Powder injector with a positioning portion and a stop portion, spray nozzle with an inner wall, and system having a spray nozzle and powder injectors

Abstract

The present invention relates to a powder injector (1) for use in an injector guide (101) of a spray nozzle (100) for laser cladding, having an injector tip (3) located at the front in a powder conveying direction (2) and a tube interface (4) located at the rear in the powder conveying direction (2); wherein the injector tip (3) has a positioning portion (5) in which an outer wall (6) of the powder injector (1) is inclined with respect to the powder conveying direction (2) by a positioning chamfer (7), and has a stop portion (8) adjacent to the positioning portion (5) in the powder conveying direction (2), in which stop portion an outer wall (9) of the powder injector (1) is inclined with respect to the powder conveying direction (2) by a stop chamfer (10) which differs from the positioning chamfer (7) and which is less than 90°. The invention also relates to a spray nozzle and to a system having a spray nozzle and a powder injector.

Description

[0001] Powder injector with a positioning section and a stop section, blasting nozzle with an inner wall and system with a blasting nozzle and powder injectors

[0002] Technical area

[0003] The present invention relates to a powder injector for use in an injector guide of a jet nozzle for laser cladding, a jet nozzle for laser cladding and a system with a jet nozzle and a plurality of powder injectors.

[0004] State of the art

[0005] Laser cladding is used in repair, coating, and / or joining technology, for example. 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, for example, in the form of extreme high-speed laser cladding (EHLA)). HS-LMD processes are described, for example, in published patent applications DE 102011 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] 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 unmachined workpiece. The functional layer can serve, for example, as a wear-resistant layer. The application of the functional layer can be based on a diffusion process, partial melting and / or melting of a workpiece surface, the application of a filler material, and subsequent cooling, so that a matrix structure with hard material particles is firmly bonded to the material surface. Laser cladding influences and changes the internal material structure of the workpiece and the material being deposited. Description of the invention

[0007] The object of the invention is to provide an improved powder injector for use in an injector guide of a jet nozzle for laser cladding, an improved jet nozzle for laser cladding, and / or an improved system comprising a jet nozzle and a plurality of powder injectors. In particular, the invention aims to enable more precise and / or closer-tolerance application of a powder jet to a workpiece. The invention may also aim to facilitate the installation of a powder injector in an injector guide and / or to increase the robustness of the jet nozzle. Ultimately, the invention may also aim at higher-quality application of the functional layer.

[0008] The problem is solved by a device having the features of the independent claims. Advantageous further developments emerge from the dependent claims, the description, and the figures.

[0009] Accordingly, a powder injector for use in an injector guide of a jet nozzle for laser material deposition welding is proposed. The powder injector delivers a powder jet containing at least one powdered filler material consisting of hard material particles, in particular carbides, and a matrix material. The powdered filler material leaves the powder injector as a powder jet, which is applied to a workpiece in interaction with a laser beam to form a functional layer. On the side of the powder injector facing away from the workpiece, the powdered filler material is fed to the powder injector via a hose and / or a powder feed line. The jet nozzle can have a light channel for guiding at least one laser beam directed onto the workpiece.Furthermore, the jet nozzle can have a powder unit arranged radially outside the light channel for guiding at least one powder jet in a powder conveying direction. The powder unit can have a plurality of injector guides in a circumferential direction of the jet nozzle, into each of which a powder injector is inserted. The plurality of injector guides can extend at least partially around the light channel in the circumferential direction. For example, the injector guides are arranged around the light channel in the manner of a partial circle. The powder injector can be inserted into an injector guide with a positive fit. In addition, the powder injector can be locked in the injector guide with a force fit.

[0010] The powder injector has an injector tip located at the front in the powder feed direction and a hose interface located at the rear in the powder feed direction. The powder feed direction indicates the direction along which the powdered filler material is fed through the powder injector. It corresponds to a longitudinal axis of the powder injector, which, if the powder injector is rotationally symmetrical, corresponds to the axis of rotation. The powder feed direction corresponds to the longitudinal axis of the injector guide. The injector tip is a section of the powder injector that faces the workpiece. The injector tip can be less than a tenth of the length of the powder injector. The injector tip is the section of the powder injector facing the machining location, which is why it is exposed to the highest thermal stress. At the injector tip, the powdered filler material leaves the powder injector as a powder jet from an outlet opening.The hose interface is a section of the powder injector facing away from the workpiece. The hose interface can be less than one-twentieth the length of the powder injector. The powder filler material is fed to the powder injector at the hose interface.

[0011] The injector tip has a positioning section in which an outer wall of the powder injector is inclined relative to the powder conveying direction by a positioning chamfer. Due to the positioning chamfer, the outer diameter of the powder injector decreases in the area of ​​the injector tip. The positioning chamfer facilitates radial positioning of the powder injector in the injector guide. An inner wall of the jet nozzle can be tapered in the powder conveying direction, for example, in the manner of a first section, in order to radially accommodate the positioning section. The positioning chamfer can be machined onto the powder injector.

[0012] The injector tip has a stop section adjoining the positioning section in the powder feed direction, in which an outer wall of the powder injector is inclined relative to the powder feed direction by a stop chamfer that is different from the positioning chamfer and is less than 90°. Due to the stop chamfer, an outer diameter of the powder injector further decreases after the positioning section. The stop chamfer facilitates axial positioning of the powder injector in the injector guide. The inner wall of the jet nozzle can have a stop to axially accommodate the stop section. The stop chamfer can be applied to the powder injector by machining. The fact that the stop chamfer is less than 90° means that an angle between a chord resting on the stop section and the powder feed direction is less than 90°, so that the stop section is pointed in the powder feed direction.

[0013] The interaction between the positioning section and the stop section ensures a separation of functions when inserting the powder injector into the injector guide. The depth stop is realized via the stop section, the radial positioning via the positioning section. The positioning of the powder injector in the blasting nozzle is thus precisely defined, resulting in fewer tolerances. The actual position of the powder injector in the blasting nozzle corresponds essentially to the theoretical position without any tolerances, which enables more precise and / or closer-tolerance application of the powder jet to a workpiece. Furthermore, the separation of functions ensures efficient assembly of the powder injector, preventing the powder injector from sitting loosely in the injector guide, which can result from static over-determination. In particular, the stop section rests gap-free on a stop of the injector guide.Thanks to the positioning chamfer and the stop chamfer, the powder injector is tapered in the area of ​​the injector tip, requiring less material than a powder injector without a positioning chamfer and stop chamfer. This reduced material leads to reduced thermal stress on the powder injector, as less thermal energy can be transferred from the machining location to the powder injector. This increases the service life of the powder injector. Furthermore, the positioning section provides a beveled shoulder to absorb axial forces, further reducing the minimum distance between the powder injector's outlet opening and the nozzle tip of the jet nozzle.Ultimately, the positioning section with the positioning chamfer makes it possible to eliminate a massive shoulder in the injector guide, which allows the powder injector to be brought closer to the processing location, which increases the precision of the powder jet and thus promotes a higher-quality application of the functional layer.

[0014] In one embodiment, the positioning chamfer lies in a range between 5° and 45°, in particular between 15° and 25°. It has been found that within this angular range, an optimal compromise is achieved between (1) satisfactory radial guidance, (2) sufficient wall thickness of the powder injector to withstand thermal and / or mechanical loads, (3) sufficient absorption of axial forces when the positioning chamfer rests on a corresponding section of the injector guide, (4) efficient production of the injector guide and the powder injector, (5) space utilization in the area of ​​a nozzle mouth of the jet nozzle, and / or (6) bringing the individual powder injectors closer to the processing location. In this respect, the positioning chamfer in this angular range contributes to increasing the efficiency and precision of processing by the powder injector.

[0015] In one embodiment, the stop chamfer lies in a range between 45° and 85°, in particular between 60° and 80°. It has been found that within this angular range, an optimal compromise is achieved between (1) a satisfactory depth stop, (2) sufficient wall thickness of the powder injector to withstand thermal and / or mechanical loads, (3) sufficient absorption of axial forces when the stop chamfer rests on a corresponding stop of the injector guide, (4) efficient production of the injector guide and the powder injector, (5) space utilization in the area of ​​the nozzle mouth of the jet nozzle, and / or (6) bringing the individual powder injectors closer to the processing location. In this respect, the stop chamfer in this angular range contributes to increasing the efficiency and precision of processing by the powder injector.In one embodiment, an inner wall of the hose interface is inclined relative to the powder conveying direction by a hose bevel, which is inclined in particular in a range between 30° and 80°, and further in particular between 40° and 60°. This hose bevel enables a continuous transition between an inner diameter of a powder feed line and an inner diameter of a feed shaft running between the injector tip and the hose interface. Accordingly, reduced turbulence occurs during the transition of the powder-infused filler material from the powder feed line into the powder injector, which favors the flow characteristics of the powder conveyance.

[0016] In one embodiment, the powder injector further comprises the conveyor shaft, which extends along the powder conveying direction between the injector tip and the hose interface to convey a medium, in particular a powder and / or a powder mixture, thus the powdered filler material, through the powder injector. The conveyor shaft has a substantially constant cross-section. The conveyor shaft can have a constant inner diameter and a constant outer diameter. This further promotes the flow properties of the powder conveyance and facilitates the manufacture of the conveyor shaft.

[0017] In one embodiment, the injector tip has a front ring that closes off the stop section in the powder feed direction, the diameter of which exceeds the inner diameter of the feed shaft of the powder injector. The front ring represents the distal boundary of the powder injector, i.e., the boundary facing the workpiece. The fact that the front ring has a diameter that exceeds the inner diameter of the feed shaft promotes the escape of the powder-like filler material from the powder injector, as the geometry of a developing powder jet cone is predetermined. The resulting powder jet cone can be adapted to the intended machining and the intended powder focus via the geometry of the front ring. This promotes the precision of the powder jet machining.

[0018] In one embodiment, the injector tip makes up less than one-tenth of the length of the powder injector along the powder conveying direction. Alternatively or additionally, the hose interface makes up less than one-twentieth of the length of the powder injector along the powder conveying direction. The largest part of the length of the powder injector can thus be formed by the conveying shaft, which promotes efficient conveying of the powdered filler material through the powder injector.

[0019] In one embodiment, the length of the positioning section in the powder conveying direction exceeds the length of the stop section by at least four times. In particular, 90% of the injector tip in the powder conveying direction is formed by the positioning section, and the remaining 10% by the stop section. It has been found that this ratio enables a reliable distribution of the respective functions. Furthermore, a relatively short length of the stop section allows the powder injector to be brought closer to the processing location, which has a positive effect on the precision of laser deposition welding.

[0020] In one embodiment, the powder injector is made of a non-magnetic hard metal, particularly in one piece. This enables efficient conveying of the powdered filler material due to the absence of magnetic effects. Furthermore, it simplifies the production of the powder injectors themselves.

[0021] Furthermore, a jet nozzle for laser material deposition is proposed, which cooperates with the powder injector to develop the disclosed advantages. The jet nozzle has a light channel for guiding at least one laser beam directed at a workpiece. Laser material deposition can be a method for high-speed laser material deposition (HS-LMD) along a feed direction. 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 throughout the process. Alternatively, they can vary depending on 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 shine 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.

[0022] The blasting nozzle further has a powder unit arranged radially outside the light channel for guiding at least one powder jet in a powder conveying direction. The powder conveying direction indicates the direction along which a powdered filler material is guided. The powder jet can be applied to the workpiece with at least a first powder focus. The powder unit can be located radially outside the light channel, starting from the longitudinal direction of the blasting nozzle, and can be part of an external structure that surrounds the light channel. The powder jet can guide at least one 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 at least indirectly. The powder jet is fully or partially focused on the first powder focus.The first powder focus is the point to which the powder unit directs the powder jet. The first powder focus can be eccentric to a center point of the light channel. The jet nozzle can also direct the powder jet to multiple powder foci.

[0023] The powder unit has a plurality of injector guides, each of which can accommodate a powder injector. An injector guide can serve as a receptacle for a powder injector. The injector guides can be incorporated into the powder unit by machining. Alternatively, they are additively manufactured. The injector guides can be adapted to the respective powder injector to be used. The jet nozzle can have at least two injector guides that lie opposite one another. In particular, it can have four or more injector guides. The plurality of injector guides can be closed in the circumferential direction of the jet nozzle or arranged in the manner of a partial circle or in the manner of a partial elongated hole.

[0024] At least one, in particular each, injector guide has an inner wall contour that tapers at least partially in the powder conveying device to accommodate a positioning section of the powder injector. The powder conveying direction indicates the direction along which the powder-form filler material is guided through the powder injector. The taper can be a continuous reduction in the diameter of the inner wall contour, at least in sections. It can have a step that separates a first section, which is designed to accommodate the positioning section, from a second section, which is designed to accommodate the stop section.

[0025] The taper represents a beveled shoulder to absorb the axial forces of the powder injector, reducing the minimum distance between the powder injector outlet and the nozzle tip of the jet nozzle. The taper eliminates the need for a solid shoulder in the injector guide, allowing the powder injector to be brought closer to the processing location, increasing the precision of the powder jet and thus promoting higher-quality application of the functional layer.

[0026] In one embodiment, the inner wall contour has a stop that is inclined by less than 90° with respect to the powder feed direction in order to accommodate a stop section of the powder injector. The stop can have an angle with respect to the powder feed direction that can correlate with a cutting angle of a drill that drills the injector guide and is, for example, 70°. This enables a gap-free depth stop between the injector guide and the powder injector. Furthermore, the stop enables shielding of the powder injector from reflection of laser radiation from the machined workpiece. The interaction of the positioning section and the stop section ensures a separation of functions when inserting the powder injector into the injector guide. The depth stop is realized via the stop section, the radial positioning via the positioning section.The positioning of the powder injector in the blasting nozzle is thus precisely defined, resulting in fewer tolerances. The actual position of the powder injector in the blasting nozzle corresponds essentially to the theoretical position without any tolerances, which enables more precise and / or closer-tolerance application of the powder jet to a workpiece. Furthermore, the separation of functions ensures efficient assembly of the powder injector, preventing the powder injector from sitting loosely in the injector guide, which can result from static over-determination.

[0027] In one embodiment, the inclination of the taper corresponds, at least in sections, in particular in a first section, to a positioning bevel of the powder injector and / or the inclination of the stop corresponds, at least in sections, in particular in the case of a stop, to a stop bevel of the powder injector. The taper can lie, at least in sections, in a range between 5° and 45°, in particular between 15° and 25°. The inclination of the stop can initially lie, in sections, in particular in the first section, in a range between 45° and 85°, in particular between 60° and 80°. This further contributes to enabling efficient, robust, and cost-effective insertion of the powder injector into the injector guide and also to increasing the quality of the powder feed.

[0028] In one embodiment, at least one, in particular each, of the plurality of injector guides is drilled. In particular, remachining of the bore in the form of additional milling is not necessary, since the stop can be configured according to the cutting angle of a drill used, for example, 70°.

[0029] The disclosure further relates to a system with a jet nozzle, in particular with the features of the present disclosure, and a plurality of powder injectors for guiding at least one powder jet in a powder conveying direction, in particular with the features of the present disclosure, wherein each powder injector is inserted into an injector guide of the jet nozzle. An injector tip of a first powder injector, located at the front in the powder conveying direction, is spaced from an injector tip of an adjacent powder injector by a distance that is less than twice the wall thickness of a conveying shaft of the powder injector. Such close arrangement of two adjacent powder injectors can be made possible by the positioning section of the powder injector in interaction with the taper of the injector guide. This allows the system to be implemented in a space-saving manner with a high functional density.Furthermore, the powder focus of the powder injectors can be adjusted efficiently and with low tolerances due to the close spatial relationship to one another.

[0030] Short description of the characters

[0031] Preferred further embodiments of the invention are explained in more detail in the following description of the figures. In the figures:

[0032] Figure 1 shows a longitudinal section along a powder injector with a positioning bevel, a stop bevel and a hose bevel,

[0033] Figure 2 shows a section of a powder injector inserted into an injector guide of a jet nozzle;

[0034] Figure 3 shows a plurality of powder injectors as they can be used in a plurality of injector guides; and

[0035] Figure 4 shows a jet nozzle in whose injector guides powder injectors are inserted.

[0036] Detailed description of preferred embodiments

[0037] 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.

[0038] Figure 1 shows a powder injector 1 for use in an injector guide 101 of a jet nozzle 100 (see Figure 4). In a powder conveying direction 2, an injector tip 3 is located at the front, and a hose interface 4 is located at the rear. The injector tip 3 has a positioning section 5, in which an outer wall 6 is inclined relative to the powder conveying direction by a positioning bevel 7. The injector tip 3 further has a stop section 8 that adjoins the positioning section 5. An outer wall 9 of the stop section 8 is inclined relative to the powder conveying direction 2 by a stop bevel 10 that is different from the positioning bevel 7, wherein the stop bevel 10 is less than 90°.

[0039] Between the injector tip 3 and the hose interface 4 is a conveyor shaft 11. The conveyor shaft 11 is shaped like a hollow tube with a constant wall thickness. The conveyor shaft 11 has a substantially constant cross-section. The hose interface 4 has an inner wall 12 which is inclined by a hose bevel 13 with respect to the powder conveying direction 2. The hose bevel 12 ensures a continuous transition between an inner diameter of a feed line for the powdered filler material and an inner diameter 14 of the conveyor shaft 11. The continuous transition of the powdered filler material into the powder injector 1 minimizes friction between the powdered filler material and the powder injector 1 by preventing turbulence.

[0040] The injector tip 3 has a front ring 15. This represents the section of the powder injector 1 that is furthest forward in terms of the conveying capacity 2. A diameter of the front ring 15 exceeds the inner diameter 14 of the conveying shaft 11. In this way, the injector tip 3, in particular the stop section 8, widens the inner diameter 14 of the conveying shaft 11, which promotes the powder jet emerging from the powder injector 1 in the form of a powder cone. An outlet opening 16 of the powder injector 1 therefore has a smaller diameter than the front ring 15. The conveying shaft 11 has a wall thickness 17 that is essentially constant. A wall thickness of the injector tip 3 is less than the wall thickness 17 of the conveying shaft due to the positioning bevel 7 and the stop bevel 10.Accordingly, a wall thickness of the hose interface 4 is below the wall thickness 17 of the conveyor shaft due to the inclined inner wall 12 of the hose interface 4.

[0041] Figure 2 shows the powder injector 1 inserted into a blasting nozzle 100. The blasting nozzle 100 has a plurality (not shown) of injector guides 101, into each of which a powder injector 1 is inserted. The blasting nozzle 100 further has a light channel 102 for guiding at least one laser beam directed onto a workpiece (see Figure 4). Arranged radially outside the light channel 102 is a powder unit 103 for guiding at least one powder jet in the powder conveying direction 2. The powder unit 103 has the plurality of injector guides 101. Each injector guide 101 has an inner wall contour 104 that tapers at least in sections in the powder conveying direction 2 in order to accommodate the positioning section 5 of the powder injector 1.

[0042] The taper can be a continuous reduction in the diameter of the inner wall contour 104, at least in sections. It can have a step 105 that separates a first section 106, which is designed to receive the positioning section 5, from a second section in the manner of a stop 107, which is designed to receive the stop section 8. The first section 106 can be inclined relative to the powder conveying direction 2 such that it correlates with the positioning bevel 7. For example, the inclination of the first section 106 can be in a range between 5° and 45°, in particular between 15° and 25°. Accordingly, the stop 107 can be inclined relative to the powder conveying direction 2 such that it correlates with the stop bevel 10. For example, the inclination of the stop 107 can be in a range between 45° and 85°, in particular between 60° and 80°.The first section 106 represents a tapered shoulder for absorbing axial forces of the powder injector 1, which reduces the minimum distance between the outlet opening 16 of the powder injector 1 and a nozzle tip of the jet nozzle 100. Thus, the tapering eliminates a solid shoulder in the injector guide 101, allowing the powder injector 1 to be brought closer to the processing location, which increases the precision of the powder jet and thus promotes a higher-quality application of the functional layer.

[0043] Figure 3 shows the plurality of powder injectors 1 arranged in a jet nozzle (not shown). The injector tip 3 has a length in the powder conveying direction 2 that is less than one-tenth of the length of the powder injector 1. The hose interface 4 has a length in the powder conveying direction that is less than one-twentieth of the length of the powder injector 1. The positioning section 5 and its interaction with the first section 106 of the jet nozzle 100 makes it possible to minimize the distance between two adjacent powder injectors 1 in the region of the injector tip 3 in a circumferential direction. The distance between two adjacent powder injectors 1 is less than twice the wall thickness 17 of the conveying shaft 11 of the powder injector.

[0044] Figure 4 shows the blasting nozzle 100, in whose injector guides 101 a powder injector 1 is inserted. Each powder injector 1 is connected to a powder supply line 108. These supply the powdered filler material to the respective powder injector 1, so that it is conveyed to the processing location at an angle relative to the axis of the light channel 102. The powder injectors 1 are connected to the powder supply lines 108 in the area of ​​the nozzle mouth 103. The blasting nozzle 100 also has a cooling channel, which is part of a cooling circuit via a supply line 109 and a discharge line 110.

[0045] Where applicable, all individual features presented in the embodiments may be combined and / or exchanged without departing from the scope of the invention.

[0046] List of reference symbols

[0047] 1 powder injector 15 forehead ring

[0048] 2 Powder conveying direction 16 Outlet opening

[0049] 3 Injector tip 20 17 Wall thickness of the production shaft 4 Hose interface

[0050] 5 Positioning section 100 jet nozzle

[0051] 6 Outer wall of the positioning section101 injector guide

[0052] 102 Light Channel

[0053] 7 Positioning chamfer

[0054] 25 103 Powder unit 8 stop section

[0055] 104 Interior wall contour

[0056] 9 Outer wall of the stop section

[0057] 105 level

[0058] 10 stop bevel

[0059] 106 first section

[0060] 11 Production shaft

[0061] 107 attack

[0062] 12 Inner wall of the hose interface

[0063] 30 108 Powder feed line 13 Hose bevel

[0064] 14 Inner diameter of the production shaft

Claims

Claims 1. A powder injector (1) for use in an injector guide (101) of a jet nozzle (100) for laser deposition welding, comprising an injector tip (3) located at the front in a powder conveying direction (2) and a hose interface (4) located at the rear in the powder conveying direction (2); wherein the injector tip (3) has a positioning section (5) in which an outer wall (6) of the powder injector (1) is inclined relative to the powder conveying direction (2) by a positioning bevel (7), and a stop section (8) adjoining the positioning section (5) in the powder conveying direction (2), in which stop section an outer wall (9) of the powder injector (1) is inclined relative to the powder conveying direction (2) by a stop bevel (10) which is different from the positioning bevel (7) and is less than 90°.

2. Powder injector (1) according to claim 1, wherein the positioning chamfer (7) lies in a range between 5° and 45°, in particular between 15° and 25°.

3. Powder injector (1) according to one of the preceding claims, wherein the stop bevel (10) lies in a range between 45° and 85°, in particular between 60° and 80°.

4. Powder injector (1) according to one of the preceding claims, wherein an inner wall (12) of the hose interface (4) is inclined relative to the powder conveying direction (2) by a hose bevel (13), which is inclined in particular in a range between 30° and 80°, further in particular between 40° and 60°.

5. Powder injector (1) according to one of the preceding claims, further comprising a conveyor shaft (11) which extends along the powder conveyor direction (2) between the injector tip (3) and the hose interface (4) in order to convey a medium, in particular a powder and / or powder mixture, through the powder injector (1), wherein the conveyor shaft (11) has a substantially constant cross-section.

6. Powder injector (1) according to one of the preceding claims, wherein the injector tip (3) has an end ring (15) closing the stop section (8) in the powder conveying direction (2), the diameter of which exceeds an inner diameter (14) of a conveying shaft (11) of the powder injector (1).

7. Powder injector (1) according to one of the preceding claims, wherein the injector tip (3) is less than one-tenth of a length of the powder injector (1) and / or wherein the hose interface (4) is less than one-twentieth of the length of the powder injector (1).

8. Powder injector (1) according to one of the preceding claims, wherein a length of the positioning section (5) in the powder conveying direction (2) exceeds a length of the stop section (8) by at least four times.

9. Powder injector (1) according to one of the preceding claims, which is made of a non-magnetic hard metal, in particular in one piece.

10. A jet nozzle (100) for laser material deposition, comprising a light channel (102) for guiding at least one laser beam directed onto a workpiece; and a powder unit (103) arranged radially outside the light channel (102) for guiding at least one powder jet in a powder conveying direction (2); wherein the powder unit (103) has a plurality of injector guides (101) into which a powder injector (1), in particular according to one of the preceding claims, can be inserted, wherein at least one, in particular each, injector guide (101) has an inner wall contour (104) which tapers at least partially in the powder conveying direction (2) in order to accommodate a positioning section (5) of the powder injector (1).

11. Jet nozzle (100) according to claim 10, wherein the inner wall contour (104) has a stop (107) which is inclined by less than 90° with respect to the powder conveying direction (2) in order to receive a stop section (8) of the powder injector (1).

12. Jet nozzle (100) according to one of claims 10 or 11, wherein the inclination of the taper corresponds at least in sections to a positioning bevel (7) of the powder injector (1) and / or wherein the inclination of the stop (107) corresponds at least in sections to a stop bevel (10) of the powder injector (1).

13. Jet nozzle (100) according to one of claims 10 to 12, wherein at least one, in particular each, of the plurality of injector guides (101) is drilled.

14. System comprising a jet nozzle (100), in particular according to one of claims 10 to 13, and a plurality of powder injectors (1) for guiding at least one powder jet into a powder conveying direction (2), in particular according to one of claims 1 to 9, wherein a powder injector (1) is inserted into an injector guide (101) of the jet nozzle (100), wherein an injector tip (3) of a first powder injector (1) located at the front in the powder conveying direction (2) has a distance from an injector tip of an adjacent powder injector that is less than twice the wall thickness (17) of a conveying shaft (11) of the powder injector (1).

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