two powder focuses (PFi, PF2) of powdered material are thereby produced, in particular are adjusted differently, that a. the position of the nozzle arrangements (2, 3) relative to one another is changed, and/or 20 b. at least one flow parameter is changed in at least one of the powder gas jets P1, P2 of at least one of the two nozzle arrangements (2, 3), and/or c. the emission direction of individual nozzle elements of the same nozzle arrangement is changed. Method according to Claim 8, characterized in that the position of the powder focuses (PFi , PF2) relative to one another is set or changed before and/or during the implementation of a material application. Method according to one of the preceding claims 8 or 9, characterized in that a first powdered material is emitted with the first nozzle arrangement (2) and a powdered material is emitted with the at least one further nozzle arrangement (3), which has a different composition than that Material of the first nozzle arrangement (2) and/or any other nozzle arrangement (2). Method according to one of the preceding claims 8 to 10, characterized in that the relative position of the powder focuses (PF1, PF2) is changed by: a. Shifting at least one of the nozzle arrangements (2, 3) relative to another of the nozzle arrangements (2, 3) in the direction of the laser beam axis (1) or perpendicular to the laser beam axis (1) or by tilting at least one of the nozzle arrangements (2, 3) relative to another of the nozzle arrangements, in particular by tilting the emission directions of the nozzle arrangement (2, 3), and/or b. Changing the material composition of the at least one powder jet (Pi, P2) generated by a nozzle arrangement (2 3), in particular by changing the relative proportions of conveying gas and powdered material, and/or 21 c. Changing the flow rate of the powdery material through a nozzle arrangement (2, 3), and/or d. Changing the interaction of the at least one powder jet (Pi, P2) generated by a nozzle arrangement with a protective gas jet, and/or e. Changing the nozzle exit area on at least one, preferably all nozzle openings of the same nozzle arrangement (2, 3).