Method for laser wire welding and laser wire welding system

Abstract

The invention relates to a method for laser wire welding by means of a laser wire welding system, comprising the following steps: actuating a wire feed device of the laser wire welding system for changing the wire feed, actuating a laser beam device of the laser wire welding system for changing the laser beam, the wire feed device is controlled in order to start the wire feed and the laser beam device is controlled in order to start the laser beam, taking into account a delay time of the laser beam device and / or a delay time of the wire feed device, such that a change time point of the wire feed and a change time point of the laser beam have a predetermined time interval from each other. Furthermore, a laser wire welding system configured to perform the method is described.

Description

Technical Field

[0001] The present invention relates to a method for laser wire welding, particularly a method for laser wire surfacing, and a laser wire welding system, particularly a laser wire surfacing system. Background Technology

[0002] Laser wire welding, especially laser wire cladding, or simply laser welding, is an additive manufacturing method in which a laser beam melts a filamentary (welding) material and bonds it to at least one workpiece (also called a substrate). Multiple workpieces can be welded together using this material. Here, the laser welding head irradiates the processing area on the workpiece with a laser beam from a laser source or the end of a laser fiber. A wire feed device transports the wire (also called welding wire) to the processing area. The wire feed device can be arranged on or within the laser processing head, or as part of it.

[0003] Figures 5a-5c The possible position of the wire tip 2a relative to the laser beam focus 10a during laser wire welding is shown. Figure 5a In this configuration, the wire tip is positioned at the focal point of the laser beam. Various problems can arise if the control of the laser beam power and the feed control of the wire or wire tip are not sufficiently synchronized or coordinated. For example, if the wire is advanced too early or the laser beam power is increased too late, the wire tip will be positioned above or before the focal point of the laser beam (in the laser beam). Figure 5c (As shown in the diagram). What may occur here is that the tip of the wire does not melt sufficiently, which could result in inadequate bonding between the wire and the workpiece. Conversely, if the wire is advanced too late or the laser beam is turned on too early, the wire tip will be below or behind the focal point of the laser beam (in...). Figure 5b (As shown in the diagram). What may happen here is that the wire melts prematurely and moves upward or away from the workpiece as a droplet. In addition to the aforementioned poor connection, this may also lead to damage to the wire guide nozzle of the wire feed equipment (so-called "balling"). If the workpiece is relatively thin, a lack of synchronization or poor timing coordination between laser beam power control and wire feed may further lead to excessive heat input to the workpiece material.

[0004] These issues are particularly important when only small and / or discrete structures should be applied to the workpiece, such as cylinders with a diameter of 1 mm to 5 mm and a height of 2 mm to 10 mm, because welding errors are very large relative to the overall structure. Summary of the Invention

[0005] One objective of this invention is to describe an improved method for laser wire welding, and more particularly an improved method for laser wire surfacing.

[0006] Another objective of this invention is to describe a method for laser wire welding that can prevent or at least reduce welding errors caused by insufficient or lack of synchronization or time coordination between the control of wire feeding and the control of the laser beam.

[0007] Another objective of the present invention is to describe a method for laser wire welding in which changes in wire feeding, particularly initiation and / or cessation, and changes in the laser beam, particularly initiation and / or closure, can be coordinated in time, i.e. performed at precise time intervals, particularly synchronously.

[0008] Another objective of this invention is to describe a method for laser wire welding in which the position of the welding wire tip can be determined simply, quickly and accurately.

[0009] Another objective of the present invention is to describe a laser wire welding system configured to perform the laser wire welding method.

[0010] Other tasks, technical advantages, and effects will be derived by those skilled in the art from the study description, drawings, and implementation methods.

[0011] Within the scope of this invention, "change of laser beam" refers to a change in the laser beam configuration, such as a change in laser beam power and / or a change in the laser beam focal position. A change in laser beam power can include increasing the laser beam power, particularly raising the laser beam power from a current value below a predetermined value to a predetermined value, and / or decreasing the laser beam power, particularly lowering the laser beam power from a current value above a predetermined value to a predetermined value. The predetermined value and / or the current value can be greater than or equal to 0 watts. "Turn on the laser beam" means increasing the laser beam power from 0 watts to a predetermined value greater than 0 watts. "Turn off the laser beam" means decreasing the laser beam power from a value greater than 0 watts to 0 watts. Therefore, a change in the laser beam or laser beam power includes turning the laser beam on and off. A change in the laser beam can also include a change in the laser beam focal position along the propagation direction.

[0012] Within the scope of this invention, "change in wire feeding" refers to a change in wire feeding settings, such as a change in wire feeding speed and / or a change in wire feeding direction. "Starting wire feeding" can include increasing the wire feeding speed from 0 m / s to a predetermined amount greater than 0 m / s, for example, between 15 mm / s and 120 mm / s. "Stopping wire feeding" refers to decreasing the wire feeding speed from an amount greater than 0 m / s to 0 m / s. Changes in wire feeding speed can particularly include increasing the wire feeding speed from a current value below a predetermined value to a predetermined value, or decreasing the wire feeding speed from a current value above a predetermined value to a predetermined value. The predetermined value and / or the current value can be greater than or equal to 0 m / s. Therefore, changes in wire feeding can include starting and / or stopping wire feeding. Wire feeding can include wire delivery, i.e., entering or exiting the processing area from the wire feeding device. A wire feeding speed greater than 0 m / s can be referred to as wire feeding to a predetermined processing area of ​​the workpiece. A wire conveying speed of less than 0 m / s can be referred to as pulling back or removing the wire from the processing area on the workpiece.

[0013] Therefore, changes in yarn conveying can include not only changes in yarn conveying speed, i.e., changes in the magnitude of yarn conveying speed, but also changes in the sign of yarn conveying speed, i.e., changes in yarn conveying direction (reversal of yarn conveying). A change in yarn conveying direction means changing the yarn conveying speed from a value equal to or greater than 0 m / s to a negative value or changing the yarn conveying speed from a negative value to a value equal to or greater than 0 m / s.

[0014] The position of a filament can be defined as the location of its end in a three-dimensional, especially Cartesian, coordinate system. The position of a filament can be given or defined, for example, relative to the TCP ("tool center point"), or about the world coordinate system.

[0015] The "timing point of the filament transport control" or "timing point of the laser beam control" can refer to the time when the filament transport device receives a corresponding control signal from the control device to change the filament transport, or the time when the laser beam device receives a control signal from the control device to change the laser beam, for example, via a bus or bus system or wirelessly. This can also be referred to as "applying" a control signal to the filament transport device or the laser beam device. In the case of real-time control, the timing point of the filament transport control or the laser beam control can substantially correspond to the time when the control device sends a control signal to the filament transport device to change the filament transport or sends a control signal to the laser beam device to change the laser beam. The (actual) "laser beam change timing point" or the (actual) "filament transport change timing point" can refer to the time when the change in the laser beam or filament transport actually occurs or is completed. The (actual) laser beam activation timing point can be defined as the time when the laser beam reaches a predetermined laser beam power. The (actual) filament transport start-up timing point can be defined as the time when the filament transport reaches a predetermined filament transport speed.

[0016] The delay time of a laser beam device can be defined as the time interval from receiving a control signal to change the laser beam to the completion of that change, i.e., reaching the desired laser setting. Similarly, the delay time of a wire conveying device can be defined as the time interval from receiving a control signal to change the wire conveying, i.e., the completion of that change, i.e., reaching the desired wire conveying setting.

[0017] This invention is based on the understanding that in laser wire welding, there is a time delay between the application of a control signal to the wire feeding device or laser beam device and the actual change time of the wire feeding or laser beam.

[0018] The core of this invention is to take into account these delay times when manipulating the wire feeding device to change the wire feed (e.g., starting the wire feed) and manipulating the laser beam device to change the laser beam (e.g., turning on the laser beam), so that the changes in wire feed and laser beam are performed at predetermined time intervals, for example, synchronously. This ensures optimal welding results.

[0019] According to one aspect of the present invention, a method for laser wire welding using a laser wire welding system is described. The method includes the following steps: manipulating a wire feeding device of the laser wire welding system to change the wire feeding (especially starting the wire feeding, stopping the wire feeding, changing the wire feeding speed, and / or changing the wire feeding direction); and manipulating a laser beam device of the laser wire welding system to change the laser beam (especially turning on the laser beam, turning off the laser beam, changing the laser beam power, and / or changing the focal position of the laser beam). The wire feeding device and the laser beam device are manipulated in such a way that the timing of the change in wire feeding and the timing of the change in laser beam have a predetermined time interval between them. Here, the timing of the wire feeding manipulation and the timing of the laser beam manipulation can be determined or coordinated such that the timing of the change in wire feeding and the timing of the change in laser beam have a predetermined time interval between them or are within a predetermined time interval.

[0020] According to another aspect of the present invention, a method for laser wire welding using a laser wire welding system is described, the method comprising the steps of: manipulating a wire feeding device of the laser wire welding system to initiate wire feeding (e.g., from a predetermined start position of the wire), and manipulating a laser beam device of the laser wire welding system to turn on a laser beam for melting the wire, wherein the wire feeding device is manipulated to initiate wire feeding and the laser beam device is manipulated to turn on the laser beam, taking into account the delay time of the laser beam device and / or the delay time of the wire feeding device, such that the start time of the wire feeding and the turn-on time of the laser beam have a predetermined first time interval between them.

[0021] According to another aspect of the present invention, a method for laser wire welding using a laser wire welding system is described, the method comprising the steps of: manipulating a wire feeding device of the laser wire welding system to initiate wire feeding (e.g., from a predetermined starting position of the wire), and manipulating a laser beam device of the laser wire welding system to turn on at least one laser beam for melting the wire, wherein the timing of the wire feeding manipulation and the timing of the laser beam manipulation are determined or coordinated such that the starting time of the wire feeding and the turning time of the laser beam have a predetermined (first) time interval between them or are within a predetermined (first) time interval between them.

[0022] According to another aspect of the present invention, a method for laser wire welding using a laser wire welding system is described, the method comprising the steps of: manipulating a wire feeding device of the laser wire welding system to stop wire feeding, and manipulating a laser beam device of the laser wire welding system to turn off the laser beam, wherein the timing of the wire feeding control of the wire feeding device to stop wire feeding and the timing of the laser beam control of the laser beam device to turn off the laser beam are determined or coordinated with each other such that the stopping time of the wire feeding and the turning off time of the laser beam have a predetermined (second) time interval between them or are within a predetermined (second) time interval between them.

[0023] According to another aspect of the present invention, a laser wire welding system is described, comprising: a laser beam device configured to generate a laser beam and / or irradiate a pre-given processing area with the laser beam; a wire conveying device configured to convey a wire to the pre-given processing area; and a control device, particularly a real-time control device, configured to manipulate the laser beam device and the wire conveying device, wherein the laser wire welding system is configured to perform a method according to one aspect or embodiment disclosed herein. The control device may be configured to manipulate elements of the laser wire welding system to perform a method according to one aspect or embodiment disclosed herein. The laser wire welding system may further include a bus or bus system to which the control device, the wire conveying device, and / or the laser beam device are connected, or the control device is connected to the wire conveying device and / or the laser beam device via the bus or bus system.

[0024] Aspects and embodiments of the present invention may include one or more of the following optional features: The wire feeding device can be controlled by the control equipment of the laser wire welding system. The control equipment can be a real-time control device. The control equipment can have a delay time of less than 5 ms, for example, 1 ms. The control equipment can be connected to the wire feeding device and / or the laser beam device via a bus or bus system. The bus or bus system can be a real-time bus or real-time bus system. The bus or bus system can have a delay time of less than 5 ms, for example, 1 ms.

[0025] The pre-defined time interval (e.g., the first and / or the second) can be greater than or equal to 0 ms. If the pre-defined time interval is equal to 0 ms, the timing of the filament feed control and the timing of the laser beam control are simultaneous, that is, the laser beam control and the filament feed control are performed synchronously.

[0026] The start time of the wire feed and the turn-on time of the laser beam can be the same or simultaneous. In other words, the start of the wire feed and the turn-on of the laser beam can occur simultaneously or synchronously. Similarly, the stop time of the wire feed and the turn-off time of the laser beam can be the same or simultaneous. In other words, the stop of the wire feed and the turn-off of the laser beam can occur simultaneously or synchronously. The change time of the wire feed and the change time of the laser beam can be the same or simultaneous. In other words, the change of the wire feed and the change of the laser beam can occur simultaneously or synchronously.

[0027] The timing of the filament feed control can be determined taking into account the delay time of the filament feed equipment. The timing of the laser beam control can be determined taking into account the delay time of the laser beam equipment. The timing of the filament feed control and the timing of the laser beam control can be coordinated with each other, taking into account the delay time of the filament feed equipment and / or the delay time of the laser beam equipment.

[0028] The delay time of the filament feeder can be an experimentally determined delay time or can be based on the manufacturer's specifications. The delay time of the laser beam device can be an experimentally determined delay time or can be based on the manufacturer's specifications. The delay time of the filament feeder can be greater than the delay time of the laser beam device.

[0029] The method may include determining the delay time of the laser beam device and / or the delay time of the wire feed device. Alternatively, the delay time of the laser beam device and / or the delay time of the wire feed device may be predetermined, for example, as specified by the manufacturer. The method may include storing the delay time of the laser beam device and / or storing the delay time of the wire feed device, for example, in the control equipment of a laser wire welding system.

[0030] The delay time of a laser beam device can refer to or include the duration between the time point at which the control signal for changing the laser beam (the change control signal) is received from the laser beam device control equipment and the (actual) change time of the laser beam.

[0031] The delay time of a laser beam device can include an on-delay time. The on-delay time refers to the duration between the point in time when the laser beam device receives the control signal (on-delay control signal) for turning on the laser beam from the control device and the (actual) on-delay time of the laser beam. In other words, the on-delay time of a laser beam device can be defined as the duration between the point in time when laser beam manipulation for turning on the laser beam occurs and the (actual) on-delay time of the laser beam. The delay time of a laser beam device can also include a off-delay time. The off-delay time refers to the duration between the point in time when the laser beam device receives the control signal (off-delay control signal) for turning off the laser beam from the control device and the (actual) off-delay time of the laser beam. In other words, the off-delay time of a laser beam device can be defined as the duration between the point in time when laser beam manipulation for turning off the laser beam occurs and the (actual) off-delay time of the laser beam. The on-delay time and off-delay time of a laser beam device can be the same or different from each other.

[0032] The delay time of a filament conveying device can refer to the duration between the time when the control signal for changing the filament conveying is received from the filament conveying device control equipment and the actual time when the filament conveying is changed.

[0033] The delay time of a yarn conveying device can include a start-up delay time. The start-up delay time can refer to the duration between the time the yarn conveying device receives the control signal for starting the yarn conveying from the control device and the (actual) start time of the yarn conveying. In other words, the start-up delay time of the yarn conveying device can be defined as the duration between the time of the yarn conveying control for starting the yarn conveying and the (actual) start time of the yarn conveying. The delay time of yarn conveying can include a stop-up delay time. The stop-up delay time of the yarn conveying device can refer to the duration between the time the yarn conveying device receives the control signal for starting the yarn conveying from the control device and the actual stop time of the yarn conveying. In other words, the stop-up delay time of the yarn conveying device can be defined as the duration between the time of the yarn conveying control for stopping the yarn conveying and the (actual) stop time of the yarn conveying. The start-up delay time and the stop-up delay time of the yarn conveying device can be the same or different from each other. Accordingly, the increase and decrease (or speed magnitude) of speed can be applied to the speed change delay time and / or the direction change delay time.

[0034] The timing for controlling the laser beam to turn on can be determined taking into account the turn-on delay time of the laser beam device. The timing for controlling the laser beam to turn off can be determined taking into account the turn-off delay time of the laser beam device.

[0035] The timing for initiating the silk conveying operation can be determined taking into account the start-up delay time of the silk conveying equipment. The timing for stopping the silk conveying operation can be determined taking into account the stop delay time of the silk conveying.

[0036] The timing of the silk conveying control for changing the silk conveying speed can be determined taking into account the speed change delay time of the silk conveying equipment. Similarly, the timing of the silk conveying control for changing the silk conveying direction can be determined taking into account the direction change delay time of the silk conveying equipment.

[0037] The timing of wire feed control and / or laser beam control can also be determined taking into account the delay time of the control equipment. The delay time of the control equipment may include the processing delay time of the control equipment. Alternatively or additionally, the delay time of the control equipment may include the delay time of the bus or bus system of the laser wire welding system, particularly the delay time of the bus or bus system between the control equipment and the wire feed equipment and / or between the control equipment and the laser beam equipment. The delay time of the bus or bus system may be 1 ms or less.

[0038] Laser beam devices can be configured to change the laser beam, particularly to turn the laser beam on and / or off and / or change the laser power. Wire conveying devices can be configured to change wire conveying, particularly to start wire conveying, stop wire conveying, change wire conveying speed, and / or change wire conveying direction.

[0039] The control equipment can be a real-time control device. The wire feeding equipment and / or laser beam equipment can be operated in real time via the control equipment. This operation can be performed through the bus or bus system of the laser wire welding system.

[0040] The bus system may be a fieldbus system or may include fieldbus systems. The bus system may be a bus system selected from the following group or may include bus systems selected from the following group: Ethercat®, Profinet®, Ethernet-IP®.

[0041] The method may further include the following steps: advancing the wire from an unknown position using a wire feeder; determining the contact time point at which the wire contacts the object, particularly the workpiece; and determining the position of the wire at the contact time point, particularly the position of the wire tip, as the wire's ausgangsposition. The wire's ausgangsposition can be determined relative to the tool center point (TCP) of the laser wire welding system. These steps can be performed before initiating wire feed or before actual laser wire welding. This allows for a simple, fast, reliable, and accurate determination of the wire's ausgangsposition.

[0042] Determining the contact time point can include detecting or probing an electrical signal. This signal can be generated when the wire, especially the wire tip, touches an object or workpiece. Determining the contact time point can also include detecting the force required for wire feeding. Alternatively or additionally, determining the wire position as the starting position of the wire can preferably be done using the camera unit of the laser wire welding system.

[0043] The determined starting position can be compared with a pre-defined starting position. If the determined starting position matches the pre-defined starting position, the determined starting position can be determined as or used as the pre-defined starting position. Alternatively, starting from the determined starting position, the thread can be retracted or advanced by a defined length to bring it to the pre-defined starting position. The defined length can be derived from a comparison or difference between the determined starting position and the pre-defined starting position.

[0044] Laser cladding or laser wire cladding can be coaxial laser cladding or laser wire cladding. At least one laser beam can extend coaxially with the wire along at least one segment of the wire. At least one laser beam can, particularly in a plane perpendicular to the wire, be configured as a ring. This plane can preferably be arranged in a segment of the wire, along which at least one laser beam extends coaxially with the wire. At least one laser beam can have a rotationally symmetric and / or rotationally symmetric shape, particularly in a designated plane perpendicular to the wire. The plane perpendicular to the wire and / or the segment of the wire can be arranged in a pre-defined processing area.

[0045] The method may include generating a laser beam and irradiating the laser beam into a pre-defined processing area. The method may include feeding a filament into the pre-defined processing area. According to an embodiment, the method may include irradiating one or more laser beams into the pre-defined processing area. The one or more laser beams may be fed axially. The plurality of laser beams may be arranged rotationally symmetrically and / or rotationally symmetrically with respect to each other, and preferably rotationally symmetrically and / or rotationally symmetrically with respect to the filament.

[0046] This method may include generating and / or irradiating a continuous laser beam. This method may include continuously feeding a filament. The term "continuous" here may be understood as "time-constant" or as the opposite of "pulsed."

[0047] The laser beam can be a pulsed laser beam. The method can include generating and / or irradiating the pulsed laser beam. Therefore, the method can include repeatedly turning the laser beam on and off.

[0048] The method may include pulsed or pulsed wire feeding. Therefore, the method may include repeatedly starting and stopping the wire feeding. With each start and stop of the wire feeding, the laser beam may be turned on and off. The start and stop of the wire feeding and the on and off of the laser beam may be coordinated in time such that the start time of the wire feeding and the on time of the laser beam have a predetermined first time interval relative to each other, and / or such that the stop time of the wire feeding and the off time of the laser beam have a predetermined second time interval relative to each other. The predetermined first time interval and the predetermined second time interval may be the same or different from each other.

[0049] This method may include alternately or repeatedly advancing and retracting the yarn. Here, the retraction distance may be less than the distance the yarn was advanced in the previous step.

[0050] The method for laser wire welding can be a method for laser wire surfacing. The method according to the aspects and embodiments can be used for laser wire surfacing and / or laser wire brazing. The system according to the aspects and embodiments can be used for laser wire surfacing and / or laser wire brazing. The method can be used for laser wire welding and / or laser wire brazing of metal workpieces and / or metal wires. The system can be configured for laser wire welding and / or laser wire brazing of metal workpieces and / or metal wires.

[0051] This method can be used for laser surfacing to apply material from a wire to a workpiece. The wire and / or workpiece may have or be composed of materials including at least one of the following: titanium (Ti), aluminum (Al), TiAl, titanium alloys, and aluminum alloys, especially 5000 series, 6000 series, or 7000 series aluminum alloys.

[0052] This method can be used for 3D printing and / or for progressively applying material from a filament to a workpiece. Progressive application may include multiple on and off cycles of the laser beam, and correspondingly multiple starts and stops of the filament feed. The step duration can be defined as the duration between the on and off cycles of the laser beam or between the start and stop cycles of the filament feed. Alternatively, the step duration can be defined as the duration between two on cycles of the laser beam or between two start cycles of the filament feed. In this case, the step duration may also include the duration of cooling, such as the cooling of the applied material. The step duration can be between 100 ms and 2 s, preferably between 300 ms and 500 ms, and particularly preferably 400 ms. These limits are included separately.

[0053] This method can alternatively or additionally be used to apply structures, particularly cylindrical structures, to a workpiece, for example, having a diameter of 1 mm to 5 mm, preferably 3 mm, and / or a height between 2 mm and 10 mm, preferably between 5 mm and 10 mm, particularly preferably 6 mm, or between 5 mm and 15 mm, preferably 10 mm. This method can also alternatively or additionally be used to apply structures to a workpiece having a wall thickness between 1 mm and 3 mm, preferably 2 mm, and a height between 2 mm and 10 mm, preferably between 5 mm and 10 mm, particularly preferably 6 mm, or between 5 mm and 15 mm, preferably 10 mm. The limits are included respectively.

[0054] A predefined machining area can be specified as a range within which the material at the wire tip should be melted by the laser beam. The predefined machining area can be positioned on and / or above the workpiece surface. The predefined machining area can vary over time. The machining area can correspond to the tool center point. The system can also be called an apparatus. The control equipment can also be called apparatus control. The workpiece can also be called a substrate.

[0055] The laser beam device may include a laser source and / or a laser welding head. A wire feed device may be arranged on or within the laser processing head. In particular, the wire feed device may be fixedly connected to the laser beam device or the laser processing head.

[0056] The change in the laser beam can occur before or after the change in the filament transport. The changes can also occur simultaneously. The first time interval and / or the second time interval can be of equal magnitude. The time intervals, such as the first and / or second time intervals, can be between 0 ms and 10 ms, preferably between 0 ms and 5 ms, and particularly preferably between 0 ms and 1 ms. If the time intervals, such as the first and / or second time intervals, are between 0 ms and 1 ms, then the laser beam and the filament transport can be referred to as "synchronized".

[0057] The thickness of the filament can be between 0.5 mm and 2 mm, preferably between 0.8 mm and 1 mm, the limits of which are included. Attached Figure Description

[0058] The aspects and embodiments of the present invention are described in detail below with reference to the accompanying drawings. The drawings illustrate: Figure 1 A schematic diagram of a laser wire welding system according to an embodiment of the present invention is shown; Figure 2 A flowchart is shown illustrating a method for laser wire welding using a laser wire welding system according to an embodiment of the present invention; Figure 3 A flowchart illustrating a method for determining a delay time according to an embodiment of the present invention; Figure 4ac shows a flowchart of a method for determining the starting position of a filament according to an embodiment of the present invention; Figure 5a -c indicates the position of the wire tip relative to the focal point of the laser beam. Detailed Implementation

[0059] In the following text, unless otherwise stated, the same reference numerals are used for identical and equivalent elements. Redundant descriptions of repetitive features are avoided. The various embodiments and features described in the accompanying drawings are clearly combinable and should not be construed as closed embodiments.

[0060] The directions x, y, and z shown in the diagram are the coordinate axes of a Cartesian coordinate system. The direction along the z-axis can be called the vertical direction, and the directions along the x or y-axis can be called the horizontal direction.

[0061] Figure 1 A schematic diagram of a laser wire welding system according to an embodiment of the present invention is shown.

[0062] The laser wire welding system 100 is configured to perform a method for laser wire brazing or laser wire welding, particularly laser wire surfacing, according to aspects and embodiments of the present invention. However, the invention is not limited thereto.

[0063] The laser wire welding system 100 includes a laser beam device 106, a wire transport device 102, and a control device 105. The laser wire welding system 100 may include a laser processing head 101, particularly a laser welding head, in which optical elements for guiding and / or shaping the laser beam are arranged. The laser beam device 106 may be or include a laser source 103. The laser beam device 106 may further include an adjustable collimating optics device 110. The laser source 103 can be used to generate at least one laser beam 10. The laser source 103 can generate a laser beam 10 (processing beam), which is transported to the laser processing head 101, for example, via an optical fiber 310.

[0064] In laser wire welding or brazing, the welding material, in the form of welding wire 2 (hereinafter referred to as wire), is fed to the workpiece 3 or the processing area 31 using a wire feeding device 102. A laser beam 10 is generated by a laser beam device 106 and irradiates the processing area 31. As a result, the material of the fed wire melts and bonds with the material of the workpiece 3. Wire guidance proceeds along a predetermined wire guidance direction. Figure 1 In this process, the welding wire 2 extends vertically in the region following the exit of the housing 140 of the laser processing head 101 and preceding the processing area 31. The processing area 31 may include a tool center point or the tool center point may define the processing area 31.

[0065] The application of welding wire material can also be carried out gradually. Therefore, the laser beam 10 can be pulsed, that is, it can be repeatedly and alternately turned on and off, wherein the feeding of wire 2 starts and stops accordingly, or wire 2 advances and retracts reciprocally.

[0066] The laser wire welding system 100 can be used to create structures, especially cylindrical structures or welds, on the surface of the workpiece 3, such as... Figure 1 As shown by dashed line 32. During and / or between application steps, the processing area 31 can be displaced by moving the laser processing head 101 and / or the workpiece 3. The step duration can be between 100 ms and 2 s, for example, 400 ms. The structure can have a diameter of 1 mm to 5 mm, for example, 3 mm, and a height of 2 mm to 15 mm measured from the workpiece surface, for example, 6 mm or 10 mm.

[0067] Therefore, the laser wire welding system 100 shown can be used to 3D print on the workpiece 3 by properly manipulating the laser processing head 101, the wire feeding device 102 and the laser source 103.

[0068] The materials of wire 2 and workpiece 3 can be composed of titanium or aluminum or alloys containing at least one of these materials.

[0069] The laser processing head 101 is configured to irradiate the workpiece 3 with a laser beam 10. The laser processing head 101 may have one or more optical elements 110, 120, 130, 131, such as lenses, objectives, mirrors, prisms, axonal prisms, etc. The optical elements are used for guiding and shaping the laser beam 10. The optical elements may have transmission and / or reflection optical elements. For example, the laser processing head 101 has a collimating optics 110, a focusing optics 120, and a zoom optics or zoom objective (not shown). The focal position and / or focal position and focal diameter of the laser beam 10 can be adjusted, for example, by means of the optical elements. The laser processing head 101 may have a deflecting mirror 131 for deflecting the laser beam 10. For example, the deflecting mirror 131 can change the beam propagation direction of the laser beam 10 by 90 degrees. The deflecting mirror 131 may have an opening for the passage of the wire 2. Furthermore, the laser processing head 101 may have optical elements 130, such as axonal prisms and prisms, for generating a ring-shaped laser beam 10. Optical element 130 in Figure 1 The invention is exemplarily shown as a single optical element, but is not limited thereto. "Ring" can also mean that the laser beam 10 has a rotationally symmetric, especially rotationally symmetric, shape about the beam propagation direction.

[0070] According to other embodiments not shown, the laser wire welding system can also generate multiple laser beams and irradiate the processing area. The multiple laser beams can be arranged in a manner that is rotationally and / or symmetrical about the wire.

[0071] The arrangement of the laser beam 10 or more laser beams may be annular at least in the section along the wire 2, especially after exiting the housing of the laser processing head 101 and / or before entering the processing area 31 and / or in the processing area 31.

[0072] The wire conveying device 102 is configured to transport the wire 2 to the processing area 31. For this purpose, the wire conveying device 102 can be configured to transport the wire 2 from a wire reservoir, such as a wire roll (not shown), to the processing area 31 at a predetermined speed. Furthermore, the wire conveying device 102 can be configured to retract after passing through the processing area 31 or the wire guiding device 104. The wire conveying device 102 can be arranged on or within the laser processing head 101. In particular, the wire conveying device can be fixedly connected to the laser beam device 106 or the laser processing head 101. However, the invention is not limited thereto.

[0073] To guide the wire 2 into the processing area 31, a wire guiding device 104 may be provided. The wire guiding device 104 ensures that the wire 2 is guided into the processing area 31 substantially along a predetermined wire guiding direction. The wire guiding device 104 may be arranged or fixed to the housing 140 of the laser processing head 101, for example, at the lower end. Preferably, the wire guiding device 104 is arranged relative to the propagation direction of the laser beam 10 after the last optical element, such as the focusing optics 120, or after the last protective glass (not shown), but the invention is not limited thereto. According to the same non-limiting embodiment, and as... Figure 1 As shown, the wire 2 can first pass through the laser processing head 101 from the wire conveying device 2, and then exit from the laser processing head 101 or from the wire guiding device 104. The wire guiding device 104 can be part of the wire conveying device 2 and / or part of the laser processing head 101.

[0074] The laser beam 10, or the arrangement of the plurality of laser beams described previously, can extend coaxially with the predetermined wire guiding direction of the welding wire 2 at least along a segment of the wire 2. This means that the beam propagation direction and the wire guiding direction of the welding wire 2 can be at least partially coaxial and / or parallel and / or coincident with each other. For example, the laser beam 10 can extend coaxially with the wire 2 after passing through the deflector mirror 131 and / or after exiting the housing 140 of the laser processing head 101 and / or immediately before entering the processing area 31 and / or within the processing area 31. Furthermore, the laser beam 10 can irradiate the processing area 31 coaxially with the wire 2.

[0075] The laser source 103 is configured to change the laser beam, particularly to turn the laser beam 10 on and / or off and / or change the laser power. The filament conveying device 102 is configured to change the filament conveying, particularly to start the filament conveying, stop the filament conveying, change the filament conveying speed and / or change the filament conveying direction.

[0076] The control device 105 can be real-time. The control device 105 is configured to manipulate the laser beam device 106 and the wire transport device 102, particularly to perform a method for laser wire welding according to one aspect or embodiment disclosed herein. Furthermore, the laser wire welding system 100 may include a bus or bus system 107, which can also be real-time. The bus 107 is used to transmit control signals from the control device 105 to the laser beam device 106 and the wire transport device 104 of the laser wire welding system 100. Alternatively, the control device can be wirelessly connected to the laser beam device 106 and the wire transport device 104, for example, via Bluetooth, WLAN, or similar means.

[0077] The laser wire welding system 100 may include a camera unit 109. The camera unit 109 may be configured to observe the laser wire welding process and / or to detect the position of the wire 2 or the position of the wire tip.

[0078] Workpiece 3 or more workpieces can be constructed as plate-shaped and / or metal workpieces.

[0079] Figure 2 A flowchart illustrating a method for laser wire welding using a laser wire welding system according to an embodiment of the present invention is shown. This method can be performed using... Figure 1 The laser wire welding system 100 is executed.

[0080] Method 200 includes a first step 201, in which the wire feed device of the laser wire welding system is manipulated by means of a control device to change the wire feed. The change may, for example, include activating the wire feed. "Manipulation" means that the wire feed device receives a corresponding control signal from the control device, possibly via a bus.

[0081] Method 200 includes a second step 202, in which the laser beam device of the laser wire welding system is manipulated by means of a control device to change the laser beam. The change may, for example, include turning on the laser beam. "Manipulation" means that the laser beam device receives a corresponding control signal from the control device, possibly via a bus.

[0082] Here, the timing of the filament feeding control in step 201 and the timing of the laser beam control in step 202 are determined such that the timing of the change in filament feeding and the timing of the change in laser beam have a predetermined time interval between them.

[0083] In particular, the control of the filament feed and the control of the laser beam can be determined or performed taking into account the delay time of the filament feed equipment and / or the delay time of the laser beam equipment.

[0084] The delay time of a laser beam device can be defined as the duration from the time point at which the control signal used to change the laser beam is received, particularly the control signal used to change the laser beam, to the time point at which the laser beam changes accordingly.

[0085] The delay time of a laser beam device can specifically include an on-time delay. The on-time delay describes the duration between the receipt of the control signal for activating the laser beam and the on-time of the laser beam. Therefore, the timing of laser beam manipulation for activating the laser beam can be determined taking into account the on-time delay of the laser beam device.

[0086] The delay time of a filament conveying device can be defined as the duration from the time point at which the control signal used to change the filament conveying is received, in particular the time point at which the filament conveying changes accordingly.

[0087] The delay time of the yarn conveying equipment can specifically include a start-up delay time. The start-up delay time describes the duration between the receipt of the control signal used to start the yarn conveying and the start time of the yarn conveying. Therefore, the timing of the yarn conveying control used to start the yarn conveying can be determined taking into account the start-up delay time of the yarn conveying equipment.

[0088] According to the implementation, the change in filament feeding can be to stop filament feeding, and the change in the laser beam can be to turn off the laser beam. The above description applies accordingly.

[0089] Furthermore, the timing of wire feed control and laser beam control can be determined by taking into account the delay time of the control equipment. The delay time of the control equipment can include the processing delay time of the control equipment and / or the delay time of the bus or bus system of the laser wire welding system. The delay time of the control equipment can also be referred to as the "facility control delay time." When selecting a real-time control equipment or a real-time bus, the delay time is usually known in advance. Control can be performed, for example, via an Ethercat® bus, where the delay time is 1 ms in a standard implementation. If the control equipment is real-time, it also has a defined processing delay time within which the individual components of the laser wire welding system are controlled.

[0090] The described method allows for a precisely defined time interval between the actual change point in the filament feeding (start in this example) and the actual change point in the laser beam (on in this example). The time interval can be arbitrarily chosen. In particular, the time interval can be set to zero, synchronizing the changes in filament feeding and the laser beam.

[0091] Depending on the application or process control, it may be advantageous to first heat the workpiece with the laser beam only, and then melt the wire. In this case, the laser beam device is first operated to turn on the laser beam or increase its power, and then, after a defined time interval, the wire feed device is operated to start the wire feed and advance the wire tip into the processing area or the laser beam. For this purpose, the laser beam may be turned off again before the feed motion begins, so that it is turned on again when the wire tip reaches the focal point of the laser beam.

[0092] In other cases, it is advantageous that the workpiece is not heated, but the wire tip is completely and precisely melted. For this purpose, the laser beam should be turned on or its power increased when the wire tip reaches the processing area or the focal point of the laser beam. The method according to aspects and embodiments of the invention allows for precise timing coordination between the wire feed changes and laser beam changes required for this purpose.

[0093] Additional adjustments can be incorporated into the laser wire welding method, which are performed, for example, by a control device. These adjustments can utilize signals from sensors selected from: OCT sensors, cameras, photodiodes, lidar sensors, pyrometrischer sensors, thermal imagers, and thermal sensors, especially those with spatial resolution.

[0094] Furthermore, when contact between the wire and the workpiece is lost, an electrical contact signal can be used to shut off the laser beam. Additionally, the contact signal can be used to determine the position of the wire tip.

[0095] Figure 3 A flowchart illustrating a method for determining a delay time according to an embodiment of the present invention is shown. (In conjunction with...) Figure 3 The described method may be part of the laser wire welding method according to aspects and embodiments of the present invention. For example, the method for determining the delay time may be... Figure 2 The steps 201 and 202 of method 200 occur before these steps.

[0096] By combining Figure 3 The method described can be used to calculate the delay time of a laser beam device.

[0097] Method 300 is described for the turn-on delay time of a laser beam device, but is applicable to every change to the laser beam by the laser beam device, and therefore also applicable, for example, to turning off and changing (increasing or decreasing) the laser beam power.

[0098] According to the implementation method, the activation delay time refers to the duration between the time when the laser beam device receives the control signal for activating the laser beam and the actual activation time of the laser beam.

[0099] In the first step 301, for example, the duration between the laser beam manipulation time point and the laser beam on-time point is measured, i.e., the actual response of the laser beam device, the so-called laser delay. The actual on-time point of the laser beam can be defined as the time point when the laser beam reaches a predetermined laser beam power. This duration can then be stored in the control device as the on-time delay time (step 302).

[0100] The timing of laser beam control can refer to the point in time when the laser beam device receives the control signal used to turn on the laser beam.

[0101] There are several possibilities for measuring the delay time of a laser beam device. One possibility is, for example, moving the laser processing head relative to a reference plate at a constant speed. When the laser processing head reaches a specific position, a control signal is sent to turn on the laser beam ("laser on" signal). When it reaches a second position, a control signal is given to turn off the laser beam ("laser off" signal). This generates a mark with the laser; however, this mark is offset relative to the start and end points, i.e., it only begins at the starting position and only ends after the end position. The on-time delay ("laser on delay") can be determined from the speed and the lateral offset between the first position and the mark's starting point. The off-time delay ("laser off delay") can be determined accordingly from the lateral offset between the second position and the mark's ending point.

[0102] The method 300 described for the laser beam device can be used accordingly to determine the delay time of the wire conveying device. This refers to the time offset between the receipt of the wire conveying start signal (“wire conveying start signal”) and the actual start of wire conveying. Wire movement can be determined using a camera, where the start signal is used as a trigger. Alternatively, the delay time of the wire conveying device can be based on the manufacturer's specifications.

[0103] In combination Figure 2 In the described laser wire welding method, the wire can be fed from a defined and / or pre-given starting position. In other words, wire feeding is initiated from a defined and / or pre-given starting position.

[0104] Figure 4a A flowchart illustrating a method for determining the starting position of a filament and, possibly, guiding it to a pre-given starting position is shown. Figure 4a The position of the filament tip in this method is shown. This method can be performed before starting the filament feed. This allows for a simple, fast, reliable, and accurate determination of the filament's starting or initiating position.

[0105] Figure 4b and 4c Different positions of the filament are shown. The position of the filament is referred to below as the position of the filament tip, but the invention is not limited thereto. Furthermore, in Figure 4b and Figure 4c For better representation, only the position of the silk tip is shown. Figure 4b Steps 401-403 are explained. Figure 4c Step 404 is explained.

[0106] First, the starting position of the wire is determined. To do this, the wire is advanced from an unknown position 410 using a wire feeding device (step 401), and the contact time point at which the wire, especially the tip of the wire, touches the object 411, such as a workpiece in a laser wire welding method, is determined (step 402). Therefore, the wire can be advanced in step 401 until it contacts the object 411 (step 402).

[0107] Determining the contact time point may include detecting or probing an electrical signal. This electrical signal can be generated through contact between the wire, particularly the wire tip, and an object. Alternatively or additionally, determining the contact time point may include detecting the force required for wire feeding, and the increase in force caused by contact with the object can be used to determine the contact time point.

[0108] Subsequently, the position of the filament at the contact time point is determined as the starting position 420 of the filament (step 403).

[0109] Alternatively or additionally, the starting position of the wire can be determined using the camera unit 109 of the laser wire welding system or by a camera-based method.

[0110] The determined starting position can be compared with the pre-defined starting position 430. The determined starting position can be determined as or used as the pre-defined starting position. For example... Figure 4b As shown, alternatively, starting from the determined starting position 420, the wire can be retracted by a defined length or distance (indicated by the dashed arrow) to bring it to a pre-given starting position 430 (optional step 404). The defined length can be derived from a comparison or difference between the determined starting position and the pre-given starting position. The pre-given starting position can be located within a pre-given machining area and / or correspond to the tool center point of the laser wire welding system.

[0111] Advantageously, the distance between the workpiece (e.g., object 411) and the wire tip or the focal point of the laser beam can be defined and precisely, and therefore ideally, adjusted for the corresponding laser wire welding method and the corresponding process. Depending on the application, it may also be advantageous, for example, that the wire is always in contact with the workpiece. This can also be achieved by determining the starting position of the wire and guiding the wire to the starting position.

[0112] Subsequently, laser power and wire feed can now be controlled synchronously or at mutually defined time intervals (also known as time offsets) according to the methods described herein to achieve optimal welding results. This is now feasible without issues within the system's delay time.

Claims

1. A method for laser wire welding using a laser wire welding system (100), comprising the following steps: Manipulate (201) the wire feeding device (102) of the laser wire welding system to change the wire feeding, The laser beam device (106) of the laser wire welding system is manipulated (202) to change the laser beam (10). In this process, taking into account the delay time of the laser beam device (106) and / or the delay time of the filament conveying device (102), the filament conveying device (102) is manipulated (201) to start the filament conveying and the laser beam device (106) is manipulated (202) to turn on the laser beam (10), such that the change time point of the filament conveying and the change time point of the laser beam have a predetermined time interval between each other.

2. The method according to claim 1, wherein, The time interval is greater than or equal to zero.

3. The method according to claim 2, further comprising (301) determining (301) the delay time of the laser beam device (106) and storing (302) the delay time of the laser beam device (106), and / or In addition, it includes obtaining (301) the delay time of the filament conveying device (102) and storing (302) the delay time of the filament conveying device (102).

4. The method according to any one of the preceding claims, wherein, The changes to the yarn feeding include starting the yarn feeding, stopping the yarn feeding, changing the yarn feeding speed and / or changing the yarn feeding direction; and / or The modification of the laser beam includes turning the laser beam on, turning the laser beam off, changing the laser beam power, and / or changing the focal position of the laser beam.

5. The method according to any one of the preceding claims, wherein, The change in the filament delivery includes initiating the filament delivery, and the delay time of the laser beam device (106) includes an on-delay time, wherein the on-delay time refers to the duration between the time point for laser beam manipulation to activate the laser beam (10) and the on-delay time of the laser beam (10), and / or The change of the laser beam includes turning on the laser beam, and the delay time of the filament delivery includes a start-up delay time, wherein the start-up delay time refers to the duration between the time point for starting the filament delivery control and the start time point of the filament delivery.

6. The method according to any one of the preceding claims, further comprising the following steps: Proceed (401) filament (2) from unknown position (410). Find the contact time point (402), at which the filament (2) touches the object (411). Determine (403) the position of the filament (2) at the contact time point, especially the position of the filament tip, as the starting position (420) of the filament (2).

7. The method according to claim 6, wherein, The determination of the contact time point (402) includes detecting an electrical signal generated when the filament (2), especially the tip of the filament, touches the object (411), and / or The determination of the (402) contact time point includes detecting the force required for the filament delivery.

8. The method according to any one of claims 1 to 5, further comprising using the camera unit (109) of the laser wire welding system (100) to determine (403) the position of the wire (2) as the starting position (420) of the wire.

9. The method according to any one of claims 6 to 8, further comprising one of the steps (404): Set the obtained starting position (420) as the starting position (430), or Starting from the desired starting position (420) of the filament (2), retract the filament (2) to bring it to the predetermined starting position (430).

10. The method according to any one of the preceding claims, further comprising: Operate (201) the filament conveying device (102) to stop the filament conveying. Operate (202) the laser beam device (106) to shut down the laser beam (10). In this process, taking into account the delay time of the laser beam device (106) and / or the delay time of the wire conveying device (102), the wire conveying device (102) is manipulated (201) to stop the wire conveying and the laser beam device (106) is manipulated (202) to turn off the laser beam (10) such that the stopping time of the wire conveying and the turning off time of the laser beam (10) have a predetermined second time interval between each other.

11. The method according to claim 10, wherein, The delay time of the laser beam device (106) includes a shutdown delay time, wherein the shutdown delay time refers to the duration between the time point for shutting down the laser beam control of the laser beam (10) and the shutdown time point of the laser beam (10), and / or The delay time for the filament feeding includes a stop delay time, wherein the stop delay time refers to the duration between the point in time when the filament feeding operation is used to stop the filament feeding and the point in time when the filament feeding stops.

12. The method according to any one of the preceding claims, wherein, The laser beam (10) extends coaxially with the filament (2) at least along a segment of the filament (2), and / or Wherein, the laser beam (10) is constructed in a ring shape, and / or The laser beam (10) has a rotationally symmetric and / or rotationally symmetric shape, or multiple laser beams are arranged around the filament (2) in a rotationally symmetric and / or rotationally symmetric manner.

13. The method according to any one of the preceding claims, wherein the wire (2) and / or workpiece is composed of or includes the following materials: titanium (Ti), aluminum (Al), TiAl, titanium alloys, and / or aluminum alloys, especially 5000 series, 6000 series or 7000 series aluminum alloys.

14. The method according to any one of the preceding claims, wherein, The laser beam (10) and / or the filament delivery are pulsed, and / or Wherein, the filament (2) alternately advances and retracts, and / or The laser beam (10) is repeatedly turned on and off, and the filament feed is repeatedly started and stopped, such that each start time of the filament feed and each turn-on time of the laser beam (10) have a predetermined first time interval between each other, and each stop time of the filament feed and the turn-off time of the laser beam (10) have a predetermined second time interval between each other.

15. The method according to any one of the preceding claims, wherein, The method is used for laser cladding, and / or The method further includes: The filament material (2) is gradually applied to the workpiece (3), wherein the duration of the step is between 100 ms and 2 s, preferably between 300 ms and 500 ms, particularly preferably 400 ms, and / or The wire material (2) is applied to the workpiece (3) in the form of a structure, wherein the structure is a cylindrical structure and / or has a diameter between 1 mm and 5 mm and / or a height between 5 mm and 15 mm, especially between 2 mm and 10 mm, and / or a wall thickness between 1 mm and 3 mm.

16. A laser wire welding system (100), comprising: A laser beam device (106) is configured to generate a laser beam (10). The filament conveying device (102) is configured to convey filaments (2) to a pre-defined processing area (31), and A control device (105) is configured to operate the laser beam device (106) and the wire conveying device (105). The control device (105) is configured to perform the method according to any one of the preceding claims.

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