DE102023123703A1 - Jet nozzle with powder unit and process gas unit - Google Patents

Abstract

The present invention relates to a jet nozzle (1) for laser deposition welding along a feed direction (2), having a light channel (3) for guiding at least one laser beam that is directed at a workpiece; a powder unit (7) arranged radially outside the light channel (3) for guiding at least one powder jet that is to be applied to the workpiece, wherein the powder unit (7) forms a powder section (11) in a circumferential direction around the light channel (3); and a process gas unit (60) arranged radially outside the light channel (3) for guiding a process gas, wherein the process gas unit (60) forms a process gas section (61) in the circumferential direction; wherein the process gas section (61) adjoins the powder section (11) at a nozzle mouth (6) in the circumferential direction.

Description

Technical area

The present invention relates to a jet nozzle for laser cladding along a feed direction.

State of the art

Laser cladding is used in repair, coating and/or joining technology. A distinction can be made between conventional laser cladding (laser metal deposition (LMD), direct metal deposition (DMD) or direct energy deposition (DED)) and so-called high-speed laser cladding (HS-LMD or extremely high-speed laser cladding (EHLA)). HS-LMD processes are described, for example, in the published documents EN 10 2011 100 456 A and EN 10 2018 130 798 A1 Another method for laser cladding is described in the Chinese patent application CN109175372A known.

A functional layer can be applied to a workpiece using laser cladding. This generally increases the load-bearing capacity of the workpiece processed using laser cladding compared to an unprocessed workpiece. The functional layer can serve as a wear protection layer, for example. The application of the functional layer is based on melting a workpiece surface, applying a powdered filler material and then cooling it down so that a matrix structure with hard material particles is firmly bonded to the material surface. Laser cladding therefore intervenes in the internal material structure of the workpiece and changes it. This can sometimes result in deficiencies in the internal material structure. These can impair the desired increase in load-bearing capacity. The deficiencies can be microscopic in nature, which is why they can only be identified with great effort.

Description of the invention

Based on the known prior art, it is an object of the present invention to provide an improved jet nozzle for laser deposition welding along a feed direction. The invention aims in particular to increase the welding quality of an applied functional layer and of the workpiece as a whole and to reduce or avoid deficiencies in a weld between a powdered filler material and a material surface. The deficiencies can be bonding errors between the material surface and the applied functional layer or between individual applied functional layers. The deficiencies can also be pores, i.e. air inclusions, that occur within the applied functional layer or between the applied functional layer and the material surface. Pores can occur more frequently, particularly if the material surface is a cast material. The deficiencies can also be cracks that run particularly vertically to the material surface within the applied functional layer. The deficiencies can also consist of powder particles, in particular carbides, of the powdered filler material dissolving in a matrix material of the powdered filler material, which leads to embrittlement of the matrix material. The invention further aims in particular to provide a reliable jet nozzle that is resistant to thermal stress. The invention can further aim to design the jet nozzle in such a way that it ensures reliable and precise laser deposition welding over very high numbers of cycles.

The object is achieved by a jet nozzle having the features of claim 1. Advantageous further developments emerge from the subclaims, the description and the figures.

Accordingly, a jet nozzle for laser cladding along a feed direction is proposed, which has a light channel for guiding at least one laser beam that is directed at a workpiece. Laser cladding can be a method for high-speed laser cladding (HS-LMD). The feed direction is the direction along which the jet nozzle moves relative to the workpiece. It can result from a movement, in particular a rotational movement, of the workpiece, from a movement of the jet nozzle or from a superposition of both movements. The feed direction and the correlating feed movement can be constant over the course of the process. Alternatively, they can vary with the respective process stage. The workpiece can be a rotationally symmetrical workpiece, such as a brake disk, a hydraulic cylinder, a pressure roller or a plain bearing. The laser beam can shine through the light channel. It can be provided by a laser source, from which the laser beam is guided by a fiber optic cable to a laser system that splits the laser beam using a collimation lens and focuses it in a process-appropriate manner using laser optics before it enters the jet nozzle. The light The light channel can be a hollow channel that runs through the entire jet nozzle along a longitudinal direction. In addition to the laser beam, a process gas can also be guided to the workpiece surface through the light channel.

The jet nozzle also has a powder unit arranged radially outside the light channel for guiding at least one powder jet that is to be applied to the workpiece, the powder unit forming a powder section in a circumferential direction around the light channel. The powder unit can be radially outside the light channel starting from the longitudinal direction of the jet nozzle and can be part of an external structure that surrounds the light channel. The powder jet can guide a powdery additional material that consists of hard material particles, in particular carbides, and a matrix material. The powder unit can be the part of the jet nozzle that is intended to guide the powdery additional material directly or indirectly. The powder unit can have injector guides into which powder injectors can be inserted. It can also have an annular gap within which the powdery additional material is guided. At a nozzle mouth, the powder unit forms a powder section in a circumferential direction around the light channel. The powder unit can be part of the nozzle mouth. The nozzle mouth is the part of the jet nozzle facing the workpiece. The end section of the nozzle mouth has a distal region. This represents the part of the nozzle mouth that is closest to the workpiece. On the section facing away from the workpiece, the jet nozzle has a proximal region and a flange section. The proximal region and the flange section are the part of the jet nozzle facing away from the workpiece. The nozzle can be coupled to another component of the laser system, such as laser optics or a process unit, via the flange section. In the plan view, the powder section can run at least in sections along an opening of the light channel.

The jet nozzle also has a process gas unit arranged radially outside the light channel for guiding a process gas, the process gas unit forming a process gas section in the circumferential direction. The process gas unit can be located radially outside the light channel starting from the longitudinal direction of the jet nozzle and can be part of the external structure that surrounds the light channel. The process gas can have a positive effect on the powder caustic and the workpiece processing caused by it. The process gas unit can be the part of the jet nozzle that is intended to guide the process gas directly or indirectly. The process gas unit can have injector guides into which additional injectors can be inserted. It can also have an annular gap within which the process gas is guided. At the nozzle mouth, the process gas unit forms a process gas section in a circumferential direction around the light channel. The process gas unit can be part of the nozzle mouth. In plan view, the process gas section can run at least partially along the opening of the light channel. The process gas section may be the part of the process gas unit from which the process gas exits the jet nozzle.

The process gas section adjoins the powder section at the nozzle mouth in the circumferential direction. The process gas section is thus immediately adjacent to the powder section in the circumferential direction. The process gas can thus have a stabilizing effect on the powder caustic and the ongoing laser deposition welding. The process gas section can adjoin the powder section in such a way that a transition takes place in the circumferential direction such that an interior is separated from the process gas section and the powder section from an exterior. The separation can be such that as little fluid as possible is exchanged between the interior and the exterior. This can help to stabilize the process zones and simultaneously prevent the powder particles from sticking to one end of the jet nozzle, thus increasing the service life of the jet nozzle.

The jet nozzle can thus bring about increased variability (i) in the laser beam guidance, (ii) in the application of a powdered filler material, (iii) in the heat management, (iv) in the protection of the laser system including the jet nozzle. It enables the provision of several independent process zones with high precision. The process zones can be divided into zones for laser cladding and zones for pre- and/or post-processing. In the zones for laser cladding, an interaction takes place between at least one laser beam and a powdered filler material. The pre- and/or post-processing can be cleaning the material surface, preheating the material surface before the powdered filler material is applied, post-heating the material surface after the powdered filler material has been applied, or a combination thereof. During pre- and/or post-processing, the laser beam can hit the workpiece without interacting with the powdered filler material. The independent process zones can increase the welding quality and thus the resilience of the applied functional layer, in particular the wear protection layer, and the workpiece as a whole. An additional process gas can stabilize the process zones and increase the precision. sion of laser cladding as well as the service life of the jet nozzle.

In particular, the jet nozzle can reduce the occurrence of fusion defects. This is because fusion defects can occur when the surface heated by the laser beam, such as the workpiece or a previously welded functional layer, has not been heated sufficiently. This lack of heating can be the result of the laser power of an individual laser beam being kept low in order to avoid overheating of the powdered filler material. The increased variability of the laser beam guidance, the increased variability of the application of a powdered filler material and/or the increased variability of the heat management of the jet nozzle can reduce or even prevent the occurrence of fusion defects, in particular by the process gas section, which is arranged in the circumferential direction next to the powder section, stabilizing the laser beam guidance and/or the powder caustic.

Furthermore, the jet nozzle can reduce the occurrence of pores between the welded functional layer and the surface heated by the laser beam. Pores can occur when lamellae in the workpiece, in particular graphite lamellae, evaporate due to the laser radiation. Pores can also occur when the surface to be processed has contamination, for example caused by oils, greases, cooling lubricants or oxides, which cannot be completely removed by the welding process. The undesirable evaporation of the contamination can be the result of the laser power of an individual laser beam being set so high that bonding errors due to insufficient heating can be avoided. The increased variability of the laser beam guidance, the increased variability of the application of a powdered filler material and/or the increased variability of the heat management of the jet nozzle can reduce or even prevent the occurrence of pores, in particular by the process gas section, which is arranged in the circumferential direction next to the powder section, stabilizing the laser beam guidance and/or the powder caustic.

In particular, the jet nozzle can reduce the occurrence of cracks in the welded functional layer. Cracks can occur when a temperature gradient between the highly heated powdered filler material and the less heated workpiece surface is so strong that material shrinkage that occurs during cooling results in stresses that cause cracks. Crack formation can be the result of the laser power of an individual laser beam being set so high that bonding errors due to insufficient heating can be avoided. The increased variability of the laser beam guidance, the increased variability of the application of a powdered filler material and/or the increased variability of the heat management of the jet nozzle can reduce or even prevent the occurrence of cracks, in particular by the process gas section, which is arranged in the circumferential direction next to the powder section, stabilizing the laser beam guidance and/or the powder caustic.

Furthermore, the jet nozzle can in particular reduce the dissolution of hard material particles, in particular carbides, in the matrix material. The powdered additional material can comprise hard material particles, in particular carbides, and a matrix material. The hard material particles should be present undissolved in the welded functional layer in order to increase the load-bearing capacity of the functional layer. However, hard material particles can dissolve if the powdered additional material is exposed to too high an irradiation intensity and the hard material particles thus melt. Dissolved hard material particles cause the welded functional layer to become brittle because the matrix material is less ductile, which means that stresses caused by shrinkage during cooling or loading of the workpiece, for example, cannot be absorbed by the matrix material. Due to the increased variability of the laser beam guidance, the increased variability of the application of a powdered filler material and/or the increased variability of the heat management of the blasting nozzle, the dissolution of hard material particles can be reduced or even avoided, in particular by the process gas section, which is arranged in the circumferential direction next to the powder section, stabilizing the laser beam guidance and/or the powder caustics.

In particular, the jet nozzle can prevent powder particles from sticking to the nozzle mouth. Due to the high process heat, the reflected laser radiation and/or a metal vapor flare can generally lead to the filler material sticking to the nozzle mouth or even welding together, which can lead to a disruption of the gas and powder flows, which subsequently affects the process result. The metal vapor flare is a result of the partial evaporation of the material due to laser deposition welding. It can lead to scattering and/or absorption of laser radiation and subsequently affect the preheating of the workpiece. This can further promote the formation of bonding defects. Due to the increased variability of the laser beam guidance, the increased variability of the application of a powder-based By using a suitable filler material and/or the increased variability of the heat management of the jet nozzle, the undesirable dissolution of hard material particles as well as the propagation of the metal vapor flare can be reduced or even avoided, in particular by the process gas section, which is arranged in the circumferential direction next to the powder section, stabilizing the laser beam guidance and/or the powder caustics.

At least one laser beam, in particular at least one circular laser beam and/or an oval laser beam, can be guided within the nozzle mouth in such a way that more than one process zone is formed in interaction with the powdered additional material, which promotes the welding behavior and reduces the deficiencies of the welded joint, in particular the occurrence of bonding defects, pores, cracks and/or the dissolution of carbides in the matrix material, and increases the load-bearing capacity of the applied functional layer. By providing the process gas unit, the process zones can be influenced in a targeted manner. Firstly, the adhesion or even welding of powder particles to the nozzle mouth is prevented. Secondly, the spread of the steam flare can be prevented by keeping it in the area between the nozzle mouth and the workpiece, in particular within the powder section and the process gas section. The process gas section thus helps to reduce the aforementioned deficiencies.

In one embodiment, the process gas unit forms at least one outlet opening on a front side of the jet nozzle, from which the process gas can be guided to the workpiece, wherein in particular in the at least one outlet opening an additional injector for supplying the process gas without additional material is arranged. The outlet opening can be designed on the front side in such a way that the area to which hard material particles can adhere is minimized. The process gas that is guided from the outlet opening can be supported by the process gas that is guided within the light channel. An additional injector can be arranged in each outlet opening. The additional injector differs from the injectors that are arranged in the injector guides of the powder unit. The latter transport the hard material particles to the workpiece surface, the former transport the process gas.

In one embodiment, the process gas section extends at least partially along a slot arc, in particular in an arc shape, around the light channel. The slot arc represents a line surrounding the slot in a sector, analogous to a circular arc. The remaining part of the slot that is not covered by the slot arc along which the process gas section extends can be filled by the powder section. The process gas section can extend at least partially along a partial circle section, in particular the partial circle section that is at the front in the feed direction, in order to form the arc shape. This further contributes to stabilizing the laser beam guidance and/or the powder caustics.

In one embodiment, the process gas section extends in the circumferential direction around the light channel by a wrap angle of between 5° and 180°, in particular between 45° and 120°, relative to a center point of the light channel. The process gas section can thus extend around the light channel by a smaller section than the powder section. This ensures a satisfactory powder supply through the powder unit and in particular injectors arranged therein while avoiding adhesion or spreading of the vapor flare. A precise adaptation of the powder section and the process gas section to the respective process conditions enables efficient welding behavior without deficiencies.

In one embodiment, the process gas section and the powder section together completely surround the light channel in the circumferential direction, i.e. by 360°. The beams emerging from the process gas section and the powder section can thus separate an interior that forms inside the beams and an exterior that forms outside the beams. The metal vapor flare, also called vapor flare, resulting from the interaction of the powder particles with the laser beam cannot thus emerge from the interior, which prevents undesirable interaction of the vapor flare with the workpiece.

In one embodiment, the process gas unit has a feed opening through which the process gas can be fed to the process gas unit, and the process gas unit has at least one outlet opening through which the process gas exits the process gas unit. The feed opening can be coupled to a feed hose that guides the process gas from a gas reservoir to the jet nozzle. The process gas unit can have exactly one feed opening. The at least one outlet opening is fluidically connected to the feed opening and has a shape such that the process gas exits in the direction of the workpiece surface in a process-appropriate manner. Between the feed opening and the at least one outlet opening, at least one distribution arm is provided that guides the process gas. An additional injector. Alternatively, the process gas can exit directly from the distribution arm and/or the outlet opening.

In one embodiment, the process gas unit has several, in particular three, outlet openings, each of which is connected to the one supply opening. The plurality of outlet openings ensures distribution of the process gas along the circumferential direction. As an alternative to the plurality of outlet openings, an arc-slot-like outlet opening can also be provided, which also ensures distribution of the process gas along the circumferential direction. The plurality of outlet openings contributes to stabilizing the steam flare and preventing powder particles from adhering to the nozzle mouth.

In one embodiment, the process gas section is formed in a region of the nozzle mouth facing the feed direction. The region of the nozzle mouth facing the feed direction is provided in a plan view at the end of the nozzle that is close to the feed direction. An end face of the process gas section points in the direction of the workpiece. The process gas section can extend along the circumferential direction around the light channel in an angular range. The angular range in which the process gas section extends can be smaller than the angular range in which the powder section extends. The region in which the process gas section is formed can correlate with the position and orientation of the powder injectors that apply the powdered filler material to the workpiece.

In one embodiment, the powder section has a plurality of injector guides, into each of which a powder injector can be inserted. The injector guides can be cylindrical or conical through-openings in the area of the nozzle mouth, into each of which a powder injector can be inserted. The injector guides can be introduced into the nozzle mouth by means of machining. However, they are preferably already provided in an additive manufacturing of the jet nozzle. The injector guides can be adapted to the powder injector to be used. The injector guides of the powder section differ from the distribution arms of the process gas section. The powder injectors also differ from the additional injectors that convey the process gas.

In one embodiment, an inner diameter of the at least one outlet opening is smaller than an inner diameter of the injector guides. The volume flow of the process gas can be influenced via the inner diameter of the at least one outlet opening. A gas flow rate of process gas through the at least one outlet opening can be in the range between 1 l/min and 100 l/min, in particular between 5 l/min and 50 l/min. The gas flow rate of conveying gas that flows out of the powder injectors in the injector guides and of process gas that flows out of the at least one outlet opening can be essentially the same. It is also possible for process gas to exit the light channel in addition to the outlet openings. The gas flow rates of conveying gas and process gas can also be weighted against each other. For example, the proportion of conveying gas can be greater than that of process gas or vice versa. The respective ratio of process gas to conveying gas can be adjustable depending on the process.

In one embodiment, a first powder injector is prepared to convey a first powder mass flow and a second powder injector is prepared to convey a second powder mass flow, wherein the first powder mass flow differs from the second powder mass flow. The first powder injector can be provided in a first powder section, the second powder injector in a second powder section. The first powder injector can be arranged such that it interacts with the primary beam of the laser beam. The second powder injector can be arranged such that it interacts with the secondary beam of the laser beam. The primary beam and the secondary beam can be identical to one another or transport a different energy. The provision of the first powder mass flow and the second powder mass flow enables the jet nozzle to realize more than one process zone, which further contributes to increased variability of the jet nozzle. The gas flow rate that exits from the at least one outlet opening can be set according to the first powder mass flow of the second powder mass flow.

In one embodiment, the powder section forms an annular gap segment, in particular instead of injector guides. The annular gap segment can form a uniform powder focus that, for example, coincides with the center of the at least one laser beam. In the annular gap segment, the powdery additional material is applied to the workpiece along a horseshoe-shaped beam.

In one embodiment, the light channel is adapted to guide a plurality of laser beams, the plurality having a first laser beam as the primary beam and a second laser beam as the secondary beam. The primary beam and the secondary beam can originate from the same optical fiber cable. A laser light provided can be split into a parallel beam bundle via a collimation lens. The beam bundle can be For example, a wedge plate can be used to form the primary beam and the secondary beam from a single laser beam. In this case, the primary beam and the secondary beam can have the same wavelength and carry the same energy. Alternatively, the primary beam and the secondary beam can differ in terms of their wavelength and energy. The respective centers of the primary beam and the secondary beam can be offset in the feed direction in a line to a center of the light channel.

In one embodiment, the jet nozzle is manufactured using an additive manufacturing process, in particular using powder bed melting. For this purpose, the jet nozzle can be made of copper or a copper alloy, in particular a copper-chromium-zirconium alloy. This is suitable for the additive manufacturing process on the one hand and, on the other hand, ensures sufficient strength, thermal conductivity and heat resistance to withstand the process requirements. In powder bed melting, the material to be processed is present in powder form. A laser beam heats the powder along the intended geometry, which liquefies the powder and bonds it together. Powder bed melting can, for example, be designed as selective laser melting ("SLM") or selective laser sintering ("SLS").

In one embodiment, the nozzle mouth has a bevel by which part of the nozzle mouth is cut off, wherein the bevel is essentially flat and runs in a plane that is inclined with respect to the longitudinal direction of the jet nozzle. The bevel can cut off the powder section and the powder section-free feed section or the process gas section in the circumferential direction around the light channel. The bevel reduces the volume of the nozzle mouth compared to the embodiment in which no bevel is provided. The nozzle mouth thus takes up less installation space. The jet nozzle with the bevel can be used, for example, to coat a brake disk that has a holder that protrudes axially from the functional surface to be coated. The bevel ensures that the jet nozzle can be moved flexibly on the functional surface to be coated and can be moved close to the holder. The bevel can run in the distal area like a passante on the elongated hole. The passante defines the orientation of the bevel on the nozzle mouth. The passante runs in the front face of the jet nozzle facing the workpiece along a straight line or an arc that neither intersects nor touches the slot. The distance of the passante from the center of the light channel is greater than the distance of the corresponding section of the slot from the center of the light channel. The distance between the passante and an outer edge of the slot is selected such that the wall thickness in between ensures sufficient strength and resilience of the jet nozzle.

In one embodiment, the jet nozzle is adapted to guide the laser beam along the longitudinal direction of the jet nozzle, so that the at least one laser beam runs orthogonally to the cross-sectional area. Furthermore, the light channel can be adapted to guide a protective gas to a radially outer section for shielding a process zone.

The features disclosed contribute, partly individually and partly in combination, to overcoming the deficiencies in laser cladding mentioned at the outset.

Short description of the characters

• 1 eine schematische Ansicht einer Strahldüse bei einem Laserauftragschweißen;
• 2 eine Strahldüse in einer Seitenansicht;
• 3 die Strahldüse aus 2 in einer perspektivischen Ansicht;
• 4 die Strahldüse aus 2 verbunden mit weiteren Komponenten;
• 5 die Strahldüse aus 2 in einer Draufsicht auf einen distalen Bereich;
• 6 die Strahldüse aus 2 in einer Draufsicht auf einen Flanschabschnitt;
• 7 eine weitere perspektivische Ansicht der Strahldüse aus 2;
• 8 eine perspektivische Schnittansicht der Strahldüse aus 2;
• 9 die Strahldüse mit einer Prozessgaseinheit in einer Draufsicht auf den distalen Bereich;
• 10 die Strahldüse mit der Prozessgaseinheit in einer Draufsicht auf den distalen Bereich mit einem Pulverfokus, der einem Fokus eines Primärlaserstrahls entspricht;
• 11 die Strahldüse mit der Prozessgaseinheit in einer perspektivischen Ansicht;
• 12 die Strahldüse mit der Prozessgaseinheit in einer Seitenansicht;
• 13 weitere Darstellungen der Strahldüse mit der Prozessgaseinheit;
• 14 eine weitere Ausführungsform der Strahldüse mit einem geometrisch angepassten Düsenmund in einer Seitenansicht; und
• 15 eine weitere Ausführungsform der Strahldüse mit einem geometrisch angepassten Düsenmund in einer Draufsicht.

Preferred further embodiments of the invention are explained in more detail by the following description of the figures.

• 1 a schematic view of a jet nozzle in a laser cladding process;
• 2 a jet nozzle in a side view;
• 3 the jet nozzle 2 in a perspective view;
• 4 the jet nozzle 2 connected to other components;
• 5 the jet nozzle 2 in a plan view of a distal region;
• 6 the jet nozzle 2 in a plan view of a flange section;
• 7 another perspective view of the jet nozzle from 2 ;
• 8 a perspective sectional view of the jet nozzle from 2 ;
• 9 the jet nozzle with a process gas unit in a plan view of the distal area;
• 10 the jet nozzle with the process gas unit in a plan view of the distal area with a powder focus corresponding to a focus of a primary laser beam;
• 11 the jet nozzle with the process gas unit in a perspective view;
• 12 the jet nozzle with the process gas unit in a side view;
• 13 further representations of the jet nozzle with the process gas unit;
• 14 another embodiment of the jet nozzle with a geometrically adapted nozzle mouth in a side view; and
• 15 another embodiment of the jet nozzle with a geometrically adapted nozzle mouth in a top view.

Detailed description of preferred embodiments

Preferred embodiments are described below with reference to the figures. Identical, similar or equivalent elements in the different figures are provided with identical reference symbols, and a repeated description of these elements is partially omitted in order to avoid redundancies.

1 shows a jet nozzle 1 for laser deposition welding along a feed direction 2. The feed direction 2 is the direction along which the jet nozzle 1 moves relative to a workpiece 100. It can result from a movement, in particular a rotational movement, of the workpiece 100, from a movement of the jet nozzle 1 or from a superposition of a movement of the workpiece 100 and the jet nozzle 1. The feed direction 2 and the correlating feed movement can be constant over the course of the process. Alternatively, they can vary with the respective process stage. The workpiece 100 can be a rotationally symmetrical workpiece, such as a brake disk, a hydraulic cylinder, a pressure roller or a plain bearing. At least one laser beam 110 emerges from a light channel 3 with a lateral surface 4. The light channel 3 can also be adapted to guide a process protective gas 150 to a radially outer section to shield a process zone and to prevent oxidation. The light channel 3 is surrounded by an outer structure 5, which has a nozzle mouth 6, which in turn contains a powder unit 7. The powder unit 7 can, for example, have a plurality of injector guides 19 (see 3 ), into each of which a powder injector 16 (for this 4 ). As an alternative to the individual injector guides 19, the powder unit 7 can have a powder ring gap channel. A powdery additional material 120 is directed onto the workpiece 100 via the powder unit 7 and the powder injectors 16 arranged therein. The laser beam 110 heats the workpiece 100 in such a way that a melt pool 130 forms on a material surface. In addition, the laser beam 110 heats the powdery additional material 120, which has hard material particles and a matrix material. For this purpose, the laser beam 110 can have a reduced core intensity. As soon as the melt pool 130 cools, a welded functional layer 140, for example a wear protection layer, is formed from the hard material particles and the matrix material. The welded functional layer 140 makes the material surface more resistant and increases its load-bearing capacity.

2 shows the jet nozzle 1 in a side view, in which the feed direction 2 points out of the plane of the drawing. The jet nozzle 1 can be coupled to other components of a laser system, such as laser optics or a process adapter, via a flange section 9. A proximal region 10 adjoins the flange section 9. A coolant inlet 13 and a coolant outlet 14, which are part of a cooling system of the jet nozzle 1 and which protrude radially from the jet nozzle 1, can be provided at least partially in the proximal region 10. A distal region 8 is formed at the end of the jet nozzle 1 opposite the proximal region 10. The distal region is part of the funnel-shaped nozzle mouth 6. This has a powder section 11 in a circumferential direction around the light channel 3, in which the powder unit 7 is arranged. A powder unit-free feed section 12 adjoins the powder section 11 in the circumferential direction. The feed section 12 can be used as a process gas section 61 (see for example 9 ) which is part of a process gas unit 60.

3 shows the jet nozzle 2 in a perspective view. The light channel 3 is a hollow channel with the outer surface 4, within which the at least one laser beam 110 runs. The outer structure 5 surrounds the light channel 3 from the flange section 9 to the distal region 10. The nozzle mouth 6 is a substantially funnel-shaped region of the jet nozzle 1. The funnel shape of the nozzle mouth 6 serves, among other things, to enable the nozzle mouth 6 to form the plurality of injector guides 19 in the region of the powder unit 7. A powder injector 16 (see 4 ) is used, which directs the powdered additional material 120 in a process-appropriate manner onto the at least one laser beam 110 and/or the workpiece 100. The powder unit 7 extends along the powder section 11, which is followed in the circumferential direction by the powder unit-free feed section 12. The feed section 12 is the area of the nozzle mouth 6 in which no injector guides 19 are provided, so that no powdered additional material 120 is fed through it. In one embodiment, the feed section 12 can be formed as a process gas section 61, so that a process gas is fed through it. The jet nozzle 1 can be manufactured using additive manufacturing processes, in particular by means of powder bed melting. For this purpose, the jet nozzle 1 can consist of a copper-chromium-zirconium alloy. This is suitable for additive manufacturing processes on the one hand and, on the other hand, ensures sufficient strength, thermal conductivity and heat resistance to withstand the process requirements. In powder bed melting, the material to be processed is in powder form. A laser beam heats the powder along the intended geometry, which liquefies the powder and bonds it together. Powder bed melting can, for example, be designed as selective laser melting ("SLM") or selective laser sintering ("SLS").

4 shows the jet nozzle 1 to which additional components are attached. A coupling ring 15 is connected to the flange section 9, which fastens the jet nozzle 1 to the connected unit, for example the laser optics or the process adapter. Powder injectors 16 are inserted into the injector guides 19 of the powder unit 7. The powdery additional material 120 is conveyed by means of the powder injectors 16 and applied to the workpiece 100 with the intended focus. The individual powder injectors 16 can use different powder foci to one another. Alternatively, the powder injectors 16 can be directed at the same focus point. The powder injectors 16 are arranged in the injector guides 19 provided for this purpose in the powder unit 7 in the powder section 11. The feed section 12 is free of powder injectors 16. Furthermore, an inlet nozzle 17 is inserted into the coolant inlet 13 and an outlet nozzle 18 is inserted into the coolant outlet 14. These connect the coolant inlet 13 and the coolant outlet 14 to a coolant circuit.

5 shows the jet nozzle 1 in a plan view of the distal region 8. The cross-sectional area of the light channel 3, which runs orthogonally to the longitudinal direction of the jet nozzle 1, deviates from a circular shape and is elongated in the feed direction 2. In the distal region 8, the cross-sectional area of the light channel 3 is designed in the manner of an elongated hole, in which a partial circular section adjoins two opposite ends of a rectangular section. Two laser beams are guided within the light channel 3, a primary beam 111 and a secondary beam 112. The primary beam 111 and the secondary beam 112 can originate from the same fiber optic cable. A laser light provided can be split into a parallel beam bundle via a collimation lens. The beam bundle can, for example, form the primary beam 111 and the secondary beam 112 from a single laser beam using a wedge plate. The respective centers of the primary beam 111 and the secondary beam 112 are offset in a line in the feed direction 2 to a center 20 of the light channel 3.

In the present case, the secondary beam 112 is located in front of the primary beam 111 in the feed direction 2 and does not interact with a powder caustic. The secondary beam 112 can thus be used to preheat the workpiece 100 before the primary beam 111 and the powdered filler material 120 heated by the primary beam 111 hit the workpiece 100. The secondary beam 112 thus creates a first process zone that serves to preheat the workpiece 100 and the primary beam 111 creates a second process zone that serves to weld the powdered filler material 120 onto the workpiece 100. These different process zones enable flawless welding in which no deficiencies, in particular no fusion defects, pores, cracks and/or dissolution of carbides in the matrix material, occur. It is also possible to guide the secondary beam 112 in the feed direction 2 after the primary beam 111. The secondary beam 112 can thus be used to reheat the workpiece 100 and thus contribute to a more uniform cooling, which prevents the occurrence of inclusions or other imperfections.

The primary beam 111 and the secondary beam 112 are arranged in close proximity to one another. The front partial circle section of the elongated hole in the feed direction 2 is concentric to the secondary beam 112, while the rear partial circle section of the elongated hole is concentric to the primary beam 111. A center point of the cross-sectional area is eccentric to a center point of the primary beam 111 and to a center point of the secondary beam 112. A tertiary beam can also be provided, so that, for example, the secondary beam is arranged in front of the primary beam in the feed direction and the tertiary beam is arranged after the primary beam in the feed direction. The individual laser beams are guided to one another without shielding, so that there is exactly one light channel 3 with exactly one lateral surface 4, which results in minimal thermal losses.

Because the primary beam 111 in 5 in the feed direction 2 is arranged radially offset free behind the secondary jet 112 and the secondary jet 112 serves to preheat the workpiece, it is desirable that the powdered additional material does not interact with the secondary jet 112. This ensures that on the one hand the secondary jet 112 can exclusively perform the function of preheating the workpiece and on the other hand the powdered additional material is only affected by the primary jet 111 and not by the Secondary jet 112 is heated. This is achieved in that the jet nozzle 1 forms the powder unit 7 in the region of the nozzle mouth 6 in such a way that it forms the powder section 11 around the light channel 3 in the circumferential direction, which is followed in the circumferential direction by the powder unit-free feed section 12. In addition to the powder unit 7, the process gas unit 60 can also be formed, which forms the process gas section 61, in which case the feed section 12 is formed as a process gas section 61. The feed section 12 is formed in a region of the nozzle mouth 6 facing the feed direction 2. The powder section 11 extends along the elongated hole which forms the cross-sectional area of the light channel 3 in the distal region 8. Analogous to a circular arc, the powder section 11 extends along an elongated hole arc, in particular horseshoe-shaped, around the light channel 3. The powder section 11 therefore extends in the circumferential direction around the light channel 3 by a wrap angle of less than 360°, in particular between 90° and 330°, more particularly between 180° and 300°, relative to a center point of the light channel. This ensures that the powdery additional material that flows out of the injectors 16, which are inserted in the injector guides 19, only interacts with the primary jet 111. The secondary jet 112 can thus form a process zone that is independent of the primary jet 111. The powder section 11 and the feed section 12 form an elongated hole shape in plan view. This further helps to reduce or avoid the deficiencies identified at the beginning.

6 shows the jet nozzle 1 in a top view of the flange section 9. The cross-sectional area of the light channel 3, which runs orthogonally to the longitudinal direction of the jet nozzle 1, also deviates from a circular shape in the area of the flange section 9 and is elongated in the feed direction 2. The extension of the cross-sectional area can decrease from the distal area 8 to the flange section 9. In the area of the nozzle mouth 6, the cross-sectional area can be elongated in such a way that it is at least 1.5 times, in particular at least twice as large in the feed direction as it is transverse to the feed direction. The flange section 9 has such a radial extension that the injector guides 19 are not visible from the top view of the proximal area 10.

7 shows the jet nozzle 1 in a further perspective view. The nozzle mouth 6 has a curved funnel shape. The injector guides 19, into which the powder injectors 16 can be inserted, are formed within the individual curvatures. In the feed direction 2, the light channel is stretched in a way that deviates from a circular shape in order to achieve the advantages according to the disclosure. In the circumferential direction around the light channel 3, the nozzle mouth 6 has the powder unit 7. This extends in the circumferential direction around the light channel 3 along the powder section 11, which is followed by the powder-free feed section 12.

8 shows a perspective sectional view of the jet nozzle 1. The light channel 3 has a conical shape, so that the cross-sectional area of the light channel 3 running orthogonally to the longitudinal direction of the jet nozzle 1 is smaller in the distal region 8 than in the proximal region 10. The coolant inlet 13 and the coolant outlet 14 are arranged in the proximal region 10 of the jet nozzle 1 and protrude in the radial direction from the jet nozzle 1. 8 shows an injector guide 19 in section. This is arranged in the powder section 11. In the feed section 12, no injector guide 19 is provided for guiding the powder jet. The jet nozzle 1 has a cooling system 30.

A cooling medium, for example water, is returned to a radially inner cooling chamber 31 via the coolant inlet 13 in the proximal region 10. The cooling medium can be distributed in the proximal region 10 in the circumferential direction around the light channel 3. The cooling medium runs from the proximal region 10 to the nozzle mouth 6. The radially inner cooling chamber 31 is formed at least in the nozzle mouth 6. It can run from the distal region 8 to the proximal region 10 and can be designed in the manner of an annular gap segment that extends circumferentially around the light channel 3. In the region of the nozzle mouth 6, the radially inner cooling chamber 31 extends circumferentially around the light channel 3. The radially inner cooling chamber 31 has a constant width in the radial direction in the region of the nozzle mouth 6 and is concentric to the light channel 3 in a cross-sectional area that runs orthogonal to a longitudinal direction of the jet nozzle 1.

In the distal region 8, a transition 32 is provided between the radially inner cooling chamber 31 and a radially outer cooling chamber 33. The radially outer cooling chamber 33 has a radial width that decreases in the radial direction in the region of the nozzle mouth 6 towards the distal region 8. The radially outer cooling chamber 33 extends from the distal region 8 to the proximal region 10, where it supplies the heated coolant to the coolant outlet 14. The transition 32 between the radially inner cooling chamber 31 and the radially outer cooling chamber 33 is arranged in the feed section 12. The feed section 12 does not have any injector guides 19 for guiding the powder jet, which means that there is sufficient installation space for the transition 32.

The radially outer cooling chamber 33 has a cooling structure to increase the surface area. The cooling structure can be manufactured using an additive manufacturing process. It ensures that the cooling medium comes into contact with as much surface area as possible when returning from the distal region 8 to the proximal region 10 in order to promote heat dissipation. The cooling structure is optimized to cause the lowest possible pressure loss of the cooling medium. This can be achieved by a honeycomb structure 34, as shown in 8 shown can be achieved.

9 shows the jet nozzle 1 in a top view of the distal area 8. The primary beam 111 and the secondary beam 112 are guided within the light channel 3. The secondary beam 112 is in front of the primary beam 111 in the feed direction 2 and does not interact with a powder caustic, as in connection with 5 is described in more detail. When the laser beams interact with the material surface and the powder jet, a vapor flare can form between the jet nozzle 1 and the workpiece 100. If this is not contained, it can interact in an undesirable manner with the at least one laser beam and/or the unprocessed and/or the processed material surface. In the area adjacent to the powder section 11, the feed section 12 can therefore be designed as a process gas section 61. This is formed by the process gas unit 60 arranged radially outside the light channel 3, which directs the process gas onto the workpiece. The process gas section 61 can prevent an undesirable spread of the vapor flare and thus contribute to precise workpiece processing with a robust jet nozzle design. The process gas section 61 can form at least one, in this case three, outlet opening 62. The outlet openings 62 are formed on one end face of the jet nozzle 1. An additional injector for supplying the process gas without additional material can be inserted into the respective outlet opening 62. An inner diameter of the outlet opening 62 can be smaller than an inner diameter of the injector guides 19. The process gas section 61 also prevents powder particles from adhering to the front side of the jet nozzle 1. In this respect, the process gas section 61 also increases the service life of the jet nozzle 1. The process gas section 61 and the powder section 11 can be provided all the way around the elongated hole formed by the light channel 3. The primary jet 111 and the secondary jet 112 are thus completely within the jets that are made up of the powder jet and the process gas jet.

A gas flow rate of process gas through the outlet openings 62 can be in the range between 1 l/min and 100 l/min, in particular between 5 l/min and 50 l/min. The gas flow rate of conveying gas that flows out of the injectors 16 or the injector guides 19 and of process gas that flows out of the outlet openings 62 can be essentially the same. It is also possible for process gas to exit the light channel 3 in addition to the outlet openings 62. The gas flow rates of conveying gas and process gas can also be weighted against each other. For example, the proportion of conveying gas can be greater than that of process gas or vice versa. The respective ratio of process gas to conveying gas can be adjustable depending on the process.

10 shows the view from 9 , in which a wrap angle 26, along which the powder section 11 extends around the center point 20 of the light channel 3, is drawn. In the present case, the wrap angle 26 extends by 240°. The remaining 120° to completely enclose the light channel 3 are formed in the present case by the process gas section 61. The powder jet and the process gas jet thus completely surround the light channel 3. The powder injectors 16 and the injector guides 19 are designed such that the powder jet emerging from them is focused in the first powder focus 21. The primary jet 111 has a jet center point that coincides with a first powder focus 21 and forms a powder caustic. The primary jet 111 and the secondary jet 112 are offset from one another in the feed direction 2. The secondary jet 112 does not interact with the powder caustic. The process gas section 61 prevents the escape of a steam flare and the adhesion of powder particles to the front side of the jet nozzle 1.

11 shows a perspective view of the jet nozzle 1. A feed opening 63 is provided in the process gas section 60. The feed opening 63 is arranged in the area of the nozzle mouth 6 facing away from the workpiece. Process gas is fed to the process gas section 60 via it. Starting from the one feed opening 63, the process gas can be guided to the individual outlet openings 62 through distribution arms 64, which are formed within the process gas section 60. The number of distribution arms 64 corresponds to the number of outlet openings 62. The distribution arms 64 extend within the process gas unit 60 along the nozzle mouth 6 in order to distribute the process gas from the feed opening 63 to the outlet openings 62. The distribution arms 64 can form sections into which additional injectors can be inserted. These can allow the process gas to exit at an angle relative to the workpiece surface. The distribution arms 64 are designed such that the process gas can be directed efficiently and in a process-appropriate manner onto the workpiece surface.

12 shows the jet nozzle 1, the workpiece 100 and the area in between in a side view. The powder unit 7 extends in such a way that the powder jet can be directed from the powder section 11 of the nozzle mouth 6 onto the workpiece 100 in accordance with the process. The powder unit 7 is followed by the process gas unit 60, which guides the process gas from the feed opening 63 via the distribution arms 64 to the outlet opening 62, so that the process gas can be directed from the process gas section 61 of the nozzle mouth 6 onto the workpiece in accordance with the process. The interaction between the primary jet 111, the powder jet and the workpiece surface causes a first vapor flare 65. The interaction between the secondary jet 112 and the material surface causes a second vapor flare 66. The process gas flows out of the outlet openings 62 in such a way that the first vapor flare 65 and the second vapor flare 66 do not exit radially from the extended region of the light channel 3.

13 shows the jet nozzle 1 in three different views. 13 a) is a perspective view. In the area of the nozzle mouth 6 facing the flange section 9, the feed opening 63 is provided in the process gas unit 60. This represents the central interface via which process gas is made available to the nozzle mouth 6. Starting from the feed opening 63, the process gas is distributed along the distribution arms 64, which distribute the process gas from the feed opening 63 along the circumferential direction around the light channel 3. At the distal end of the distribution arms 64 are the outlet openings 62, from which the process gas exits in the direction of the workpiece. The outlet openings 62 are part of the process gas section 61 and they extend in an arc along the circumferential direction around the light channel 3. The powder section 11 adjoins them in a horseshoe shape. Thus, in the present example, the light channel 3 is completely surrounded, i.e. 360°, by the powder section 11 and the process gas section 61.

13 b) is a sectional view. At a rear area in the feed direction 2, the powder unit 7 is provided, which forms the powder section 11 and through which the injector guides 19 extend. The injector guides 19 are adapted to each accommodate a powder injector 16. At a front area in the feed direction 2, the process gas unit 60 is provided, which forms the process gas section 61 and through which the distribution arms 64 extend. A distribution arm 64 can accommodate an additional injector. Alternatively, the process gas is directed directly from the distribution arms 64 to the material surface. The distribution arms 64 have a curved shape along their longitudinal direction. The jet nozzle 1 has the cooling system 30 with the radially inner cooling chamber 31 and the radially outer chamber 33. Due to the design of the feed section 12 as a process gas section, the radially outer cooling chamber 33 surrounds the distribution arms 24 in the front area of the nozzle mouth 6 in the feed direction 2. The process gas can thus contribute to the heat management of the jet nozzle 1.

The jet nozzle 1 has an absorption section 40 on the outer surface 4 of the light channel 3 for absorbing a reflection radiation of the laser beam from the workpiece 100. The absorption section 40 can have a geometry that promotes the absorption of the reflection radiation. The absorption section can extend variably in a circumferential direction around the light channel 3, in particular be designed in the entire circumference of the light channel 3. It can also extend variably in a longitudinal direction of the light channel 3. In particular, no absorption section 40 is formed in the distal outer surface of the nozzle mouth 6, but rather a smooth inner end section in order to be able to clean the inside of the nozzle mouth 6 better. The shape of the absorption section 40 can be adapted to the expected reflection radiation. The absorption section 40 can be made of the same material as the remaining jet nozzle. It can also have a coating. The laser radiation absorbed by the absorption section 40 can be at least partially removed by the cooling system 30. The reflected radiation is absorbed by the absorption section 40 in such a way that the proportion of radiation that penetrates into other components of the laser system, such as the laser optics, is reduced or eliminated. This increases the process reliability and the precision of the laser beam. The service life of the jet nozzle 1 and the laser system is also increased. The improved properties of the jet nozzle 1 due to the absorption surface enable welding behavior without the aforementioned deficiencies.

14 shows a further embodiment of the jet nozzle 1. The nozzle mouth 6 has a bevel 50, by which a part of the nozzle mouth 6 is cut off. The bevel 50 causes the powder section 11 and the powder section-free feed section 12, which optionally forms the process gas unit 60, to be cut off in the circumferential direction around the light channel 3. The bevel 50 reduces the volume of the nozzle mouth 6 compared to the embodiment in which there is no bevel 50. This ensures that the nozzle mouth 6 has a reduced installation space occupies. The jet nozzle 1 with the bevel 50 can be used, for example, to coat a brake disk. The brake disk can have a holder that protrudes axially from the functional surface to be coated. The bevel 50 ensures that the jet nozzle 1 can be moved flexibly on the functional surface to be coated and can be moved close to the holder. The bevel 50 can be essentially flat and run in a plane that is inclined with respect to the longitudinal direction of the jet nozzle. The bevel 50 represents a boundary surface of the nozzle mouth 6 in which no powder unit 7 is provided. In the distal region 8, the bevel 50 is arranged so close to the light channel 3 that no injector guides 19 or additional injectors are provided on an end face of the jet nozzle 1 facing the workpiece in the region of the bevel 50.

15 shows the jet nozzle 1 with the bevel 50 in a top view. The bevel 50 can run in the distal area 8 in the manner of a passante 51 on the elongated hole. The passante 51 defines the orientation of the bevel 50 on the nozzle mouth 6. The passante 51 runs in the front surface of the jet nozzle 1 facing the workpiece along a straight line or an elongated arc that neither intersects nor touches the elongated hole. The distance of the passante 51 from the center 20 of the light channel 3 is greater than the distance of the corresponding section of the elongated hole from the center 20 of the light channel 3. The distance between the passante 51 and an outer edge of the elongated hole is selected such that the wall thickness between them ensures sufficient strength and resilience of the jet nozzle 1.

The orientation of the passante 51 and thus the orientation of the bevel 50 on the nozzle mouth 6 can be varied for different jet nozzles 1 depending on the respective field of application. For example, the passante 51 can run in the feed direction 2. In this case, the passante 51 runs along the extension of the cross-sectional area of the light channel 3. The passante 51 thus runs along the long side of the elongated hole. Alternatively, the passante 51 can run, for example, transversely to the feed direction 2. In this case, the passante 51 runs transversely to the extension of the cross-sectional area of the light channel 3. The passante 51 thus runs along the partial circle section of the elongated hole. Further alternatively, the passante 51 can, for example, run at an angle to the feed direction 2 that lies between a course along the feed direction 2 and transversely to the feed direction 2. In this case, the passante 51 runs along the transition section between the long side of the slot and the partial circle section of the slot. The course of the passante 51 determines the orientation of the bevel 50.

In the embodiment in 15 Outlet openings 62 are provided on the front side of the jet nozzle. The process gas exits from the process gas unit 60 through these. In the present case, the bevel 50 is such that the portion of the nozzle mouth 6 cut off by it originates entirely from the powder section 11, so that the angle along which the powder section 11 extends is reduced by the bevel 50, while the angle along which the process gas unit 60 extends remains essentially the same.

Where applicable, all individual features shown in the embodiments can be combined and/or exchanged without departing from the scope of the invention.

List of reference symbols

1

Jet nozzle

2

Feed direction

3

Light channel

4

Shell surface

5

External structure

6

Nozzle mouth

7

Powder unit

8

distal area

9

Flange section

10

proximal area

11

Powder section

12

Feed section

13

Coolant inlet

14

Coolant outlet

15

Coupling ring

16

Powder injector

17

Inlet nozzle

18

Drain nozzle

19

Injector guide

20

Center of the light channel

21

first powder focus

26

Wrap angle

30

Cooling system

31

radial inner cooling chamber

32

transition

33

radial outer cooling chamber

34

Honeycomb structure

40

Absorption section

50

Bevel

51

Passerby

60

Process gas unit

61

Process gas section

62

Outlet opening

63

Feed opening

64

Distribution arm

65

first steam flare

66

second steam flare

100

workpiece

110

laser beam

111

Primary beam

112

Secondary beam

120

powdered filler material

130

Melt bath

140

Functional layer

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 102011100456 A [0002]
• DE 102018130798 A1 [0002]
• CN109175372A [0002]

Claims (15)

Jet nozzle (1) for laser deposition welding along a feed direction (2), comprising - a light channel (3) for guiding at least one laser beam that is directed at a workpiece; - a powder unit (7) arranged radially outside the light channel (3) for guiding at least one powder jet that is to be applied to the workpiece, wherein the powder unit (7) forms a powder section (11) in a circumferential direction around the light channel (3); and - a process gas unit (60) arranged radially outside the light channel (3) for guiding a process gas, wherein the process gas unit (60) forms a process gas section (61) in the circumferential direction; wherein the process gas section (61) adjoins the powder section (11) at a nozzle mouth (6) in the circumferential direction. Jet nozzle (1) after Claim 1 , wherein the process gas unit (60) forms at least one outlet opening (62) on an end face of the jet nozzle (1), from which the process gas can be guided to the workpiece, wherein in particular in the at least one outlet opening (62) an additional injector for supplying the process gas without additional material is arranged. Jet nozzle (1) according to one of the preceding claims, wherein the process gas section (61) extends at least in sections along a slotted hole arc, in particular in an arc shape, around the light channel (3). Jet nozzle (1) according to one of the preceding claims, wherein the process gas section (61) extends in the circumferential direction around the light channel (3) by a wrap angle (23) between 5° and 180°, in particular between 45° and 120°, relative to a center point (20) of the light channel (3). Jet nozzle (1) according to one of the preceding claims, wherein the process gas section (61) and the powder section (11) together completely surround the light channel (3) in the circumferential direction. Jet nozzle (1) according to one of the preceding claims, wherein the process gas unit (60) has a supply opening (63) through which the process gas can be supplied to the process gas unit (60), and at least one outlet opening (62) through which the process gas exits the process gas unit (60). Jet nozzle (1) after Claim 6 , wherein the process gas unit (60) has several, in particular three, outlet openings (62), each of which is connected to the one supply opening (63). Jet nozzle (1) according to one of the preceding claims, wherein the process gas section (61) is formed in a region of the nozzle mouth (6) facing the feed direction (2). Jet nozzle (1) according to one of the preceding claims, wherein the powder section (11) has a plurality of injector guides (19), into each of which a powder injector (16) can be inserted. Jet nozzle (1) after Claim 9 , wherein an inner diameter of the at least one outlet opening (62) is smaller than an inner diameter of the injector guides (19). Jet nozzle (1) according to one of the Claims 9 or 10 , wherein a first powder injector is prepared to convey a first powder mass flow and a second powder injector is prepared to convey a second powder mass flow, wherein the first powder mass flow deviates from the second powder mass flow. Jet nozzle (1) according to one of the preceding claims, wherein the powder section (11) forms an annular gap segment. Jet nozzle (1) according to one of the preceding claims, wherein the light channel (3) is adapted to guide a plurality of laser beams, the plurality having a first laser beam as a primary beam (111) and a second laser beam as a secondary beam (112). Jet nozzle (1) according to one of the preceding claims, which is produced by means of an additive manufacturing process and consists in particular of copper or a copper alloy, more particularly a copper-chromium-zirconium alloy. Jet nozzle (1) according to one of the preceding claims, wherein the nozzle mouth (6) has a bevel (50) by which a part of the nozzle mouth (6) is cut off, wherein the bevel (50) is designed essentially flat and runs in a plane which is inclined with respect to the longitudinal direction of the jet nozzle (1).

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