Nozzle for a laser welding device, laser welding device with the same and method for laser welding

Abstract

A nozzle for coaxial shielding gas supply for a laser welding device is described. The nozzle comprises: a nozzle body with a gas inlet; and a nozzle tip with a nozzle opening for the gas outlet. The nozzle body includes a first connection area for connecting the nozzle body to a laser welding head of the laser welding device and a second connection area. The nozzle tip includes a third connection area. The second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip are inserted into one another and fastened to each other by means of at least two screw elements such that the nozzle tip is attached to the nozzle body in a replaceable and / or slidable manner by means of the screw elements. A laser welding device and a method for laser welding are also described.

Description

[0001] The present invention relates to a nozzle for a laser welding device, a laser welding device with such a nozzle, and a method for laser welding with such a nozzle or such a laser welding device. The present invention can be used in particular for laser wire welding or laser wire cladding. Technical background

[0002] To process a workpiece using a laser beam (laser processing or laser machining), a laser processing device is used, which includes a laser processing head for directing the laser beam onto the workpiece. The laser processing head can include beam guidance and beam shaping optics. Furthermore, the laser processing head can include focusing optics for focusing the laser beam onto the workpiece. A laser light source is used to generate the laser beam. The laser beam can be guided to the laser processing head by means of an optical fiber.

[0003] The laser processing method can be laser welding, for example, laser cladding, in particular laser wire cladding. In laser welding, the laser processing device can also be called a laser welding device and the laser processing head a laser welding head. In laser wire cladding, a wire-shaped (cladding) material is melted by means of a laser beam and bonded to at least one workpiece (also called a substrate). This allows, for example, structures to be welded onto the workpiece. Furthermore, several workpieces can be welded together using the material. The laser processing head directs the laser beam into a processing area (also called the process zone) on the workpiece. A wire feed device feeds the wire (also called the welding wire) into the processing area. The wire feed device can be arranged on or in the laser processing head.be part of the same. In coaxial laser (wire) cladding, the wire is melted using one or more coaxially supplied laser beams.

[0004] To prevent oxidation of the coating material or the workpiece material, shielding gas is regularly supplied, with a distinction made between lateral (i.e., sideways) and coaxial shielding gas supply. Empirical studies have shown that gas consumption is lower with lateral supply than with coaxial supply. On the other hand, lateral supply creates a directional dependency, which can cause, for example, welded structures to tilt along the flow direction of the shielding gas, which is generally undesirable.

[0005] Therefore, a coaxial shielding gas supply is often used, which avoids this problem. With a coaxial shielding gas supply, the shielding gas is introduced via a shielding gas nozzle (or simply nozzle). The nozzle has a nozzle tip through which, in addition to the shielding gas flow, the laser beam and, if applicable, the supplied wire also exit to enter the process zone.

[0006] The shielding gas flow should exhibit high coaxiality with the laser beam or the fed wire. While the laser beam and the wire can usually be adjusted separately and thus independently of each other, this is not possible for the shielding gas flow. Therefore, there is a lack of freedom for adjusting the shielding gas flow. In particular, the nozzle cannot be adjusted separately. Consequently, the coaxiality between the shielding gas flow and the laser beam, or between the shielding gas flow and the fed wire, is influenced or determined by the manufacturing tolerances of the nozzle and the settings of the laser beam or wire, respectively.

[0007] To minimize gas consumption, the nozzle tip and the outlet for the shielding gas are positioned as close as possible to the process zone. However, this proximity to the process zone leads to increased wear and tear from heat, weld spatter, and similar factors. Simultaneously, the shielding gas flow should be laminar, which requires the nozzle tip and orifice to be as free of damage as possible. Laminar flow is desirable to avoid turbulence, which would lead to undesirable mixing of the shielding gas with the atmosphere. Therefore, coaxial shielding gas supply presents two conflicting requirements.

[0008] To address this, current nozzles for shielding gas supply are mostly designed in two parts, allowing the lower part to be replaced as a wear part. This wear part is screwed into the upper part of the nozzle via a thread. With these current designs, replacement within a system is often difficult, as the lower part must be screwed into the upper part from below by turning it over one or more threads, requiring good accessibility. Summary of the invention

[0009] It is an object of the present invention to improve a nozzle for coaxial shielding gas supply in laser welding, particularly in laser wire welding or laser wire cladding. It is a further object to provide a nozzle that allows separate adjustment of the nozzle, in particular separate adjustment of the nozzle tip. It is a further object to provide a nozzle that allows the shielding gas flow to be adjusted separately and coaxially, in particular with respect to the laser beam and, optionally, to a supplied wire.

[0010] Furthermore, it is a task to specify a nozzle that allows for simplified interchangeability of a nozzle tip and / or other parts of the nozzle, for example a nozzle body.

[0011] Furthermore, the task is to specify a laser welding device with such a nozzle, and a method for laser welding with such a nozzle or such a laser welding device.

[0012] At least one of these problems is solved by the subject matter of the independent claims. Preferred embodiments are defined by the corresponding dependent claims.

[0013] According to one aspect of the present invention, a nozzle for coaxial shielding gas supply for a laser welding device is provided, the nozzle comprising: a gas inlet; a nozzle body; and a nozzle tip with a nozzle opening for the gas outlet. The nozzle body comprises a first connection area for connecting the nozzle body to a laser welding head of the laser welding device and a second connection area; the nozzle tip comprises a third connection area. The second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip are inserted into one another. The second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip are fastened to one another by means of at least two screw elements such that the nozzle tip is attached to the nozzle body in a manner that allows it to be replaced and / or slidably moved by means of the screw elements.

[0014] According to a further aspect of the present invention, a nozzle for coaxial shielding gas supply for a laser welding device is specified, the nozzle comprising: a gas inlet; a nozzle body; and a nozzle tip with a nozzle opening for the gas outlet, wherein the nozzle body comprises a first connection area for connecting the nozzle body to a laser welding head of the laser welding device and a second connection area, and the nozzle tip comprises a third connection area. The second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip are inserted into one another. The second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip can be fastened to one another, for example by means of two screw elements, such that the nozzle tip is removable and / or replaceable and / or that the nozzle tip and the nozzle body are adjustable relative to each other, in particular, displaceable.

[0015] According to a further aspect of the present invention, a nozzle for coaxial shielding gas supply for a laser welding device is specified, the nozzle comprising: a gas inlet; a nozzle body; and a nozzle tip with a nozzle opening for the gas outlet, wherein the nozzle body comprises a first connection area for connecting the nozzle body to a laser welding head of the laser welding device and a second connection area, wherein the nozzle tip comprises a third connection area. The second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip are connected to each other.

[0016] According to another aspect of the present disclosure, a laser welding device for laser welding using a laser beam is specified, the laser welding device comprising: a laser welding head configured for shining the laser beam, and a nozzle for coaxial shielding gas supply according to one of the preceding claims, which is attached to the laser welding head.

[0017] According to another aspect of the present disclosure, the use of a laser welding device according to aspects and embodiments for a laser welding method, in particular for laser wire welding or laser wire cladding welding, is specified.

[0018] Shielding gas is drawn into and through an internal chamber of the nozzle, formed in the nozzle body or nozzle tip, via the gas inlet, and exits the nozzle through the nozzle opening. The laser beam enters the nozzle through the first connection area and exits through the nozzle opening. If a wire is fed for wire (cladding) welding, the wire can be inserted into the nozzle through the first connection area and exit through the nozzle opening. The wire can be fed centrally through the nozzle.

[0019] The present disclosure thus provides a two-part nozzle comprising the nozzle body and the nozzle tip. The gas inlet can be located in the nozzle body or in the nozzle tip. The nozzle tip can be attached to the nozzle body in a replaceable manner. This allows the nozzle tip to be easily replaced, for example, if it becomes dirty. Furthermore, the nozzle tip can be attached to the nozzle body in a way that allows for adjustment. The nozzle opening can be adjustable or aligned relative to the nozzle body and / or relative to the laser beam and, if applicable, relative to the fed wire. Thus, the nozzle opening can be adjusted to be coaxial with the laser beam and / or the wire. Consequently, the flow of shielding gas exiting the nozzle opening can be adjusted to be coaxial with the laser beam or the fed wire. Due to the two-part design of the nozzle, the nozzle body itself can also be easily replaced.

[0020] In contrast to existing solutions where the nozzle tip is attached to the nozzle body by a thread, the nozzle according to the present disclosure can be attached or replaced more easily. Furthermore, an additional degree of freedom is provided to adjust the nozzle opening laterally to the laser beam or the fed wire.

[0021] A coaxial shielding gas supply can mean that the shielding gas exiting the nozzle orifice flows coaxially to the beam axis of the laser beam and / or coaxially to a longitudinal axis of the supplied wire (if wire is supplied), particularly at the exit of the nozzle orifice. The flow of the shielding gas can be essentially rotationally symmetric. In this case, an axis of symmetry of the shielding gas flow can coincide with the beam axis of the laser beam or with the axis of the wire. The laser beam can be split into several partial beams by means of the laser welding head, whereby the several partial beams can be arranged rotationally symmetrically and / or rotationally symmetrically about an axis of symmetry. In this case, the (common) axis of symmetry of the several partial beams can be referred to as the "beam axis of the laser beam".The longitudinal axis of the wire can coincide with a wire guidance direction and / or with the beam axis of the laser beam and / or with the central axis of the nozzle tip in an interior of the nozzle and / or when exiting the nozzle opening.

[0022] The gas inlet of the nozzle body serves to introduce shielding gas into an interior of the nozzle, or into an interior of the nozzle body or nozzle tip. The nozzle body can also be referred to as an adapter. The nozzle tip is designed as a component of the nozzle and encompasses the nozzle opening at its end.

[0023] When elements are described as "adjustable," "movable," or "adjustable," this also includes the fact that the elements can be adjusted, moved, or set. The term "relative to" is synonymous with "opposite." The protective gas may subsequently also be referred to simply as "gas."

[0024] The aspects and embodiments may include one or more of the following optional features: The interior of a nozzle can be essentially rotationally symmetrical. It can be formed by the interior of the nozzle body and / or the nozzle tip. The interior of the nozzle can function as a pressure chamber for the shielding gas.

[0025] The interior of the nozzle body can be essentially rotationally symmetrical. The interior of the nozzle tip can also be essentially rotationally symmetrical. An axis of symmetry of the interior of the nozzle body can be a central axis of the nozzle body. An axis of symmetry of the interior of the nozzle tip can be a central axis of the nozzle tip. The central axis of the nozzle body and the central axis of the nozzle tip can be parallel to each other.

[0026] The nozzle opening can be defined in a plane perpendicular to the central axis of the nozzle tip. The nozzle opening can be essentially rotationally symmetric and / or circular. The center point of the nozzle opening can lie on the axis of symmetry of the interior of the nozzle tip or on the central axis of the nozzle tip.

[0027] The screw elements can be screws, in particular set screws, or comprise them. The screw elements can be arranged coplanarly to one another. In this arrangement, either the ends of the screw elements and / or their longitudinal or central axes can lie in the same plane. A longitudinal or central axis of each screw element can run in a plane perpendicular to the central axis of the nozzle, or it can be inclined to this plane or the central axis of the nozzle. An imaginary extension of the central axis of each screw element can intersect the central axis of the nozzle tip and / or the central axis of the nozzle body.

[0028] The second connection area of ​​the nozzle body can be inserted into the third connection area of ​​the nozzle tip. In this case, the third connection area can be fitted over or overlap the second connection area. Alternatively, the third connection area of ​​the nozzle tip can be inserted into the second connection area of ​​the nozzle body. In this case, the second connection area can be fitted over or overlap the third connection area.

[0029] The screw elements can connect or fasten the nozzle body and nozzle tip to each other via frictional and / or detachable fastening. For this purpose, the screw elements can exert a force (in particular a pressing force) on the inner connection area of ​​the second and third connection areas to fasten the nozzle body and nozzle tip. One connection area selected from the second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip, in particular the outer connection area (in the radial direction of the nozzle or nozzle body or nozzle tip), can have through holes with an internal thread. One of the screw elements can pass through or be screwed through each of these through holes.Each of the screw elements can rest with its (inner) end on or press against the other connection area selected from the second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip, in particular the inner connection area. Each of the screw elements can have an external thread that can be screwed into the through-hole.

[0030] In other words, the outer of the two connection areas can have through holes with internal threads. If the second connection area of ​​the nozzle body is received or inserted into the third connection area of ​​the nozzle tip, the third connection area of ​​the nozzle tip can have through holes with internal threads. The screw elements can penetrate or be "screwed through" the third connection area of ​​the nozzle tip and rest with their ends on or press against the second connection area of ​​the nozzle body, so that the second and third connection areas are fastened together. This creates a force-fit connection or fastening between the second and third connection areas along the central axis of the nozzle tip or nozzle body.

[0031] When the third connection area of ​​the nozzle tip is received or inserted into the second connection area of ​​the nozzle body, the second connection area of ​​the nozzle body can have through holes with internal threads through which the screw elements are inserted or "screwed in." With their ends (axially speaking) located internally, the screw elements can rest on or press against the third connection area of ​​the nozzle tip, thus securing the second and third connection areas together. This creates a force-fit connection between the second and third connection areas along the central axis of the nozzle tip or nozzle body.

[0032] The nozzle can include at least one spring element. The spring element can be arranged between the second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip. The spring element can be configured to provide an elastic restoring force between the nozzle body and the nozzle tip. The elastic restoring force can include at least one force component or force vector that runs parallel to, but opposite to, a force exerted on the second or third connection area by at least one of the screw elements. A force vector of the restoring force can intersect the central axis of the nozzle body or nozzle tip and / or can run perpendicular to or inclined to it.

[0033] The nozzle can have exactly two screw elements and exactly one spring element. The two screw elements and the one spring element can be arranged circumferentially around the nozzle body and / or around the central axis of the nozzle body at an angle of 120° to each other.

[0034] The nozzle can have exactly three screw elements. The three screw elements can be arranged circumferentially around the nozzle body and / or around the central axis of the nozzle body at an angle of 120° to each other.

[0035] The nozzle can have exactly two screw elements and exactly two spring elements. The two screw elements and the two spring elements can be arranged circumferentially around the nozzle body and / or around the central axis of the nozzle body at an angle of 90° to each other. Each screw element can be opposite each spring element, e.g., with respect to the central axis of the nozzle body and / or in a plane perpendicular to it.

[0036] The nozzle can have exactly four screw elements. The four screw elements can be arranged circumferentially around the nozzle body and / or around the central axis of the nozzle body at an angle of 90° to each other. The four screw elements can be arranged in pairs opposite each other, e.g., with respect to the central axis of the nozzle body and / or in a plane perpendicular to it.

[0037] The screw elements (possibly together with the spring elements) can be the sole means of fastening between the nozzle body and the nozzle tip. In other words, by loosening the screw elements, the fastening between the nozzle body and the nozzle tip can be released and / or the nozzle tip can be removed from the nozzle body. The nozzle tip can therefore be attached to the nozzle body in a replaceable manner using the screw elements.

[0038] The nozzle tip and the nozzle body can be adjustable and / or displaceable relative to each other, in particular along at least one axis (preferably along two mutually perpendicular axes) and / or in a plane perpendicular to the central axis of the nozzle tip and / or the central axis of the nozzle body. The at least one axis can run in a plane perpendicular to the central axis of the nozzle tip and / or the central axis of the nozzle body. The nozzle tip and the nozzle body can be adjustable or displaceable relative to each other by means of the screw elements. The nozzle tip can be adjustable or displaceable relative to the nozzle body. The nozzle body can be adjustable or displaceable relative to the nozzle tip.

[0039] The position of the nozzle opening can be adjustable or displaceable relative to the central axis of the nozzle body. This allows the position of the nozzle opening relative to the nozzle body to be adjusted, particularly in a plane perpendicular to the central axis of the nozzle body and / or in a plane perpendicular to the central axis of the nozzle tip. The position of the nozzle opening can be defined as the position of the center point of the nozzle opening. Since the shielding gas exits through the nozzle opening, the adjustability or displaceability of the nozzle opening relative to the central axis of the nozzle body allows the shielding gas supply or flow to be adjusted separately, particularly independently of the laser beam and, if applicable, the fed wire, and especially coaxially to the laser beam and, if applicable, to the fed wire. This ensures a coaxial shielding gas supply.

[0040] The central axis of the nozzle body and the central axis of the nozzle tip can be adjustable or displaceable relative to each other or relative to each other, in particular along at least two axes and / or in a plane perpendicular to the central axis of the nozzle and / or to the central axis of the nozzle body and / or to the central axis of the nozzle tip, especially by means of screw elements. The central axis of the nozzle tip, in particular the center point of the nozzle opening, can be adjustable or displaceable relative to the central axis of the nozzle body. The central axis of the nozzle body can be adjustable or displaceable relative to the central axis of the nozzle tip. The central axis of the nozzle tip, in particular the center point of the nozzle opening, can be adjustable coaxially with the central axis of the nozzle body.

[0041] The nozzle tip can be adjustable or displaceable relative to the laser beam (especially to the beam axis of the laser beam) and / or relative to the fed wire (especially to the axis of the fed wire). The nozzle tip can be adjustable or displaceable in a plane perpendicular to the beam axis of the laser beam and / or in a plane perpendicular to the axis of the fed wire and / or in a plane perpendicular to the central axis of the nozzle tip. The nozzle tip can be displaceable by means of the screw elements. The position of the nozzle opening can be adjustable relative to the beam axis of the laser beam and / or relative to the axis of the fed wire, especially in a plane perpendicular to the beam axis of the laser beam and / or in a plane perpendicular to the axis of the wire. The position of the nozzle opening can be set coaxially to the beam axis of the laser beam and / or to the axis of the fed wire.

[0042] The central axis of the nozzle tip, in particular the center of the nozzle opening, can be adjustable or displaceable relative to the beam axis of the laser beam and / or relative to the axis of the fed wire. The central axis of the nozzle tip can be adjusted to be coaxial with the beam axis of the laser beam or coaxial with the axis of the fed wire. In other words, the position of the nozzle tip can be adjusted so that the center of the nozzle opening lies on the beam axis of the laser beam or on the axis of the fed wire.

[0043] An external connection area, selected from the second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip, may have an inner diameter that is 1 to 2 mm larger than the outer diameter of an internal connection area, also selected from the second connection area of ​​the nozzle body and the third connection area of ​​the nozzle tip. This ensures sufficient clearance for adjusting the position of the nozzle tip.

[0044] The first, second, and / or third connection area can be single-walled and / or solid (i.e., ring-shaped solid). Likewise, the nozzle body and / or nozzle tip can be single-walled overall. The nozzle body and / or nozzle tip can be hollow, i.e., with an interior space. In particular, a wall of the nozzle body adjacent to the interior space of the nozzle body and / or a wall of the nozzle tip adjacent to the interior space of the nozzle tip can be single-walled. The wall thickness of the nozzle body can be between 5 mm and 10 mm, particularly between 7 mm and 9 mm, preferably 8 mm. The wall thickness of the nozzle body can vary along the central axis of the nozzle body and / or can increase between the first and second connection areas.The thickness of the nozzle body wall can be defined along a normal to the wall surface of the nozzle body bounding the interior and / or as the shortest distance between the inner surface of the wall adjacent to the interior of the nozzle body and an outer surface of the wall.

[0045] The first and / or second connection area can be formed as a stepped offset in the nozzle body, particularly in the wall of the nozzle body. The first connection area can be formed at a first end section of the wall of the nozzle body. The first connection area can be formed as a stepped offset in the wall of the nozzle body, particularly at the first end section of the wall. The first connection area can be formed as a projection, collar, or flange extending from the wall of the nozzle body in a direction perpendicular to the central axis of the nozzle body.

[0046] The second connection area can be formed at a second end section of the nozzle body. The second connection area can be formed as a stepped offset in the wall of the nozzle body, particularly on the outside and / or inside of the wall. The second connection area can be formed by a recess in the wall of the nozzle body and / or as a flange. In particular, when the second connection area is inserted or plugged into the third connection area, it can have a smaller (outer) diameter than a main section of the nozzle body.

[0047] The third connection area can be formed as a stepped offset in the wall of the nozzle tip, particularly on the outside and / or inside of the wall. The third connection area can be formed by a recess in the wall of the nozzle tip and / or as a flange. The second and third connection areas can overlap along the central axis of the nozzle tip and / or along the central axis of the nozzle body. The second and third connection areas can be arranged as concentric rings in a cross-sectional plane perpendicular to the central axis of the nozzle tip and / or the central axis of the nozzle body.

[0048] The first, second, and / or third connection area can be annular and / or hollow cylindrical. The first, second, and / or third connection area can surround a region of the interior of the nozzle body or nozzle tip and / or partially delimit or define the interior of the nozzle body or nozzle tip.

[0049] The laser beam can enter the nozzle body through an opening in the first connection area and exit the nozzle body through an opening in the second connection area. The laser beam can enter the nozzle tip through an opening in the third connection area and exit the nozzle tip through the nozzle opening. The same applies to the supplied wire.

[0050] The nozzle may include a cooling device for cooling the nozzle, in particular the nozzle body and / or the nozzle tip. The cooling device may be arranged on or attached to an outer surface of the nozzle body, in particular to an outer surface of the nozzle body wall. The cooling device may be removable and / or replaceable. The cooling device may be an active cooling device for cooling the nozzle by means of a cooling medium. The cooling device may be an active cooling device for cooling the nozzle by means of a cooling medium flowing through or in the cooling device, e.g., a gas (such as air) or a liquid (such as water). The cooling device may have cooling medium connections for connection to a cooling medium circuit. The cooling device may also be a passive cooling device for cooling the nozzles, for example, by means of convection.

[0051] The nozzle body and / or nozzle tip may consist of or comprise at least one of the following materials: a material with a thermal conductivity of more than 50 W / (m*K) or more than 70 W / (m*K), preferably more than 100 W / (m*K) or more than 120 W / (m*K), particularly preferably more than 200 W / (m*K), aluminum, an aluminum alloy, copper and a copper alloy.

[0052] The nozzle body and nozzle tip can be thermally connected by at least one thermal interface material. This thermal interface material can be designed to improve heat conduction between the nozzle body and nozzle tip. The thermal interface material can be one of the following, or include one of the following: thermal paste or thermal pad.

[0053] The first connection area of ​​the nozzle body can have at least one magnetic element for attaching the nozzle body to the laser welding head. The magnetic element can be essentially ring-shaped. The first connection area of ​​the nozzle body can have several magnetic elements arranged rotationally symmetrically and / or rotationally symmetrically around the central axis of the nozzle body. The laser welding head can have at least one ferromagnetic element, e.g., a ferromagnetic carrier plate, at its end facing the nozzle, to which the nozzle can be magnetically attached. In other words, a housing of the laser welding head can have at least one ferromagnetic carrier plate at its end facing the nozzle for attaching the nozzle, in particular for attaching the nozzle body, by means of magnetic force. The ferromagnetic carrier plate can be ring-shaped and / or extend around the interior of the nozzle body.of the first connection area.

[0054] The diameter of the nozzle opening can be between 10 mm and 15 mm or between 11 mm and 13 mm, preferably 12.0 mm or 12.2 mm.

[0055] A section of the nozzle body's interior adjacent to the nozzle tip and a section of the nozzle tip's interior adjacent to the nozzle body can have the same diameter. In other words, the nozzle's interior can be essentially stepless between the nozzle body and the nozzle tip. The shape of the nozzle's interior can be designed such that the flow of the shielding gas within the nozzle, from the gas inlet to the nozzle opening and / or at the outlet, is laminar or is designed to be laminar.An offset, in particular an offset perpendicular to the central axis of the nozzle body, between the inside of a section of the wall of the nozzle body adjacent to the interior of the nozzle body and the inside of a section of the wall of the nozzle tip adjacent to the interior of the nozzle tip can be designed in such a way that the laminar flow of the protective gas is not disturbed and / or that no turbulent flow of the protective gas is created.

[0056] The nozzle and / or nozzle body and / or nozzle tip may comprise a substantially conical and / or frustoconical interior. The interior may have an opening angle of 25° to 50° or 30° to 40°. In particular, the interior may have an opening angle symmetrical to the central axis of the nozzle tip of 25° to 50° or 30° to 40°. The central axis of the nozzle tip may correspond to the central axis of the interior.

[0057] A section of the interior of the nozzle tip, adjacent to the nozzle body, can be conical and / or frustoconical, e.g. with an opening angle of 25° to 50° or 30° to 40°, and a section of the interior of the nozzle tip, adjacent to the nozzle opening, can be cylindrical.

[0058] The gas inlet of the nozzle body can be designed to introduce shielding gas into the interior of the nozzle body. The gas inlet can be configured to connect to a gas supply device of the laser welding apparatus for supplying the shielding gas. The velocity of the shielding gas exiting the nozzle opening can range from 17 m / min to 170 m / min.

[0059] The nozzle body and / or nozzle tip may have at least one marking. The nozzle tip may have at least one marking adjacent to the nozzle opening. The marking may indicate the position and / or the path of the central axis of the nozzle tip or nozzle body. In particular, the nozzle tip may have a marking adjacent to the nozzle opening and / or at an end of the nozzle tip that encompasses the nozzle opening to facilitate the adjustment of the nozzle tip or nozzle opening relative to a wire exiting the nozzle opening and / or relative to the laser beam. The marking makes it easier to adjust the nozzle tip relative to the laser beam or relative to the wire.

[0060] The laser welding head can have a ferromagnetic base plate. The nozzle can be attached to the laser welding head by at least one magnetic element located at the first connection point of the nozzle body. The magnetic element can be a magnet or be designed as a magnet. The base plate can be annular and / or include an opening for the passage of the laser beam and / or the wire. The nozzle can be attached to the laser welding head by means of a magnetic coupling.

[0061] The first connection area and the carrier plate can be in contact with each other. The at least one magnetic element or the several magnetic elements can be the sole fastening means between the nozzle, in particular the nozzle body, and the laser welding head.

[0062] A laser welding method according to the present invention can comprise shining the laser beam onto the workpiece and / or shining the laser beam into at least one predetermined processing area. The at least one processing area can define a region on the workpiece into which the laser beam is or is to be shining, melting a material. The material can be the material of the workpiece. "Region on the workpiece" can mean that the processing area is adjacent to the workpiece or that the processing area comprises a part of the workpiece. The laser welding method can further comprise the (simultaneous) feeding of filler material, in particular in the form of the wire described above, into the predetermined processing area. In other words, the fed wire can be or comprise the filler material.In this case, the molten material can be or comprise the deposit material. This allows structures to be formed on the workpiece. A processing area can define an extent, particularly a horizontal extent of a structure. Here, the laser welding process can be, in particular, laser cladding or laser wire cladding. The laser welding process can include the formation of structures on the workpiece. The workpiece material and / or the deposit material can comprise a metal, in particular a metal alloy.

[0063] The laser welding head can be configured to direct the laser beam into at least one predetermined processing area. The laser welding device can further comprise a wire feed device for feeding the wire, in particular for coaxial feeding, into the at least one processing area.

[0064] The laser welding device according to aspects and embodiments of the present disclosure can be configured and / or suitable for carrying out a laser welding method and / or can be used for this purpose. The laser welding method according to aspects and embodiments can be carried out by the laser welding device according to aspects and embodiments. In particular, the laser welding device with the wire feed device can be configured and / or suitable for carrying out a laser wire cladding method and / or can be used for this purpose. The laser wire cladding method can be carried out by the laser welding device with wire feed device. The laser welding device according to aspects and embodiments of the present disclosure can be configured and / or suitable for coaxial laser wire welding or laser wire cladding.

[0065] The nozzle, in particular the nozzle body and nozzle tip, may not contain any optical elements. In other words, the interior of the nozzle may be free of optical elements. The nozzle tip may be the last element of the laser welding device through which the laser beam and / or wire passes before being directed into the processing area. The nozzle body may be the penultimate element of the laser welding device before the nozzle tip through which the laser beam and / or wire passes.

[0066] The distance between the nozzle opening and the machining area can be between 5 mm and 30 mm or between 10 mm and 20 mm. The shielding gas consumption and / or the flow rate of the shielding gas exiting the nozzle opening can be between 2 l / min and 20 l / min. The diameter of the nozzle opening can be between 30% and 80%, preferably 50%, of the diameter of the machining area.

[0067] The processing area can change over time. The processing area should be sealed off from the surrounding air by the protective gas to prevent oxidation. Brief description of the characters

[0068] Aspects and embodiments of the present disclosure are described in detail below with reference to figures. The figures show: Fig. 1 a schematic view of a laser welding device according to embodiments of the present disclosure; Fig. 2 a flowchart of a method for laser welding using a laser welding device system according to embodiments of the present disclosure; Fig. 3 a schematic cross-sectional view of a nozzle for a laser welding device according to embodiments of the present disclosure. Detailed description

[0069] Unless otherwise noted, the same reference numerals are used for identical and equivalent elements in the following text. Redundant descriptions of recurring features are avoided. The various embodiments and features of the figures described below are expressly combinable and should not be understood as complete embodiments.

[0070] Fig. Figure 1 shows a schematic view of a laser welding device according to embodiments of the present disclosure.

[0071] The laser welding device 100 is configured to perform the laser welding process, in particular laser cladding and laser wire cladding, according to aspects and embodiments of the present disclosure. However, the present disclosure is not limited thereto.

[0072] The laser welding device 100 comprises a laser welding head 102 and a nozzle 300. The laser welding device 100 may also include a laser beam device 104, a wire feed device 106, and a control device 108.

[0073] The laser beam device 104 is configured to generate at least one laser beam 10 (processing beam). The laser beam device 104 can include a laser beam source 110. The laser beam source 110 can generate the laser beam 10, which is supplied to the laser welding head 102, for example, via an optical fiber 111. The laser beam device 104 can also include an adjustable collimation optic 112. The collimation optic 112 can also be part of the laser welding head 102.

[0074] The laser welding head 102 is configured to direct the laser beam 10 onto a workpiece 30, and in particular into at least one predefined processing area 32 on the workpiece 30. The laser welding head 102 comprises one or more optical elements 114, 116, 118, 120 for guiding and / or shaping the laser beam 10. The laser welding head 102 can, for example, include lenses, objectives, mirrors, prisms, axicons, etc. The optical elements can be used, for example, to set the focus position and / or focus diameter of the laser beam 10. For example, the laser welding head 102 can include a focusing optic 120 for focusing the laser beam 10 onto a point in the processing area 32. Furthermore, the laser welding head 102 can include optical elements 114, such as axicons and prisms, for generating an annular laser beam 10. The optical elements 114 are arranged in Fig. Figure 1 illustrates a single optical element as an example; however, the present disclosure is not limited to this. Furthermore, the laser welding head 102 can have one or more mirrors 116, 118 for deflecting the laser beam 10.

[0075] "Annular" can also mean that the laser beam 10 has a rotationally symmetric, in particular a rotationally symmetric, shape with respect to the beam propagation direction. According to further embodiments not shown, the laser beam 10 can also be divided into several partial laser beams by means of the laser welding head 104, and these partial laser beams can be directed into the processing area 32. The partial laser beams can be arranged rotationally symmetric and / or rotationally symmetric with respect to each other and with respect to an axis of symmetry, which can be considered a beam axis of the partial laser beams. The laser beam 10 can be annular at least in a section along the wire 20, in particular at and / or after exiting the nozzle 300 and / or before entering the processing area 32.Accordingly, the arrangement of the partial laser beams can be rotationally symmetric and / or rotationally symmetric around the wire 20, at least in one section along the wire 20.

[0076] The wire feed device 106 is configured to feed a wire 20 into the processing area 32. The wire feed device 106 can be arranged on or in the laser welding head 102. In particular, the wire feed device 106 can be rigidly connected to the laser beam device 104 or the laser welding head 102. However, the present disclosure is not limited to this.

[0077] Furthermore, the laser welding device 100 includes the nozzle 300. The nozzle 300 is arranged on the laser welding head 102. The nozzle 300 serves to supply shielding gas 40, as illustrated by arrows in Fig. 1, into the current machining area 32. The machining area 32 is to be sealed off from the ambient air by means of the protective gas in order to prevent oxidation of the material of the workpiece 30 and / or the coating material supplied by the wire 20. The gas 40 is supplied to the nozzle 300 by means of a gas supply device 122, which, for example, comprises a gas reservoir and a pump. The gas supply device 122 is equipped with a gas inlet 304 ( Fig. 3) connected fluidically at the nozzle 300. From the nozzle 300, the gas 40 is guided towards the workpiece 30 or the machining area 32, and then exits from a nozzle opening on the underside (in Fig. 1 not shown).

[0078] The nozzle 300 serves to create a laminar flow of the gas 40. The nozzle 300 is designed in two parts and will be described in detail with reference to the following figures. Furthermore, the laser beam 10 and the wire 20 pass through the nozzle 300 before exiting the nozzle opening. Subsequently, the laser beam 10 and the wire 20 enter the processing area 32. The laminar flow of the gas 40 created by the nozzle 300 can be substantially rotationally symmetric about an axis of symmetry, particularly at the nozzle opening.

[0079] In coaxial laser welding, the laser beam 10 and the fed wire 20 should be as coaxial as possible after exiting the laser welding device 100, particularly after exiting the nozzle 300, and especially upon entering the processing area 32. The laser beam 10 can be adjusted for this purpose. In particular, the laser beam 10 can be adjusted in a plane perpendicular to its beam propagation direction, for example by adjusting a coupling 115 for connecting the optical fiber 111 to the laser welding head 102.

[0080] In Fig. Figure 1 illustrates the adjustment by the double arrow 51. Furthermore, the wire 20 can be adjusted. In particular, the wire 20 can be adjusted in a plane perpendicular to a longitudinal axis of the wire 20 or perpendicular to the direction of propagation of the laser beam 10 in at least one section of the laser beam 10, for example, in the interior of the nozzle 300. Fig. Figure 1 illustrates the adjustment of the wire 20 by the double arrow 52. The two-part nozzle 300 comprises a nozzle body and a nozzle tip with the nozzle opening. The nozzle tip and the nozzle body can be adjusted relative to each other, in particular in a plane perpendicular to the central axis of the nozzle body. This allows the nozzle opening to be adjusted relative to the beam propagation direction of the laser beam 10 or the axis of the wire 20 at its exit point from the nozzle opening.

[0081] This, in turn, allows the flow of gas 40 to be adjusted separately. The flow of gas 40 can thus be set coaxially to the laser beam 10 or to the wire 20. In particular, the axis of symmetry of the gas flow can be set coaxially to the beam path of the laser beam 10 or to the longitudinal axis of the wire 20. Therefore, a coaxial shielding gas supply for a laser welding process can be achieved using the nozzle 300. Fig. Figure 1 illustrates the adjustment of the nozzle tip by the double arrow 53.

[0082] The control device 108 is configured to control elements of the laser welding device 100, for example the laser welding head 102, the laser beam device 104, the wire feed device 106, and the gas feed device 122, in order to carry out a laser welding process according to embodiments and aspects of the present disclosure.

[0083] Using the laser welding device 100, structures 34, in particular cylindrical structures 34 or a weld seam, can be formed on the surface of the workpiece 30. A predefined processing area 32 can correspond to a structure 34 to be formed.

[0084] Fig. Figure 2 shows a flowchart of a method for laser welding using a laser welding device 100 according to embodiments of the present disclosure. The method can be carried out using the laser welding device 100 according to Fig. 1 will be carried out.

[0085] Method 200 comprises a first step 201 in which the laser welding head of the laser welding device projects a laser beam into a predetermined processing area on a workpiece. Method 200 comprises a second step 202 in which the wire feed device of the laser welding device feeds a wire-shaped deposit material into the predetermined processing area. Method 200 comprises a third step 203 in which the gas supply device of the laser welding device supplies shielding gas into the processing area via the nozzle. The flow of the shielding gas at the exit of the nozzle and / or at the entry into the processing area and / or into an area around the processing area, particularly on the surface of the workpiece 30, is laminar. Steps 201-203 can be performed in parallel.

[0086] Fig. Figure 3 shows a schematic cross-sectional view of a nozzle for a laser welding device according to embodiments of the present disclosure.

[0087] The nozzle 300 comprises a nozzle body 302 with a gas inlet 304 for supplying the shielding gas 40 and a nozzle tip 306 with a nozzle opening 308 for expelling the shielding gas 40 from the nozzle 300. The nozzle body 302 includes a first connection area 310 for attaching the nozzle body 302, and thus the nozzle 300 as a whole, to the laser welding head 102, and a second connection area 312. The nozzle tip 306 has a third connection area 314. The second connection area 312 of the nozzle body 302 and the third connection area 314 of the nozzle tip 306 are inserted into one another. More precisely, the second connection area 312 is inserted into the third connection area 314 and the third connection area 314 surrounds the second connection area 312 in a radial direction or perpendicular to a central axis 303 of the nozzle body 302.

[0088] The first connection area 310 is formed on a first, upper end section of the wall 321 of the nozzle body 302 and extends radially outwards from it. As shown, the first connection area 310 is annular or flange-shaped. The second connection area 312 is formed on a second, lower end section of the wall 321 of the nozzle body 302. The second connection area 312 is formed as a stepped offset and / or recess on the outside of the wall 321. The third connection area 314 is formed on a first, upper end section of the wall 323 of the nozzle tip 306. The third connection area 314 is formed as a stepped offset and / or recess on the inside of the wall 323 of the nozzle tip 306. The second connection area 312 and the third connection area 314 are each annular, as shown.The nozzle opening 308 is formed on a second, lower end section of the wall 323 of the nozzle tip 306. The center point of the nozzle opening 308 can lie on a central axis 307 of the nozzle tip 306.

[0089] The nozzle body 302 comprises an interior 320. The nozzle tip 306 comprises an interior 322. The gas inlet 304 serves to introduce the gas 40 into the interior 320 of the nozzle body 302. The gas inlet 304 is designed as a through-hole or channel in a section of the wall 321 of the nozzle body 302 adjacent to the interior 320.

[0090] If the interior 320 of the nozzle body 302 is substantially rotationally symmetric, the central axis 303 of the nozzle body 302 can be defined as the axis of symmetry of the nozzle body 302. The central axis 303 of the nozzle body 302 can form the central axis of the nozzle 300. The nozzle tip 306 also has a central axis 307. If the interior 322 of the nozzle tip 306 is substantially rotationally symmetric, the central axis 307 of the nozzle tip can be defined as the axis of symmetry of the nozzle tip 306. The central axis 307 can pass through the center point of the nozzle opening 308, which is also substantially rotationally symmetric.

[0091] The nozzle 300 can be easily attached to and removed from the laser welding head 102 via the first connection area 310. The attachment of the nozzle 300 to the laser welding head 102 can be achieved using a magnetic coupling. For example, the first connection area 310 can have at least one magnetic element 311a,b, and the laser welding head 102 can have a ferromagnetic carrier plate 103. Fig. Figure 3 shows two magnetic elements 311a,b. The magnetic elements 311a,b can be bonded into a material of the first connection area 310. The magnetic elements 311, 311b can be arranged rotationally symmetrically around the central axis of the nozzle body 302. This allows the nozzle 300 to be attached to and removed from the laser welding head 102 without additional elements or tools. Therefore, the nozzle body 302 and the nozzle 300 as a whole are easily interchangeable.

[0092] In Fig. Not shown are the laser beam 10 and the wire 20. However, these can essentially run coaxially with the central axis of the nozzle body 302 or can be adjusted coaxially to the central axis of the nozzle body 302.

[0093] The second connection area 312 of the nozzle body 302 and the third connection area 314 of the nozzle tip 306 are fastened to each other by means of four screw elements. In the cross-sectional view of the Fig. Figure 3 shows only two screw elements 318a,b, which are opposite each other with respect to the central axis 307 of the nozzle tip 306. Not shown are two further screw elements, which are also opposite each other, but which are arranged around the central axis 307 at an angle of 90° to the screw elements 318a,b. The four screw elements can, for example, be designed as set screws.

[0094] The third connection area 314 has through holes (without reference numerals) with internal threads corresponding to the screw elements. One of the screw elements passes through each of these holes and rests with its end on the second connection area 312. The second connection area 312 can therefore be clamped into the third connection area 314, so that the nozzle tip 306 and the nozzle body 302 are fastened together. By unscrewing the screw elements sufficiently, the fastening can be released, allowing the nozzle tip 306 to be easily removed from the nozzle body 302. Therefore, the nozzle tip 306 is easily replaceable. Threads on the nozzle tip 306 and the nozzle body 302 are not required.

[0095] Furthermore, the screw elements allow the nozzle tip 306 to be adjustable or displaceable relative to the nozzle body 302 in a plane perpendicular to the central axis 303 of the nozzle body 302. Thus, the screw elements can be screwed in or out such that their ends continue to rest on the second connection area 312 and the nozzle tip 306 and the nozzle body 302 remain attached to each other, but that the central axis 307 of the nozzle tip 306 and the central axis 303 of the nozzle body 302 are displaced relative to each other, as shown in Fig. Figure 3 illustrates this. This adjustability allows the nozzle opening 308 to be positioned relative to the direction of propagation of the laser beam 10 or the axis of the wire 20 at its exit from the nozzle opening. This, in turn, allows the gas flow 40 to be adjusted coaxially with the laser beam 10 or the wire 20. Specifically, the axis of symmetry of the gas flow 40 can be adjusted coaxially with the beam path of the laser beam 10 or the longitudinal axis of the wire 20. Thus, the coaxial supply of the shielding gas can be achieved by means of the two-part nozzle 300.

[0096] One of each pair of opposing screw elements can be replaced by a spring element. For example, among the screw elements 318a,b, one of the two screw elements, i.e., 318a or 318b, can be replaced by a spring element. The spring element is arranged in the gap between the second connection area 312 and the third connection area 314 such that it provides an elastic restoring force towards the center of the nozzle body 302, more precisely towards the central axis 303 of the nozzle body 302.

[0097] To allow sufficient adjustability, the inner diameter of the third connection area 314 is larger than the outer diameter of the second connection area 312. In other words, there is a gap, which may be annular, between the third connection area 314 and the second connection area 312 in a plane perpendicular to the central axis 303 of the nozzle body 302.

[0098] A thermal conductor, for example a thermal paste, can be arranged between the surfaces of the second connection area 312 and the third connection area 314, in particular between horizontally arranged surfaces thereof, to improve thermal coupling between the nozzle body 302 and the nozzle tip 306. The nozzle body 302 can, for example, be made of aluminum or an aluminum alloy, and the nozzle tip 306 can be made of copper.

[0099] The flow of gas 40 formed by means of the nozzle 300 is laminar. In particular, the flow of gas 40 can be laminar at the exit from the nozzle opening 308, at the entry into the machining area 32 and / or in the area around the machining area 32, especially on the surface of the workpiece 30.

[0100] The interior 320 of the nozzle body 302 is essentially conical. The interior 322 of the nozzle tip 306 has an upper section adjacent to the interior 320 and a lower section adjacent to the upper section. The upper section is essentially conical. The lower section is cylindrical. A transition area may be arranged between them. Together, the interior 320 and the interior 322 form the interior of the nozzle 300. The in Fig. The offset shown in Figure 3 between an inner side of the section of wall 321 adjoining the interior 320 and an inner side of the section of wall 323 adjoining the interior 322 can occur when adjusting the nozzle tip 306 by means of the screw elements 318a,b. This offset is sufficiently small that the laminar flow of the protective gas 40 is not disturbed.

[0101] In Fig. Figure 3 shows a fully formed structure 34a and a structure 34b that is currently being formed. The structure 34b is formed in the (current) machining area 32. A distance a between the nozzle 300 or the nozzle opening 308 and the machining area 32 can be defined as the distance between the nozzle opening 308 and a top surface of the currently formed structure 34b, or, if the formation of the structure 34b in the machining area 32 is in its initial stages, as the distance between the nozzle opening 308 and the top surface of the workpiece 30.

[0102] The in Fig.The nozzle 300 shown in Figure 3 further comprises a cooling device 324. The cooling device serves to actively cool the nozzle 300 by means of a cooling medium. The cooling device 324 is arranged on an outer surface of the wall 321 of the nozzle body 302. The cooling device 324 can, for example, be designed as a block with one or more channels for the cooling medium. The cooling device 324 can, as shown, have cooling medium connections 325a,b for connection to a cooling medium circuit. Alternatively, the cooling device 324 can be designed for passive cooling of the nozzle 300.

[0103] According to embodiments not shown, the nozzle 300 can also have three screw elements, each arranged around the central axis 307 at an angle of 120° to each other. Thus, there is a 120° angle between each pair of screw elements. In this case, one of the three screw elements can be replaced by a spring element.

Images