Laser welder and laser welding method for rectangular wire

Abstract

To provide a laser welder that can weld a pair of rectangular wires, without leaving corner parts of the rectangular wires, without plumping up welded parts excessively, and without deflecting the welded parts.SOLUTION: When a width of a gap between a side S1 and a S2 of rectangular wires 71 and 72 is zero, a laser welder emits laser beams to the apical surfaces of the rectangular wires 71 and 72, by a reference processing distance L0, at a reference welding speed V0, and with a central part of a side S3 set as an emission-starting position of a laser beam, so as to weld the rectangular wires 71 and 72. When the gap width is greater than zero and is in a first range including a first gap amount, the laser welder emits laser beams to the apical surfaces of the rectangular wires 71 and 72, by the reference processing distance L0, at the reference welding speed V0, and with a position offset from the central part of the side S3 toward the rectangular wire 72 by a distance corresponding to a half of the gap amount set as an emission starting position of a laser beam, so as to weld the rectangular wires 71 and 72.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a laser welding machine and a laser welding method for rectangular wires. [Background technology]

[0002] In motors used in electric or hybrid vehicles, both ends of radially adjacent segment coils of multiple U-shaped bent segment coils attached to a core are welded by a laser welding machine (see Patent Documents 1 and 2). Both ends of the radially adjacent segment coils are a pair of rectangular wires. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-20340 A [Patent Document 2] International Publication No. 2019 / 159737 Summary of the Invention [Problem to be solved by the invention]

[0004] When a pair of rectangular wires is welded by a laser welding machine, if the corners (edges) of the rectangular wires remain or if the molten part formed by melting the ends of the pair of rectangular wires swells excessively, this will result in a defective weld. The former type of defective weld is caused by insufficient melting of the metal at the end, while the latter type of defective weld is caused by excessive melting of the metal at the end. In addition, a defective weld will also occur if the molten part is biased toward one of the pair of rectangular wires. If there is a defective weld in the welded pair of rectangular wires, the end cap that should be attached to the end cannot be attached, and the motor will be defective.

[0005] There is a need for a laser welding machine and a laser welding method for flat wires that can weld a pair of flat wires without leaving any corners of the flat wires, without the molten part expanding excessively, and without the molten part being biased toward one of the pair of flat wires. [Means for solving the problem]

[0006] A first aspect of one or more embodiments includes a sensor that measures a gap amount between a first side of the first rectangular wire and a second side of the second rectangular wire that face each other at the end surfaces of the first and second rectangular wires that are adjacent to each other to be welded, and a control device that controls the irradiation position of a laser beam irradiated to the first and second rectangular wires and the movement of the laser beam to weld the first and second rectangular wires, and the control device controls the irradiation position of the laser beam irradiated to the first and second rectangular wires and the movement of the laser beam when the gap amount measured by the sensor is 0 at the end surface of the first rectangular wire. The center of a third side opposite to the first side is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set as a reference welding speed, and the laser beam is moved from the irradiation start position along a moving direction perpendicular to the first and third sides by a reference processing distance to an intermediate portion of the tip surface of the second rectangular wire to weld the first and second rectangular wires, and if the gap amount measured by the sensor exceeds 0 and is within a first range up to the first gap amount, 1 / 2 of the gap amount from the center of the third side is welded. The position offset to the second rectangular wire side by a first offset amount, which is a distance of 0, from the center of the third side is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to the reference welding speed, and the laser beam is moved from the irradiation start position by the reference processing distance along the moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, and if the gap amount measured by the sensor is in a second range exceeding the first gap amount to the second gap amount, the position offset to the second rectangular wire side by a distance obtained by adding the first offset amount, which is a distance of 1 / 2 of the gap amount, and a predetermined second offset amount exceeding 0 is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to the reference welding speed, and the laser beam is moved from the irradiation start position by the reference processing distance along the moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, and if the gap amount measured by the sensor is in a third range exceeding the second gap amount,The present invention provides a laser welder that controls a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is half the distance of the gap amount, as the irradiation start position of the laser beam, sets the moving speed of the laser beam to a welding speed faster than the reference welding speed, and moves the laser beam from the irradiation start position along a moving direction perpendicular to the first and third sides by a processing distance longer than the reference processing distance to weld the first and second rectangular wires.

[0007] In a second aspect of one or more embodiments, a gap amount between a first side of the first rectangular wire and a second side of the second rectangular wire facing each other at each end surface of a first and second rectangular wire to be welded adjacent to each other is measured by a sensor, and if the gap amount measured by the sensor is 0, a center of a third side on the end surface of the first rectangular wire opposite to the first side is set as a laser beam irradiation start position, a moving speed of the laser beam is set to a reference welding speed, and the laser beam is moved from the irradiation start position to the first and third rectangular wires. a reference processing distance along a moving direction perpendicular to the third side to reach a middle portion of the tip surface of the second rectangular wire, and the first and second rectangular wires are welded together, and if the gap amount measured by the sensor exceeds 0 and is within a first range up to a first gap amount, a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is a distance of 1 / 2 of the gap amount, is set as an irradiation start position of the laser beam, and the moving speed of the laser beam is set to the reference welding speed, and the laser beam is welded from the irradiation start position to the reference welding speed. the first and second rectangular wires are welded by moving the reference processing distance from the center of the third side along a moving direction perpendicular to the first and third sides, and if the gap amount measured by the sensor is in a second range from the first gap amount to a second gap amount, the position offset from the center of the third side toward the second rectangular wire by a distance obtained by adding a first offset amount, which is a distance of 1 / 2 of the gap amount, and a predetermined second offset amount exceeding 0 is set as the irradiation start position of the laser beam, and the moving speed of the laser beam is set to the reference welding speed, The laser beam is moved from the irradiation start position by the reference processing distance along a moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, and if the gap amount measured by the sensor is within a third range exceeding the second gap amount, a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is a distance of 1 / 2 of the gap amount, is set as the irradiation start position of the laser beam, and the moving speed of the laser beam is set to a welding speed faster than the reference welding speed,The present invention provides a laser welding method for flat wires, which welds the first and second flat wires by moving the first and second flat wires from the irradiation start position along a moving direction perpendicular to the first and third sides by a processing distance longer than the reference processing distance. Effect of the Invention

[0008] According to one or more embodiments of the laser processing machine and the laser welding method for flat square wire, a pair of flat square wires can be welded without leaving any edges of the flat square wire, without the molten part expanding excessively, and without the molten part being biased toward one of the pair of flat square wires. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a laser processing machine according to one or more embodiments. [Diagram 2] FIG. 2 is a perspective view illustrating a galvanometer scanner that may be included in a laser processing machine according to one or more embodiments. [Diagram 3] FIG. 3 is a plan view showing a pair of rectangular wires in contact with each other. [Figure 4] FIG. 4 is a plan view showing a pair of rectangular wires spaced apart from each other. [Diagram 5] FIG. 5 is a diagram illustrating a first comparative example for comparison with the method for laser welding rectangular wire according to one or more embodiments. [Figure 6] FIG. 6 is a diagram illustrating a second comparative example for comparison with the method for laser welding rectangular wire according to one or more embodiments. [Figure 7] FIG. 7 is a diagram illustrating a third comparative example for comparison with the method for laser welding rectangular wire according to one or more embodiments. [Figure 8] FIG. 8 illustrates a method for laser welding rectangular wire according to one or more embodiments. [Figure 9A] FIG. 9A is a side view showing an edge remaining weld defect. [Figure 9B] FIG. 9B is a side view showing a welding defect in which the fusion width of the fusion zone is too wide. [Figure 9C] FIG. 9C is a side view showing a welding defect in which the fusion zone is biased. [Figure 10] FIG. 10 is a diagram showing a preferable offset amount when the gap amount between a pair of rectangular wires exceeds 0 mm and is in a first range up to a first gap amount. [Figure 11] FIG. 11 is a diagram showing a preferable offset amount when the gap amount of the pair of rectangular wires exceeds the first gap amount and is in a second range up to the second gap amount. [Figure 12] FIG. 12 is a diagram showing the welding conditions and the welding results when welding a pair of rectangular wires. [Figure 13] FIG. 13 is a flowchart illustrating the operation of a laser processing machine according to one or more embodiments, and a laser welding method for rectangular wires according to one or more embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a laser welder and a laser welding method for flat wires according to one or more embodiments will be described with reference to the accompanying drawings. First, an overall configuration example of a laser processing machine 100 according to one or more embodiments will be described with reference to FIG.

[0011] In FIG. 1, the blue laser oscillator 10 emits a blue laser beam L10 having a wavelength of, for example, 400 nm or more and 460 nm or less. The blue laser beam L10 is shown by a broken line. The blue laser beam L10 is transmitted by a transmission fiber 11 and enters a first housing 41 of the processing head 40. The infrared laser oscillator 20 emits an infrared laser beam L20 having a wavelength of, for example, 1060 nm or more and 1090 nm or less. The infrared laser beam L20 is shown by a solid line. The infrared laser beam L20 is transmitted by a transmission fiber 21 and enters a second housing 42 of the processing head 40. The infrared laser oscillator 20 can be configured by a fiber laser oscillator.

[0012] In the processing head 40, a first housing 41 and a second housing 42 are connected by a connecting portion 43. A collimating lens 411 and a bend mirror 412 are stored in the first housing 41. A collimating lens 421, a dichroic mirror 423, a focusing lens 424, and a protective glass 425 are stored in the second housing 42. The collimating lens 411 converts the diverging blue laser beam L10 into collimated light, and the bend mirror 412 reflects the collimated blue laser beam L10 and makes it incident on the dichroic mirror 423. The collimating lens 421 converts the diverging infrared laser beam L20 into collimated light and makes it incident on the dichroic mirror 423.

[0013] The dichroic mirror 423 reflects the blue laser beam L10 and transmits the infrared laser beam L20, thereby emitting a superimposed laser beam in which the blue laser beam L10 and the infrared laser beam L20 are superimposed on each other. The focusing lens 424 focuses the superimposed laser beam and irradiates the pair of rectangular wires 71 and 72 to be welded through a protective glass 425. Although not shown in FIG. 1, a nozzle is attached to the processing head 40, and the superimposed laser beam is irradiated to the rectangular wires 71 and 72 through an opening formed in the nozzle.

[0014] The rectangular wires 71 and 72 are both ends of a segment coil made of copper. The rectangular wire 71 is a first rectangular wire, and the rectangular wire 72 is a second rectangular wire. The collimator lens 421 may be configured to be freely movable in the optical axis direction of the infrared laser beam L20 by a collimator lens drive motor 422.

[0015] The NC device 30 controls the emission of the blue laser beam L10 by the blue laser oscillator 10 and the emission of the infrared laser beam L20 by the infrared laser oscillator 20. The NC device 30 controls the movement of the collimator lens 421 by the collimator lens drive motor 422. The processing head 40 is configured to be freely moved by the moving mechanism 60 in five axial directions, i.e., x, y, z directions, rotation direction, and tilt direction, which are orthogonal to each other in a plane orthogonal to the traveling direction of the superimposed laser beam. The NC device 30 controls the movement of the processing head 40 by the moving mechanism 60. As described later, the NC device 30 controls the irradiation position of the laser beam irradiated to the rectangular wires 71 and 72 and the movement of the laser beam so as to weld the rectangular wires 71 and 72. The NC device 30 is an example of a control device that controls each part of the laser processing machine 100.

[0016] A camera 50 is attached to, for example, the side of the processing head 40. The camera 50 supplies the photographed images of the rectangular wires 71 and 72 to the NC device 30. When the camera 50 photographs the rectangular wires 71 and 72, the NC device 30 positions the camera 50 directly above the rectangular wires 71 and 72, and when the rectangular wires 71 and 72 are welded by the superimposed laser beam emitted from the processing head 40, the NC device 30 controls the moving mechanism 60 to position the second storage body 42 directly above the rectangular wires 71 and 72.

[0017] A camera may be placed above the laser processing machine 100, such as on the ceiling of the installation location of the laser processing machine 100, to photograph the rectangular wires 71 and 72. The rectangular wires 71 and 72 may be photographed by both the camera 50 attached to the processing head 40 and the camera placed above the laser processing machine 100.

[0018] 1 shows only one pair of rectangular wires 71 and 72, but multiple pairs of rectangular wires 71 and 72 may be arranged, and the laser processing machine 100 may weld each pair of rectangular wires 71 and 72 in sequence. This type of welding of rectangular wires 71 and 72 is called hairpin welding.

[0019] The laser processing machine 100 may include a galvanometer scanner 80 for displacing the superimposed laser beam between the dichroic mirror 423 and the focusing lens 424 in the second housing 42, as shown in FIG. 2. The galvanometer scanner 80 includes a first galvanometer mirror 81, a first galvanometer motor 82 for driving the first galvanometer mirror 81, a second galvanometer mirror 83, and a second galvanometer motor 84 for driving the second galvanometer mirror 83. The superimposed laser beam is incident on the first galvanometer mirror 81, reflected, and incident on the second galvanometer mirror 83. The superimposed laser beam is reflected by the second galvanometer mirror 83, and incident on the focusing lens 424.

[0020] The NC device 30 controls the first galvanometer motor 82 and the second galvanometer motor 84 to rotate the first galvanometer mirror 81 and the second galvanometer mirror 83 within a predetermined angle range. By rotating either the first galvanometer mirror 81 or the second galvanometer mirror 83, or both the first galvanometer mirror 81 and the second galvanometer mirror 83, the positions of the superimposed laser beams irradiated to the rectangular wires 71 and 72 can be moved even when the processing head 40 is stopped.

[0021] In FIG. 1, a shielding gas jet nozzle for jetting a shielding gas onto the rectangular wires 71 and 72 when the rectangular wires 71 and 72 are welded, and a shielding gas supply device for supplying a shielding gas to the shielding gas jet nozzle are not shown.

[0022] In the laser processing machine 100 shown in FIG. 1, a blue laser oscillator 10 is provided and a blue laser beam L10 is used to weld the rectangular wires 71 and 72, but the rectangular wires 71 and 72 may be welded using only the infrared laser beam L20 emitted from the infrared laser oscillator 20. The laser beam used to weld the rectangular wires 71 and 72 is not limited to the superimposed laser beam, and may be the infrared laser beam L20. The rectangular wires 71 and 72 are made of copper, and the light absorption rate when the laser beam is irradiated to copper is higher for the blue laser beam L10 than for the infrared laser beam L20. Therefore, when the superimposed laser beam is used, the workability when welding the rectangular wires 71 and 72 can be improved. Furthermore, the rectangular wires 71 and 72 may be welded using only the blue laser beam L10. The laser beam described later is the superimposed laser beam, the infrared laser beam L20, or the blue laser beam L10.

[0023] Next, based on the verification results by the inventor, how to irradiate the flat wires 71 and 72 with a laser beam to weld the flat wires 71 and 72 without welding defects will be described. FIG. 3 shows the state in which the flat wires 71 and 72 are in contact with each other. The sides of the flat wires 71 and 72 facing each other at the tip surfaces of the adjacent flat wires 71 and 72 are respectively side S1 (first side) and side S2 (second side). The side opposite side of the flat wire 71 from side S1 is side S3 (third side), and the side opposite side of the flat wire 72 from side S2 is side S4. In FIG. 3, the dimension X, which is the length of the sides S1 to S4, is, for example, 2.7 mm, and the dimension Y, which is the length of the sides S5 and S6 perpendicular to the sides S1 to S4 of the flat wires 71 and 72, is, for example, 4.7 mm.

[0024] FIG. 4 shows the state where the rectangular wire 71 and the rectangular wire 72 are separated by a gap G. Before welding the rectangular wires 71 and 72, the enamel coating applied to the tips of the rectangular wires 71 and 72 is removed. Therefore, a gap may occur between the tips of the rectangular wires 71 and 72. In FIG. 4, the distance between the sides S3 and S4 is dimension Y+G. As shown in FIG. 3, the sides S1 and S2 of the adjacent rectangular wires 71 and 72 may contact each other and the gap G may be 0 mm, or as shown in FIG. 4, there may be a gap G between the sides S1 and S2 that exceeds 0 mm. The gap G may be up to about 1 mm.

[0025] Fig. 5 shows a first comparative example, in which a beam spot Bs of a laser beam is positioned between sides S1 and S2, and fixed-point irradiation is shown in which the beam spot Bs does not move. The position where the laser beam is irradiated is the center of sides S1 and S2. Figs. 5 to 8 show an example in which the gap amount G is 0 mm.

[0026] FIG. 6 shows a second comparative example, in which the beam spot Bs is positioned on the side S3 with the processing head 40 stopped before the beam spot Bs is irradiated on the side S3, and the beam spot Bs is moved by the processing distance L0 as the processing distance L until it reaches the middle part of the tip surface of the rectangular wire 72. The middle part is the area on the tip surface of the rectangular wire 72 that is closer to the side S4 than the side S2 and closer to the side S2 than the side S4. In FIG. 6, the NC device 30 moves the processing head 40 so that the beam spot Bs moves to the middle part of the tip surface of the rectangular wire 72, and then stops the processing head 40. The position where the laser beam starts to be irradiated is the center of the side S3.

[0027] FIG. 7 shows a third comparative example, in which the NC device 30 moves the processing head 40, which is stopped at a position away from the side S3, toward the side S3, starts irradiating the laser beam so that the beam spot Bs is located on the side S3, and moves the beam spot Bs by the processing distance L0 until it reaches the middle part of the tip surface of the rectangular wire 72. The position where the laser beam irradiation starts is the center of the side S3. The dashed arrow indicates that the processing head 40 is moving without irradiating the laser beam. In FIG. 7, the NC device 30 moves the processing head 40 so that the beam spot Bs moves to the middle part of the tip surface of the rectangular wire 72, then stops irradiating the laser beam, and gradually slows down the moving speed of the processing head 40 until it stops.

[0028] Fig. 8 shows one or more embodiments of the laser welding method for flat wires when the gap amount G is 0 mm. Fig. 8 shows a state in which the processing head 40 is stopped before the beam spot Bs is irradiated onto the side S3, the laser beam irradiation is started, the beam spot Bs is positioned on the side S3, and the beam spot Bs is moved by the processing distance L0 as the processing distance L until it reaches the middle part of the tip surface of the flat wire 72. The position where the laser beam irradiation starts is the center part of the side S3.

[0029] In Fig. 8, the NC device 30 controls the blue laser oscillator 10 and the infrared laser oscillator 20 to emit light, and at the same time controls the moving mechanism 60 to move the laser beam along a moving direction perpendicular to the sides S1 and S3. The NC device 30 stops the irradiation of the laser beam after moving the processing head 40 to move the beam spot Bs to the middle part of the tip surface of the rectangular wire 72, and gradually slows down the moving speed of the processing head 40 until it stops. The center C(0,0) of the dimension Y when the gap amount G is 0 mm, and the center C(0,0) of the dimension Y+G when the gap amount G described later is a value exceeding 0 mm are referred to as reference positions.

[0030] In the fixed-point irradiation shown in Fig. 5, as shown in Fig. 9A, the corners 71e and 72e of the rectangular wires 71 and 72 are likely to remain, and the molten part 73 formed by melting the tips of the rectangular wires 71 and 72 is small. A state in which at least one corner 71e of the rectangular wire 71 remains, or at least one corner 72e of the rectangular wire 72 remains, is referred to as an edge residue welding defect. If the laser beam is irradiated at a fixed point for a long time to prevent the edge residue from occurring, as shown in Fig. 9B, the molten part 73 will expand excessively and the molten width Mw will become too wide, resulting in a welding defect.

[0031] In the irradiation method shown in Fig. 6, as shown in Fig. 9C, welding defects in which the molten part 73 is biased toward the side where the laser beam irradiation starts or ends tend to occur. If the molten part 73 is biased to one side, edge residues tend to occur. In the irradiation method shown in Fig. 7, welding defects in which the molten part 73 is biased tend not to occur, but since the irradiation of the laser beam starts on side S3 while the processing head 40 is moving, edge residues may occur on the side where the laser beam irradiation starts.

[0032] In the irradiation method shown in Fig. 8, edge residue as shown in Fig. 9A hardly occurs, the fusion width Mw of the fusion zone 73 as shown in Fig. 9B does not become too wide, and the bias (melting bias) of the fusion zone 73 as shown in Fig. 9C hardly occurs. Thus, the inventors have verified that the irradiation method shown in Fig. 8 hardly causes the welding defects shown in Figs. 9A to 9C.

[0033] The processing distance L0 in FIG. 8 is the reference processing distance L0. When the gap amount G is 0 mm, the center of the side S3 on the tip surface of the rectangular wire 71 is the irradiation start position where the laser beam irradiation starts. Of the reference processing distance L0, the processing distance from the laser beam irradiation start position to the center C (0,0) is L01, and the processing distance from the center C (0,0) to the laser beam irradiation stop is L02. The moving speed of the laser beam, that is, the welding speed of the rectangular wires 71 and 72 is the reference welding speed V0. As shown in FIG. 8, when the stopped processing head 40 starts moving, the processing head 40 immediately reaches the reference welding speed V0 and moves at the reference welding speed V0 until the laser beam irradiation is stopped. The welding method in which the irradiation start position is on the side S3 of the rectangular wire 71 and the rectangular wires 71 and 72 are welded at the reference processing distance L0 and the reference welding speed V0 is referred to as the reference welding method.

[0034] Further verification by the present inventor has revealed that some conditions in the standard welding method may need to be different between the case where the sides S1 and S2 of the rectangular wires 71 and 72 are in contact with each other and the gap amount G is 0 mm as shown in FIG. 3 and the case where the gap amount G exceeds 0 mm as shown in FIG. 4. The NC device 30 measures the gap amount G between the sides S1 and S3 based on the images of the rectangular wires 71 and 72 captured by the camera 50. The NC device 30 and the camera 50 are examples of sensors that measure the gap amount G between the sides S1 and S3. Other sensors such as a profile sensor may be used as the sensor that measures the gap amount G. The method of measuring the gap amount G is not limited.

[0035] If the gap amount G is 0 mm, the standard welding method is used as described above. If the gap amount G is in the first range R1 up to the first gap amount exceeding 0 mm, as shown in Fig. 10, it is preferable to set the position offset from the center of the side S3 at the tip surface of the rectangular wire 71 toward the rectangular wire 72 by 1 / 2 of the gap amount G as the irradiation start position for starting the irradiation of the laser beam. G / 2 is referred to as the first offset amount.

[0036] In the first range R1, the position offset by the first offset amount G / 2 from the center of the side S3 on the tip surface of the rectangular wire 71 is set as the irradiation start position where the laser beam irradiation begins, and the processing distance L is set as the reference processing distance L0. The processing distance from the laser beam irradiation start position to the center C(0,0) is L01, and the processing distance from the center C(0,0) to the end of the laser beam irradiation is L02. In the first range R1, the welding speed of the rectangular wires 71 and 72 is set to the reference welding speed V0, which is the same as when the gap amount G is 0 mm.

[0037] If the gap amount G is in the second range R2 from the first gap amount to the second gap amount, the position offset by a predetermined offset amount Os toward the rectangular wire 72 in addition to the first offset amount G / 2 should be set as the irradiation start position for starting the irradiation of the laser beam, as shown in Fig. 11. The offset amount Os is referred to as the second offset amount.

[0038] In the second range R2, the position offset from the center of the side S3 on the tip surface of the rectangular wire 71 by the distance obtained by adding the first offset amount G / 2 and the second offset amount is set as the irradiation start position where the irradiation of the laser beam starts, and the processing distance L is set as the reference processing distance L0. The processing distance from the irradiation start position of the laser beam to the center C(0,0) is L01', which is shorter than L01, and the processing distance from the center C(0,0) to the end of the irradiation of the laser beam is L02', which is longer than L02. In the second range R2, the welding speed of the rectangular wires 71 and 72 is set to the reference welding speed V0, which is the same as when the gap amount G is 0 mm.

[0039] If the gap amount is in the third range R3 exceeding the second gap amount, the irradiation start position for starting irradiation of the laser beam should be a position offset by the first offset amount G / 2 from the center of the side S3 on the tip surface of the rectangular wire 71. Also, if it is in the third range R3, it is preferable to set the processing distance L longer than the reference processing distance L0 and the welding speed faster than the reference welding speed V0.

[0040] FIG. 12 shows detailed welding conditions and welding results when the gap amount G is 0 mm, and in the first range R1, the second range R2, and the third range R3. In FIG. 12, the range surrounded by a thick solid line shows welding conditions that are different from the welding conditions in the standard welding method. In the first range R1, the gap amount G is more than 0 mm and 0.1 mm or less, in the second range R2, the gap amount G is more than 0.1 mm and 0.6 mm or less, and in the third range R3, the gap amount G is more than 0.6 mm and 1.0 mm or less. In the example shown in FIG. 12, the gap amount G of 0.1 mm is the first gap amount, and the gap amount G of 0.6 mm is the second gap amount. In FIG. 12, only two gap amounts, 0.8 mm and 1.0 mm, are shown as examples of the gap amount G in the third range R3.

[0041] The processing distance L is set to 0.8Y as the reference processing distance L0. The welding speed is set to 2 m / min as the reference welding speed V0. The welding conditions other than those shown in Fig. 12 are the laser output of the blue laser oscillator 10 is 1800 W, the laser output of the infrared laser oscillator 20 is 1250 W, and the shielding gas is nitrogen at 50 L / min.

[0042] When the gap amount G is 0 mm, the NC device 30 controls the laser processing machine 100 to set the first offset amount to 0 mm and the second offset amount to 0 mm, i.e., to start irradiating the laser beam on the side S3 of the rectangular wire 71, and to weld the rectangular wires 71 and 72 by the reference processing distance L0 at the reference welding speed V0. As a result, when the gap amount G is 0 mm, no edge residue occurs, the fusion width Mw does not become wider at 2.97 mm, and no fusion bias occurs. The irradiation time of the laser beam is 0.118 s.

[0043] In the first range R1, the NC device 30 sets the first offset amount to G / 2 and the second offset amount to 0 mm, that is, the position offset by a distance of G / 2 from the side S3 of the rectangular wire 71 as the laser beam irradiation start position. In addition, the NC device 30 controls the laser processing machine 100 so that the rectangular wires 71 and 72 are welded by a reference processing distance L0 at a reference welding speed V0 in the first range R1. If the gap amount G is 0.1 mm, the first offset amount is 0.05 mm. As a result, when the gap amount G is greater than 0 mm and is 0.1 mm or less, no edge residue occurs, the melting width Mw is not so wide as 3.03 mm, and no melting bias occurs. The laser beam irradiation time is 0.118 s.

[0044] In the second range R2, the NC device 30 sets the first offset amount to G / 2, and if the gap amount G is 0.2 mm, the second offset amount to 0.2 mm, and if the gap amount G is 0.3 to 0.6 mm, the second offset amount to 0.3 mm. In the second range R2, the NC device 30 sets the position offset by the distance obtained by adding the first offset amount and the second offset amount from the side S3 of the rectangular wire 71 as the laser beam irradiation start position, and controls the laser processing machine 100 to weld the rectangular wires 71 and 72 by the reference processing distance L0 at the reference welding speed V0. As a result, in the second range R2, no edge residue is generated, and the fusion width Mw is not so wide, being 3.06 mm, 3.19 mm, 3.14 mm, and 3.15 mm, respectively, when the gap amount G is 0.2 mm to 0.6 mm, and no fusion bias occurs.

[0045] In the third range R3, the NC device 30 sets the first offset amount to G / 2 and the second offset amount to 0 mm, that is, the position offset by the distance of G / 2 from the side S3 of the rectangular wire 71 as the laser beam irradiation start position. In addition, in the third range R3, the NC device 30 controls the laser processing machine 100 to weld the rectangular wires 71 and 72 at a welding speed faster than the reference welding speed V0 by a processing distance L longer than the reference processing distance L0. In the example shown in FIG. 12, if the gap amount G is 0.8 mm, the processing distance L is 0.95Y and the welding speed is 2.2 m / min, and if the gap amount G is 1.0 mm, the processing distance L is 1.0Y and the welding speed is 2.2 m / min.

[0046] As a result, in the third range R3, no edge residue occurs, the melt width Mw is not so wide (3.16 mm when the gap amount G is 0.8 mm, and 3.10 mm when the gap amount G is 1.0 mm), and no melting bias occurs. The irradiation time of the laser beam is 0.128 s when the gap amount G is 0.8 mm, and 0.134 s when the gap amount G is 1.0 mm.

[0047] In the second range R2 where the gap amount G is wider than the first range R1, let us suppose that the laser beam is irradiated to the rectangular wires 71 and 72 from a position offset by the first offset amount G / 2 from the side S3 of the rectangular wire 71 as the irradiation start position of the laser beam. Then, edge residue is likely to occur on the end side of the irradiation of the laser beam. Therefore, by setting the irradiation start position for starting the irradiation of the laser beam to a position offset by the distance obtained by adding a second offset amount exceeding 0 mm to the first offset amount, it is possible to prevent edge residue from occurring on the end side of the irradiation of the laser beam.

[0048] In the third range R3 where the gap amount G is wider than the second range R2, let us suppose that the position offset by the distance obtained by adding the second offset amount exceeding 0 mm to the first offset amount is set as the irradiation start position for starting the irradiation of the laser beam, and the rectangular wires 71 and 72 are irradiated with the laser beam. In order to prevent edge residue from occurring on the end side of the irradiation of the laser beam, the second offset amount must be set to a distance longer than that in the second range R2. This makes it easier for edge residue to occur on the start side of the irradiation of the laser beam.

[0049] Therefore, in the third range R3, the first offset amount is set to G / 2, the second offset amount is set to 0 mm, i.e., the position offset by a distance of G / 2 from the side S3 of the rectangular wire 71 is set as the laser beam irradiation start position, and the processing distance L is set to be longer than the standard processing distance L0. If the welding speed remains at the standard welding speed V0 even though the processing distance L is set to be longer than the standard processing distance L0, the heat input to the rectangular wires 71 and 72 increases, and the fusion width Mw may become too wide. Therefore, in the third range R3, the welding speed is set to a speed faster than the standard welding speed V0.

[0050] In this way, the laser processing machine 100 measures the gap amount G between the side S1 and the side S3, and classifies the gap amount G into 0 mm, the first range R1, the second range R2, and the third range R3. If the gap amount G is 0 mm, the laser processing machine 100 controls the laser processing machine 100 so that the side S3 of the rectangular wire 71 is set as the irradiation start position of the laser beam, and the rectangular wires 71 and 72 are welded by the standard welding method with the standard processing distance L0 and the standard welding speed V0. In the first range R1, the laser processing machine 100 offsets the irradiation start position by the first offset amount, and controls the laser processing machine 100 so that the rectangular wires 71 and 72 are welded by the standard processing distance L0 at the standard processing distance L0 and the standard welding speed V0.

[0051] In the second range R2, the laser processing machine 100 offsets the irradiation start position by the first offset amount and the second offset amount, and controls the laser processing machine 100 so that the rectangular wires 71 and 72 are welded by the reference processing distance L0 at the reference welding speed V0. In the third range R3, the laser processing machine 100 offsets the irradiation start position by the first offset amount, sets the processing distance L longer than the reference processing distance L0, and controls the laser processing machine 100 so that the rectangular wires 71 and 72 are welded by setting the welding speed faster than the reference welding speed V0.

[0052] The first gap amount of 0.1 mm, the second gap amount of 0.6 mm, the reference processing distance L0 of 0.8Y, the reference welding speed V0 of 2 m / min, the first range R1, the second range R2, and the third range R3 shown in Fig. 12 are merely examples. The welding conditions under which no welding defects occur differ depending on whether the laser processing machine 100 is equipped with both the blue laser oscillator 10 and the infrared laser oscillator 20, whether it is equipped with only the infrared laser oscillator 20, or whether it is equipped with only the blue laser oscillator 10.

[0053] When the laser processing machine 100 is equipped with both the blue laser oscillator 10 and the infrared laser oscillator 20, the welding conditions under which no welding defects occur differ depending on the laser output of the blue laser oscillator 10, the laser output of the infrared laser oscillator 20, and the shielding gas conditions. When the laser processing machine 100 is equipped with only the infrared laser oscillator 20, the welding conditions under which no welding defects occur differ depending on the laser output of the infrared laser oscillator 20 and the shielding gas conditions. When the laser processing machine 100 is equipped with only the blue laser oscillator 10, the welding conditions under which no welding defects occur differ depending on the laser output of the blue laser oscillator 10 and the shielding gas conditions. Furthermore, in either case, the welding conditions under which no welding defects occur differ depending on the beam diameter of the laser beam.

[0054] Depending on such various conditions, the range of the gap amount G from 0 mm to an upper limit value of, for example, 1.0 mm may be divided into a case where the gap amount G is 0 mm and a first range R1, a second range R2, and a third range R3 where the gap amount G exceeds 0 mm so as to prevent welding defects. Depending on various conditions, the reference machining distance L0, the reference welding speed V0, the second offset amount in the second range R2, the degree of extension of the machining distance L in the third range R3, and the degree of increase in the welding speed may be set so as to prevent welding defects.

[0055] 12, the gap amount G of 0.1 mm in the first range R1 may be one of the multiple gap amounts G included in the first range R1, or may be the only gap amount G included in the first range R1. In the example shown in Fig. 12, in the second range R2, the second offset amount is 0.2 mm only when the gap amount G is 0.2 mm, and the second offset amount is 0.3 mm for the other gap amounts G. The second offset amount may be a uniform value for all gap amounts G in the second range R2, or may be three or more values.

[0056] The operation of the laser processing machine 100 and the laser welding method executed by the laser processing machine 100 will be described with reference to the flow chart shown in Fig. 13. In Fig. 13, when the laser processing machine 100 starts operating and the processing of the NC device 30 starts, the NC device 30 measures the gap amount G between the pair of rectangular wires 71 and 72 in step S1. In step S2, the NC device 30 determines whether the gap amount G is 0 mm. If the gap amount G is 0 mm (YES), in step S3, the NC device 30 sets the first and second offset amounts to 0, the processing distance L to the reference processing distance L0, and the welding speed to the reference welding speed V0, and proceeds to step S9.

[0057] If the gap amount G is not 0 mm in step S2, the NC device 30 determines in step S4 whether the gap amount G is equal to or less than the first gap amount. If the gap amount G is equal to or less than the first gap amount (YES), the NC device 30 sets the first offset amount to G / 2, the second offset amount to 0, the machining distance L to the reference machining distance L0, and the welding speed to the reference welding speed V0 in step S5, and then proceeds to step S9.

[0058] If the gap amount G is not equal to or less than the first gap amount in step S4 (NO), the NC device 30 determines whether the gap amount G is equal to or less than the second gap amount in step S6. If the gap amount G is equal to or less than the second gap amount (YES), the NC device 30 sets the first offset amount to G / 2 and the second offset amount to a predetermined value for each gap amount G in step S7, sets the processing distance L to a reference distance L0, and sets the welding speed to a reference speed V0, and proceeds to step S9.

[0059] If the gap amount G is not equal to or less than the second gap amount in step S6 (NO), then in step S8, the NC device 30 sets the first offset amount to G / 2 and the second offset amount to 0. Also, in step S8, the NC device 30 sets the processing distance L to a distance longer than the reference distance L0 for each gap amount G, sets the welding speed to a speed faster than the reference speed V0, and transitions the process to step S9.

[0060] In step S9, the NC device 30 controls the laser processing machine 100 to weld the pair of rectangular wires 71 and 72 with the set offset amount (including 0 mm), processing distance L, and welding speed, and then proceeds to step S10. In step S10, the NC device 30 determines whether or not there is a next pair of rectangular wires 71 and 72. If there is a next pair of rectangular wires 71 and 72 (YES), the NC device 30 repeats the processes from step S1 onwards. If there is not a next pair of rectangular wires 71 and 72 (NO), the NC device 30 ends the process.

[0061] 8 shows an example in which the laser beam irradiated to the rectangular wires 71 and 72 is moved by moving the processing head 40 with the moving mechanism 60. The NC device 30 may stop the processing head 40 and move the laser beam irradiated to the rectangular wires 71 and 72 with the galvano scanner 80.

[0062] The present invention is not limited to one or more of the embodiments described above, and various modifications can be made without departing from the gist of the present invention. [Explanation of symbols]

[0063] 10 Blue laser oscillator 11,21 Transmission fiber 20 Infrared laser oscillator 30 NC unit (control unit) 40 Processing head 41 First storage unit 42 Second storage unit 43 Connecting part 50 Camera 60 Moving mechanism 71,72 Rectangular wire 71e,72e corner 73 Welding section 80 Galvano Scanner 81 First Galvano Mirror 82 First Galvano Motor 83 Second Galvano Mirror 84 Second Galvano Motor 411,421 Collimating Lens 412 Bend Mirror 422 Collimating lens drive motor 423 Dichroic Mirror 424 Focusing Lens 425 Protective Glass S1 Side (First Side) S2 Side (Second Side) S3 Side (third side) Around S4~S6

Claims

1. A sensor for measuring a gap between a first side of the first rectangular wire and a second side of the second rectangular wire, which are opposed to each other at the tip surfaces of the first and second rectangular wires to be welded adjacent to each other; A control device that controls the irradiation position of a laser beam irradiated onto the first and second rectangular wires and the movement of the laser beam to weld the first and second rectangular wires; Equipped with The control device includes: If the gap amount measured by the sensor is 0, the center of the third side of the tip surface of the first rectangular wire opposite to the first side is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to a reference welding speed, and the laser beam is moved a reference processing distance from the irradiation start position along a moving direction perpendicular to the first and third sides to the middle part of the tip surface of the second rectangular wire, thereby welding the first and second rectangular wires; If the gap amount measured by the sensor exceeds 0 and is within a first range up to a first gap amount, a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is a distance of 1 / 2 of the gap amount, is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to the reference welding speed, and the laser beam is moved from the irradiation start position by the reference processing distance along a moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, If the gap amount measured by the sensor is within a second range exceeding the first gap amount and up to a second gap amount, a position offset from the center of the third side toward the second rectangular wire by a distance obtained by adding a first offset amount, which is a distance of 1 / 2 of the gap amount, and a predetermined second offset amount exceeding 0 is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to the reference welding speed, and the laser beam is moved from the irradiation start position by the reference processing distance along a moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, If the gap amount measured by the sensor is within a third range exceeding the second gap amount, a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is a distance of 1 / 2 of the gap amount, is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to a welding speed faster than the reference welding speed, and the laser beam is moved from the irradiation start position along a moving direction perpendicular to the first and third sides by a processing distance longer than the reference processing distance to weld the first and second rectangular wires. Laser welding machine.

2. a laser oscillator that emits the laser beam; A processing head that irradiates the laser beam emitted by the laser oscillator onto the first and second rectangular wires; A moving mechanism that moves the processing head; Further equipped with The control device includes: controlling the laser oscillator to a state in which the laser beam is not emitted, and controlling the movement mechanism to position and stop the processing head at a position where the processing head irradiates the laser beam at the irradiation start position; Controlling the laser oscillator to a state in which the laser beam is emitted and at the same time controlling the moving mechanism to move the laser beam along the moving direction.

2. The laser welder of claim 1.

3. A gap amount between a first side of the first rectangular wire and a second side of the second rectangular wire facing each other at each tip surface of the first and second rectangular wires to be welded adjacent to each other is measured by a sensor; If the gap amount measured by the sensor is 0, the center of the third side of the tip surface of the first rectangular wire opposite to the first side is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to a reference welding speed, and the laser beam is moved a reference processing distance from the irradiation start position along a moving direction perpendicular to the first and third sides to the middle part of the tip surface of the second rectangular wire, thereby welding the first and second rectangular wires; If the gap amount measured by the sensor exceeds 0 and is within a first range up to a first gap amount, a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is a distance of 1 / 2 of the gap amount, is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to the reference welding speed, and the laser beam is moved from the irradiation start position by the reference processing distance along a moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, If the gap amount measured by the sensor is within a second range exceeding the first gap amount and up to a second gap amount, a position offset from the center of the third side toward the second rectangular wire by a distance obtained by adding a first offset amount, which is a distance of 1 / 2 of the gap amount, and a predetermined second offset amount exceeding 0 is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to the reference welding speed, and the laser beam is moved from the irradiation start position by the reference processing distance along a moving direction perpendicular to the first and third sides to weld the first and second rectangular wires, If the gap amount measured by the sensor is within a third range exceeding the second gap amount, a position offset from the center of the third side toward the second rectangular wire by a first offset amount, which is a distance of 1 / 2 of the gap amount, is set as the irradiation start position of the laser beam, the moving speed of the laser beam is set to a welding speed faster than the reference welding speed, and the laser beam is moved from the irradiation start position by a processing distance longer than the reference processing distance along a moving direction perpendicular to the first and third sides, to weld the first and second rectangular wires. Laser welding method for rectangular wire.

4. A laser oscillator is controlled to a state where the laser beam is not emitted, and a processing head is positioned at a position where the processing head irradiates the laser beam to the irradiation start position and stopped; At the same time as controlling the laser oscillator to a state in which the laser beam is emitted, the movement of the processing head is started to move the laser beam along the movement direction. The laser welding method for rectangular wires according to claim 3.

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