Jet nozzle having a powder unit and a process-gas unit

Abstract

The present invention relates to a jet nozzle (1) for laser deposition welding in an advance direction (2), comprising a light channel (3) for guiding at least one laser beam directed at a workpiece; a powder unit (7) disposed 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 portion (11) in a peripheral direction around the light channel (3); and a process-gas unit (60) disposed radially outside the light channel (3) for guiding a process gas, wherein the process-gas unit (60) forms a process-gas portion (61) in the peripheral direction, wherein the process-gas portion (61) adjoins the powder portion (11) at a nozzle mouth (6) in the peripheral direction.

Description

[0001] Blasting nozzle with powder unit and process gas unit

[0002] Technical area

[0003] The present invention relates to a jet nozzle for laser cladding along a feed direction.

[0004] State of the art

[0005] 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 published patent applications DE 10 2011 100 456 A and DE 10 2018 130 798 A1. Another laser cladding process is known from the Chinese patent application CN 109175372 A.

[0006] Laser cladding can be used to apply a functional layer to a workpiece. This layer generally increases the load-bearing capacity of the workpiece processed using laser cladding compared to an unmachined workpiece. The functional layer can serve, for example, as a wear-resistant layer. The application of the functional layer is based on melting a workpiece surface, applying a powdered filler material, and subsequent cooling, so that a matrix structure with hard material particles is firmly bonded to the material surface. Laser cladding thus intervenes in the internal material structure of the workpiece and changes it. This can potentially 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 are only identifiable with great effort.

[0007] Description of the invention Starting from 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 weld quality of an applied functional layer and of the workpiece as a whole and to reduce or avoid deficiencies in a weld joint between a powdered filler material and a material surface. The deficiencies can be lack of bonding 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 may occur more frequently, particularly if the material surface is a cast material. The deficiencies may also include cracks, which run particularly vertically to the material surface within the applied functional layer. The deficiencies may also arise from powder particles, particularly 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 blasting nozzle that is resistant to thermal stress. The invention may further aim to design the blasting nozzle in such a way that it ensures reliable and precise laser cladding over very high cycle numbers.

[0008] The problem is solved by a jet nozzle having the features of claim 1. Advantageous further developments emerge from the subclaims, the description, and the figures.

[0009] Accordingly, a beam nozzle for laser material deposition along a feed direction is proposed, which has a light channel for guiding at least one laser beam directed at a workpiece. Laser material deposition can be a process for high-speed laser material deposition (HS-LMD). The feed direction is the direction along which the beam 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 beam nozzle, or from a superposition of both movements. The feed direction and the correlating feed movement can be constant throughout the process. Alternatively, they can vary with the respective process stage. The workpiece can be a rotationally symmetrical workpiece, such as a brake disc, a hydraulic cylinder, a printing roller, or a plain bearing.The laser beam can pass through the light channel. It can be provided by a laser source, from which the laser beam is guided via a fiber optic cable to a laser system that splits the laser beam using a collimating lens and focuses it using laser optics for the process before it enters the jet nozzle. The light channel can be a hollow channel that runs longitudinally through the entire jet nozzle. In addition to the laser beam, a process gas can also be guided to the workpiece surface through the light channel.

[0010] The blasting nozzle further comprises a powder unit arranged radially outside the light channel for guiding at least one powder jet to be applied to the workpiece, wherein the powder unit forms a powder section in a circumferential direction around the light channel. The powder unit can be arranged radially outside the light channel, starting from the longitudinal direction of the blasting nozzle, and can be part of an external structure that encloses the light channel. The powder jet can guide a powdered filler material consisting of hard material particles, in particular carbides, and a matrix material. The powder unit can be the part of the blasting nozzle that is intended to guide the powdered filler material directly or indirectly. The powder unit can comprise injector guides into which powder injectors can be inserted. It can also comprise an annular gap within which the powdered filler 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. At 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 plan view, the powder section can run at least partially along an opening of the light channel.

[0011] The jet nozzle further comprises a process gas unit arranged radially outside the light channel for guiding a process gas, wherein the process gas unit forms a process gas section in the circumferential direction. The process gas unit can be arranged radially outside the light channel, starting from the longitudinal direction of the jet nozzle, and can be part of the external structure that encloses the light channel. The process gas can positively influence the powder causticity 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 comprise injector guides into which additional injectors can be inserted. It can also comprise 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 orifice. In plan view, the process gas section can extend at least partially along the opening of the light channel. The process gas section can be the part of the process gas unit from which the process gas exits the jet nozzle.

[0012] The process gas section adjoins the powder section at the nozzle orifice in the circumferential direction. Thus, the process gas section is directly adjacent to the powder section in the circumferential direction. This allows the process gas to have a stabilizing effect on the powder caustic and the ongoing laser cladding. The process gas section can adjoin the powder section in such a way that a transition occurs 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 exterior. This can contribute to stabilizing the process zones and simultaneously prevent powder particles from adhering to one end face of the jet nozzle, thus increasing the service life of the jet nozzle.

[0013] The jet nozzle can thus provide increased variability in (i) laser beam guidance, (ii) the application of a powdered filler material, (iii) thermal management, and (iv) the protection of the laser system including the jet nozzle. It enables the provision of multiple 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 laser cladding zones, 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 weld quality and thus the resilience of the applied functional layer, especially the wear-resistant layer, and of the workpiece as a whole. An additional process gas can stabilize the process zones and increase the precision of the laser cladding as well as the service life of the jet nozzle. In particular, the jet nozzle can reduce the occurrence of lack of fusion. Lack of fusion can occur when the surface heated by the laser beam, such as the workpiece or a previously welded functional layer, has not been sufficiently heated. This lack of heating can be the result of the laser power of an individual laser beam being kept low to avoid overheating of the powdered filler 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 occurrence of fusion defects 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.

[0014] In particular, the blasting 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, especially graphite lamellae, evaporate due to the laser radiation. Pores can also occur if the surface to be machined contains contaminants, for example, caused by oils, greases, cooling lubricants, or oxides, which cannot be completely removed by the welding process. The undesired evaporation of contaminants can be the result of the laser power of an individual laser beam being set so high that fusion defects due to insufficient heating can be avoided.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 occurrence of pores 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.

[0015] In particular, the blasting nozzle can reduce the occurrence of cracks in the welded functional layer. Cracks can occur when the temperature gradient between the highly heated powdered filler material and the less heated workpiece surface is so strong that material shrinkage occurring during cooling leads to crack-causing stresses. Crack formation can be the result of setting the laser power of a single laser beam so high that fusion defects due to insufficient heating can be avoided.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 occurrence of cracks 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 caustic.

[0016] Furthermore, the blasting nozzle can particularly reduce the dissolution of hard material particles, in particular carbides, in the matrix material. The powdered filler 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 filler material is exposed to an excessively high irradiation intensity, causing the hard material particles to melt. Dissolved hard material particles cause the welded functional layer to become brittle because the matrix material is less ductile, meaning that stresses arising, for example, from shrinkage during cooling or loading of the workpiece 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 caustic.

[0017] In particular, the blasting nozzle can prevent powder particles from adhering to the nozzle orifice. Due to the high process heat, reflected laser radiation and / or metal vapor flare can cause filler material to adhere or even fuse to the nozzle orifice, disrupting the gas and powder flows and subsequently impairing the process outcome. Metal vapor flare is a result of the partial evaporation of the material during laser cladding. It can lead to scattering and / or absorption of laser radiation and subsequently impair preheating of the workpiece. This can further promote the formation of fusion defects.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 undesired 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 caustic.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 orifice in such a way that, in interaction with the powdered filler material, more than one process zone is formed. This promotes the welding behavior and reduces deficiencies in the weld joint, in particular the occurrence of lack of fusion, 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 orifice is prevented. Secondly, the spread of the vapor flare can be prevented by keeping it in the area between the nozzle orifice and the workpiece, in particular within the powder section and the process gas section.Thus, the process gas section contributes to reducing the aforementioned deficiencies.

[0018] In one embodiment, the process gas unit forms at least one outlet opening on an end face of the jet nozzle, from which the process gas can be guided to the workpiece, wherein an additional injector for supplying the process gas without additional material is arranged in particular in the at least one outlet opening. The outlet opening can be designed on the end face in such a way that the area to which hard material particles can adhere is minimized. The process gas guided from the outlet opening can be supported by the process gas guided within the light channel. An additional injector can be arranged in each outlet opening. The additional injector differs from the injectors 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.

[0019] In one embodiment, the process gas section extends at least partially along a slotted hole arc, in particular in an arc shape, around the light channel. Analogous to a circular arc, the slotted hole arc represents a line surrounding the slotted hole in a sector. The remaining part of the slotted hole, which is not encompassed by the slotted hole 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 lies at the front in the feed direction, to form the arc shape. This further contributes to stabilizing the laser beam guidance and / or the powder caustic.

[0020] In one embodiment, the process gas section extends circumferentially around the light channel at a wrap angle of between 5° and 180°, in particular between 45° and 120°, relative to a center point of the light channel. Thus, the process gas section can extend around the light channel for a smaller distance than the powder section. This ensures satisfactory powder supply through the powder unit, and in particular the injectors arranged therein, while preventing adhesion or the spread of the vapor flare. Precise adaptation of the powder section and the process gas section to the respective process conditions enables efficient welding behavior without deficiencies.

[0021] 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, which forms within the beams, from an exterior, which 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 escape from the interior, preventing undesirable interaction of the vapor flare with the workpiece.

[0022] In one embodiment, the process gas unit has a supply opening through which the process gas can be supplied 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 supply opening can be coupled to a supply hose that guides the process gas from a gas reservoir to the jet nozzle. The process gas unit can have exactly one supply opening. The at least one outlet opening is fluidically connected to the supply opening and has a shape that ensures that the process gas exits in the direction of the workpiece surface in a process-appropriate manner. At least one distribution arm that guides the process gas is provided between the supply opening and the at least one outlet opening. An additional injector can be provided in the distribution arm and / or in the outlet opening.Alternatively, the process gas can exit directly from the distribution arm and / or the outlet opening.

[0023] In one embodiment, the process gas unit has several, in particular three, outlet openings, each 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, a curved 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 vapor flare and preventing powder particles from adhering to the nozzle orifice.

[0024] 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.

[0025] In one embodiment, the powder section has a plurality of injector guides, each of which can accommodate a powder injector. The injector guides can be cylindrical or conical through-openings in the area of ​​the nozzle mouth, each of which can accommodate a powder injector. The injector guides can be machined into the nozzle mouth. However, they are preferably already provided during 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.

[0026] 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 flowing out of the powder injectors in the injector guides and of process gas flowing out of the at least one outlet opening can be essentially the same. It is also possible for process gas to flow out of the light channel in addition to the outlet openings. The gas flow rates of conveying gas and process gas can also be weighted relative to one another. 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 adjusted depending on the process.

[0027] In one embodiment, a first powder injector is configured to convey a first powder mass flow, and a second powder injector is configured 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, and the second powder injector can be provided 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 different energies. 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 exiting the at least one outlet opening can be adjusted according to the first powder mass flow of the second powder mass flow.

[0028] In one embodiment, the powder section forms an annular gap segment, particularly instead of injector guides. The annular gap segment can form a uniform powder focus, which, for example, coincides with the center of the at least one laser beam. In the annular gap segment, the powdered additional material is applied to the workpiece along a horseshoe-shaped beam.

[0029] In one embodiment, the light channel is adapted to guide a plurality of laser beams, wherein the plurality has 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 fiber optic cable. A provided laser light can be split into a parallel beam bundle using a collimating lens. The beam bundle can, for example, form the primary beam and the secondary beam from a single laser beam using a wedge plate. 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 a line from a center of the light channel in the feed direction.

[0030] In one embodiment, the jet nozzle is manufactured using an additive manufacturing process, in particular 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 additive manufacturing processes on the one hand and ensures sufficient strength, thermal conductivity, and heat resistance to withstand the process requirements on the other. In powder bed melting, the material to be processed is in powder form. A laser beam heats the powder along the intended geometry, liquefying the powder and bonding it together. Powder bed melting can, for example, be implemented as selective laser melting ("SLM") or selective laser sintering ("SLS").In one embodiment, the nozzle mouth has a bevel by which a portion 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 feed section free of powder sections 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. Thus, the nozzle mouth takes up less installation space. The jet nozzle with the bevel can be used, for example, to coat a brake disc that has a receptacle that protrudes axially relative to the functional surface to be coated.The bevel ensures that the jet nozzle can move flexibly over the functional surface to be coated and can be moved close to the holder. In the distal area, the bevel can run like a passante on the elongated hole. The passante defines the orientation of the bevel at the nozzle mouth. The passante runs on the end face of the jet nozzle facing the workpiece along a straight line or an arc that neither intersects nor touches the elongated hole. The distance of the passante from the center of the light channel is greater than the distance of the corresponding section of the elongated hole from the center of the light channel. The distance between the passante and an outer edge of the elongated hole is selected such that the wall thickness in between ensures sufficient strength and load-bearing capacity of the jet nozzle.

[0031] 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 at a radially outer portion for shielding a process zone.

[0032] The features disclosed contribute, partly individually and partly in combination, to overcoming the deficiencies in laser cladding mentioned at the outset.

[0033] Short description of the characters

[0034] Preferred further embodiments of the invention are explained in more detail in the following description of the figures. In the figures:

[0035] Figure 1 is a schematic view of a jet nozzle in laser cladding;

[0036] Figure 2 shows a jet nozzle in a side view; Figure 3 shows the jet nozzle from Figure 2 in a perspective view;

[0037] Figure 4 shows the jet nozzle from Figure 2 connected to other components;

[0038] Figure 5 shows the jet nozzle from Figure 2 in a plan view of a distal region;

[0039] Figure 6 shows the jet nozzle from Figure 2 in a plan view of a flange section;

[0040] Figure 7 is a further perspective view of the jet nozzle from Figure 2;

[0041] Figure 8 is a perspective sectional view of the jet nozzle of Figure 2;

[0042] Figure 9 shows the jet nozzle with a process gas unit in a plan view of the distal area;

[0043] Figure 10 shows 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;

[0044] Figure 11 the jet nozzle with the process gas unit in a perspective view;

[0045] Figure 12 the jet nozzle with the process gas unit in a side view;

[0046] Figure 13 further representations of the jet nozzle with the process gas unit;

[0047] Figure 14 shows a further embodiment of the jet nozzle with a geometrically adapted nozzle mouth in a side view; and

[0048] Figure 15 shows a further embodiment of the jet nozzle with a geometrically adapted nozzle mouth in a plan view.

[0049] Detailed description of preferred embodiments

[0050] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the different figures are provided with identical reference numerals, and a repeated description of these elements is partially omitted to avoid redundancies.

[0051] Figure 1 shows a jet nozzle 1 for laser material deposition 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 throughout the process. Alternatively, they can vary with the respective process stage. The workpiece 100 can be a rotationally symmetrical workpiece, such as a brake disc, a hydraulic cylinder, a printing 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 at a radially outer section to shield a process zone and prevent oxidation. The light channel 3 is surrounded by an outer structure 5 having 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 Figure 3), into each of which a powder injector 16 (see Figure 4) can be inserted. As an alternative to the individual injector guides 19, the powder unit 7 can have a powder annular gap channel. A powdery filler 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 such that a melt pool 130 forms on a material surface.In addition, the laser beam 110 heats the powdered filler material 120, which comprises hard material particles and a matrix material. For this purpose, the laser beam 110 can have a reduced core intensity. As the molten pool 130 cools, a welded functional layer 140, for example, a wear-resistant layer, forms 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.

[0052] Figure 2 shows the jet nozzle 1 in a side view, with the feed direction 2 pointing 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 a component of the funnel-shaped nozzle mouth 6. This has, in a circumferential direction around the light channel 3, a powder section 11 in which the powder unit 7 is arranged.Adjoining the powder section 11 in the circumferential direction is a feed section 12 free of a powder unit. The feed section 12 can be designed as a process gas section 61 (see, for example, Figure 9), which is a component of a process gas unit 60. Figure 3 shows the jet nozzle from Figure 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 an essentially 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 Figure 4) is inserted into each of these injector guides 19, which directs the powdered filler material 120 onto the at least one laser beam 110 and / or the workpiece 100 in a process-appropriate manner. The powder unit 7 extends along the powder section 11, which is adjoined in the circumferential direction by the powder unit-free feed section 12. The feed section 12 is the region of the nozzle mouth 6 in which no injector guides 19 are provided, so that no powdered filler material 120 is fed through it. In one embodiment, the feed section 12 can be shaped 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 methods, in particular using powder bed melting. For this purpose, the jet nozzle 1 can be made of a copper-chromium-zirconium alloy.This is suitable for additive manufacturing processes 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, liquefying the powder and bonding it together. Powder bed melting can be implemented, for example, as Selective Laser Melting ("SLM") or Selective Laser Sintering ("SLS").

[0053] Figure 4 shows the blasting nozzle 1 with additional components attached. A coupling ring 15 is connected to the flange section 9, which secures the blasting 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 powder injectors 16 convey the powdered filler material 120 and apply it to the workpiece 100 with the intended focus. The individual powder injectors 16 can apply different powder foci. Alternatively, the powder injectors 16 can be directed at the same focal 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. Figure 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 like an elongated hole, with a partial circular section adjoining 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 provided laser light can be split into a parallel beam bundle using a collimating 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 from a center point 20 of the light channel 3.

[0054] In this 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 strike 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 defect-free 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.Thus, the secondary beam 112 can be used to reheat the workpiece 100 and thus contribute to a more uniform cooling, which prevents the occurrence of inclusions or other imperfections.

[0055] 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 with the secondary beam 112, while the rear partial circle section of the elongated hole is concentric with the primary beam 111. A center 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 unshielded from one another, so that there is exactly one light channel 3 with exactly one lateral surface 4, which results in minimal thermal losses.

[0056] Because the primary jet 111 in Figure 5 is arranged behind the secondary jet 112 in the feed direction 2 without any radial offset, and the secondary jet 112 serves to preheat the workpiece, it is desirable that the powdered filler 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 filler material is only heated by the primary jet 111 and not by the secondary jet 112. This is achieved by the jet nozzle 1 shaping 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, to which the powder unit-free feed section 12 is connected in the circumferential direction.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 that 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°, further in particular between 180° and 300°, relative to a center point of the light channel.This ensures that the powdered filler material flowing out of the injectors 16, which are inserted into the injector guides 19, interacts only with the primary jet 111. The secondary jet 112 can thus form a process zone independent of the primary jet 111. The powder section 11 and the feed section 12 form a slotted hole in plan view. This further contributes to reducing or avoiding the deficiencies identified above.

[0057] Figure 6 shows the jet nozzle 1 in a plan 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 region 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 region 8 to the flange section 9. In the region of the nozzle mouth 6, the cross-sectional area can be elongated such 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 plan view of the proximal region 10.

[0058] Figure 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 elongated in a manner deviating from a circular shape in order to achieve the advantages disclosed. 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 adjoined by the powder-free feed section 12.

[0059] Figure 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, which runs 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. Figure 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 fed back 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 orifice 6. The radially inner cooling chamber 31 is formed at least in the nozzle orifice 6. It can run from the distal region 8 to the proximal region 10 and be designed in the manner of an annular gap segment that extends circumferentially around the light channel 3. In the region of the nozzle orifice 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 orifice 6 and is concentric with the light channel 3 in a cross-sectional area extending orthogonally to a longitudinal direction of the jet nozzle 1.

[0060] 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, whereby sufficient installation space is available for the transition 32.

[0061] 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 during the return from the distal region 8 to the proximal region 10, thus promoting heat dissipation. The cooling structure is optimized to minimize pressure losses of the cooling medium. This can be achieved using a honeycomb structure 34, as shown in Figure 8.

[0062] Figure 9 shows the jet nozzle 1 in a plan view of the distal region 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 described in more detail in connection with Figure 5. During the interaction of the laser beams with the material surface and the powder jet, a vapor flare can form between the jet nozzle 1 and the workpiece 100. If this vapor flare is not contained, it can interact in an undesirable manner with the at least one laser beam and / or the unprocessed and / or processed material surface. In the region adjoining 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, which is arranged radially outside the light channel 3 and directs the process gas onto the workpiece. The process gas section 61 can prevent undesired propagation of the vapor flare and thus contribute to precise workpiece machining with a robust jet nozzle design. The process gas section 61 can form at least one, in this case three, outlet openings 62. The outlet openings 62 are formed on an 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 end face 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 arranged circumferentially around the elongated hole formed by the light channel 3. Thus, the primary beam 111 and the secondary beam 112 are completely within the beams composed of the powder jet and the process gas jet.

[0063] 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 flowing out of the injectors 16 or the injector guides 19 and of process gas flowing 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 relative to one another. 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.

[0064] Figure 10 shows the view from Figure 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° for completely enclosing the light channel 3 are formed in this case by the process gas section 61. Thus, the powder jet and the process gas jet 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 .

[0065] Figure 11 shows a perspective view of the jet nozzle 1. A supply opening 63 is provided in the process gas section 60. The supply opening 63 is arranged in the area of ​​the nozzle mouth 6 facing away from the workpiece. Process gas is supplied to the process gas section 60 via this opening. Starting from the one supply opening 63, the process gas can be guided to the individual outlet openings 62 through distribution arms 64 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 supply 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 in such a way that the process gas can be directed onto the workpiece surface efficiently and in a process-appropriate manner.

[0066] Figure 12 shows the blasting nozzle 1, the workpiece 100, and the area in between in a side view. The powder unit 7 extends such that the powder jet can be directed from the powder section 11 of the nozzle mouth 6 onto the workpiece 100 in a process-appropriate manner. 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 a process-appropriate manner. The interaction between the primary jet 111, the powder jet, and the workpiece surface creates a first vapor flare 65. The interaction between the secondary jet 112 and the material surface creates a second vapor flare 66.The process gas flows from 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.

[0067] Figure 13 shows the jet nozzle 1 in three different views. Figure 13 a) is a perspective view. In the area of ​​the nozzle orifice 6 facing the flange section 9, the supply opening 63 is provided in the process gas unit 60. This represents the central interface through which process gas is supplied to the nozzle orifice 6. Starting from the supply opening

[0068] 63, the process gas is distributed along the distribution arms 64, which distribute the process gas from the supply 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 toward the workpiece. The outlet openings 62 are part of the process gas section 61 and 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.

[0069] Figure 13 b) is a sectional view. The powder unit 7, which forms the powder section 11 and through which the injector guides 19 extend, is provided at a rear area in the feed direction 2. The injector guides 19 are each adapted to accommodate a powder injector 16. The process gas unit 60, which forms the process gas section 61 and through which the distribution arms extend, is provided at a front area in the feed direction 2.

[0070] 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 lateral surface 4 of the light channel 3 for absorbing reflection radiation of the laser beam from the workpiece 100. The absorption section 40 can have a geometry that favors the absorption of the reflection radiation.The absorption section can extend variably in a circumferential direction around the light channel 3, in particular, be configured over 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 lateral surface of the nozzle mouth 6, but rather a smooth inner end section in order to better clean the inside of the nozzle mouth 6. The shape of the absorption section 40 can be adapted to the expected reflected radiation. The absorption section 40 can be formed from 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 dissipated by the cooling system 30.The reflected radiation is absorbed by the absorption section 40 in such a way that the portion of radiation that penetrates other components of the laser system, such as the laser optics, is reduced or eliminated. This increases process reliability and the precision of the laser beam.

[0071] 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.

[0072] Figure 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 no bevel 50 is present. This ensures that the nozzle mouth 6 occupies a smaller installation space. The jet nozzle 1 with the bevel 50 can be used, for example, to coat a brake disc. The brake disc can have a receptacle that protrudes axially relative to 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 substantially flat and extend in a plane that is inclined relative to the longitudinal direction of the jet nozzle. The bevel 50 represents a boundary surface of the nozzle orifice 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.

[0073] Figure 15 shows the jet nozzle 1 with the bevel 50 in a top view. The bevel 50 can run in the distal region 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 end face 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 point 20 of the light channel 3 is greater than the distance of the corresponding section of the elongated hole from the center point 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 therebetween ensures sufficient strength and load-bearing capacity of the jet nozzle 1.

[0074] 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 a course 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 pitch circle section of the slot. The course of the passante 51 determines the orientation of the bevel 50.

[0075] In the embodiment shown in Figure 15, outlet openings 62 are provided on the end face of the jet nozzle. The process gas exits from these openings from the process gas unit 60. In the present case, the bevel 50 is such that the portion of the nozzle orifice 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 substantially the same.

[0076] Where applicable, all individual features presented in the embodiments may be combined and / or interchanged without departing from the scope of the invention.

[0077] 1 jet nozzle 30 cooling system

[0078] 2 Feed direction 25 31 radial inner cooling chamber

[0079] 3 Light channel 32 Transition 4 Shell surface 33 Radial outer cooling chamber

[0080] 5 Outer structure 34 Honeycomb structure

[0081] 6 Nozzle mouth 40 Absorption section

[0082] 7 Powder unit 30 50 bevel

[0083] 8 distal area 51 passer-by 9 flange section 60 process gas unit

[0084] 10 proximal area 61 process gas section

[0085] 11 Powder section 62 Outlet opening

[0086] 12 Feed section 35 63 Feed opening

[0087] 13 Coolant inlet 64 Distribution arm 14 Coolant outlet 65 First steam flare

[0088] 15 Coupling ring 66 second steam flare

[0089] 16 Powder injector 100 Workpiece

[0090] 17 Inlet nozzle 40 110 laser beam

[0091] 18 Drain nozzle 111 Primary jet 19 Injector guide 112 Secondary jet

[0092] 20 Center of the light channel 120 powdered filler material

[0093] 21 first powder focus 130 melt pool

[0094] 26 Wrap angle 45 140 Functional layer

Claims

Claims 1. A jet nozzle (1) for laser material deposition along a feed direction (2), comprising a light channel (3) for guiding at least one laser beam directed onto a workpiece; a powder unit (7) arranged radially outside the light channel (3) for guiding at least one powder jet 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.

2. Jet nozzle (1) according to 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 outlet opening 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.

3. Jet nozzle (1) according to one of the preceding claims, wherein the process gas section (61) extends at least partially along an elongated hole arc, in particular in an arc shape, around the light channel (3).

4. 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).

5. 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.

6. 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).

7. Jet nozzle (1) according to 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).

8. 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).

9. 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.

10. Jet nozzle (1) according to 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).

11. Jet nozzle (1) according to one of 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 differs from the second powder mass flow.

12. Jet nozzle (1) according to one of the preceding claims, wherein the powder section (11) forms an annular gap segment.

13. 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).

14. Jet nozzle (1) according to one of the preceding claims, which is manufactured by means of an additive manufacturing process and consists in particular of copper or a copper alloy, more particularly a copper-chromium-zirconium alloy.

15. Jet nozzle (1) according to one of the preceding claims, wherein the nozzle mouth (6) has a bevel (50) through which a part of the nozzle mouth (6) is cut off, wherein the bevel (50) is substantially flat and extends in a plane which is inclined with respect to the longitudinal direction of the jet nozzle (1).

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