EP4117850A1

EP4117850A1 - Device and method the production and secondary machining of layers applied by laser cladding

Info

Publication number: EP4117850A1
Application number: EP20780558.1A
Authority: EP
Inventors: Phillip Utsch; Dominik DOBRZANSKI
Original assignee: HPL Technologies GmbH
Current assignee: HPL Technologies GmbH
Priority date: 2020-03-12
Filing date: 2020-09-09
Publication date: 2023-01-18
Also published as: US20230136257A1; KR20220140032A; CN115379918A; WO2021180257A1; CA3171144A1; DE102020106823A1; MX2022011193A

Abstract

The invention relates to a device (1) for laser cladding, a method (100) for operating such a device, and a component (4') produced using such a method and/or such a device comprising a laser cladding unit (2) having at least one laser cladding head (3) disposed thereon, one or more material sources (5) for supplying the laser cladding head with a material (M) to be applied, and a laser beam source (6) for supplying the laser cladding head with laser light (L) for carrying out the laser cladding, wherein the device is designed to apply material layers (42, 43, 44) from an adjacent application weld signature (MS) to a surface (41) of a component (4) in the form of at least a first layer (42) made from a material (M) that comprises structures (42s) projecting from the surface of the first layer and having a first hardness (H1), and a second layer (43) applied thereto made from a material (M) having a second hardness (H2) that is less than the first hardness, and the application process is controlled so that the second layer at least partly covers the structures projecting from the first layer.

Description

DEVICE AND METHOD FOR MANUFACTURING AND FINISHING LAYERS APPLIED BY LASERAU FTRAGSCH WEISSEN

Field of invention

The invention relates to a device for laser deposition welding, a method for operating such a device and a component produced with such a device and / or such a method.

Background of the invention

Laser deposition welding is a process for surface treatment (e.g. coating, repair) and for the additive manufacturing of components with wire or powdered filler materials. Due to the greater robustness with regard to adjustment errors in the process equipment and the greater flexibility in the selection of materials, powdered filler materials are predominantly used. The powder is introduced into a melt pool generated by a laser beam on a surface of a component at a defined angle by means of a powder nozzle. When the laser radiation and powder particles interact above the melt pool, part of the laser radiation is absorbed by the powder. The unabsorbed portion is (multiple) reflected or transmitted. The part of the radiation absorbed by the powder particles leads to the powder particles being heated, while the part of the radiation that is transmitted creates the weld pool. Depending on the degree of heating of the particles in the jet-substance interaction zone, the particles of the filler material are solid and / or partially or completely liquid before entering the weld pool.

If the component is now moved in relation to the laser and the powder feed, the material of the melt pool moves out of the area of influence of the laser radiation and solidifies to form a layer. The prerequisite for producing defect-free, melt-metallurgically bonded layers is to provide process heat that is sufficient to initiate a temperature-time cycle that ensures both the substrate and the filler material melt. Depending on the laser power and the setting of further process parameters (e.g. feed speed, track spacing, Beam diameter, material supply, etc.) there is therefore a more or less pronounced mixing of filler material and component material. The powder can be injected laterally or coaxially into the weld pool.

With the usual procedure, feed rates, d. H. Relative speeds of the component compared to the laser beam, typically between 0.2 m / min and 2 m / min. In the method disclosed in DE 102011 100456 B4, the material supplied is melted above the surface by means of a correspondingly focused laser beam with high power, so that it already reaches the melt pool on the surface of the component in the melted state, which enables the component to be processed more quickly further increased feed speeds in the range> 150 m / min. With the method according to DE 102011 100456 B4, the area rate is now higher (thus the coating duration is shorter) than with the conventional method, despite the greater area rate, DE 10 2011 100 456 B4 does not provide any approaches to increasing the application rate (amount of powder applied per unit of time) .

Depending on the spatial extent of the weld pool, the materials are applied in wider or less wide build-up weld tracks with a thickness that varies over the width of the build-up weld track. The cross-section of such a build-up weld line perpendicular to the feed direction in which the laser beam moves over the component is generally dome-shaped with a maximum layer thickness in the middle of the build-up weld line and a thickness that decreases towards zero towards the edges of the build-up weld line. When material is applied over a large area by means of laser cladding, the cladding tracks are applied next to one another, and these can at least partially overlap. The resulting layer thickness of the material applied as a layer varies over the individual build-up weld traces. In addition, the molten bath movement and adhering, only partially melted powder particles generally result in a high surface roughness (compared to conventional manufacturing processes, e.g. turning, milling, grinding). If an even layer of applied material is desired as the end product, the applied layer must be reworked.

This post-processing is time-consuming. Depending on the waviness and roughness of the layer, a lot of applied material may have to be removed again for smoothing. Especially with hard layers or hard grains in composite layers, the conventional smoothing causes a time-consuming post-processing step, which, if necessary, can mechanically wear the smoothing agent heavily and thus increase the tool costs.

Particularly in the case of layer systems that contain hard material particles, the cost share of the worn smoothing agents can make up a considerable part of the value chain. It would therefore be desirable if the reworking effort could be made simple, reliable and less wear-intensive.

Summary of the invention

It is therefore an object of the invention to provide an effective laser deposition welding process that enables simple, reliable and less wear-intensive post-processing.

This object is achieved by a device for laser deposition welding with a laser deposition welding unit with at least one laser deposition welding head arranged thereon, one or more material sources for supplying the laser deposition welding head with a material to be deposited and a laser beam source for supplying the laser deposition welding head with laser light for performing the laser deposition welding, the device being designed for this purpose is, the application of material layers from adjacent build-up weld tracks on a surface of a component in the form of at least one first layer made of a material comprising structures protruding from the surface of the first layer with a first hardness and a second layer applied thereon made of a material with a second hardness less than the first hardness, wherein the application process is controlled so that the second layer at least the structures protruding from the first layer partially covered.

The following should be explained in terms of the terms:

First of all, it should be expressly pointed out that in the context of the present patent application, indefinite articles and numerical information such as "one", "two" etc. should generally be understood as "at least" information, i.e. as "at least one ...", "At least two ..." etc., unless the context expressly results or it is for the It is obvious or technically imperative for a person skilled in the art that only "exactly one ...", "exactly two ..." etc. can be meant.

The term "laser cladding" refers to all processes in which a material passing through a laser cladding head in the direction of the component to be processed, for example a powdery material, is carried out by means of a laser beam, which is also guided through the material by the laser cladding head in the direction of the component to be processed, is melted in a melt pool generated by the laser beam on the surface of the component and is thus applied to the surface of the component, which is also melted by the laser beam. The subsequently solidified material remains there as a material welded to the surface in the form of a build-up weld trace. If the build-up weld tracks are applied next to one another or even at least partially overlapping, the component can be exposed to the surface with material in the form of a layer of this material. The laser cladding head comprises, for example, optics for the laser beam and a powder feed nozzle including an adjustment unit for the material to be applied, possibly with an integrated, local protective gas supply. In this case, the laser beam can also be guided in such a way that the material is already melted in the laser beam, for example by a laser beam that has a focal point above the surface of the component.

The term “laser cladding unit” refers to a component that includes the laser cladding head (s). The laser cladding head (s) can be attached to a support plate of the laser cladding unit, for example. The fastening can preferably be carried out in such a way that if there are several laser welding heads, the laser deposition welding heads can move relative to one another. In addition, the laser deposition welding unit as a whole can be arranged in the device in a spatially movable manner, for example on an adjustment unit of the device. As an embodiment, the laser cladding unit can be arranged on a robot arm which can move the laser cladding unit as desired spatially by means of suitable travel curves. The number of laser deposition welding heads is at least one here. Two, three, four, five or more laser deposition welding heads can therefore also be included in the laser deposition welding unit. How many laser cladding welding heads can be present in the device is in the Usually a geometric problem and is determined by the size of the laser deposition welding heads and the component to be processed.

The term “laser deposition welding head” refers to the unit which, by means of the laser beam passed through it, creates a laser weld point on the surface of the component to be processed, and which melts the material also passing through it in the laser beam on the way to the surface of the component, so that it melts when it hits the surface of the component is welded to it. The term “laser welding point” describes the spatial location on the surface of the component where the melted material is applied to the surface by means of laser deposition welding. The laser welding point can also be referred to as the melting area of the applied material, in which the material melted by means of laser light hits the surface of the component.

The applied material can, for example, be provided in powder form for laser deposition welding. Any material suitable for laser deposition welding can be used as the material. For example, the material can comprise or consist of metals and / or metal-ceramic composites (so-called MMCs). A person skilled in the art can select the materials that are suitable for the respective laser deposition welding process. The material can be fed to the laser heads from a single conveyor unit. The device can, however, also comprise several conveying units, whereby the laser cladding heads can be supplied with different materials, so that the cladding tracks generated by different laser cladding heads can comprise the same or different materials or the material supply to one or more laser cladding heads during the laser cladding can be from one conveying unit to one changed or switched over to another conveyor unit with a different material. Material layers are produced from material traces applied next to one another at least partially overlapping. How many juxtaposed material tracks are required to provide a surface of the component with a material layer depends, among other things, on the material width of the respective material track. The material width is determined by the details of the design of the laser deposition welding heads, such as, for example, material beam width, laser energy, expansion of the laser focus and / or process speed. The laser radiation is provided by means of one or more laser beam sources. The person skilled in the art can select suitable laser beam sources for laser deposition welding.

The term “on the surface of the component” refers to the current surface of the component at the point in time when the respective laser welding point passes over the surface. The surface of the component does not need to be the original surface of the component before the start of the laser deposition welding. The surface of the component can also represent the surface of an already applied build-up weld trace or a layer of applied material, since this is welded to the previous surface after application and thus itself represents the surface of the component for subsequent build-up weld traces.

The texture of the surface that deviates from an ideal flat surface is referred to here as the “protruding structures”. The texture can be determined numerically in the form of a surface roughness. Some of these structures can be located within the first layer and only part of their structure protrudes from the first layer, the present invention only considering that part of the structures which actually protrudes from the first layer. The part of the structures that is already covered by the first layer is not relevant for post-processing the applied layers. Such protruding structures can arise, for example, when applying composite materials through a second material contained therein. In one embodiment, the first layer comprises a composite material comprising a matrix material with a third hardness less than the first hardness, the first layer preferably consists of the composite material and the structures are at least partially embedded in the matrix material. Here, the composite material can be a metal-ceramic composite material that contains grains that form the structures. For example, such grains are carbite grains. Such materials are particularly characterized by their high abrasion resistance and can be used, for example, as brake linings. Here, for example, needles made of a carbide, nitride, oxide or similar material are formed on the surface of such a layer produced with laser deposition welding, the height of which can be up to half the layer applied, while the diameter of the needle is significantly smaller than that Height is.

In one embodiment, the material of the second layer is a metal or a metal alloy. Layers of metal can be reworked easily and in a defined manner. In a In a preferred embodiment, the material of the second layer is the matrix material of the first layer. This makes it possible to produce a good material bond between the first and second layer, since the first layer differs from the second layer only in the presence of the structures protruding from the first layer.

As a result of the at least partial covering of these protruding structures, the surface roughness is reduced compared to components with only one applied first layer with such structures. The structures each have a highest point and, in a valley between adjacent structures, the adjacent structures each have a lowest point assigned to them, with a distance between the highest and lowest point of the respective structure representing its height and the second layer that protruding from the first layer Structures at least up to 20%, preferably at least 40%, more preferably at least 60%, particularly preferably at least 80%, of the average height of all structures is covered. In one embodiment, the second layer completely covers the structures protruding from the first layer. Because the second layer consists of a material whose hardness is lower than that of the protruding structures, reworking of the component is facilitated or, if the structures that effectively protrude from the second layer are only small, unnecessary, since in this case the resulting Surface roughness may already meet the requirements for the coated component as the product. When the structures protruding from the first layer are completely covered, the surface roughness of the coated component corresponds to that of the surface of the second layer. Due to the fact that the second layer has a low hardness, the area of the second layer that protrudes over the structures can easily be removed by post-processing so that the structures do not determine the surface roughness of the coated component, but the strength of the overall layer composed of the first and affect the second layer significantly. Components with a completely covering second layer can be used, for example, as or in drill heads to improve the external wear protection. Components with a second layer that does not completely cover can be used, for example, as brake disks, since the friction provided by the structures and the second layer is sufficient. The terms “first layer” and “second layer” are not intended to mean that there are no additional layers between the “first layer” and the surface of the component can. For example, a “third layer” or further layers could be arranged between the first layer and the component.

The device can furthermore comprise a control unit for controlling the laser cladding process and, if necessary, the post-processing, which can be any suitable control unit, for example a processor or a computer unit on which a corresponding control program is installed and is carried out during the laser cladding and / or post-processing.

The device according to the invention enables an effective laser deposition welding process to be carried out, which enables a simple, reliable and less wear-intensive reworking effort.

In a further embodiment, the device further comprises a material removal unit which is provided to at least partially remove the structures of the first layer protruding from the second layer if the first layer is not completely covered, or if the structures of the first layer are completely covered by the second Then partially remove the second layer.

The term "material removal unit" denotes any form of removal unit with which material from a layer can be removed from this layer without completely detaching the layer from the layers below. The material removal process can be carried out mechanically, thermally, chemically or in some other way. In one embodiment, the material removal unit is a grinding unit, a milling unit or a laser melting or laser ablation unit. The material removal unit can be arranged separately from the laser deposition welding unit or connected to it or integrated therein.

In a further embodiment, the material removal unit is arranged on the laser deposition welding unit behind the laser deposition welding head, viewed in the feed direction of the laser deposition welding head. This means that the material removal process can be carried out in the same work step as the laser deposition welding process. If necessary, the residual heat of the laser deposition welding process can be used.

In a further embodiment, the protruding from the second layer Structures of the first layer are at least partially removed in that they are evaporated or melted by the material removal unit. The material removal unit can be designed as an optical unit that can direct a laser beam onto the surface of the second layer so that the structures of the first layer that still protrude from the second layer are thermally smoothed. For this purpose, it can comprise lenses, mirrors, light guides or other optical components that can optionally be cooled or exposed to inert gas. This thermal smoothing takes place, for example, by melting and subsequent melting to a smoother surface or by evaporation of the structures. In this case, the material removal unit smooths the surface in that the smoothing process converts at least some of the structures in such a way that they disappear through the smoothing process or are at least reduced in size in the direction of a more ideal surface. The smoothing by the material removal unit thus reduces the surface roughness of the aftertreated surface of the second layer. The structures which have the largest share of the surface texture or surface roughness of the surface of the second layer to be reworked are thermally affected by the laser beam. During post-processing, evaporation can always be carried out particularly effectively and precisely when the structures to be evaporated are narrow and high, so that the thermal conductivity of the structures is significantly lower than the layer of the applied material as an extended body. In this case, the respective structure can be partially or completely evaporated. This is particularly the case with metal-ceramic composite materials with grains in the form of needles made of carbide, nitride, oxide or similar material, in which the diameter of the needle is significantly smaller than the height at which it emerges from the second Stick out layer. Since the second layer already at least partially covers the structures, the part of the structures to be evaporated or melted is smaller than the height of the structures with which they protrude from the first layer. Due to the thin shape of the structures, the energy injected by the laser beam cannot flow away quickly enough via the structure into the second layer, so that the remaining needles are heated up and evaporate without the applied second layer becoming too strong heat. A laser beam guided accordingly over the surface evaporates the structures that are still protruding and thus significantly smooths the surface. The laser beam smooths the surface in a continuous process in which the structures do not are recorded separately, but depending on the length in a statistical process pass through the laser beam and thus smoothed or evaporated. The laser cladding welding head is preferably used as the material removal unit, since the optical components and the light source are already present and the parameters of the laser beam and the beam guidance only need to be adapted to the material removal purpose.

In an alternative embodiment, when the first layer is completely covered by the second layer, the material removal unit removes it over the entire area, at least until the structures are reached. For this purpose, the material removal unit can be designed, for example, as a grinding, milling or other mechanical processing unit. Such material removal units can, depending on the design, remove the second layer over a large area, so that the post-processing step can be carried out effectively and with the shortest possible post-processing time.

In a further embodiment, the material removal unit is designed to stop the removal when at least the highest or some of the highest structures protruding from the surface of the first layer is or are reached by the material removal unit as a result of the removal process. This means that the structures protruding from the first layer do not yet determine the surface roughness of the second layer and thus that of the coated component, but they still have a significant impact on the strength of the overall layer made up of the first and second layers, which significantly contributes to the durability of the overall layer package.

In a further embodiment, the material removal unit comprises a sensor which, during the removal process, detects a transition between the sole removal of the material with the second hardness and an at least partial removal of the structure with the first hardness. The sensor can use any suitable technology, for example, to differentiate between a softer material (second layer) and a harder material (said structures of the first layer), a change in the surface structure, surface roughness and / or other property differences between the first and second layer . In a preferred embodiment, the sensor is designed to recognize the changing mechanical, optical and / or acoustic properties of the material to be removed at the transition. For this purpose, the sensor can be a force sensor, a torque sensor, a speed sensor, a surface roughness sensor, an optical, be tactile, capacitive, inductive or acoustic sensor.

In a further embodiment, the device comprises several laser cladding heads for (quasi) simultaneous application of material to a surface of the component, all of which are supplied in the device with the material to be applied and with laser radiation for performing the laser cladding. The term "(quasi-) simultaneous application" describes the process of laser deposition welding, with separate deposition welding tracks per laser deposition welding head being applied to the surface simultaneously (in advance or after) with other deposition welding tracks using other laser deposition welding heads. This (quasi) simultaneous application takes place at the same time, but at different positions on the component, i.e. at different locations on the component. This means that the material applied to the surface per unit of time increases proportionally with the number of laser cladding heads. The separate build-up welding tracks can adjoin one another or, if necessary, at least partially overlap. If necessary, the separate build-up welding tracks can also be applied directly to one another. The (quasi) simultaneous application of material by means of several laser cladding heads enables an even more effective laser cladding process with a higher application rate for a wide variety of materials and a shorter process time for the component than would only be possible with a laser welding head. In order to achieve a shorter process time, the feed rate does not need to be increased compared to known methods, which improves the quality of the applied layer and helps to avoid layer defects such as cracking by means of a process-appropriate feed rate. For example, when machining brake disks by means of laser deposition welding, the machining times that have been customary up to now can be reduced from 3-15 minutes to less than 1 minute. In a further embodiment, each laser cladding welding head applies the cladding weld trace generated by it, at least partially overlapping with the adjacent cladding weld traces generated by the other laser welding heads, so that the material is applied flatly on the surface.

In a further embodiment, the laser weld points generate build-up weld tracks with a material width along the feed direction on the surface in which a first offset of adjacent laser weld spots is between 10% and 90%, preferably between 40% and 60%, particularly preferably 50%, of the material width of the build-up weld track . The term “adjacent laser weld points” refers to two laser weld points that produce build-up weld traces of material applied to the surface of the component, which adjoin one another and, if necessary, can at least partially overlap to produce a two-dimensional application of the material. Adjacent laser welding points can be generated by neighboring laser welding heads. Here, adjacent laser welding points and / or laser welding heads do not necessarily designate laser welding points or laser welding heads that have the smallest geometrical distance from one another, but are or generate those laser welding points that create adjacent build-up weld tracks. The preheating of the component can be controlled in a targeted manner by the at least first offset of the adjacent laser welding points with respect to one another, which simplifies the processing of difficult-to-weld alloys or, depending on the alloy, makes it possible in the first place. The post-processing effort is also reduced by the at least first offset of a suitable size.

In a further embodiment, the adjacent laser weld points on the surface of the component have a second offset to one another in the feed direction. With this second offset of the laser welding points, the preheating of the component can also be controlled in a targeted manner, in particular in conjunction with the first offset, which further simplifies the processing of difficult-to-weld alloys or, depending on the alloy, makes it possible in the first place. The second offset with a suitable size, in particular in conjunction with the first offset, also further reduces the post-processing effort. Here, the laser welding head with the second offset to the adjacent build-up weld track can be used to remelt the adjacent build-up weld track in addition to applying its own build-up weld track.

In a further embodiment, the device is designed to apply at least one third layer between the component and the first layer.

The invention further relates to a method for operating a device according to the invention for laser deposition welding with a laser deposition welding unit with at least one laser deposition welding head arranged thereon for the application of material in the form of one or more adjacent deposition welding tracks on a surface of a component to produce material layers resulting therefrom, one or more material sources for supplying the laser cladding welding head with the material to be applied and a laser beam source for supplying the laser cladding welding head with laser light for performing the laser cladding and a material removal unit for processing the applied material, comprising the following steps:

Applying at least one first layer of a material which comprises structures protruding from the surface of the first layer and having a first hardness;

Application of a second layer made of a material with a second hardness less than the first hardness, a layer thickness of the second layer being such that the second layer at least partially covers the structures protruding from the first layer.

With the method according to the invention, a laser deposition welding process is effectively carried out, which enables a simple, reliable and less wear-intensive post-processing effort.

In one embodiment of the method, the structures each having a highest point and, in a valley between adjacent structures, the adjacent structures each having a lowest point assigned to them, with a distance between the highest and lowest point of the respective structure representing the height thereof of the second layer until the second layer covers the structures protruding from the first layer by at least 20%, preferably at least 30%, more preferably at least 40%, particularly preferably at least 50%, of the average height of all structures also completely cover structures protruding from the first layer. In the latter case, the layer thickness of the second layer can be greater than the height of the highest structure protruding from the first layer.

In a further embodiment, the method comprises the further step:

At least partial removal of the structures of the first layer protruding from the second layer by a material removal unit in the event that the structures are not completely covered by the second layer, or partial removal of the second layer by means of the material removal unit when the structures of the first layer are completely covered by the second layer . In a further embodiment of the method, the structures are removed by the material removal unit evaporating or melting the structures; the laser cladding welding head is preferably used as the material removal unit for this purpose, or the second layer is removed by the material removal unit covering the second layer over the entire area at least up to Reaching the structures erodes.

In a further embodiment, the method comprises the further step:

Stopping the removal of the second layer when at least the highest or some of the highest structures protruding from the surface of the first layer have been reached by the material removal unit as a result of the removal process.

In a further embodiment, the method comprises the further step of recognizing a transition in the removal process between the sole removal of the material with the second hardness to an at least partial removal of the structures with the first hardness by means of a sensor of the material removal unit. In a further embodiment, the sensor detects the changing mechanical, optical and / or acoustic properties of the material to be removed at the transition.

In a further embodiment, the method comprises, before the application of the first layer, the further step of applying a third layer or further layers to the component, to which the first layer is then applied.

In a further embodiment of the method, the material removal unit moves analogously to the laser welding head over the surface of the component.

In a further embodiment, the method comprises using a plurality of laser welding heads in the device for application of the material, all laser welding heads in the device being supplied with the material to be applied and with laser radiation for performing the laser deposition welding.

The invention further relates to a component having a surface to which a first layer made of a material comprising structures protruding from the surface of the first layer and having a first hardness is applied by means of a device according to the invention or a method according to the invention, and wherein the first layer a second layer is applied from a material with a second hardness less than the first hardness, wherein the second layer at least partially covers the structures protruding from the first layer and a surface of the second layer or the structures were designed after the application of the first and second layers so that the structures no longer protrude from the second layer. The material of the second layer can be a metal or a metal alloy. Here, the first layer can comprise a composite material with a matrix material with a third hardness less than the first hardness; the first layer preferably consists of the composite material where the structures are embedded in the matrix material. In this case, the composite material can be a metal-ceramic composite material that contains grains that form the structures, preferably the grains are carbide grains. Here, the material of the second layer can be the matrix material of the first layer. Here, a third layer can be applied to the surface, to which the first layer is applied.

The embodiments listed above can be used individually or in any combination, deviating from the references to one another in the claims, to design the devices or methods according to the invention.

Brief description of the images

These and other aspects of the invention are shown in detail in the figures as follows.

Fig.l: an embodiment of the inventive device for laser deposition welding;

2: the component in a side view (a) with the first layer and the structures protruding therefrom and (b) after these structures have been partially covered by the second layer;

3: a further embodiment of the device according to the invention for

Laser deposition welding with a material removal unit for removing the structures also protruding from the second layer;

4: a further embodiment of the device according to the invention for

Laser deposition welding with a material removal unit for removing the die protruding structures completely covering the second layer;

5: a further embodiment of the device according to the invention for laser deposition welding with a material removal unit using several laser deposition welding heads for (quasi-) simultaneous application of the material to components with a planar surface;

6: a further embodiment of the device according to the invention for laser deposition welding with a material removal unit using several laser deposition welding heads for (quasi-) simultaneous application of the material to components with a cylindrical surface; and

7: an embodiment of the method according to the invention for operating the device according to the invention.

Detailed description of the exemplary embodiments

Fig.l shows an embodiment of the device 1 according to the invention for laser cladding with a laser cladding unit 2 with at least one laser cladding head 3 arranged thereon, one or more material sources 5 for supplying the laser cladding head 3 with a material M to be applied and a laser beam source 6 for supplying the laser cladding head 3 with laser light L for performing the laser cladding, the device being designed to apply layers of material 42, 43, 44 from adjacent cladding track MS to a surface 41 of a component 4 in the form of at least one first layer 42 made of a material M that comes from the surface the first layer 42 comprises protruding structures 42s with a first hardness Hl and a second layer 42 applied thereon made of a material M with a second hardness H2 less than the first hardness Hl, the application process being controlled such that d The second layer 43 at least partially covers the structures 42s protruding from the first layer 42. Here, the material of the second layer 43 can be a metal or a metal alloy. In this case, the first layer 42 can comprise a composite material VM comprising a matrix material MM with a third hardness H3 less than the first hardness H1. The first layer 42 preferably consists of the composite material VM and the structures 42s are at least partially embedded in the matrix material MM. The composite material VM can be a metal-ceramic composite material that contains grains that form the structures 42s, preferably the grains are carbide grains. The material of the second layer 43 can also be the matrix material MM of the first layer 42.

2 shows the component 4 in a side view (a) with the first layer 42 and the structures 42s protruding therefrom and (b) after these structures 42s have been partially covered by the second layer 43. The structures 42s each have a highest point PI and im Valley between adjacent structures 42s, the structures 42s adjoining the valley there each have a lowest point P2 assigned to them, with a distance between the highest and lowest point PI, P2 of the respective structure 42s representing its height Hs and the second layer 43 that from the first layer 42 protruding structures 42s at least up to 20%, preferably at least 30%, more preferably at least 40%, particularly preferably at least 50%, of the average height Hs of all structures 42s. In this case, the structures 42s generally all have different heights Hs, the overlap relating to an average height. Individual structures 42s can thus exist which, with an average coverage of, for example, 50%, still protrude more than 50% from the second layer 43. For this, other structures 42s are covered by the second layer 43 by more than 50%, so that an average degree of coverage of, for example, 50% results. However, the second layer 43 can also completely cover the structures 42s protruding from the first layer 42. In the case of carbide grains in a metal-ceramic composite material, these grains can reach heights Hs of approximately 100 pm.

3 shows a further embodiment of the device 1 according to the invention for laser deposition welding with a material removal unit 7 for removing the structures 42s also protruding from the second layer 43, which is provided to remove those protruding from the second layer 43 if the first layer 42 is not completely covered To at least partially remove structures 42s of the first layer 42. Here, the material removal unit 7 is, for example, a laser melting or laser ablation unit, the material removal unit 7 being arranged on the laser cladding unit 2 behind the laser cladding welding head 3 in the feed direction VR of the laser cladding head 3. As a result, the structures 42s of the first layer 42 protruding from the second layer 43 are vaporized or melted by the material removal unit 7 and are thus removed to such an extent that they no longer protrude from the second layer 43. In the example shown here, the needles 42s remain only stumps remain in the second layer 43, so that the surface of the second layer 43 has a low surface roughness after the post-processing by the material removal unit 7. In a preferred embodiment, the laser deposition welding head 3 is used as the material removal unit 7.

4 shows a further embodiment of the device 1 according to the invention for laser deposition welding with a material removal unit 7 for removing the second layer 43, which completely covers the protruding structures 42s, the second layer 43 being only partially removed until the structures 42s are reached, but over the entire surface . The material removal unit 7 can be a grinding unit or a milling unit. The material removal unit is designed to stop the removal when at least the highest or some of the highest structures 42s protruding from the surface of the first layer 42 are reached by the material removal unit 7 as a result of the removal process. For this purpose, the material removal unit 7 comprises a sensor 71 which, during the removal process, detects a transition U between the sole removal of the material with the second hardness H2 to an at least partial removal of the structures 42s with the first hardness Hl, for which it detects the mechanical, optical changes at the transition U and / or recognizes acoustic properties of the material to be removed. The sensor 71 can be, for example, a force sensor, a torque sensor, a speed sensor, a surface roughness sensor, an optical sensor or an acoustic sensor. Furthermore, it is shown here that at least one third layer 44 is applied between the component 4 and the first layer 42, where the device 1 is also designed to be applied. This third layer 44 can also be present in all other exemplary embodiments.

5 shows a further embodiment of the device 1 according to the invention for laser cladding with material removal unit 7 using several laser cladding heads 3 for (quasi-) simultaneous application of the material M to components 4 with a planar surface 41 Material M and with laser radiation L for performing the laser deposition welding. The laser weld points 31 generate build-up weld tracks MS with a material width along the feed direction VR on the surface 41, in which a first offset RI of adjacent laser weld points 31 between 10% and 90%, is preferably between 40% and 60%, particularly preferably 50%, of the material width of the build-up weld trace MS. Furthermore, the adjacent laser welding points 31 on the surface 41 of the component 4 have a second offset R2 to one another in the feed direction VR. In this case, the component 4 here in the form of a brake disk comprises a circular surface 41 with an axis of rotation D perpendicular to the surface 41 on which the material is applied. The brake disc 4 could be mounted on a turntable by means of the screw holes (four points around the center), via which the brake disc 4 is rotated about the axis of rotation D. For the application 110, 120, 170 of the material M, the circular surface 41 is rotated around the axis of rotation D under the laser cladding welding heads 3, so that their laser welding point 31 on the circular surface 41 with the laser cladding welding head 3 at rest would circle over the surface 41, and the laser cladding welding heads 3 are moved simultaneously in the direction of the axis of rotation D, so that the material M is applied in terms of area to the circular surface 41 in a spiral-shaped build-up welding track MS. In this case, the material removal unit 7 extends over the entire radius of the surface 41 and, if necessary, moves subsequently over the surface 41 analogously to the laser welding points 31.Alternatively, at least one of the multiple laser cladding welding heads 3 can also be designed to be operated as a material removal unit 7.

6 shows a further embodiment of the device 1 according to the invention for laser deposition welding with material removal unit 7 using several laser deposition welding heads 3 for (quasi) simultaneous application of the material M to components 4 with a cylindrical surface 41 in the example as a shaft for rotationally symmetrical components 4 with dynamic behavior the laser welding points 31 during the laser deposition welding of a device 1 according to the invention in this embodiment with three laser welding heads 3 and a material removal unit 7. The three laser welding heads 3 (here indicated as laser welding points 31) apply (quasi) simultaneously material M to the surface 41 of the component 4, wherein the laser cladding welding heads 3 each generate a laser welding point 31 on the surface 41 of the component 4 and adjacent laser welding points a first offset RI to one another perpendicular to a feed direction VR of the laser welding points 31 on the surface 41 of the Ba own uteils 4. Here, each laser cladding welding head 3 carries the cladding weld trace MS generated by it, at least partially overlapping with the adjacent cladding weld traces MS generated by the other laser welding heads 3, so that the material M is applied flatly on the surface 41. In addition, the adjacent laser welding points 31 on the surface 41 of the component 4 have a second offset R2 to each other in the feed direction VR, on the one hand to be able to control the heat transfer to adjacent build-up weld tracks MS and, on the other hand, to avoid having to arrange the laser build-up welding heads 3 too close to one another for geometric reasons . Here, the shaft 4 comprises a rotationally symmetrical surface 41 with an axis of rotation D parallel to the surface 41 on which the material is applied. For application 110, 120, 170, the rotationally symmetrical surface 41, preferably the cylindrical surface of the shaft 4, is rotated about the axis of rotation RB under the three laser cladding heads 3, so that their laser welding point 31 on the rotationally symmetrical surface 41, when the laser cladding head 3 is stationary, cross the surface 41 in a circle would; and the laser cladding welding heads 3 are moved in the feed direction VR parallel to the axis of rotation RB, so that the material M is applied in terms of area to the rotationally symmetrical surface 41 in a spiral-shaped cladding welding track MS. Here, the material removal unit 7 extends over the entire radius of the surface 41 and, if necessary, moves analogously to the laser weld points 31 subsequently over the surface 41 %, particularly preferably 50%, of the material width MB of the build-up weld track MS. The second offset R2 is set such that the temperature profiles induced by the laser weld points 31 on the surface 41 overlap to such an extent that the material M still has a residual heat that is useful / beneficial for the process in an overlapping area of adjacent build-up weld tracks MS. Alternatively, at least one of the multiple laser deposition welding heads 3 can also be designed to be operated as a material removal unit 7.

7 shows an embodiment of the method according to the invention for operating the device according to the invention for laser cladding according to one of the preceding claims with a laser cladding unit 2 with at least one laser cladding head 3 arranged thereon for applying material M in the form of one or more adjacent cladding tracks MS on a surface 41 of a Component 4 for producing material layers 42, 43, 44 resulting therefrom, one or more material sources 5 for supplying the laser deposition welding head 3 with the material M to be applied and a Laser beam source 6 for supplying the laser deposition welding head 3 with laser light L for performing the laser deposition welding and a material removal unit 7 for processing the applied material, comprising the following steps of applying 110 at least one first layer 42 made of a material, the structures protruding from the surface 41 of the first layer 42 42s with a first hardness Hl; of applying 120 a second layer 43 made of a material with a second hardness H2 less than the first hardness Hl, a layer thickness D43 of the second layer 43 being dimensioned such that the second layer 43 at least partially covers the structures 42s protruding from the first layer 42 ; the at least partial removal 130 of the structures 42s of the first layer 42 protruding from the second layer 43 by a material removal unit 7 in the event that the structures 42s are not completely covered by the second layer 43, or the partial removal 140 of the second layer 43 by means of the material removal unit 7 when the structures 42s of the first layer 42 are completely covered by the second layer 43. The ablation 130 of the structures 42s can be carried out by the material ablation unit 7 evaporating or melting the structures 42s; the laser cladding head 3 is preferably used as the material ablation unit 7 for this. Alternatively, if the structures 42s are completely covered, the removal 140 of the second layer 43 is carried out by the material removal unit 7 removing the second layer 43 over the entire area at least until the structures 42s are reached, the removal 140 of the second layer 43 being stopped 150 if at least the highest or some of the highest structures 42s protruding from the surface of the first layer 42 are reached by the material removal unit 7 as a result of the removal process 130. For this, the method comprises the further step of recognizing 160 a transition U in the removal process 140 between the sole removal of the material with the second hardness H2 to an at least partial removal of the structures 42s with the first hardness Hl by means of a sensor 71 of the material removal unit 7 not yet reached ("N"), the removal process is continued. If, on the other hand, the transition is reached ("Y"), the removal process is stopped. For this purpose, the sensor 71 can detect the changing mechanical, optical and / or acoustic properties of the material to be removed at the transition U. In some embodiments, before applying 110 the first layer 42, the method comprises the further step of applying 170 a third layer 44 or further layers to the component 4, to which the first layer 42 is then applied. It is also advantageous for an effective manufacturing process if the material removal unit 7 moves analogously to the laser welding head 3 over the surface 41 of the component 4. The time of the laser deposition welding process can be shortened by using several laser welding heads 3 in the device 1 for (quasi) simultaneous material application, all laser welding heads 3 in the device 1 being supplied with the material M to be applied and with laser radiation L for performing the laser deposition welding. The product produced with the method according to the invention is a component 4 ′ with a surface 41 to which a first layer 42 made of a material M, which comprises structures 42s protruding from the surface of the first layer 42 and having a first hardness Hl, is applied, and A second layer 43 made of a material M with a second hardness H2 less than the first hardness Hl is applied to the first layer 42, the second layer 43 at least partially covering the structures 42s protruding from the first layer 42 and a surface of the second layer 43 or the structures 42s were designed after the application of the first and second layers 42, 43 in such a way that the structures 42s no longer protrude from the second layer 43. For further details of the first, second and, if applicable, third layer, see the description for FIG.

It goes without saying that the exemplary embodiment explained above is only a first embodiment of the present invention. In this respect, the configuration of the invention is not limited to this exemplary embodiment.

List of reference symbols

1 device according to the invention for laser deposition welding

2 laser deposition welding unit

3 laser deposition welding head

31 laser welding point

4 Component at the start of laser deposition welding

4 'component with applied layers

41 Surface of the component

42 first layer

42s structures protruding from the first layer

42b post-treated structures protruding from the first layer

43 second layer

44 third layer

5 Source of material

6 laser beam source

7 Material removal unit

71 Sensor of the material removal unit

100 method according to the invention for operating a device for laser deposition welding

110 applications of at least a first layer on the surface of the component

120 applications of a second layer on top of the first layer

130 At least partial removal of the structures protruding from the second layer by means of the material removal unit

140 partial removal of the second layer by means of the material removal unit

150 Stop the erosion

160 Recognition of a transition in the removal process between the sole removal of the material with the second hardness to an at least partial removal of the structure with the first hardness

170 Application of a third layer between the component and the first layer D axis of rotation of the component during laser deposition welding

D43 Layer thickness of the second layer

The first hardness of the structures protruding from the first layer

H2 second hardness of the second layer

H3 third hardness of the matrix material

Hs height of the structure

M material to be applied / applied

MM matrix material of the composite material of the first layer

MS build-up weld trace of the applied material on the surface of the component or layer of applied material L laser light

PI highest point of a structure

P2 lowest point of a structure

RI first offset of adjacent laser weld points to one another perpendicular to

Before weft direction

R2 second offset of adjacent laser welding points to one another in the feed direction

RB rotation component during laser deposition welding

U transition between the sole removal of the material with the second hardness to an at least partial removal of the structures with the first hardness VM composite material of the first layer of matrix material and structures in the matrix material

VR feed direction of the laser deposition welding head

Claims

1. A device (1) for laser deposition welding with a laser deposition welding unit (2) with at least one laser deposition welding head (3) arranged thereon, one or more material sources (5) for supplying the laser deposition welding head (3) with a material (M) to be applied and a laser beam source ( 6) for supplying the laser cladding head (3) with laser light (L) to carry out the laser cladding, the device being designed to apply layers of material (42, 43, 44) from adjacent cladding tracks (MS) onto a surface (41) of a Component (4) in the form of at least one first layer (42) made of a material (M) which comprises structures (42s) protruding from the surface of the first layer (42) with a first hardness (Hl) and a second layer applied thereon (43) made of a material (M) with a second hardness (H2) smaller than the first hardness (Hl), the application process being controlled so that the second layer (43) at least partially covers the structures (42s) protruding from the first layer (42).

2. The device (1) according to claim 1, characterized in that the material of the second layer (43) is a metal or a metal alloy.

3. The device (1) according to claim 1 or 2, characterized in that the first layer (42) comprises a composite material (VM) comprising a matrix material (MM) with a third hardness (H3) less than the first hardness (Hl), preferably the first layer (42) consists of the composite material (VM) and the structures (42s) are at least partially embedded in the matrix material (MM).

4. The device (1) according to claim 3, characterized in that the composite material (VM) is a metal-ceramic composite material containing grains that form the structures (42s), preferably the grains are carbide, nitride, or oxide grains.

5. The device (1) according to claim 3 or 4, characterized in that the material of the second layer (43) is the matrix material (MM) of the first layer (42).

6. The device (1) according to any one of the preceding claims, characterized in that the structures (42s) each have a highest point (PI) and in a valley between adjacent structures (42s) the adjacent structures (42s) each have a deepest assigned to them Point (P2), a distance between the highest and lowest point (PI, P2) of the respective structure (42s) representing its height (Hs) and the second layer (43) the structures ( 42s) covers at least up to 20%, preferably at least 30%, more preferably at least 40%, particularly preferably at least 50%, of the average height (Hs) of all structures (42s).

7. The device (1) according to one of the preceding claims, characterized in that the second layer (43) completely covers the structures (42s) protruding from the first layer (42).

8. The device (1) according to any one of the preceding claims, characterized in that the device (1) further comprises a material removal unit (7) which is provided for the purpose of not completely covering the first layer (42) from the second Layer (43) protruding structures (42s) of the first layer (42) at least partially to be removed, or if the structures (42s) of the first layer (42) are completely covered by the second layer (43), the second layer (43) is then partially removed .

9. The device (1) according to claim 8, characterized in that the material removal unit (7) is a grinding unit, a milling unit or a laser melting or laser ablation unit.

10. The device (1) according to claim 8 or 9, characterized in that the material removal unit (7) on the laser deposition welding unit (2) is arranged behind the laser deposition welding head (3) in the feed direction (VR) of the laser deposition welding head (3).

11. The device (1) according to one of claims 8 to 10, characterized in that the structures (42s) of the first layer (42) protruding from the second layer (43) are at least partially removed by pulling them (42s) through the material removal unit (7) are evaporated or melted.

12. The device (1) according to claim 11, characterized in that the laser cladding welding head (3) is used as the material removal unit (7).

13. The device (1) according to any one of claims 8 to 10, characterized in that when the first layer (42) is completely covered by the second layer (43), the material removal unit (7) covers the entire area at least until the structures ( 42s) is removed.

14. The device (1) according to claim 13, characterized in that the material removal unit (7) is designed to stop the removal when at least the highest or some of the highest from the surface of the first Layer (42) protruding structures (42s) from the material removal unit (7) are reached as a result of the removal process.

15. The device (1) according to claim 13 or 14, characterized in that the material removal unit (7) comprises a sensor (71) which, during the removal process, leads to a transition (U) between the sole removal of the material with a second hardness (H2) recognizes an at least partial removal of the structures (42s) with the first hardness (Hl).

16. The device (1) according to claim 15, characterized in that the sensor (71) is designed to recognize the changing mechanical, optical and / or acoustic properties of the material to be removed at the transition (U).

17. The device (1) according to claim 15 or 16, characterized in that the sensor (71) is a force sensor, a torque sensor, a speed sensor, a surface roughness sensor, an optical, tactile, capacitive, inductive or acoustic sensor.

18. The device (1) according to one of the preceding claims, characterized in that the device (1) has several laser cladding welding heads (3) for the (quasi) simultaneous application of material (M) onto the surface (41) of a component (4) comprises, all of which are supplied in the device (1) with the material (M) to be applied and with laser radiation (L) for performing the laser deposition welding.

19. The device (1) according to claim 18, characterized in that the laser weld points (31) deposit weld tracks (MS) with a material width generate along the feed direction (VR) on the surface (41), in which a first offset (RI) of adjacent laser welding points (31) between 10% and 90%, preferably between 40% and 60%, particularly preferably 50%, of the material width of the Build-up weld trace (MS) is.

20. The device (1) according to claim 18 or 19, characterized in that the adjacent laser welding points (31) on the surface (41) of the component (4) have a second offset (R2) to one another in the feed direction (VR).

21. The device (1) according to one of the preceding claims, characterized in that the device (1) is designed to apply at least one third layer (44) between the component (4) and the first layer (42).

22. A method (100) for operating a device (1) for laser cladding according to one of the preceding claims with a laser cladding unit (2) with at least one laser cladding head (3) arranged thereon for applying material (M) in the form of one or more adjacent ones Deposition welding traces (MS) on a surface (41) of a component (4) for the production of material layers (42, 43, 44) resulting therefrom, one or more material sources (5) for supplying the laser deposition welding head (3) with the material (M) to be applied and a laser beam source (6) for supplying the laser cladding welding head (3) with laser light (L) for performing the laser cladding and a material removal unit (7) for processing the applied material, comprising the following steps:

Applying (110) at least one first layer (42) made of a material which comprises structures (42s) protruding from the surface (41) of the first layer (42) and having a first hardness (Hl);

Application (120) of a second layer (43) made of a material with a second hardness (H2) less than the first hardness (Hl), a layer thickness (D43) of the second layer (43) being dimensioned such that the second layer (43 ) at least partially covers the structures (42s) protruding from the first layer (42).

23. The method (100) according to claim 22, wherein the structures (42s) each have a highest point (PI) and the adjacent structures (42s) each have a lowest point (P2) assigned to them in a valley between adjacent structures (42s) , whereby a distance between the highest and lowest point (PI, P2) of the respective structure (42s) represents its height (Hs), the application (120) of the second layer (43) is carried out until the second layer (43) the structures (42s) protruding from the first layer (42) covers at least up to 20%, preferably at least 40%, more preferably at least 60%, particularly preferably at least 80%, of the average height (Hs) of all structures (42s), alternatively the second Layer (43) also completely cover the structures (42s) protruding from the first layer (42).

24. The method (100) according to claim 23, comprising the further step:

At least partial removal (130) of the structures (42s) of the first layer (42) protruding from the second layer (43) by a material removal unit (7) in the event that the structures (42s) are not completely covered by the second layer (43), or partial removal (140) of the second layer (43) by means of the material removal unit (7) with complete coverage of the structures (42s) of the first layer (42) by the second layer (43).

25. The method (100) according to claim 24, wherein the removal (130) of the structures (42s) is carried out by the material removal unit (7) evaporating or melting the structures (42s); (3) is used, or the removal (140) of the second layer (43) is carried out by the material removal unit (7) removing the second layer (43) over the entire area at least until the structures (42s) are reached.

26. The method (100) according to claim 25, comprising the further step: Stopping (150) the removal (140) of the second layer (43) when at least the highest or some of the highest structures (42s) protruding from the surface of the first layer (42) by the material removal unit (7) as a result of the removal process (130 ) are reached.

27. The method (100) according to any one of claims 24 to 26, comprising the further step of recognizing (160) a transition (U) in the removal process (140) between the sole removal of the material with the second hardness (H2) to an at least partial Removal of the structures (42s) with the first hardness (Hl) by means of a sensor (71) of the material removal unit (7).

28. The method (100) according to claim 27, wherein the sensor (71) detects the changing mechanical, optical and / or acoustic properties of the material to be removed at the transition (U).

29. The method (100) according to any one of claims 22 to 28, wherein the method includes the further step of applying (170) a third layer (44) or further layers to the component before the application (110) of the first layer (42) (4), on which the first layer (42) is then applied.

30. The method (100) according to any one of claims 22 to 29, wherein the material removal unit (7) moves analogously to the laser welding head (3) over the surface (41) of the component (4).

31. The method (100) according to any one of claims 22 to 30, comprising using a plurality of laser welding heads (3) in the device (1) for applying (110, 120, 170) the material (M), wherein all laser welding heads (3 ) are supplied in the device (1) with the material (M) to be applied and with laser radiation (L) for performing the laser deposition welding.

32. A component (4 ') having a surface (41) onto which by means of a device (1) according to one of claims 1 to 21 or a method (100) according to one of claims 23 1 to 31 a first layer (42) made of a material (M) which comprises structures (42s) protruding from the surface of the first layer (42) and having a first hardness (Hl) is applied, and wherein the first layer (42 ) a second layer (43) made of a material (M) with a second hardness (H2) less than the first hardness (Hl) is applied, the second layer (43) being the structures (42s) protruding from the first layer (42) at least partially covered and a surface of the second layer (43) or the structures (42s) were designed after the application of the first and second layers (42, 43) in such a way that the structures (42s) no longer consist of the second layer (43) stick out.

33. The component (4 ') according to claim 32, characterized in that the material of the second layer (43) is a metal or a metal alloy.

34. The component (4 ') according to claim 32 or 33, characterized in that the first layer (42) comprises a composite material (VM) comprising a matrix material (MM) with a third hardness (H3) less than the first hardness (Hl), Preferably, the first layer (42) consists of composite material (VM), where the structures (42s) are embedded in the matrix material (MM).

35. The component (4 ') according to claim 34, characterized in that the composite material (VM) is a metal-ceramic composite material which contains grains that form the structures (42s), preferably the grains are carbide, nitride , or oxide grains.

36. The component (4 ') according to claim 34 or 35, characterized in that the material of the second layer (43) is the matrix material (MM) of the first layer (42).

37. The component (4 ') according to one of the preceding claims, characterized in that a third layer (44) is applied to the surface (41), to which the first layer (42) is applied.