Method for producing a weld seam, and laser welding machine

Abstract

The invention relates to a method for producing a weld seam by means of a laser beam (18). A laser spot (54) moves relative to a first component (12) and / or a second component (14). The movement of the laser spot (54) can be resolved into a first movement component (50) and a second movement component (52). The first movement component (50) is a linear movement. The second movement component (52) is a movement substantially along an ellipse. A ratio of a maximum speed of the movement of the laser spot (54) to a minimum speed of the movement of the laser spot (54) has a value in a range from 1 to 2, preferably in a range from 1 to 1.5.

Description

[0001] Title: Method for producing a weld seam and laser welding machine

[0002] Description

[0003] The invention relates to a method for producing a weld seam and a laser welding machine.

[0004] A weld is often used to join a first component to a second component. One or both components may have a base body with a coating. The base body and the coating material can differ. For example, the base body may be made of a corrosive material, and the coating may serve as corrosion protection for the base body.

[0005] When coated components are welded together, agglomerations of coating material often form within the weld seam. In other words, areas with a high concentration of coating material can occur along the weld. These coating material agglomerations can reduce the stability and / or strength of the weld. Therefore, if either component has a coating, the coating is often removed before welding. Removing the coating can prevent coating material agglomeration in the weld. WO 2019 / 030249 A1 describes a method for joining a first sheet and a second sheet. The first sheet or the second sheet has a layer made of aluminum or an aluminum alloy.The two circuit boards are joined together by laser welding, in which the laser beam performs a linear movement along a welding direction and oscillating movements essentially perpendicular to the welding direction.

[0006] The invention aims to provide a method for producing a weld seam and a laser welding machine, each with improved properties, in particular enabling the production of a weld seam with high stability and strength.

[0007] The invention solves this problem by providing a method with the features of claim 1 and a laser welding machine with the features of claim 11. Advantageous embodiments and further developments of the invention are set out in the dependent claims.

[0008] A method according to the invention serves to produce a weld between a first component and a second component using a laser beam. The method comprises: generating the laser beam; and producing the weld by guiding the laser beam over the first component and / or over the second component. During its guidance over the first component and / or over the second component, the laser beam strikes the first component and / or the second component, forming a laser spot. As the laser beam is guided over the first component and / or over the second component, the laser spot moves relative to the first component and / or the second component. The movement of the laser spot can be decomposed into a first movement component and a second movement component. The first movement component is a linear movement. The second movement component is a movement essentially along an ellipse.A quotient, in particular a magnitude of the quotient, of the division of a maximum speed of movement of the laser spot by a minimum speed of movement of the laser spot has a value in a range of 1 to 2, preferably in a range of 1 to 1.5, and more preferably a value of 1.

[0009] Advantageously, if the quotient has a value in the range of 1 to 2, the weld can be produced with a high feed rate without welding defects occurring during production, which is why the weld can be produced in a short time with high stability and strength.

[0010] In particular, if the quotient has a value in the range of 1 to 2, the materials of the first component and / or the materials of the second component can be homogeneously or uniformly mixed in a weld pool that forms during the welding process. This allows the materials to have a uniform distribution within the weld. In other words, this prevents the formation of agglomerations, which is why a weld with high stability and strength can be produced. Furthermore, if the first component and / or the second component has a coating, the need to remove the coating before welding is eliminated.

[0011] With a quotient outside the range of 1 to 2, undesirable material agglomerations can occur in the weld seam at the same feed rate, impairing the weld's stability and strength. To avoid these agglomerations when producing a weld seam with a quotient outside the range of 1 to 1.5, the feed rate can be reduced. This results in a longer weld seam production time. Consequently, this method can shorten the production time for the weld seam, thereby increasing productivity.

[0012] Another aspect of the process is that the avoidance of agglomeration makes the weld suitable for heat treatment. In particular, the absence of agglomeration allows the weld to be heat treated while still meeting the required strength specifications.

[0013] Another aspect of the process may be that if the quotient has a value in the range of 1 to 2, welds with a high width can be produced in a short time.

[0014] Another aspect of the process is that it avoids critical limiting speeds of the laser spot movement, at which welding defects and / or agglomeration can occur. Another aspect of the process is that it eliminates the need to increase the cross-sectional area of ​​the weld joint for welding.

[0015] Another aspect of the process may be that it enables the production of a metallurgically and geometrically uniform weld seam.

[0016] One or both components can have a base body with a coating. The base body material and the coating material can differ from each other.

[0017] The base body can be made of a corrosive material, for example iron or steel, preferably alloyed with boron. Alternatively, the base body can be made of Gen3 steel or AHSS (Advanced High-Strength Steel).

[0018] The coating can be a corrosion-resistant coating for the base body. In particular, the coating can prevent oxidation of the base body. The base body can be coated on at least two opposite sides.

[0019] The coating can be made of a zinc alloy, an aluminum alloy, or an aluminum-silicon alloy. In other words, the coating can be a zinc coating, an aluminum coating, or an aluminum-silicon coating.

[0020] The zinc alloy can be an alloy with a zinc content of at least 75%, 80%, 90%, 95%, or 98% by weight. The zinc alloy can also be an alloy with a zinc content of at most 100% by weight.

[0021] The aluminum alloy can be an alloy with a minimum aluminum content of 75%, 80%, 90%, 95%, or 98% by weight. The aluminum alloy can also be an alloy with a maximum aluminum content of 100% by weight.

[0022] The aluminum-silicon alloy can be an alloy with a minimum weight content of 75%, 80%, 90%, 95%, or 98% aluminum-silicon (AlSi). The aluminum-silicon alloy can also be an alloy with a maximum weight content of 100% aluminum-silicon. The first component can be designed as a sheet. In particular, the width and / or length of the first component can be more than five times, and especially ten times, its thickness. The first component can have a thickness in the range of 0.1 mm to 5 mm, and especially 0.5 mm to 4 mm.

[0023] The second component can be designed as a sheet metal part. In particular, the width and / or length of the second component can be more than five times, and in particular more than ten times, its thickness. The second component can have a thickness in the range of 0.1 mm to 5 mm, and in particular more than 0.5 mm to 4 mm.

[0024] The first component and the second component can be identical in design, in particular, of the same construction.

[0025] The first and second components can be arranged to form a lap joint, a butt joint, or a T-joint for the purpose of creating the weld. If the first and second components are arranged to form a T-joint, the weld can be a fillet weld.

[0026] The weld can serve to join the first component to the second component. The weld can have a width greater than 1.2 mm. The weld can have a transversely mirror-symmetrical cross-sectional geometry. The weld can have a constant weld depth.

[0027] The laser beam can be generated using a laser beam source. The laser beam source can be a fiber laser, a disk laser, or a slab laser.

[0028] The laser beam can, particularly immediately before impacting the first and / or second component, have a beam parameter product with a value of less than or equal to 8 mm*mrad (millimeters*milliradians), in particular 4 mm*mrad, preferably 2 mm*mrad. Advantageously, this allows the weld seam to have a constant width over its entire depth. A further advantage can be a reduction in the heat-affected zone.

[0029] The laser beam can be a single-mode laser beam. Preferably, the laser beam, particularly immediately before impacting the first component and / or the second component, can have a beam parameter product with a value in the range of 0.4 mm*mrad to 0.6 mm*mrad.

[0030] The laser beam can have a wavelength in the NIR (near-infrared) range. Specifically, the laser beam can have a wavelength ranging from 900 nm (nanometers) to 2300 nm.

[0031] The laser beam can be configured as a multi-mode laser beam with a power output greater than or equal to 3 kW (kilowatts).

[0032] The laser beam can have a core area and a ring area. The ring area can completely surround the core area. The ring area can also be adjacent to the core area. Advantageously, this can reduce the risk of spatter during the welding process.

[0033] The laser beam can have a ratio of core diameter to ring diameter ranging from 1:2 to 1:9, particularly 1:3, 1:4, or 1:6. This ratio can depend on the material from which the first and / or second component is made, or on the thickness of the first and / or second component. This allows the laser beam ratio to be adapted to the specific characteristics of the first and / or second component.

[0034] The laser spot can have a diameter ranging from 25 pm (micrometers) to 600 pm. A laser spot can be understood as an area of ​​the first component and / or the second component illuminated by the laser beam.

[0035] The Rayleigh length of the laser beam can be greater than or equal to 30%, and in particular 50%, of the thickness of the thinner of the two components. If the two components are of equal thickness, the Rayleigh length of the laser beam can be greater than or equal to 30%, and in particular 50%, of the thickness of the first component. This reduces the heat-affected zone that occurs during weld formation. Additionally, it allows the weld to have a constant width throughout its entire depth.

[0036] The creation of the weld seam can involve focusing the laser beam onto the first component and / or the second component, particularly using focusing optics. The laser beam's focal position can have a maximum distance of 4 mm. This can improve weld seam quality, especially by preventing weld defects such as seam sinkage, root pullback, spatter formation, or ejection. The focal position can be defined as the distance, in the direction of laser beam propagation, between a focus point of the laser beam and a contact point where the first and second components meet.

[0037] The focusing optics can include a lens or a curved mirror, in particular a concave mirror.

[0038] Guiding the laser beam across the first component and / or the second component can be achieved using a deflection device. The deflection device can be designed as a scanner optic, in particular as a galvanometer scanner.

[0039] The deflection device can be configured to deflect the laser beam such that the laser spot performs the movement. In one embodiment, the first component and / or the second component do not perform any relative movement with respect to the deflection device and / or the focusing optics.

[0040] Alternatively, the deflection device can be configured to deflect the laser beam in such a way that the laser spot performs the second movement component. The first movement component can be achieved by a relative movement of the first component and / or the second component with respect to the deflection device. This relative movement can be effected by means of a transport module. The transport module can be designed as a conveyor belt. This allows the weld seam to be produced "on the fly."

[0041] The deflection device may include focusing optics. For example, the deflection device may include a concave mirror for focusing the laser beam onto the first component and / or the second component, which is attached to a galvanometer drive.

[0042] The deflection device allows the laser beam to be deflected in an XY plane. The deflection device can perform an oscillatory motion to deflect the laser beam. The oscillation motion can have an amplitude ranging from 0.25 mm to 1 mm and a frequency ranging from 50 Hz (Hertz) to 200 Hz. The weld can be created by through welding. In other words, the weld depth can be equal to the sum of the thickness of the first component and the thickness of the second component. This allows the weld to be visually inspected for defects. Alternatively, the weld can be created by inset welding. This prevents material from a coating on one of the components, which is not melted during inset welding, from entering the weld.This can reduce the concentration of coating material in the weld seam.

[0043] The weld formation process can involve directing a process gas onto the weld pool that forms during the weld. This process gas can reduce or prevent a metal vapor flare and / or the formation of a thermal lens. A thermal lens can cause unwanted defocusing of the laser beam. The process gas can be nitrogen, compressed air, argon, or helium. Alternatively, the process gas can be a mixture of at least two gases selected from a group containing nitrogen, compressed air, argon, and helium.

[0044] The process gas can hit the first component and / or the second component at a volume flow rate in the range of 10 Nl / min (standard liters / minute or standard volume flow rate) to 20 Nl / min.

[0045] While the laser beam is guided across the first component and / or the second component, the width of a weld segment can be measured. The movement of the laser spot can be modified depending on the measured width of the weld segment. This measurement can be performed using optical coherence tomography. The laser spot's movement can be modified by changing the size of a minor axis of the ellipse and / or a major axis. The laser spot's movement can also be adjusted to maintain a constant weld width. This allows for automatic control of the weld width, particularly without human intervention.

[0046] A major axis of an ellipse can be understood as a straight line bounded by the ellipse and passing through its foci. A minor axis of an ellipse can be understood as a straight line bounded by the ellipse, perpendicular to the major axis, and passing through a center point of the ellipse.

[0047] The secondary axis and the first component of motion can be aligned parallel to each other and / or run parallel to each other. A dimension of the primary axis, in particular its length, can determine the width of the weld. In particular, the dimension of the primary axis, in particular its length plus a beam diameter, and the width of the weld can be equal in magnitude.

[0048] The first component of the motion can be called the first part of the movement, and the second component can be called the second part of the movement. Linear motion can be understood as motion along a straight line.

[0049] The first and second motion components can be modified independently of each other. This allows for an expansion of the usable process window.

[0050] If the quotient has the value 1, the maximum speed of the superimposed movement of the laser spot, i.e. the relative movement between laser spot and workpiece, and the minimum speed of the superimposed movement of the laser spot can have the same value.

[0051] If the quotient has the value 1.5, then the value of the maximum speed of movement of the laser spot can be equal to 1.5 times the value of the minimum speed of movement of the laser spot.

[0052] In a further development of the method, the ellipse of the second motion component has a major axis and a minor axis that differ in size, particularly length. This allows the weld to be produced at a higher speed for a given weld width.

[0053] In a further development of the method, the ellipse of the second motion component has a major axis and a minor axis that are equal in size, particularly in length. This allows the ellipse to be circular. This simplifies the programming of a control device that effects the second motion component of the laser spot by controlling a deflection device.

[0054] In a further development of the method, the speed of the first motion component is constant. This can simplify the execution of the method.

[0055] In a further development of the method, the speed of the second motion component is constant. This allows the value of the maximum speed of the laser spot's movement to differ from the value of the minimum speed of the laser spot's movement.

[0056] In a further development of the method, the speed of movement of the laser spot during the guidance of the laser beam over the first component and / or over the second component is greater than 0. This prevents the laser spot from coming to a standstill.

[0057] In a further development of the method, the speed of movement of the laser spot during the laser beam's movement over the first component and / or the second component is a maximum of 500 mm / s, preferably a maximum of 380 mm / s (millimeters per second). This prevents the occurrence of welding defects. Preferably, the speed of movement of the laser spot during the laser beam's movement over the first component and / or the second component is in the range of 250 mm / s to 380 mm / s. Within this range, rapid weld formation can be achieved while avoiding agglomeration.

[0058] In a further development of the method, the speed of the laser spot's movement changes as the laser beam passes over the first component and / or the second component. In other words, the speed of the laser spot's movement as the laser beam passes over the first component and / or the second component does not have to be constant. Therefore, the quotient can have a value other than 1.

[0059] In a further development of the method, an angular velocity of the second v(sin) fulfills <p-y cos <p)± Vg es (y 2 +l)-v 2 (cos <p+y sintp) 2 The motion component is subject to the condition: p = - ( y z +1 ) r - ■ ' st The angular velocity of the second component of motion, v is the velocity of the first component of motion, <p ist die momentane Winkelstellung in Bezug auf eine Nebenachse der Ellipse der zweiten Bewegungskomponente, vges is the speed of movement of the laser spot, r satisfies the condition r = . y satisfies the ^ / (asin <p) 2 +(d cos <p) 2

[0060] r- .. sin <p cos <p(b 2 -a 2 > . . . .. , , ,, .

[0061] Condition a ung a y ' = - ( —a sin <p ,), 2 +( ,b - cos <p) 2 a is a long a Let e ​​be half the minor axis of the ellipse of the second motion component, and b be half the length of the major axis of the ellipse of the second motion component. This ensures that the speed of the laser spot's movement remains constant as the laser beam passes over the first component and / or the second component. In other words, this allows the quotient to have the value 1.

[0062] In a further development of the process, the laser spot is moved along a trajectory while the laser beam is guided over the first component and / or the second component. The trajectory has a coverage ratio ranging from 5% to 90%, particularly 5% to 30%. This prevents edge notches at the weld root and ensures a consistent longitudinal weld depth. The coverage ratio describes the area enclosed by the trajectory of the spot center within one oscillation period relative to the area of ​​the ellipse described by the second movement component. Therefore, the coverage ratio is a characteristic parameter of the trajectory, ranging from 0% to 100%.

[0063] A laser welding machine according to the invention is designed for producing a weld seam between a first component and a second component. The laser welding machine comprises a laser beam source, a deflection device, and a control device. The laser beam source is designed to generate a laser beam. The deflection device is designed to direct the laser beam onto the first component and / or the second component. The control device is designed to control the deflection device. The laser welding machine is designed to produce the weld seam by carrying out a method according to one of the preceding claims.

[0064] The previously given description of the process can apply to laser welding machines with identical or functionally equivalent features. The laser beam source can be a solid-state laser, in particular in the form of a fiber laser, a disk laser, or a slab laser.

[0065] The control unit may include an electrical computing unit, in particular a computer and / or a microcontroller.

[0066] The control device can be configured to control the deflection device for the purpose of guiding the laser beam over the first component and / or over the second component.

[0067] The laser welding machine can have an optical fiber with a core and a cladding for generating the core region and the annular region of the laser beam. The core region and the annular region can be generated by coupling a portion of the laser beam's power into the core and a portion into the cladding.

[0068] The optical fiber can have a core diameter of 50 pm and a cladding diameter of 200 pm. Alternatively, the optical fiber can have a core diameter of 100 pm and a cladding diameter of 400 pm. Such core and cladding diameters can be particularly advantageous for multi-mode laser beams.

[0069] Alternatively, the optical fiber can have a core diameter of 25 pm and a cladding diameter of 100 pm. Such core and cladding diameters can be particularly advantageous for single-mode laser beams.

[0070] Preferably, the cladding between the core and the cladding can have a width with a value in the range of 3 pm to 90 pm.

[0071] The laser welding machine can have an optical element for coupling the laser beam into the optical fiber. This optical element can be a wedge-shaped splitter or a splice. The splice can be formed by attaching another optical fiber to the existing one using splicing technology. The additional optical fiber and the existing optical fiber can be offset from each other.

[0072] Further advantages and advantageous embodiments of the invention can be seen from the figures, their description, and the claims. All features disclosed in the figures, their description, and the claims can be essential to the invention, both individually and in any combination. The figures show:

[0073] Fig. 1 shows a schematic representation of a laser welding machine during the production of a weld between a first component and a second component.

[0074] Fig. 2 shows a schematic sectional view of the first component and the second component along a section line 11-11 according to Fig. 1.

[0075] Fig. 3 shows a schematic representation of a first movement component and a second movement component along which a laser spot is moved relative to the first component and the second component during the production of the weld seam.

[0076] Fig. 4 shows a schematic representation of the movement of the laser spot,

[0077] Fig. 5 shows a schematic representation of a trajectory along which the laser spot is moved over the first component and / or over the second component during the production of the weld seam, and

[0078] Fig. 6 shows a schematic representation of a trajectory of another embodiment.

[0079] Fig. 1 shows a laser welding machine 10. The laser welding machine 10 is designed to produce a weld seam between a first component 12 and a second component 14.

[0080] The laser welding machine 10 has a laser beam source 16. The laser beam source 16 is a solid-state laser, for example, in the form of a fiber laser. The laser beam source 16 serves to generate a laser beam 18. The laser beam 18 is a single-mode or multi-mode laser beam. The laser beam 18 has a wavelength in the range of 1030 to 1100 nm.

[0081] The laser beam 18 is guided via a first mirror 20 and a second mirror 22. The focusing lens 23 focuses the laser beam 18 onto the first component 12 and / or the second component 14. The two mirrors 20, 22 are each connected to a galvanometer drive, so that the two mirrors 20, 22 can be moved independently into different positions. This allows the laser beam 18 to be moved across the first component 12 and / or the second component 14 by means of the two mirrors 20, 22. Thus, the two mirrors 20, 22 together with the galvanometer drives form a deflection device 24 of the laser welding machine 10.

[0082] The laser welding machine 10 has a transport module 26. The transport module 26 is designed as a conveyor belt. The two components 12 and 14 are arranged on the transport module 26. During the welding process, the transport module 26 transports the two components 12 and 14 at a constant speed.

[0083] Fig. 1 shows that a further first component 30 and a further second component 32 are arranged on the transport module 26. After the weld seam has been produced in the two components 12, 14, the laser welding machine 10 produces a weld seam in the further components 30, 32 using the laser beam 18.

[0084] The laser welding machine 10 has a control unit 34. The control unit 34 is an electrical computing unit. The control unit 34 is used to control the deflection device 24 and the transport module 26.

[0085] Fig. 2 shows the two components 12, 14 along a section line 11-11 according to Fig. 1. The two components 12, 14 are arranged on the transport module 26 forming an overlap joint 36. The first component 12 and the second component 14 are identical in construction in the present embodiment. Therefore, a description of the first component 12 can apply analogously to the second component 14.

[0086] The two components 12, 14 are each a sheet. The width and / or length of each component 12, 14 is more than five times, in particular ten times, its thickness. The first component 12 has a thickness 38 in a range of 0.1 mm to 5 mm, in particular 0.5 mm to 4 mm. The second component 14 has a thickness 40 in a range of 0.1 mm to 5 mm, in particular 0.5 mm to 4 mm.

[0087] The first component 12 has a base body 42 and a coating 44, which is arranged on two opposite sides of the base body 42 of the first component 12. The second component 14 has a base body 46 and a coating 48, which is arranged on two opposite sides of the base body 46 of the second component 14. The base bodies 42 and 46 are each made of AHSS. The coatings 44 and 48 are corrosion-resistant coatings for the base bodies 42 and 46, respectively, for the purpose of preventing oxidation of the base bodies 42 and 46. The coatings 44 and 48 are made of an aluminum-silicon alloy with at least 95% aluminum-silicon (AlSi) by weight.

[0088] During the welding process, the laser beam 18 strikes the first component 12 in the area of ​​the overlap joint 36, forming a laser spot. The laser spot has a diameter ranging from 100 pm to 600 pm. This causes the two components 12 and 14 to melt locally. The molten materials of the two components 12 and 14 mix. After cooling, the molten materials solidify, forming the weld.

[0089] To achieve optimal mixing of the materials of the two components 12, 14 and thereby prevent agglomeration, the control unit 34 controls the transport module 26 and the deflection device 24 such that the laser beam 18, in particular the laser spot, is guided over the two components 12, 14 with a movement relative to them. This guides the laser spot along a trajectory over the two components 12, 14.

[0090] The movement of the laser spot can be decomposed into a first movement component and a second movement component. Fig. 3 shows the first movement component 50 and the second movement component 52.

[0091] The first motion component 50 is a linear motion. The first motion component 50 is effected by means of the transport module 26. The speed at which the first motion component 50 is executed is constant.

[0092] The second motion component 52 is a movement along an ellipse. The second motion component 52 is effected by means of the deflection device 24. The speed at which the second motion component 52 is executed can be constant or variable.

[0093] Fig. 4 schematically shows the laser spot 54, the first movement component 50, and the second movement component 52. The ellipse of the second movement component 52 has a major axis 56 and a minor axis 58. The minor axis 58 and the first movement component 50 are aligned parallel to each other. A quantity, in particular the length of the major axis 56, determines the width of the weld.

[0094] The control unit 34 controls the transport module 26 and the deflection device 24 such that the speed of movement of the laser spot 54 relative to the two components 12, 14 is not equal to 0 during the welding process. This prevents the laser spot 54 from coming to a standstill while the laser beam 18 is guided over the two components 12, 14.

[0095] The control unit 34 controls the transport module 26 and the deflection device 24 such that the speed of movement of the laser spot 54 relative to the two components 12, 14 during the welding process is a maximum of 380 mm / s. In particular, the control unit 34 can control the transport module 26 and the deflection device 24 such that the speed of movement of the laser spot 54 during the welding process has a value in the range of 250 mm / s to 380 mm / s.

[0096] The control unit 34 can control the transport module 26 and the deflection device 24 in such a way that the value of the speed of movement of the laser spot 54 relative to the two components 12, 14 changes during the production of the weld seam.

[0097] Alternatively, the control unit 34 can control the transport module 26 and the deflection device 24 such that the speed of movement of the laser spot 54 relative to the two components 12, 14 remains constant during the welding process. The constant speed of movement of the laser spot 54 is then achieved by

[0098] if the condition is met:

[0099]

[0100] < ' st ' e Angular velocity of the second component of motion 52. v is the velocity of the first component of motion 50. p is the instantaneous angular position with respect to the minor axis 58 of the ellipse of the second component of motion 52. v ges The speed of movement of the laser spot is 54. r satisfies the condition r = . Y satisfies the condition y =

[0101]

[0102] < < — a is a length of half V(asin <p) 2+(b cos <p) 2 r a a r (a sin <p) 2 +(b cos <p) 2 a The minor axis of the ellipse of the second motion component 52. b is a length of half the major axis of the ellipse of the second motion component 52. Fig. 5 shows the trajectory 62 in an XY plane along which the laser spot 54 is guided during the creation of the weld. A width 64 of the trajectory 62 is defined by the size, in particular the length, of the major axis of the ellipse of the second motion component 52. The width 64 of the trajectory 62 determines a width of the weld.

[0103] When the laser spot 54 is moved at a changing speed relative to the two components 12, 14, the speed of the laser spot 54 is maximum at a first position 66 of the trajectory 62 and minimum at a second position 68 of the trajectory 62. The maximum speed at the first position 66 results from the fact that the first motion component 50 and the second motion component 52 are in the same direction at the first position 66. The minimum speed at the second position 68 results from the fact that the first motion component 50 and the second motion component 52 are in opposite directions at the second position 68.

[0104] In Fig. 5, the maximum speed 70 is shown at the first position 66 and the minimum speed 72 at the second position 68 by means of an arrow.

[0105] A quotient of the division of the maximum speed 70 of the movement of the laser spot 54 by the minimum speed 72 of the movement of the laser spot 54 has a value in a range of 1 to 2, preferably in a range of 1 to 1.5 and more preferably a value of 1.

[0106] If the quotient has the value 1, then the maximum speed 70 of the movement of the laser spot 54 and the minimum speed 72 of the movement of the laser spot 54 have the same value.

[0107] If the quotient has a value other than 1, the magnitudes of the maximum speed 70 of the movement of the laser spot 54 and the minimum speed 72 of the movement of the laser spot 54 differ from each other.

[0108] By ensuring that the quotient has a value in the range of 1 to 2 and simultaneously that the speed of movement of the laser spot 54 relative to the two components 12, 14 does not exceed a value of 380 mm / s, the materials of the two components 12, 14 are optimally mixed during the welding process and no agglomeration forms. Figure 6 shows a trajectory 62 of a further embodiment, where the same reference numerals are used for identical and functionally equivalent elements, and reference can therefore be made to the above descriptions of the embodiment shown in Figures 1 to 5, so that essentially only the existing differences are discussed.

[0109] The laser welding machine 10 can be configured to generate a further laser beam which strikes the two components 12, 14, forming another laser spot. The laser beam 18 and the further laser beam can have the same beam properties.

[0110] The second laser spot performs a further movement by guiding the second laser beam over the two components 12, 14 relative to the two components 12, 14. A further trajectory 74 of the further movement of the second laser spot is shown as a dashed line in Fig. 6. In particular, Fig. 6 shows that, for the production of the weld seam, the laser spot 54 and the second laser spot are guided section by section simultaneously over the two components 12, 14.

[0111] The speed of movement of laser spot 54 and the speed of movement of the other laser spot can be the same.

[0112] Trajectory 62 and the further trajectory 74 can be identical. Trajectory 62 and the further trajectory 74 are arranged offset from each other, particularly in the X-direction or in the direction of the first motion component 50.

Claims

Patent claims 1. Method for producing a weld between a first component (12) and a second component (14) using a laser beam (18), wherein the method comprises: Generating the laser beam (18), Producing the weld seam by guiding the laser beam (18) over the first component (12) and / or over the second component (14), wherein the laser beam (18) strikes the first component (12) and / or the second component (14) while being guided over the first component (12) and / or over the second component (14) forming a laser spot (54), wherein the laser spot (54) performs a movement relative to the first component (12) and / or the second component (14) by guiding the laser beam (18) over the first component (12) and / or over the second component (14), wherein the movement of the laser spot (54) can be decomposed into a first movement component (50) and a second movement component (52), where the first motion component (50) is a linear motion, where the second motion component (52) is a motion essentially along an ellipse, wherein a quotient of the division of a maximum speed of movement of the laser spot (54) by a minimum speed of movement of the laser spot (54) has a value in a range of 1 to 2, preferably in a range of 1 to 1.

5.

2. Method according to claim 1, wherein the ellipse of the second motion component (52) has a major axis (56) and a minor axis (58) which differ in size, in particular length.

3. Method according to claim 1 , wherein the ellipse of the second motion component (52) has a major axis (56) and a minor axis (58) which are equal in size, in particular length.

4. Method according to any of the preceding claims, wherein the velocity of the first motion component (50) is constant.

5. Method according to any one of the preceding claims, where the velocity of the second component of motion (52) is constant.

6. Method according to any of the preceding claims, where a value of the speed of movement of the laser spot (54) during the guiding of the laser beam (18) over the first component (12) and / or over the second component (14) is greater than 0.

7. Method according to any of the preceding claims, wherein a value of the speed of movement of the laser spot (54) during the guiding of the laser beam (18) over the first component (12) and / or over the second component (14) is a maximum of 500 mm / s, preferably a maximum of 380 mm / s.

8. Method according to any of the preceding claims, wherein a value of the speed of movement of the laser spot (54) changes during the guiding of the laser beam (18) over the first component (12) and / or over the second component (14).

9. Method according to any one of the preceding claims 1 to 7, where an angular velocity of the second component of motion (52) satisfies the condition: < < < where <p die Winkelgeschwindigkeit der zweiten Bewegungskomponente (52), v die Geschwindigkeit der ersten Bewegungskomponente (50), p die momentane Winkelstellung in Bezug auf eine Nebenachse der Ellipse der zweiten Bewegungskomponente (52), v gesthe speed of movement of the laser Spots (54), r the condition r = is satisfied, y the condition y = < < sin cos <p(ö 2 -a 2 ,■ , , ,, . . , , , , .. - ( —a sin <p ,), 2 + ,b - cos <p 7)7 2 10. Method according to any one of the preceding claims, wherein the laser spot (54) is moved along a trajectory (62) while guiding the laser beam (18) over the first component (12) and / or over the second component (14), - wherein the trajectory (62) has a coverage ratio with a value in the range of 5% to 90%, in particular 5% to 30%.

11. Laser welding machine (10) for producing a weld seam between a first component (12) and a second component (14), comprising: - a laser beam source (16) for generating a laser beam (18), a deflection device (24) for directing the laser beam (18) onto the first component (12) and / or the second component (14), and a control device (34) for controlling the deflection device (24), wherein the laser welding machine (10) is configured to produce the weld seam by performing a method according to one of the preceding claims.

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