Laser cladding welding device with coaxial applied material supply and ranging device

Abstract

An apparatus (10) for laser cladding welding, comprising: a laser processing head (16) for causing a laser beam (14) to enter; a distance measuring device (34) for measuring a distance by means of the measuring beam (36); a scanning device (50) for deflecting the measuring beam (36); a coupling device (56) for coupling the beam path of the measuring beam (36) into the beam path of the laser beam (14); a feeding device (20) for coaxially feeding the application material; a first reflector (26) and a second reflector (28), which have a common centre axis and are arranged in a common beam path of the laser beam (14) and the measuring beam (36) between the coupling device (56) and the supply device (20); the first reflector (26) reflects the laser beam (14) and the measuring beam (36) outwardly at an angle to the centre axis to the second reflector (28); the second reflector (28) reflects the laser beam (14) in the direction of the machining region.

Description

Technical Field

[0001] The present disclosure relates to a laser cladding welding device including a distance measuring device, wherein an application material is supplied coaxially with a laser beam. Background Art

[0002] Laser cladding welding is an additive manufacturing method in which an applied material is melted by means of a laser beam and connected to at least one workpiece.

[0003] WO 2018 / 178387 A1 describes an additive manufacturing device comprising a laser device, a supply device for supplying material, and an interferometer in order to measure the distance to a workpiece by means of an optical measuring beam.

[0004] US2022 / 0134440 A1 describes a laser additive manufacturing apparatus, which includes a first reflective optical device for receiving and reflecting a laser beam and a second reflective optical device for receiving the laser reflected by the first reflective optical device. The second reflective optical device aligns a portion of the received laser light to the raw material in a cylindrical configuration coaxially with the supplied wire or powder raw material. Utility Model Content

[0005] One object of the invention is to provide a device with a compact structure, which enables an optical measuring beam for distance measurement to be moved into or around a processing area independently of direction, wherein the influence of shadows, in particular on the measuring result, is reduced or eliminated. It is particularly desirable to move the optical measuring beam in front of, behind and / or in the processing area (for in-process observation).

[0006] In addition, an object of the present invention is to provide a laser cladding welding device with coaxial material supply and distance measurement for an additive manufacturing method, which enables the laser beam (especially in the focal position) to be uniformly guided to the supplied material and uniformly melted and enables distance measurement at multiple measuring positions.

[0007] One or more of these tasks are solved by a laser cladding welding device according to a preferred embodiment.Preferred embodiments are subject of alternative embodiments.

[0008] The present disclosure relates to a device for laser cladding welding, comprising: a supply device for coaxially supplying an application material; a distance measuring device for measuring a distance by means of a measuring beam; and a scanning device for deflecting the measuring beam. The supply device can be set up to output the application material coaxially with the center axis or coaxially with the laser beam at the supply position, and / or to supply the application material coaxially to the processing area from the supply position. The first reflector and the second reflector are arranged on the common center axis of the two reflectors in the common optical path of the laser beam and the measuring beam so that the laser beam and / or the measuring beam are guided around the supply device. In particular, although the application material is supplied in a coaxial manner, the laser beam and the measuring beam can be incident substantially without shadows, because the laser beam and the measuring beam are deflected around the supply position by the first reflector and the second reflector. Even if the supply itself may cause a shadow at a certain position, the shadow appears very small and can be ignored due to the positioning in the collimated working beam. The coaxially discharged application material thus represents an obstacle on the common center axis, which is avoided by the beam path through the first and second reflectors, so that the discharged application material does not shadow the laser beam or the measuring beam.

[0009] The utility model is based on the following: the laser beam is reflected by a second reflector arranged on a common center axis in the direction of the processing area in order to cause uniform melting of the application material, while the measuring beam can be moved into the processing area and / or the surroundings by a scanning device independently of direction and substantially without shadow. In this case, a compact structure of the laser processing head is achieved by the first reflector and the second reflector and by the supply device for coaxially supplying the application material. In particular, the laser beam can be uniformly guided to the supplied application material in the focal position.

[0010] According to a first aspect of the utility model, a device for laser cladding welding comprises: a laser processing head for incident laser beam; a distance measuring device for measuring distance by means of a measuring beam; a scanning device for deflecting the measuring beam; a coupling device for coupling the optical path of the measuring beam into the optical path of the laser beam; a supply device for coaxially supplying the applied material; and a first reflector and a second reflector, wherein the first reflector is set up to reflect the laser beam and the measuring beam outwardly at an angle to the center axis onto the second reflector; and the second reflector is set up to reflect the laser beam in the direction of the processing area. The first reflector and the second reflector have a common center axis and / or are arranged on a common center axis and / or are arranged in a common optical path of the laser beam and the measuring beam. In other words, the first reflector and the second reflector have a common center axis, that is, the first reflector and the second reflector are arranged in a common optical path so that the first reflector and the second reflector have a common center axis. The first reflector and the second reflector can be arranged between the coupling device and the supply device or before the supply device along the beam propagation direction of the laser beam.

[0011] Particularly advantageously, the scanning device for deflecting the measuring beam in combination with the first reflector and the second reflector makes it possible to measure the distance to the workpiece or the applied layer thickness at at least one defined measuring position, for example before, after and / or in the processing area or at the processing position, even in the case of changes in the processing direction or the feed speed of the laser processing head. Thus, in particular by means of a targeted deflection of the measuring beam by means of the scanning device, a measurement can be achieved which is defined (for example before) with respect to the processing direction and / or the processing path. In particular, the use of two-dimensional scanning interferometric measurement methods using a reflective processing head with a deflectable laser beam is made possible.

[0012] According to another aspect of the utility model, the device for laser cladding welding includes: a laser processing head for incident laser beam; a supply device for coaxially supplying application material; and a first reflector and a second reflector, which have a common center axis, wherein the first reflector is set up to reflect the laser beam outwardly at an angle to the center axis onto the second reflector, and the second reflector is set up to reflect the laser beam in the direction of the processing area. The first reflector and the second reflector are arranged on the common center axis and / or coaxially. In other words, the first reflector and the second reflector are arranged in the optical path of the laser beam so that they have a common center axis. The first reflector and the second reflector can be arranged before the supply device along the beam propagation direction of the laser beam.

[0013] The apparatus according to this aspect may include one or more of the following features:

[0014] The processing area may be referred to as an area including the processing position (i.e. the position on which the laser beam is incident) and / or the surroundings of the processing position. In particular, the processing area may be referred to as an area including the processing position, a preceding position or area (i.e. the position to be processed or its surroundings), and / or a subsequent position or area (i.e. the position that has been processed or its surroundings).

[0015] The arrangement of the first reflector and the second reflector can be designed for an approximately rotationally symmetrical deflection of the laser beam and / or of the measuring beam.

[0016] The device can be a laser metal deposition device, also referred to as an LMD device or an LMD apparatus. The device can be, in particular, a laser cladding welding device in which the applied material is supplied in a coaxial manner in the middle. The device can be, in particular, a device for laser cladding welding workpieces. The processing area can be a processing area on the workpiece. The device can be, in particular, an LMD device with coaxial material supply and rotationally symmetrical or almost rotationally symmetrical beam guidance, including a distance measuring device with a variable measuring position. The device can be set up to apply material in a plurality of layers with respective predetermined layer thicknesses along a first direction or axis (the so-called vertical direction or axis). That is, the layer thickness can be defined along a vertical direction or axis. The vertical direction or axis can be perpendicular to the workpiece surface.

[0017] The distance can be, for example, a height or a vertical distance or a layer thickness relative to a reference plane. For example, the distance can be a distance perpendicular to the (unmachined) workpiece surface. The distance measuring device can be configured to determine the height or distance from an optical path length to a measuring position or a position on the workpiece surface, in particular from an optical path length between the measuring position or the position on the workpiece surface and the distance measuring device.

[0018] The scanning device can be a 2D scanner and / or a Galvo scanner having at least one, in particular two, reflective deflection elements, such as mirrors.

[0019] The device can further comprise a control device for controlling and / or regulating the device or components of the device, in particular for actuating the scanning device and / or the supply device and / or the laser source.

[0020] The control device can be designed to deflect or move the measuring beam by means of the scanning device, for example, on a predetermined and / or freely selectable trajectory. In particular, the control device can be designed to control the scanning device as a function of the feed speed or as a function of a change in the feed speed and / or as a function of the processing position or as a function of a change in the processing position, in order to deflect or move the measuring beam. In particular, the control device can be designed to match the measuring position to the track coordinates of a predetermined processing trajectory for producing the end product. For example, the control device can control or regulate the measuring beam position and / or the measuring beam movement as a function of the feed movement of the device and / or as a function of the laser power and / or as a function of the material feed amount and / or as a function of the material feed speed.

[0021] The device may further comprise an evaluation device for evaluating the data. The evaluation device may be part of a control and evaluation device of the device, which may comprise, for example, the control device described above. The distance measuring device may comprise an evaluation unit for determining the distance from the measurement data. However, the evaluation unit may also be integrated in the evaluation device.

[0022] In laser cladding welding, a structure can be formed from the applied material. For example, the structure can be formed on a workpiece, or the structure can form the workpiece. The formation can be realized layer by layer along the machining trajectory. For example, a wall (wall-shaped structure) can be formed by repeated or repeated application along the machining contour, each staggered in the height direction of the structure.

[0023] The device can be set up or can be used for laser cladding welding along a processing trajectory. Then, the welding or application direction or processing direction each extends along the processing trajectory. The processing trajectory can also be called a processing path. The term processing direction or processing trajectory refers to the processing direction (especially welding direction) or processing trajectory of the laser beam relative to the workpiece. The processing trajectory can especially define the processing direction. The processing trajectory may include angles or curves. The processing trajectory can be defined by the geometry of the workpiece or by the geometry of the final product to be formed in the corresponding layer or plane.

[0024] The device can be set up to position the processing area relative to the workpiece. The device can include a positioning device to position the processing area relative to the workpiece. The positioning device can include, for example, a robot arm or a gantry and / or an axis system to position or move the laser processing head and / or the workpiece. The positioning device can be set up so that the laser processing head and the workpiece are positioned and / or moved and / or oriented relative to each other. The positioning device can be set up so that the device or the laser processing head is moved and / or oriented relative to the workpiece. The positioning device can be set up so that the device or the laser processing head together with the distance measuring device, the scanning device, the coupling device, the first reflector and the second reflector arranged on and / or carried by it are moved and / or oriented relative to the workpiece. The positioning device can include a robot arm or a gantry, and the laser processing head is fastened to the robot arm or the gantry. The positioning device can include an axis system for positioning the workpiece. The positioning device can be set up so that the laser beam moves along the processing trajectory.

[0025] The laser processing head can in particular comprise a housing through which the beam path of the laser beam is guided. The laser beam can also be referred to as a processing laser beam. The laser processing head can be configured to radiate a laser beam emitted by a laser beam source or the end of a laser guidance fiber. The laser processing head can be configured to radiate the laser beam onto a workpiece. The beam guidance optics can be integrated into the laser processing head.

[0026] The distance measuring device can be a time-of-flight sensor (ToF sensor). The measuring beam is an optical measuring beam. The distance measuring device can be an interferometric distance measuring device, such as an optical coherence tomography (OCT) distance measuring device. The interferometric distance measuring device can include a light source for measuring the beam, a measuring beam for superimposing the light of the reference arm, and / or a detector of the reference arm. In other words, the distance measurement can be based on optical coherence tomography. This type of distance measurement is based on the following principle: the coherence of light that has traveled the optical path length is utilized by means of an interferometer. For this purpose, the optical measuring beam is incident on the processing area or the workpiece. A portion of the optical measuring beam is incident on the reference arm of the distance measuring device. The portion of the optical measuring beam reflected by the processing area or the workpiece is superimposed with the light of the reference arm and interferes. Information about the difference in the optical path length of the measuring arm and the reference arm can be obtained by analyzing the superimposed light. Information about the distance to the workpiece or about the surface characteristics of the workpiece can be obtained. The distance to the workpiece corresponds to the height of the workpiece at the relevant measuring position, for example, about the reference plane. Therefore, information about the existing height of the workpiece or about the surface characteristics of the workpiece can be obtained by analyzing the superimposed light, for example, information about the existing height of the workpiece at the following position, at which the cladding or application material should be applied and / or at which the cladding or application material has been applied. Preferably, the distance measuring device is a frequency domain OCT distance measuring device. In such a frequency domain OCT distance measuring device, the distance can be measured based on the spectral components of the superimposed light. Therefore, the reference arm can have a constant length (optical path length). The distance measuring device can be stationary relative to the laser processing head. In other words, the scanning device can be set up so that the measuring beam is deflected relative to the laser beam.

[0027] The distance measuring device can be set up to detect distance measurement values ​​based on the part of the measuring beam in the processing area and / or reflected by the workpiece. The distance measuring device can be set up to: detect at least one distance measurement value of the distance between the laser processing head that causes the laser beam to be incident and the workpiece, in particular the distance to the measuring position on the workpiece (i.e. the distance to the workpiece at the measuring position); and / or detect at least one distance measurement value based on the part of the measuring beam in the processing area and / or reflected by the workpiece along the measuring position or the scanning pattern of the measuring beam; and / or detect surface property data of the workpiece surface, in particular along the measuring position or the scanning pattern of the measuring beam. The distance can be determined from the at least one distance measurement value. The scanning pattern can also be called a scanning pattern, a sampling pattern, a sampling path or a movement trajectory of the measuring position on the workpiece. One or more measuring positions or scanning patterns can be determined relative to the processing position and with respect to the processing direction and / or the processing trajectory.

[0028] The scanning device can be a scanner optical device or a scanning optical device. The scanning device can be set up to deflect the measuring beam onto the scanning area or in the scanning area, for example, on the workpiece. The scanning device can include at least one movable deflection member for the measuring beam, in particular at least one movable mirror (scanning mirror). The deflection member or the scanning mirror can rotate around at least one axis. The scanning device can include a movable mirror or two movable mirrors (scanning mirrors) for deflecting the measuring beam. The first movable mirror can rotate around a first rotation axis, and the second movable mirror can rotate around a second rotation axis, wherein the first rotation axis and the second rotation axis are at an angle to each other, for example, an angle between 45° and 135°, in particular an angle of about 75° or 90°. Alternatively, the scanning device can have a movable mirror that is rotatable or oscillating around at least two axes. In order to move the mirror or the first and second mirrors, the scanning device can accordingly include at least one galvanometer drive. Accordingly, the mirror or the first and second mirrors can be configured as a galvanometer mirror, referred to as a Galvo mirror. Accordingly, the scanning device can be designed as a galvanometer or a galvo scanner, in particular an XY-galvo scanning system. Alternatively, the scanning device can have a MEMS-based, piezoelectric and / or inductive drive. The scanning device can also be designed as a prism scanner or a lens scanner. The scanning mirror can also be called an sampling mirror.

[0029] The scanning device can be arranged between the distance measuring device and the assembly consisting of the first and second reflectors, in particular between the distance measuring device and the coupling device. The coupling device can be arranged after the scanning device in the optical path of the measuring beam, that is, the scanning device can be arranged between the distance measuring device and the coupling device. The scanning device can be arranged in the measuring arm in the case of an interferometric distance measuring device. The scanning device can be arranged between the light source for the measuring beam and the coupling device in the optical path of the measuring beam. The scanning device can be a 2D scanning device. The scanning device can be set up to deflect the measuring beam in a first direction and deflect the measuring beam in a second direction transverse to the first direction. The first and second directions can be orthogonal to each other. The scanning device can be set up to deflect the measuring beam from a zero position. The zero position can represent an undeflected orientation of the measuring beam, in which the measuring beam extends coaxially with the optical axis of the laser beam optical path.

[0030] The scanning device can be set up to deflect the measuring beam independently of the laser beam. The scanning device allows the measuring beam to be deflected so that it impinges on the processing area or the workpiece at the measuring position or along a scanning pattern. The scanning device can be set up in particular so that the measuring beam is deflected in the beam path of the measuring beam to the processing area before the measuring beam is coupled into the beam path of the laser beam. The measuring beam can thus be positioned relative to the processing position on the workpiece and can be freely positioned on the workpiece, in particular within the scanning area of ​​the scanning device. The scanning area can also be referred to as a deflection area or sampling area.

[0031] The scanning device can be configured to guide the light of the measuring beam output by the coupling device and reflected by the processing area or by the workpiece back to the distance measuring device. In particular, the optical path of the measuring beam through the scanning device can be equal in both directions (at each moment or at a given working position or deflection position of the scanning device), i.e. the direction of the incident measuring beam and the direction of the measuring beam returning to the distance measuring device.

[0032] The distance measuring device and the scanning device can together form a distance measuring device with a variable measuring position, in particular an OCT distance measuring device with a variable measuring position.

[0033] The distance measuring device and / or the scanning device can be configured to adjust the focal position of the measuring beam, preferably independently of the focal position of the laser beam. In particular, the distance measuring device and / or the scanning device can be configured to focus the measuring beam onto a workpiece, in particular onto a workpiece surface.

[0034] The scanning device can be set up to adjust and / or modify the propagation direction and / or propagation of the measuring beam. This adjustment of the propagation enables the measuring beam to be arranged on the first and second reflectors so that the measuring beam points to the interaction area from the correct direction and has the correct deflection with it. In particular, the scanning device can be set up to adjust and / or modify the deflection of the measuring beam with the optical axis of the scanning device, the inclination of the measuring beam with the optical axis and / or the beam diameter of the measuring beam. For this purpose, the scanning device can include the at least one mirror and, if possible, other optical elements. The scanning device can include, for example, collimating optical devices (for example, at least one collimating lens) and / or focusing optical devices for collimating the measuring beam. The deflection and / or inclination of the measuring beam with the optical axis makes it possible to observe certain positions around the focus (i.e., the position where the distance measurement should be implemented). The unique unambiguity of the measurement result of the distance measurement can be contributed to by the stronger characteristics of the beam propagation and the unique and clear correspondence of the measuring beam position and / or the measuring beam movement with the feed direction and / or feed speed (processing direction and / or processing speed). The scanning device and / or the control device for controlling the scanning device can be configured to place the measuring beam on the first and / or second reflector at a position with a respectively unique and unambiguous reflection direction. Interference peaks can thereby be prevented, which would lead to non-unique and unambiguous measurements. In particular, the scanning device and / or the control device for controlling the scanning device can be configured to exclude a center point of the first reflector (e.g., the reflector tip) as a position of the measuring beam.

[0035] The coupling device is arranged after the scanning device in the optical path of the measuring beam. That is, the coupling device is arranged after the scanning device in the optical path of the measuring beam in the direction of the processing area. In other words, the scanning device is arranged between the distance measuring device and the coupling device. Therefore, the coupling device is set up so that the measuring beam (e.g., emitted by the light source of the measuring beam) is coupled into the optical path of the laser beam in the direction of the processing area after passing through the scanning device. The coupling input of the optical path of the measuring beam into the optical path of the laser beam can include the coupling input of the measuring beam into the optical path of the laser beam in the direction of the workpiece and / or the coupling out of the light reflected by the measuring beam (by the workpiece) from the optical path of the laser beam passing in the opposite direction. The coupling device may include a beam splitter, such as a dichroic mirror. The coupling device may be referred to as a coupler or a beam coupler. The coupling device may be set up so that the optical path of the measuring beam (or its optical axis) is coupled into parallel to the optical axis of the optical path of the laser beam. Therefore, the measuring beam or its optical axis can be guided parallel to the laser beam, especially through the first reflector and / or the second reflector.

[0036] The supply device is configured to supply the application material coaxially, i.e. coaxially with the center axis (the common center axis of the first reflector and the second reflector) or coaxially with the optical path of the laser beam (before the reflectors). The supply device can be configured to supply the application material coaxially and / or centrally, i.e. centrally with respect to the center axis or the optical path of the laser beam. The supply device can be configured to output the application material coaxially with the center axis (the common center axis of the first reflector and the second reflector) or coaxially with the optical path of the laser beam at the supply position (i.e. in a direction coaxial with the center axis or the optical path of the laser beam). The supply device can be configured to supply the application material from the supply position coaxially with the center axis to the processing area. The supply device can have an output opening for the application material at the supply position.

[0037] The processing region can be located behind the first reflector and / or behind the second reflector on the center axis of the first and second reflector in the beam path of the laser beam.

[0038] The first reflector and the second reflector are arranged such that they have a common center axis. The assembly consisting of the first and second reflectors can be arranged between the coupling device and the supply device. The common beam path of the laser beam and the measuring beam can be defined or extended between the coupling device and the supply device.

[0039] By arranging the first and second reflectors on the common center axis, a compact structure for beam forming of the laser beam can be realized, in which the laser beam can be guided to the application material from multiple sides, especially in an annular manner. The first reflector and the second reflector are each optical deflection members. The first reflector can be set up to reflect the laser beam outward (that is, outward with respect to the axis of the center axis or the laser beam optical path). The first reflector prevents the measuring beam from being incident on the processing area or the workpiece along or parallel to the optical axis of the laser beam. The common center axis of the first reflector and the second reflector can be coaxial with the laser beam optical path or the axis of the laser beam incident on the first reflector. The first reflector can be set up to reflect the laser beam outward from a path along the optical axis and / or parallel to the optical axis. The first reflector can be set up so that the laser beam and the measuring beam are reflected outwardly onto the second reflector at an angle to the center axis.

[0040] The second reflector can be arranged concentrically with the first reflector. In other words, the center axis of the first reflector extends coaxially with the center axis of the second reflector and is referred to as the common center axis. The second reflector can be set up to reflect the laser beam rotationally symmetrically or concentrically with the center axis or optical axis of the laser beam in the direction of the processing area, for example with a cylindrical or cylindrical sleeve-shaped beam configuration or a conically converging or conical sleeve-shaped beam configuration. The second reflector can be set up to reflect the laser beam concentrically in the direction of the processing area or concentrically in the direction of the application material supplied and / or output by the supply device from multiple circumferential directions.

[0041] The first reflector is set up to reflect the laser beam and the measuring beam outwardly onto the second reflector at an angle to the center axis. The "center axis" here can particularly refer to the center axis of the first reflector and / or the second reflector. The center axis can extend coaxially with the optical path of the laser beam, in particular coaxially with the optical path of the laser beam in the beam propagation direction before the first reflector and / or the second reflector. The angle relative to the center axis can be, for example, greater than 90°, so that the outward reflection is achieved in the opposite direction. The second reflector can be arranged above the first reflector with respect to the optical path of the laser beam to the processing area and / or at the same height as the first reflector. This allows a particularly compact structure. The first reflector can be correspondingly set up so that the laser beam and the measuring beam are reflected in the opposite direction to the incident direction.

[0042] The second reflector can be configured to reflect the laser beam in the direction of the processing area, offset parallel to the central axis or at an angle to the central axis. The second reflector can be configured to reflect the laser beam concentrically and / or from multiple sides in the direction of the processing area. As a result, the laser beam can be particularly uniformly guided at the focal position to the supplied application material. By uniformly guiding the laser beam to the application material, in particular at the focal position of the laser beam, a particularly uniform melting of the application material can be achieved.

[0043] The assembly consisting of the first reflector and the second reflector can be set up to deflect or redirect the laser beam relative to the axis rotationally symmetrically of the laser beam incident on the first reflector. The redirected laser beam can have an annular cross section, that is, a cross section in which the laser beam has an intensity of approximately zero at its midpoint. The redirected measuring beam can have a circular or elliptical cross section, that is, a circular or elliptical cross section in which the measuring beam has an intensity maximum at its midpoint and / or the measuring beam continuously has an intensity greater than zero therein. The first reflector and / or the second reflector can have at least one reflective surface, in particular at least one reflective metal surface. The first reflector and the second reflector can jointly form a beam shaping optical device, which is set up to generate an annular beam profile (or annular beam configuration) of the laser beam. For example, the supply position of the applied material and / or the output opening of the applied material can be surrounded by the annular beam profile of the laser beam. The beam profile of the laser beam can converge, for example, cylindrically and / or conically, after the second reflector.

[0044] The laser beam and the measuring beam can extend in parallel in a common beam path. The laser beam and the measuring beam can extend in parallel and / or coaxially in a common beam path at least in the zero position of the measuring beam. In particular, the coupling device can be configured to couple the measuring beam into the beam path of the laser beam parallel to and / or coaxially with the laser beam.

[0045] The processing area can also be referred to as the interaction area. In the processing area, an interaction between the workpiece, the application material and the laser beam can occur. The application material can be applied or applied to the workpiece, wherein welding of the application material and the workpiece is achieved. The application material and / or the workpiece material can be melted by the energy of the laser beam. The first and second reflectors can be set up to uniformly guide the laser beam at the focal position to the supplied application material.

[0046] The laser processing head can be set up to direct a laser beam emitted by a laser source or the end of a laser guide fiber onto a processing region or a workpiece. The laser processing head can be set up to supply a laser beam to the coupling device or the first reflector, the laser beam having a circular or elliptical beam cross section and / or a (transverse) beam profile, wherein the main intensity region includes the optical axis (of the laser beam). For example, a maximum or plateau of the beam intensity can be present on the optical axis. For example, the laser processing head can be set up to direct a laser beam having a Gaussian beam profile ...

[0047] The device may also have a collimating device for collimating the laser beam. The collimating device for the laser beam may be arranged before the coupling device in the beam propagation direction of the laser beam. The collimating device for the laser beam or a part thereof may be adjusted along the optical axis of the collimating device and / or along the beam propagation direction of the laser beam in order to adjust the focal position of the laser beam.

[0048] The device can further include a laser source for generating a laser beam or can be configured to couple a laser beam from a laser source for generating a laser beam into a laser processing head, for example via a fiber coupler. A laser source can also be referred to as a laser for short. The laser can be designed as a single-mode laser, a multi-mode laser, a solid-state laser and / or a fiber laser. The device can include an optical fiber for guiding the laser beam from the laser source to the laser processing head. The device can further include an interface for transmitting data to an external system.

[0049] The device for laser cladding welding can be set up to focus the laser beam into the processing area, for example, into the focal plane, for example, into the focal point or the annular focus. Accordingly, the device can include a focusing optical device for focusing the laser beam and / or the measuring beam. The focusing optical device can be or include a lens, a focusing lens, a converging lens, a lens group, a telecentric objective lens or an f-Theta objective lens, in particular a telecentric f-Theta objective lens. The f-Theta objective lens is preferably designed not only for measuring the wavelength of the beam but also for the wavelength of the laser beam. The focusing optical device can be arranged behind the second reflector in the optical path of the laser beam. The focusing optical device can include two or more lenses, the distance between which is at least partially variable to each other in order to adjust or change the focal position.

[0050] The focusing optical device can be arranged on the common center axis in order to focus the laser beam and / or the measuring beam. The second reflector can be set up so that the laser beam and / or the measuring beam is reflected by the focusing optical device at an angle to the center axis onto the processing area. Accordingly, the focusing optical device can be set up so that the laser beam reflected by the second reflector onto the focusing optical device is directed to the processing area at an angle to the center axis. The focusing optical device can in particular include or be a focusing lens. For example, the second reflector can be set up to reflect the laser beam into a parallel beam.

[0051] The second reflector can be configured to direct the laser beam toward the processing region directly or via at least one further optical element at an angle to the central axis. The at least one further optical element can be a focusing optical device.

[0052] The second reflector can be configured to focus the laser beam and / or the measuring beam, in particular to focus with respect to the processing point and / or to focus in the processing area. The second reflector can be, for example, a (parabolic) focusing mirror. The second reflector can be, for example, an annular segment of a parabolic mirror or have a reflective surface in the form of a section of a parabola of revolution.

[0053] The control device for driving the scanning device can be set up to drive the scanning device for positioning or moving the measuring beam based on the processing direction and / or processing trajectory (especially based on the processing direction and / or processing trajectory of the device or laser processing head). Therefore, the measuring position and / or the scanning pattern can be matched and / or oriented based on the processing direction and / or processing trajectory. The control device can be set up to drive the scanning device for positioning or moving the measuring beam without or with the superposition of the scanning pattern or oscillating movement along the processing trajectory. Therefore, the positioning of the measuring beam can be realized first or later, for example, matching the current processing direction or processing trajectory. If, for example, processing is carried out in the X direction, the positioning of the measuring beam can be carried out first or later in the X direction; then if the processing direction changes and is now carried out in the Y direction, the positioning of the measuring beam can be carried out immediately in the Y direction by driving the scanning device. In particular, the control device can be set up to drive the scanning device for positioning or moving the measuring beam based on the processing direction and / or processing trajectory and the current processing position. The control device can be configured, for example, to position the measuring beam on the machining path, including a deviation from the current machining position corresponding to a predetermined time offset, in particular according to a machining speed along the machining path, or including a deviation from the current machining position corresponding to a predetermined path length along the machining path. The deviation can be, for example, 0 mm to 10 mm, in particular 1 mm to 5 mm, 0 mm to 2 mm, or 2 mm to 5 mm.

[0054] The distance measuring device can be set up to measure the distance in a previous measuring position, in a processing area (or at a processing point) and / or in a subsequent measuring position, in particular based on a processing direction and / or a processing trajectory. The control device can be set up to position the measuring beam (in particular move) based on a processing direction and / or a processing trajectory. The control device can be set up to position the measuring beam (in particular move) in advance, in a processing area (or at a processing point) and / or in the rear (relative to the current processing position), in particular based on a processing direction and / or a processing trajectory. For example, if the processing trajectory between the measuring position and the current processing position includes a turn or an angle, the distance measurement can be achieved on the processing trajectory in advance or in the rear. The corresponding positioning can be superimposed by a scanning diagram or an oscillating motion. The scanning diagram can include an oscillating motion. The control for moving the measuring beam can include a control for variably positioning the measuring beam. The movement of the measuring beam can be achieved along or on a scanning path. The scanning path can in particular include a scanning diagram.

[0055] The control device can be set up to drive the scanning device so that the measuring beam moves according to a predetermined scanning pattern or oscillating motion. The scanning pattern may include an oscillating motion. The control device can be set up to position and / or orient the scanning pattern based on the processing direction (of the laser processing head) and / or the processing trajectory. The control device can be set up to position the scanning pattern on the set measuring position based on the processing direction and / or the processing trajectory and / or orient the scanning pattern on the measuring position. The scanning pattern can be positioned on the processing trajectory accordingly, wherein the positioning can be achieved according to the processing direction and / or upstream or downstream of the processing position. The positioning is achieved with respect to the processing position. For example, the scanning pattern can be positioned according to the processing trajectory at a certain position and with a certain orientation. The scanning pattern can be configured, for example, as a line or an arc, in particular a line or an arc that is transverse to the processing trajectory or is at an angle to the processing trajectory. The scanning pattern can intersect with the processing trajectory, in particular at a right angle.

[0056] The control device can be set up to drive the scanning device to adjust and / or modify the deviation of the measuring beam from the processing position, the inclination of the measuring beam from the optical axis of the device or the focusing optical device and / or the beam diameter of the measuring beam. The measuring beam can thus be deflected, for example, offset and / or obliquely. The optical axis of the scanning device is the optical axis of the optical path of the measuring beam on the side of the scanning device on which the measuring beam enters the scanning device from the distance measuring device. The optical axis of the scanning device can correspond to the optical axis of the optical path of the laser beam on the coupling device and / or to the zero position of the offset of the measuring beam. The measuring beam can differ from the zero position at a certain time, in particular on one side.

[0057] The device may include a memory for calibration data, in particular for calibration data that take into account optical distortions of the beam path of the measuring beam through the first reflector and / or the second reflector and / or at least one optical element and / or reference height data, in particular these or other calibration data are dependent on the position of the measuring beam, the deflection of the measuring beam through the scanning device and / or the orientation of the beam deflection and / or the orientation of the coupling device and / or the orientation or setting of the scanning device. The calibration data may include reference height data and / or data for an XY calibration. In other words, the calibration data for an XY calibration or an XY plane calibration or a reference plane calibration can ensure that the position on the workpiece is correctly reflected, i.e. the measuring position can be correctly set. In addition, this coordinate system (in the Z direction) can be supplemented with reference height data. The control device can be set to drive the scanning device based on the calibration data stored in the memory to position or move the measuring beam. By correcting the optical distortion of the position on the working plane or on the workpiece surface, it can be ensured that the measurement is performed at the correct position. This is because, in order to adjust the material supply, a correct height value relative to the reference plane, i.e. a measurement value at the correct position, is required. The control device can be configured to control the scanning device to position or move the measuring beam based on calibration data stored in the memory, in particular XY calibration data and / or based on the processing direction (welding direction) and / or the processing trajectory or scanning diagram. In particular, the relationship between the position of the measuring beam or the orientation of the beam deflection (scanner and other elements) can be related to the welding direction, that is, the position of the measuring beam or the orientation of the beam deflection by the scanning device can be controlled according to the processing direction. The reference height data can, for example, vary (that is, include different values) according to the deflection of the measuring beam by the scanning device, in particular according to the deviation and / or direction of the deflection of the measuring beam. In other words, the reference height data can include or be related to the optical path length from the reference plane to the corresponding measuring position, so that changes in the path length based on the scanning position or the measuring position can be taken into account. The evaluation based on the reference height data can then make it possible to take into account changes in the optical path length of the measuring beam in the case of a changed position of the measuring beam. If, for example, a change in the deflection of the measuring beam has resulted in a different path of the measuring beam through the first and second reflectors, which has a different optical path length, then a correspondingly adjusted distance measurement can be achieved by means of the reference height data. In particular, the measuring beam can thus be positioned or moved according to the measuring position and / or a predetermined scanning pattern of the measuring beam at the measuring position, wherein an optical distortion of the measuring beam and / or a changed optical path length of the beam path can be adjusted. In particular, in each of the positioning or movement of the measuring beam described in the present disclosure, the control device can be configured to control the scanning device based on the calibration data stored in the memory in order to position or move the measuring beam.

[0058] The application material may be a wire, a powder-filled wire or a powdered application material. The application material may include at least one metal. The application material may also be referred to as a feed material. The feed device may include a wire guide. The application material may include an alloy and / or a material for forming an alloy, in particular a material for forming an alloy during laser cladding welding of the application material.

[0059] The laser processing head may be a material application head, in particular a powder application head and / or a wire application head. The laser processing head may include the supply device. The laser processing head may include the first reflector and the second reflector.

[0060] The device can be used, for example, for the following applications: laser cladding welding can include: layer application of application material, formation of a uniform connection of workpieces, application of application material in the form of powder-filled wire or wire alloy, coating of turbine blades, production of components (workpieces). For example, the workpiece can be or include a turbine blade, and laser cladding welding can include: coating the turbine blade with the application material, for example, coating with an alloy. The alloy can be produced, for example, by applying the application material in the form of powder-filled wire or wire alloy. The powder-filled wire can, for example, include a first material as wire and a second material as powder-filled wire, so that an alloy consisting of the first material and the second material can be formed during laser cladding welding.

[0061] The first reflector may be substantially conical and / or pyramidal; and / or the first reflector may have at least one reflective surface having continuous or discrete rotational symmetry about a common central axis. The first reflector may be accordingly set up to reflect the laser beam rotationally symmetrically about the central axis. The rotational symmetry may include continuous rotational symmetry (i.e. rotational symmetry for each angle) or discontinuous rotational symmetry (i.e. a plane surface for a determined uniformly distributed angular region, for example a pyramid with an equilateral base). The discontinuous rotational symmetry may be at least three times discontinuous rotational symmetry. The first reflector may be set up to deflect the laser beam rotationally symmetrically or substantially rotationally symmetrically or almost rotationally symmetrically. The first reflector may be set up to reflect the incident laser beam with an annular beam configuration (with an annular beam profile), in particular with an annularly expanded beam configuration. In other words, the laser beam has an annular beam configuration (annular beam profile) after being reflected on the first reflector. The first reflector may be set up in particular to generate an annular beam profile of the laser beam by reflection of the laser beam. The first reflector may have a cone or regular pyramid shape. The annular beam configuration or the annular beam profile may be continuously rotationally symmetrical or discontinuously rotationally symmetrical. Accordingly, the annular beam configuration or the annular beam profile may be continuously annular or annular with multiple separated and / or distanced parts, in particular at least three parts. The first reflector may have a reflective conical side. If, for example, the first reflector does not have a conical shape but a pyramidal (pyramid) shape, the beam profile may be segmented annular. The first reflector may be set up to evenly separate the laser beam in a radial direction relative to the central axis or the optical axis of the optical path. The first reflector may be arranged in the middle of the second reflector.

[0062] The second reflector may have at least one reflective surface having continuous or discrete rotational symmetry about a common central axis. Thus, the laser beam can be particularly uniformly guided to the supplied application material at the focal position. The second reflector may be set up to reflect the laser beam reflected by the first reflector in an annular beam configuration (or in an annular beam profile). The second reflector may be set up to reflect the laser beam reflected by the first reflector rotationally symmetrically about the central axis. Rotational symmetry may include continuous rotational symmetry (i.e., rotational symmetry for each angle) or discontinuous rotational symmetry (i.e., a plane surface for a determined uniformly distributed angular region, such as a pyramid with an equilateral bottom surface, or a rotational symmetry for a determined rotation angle, especially a divisor of 360°). Discontinuous rotational symmetry may be at least three times discontinuous rotational symmetry. The second reflector may be set up to deflect the laser beam rotationally symmetrically or substantially rotationally symmetrically or almost rotationally symmetrically. The annular beam configuration or annular beam profile may be a continuous annular or annular with multiple separated and / or distanced parts, especially at least three parts.

[0063] The second reflector can be annular and / or have a circular recess concentric to the central axis, which surrounds the reflective surface; and / or the second reflector can be an annular segment of a parabolic mirror. As a result, the laser beam can be particularly uniformly guided to the supplied application material at the focal position. The second reflector can have a reflective surface in the form of an annular segment of a parabola of revolution. The second reflector can have a reflective surface in the form of a portion of a parabola of revolution. The second reflector can be arranged concentrically with the first reflector and / or radially outside the first reflector. The second reflector can form a ring or have a plurality of separate parts or components. The second reflector can be straight in a radial cross section (radially with respect to the central axis) or have a curvature, in particular a concave curvature.

[0064] The first reflector and / or the second reflector can be designed to deflect the laser beam rotationally symmetrically or substantially rotationally symmetrically or almost rotationally symmetrically. As a result, the laser beam can be guided particularly uniformly at the focal position to the supplied application material.

[0065] The first reflector and / or the second reflector may have a metal surface. In particular, the first reflector and / or the second reflector may be made of metal.

[0066] The laser beam can be annular after exiting the laser processing head, and / or the measuring beam can be annular after exiting the laser processing head or move on a circular scanning path. In particular, the laser beam can have an annular beam profile after exiting the laser processing head.

[0067] The device may include an analysis device for determining the surface geometry from the distance measured by the distance measuring device, such as the height value. The surface geometry can be in particular the surface geometry along the scan image or the scan path. In particular, the surface geometry of the previous material application portion can be determined. The surface geometry may include a height profile, in particular the height profile along the scan image or the scan path and / or the height or depth of the workpiece at the measuring position on the processing track and / or the height or depth of the applied material applied at the measuring position on the processing track. The analysis device can be set up to determine the surface geometry before, in the processing area and / or after. For example, the distance measurement can be realized in the melt, for example close to the center axis or the processing point. The surface geometry can be determined by point measurement and / or by distance measurement along the scan image or the scan path.

[0068] The evaluation device can be set up to determine the height based on the surface geometry. For example, the average value of the weld bead property (height profile of the weld bead) can be determined as the height, or the height value of the weld bead property can be determined as the height. The evaluation device can be set up to identify the application edge (of the previously applied application material). Based on the preceding or succeeding surface geometry, it can be detected whether the previous material application was too high or too low. For example, the application edge can be monitored. The product (workpiece) to be generated can be monitored.

[0069] The device may include an application control device for controlling and / or regulating the material supply performed by the supply device. The application control device may be integrated into the control device or the control and analysis device. The application control device may be set up to control or regulate the material supply or material application according to the laser power of the laser beam and / or the distance measured by the distance measuring device and / or the determined surface geometry, especially according to the distance measured by the distance measuring device and / or the surface geometry on the surface position or the measuring position, which corresponds to the current processing area, and / or especially according to the distance measurement value measured by the distance measuring device before, in the processing area and / or after the measuring position and / or based on the surface geometry determined by the analysis and processing mechanism. The distance, the distance measurement value or each distance may be especially the distance, the distance measurement value or each distance measured before, in the processing area and / or after the measuring position, which corresponds to the current processing area or processing point. Regulation is understood as a control with feedback, for example, in the processing area or when measuring the distance upstream of the same processing process or in the processing area or when measuring the distance downstream of the previous processing process.

[0070] The application control device can be set up to control and / or regulate the material supply through the supply device according to the surface geometry determined by the analysis device. The application control device can be set up, for example, to adjust the possible deviation of the surface geometry from the rated height (i.e. the layer thickness to be applied) on the processing track. According to the previous measurement of the existing height or depth, the adjustment of the material supply at the current processing point can be directly realized, wherein there is no or with a time offset. The application control device can especially include a PI (proportional-integral) regulator, especially a PI regulator with a time offset. In laser cladding welding, especially corners or expansion points (Schwellpunkte) are susceptible to too much material application or too little material application or too high height or too low height. For example, the generated protrusions or other unevenness of the applied material structure can be adjusted at the corresponding position of the processing track in the next processing process. For this purpose, the distance measurement can be realized upstream of the current processing process or downstream of the previous processing process. Errors, such as deviations from the rated height, can be corrected thereby, such as the unevenness of the weld bead and / or the deviation from the rated height generated by the capillary force. In the case of a layer-by-layer application of the application material, a particularly high uniformity of the application height can thus be achieved and / or erroneous accumulations can be avoided.

[0071] The control and / or regulation of the material supply may include the control and / or regulation of the amount of applied material supplied to the processing area, the applied material flow and / or the height of the applied material structures in the processing area.

[0072] The application control device can be configured to control the power of the incident laser beam (i.e. the laser power). The application control device can be configured to control the power of the incident laser beam as a function of the material supply or together with the material supply. The application control device can thus be configured to control the power of the laser beam and / or to control the material supply and / or to drive a supply device for controlling and / or regulating the material supply, in particular in order to control and / or regulate the amount of applied material supplied to the processing area, the applied material flow and / or the height of the material structure applied in the processing area. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The present invention is described in detail below according to the accompanying drawings.

[0074] Figure 1 : A schematic diagram showing a laser cladding welding device according to an embodiment of the utility model;

[0075] Figure 2 : A schematic diagram showing a laser cladding welding device according to an embodiment of the utility model;

[0076] Figure 3 : A schematic diagram showing the position of the measurement beam on the first reflector;

[0077] Figure 4 : A schematic diagram showing the measurement beam at different moments of the scanning diagram of the measurement beam;

[0078] Figure 5 : schematically shows a scanning diagram and a height profile of the measuring beam at a previous measuring position;

[0079] Figure 6 : schematically shows the scanning diagram and height profile of the measuring beam at the subsequent measuring position;

[0080] Figure 7 : schematically shows a scanning diagram and a height profile of the measuring beam at a measuring position in a processing point; and

[0081] Figure 8 , 9 10 and 10 are schematic diagrams each showing a corresponding laser cladding welding device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0082] In the following, identical and identically acting elements are provided with the same reference numerals unless otherwise indicated.

[0083] Figure 1 A schematic diagram of a laser cladding welding device 10 according to an embodiment of the present disclosure is shown. The device 10 can be coupled to a laser source 12 for generating a laser beam 14, also referred to as a processing laser beam, so as to couple the laser beam 14 into a laser processing head 16 of the device 10. The device 10 includes a laser processing head 16 for incident and directing the laser beam 14 onto a processing area of ​​a workpiece 18.

[0084] Furthermore, the device 10 comprises a supply device 20 for application material, which is designed to supply the application material to the processing region coaxially with the laser beam 14 .

[0085] The device 10 can be configured to apply the supplied application material to the workpiece 18 by laser cladding welding or to form at least one workpiece 18 from the supplied application material by laser cladding welding. The application material can be, for example, a wire, a metal powder, or a wire filled with powder. In a plurality of processing steps, for example, a structure consisting of the application material can be formed on the workpiece 18. Figure 1 Schematically shown in FIG. 1 is the configuration of a structure, for example a wall, the height of which in the machined region of the workpiece 18 protrudes in comparison with the region to be machined.

[0086] The laser beam 14 is transmitted from the laser source 12 to the laser processing head 16 via the optical fiber 15 and is coupled into the laser processing head 16 from one end of the optical fiber 15, for example, by means of a fiber coupler. In addition, the laser processing head 16 may have a collimating optical device 22 for collimating the laser beam 14 that emanates from the end of the optical fiber 15. The focal position of the laser beam 14 may be adjusted or corrected by means of the collimating optical device 22. The focal position may be adjusted, for example, along the optical axis of the laser processing head 16. This axis may be referred to as the z-axis. The laser processing head 16 further includes a focusing device 23, which includes a focusing optical device 24 for focusing the laser beam 14 onto the processing area. The focusing optical device 24 may include a lens, for example.

[0087] The laser processing head 16 further comprises a first reflector 26 and a second reflector 28, which are concentrically arranged on a common center axis, which corresponds to the optical axis O of the laser processing head 16. The first reflector 26 is a conical reflector made of metal, and its reflective surface has continuous rotational symmetry about the common center axis. The laser beam 14 concentrically reaching the first reflector 26 is reflected outwardly by the first reflector 26 at an angle to the center axis to the second reflector 28. Therefore, the first reflector 26 splits the laser beam 14 and generates an annular beam profile of the laser beam 14.

[0088] The second reflector 28 is, for example, annular and reflects the laser beam 14 in a direction offset parallel to the central axis. The laser beam 14 reflected by the second reflector 28 can have an annular, for example cylindrical beam profile. The laser beam 14 reflected by the second reflector 28 is then focused by the focusing optical device 24 into the processing area. Therefore, the second reflector 28 reflects the laser beam 14 in the direction of the processing area through the focusing optical device 24. Therefore, the second reflector 28 is set up to reflect the laser beam 14 through the focusing optical device 24 at an angle to the central axis onto the processing area. The second reflector, for example, has a reflective surface that includes a continuous rotational symmetry about the common central axis. The second reflector 28 is annular and has a circular recess 29 concentric with the central axis. The reflective surface surrounds the circular recess 29. The second reflector is, for example, made of metal. The laser beam 14 freely directed to the processing area after passing through the focusing device 23 is directed by the focusing optical device 24 in an annular and convergent manner into the processing area and / or on the periphery of the coaxially supplied application material. The laser beam 14 freely directed onto the processing region thus has an annular beam profile, the diameter of which decreases in the direction of the processing region. The application material is melted by means of the laser beam 14 and applied to the workpiece 18 .

[0089] In order to apply cladding or material along the machining path and to irradiate the laser beam along the machining path, the device 10 also includes a positioning device 30, which can move the laser machining head 16 relative to the workpiece 18 in the x-direction, the y-direction and additionally in the z-direction. Figure 1 , which is schematically indicated in , corresponds to the (current) feed direction of the laser processing head 16 .

[0090] The device 10 further comprises a distance measuring device 34 for interferometric or optical distance measurement by means of an optical measuring beam 36. The distance measuring device 34 is designed, for example, to measure the distance between the laser processing head 16 and the workpiece 18.

[0091] According to an embodiment, the distance measuring device 34 includes optical coherence tomography or can be configured as optical coherence tomography. In other words, the distance measurement can be based on optical coherence tomography (OCT). The distance measuring device 34 includes an evaluation unit 38, which includes a broadband light source 39, such as a superluminescent diode. The light source 39 couples the measuring light into an optical fiber 40. The measuring light is divided into a reference arm 44 and a measuring arm 46 in a beam splitter 42, which is preferably configured as a fiber coupler. The measuring light of the measuring arm 46 is transmitted as an optical measuring beam 36 to a scanning device 50 via an optical fiber to deflect the measuring beam 36.

[0092] The scanning device 50 is a 2D scanning device for deflecting or offsetting the optical measuring beam 36 relative to the laser beam 14 or relative to the optical axis O of the laser processing head 16. The scanning device 50 is set up to move and deflect the optical measuring beam 36 in two directions relative to the workpiece 18. These two directions can correspond to the x-direction and the y-direction. The measuring beams 36a and 36b schematically represent the orientation of the measuring beam 36 at two different positions or at two different times. The scanning device 50 can be used to scan the surface of the workpiece 18 at a position relative to the processing position.

[0093] According to an embodiment, the scanning device 50 comprises two movable mirrors 54a, 54b, which can rotate on different rotation axes. The mirrors 54a, 54b can be designed as galvanometer mirrors. In this case, the scanning device 50 can be called a galvanometer scanner or Galvo scanner.

[0094] The scanning device 50 further comprises a beam shaping optical device 52, which comprises at least one optical lens 52a, 52b, 52c for beam expansion and / or collimation and / or focusing of the measuring beam 36. In particular, the beam shaping optical device 52 may comprise a first lens 52a for collimation of the measuring beam 36, a second lens 52b for focusing the measuring beam 36 on the scanning device 50, and a third lens 52c for re-collimation or beam expansion of the measuring beam 36.

[0095] The laser processing head 16 also includes a coupling device 56 for coupling the optical measuring beam 36 into the laser processing head 16. The coupling device 56 is set up to superimpose the optical measuring beam 36 with the laser beam 14. The coupling device 56 includes, for example, a beam splitter, which can be implemented as a dichroic mirror or can include a dichroic mirror. The beam splitter can reflect the light of the optical measuring beam 36 and allow the light of the processing laser beam 14 to pass. According to an embodiment, the (undeflected) optical measuring beam 36 and the laser beam 14 can extend parallel to each other and / or coaxially at least in sections. The coupling of the optical measuring beam 36 into the laser processing head 16 by the coupling device 56 is performed after the scanning device 50 along the beam propagation direction of the measuring beam 36 and before the first reflector 26 and the second reflector 28 in the subsequent common beam propagation orientation of the measuring beam 36 and the laser beam 14. In particular, the measuring beam 36 and the laser beam 14 pass through the first reflector 26 and the second reflector 28 in a common beam path and are reflected jointly by the first reflector 26 and by the second reflector 28 in the direction of the processing region and directed toward the processing region by the focusing optics 24 .

[0096] Since coupling device 56 is arranged downstream of scanning device 50 in the beam path of the measuring beam, optical measuring beam 36 is deflected relative to laser beam 14 by scanning device 50 .

[0097] The principle for distance measurement described here is based on the principle of optical coherence tomography, which uses the coherence properties of light by means of an interferometer. In order to measure the distance, an optical measuring beam 36 is incident on the surface of a workpiece 18. The part of the optical measuring beam 36 reflected by the surface is mapped onto the end of the optical fiber of the measuring arm 46, superimposed and interfered with the reflected part of the measuring light from the reference arm 44 in the beam splitter 42. The superimposed light contains information about the path length difference between the reference arm 44 and the measuring arm 46. This information is analyzed by the analysis unit 38. Information about the distance to the workpiece 18 or the distance between the workpiece 18 and the laser processing head 16 can be obtained from this.

[0098] According to embodiments, reference arm 44 may be designed as a dynamic reference arm, thereby allowing the measuring range of measuring device 44 to be extended.

[0099] The device 10 further comprises a control and evaluation device 60. The control and evaluation device 60 assumes the function of a control device for controlling the scanning device 50 so that the measuring beam 36 moves according to a scanning path, in particular according to a predetermined scanning pattern, or for controlling the scanning device 50 so that the measuring beam 36 moves according to a scanning path, in particular according to a predetermined scanning pattern. The scanning pattern defines, for example, the time course of the scanning path in the x-direction and the y-direction. The scanning pattern can define the time course of the scanning path relative to the processing direction.

[0100] The control and evaluation device 60 includes a memory 62 for calibration data. The calibration data take into account optical distortions and the optical path length (or reference height) of the beam path of the measuring beam 36 through the first reflector 26 and the second reflector 28. The control and evaluation device 60 can control the scanning device 50 based on the stored calibration data to position or move the measuring beam 36.

[0101] The control and evaluation device 60 also assumes the function of an evaluation device for determining the surface geometry of the workpiece 18 based on the stored reference height data and from the distances measured by the distance measuring device 34. For the current measuring position of the measuring beam 36 according to the corresponding control of the scanning device 50, the control and evaluation device 60 receives determined distance raw data, such as distances, from the evaluation unit 38. For example, the control and evaluation device 60 can determine the actual distance to the workpiece 18 or the height of the workpiece 18 at the corresponding measuring position from the distance raw data determined by the evaluation unit 38 based on the reference height data. The control and evaluation device 60 can determine the surface geometry from the corresponding measured distances based on the stored reference height data, for example, generate a height profile along a scanning path or a scanning pattern.

[0102] The control and evaluation device 60 also assumes the function of an application control device for controlling or regulating the material supply by the supply device 20. The control and evaluation device 60 is particularly designed to control the material supply as a function of the distance measured by the distance measuring device 34 or as a function of an actual distance determined based on reference height data. For example, the material supply can be carried out in advance in the machining direction by a proportional-integral controller with a time offset based on the measured distance or measured height of the workpiece 18 in order to regulate the current material application at the corresponding position of the workpiece at which the distance is measured.

[0103] In addition to the above-described deflection of the measuring beam 36 by the scanning device 50, the scanning device 50 can also be configured to adjust or modify the inclination of the measuring beam 36 with respect to the optical axis and / or the beam diameter of the measuring beam. Figure 1In the example of , the lenses 52b, 52c of the beam shaping optical device can be adjusted along the beam propagation direction in order to modify the beam diameter. For this purpose, the scanning device 50 can have corresponding adjustment drives 55b, 55c for the lenses 52b, 52c, which are driven by the control and evaluation device 60.

[0104] In the following, according to Figure 2 Describes additional embodiments that are Figure 1 The difference between the embodiments is the different configuration of the second reflector 28. In other aspects, Figure 2 The device 10 corresponds to Figure 1 The structure of the device 10.

[0105] exist Figure 2 In the embodiment of the present invention, the second reflector 28 is designed to reflect the laser beam 14 at an angle to the center axis directly in the direction of the processing area. In addition, the second reflector 28 is designed to focus the laser beam with respect to the processing point, in particular to produce a ring-shaped focus. The second reflector 28 is, for example, an annular segment of a parabolic mirror and can, for example, focus both the laser beam and the measuring beams 36a, 36b. The focusing of the laser beam 14 and the measuring beams 36a, 36b is thus performed by the curvature of the reflective surface of the second reflector 28, rather than by Figure 1 The focusing optics 24 are formed by at least one lens. The second reflector 28 reflects the laser beam 14 at an angle to the center axis in the direction of the processing area.

[0106] In the example described, the feed material is supplied to the processing region coaxially with the laser beam 14, wherein the supply of the feed material passes through the region in which the laser beam 14 is radially annularly divided into the interior of the annular beam profile of the laser beam 14, such as in Figure 1 and Figure 2 As schematically shown in FIG. 3 , the shadows of the laser beam 14 and the measuring beam 36 are thereby minimized. The supply device 20 can comprise, in this region, for example, a metal protective sheath for the supply material, which can be designed to be reflective.

[0107] exist Figure 1 and 2 In the embodiment, the coupling device 56 is configured to reflect the light of the optical measuring beams 36a, 36b and to allow the laser beam 14 to pass through. However, the present disclosure is not limited thereto. The coupling device 56 may also be configured to allow the optical measuring beams 36a, 36b to pass through and to reflect the light of the laser beam 14.

[0108] Figure 3 and Figure 4 By way of example, different deflections of measuring beam 36 at different times of scanning pattern 64 of measuring beam 36 are schematically shown. Figure 3The respective positions of measuring beam 36 on first reflector 26 along the beam propagation direction of laser beam 14 are schematically shown in a top view. Scan pattern 64 is circular, for example, and defines the circular course of the positions of measuring beam 36 about optical axis O. Figure 3 In the left part of FIG. 3 , the measuring beam 36 is located to the right of the optical axis O. Figure 4 The left part of FIG. 5 schematically shows the corresponding beam course of measuring beam 36 and of laser beam 14 in the region between coupling device 56 and workpiece 18 . Figure 3 The right part of shows the measuring beam 36 at a position to the left of the optical axis O. Accordingly, Figure 4 The right side of FIG. 5 shows the course of optical measuring beam 36 and the course of laser beam 14 in the region between coupling device 56 and workpiece 18 . In the figure, the arrows indicate the rotational movement of measuring beam 36 about optical axis O.

[0109] Figure 5 The prior distance measurement of a line-shaped scanning pattern 64 transverse to the machining path is shown by way of example and schematically. For example, the height of the workpiece 18 is obtained along the scanning pattern 64. Figure 5 The profile curve is schematically shown on the right. In the example, the scanning image 64 is arranged transversely to the applied wall structure, whose height can be determined from this height profile. During the current processing, a further layer is applied to the wall structure along the processing direction A. The material supply in the processing area B shown can be controlled at the current time based on the previously measured height for the same position of the workpiece, for example, in order to produce a course of the desired height of the structure to be applied that is as uniform as possible.

[0110] Figure 6 The measurement position is schematically shown later. Here, the height profile obtained along the scan image 64 - at Figure 6 60, until the corresponding position on the workpiece 18 is reached again in another processing process. The amount of applied material can be controlled accordingly in order to obtain, for example, a total application height of the applied material along the structure to be applied that is as uniform as possible.

[0111] exist Figure 5 and Figure 6 In the example of , the control and analysis device 60 positions the scanning image 64 based on the processing direction A and / or based on the processing path and orients the scanning image 64 accordingly. In the illustrated example of the linear scanning image 64, the orientation is, for example, transverse to the processing path. Accordingly, the control and analysis device 60 controls the scanning device 50 based on the processing direction and / or the processing path to position and move the measuring beam 36.

[0112] Figure 7An example of a circular scan pattern 64 is shown, which is positioned around the machining point or optical axis O. This example shows the structure after application, wherein the machining path (machining trajectory) includes sections in different directions. Figure 7 The right part of shows the height profile obtained along the scanning image 64 in the height direction z with respect to the swivel angle (Umlaufwickel) α of the scanning image 64. Taking into account the course of the processing path, the distance can be measured both before and after along the processing trajectory. The control and evaluation device 60 can regulate the material supply by the supply device 20 as a function of the determined height or the distance measured (before) on the processing trajectory, in order to achieve a uniform material application height along the processing trajectory, for example.

[0113] In addition to the above-described activation of the supply device 20 , the control and evaluation device for controlling the material application height can also activate the laser light source 12 , for example, in order to control the intensity of the laser beam.

[0114] Figure 5 and 6 shows the distance measurement at the measuring position before or after and Figure 7 While the distance measurement is shown at a measuring position spaced apart from the processing region, the control and evaluation device 60 can also be designed for distance measurement at a measuring position in the processing region, for example close to the optical axis O, and for regulating the material supply, for example.

[0115] exist Figure 1 and 2 In the embodiment of the present invention, instead of the conical first reflector 26, for example, a pyramidal first reflector 26 can also be used, which has a rotationally symmetrically arranged reflection surface (facet) to split the laser beam 14 and reflect it outward onto the second reflector. The second reflector 28 can be composed of annularly arranged segments, for example. In particular, the reflection surface of the first reflector and / or the second reflector can have discrete rotational symmetry.

[0116] Figure 8 Another example of the laser cladding welding device 10 according to the embodiment of the present invention is shown. Figure 8 The device 10 shown in Figure 2 The difference of the device shown in FIG. 1 is that the laser beam 14 is supplied to the laser processing head 16 by the laser source 12 via a fiber array of optical fibers 15. Therefore, the laser beam 14 includes a plurality of (sub) laser beams, which are deflected by the first reflector 26 so that the beams are radially separated and reflected onto the second reflector 28. For example, the laser beam 14 can already have an annular beam profile when passing through the coupling device 56 and when reaching the first reflector 26. The annular beam profile of the laser beam 14 is expanded by the first reflector 26 and the second reflector 28 and guided around the coaxial material supply device.

[0117] exist Fig. 9 Another embodiment of the device 10 is shown in FIG. Figure 1 The embodiment in FIG. 1 differs only in that the measuring beam 36 is only collimated and the beam shaping optical device 52 of the scanning device 50 accordingly comprises only one lens 52a for collimation. The collimated measuring beam 36 is deflected by the scanning device 50 in such a way that it does not extend completely parallel to the optical axis O. As a result, the measuring beam 36 can also reach the workpiece slightly offset from the laser beam 14. This embodiment has the advantages of being compact and simple in design.

[0118] exist Fig.10 Another embodiment of the device 10 is shown in FIG. Figure 2 The embodiment in FIG. 1 differs only in that the measuring beam 36 is similar to Fig. 9 The scanning device 50 is collimated and the beam shaping optical device 52 of the scanning device 50 accordingly comprises only one lens 52a for collimation. The collimated measuring beam 36 is deflected by the scanning device 50 so that it does not extend completely parallel to the optical axis O. As a result, the measuring beam 36 can also reach the workpiece slightly offset from the laser beam 14. This embodiment also has the advantages of being compact and simple in design.

[0119] The preferred aspects of the present invention and its particular embodiments are described below:

[0120] 1. According to the first aspect, the laser cladding welding device comprises: a laser processing head for irradiating a laser beam; a supply device for coaxially supplying an applied material; and a first reflector and a second reflector having a common center axis, wherein the first reflector is configured to reflect the laser beam outward at an angle to the center axis onto the second reflector, and the second reflector is configured to reflect the laser beam in the direction of a processing area.

[0121] 2. The device according to item 1, wherein the first reflector and the second reflector are arranged before the supply device along the beam propagation direction of the laser beam.

[0122] 3. The device according to item 1 or 2, wherein the second reflector is configured to reflect the laser beam in the direction of the processing region, offset in parallel to the center axis or at an angle to the center axis.

[0123] 4. The device according to item 1, 2 or 3, wherein the second reflector is designed to focus the laser beam and / or the measuring beam with respect to the processing point.

[0124] 5. The device according to number 1, 2, 3 or 4 also includes: an application control device for controlling and / or adjusting material supply and / or laser power.

[0125] 6. The device according to any one of numbers 1 to 5, wherein the application material is a wire, a wire filled with powder or an application material in powder form.

[0126] 7. The device according to any one of numbers 1 to 6, wherein the first reflector is substantially conical and / or pyramidal.

[0127] 8. The device according to any one of numbers 1 to 7, wherein the first reflector has at least one reflective surface having a continuous or discrete rotational symmetry about a common central axis.

[0128] 9. The device according to any one of numbers 1 to 8, wherein the second reflector has at least one reflective surface having a continuous or discrete rotational symmetry about a common central axis.

[0129] 10. The device according to any one of numbers 1 to 9, wherein the second reflector is annular and / or has a circular recess concentric with the central axis, which surrounds the reflective surface.

[0130] 11. The device according to any one of numbers 1 to 10, wherein the second reflector is a ring segment of a parabolic mirror.

[0131] 12. The device according to any one of numbers 1 to 11, wherein the first reflector and / or the second reflector is made of metal.

[0132] 13. The device according to any one of numbers 1 to 12, wherein the laser beam is annular after exiting the laser processing head.

[0133] 14. The device according to one of numbers 1 to 13, further comprising: a distance measuring device for measuring the distance by means of a measuring beam; and a scanning device for deflecting the measuring beam.

[0134] 15. The device according to item 14, further comprising: a coupling device for coupling the optical path of the measuring beam into the optical path of the laser beam.

[0135] 16. The device according to item 15, wherein the first reflector and the second reflector are arranged between the coupling device and the supply device and are located in a common beam path of the laser beam and the measuring beam.

[0136] 17. The device according to item 14, 15 or 16, further comprising: a control device for controlling the scanning device, wherein the control device is configured to control the scanning device to position or move the measuring beam.

[0137] 18. A device according to number 14, 15, 16 or 17, wherein the device includes a memory for calibration data, wherein the calibration data takes into account optical distortions and / or optical path lengths of the optical path of the measuring beam, in particular the optical path lengths of the optical path of the measuring beam through a first reflector and / or through a second reflector and / or through another optical component.

[0138] 19. The device according to item 18, wherein the control device is configured to control the scanning device based on XY calibration data stored in the memory to position or move the measuring beam.

[0139] 20. The device according to item 18 or 19, wherein the distance measuring device is configured to determine the relative height at the respective measuring position based on reference height data stored in a memory and the measured distance.

[0140] 21. Device according to item 14, 15, 16, 17, 18, 19 or 20, wherein the distance measuring device is designed to measure the distance at a preceding, in the processing area and / or at a subsequent measuring position.

[0141] 22. The device of claim 14, 15, 16, 17, 18, 19, 20 or 21, wherein the ranging device comprises an optical coherence tomography (OCT) device or a time-of-flight (ToF) sensor.

[0142] 23. The device according to number 14, 15, 16, 17, 18, 19, 20, 21 or 22 also includes: an analysis device for determining the surface geometry from the distance measured by the distance measuring device.

[0143] 23. The device according to any one of numbers 1 to 22, further comprising: a focusing optical device, which is arranged on the common central axis to focus the laser beam.

[0144] 24. The device according to item 23, wherein the second reflector is configured to reflect the laser beam via the focusing optical device onto the processing area at an angle to the central axis.

[0145] 25. The device according to item 14, 15, 16, 17, 18, 19, 20, 21 or 22, further comprising: a focusing optical device which is arranged on a common center axis in order to focus the laser beam and / or the measuring beam.

[0146] 26. The device according to item 25, wherein the second reflector is designed to reflect the laser beam and / or the measuring beam via the focusing optical device onto the processing area at an angle to the center axis.

[0147] 27. The device according to number 14, 15, 16, 17, 18, 19, 20, 21, 22, 25 or 26 also includes: an application control device for controlling and / or adjusting the laser power and / or the material supply of the supply device according to the distance measured by the distance measuring device and / or according to the surface geometry determined by the distance measured by the distance measuring device.

[0148] 28. The device for laser cladding welding according to the second aspect includes: a laser processing head 16 for incident laser beam 14; a distance measuring device 34 for measuring distance by means of measuring beam 36; a scanning device 50 for deflecting the measuring beam 36; a coupling device 56 for coupling the optical path of the measuring beam 36 into the optical path of the laser beam 14; a supply device 20 for coaxially supplying the applied material; and a first reflector 26 and a second reflector 28, wherein the first reflector and the second reflector have a common central axis and are arranged between the coupling device 56 and the supply device 20 in the common optical path of the laser beam 14 and the measuring beam 36; wherein the first reflector 26 is set up to reflect the laser beam 14 and the measuring beam 36 outward at an angle to the central axis onto the second reflector 28; and wherein the second reflector 28 is set up to reflect the laser beam 14 in the direction of the processing area.

[0149] 29. The device according to number 28, wherein the second reflector 28 is configured to reflect the laser beam 14 in a direction of a processing area, offset parallel to the center axis or at an angle to the center axis.

[0150] 30. The device according to item 28 or 29, wherein the second reflector 28 is designed to focus the laser beam 14 and / or the measuring beam 36 with respect to a processing point.

[0151] 31. The device according to one of numbers 28, 29 or 30 further includes: a control device 60 for driving the scanning device 50, wherein the control device 60 is configured to drive the scanning device 50 based on a processing direction and / or a processing trajectory to position or move the measuring beam 36.

[0152] 32. The device according to number 31, wherein the control device 60 is configured to drive the scanning device 50 so that the measuring beam 36 moves according to a predetermined scanning pattern 64, wherein the control device 60 is configured to position and / or orient the scanning pattern 64 based on a processing direction and / or a processing trajectory.

[0153] 33. An apparatus according to number 31 or 32, wherein the apparatus 10 includes a memory 62 for calibration data, wherein the calibration data takes into account optical distortion and / or optical path length of the optical path of the measuring beam 36 through the first reflector 26 and / or through the second reflector 28 and / or through another optical component, wherein: the control device 60 is configured to drive the scanning device 50 to position or move the measuring beam 36 based on reference height data stored in the memory 62; and / or the distance measuring device 34 is configured to determine the relative height at the corresponding measuring position based on the reference height data stored in the memory 62 and the measured distance.

[0154] 34. The device according to any of numbers 28 to 33, wherein the distance measuring device 34 is designed to measure distances at a preceding measurement position, in the processing area and / or at a subsequent measurement position.

[0155] 35. The device according to any one of numbers 28 to 34, further comprising: an analysis device 60 for determining a surface geometry from the distance measured by the distance measuring device 34.

[0156] 36. The device according to any one of numbers 28 to 35, wherein the distance measuring device 34 comprises an optical coherence tomography (OCT) device or a time-of-flight (ToF) sensor.

[0157] 37. The device according to any one of numbers 28 to 36, wherein the application material is an application material in the form of a wire, a powder-filled wire or a powder.

[0158] 38. An apparatus according to one of numbers 28 to 37, wherein the first reflector 26 is substantially conical and / or pyramidal; and / or the first reflector 26 has at least one reflective surface having continuous or discrete rotational symmetry about a common central axis.

[0159] 39. The device according to any one of numbers 28 to 38, wherein the second reflector 28 has at least one reflective surface having continuous or discrete rotational symmetry about a common central axis.

[0160] 40. The device according to any one of numbers 28 to 39, wherein the second reflector 28 is annular and / or has a circular recess 29 concentric with the central axis, which surrounds the reflecting surface, and / or the second reflector 28 is an annular segment of a parabolic mirror.

[0161] 41. The device according to any one of numbers 28 to 40, wherein the first reflector 26 and / or the second reflector 28 is made of metal.

[0162] 42. An apparatus according to one of numbers 28 to 41, wherein the apparatus further comprises a focusing optical device 24, which is arranged on a common center axis so as to focus the laser beam 14 and / or the measuring beam 36, and wherein the second reflector 28 is set up so that the laser beam 14 and / or the measuring beam 36 is reflected by the focusing optical device 24 onto a processing area at an angle to the center axis.

[0163] 43. The device according to any of numbers 28 to 42, wherein the laser beam 14 is annular after exiting the laser processing head 16.

[0164] 44. The device according to one of numbers 28 to 43 also includes: an application control device 60, which is used to control and / or adjust the material supply and / or laser power performed by the supply device 20 according to the distance measured by the distance measuring device 34 and / or according to the surface geometry determined by the distance measured by the distance measuring device 34.

[0165] List of reference numerals:

[0166] 10Device for laser cladding welding

[0167] 12 Laser Source

[0168] 14 Laser beam

[0169] 15 Optical fiber

[0170] 16 Laser processing heads

[0171] 18 Workpieces

[0172] 20 Supply device

[0173] 22Collimation Optics

[0174] 23 Focusing device

[0175] 24 Focusing optical equipment

[0176] 26First reflector

[0177] 28 Second reflector

[0178] 29 vacancies

[0179] 30 Positioning device

[0180] 34 Distance measuring device

[0181] 36 Measurement beam

[0182] 38Analysis and processing unit

[0183] 39 Light Source

[0184] 40 optical fiber

[0185] 42 beam splitter

[0186] 44 Reference Arm

[0187] 46 measuring arm

[0188] 50 Scanning device

[0189] 52Beam shaping optics

[0190] Lenses 52a, 52b, 52c

[0191] 52c Collimating Lens

[0192] Mirror 54a, 54b

[0193] 55b, 55c regulating driver

[0194] 56 coupling device

[0195] 60 Control and analysis processing device

[0196] 62 Memory

[0197] 64 scans

[0198] 70 Scanning device

[0199] 72a, 72b scanning mirrors.

Claims

1. A device for laser cladding welding, It is characterized in that The device includes: a laser processing head for causing a laser beam to be incident; a supply device for coaxially supplying application material; and A first reflector and a second reflector, wherein the first reflector and the second reflector have a common central axis, wherein the first reflector is configured to reflect the laser beam outwardly at an angle to the central axis onto the second reflector, and the second reflector is configured to reflect the laser beam toward a processing area.

2. The device according to claim 1, It is characterized in that The first reflector and the second reflector are arranged in front of the supply device along a beam propagation direction of the laser beam.

3. The device according to claim 1, It is characterized in that The second reflector is configured to reflect the laser beam in a direction of a processing area while being offset from the central axis or at an angle to the central axis.

4. The device according to any one of claims 1 to 3, It is characterized in that The second reflector is configured to focus the laser beam about a processing point.

5. The device according to any one of claims 1 to 3, It is characterized in that The device also includes: Application control device for controlling and / or regulating material supply and / or laser power.

6. The device according to any one of claims 1 to 3, It is characterized in that The first reflector has at least one reflective surface having continuous or discrete rotational symmetry about a common central axis; and / or The second reflector has at least one reflective surface, and the reflective surface has continuous or discrete rotational symmetry about a common central axis.

7. The device according to any one of claims 1 to 3, It is characterized in that The second reflector is annular and has a circular opening concentric with the central axis, the circular opening surrounding the reflective surface.

8. The device according to any one of claims 1 to 3, It is characterized in that The laser beam is annular after exiting the laser processing head.

9. The device according to claim 1, It is characterized in that The device also includes: a distance measuring device for measuring distances by means of a measuring beam; and A scanning device for deflecting the measuring beam.

10. The device according to claim 9, It is characterized in that The device also includes: Coupling means for coupling the optical path of the measuring beam into the optical path of the laser beam.

11. The device according to claim 10, It is characterized in that The first and second reflectors are arranged between the coupling device and the supply device in a common beam path of the laser beam and the measuring beam.

12. The device according to any one of claims 9 to 11, It is characterized in that The device comprises a memory for calibration data, wherein the calibration data take into account optical distortions and / or optical path lengths of the optical path of the measuring beam through the first reflector and / or through the second reflector and / or through further optical components.

13. The device according to claim 12, It is characterized in that The device also includes: A control device for controlling the scanning device, wherein the control device is arranged to control the scanning device to position or move the measuring beam based on XY calibration data stored in the memory.

14. The device according to any one of claims 9 to 11, It is characterized in that The distance measuring device is provided to measure the distance at a preceding measuring position, in the processing area and / or at a subsequent measuring position.

15. The device according to any one of claims 9 to 11, It is characterized in that The device also includes: An evaluation device (60) is provided for determining the surface geometry from the distance measured by the distance measuring device.

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