JP7585464B2 - Laser welding method and laser welding apparatus - Google Patents

Description

The present invention relates to a laser welding method and a laser welding apparatus.

A method for laser welding multiple metal components such as rectangular wires is known (for example, Patent Document 1).

JP 2018-030155 A

If spatter occurs in this type of welding, it can cause problems such as voids forming in the weld metal, residue adhering to the surrounding area, and the residue forming unnecessary electrical circuits in the surrounding area.

Therefore, one of the objectives of the present invention is to provide an improved new laser welding method and laser welding apparatus that, for example, makes it possible to suppress the generation of spatter.

The laser welding method of the present invention is, for example, a laser welding method for laser welding a first end in a first direction of a first member made of a metallic material and a second end in the first direction of a second member made of a metallic material, and includes the steps of: arranging the first end and the second end so that they are adjacent to each other in a second direction intersecting with the first direction; irradiating at least one of the first end and the second end with a laser beam while scanning the laser beam in a predetermined direction intersecting with the first direction; and solidifying a molten pool formed in a state spanning between the first end and the second end in the step of irradiating the laser beam, and in the step of irradiating the laser beam, changing the irradiation state of the laser beam in the region of the first end or the second end where the laser beam is irradiated depending on the irradiation position of the laser beam.

In the laser welding method, in the process of irradiating the laser light, the power of the irradiated laser light may be changed depending on the irradiation position of the laser light.

In the laser welding method, in the step of irradiating the laser light, a scanning path of the irradiation position of the laser light at the first end or the second end includes a linear scanning section that is scanned in a straight line and a non-linear scanning section that is scanned in a curved or bent manner, and the laser light may be irradiated in the non-linear scanning section with a power lower than the power of the laser light irradiated to at least a portion of the linear scanning section.

In the laser welding method, the linear scanning section includes a first section and a second section scanned in the opposite direction to the first section, and the maximum power of the laser light irradiated in the first section may be the same as the maximum power of the laser light irradiated in the second section.

In the laser welding method, the linear scanning section includes a first section and a second section scanned in the opposite direction to the first section, and the maximum power of the laser light irradiated in the first section and the maximum power of the laser light irradiated in the second section may be different from each other.

In the laser welding method, the second section is a section scanned after the first section, and the maximum value of the power of the laser light irradiated in the second section may be greater than the maximum value of the power of the laser light irradiated in the first section.

In the laser welding method, the second section is a section that is scanned after the first section, and the non-linear scanning section is included between the first section and the second section, and the first section and the second section may be separated from each other.

In the laser welding method, in the process of irradiating the laser light, the scanning path of the irradiation position of the laser light at the first end or the second end may include a power change section in which the power of the irradiated laser light is changed over time as the laser light moves.

In the laser welding method, in the step of irradiating the laser light, the scanning path of the irradiation position of the laser light at the first end or the second end may include a constant power section in which the irradiation position moves while the power of the irradiated laser light is constant.

In the laser welding method, the scanning path may include, as the power change section, a power increase section in which the power of the laser light irradiated increases over time as the irradiation position of the laser light moves immediately after the start of laser light scanning.

In the laser welding method, the scanning path may include, as the power change section, a power reduction section in which the power of the laser light irradiated is reduced over time as the irradiation position of the laser light moves just before the end of the laser light scanning.

In the laser welding method, in the step of irradiating the laser light, a scanning path of the irradiation position of the laser light at the first end or the second end includes a first section scanned linearly and a second section bent at a bend located at the end of the first section and scanned linearly in a direction different from the scanning direction of the first section, and at least one of the first section and the second section may include a third section in which the laser light is irradiated with a lower power the closer the irradiation position is to the bend.

In the laser welding method, in the step of irradiating the laser light, the irradiation state of the laser light may be changed depending on the irradiation position of the laser light so that the difference in the irradiation energy density of the laser light depending on the location in the area where the laser light is irradiated at the first end or the second end is reduced.

In the laser welding method, the laser light may include a first laser light and a second laser light having a wavelength that has a higher absorption rate in the metal material of the first end or the second end than the first laser light.

In the laser welding method, in the process of irradiating the laser light, the power of the first laser light may be changed over time and the power of the second laser light may be kept approximately constant over time.

In the laser welding method, in the step of irradiating the laser light, the scanning path of the laser light irradiation position at the first end or the second end may include a section in which scanning is performed while irradiating only the second laser light before starting irradiation of the first laser light.

The laser welding method of the present invention is, for example, a laser welding method for laser welding a first member made of a metallic material and a second member made of a metallic material, and includes a step of irradiating at least one of the first member and the second member with a laser beam while scanning the laser beam, and a step of solidifying a molten pool formed across the first member and the second member in the step of irradiating the laser beam, and in the step of irradiating the laser beam, the irradiation state of the laser beam is changed depending on the irradiation position of the laser beam.

The laser welding apparatus of the present invention is a laser welding apparatus for laser welding a first end in a first direction of a first member made of a metallic material and a second end in the first direction of a second member made of a metallic material, and is provided with a light source that outputs laser light, and an optical head that irradiates at least one of the first end and the second end with the laser light from the light source while scanning the laser light, and changes the irradiation state of the laser light in the area of the first end or the second end where the laser light is irradiated depending on the irradiation position of the laser light.

The laser welding apparatus includes a control unit that variably controls at least one of the output of the laser light from the light source and the scanning speed of the laser light from the optical head, and a temperature sensor that detects the temperature of the molten pool, and the control unit may execute at least one of control to reduce the output of the laser light from the light source and control to increase the scanning speed as the temperature detected by the temperature sensor increases.

The laser welding apparatus includes a control unit that variably controls at least one of the output of the laser light from the light source and the scanning speed of the laser light from the optical head, and a motion sensor that detects movement of the surface of the molten pool, and the control unit may execute at least one of control to reduce the output of the laser light from the light source and control to increase the scanning speed the greater the movement of the surface detected by the motion sensor.

According to the present invention, it is possible to obtain an improved new laser welding method and laser welding apparatus, which, for example, makes it possible to suppress the generation of spatter.

FIG. 1 is an exemplary schematic configuration diagram of a laser welding apparatus according to an embodiment. FIG. 2 is an exemplary schematic plan view showing an example of the shape of a spot of laser light irradiated onto an object from the laser welding device of the embodiment. FIG. 3 is an exemplary schematic side view of an object of the laser welding method according to the embodiment before welding. FIG. 4 is an exemplary schematic side view of an object after welding according to the laser welding method of the embodiment. FIG. 5 is an exemplary schematic perspective view of a rectangular wire including a member as an object of the laser welding method according to the embodiment. FIG. 6 is an illustrative schematic plan view showing an example of a scanning path at an end portion in the laser welding method according to the embodiment. FIG. 7 is a graph showing an example of a change in light source output depending on the irradiation position in a scanning path in the laser welding method of the embodiment. FIG. 8 is an exemplary schematic plan view showing an example of setting a range in which the light source output is relatively low, which is set near the edge in the laser welding method according to the embodiment. FIG. 9 is an exemplary schematic plan view showing an example of setting a range in which the light source output is relatively low, which is set near the bent portion, in the laser welding method according to the embodiment. FIG. 10 is an illustrative schematic plan view showing another example of a scanning path at an end portion in the laser welding method according to the embodiment. FIG. 11 is an illustrative schematic plan view showing another example of a scanning path at an end portion in the laser welding method according to the embodiment. FIG. 12 is an exemplary schematic plan view showing a plurality of sections included in the scanning path of FIG. FIG. 13 is a graph showing an example of a change over time in the light source output when scanning is performed along the scanning path in FIG. 11 and the section in FIG. FIG. 14 is a graph showing another example of the change over time in the light source output when scanning is performed along the scanning path in FIG. 11 and in the section in FIG. FIG. 15 is an illustrative schematic plan view showing yet another example of a scanning path at an end portion in the laser welding method according to the embodiment.

Below, exemplary embodiments and variants of the present invention are disclosed. The configurations of the embodiments and variants shown below, and the actions and results (effects) brought about by said configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments and variants. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

The following embodiments and variations have similar components. In the following, the similar components are given common reference symbols and duplicate explanations may be omitted.

In addition, in each figure, direction X is represented by arrow X, direction Y is represented by arrow Y, and direction Z is represented by arrow Z. Directions X, Y, and Z intersect with each other and are perpendicular to each other. The Z direction is the direction in which multiple members that constitute the target object W extend. Note that the Z direction is approximately vertically upward, but may be inclined relative to the vertically upward direction.

In addition, in this specification, ordinal numbers are given for convenience to distinguish parts, members, locations, directions, sections, positions, etc., and do not indicate priority or order.

[Overview of laser welding device and laser welding]
Fig. 1 is a diagram showing a schematic configuration of a laser welding apparatus 100 according to an embodiment. As shown in Fig. 1, the laser welding apparatus 100 includes a laser device 110 (111, 112), an optical head 120, an optical fiber 130, a drive mechanism 140, a sensor 150, and a control device 200.

The laser welding device 100 irradiates a laser beam L onto the surface of an object W to be laser welded. The object W is partially melted by the energy of the laser beam L, and then cooled and solidified, thereby welding the object W. The object W has multiple components, and a molten pool is formed across the multiple components by laser welding, and the multiple components are joined by solidifying the molten pool.

Each of the multiple components that make up the target object W can be made of, for example, a copper-based metal material such as copper or a copper alloy, or an aluminum-based metal material such as aluminum or an aluminum alloy. The multiple components may be made of the same metal material, or may be made of different metal materials. Note that the multiple components that make up the target object W may or may not be conductors.

Each of the laser devices 111 and 112 includes a laser oscillator and is configured to output, for example, a single-mode laser beam with a power of several kW. The laser device 110 may be configured to include, for example, multiple semiconductor laser elements therein and to output a multi-mode laser beam with a power of several kW as the total output of the multiple semiconductor laser elements. The laser device 110 may also include various laser light sources such as a fiber laser, a YAG laser, a disk laser, etc. The laser device 110 outputs, for example, a laser beam with a wavelength of 400 nm or more and 1200 nm or less.

The laser device 111 outputs a first laser light having a wavelength of, for example, 800 nm or more and 1200 nm or less. The laser device 111 may also be referred to as a first laser device. The laser oscillator of the laser device 111 is a light source and may also be referred to as a first laser oscillator.

On the other hand, the laser device 112 outputs a second laser light having a wavelength of, for example, 300 nm or more and 600 nm or less. The laser device 112 may also be referred to as a second laser device. The laser oscillator of the laser device 112 is a light source and may also be referred to as a second laser oscillator.

For copper-based and aluminum-based materials, the second laser light has a higher absorption rate and a lower reflectance rate than the first laser light.

In addition, laser devices 111 and 112 may each output a continuous wave of laser light or a pulse of laser light.

The control device 200 can control the operation of the laser devices 111 and 112. For example, the control device 200 can control each of the laser devices 111 and 112 to output laser light, stop outputting laser light, and change the output intensity.

The optical fiber 130 optically connects the laser device 110 and the optical head 120. In other words, the optical fiber 130 guides the laser light output from the laser device 110 to the optical head 120. When the laser device 110 outputs a single mode laser light, the optical fiber 130 is configured to propagate the single mode laser light. In this case, the ^M2 beam quality of the single mode laser light is set to 1.3 or less. The ^M2 beam quality may also be referred to as an M2 factor.

The optical head 120 is an optical device for irradiating the laser light input from the laser device 110 toward the object W. The optical head 120 has a collimating lens 121, a condensing lens 122, a filter 123, a mirror 124, a DOE 125, and a galvano scanner 126. The collimating lens 121, the condensing lens 122, the filter 123, the mirror 124, the DOE 125, and the galvano scanner 126 may also be referred to as optical components.

Each collimating lens 121 collimates the laser light input via the optical fiber 130. The collimated laser light becomes parallel light.

Mirror 124 reflects the first laser light, which has been collimated by the collimator lens 121, and directs it toward the galvanometer scanner 126.

Filter 123 is a high-pass filter that transmits the first laser light and reflects the second laser light. The first laser light from mirror 124 passes through filter 123 and heads toward galvanometer scanner 126. On the other hand, the second laser light from collimator lens 121 is reflected by filter 123 and heads toward galvanometer scanner 126.

The galvano scanner 126 has multiple mirrors 126a and 126b. By changing the angles of the multiple mirrors 126a and 126b, the emission direction of the laser light L from the optical head 120 can be switched, and the irradiation position of the laser light L on the surface of the object W can be changed. The angles of the mirrors 126a and 126b are each changed by, for example, a motor (not shown) controlled by the control device 200. By changing the emission direction of the laser light L while irradiating the laser light L, the laser light L can be scanned on the surface of the object W.

The focusing lens 122 focuses the parallel laser light coming from the galvanometer scanner 126 and irradiates the laser light L (output light) onto the target W.

The DOE 125 (DOE: diffractive optical element) shapes the beam of the first laser light that has been collimated by the collimator lens 121. The DOE 125 is an example of a beam shaper.

The driving mechanism 140 changes the relative position of the optical head 120 with respect to the object W. The driving mechanism 140 has, for example, a rotating mechanism such as a motor, a speed reducing mechanism that reduces the rotation output of the rotating mechanism, and a motion conversion mechanism that converts the rotation reduced by the speed reducing mechanism into linear motion. The control device 200 can control the driving mechanism 140 so that the relative position of the optical head 120 in the X direction, Y direction, and Z direction with respect to the object W changes. The driving mechanism 140 can change (switch) the object W to be laser welded among multiple objects W supported by a support mechanism (not shown). The driving mechanism 140 can also change the irradiation position of the laser light L on the object W. The driving mechanism 140 can also be used to change the irradiation point along with changing the irradiation direction of the laser light on the object W. Furthermore, the driving mechanism 140 can change the irradiation position while the laser light L is irradiated on the surface of the object W. That is, the driving mechanism 140 can scan the laser light L on the surface of the object W.

2 is a plan view of a spot S formed on the end 20a of the object W by irradiating the end 20a with a laser beam L. As shown in FIG. 2, the spot S includes an approximately circular irradiation area IA1 by the beam B1 of the first laser light output from the laser device 111 and an approximately circular irradiation area IA2 by the beam B2 of the second laser light output from the laser device 112. In the example of FIG. 2, the irradiation area IA1 is located within the irradiation area IA2, and the center of the irradiation area IA1 and the center of the irradiation area IA2 are approximately coincident. However, the shape of the spot S is not limited to the example of FIG. 2, and the shapes of the irradiation areas IA1 and IA2 are not limited to a circle. In addition, the beam may be shaped by the DOE 125 so that the irradiation area IA1 includes, for example, a plurality of small areas arranged in a ring or matrix. When the beam shape of the first laser light output from the laser device 111 can be appropriately set by the DOE 125, it may be unnecessary to output the second laser light from the laser device 112. In the spot S, it is sufficient that at least a part of the irradiation area IA2 is located in front of the irradiation area IA1 in the scanning direction, and the center of the irradiation area IA1 and the center of the irradiation area IA2 may be shifted from each other.

Figure 3 is a side view showing the state of the object W before welding. As shown in Figure 3, the object W has two members 20 (21, 22). Both of the two members 20 are made of a metal material. An example of the object W shown in Figure 3 is the connection of the windings of an electromagnetic coil used in a motor of a vehicle or the like by welding them together.

The two members 20 each extend in the Z direction and have Z-direction ends 20a (21a, 22a). The ends 20a extend across the Z direction. That is, the ends 20a extend in both the X and Y directions. The Z direction is an example of a first direction. The ends 21a are an example of a first end, and the ends 22a are an example of a second end.

Prior to welding, the two members 20 are arranged adjacent to each other in the X direction intersecting the Z direction and aligned in the X direction. A gap g is formed between the side surfaces facing each other in the X direction. The size of the gap g is 0 or more. In other words, the two members 20 may be in at least partial contact. The X direction is an example of a second direction.

In the example of Figure 3, end 21a and end 22a are aligned in the X direction and are at the same position in the Z direction, but this is not limited to this, and end 21a and end 22a may be offset in the Z direction.

When welding the object W, i.e., the two members 20, the optical head 120 irradiates the laser light L toward the end 20a. The irradiation direction of the laser light L is the opposite direction to the Z direction or a direction inclined relative to the opposite direction to the Z direction. The laser light L may be irradiated to both the end 21a and the end 22a, or only one of the end 21a and the end 22a.

Figure 4 is a side view showing the state in which a weld 23 (molten pool) is formed on the object W. As shown in Figure 4, the two members 20 are melted at the end 20a by irradiating the end 20a with laser light L, and the weld 23 is formed in a state in which it spans the two ends 20a. The weld 23 is formed by cooling and solidifying the molten pool formed in a state in which it spans between the two ends 20a. The molten pool, which is a fluid metal material, has a shape that bulges in the Z direction due to surface tension. Accordingly, the weld 23, which is the solidified molten pool, also has a shape that bulges in the Z direction. The weld 23 mechanically connects the two members 21 and 22. Furthermore, if the two members 21 and 22 are made of conductive metal, the weld 23 electrically connects the two members 21 and 22.

The sensor 150 (see FIG. 1) is, for example, a camera that captures an image of the molten pool formed on the object W. In this case, the sensor 150 is an example of a motion sensor. The control device 200 can obtain the movement (change over time) of the surface of the molten pool from the image acquired by the sensor 150.

The sensor 150 may also be a thermal camera capable of detecting the temperature of the molten pool. In this case, the sensor 150 is an example of a temperature sensor. The control device 200 can obtain the temperature of the molten pool from the temperature image obtained by the sensor 150.

Figure 5 is a perspective view of a rectangular wire 10 including a member 20. The member 20 is, as an example, the core wire (internal conductor) of the rectangular wire 10 as shown in Figure 5. The rectangular wire 10 has a member 20 and a coating 30 of the member 20. The member 20 is made of a metal material having electrical conductivity. The shape of the cross section of the member 20 perpendicular to the extension direction is approximately rectangular. The coating 30 has insulating properties and is made of, for example, enamel or a synthetic resin material. The coating 30 may have an enamel layer and an extruded resin layer surrounding the enamel layer. The laser welding device 100 is applied to welding the ends 20a of the member 20 as the core wire of such a rectangular wire 10. In this case, the coating 30 is removed near the ends of the two rectangular wires 10 in the extension direction. Then, as shown in FIG. 3 , end portions 20 a of two members 20 arranged adjacent to each other and facing in the same direction (extension direction) are welded by a laser welding device 100 .

The rectangular wire 10 may form a segment coil provided in a rotating electrical device. The laser welding method using the laser welding device 100 of this embodiment can be applied to welding the ends of adjacent segment coils set in a stator core.

However, the member 20 that is the target object W is not limited to the core wire of the rectangular wire 10, but may be any member that extends in the Z direction and is adjacent to each other in the X direction, as shown in Fig. 3. Also, the member 20 may be a plate-like member or a wire material.

[Scanning Path]
Fig. 6 is a plan view showing an example of a scanning path R1 of the laser light L at the ends 21a and 22a. As shown in Fig. 6, in this embodiment, the laser light L scans along the scanning path R1 in a direction intersecting the Z direction.

As shown in FIG. 6, both end 21a and end 22a have a quadrangular shape, and in this embodiment, as an example, end 21a and end 22a have a rectangular shape with sides extending in the X direction and sides extending in the Y direction, and are relatively short in the X direction and relatively long in the Y direction. In this case, the Y direction can be referred to as the longitudinal direction, and the X direction can be referred to as the transverse direction. In the example of FIG. 6, end 21a and end 22a have the same shape, but are not limited to this.

In the example of Figure 6, the laser light L is scanned, for example, in an area A1 that is closer to the end 22a than the center C1 of the end 21a in the X-direction, and an area A2 that is closer to the end 21a than the center C2 of the end 22a in the X-direction.

The scanning path R1 has sections R11, R12, R13, R14, and R15. Here, the scanning path R1 is a continuous linear path that connects the irradiation start point (irradiation position P1) to the irradiation end point (irradiation position P6). Research by the inventors has revealed that a continuous scanning path from the irradiation start point to the irradiation end point can reduce the temperature difference (temperature variation) depending on the location of the end portions 21a, 22a (molten pool) and form a more stable molten pool, compared to a case in which multiple scanning paths spaced apart from each other are provided in a dispersed manner. The irradiation start point can also be referred to as the scanning start position, and the irradiation end point can also be referred to as the scanning end position.

Section R11 is the section from irradiation position P1 to irradiation position P2, and section R12 is the section from irradiation position P2 to irradiation position P3. Note that in FIG. 6, for ease of understanding, sections R11 and R12 are drawn shifted in the X direction, but in reality, sections R11 and R12 overlap, and irradiation position P1 and irradiation position P3 are in the same position.

Irradiation position P1 is the starting point of irradiation. Irradiation position P1 is located near edge 21a1 of end 21a in the opposite Y direction. Irradiation position P2 is located near edge 21a2 of end 21a in the Y direction.

The laser light L is scanned in a section R11 extending linearly in the Y direction, that is, in the longitudinal direction of the end 21a, from the irradiation position P1 to the irradiation position P2. The laser light L scanned in the section R11 is bent in the opposite direction at the irradiation position P2 located at the end of the section R11, that is, turns back, and is scanned in a section R12 extending linearly in the opposite direction of the Y direction from the irradiation position P2 to the irradiation position P3. From the section R11 to the section R12, the section R11 is an example of a first section, the section R12 is an example of a second section, and the irradiation position P2 is an example of a bent section. In addition, the section from the section R11 to the section R12 is an example of a bent scanning section. The angle change amount at the irradiation position P2 as the bent section of the bent scanning section is 180°. In this specification, the angle change amount is a value of 180° or less.

Section R13 is the section from irradiation position P3 to irradiation position P4. Irradiation position P4 is located near the edge 22a2 of the end 22a on the opposite side in the Y direction.

The laser light L scanned in section R12 is bent 90° at irradiation position P3 located at the end of section R12, and is scanned in section R13, which extends linearly from irradiation position P3 to irradiation position P4 in the opposite direction of the X direction, i.e., in the short direction of the ends 21a and 22a. From section R12 to section R13, section R12 is an example of a first section, section R13 is an example of a second section, and irradiation position P3 is an example of a bent portion. In addition, the section from section R12 to section R13 is an example of a bent scanning section. The angle change amount at irradiation position P3 as the bent portion of the bent scanning section is 90°.

Section R14 is the section from irradiation position P4 to irradiation position P5, and section R15 is the section from irradiation position P5 to irradiation position P6. Note that in FIG. 6, for ease of understanding, sections R14 and R15 are drawn shifted in the X direction, but in reality, sections R14 and R15 overlap, and irradiation position P4 and irradiation position P6 are in the same position.

Irradiation position P5 is located near the Y-direction edge 22a2 of end portion 22a. Irradiation position P6 is the end point of irradiation.

The laser light L scanned in section R13 is bent 90° at irradiation position P4 located at the end of section R13, and is scanned in section R14 extending linearly from irradiation position P4 to irradiation position P5 in the Y direction, i.e., in the longitudinal direction of end 22a. From section R13 to section R14, section R13 is an example of a first section, section R14 is an example of a second section, and irradiation position P4 is an example of a bent portion. Furthermore, the section from section R13 to section R14 is an example of a bent scanning section. The angle change amount at irradiation position P4 as the bent portion of the bent scanning section is 90°.

The laser light L scanned in section R14 is bent in the opposite direction at irradiation position P5 located at the end of section R14, i.e., turns back, and is scanned in section R15 that extends linearly in the opposite direction of the Y direction from irradiation position P5 to irradiation position P6. From section R14 to section R15, section R14 is an example of a first section, section R15 is an example of a second section, and irradiation position P5 is an example of a bending section. In addition, the section from section R14 to section R15 is an example of a bending scanning section. The amount of angle change at irradiation position P5 as the bending section of the bending scanning section is 180°.

As is clear from Figure 6, sections R11, R12, R14, and R15 include irradiation positions that are farther from the edges 21a1, 21a2, 22a1, and 22a2 than irradiation positions P1 to P6, which are the ends of each section. Irradiation positions P1 to P6 are examples of irradiation ends.

[Change in light source output depending on irradiation position of scanning path]
The inventors performed welding by scanning the laser light L along the scanning path R1 in FIG. 6. In this experiment, the end portions 21a and 22a, which have a length in the X direction of about 2 [mm] and a length in the Y direction of about 3 [mm], were irradiated with a laser light including a first laser light having a wavelength of 1070 [nm] and a second laser light having a wavelength of 450 [nm]. In a plane intersecting the Z direction of the end portions 21a and 22a, a circular spot (beam) of the first laser light and a circular spot (beam) of the second laser light were arranged concentrically, and the diameter of the spot of the first laser light at the end portions 21a and 22a was set to about 15 [μm], and the diameter of the spot of the second laser light was set to about 230 [μm]. The diameter of the spot can be defined as the diameter of a region including the peak of the beam and having an intensity of 1/e2 or ^more of the peak intensity. In the case of a non-circular beam, the length of the region having an intensity of 1/ ^e2 or more of the peak intensity in a direction perpendicular to the scanning direction can be defined as the beam diameter. Moreover, the power distribution in the spot is not limited to a Gaussian shape. The scanning speed of the laser light L was constant at 80 mm/s.

The inventors conducted experiments under the above conditions and found that spatters occurred more frequently at irradiation positions close to the longitudinal edges 21a1, 21a2, 22a1, and 22a2, such as irradiation positions P1 to P6, than at irradiation positions farther from these edges 21a1, 21a2, 22a1, and 22a2. This is presumably because, compared to the intermediate positions in the longitudinal direction, there is less metal material in the vicinity of the longitudinal edges 21a1, 21a2, 22a1, and 22a2, so heat tends to build up and the temperature of the molten pool tends to rise, which in turn increases the frequency of spatters.

Furthermore, if the temperature of the molten pool rises, the molten pool will grow larger, and there is a risk that the molten pool will spill over from the ends 21a, 22a.

Therefore, the inventors conducted repeated experiments and discovered that by appropriately adjusting the output of the laser light according to the irradiation position, it is possible to suppress excessive increases in the temperature of the molten pool and perform suitable welding, for example, by reducing spatter and making it less likely for the molten pool to spill over.

7 is a graph showing an example of the change in the light source output (power) of the first laser light in the scanning path R1 from the irradiation position P1 to the irradiation position P6, i.e., the output of the laser light from the laser device 111, depending on the irradiation position in the scanning path R1. The output of the second laser light was constant at 150 [W].

As shown in FIG. 7, in sections R11, R12, R14, R15, the light source output at intermediate positions Pm1, Pm2, Pm4, Pm5, which are farther from the edges 21a1, 21a2, 22a1, 22a2, is set to the peak of each section R11, R12, R14, R15, and is set higher than the light source output at irradiation positions P1, P2, P4, P5, P6, which are closer to the edges 21a1, 21a2, 22a1, 22a2.

7, between the irradiation position P1 and the intermediate position Pm1 in the section R11, the light source output is set lower the closer to the irradiation position P1, and between the intermediate position Pm1 and the irradiation position P2 in the section R11, the light source output is set lower the closer to the irradiation position P2. Similarly, between the irradiation position P2 and the intermediate position Pm2 in the section R12, between the intermediate position Pm2 and the irradiation position P3 in the section R12, between the irradiation position P4 and the intermediate position Pm4 in the section R14, between the intermediate position Pm4 and the irradiation position P5 in the section R14, between the irradiation position P5 and the intermediate position Pm5 in the section R15, and between the intermediate position Pm5 and the irradiation position P6 in the section R15, the light source output is set lower the closer to the irradiation positions P1 to P6 as the irradiation ends of each section. The sections between the intermediate positions Pm1, Pm2, Pm4, Pm5 and the irradiation positions P1 to P6 adjacent to the intermediate positions Pm1, Pm2, Pm4, Pm5 are an example of a fourth section.

6, the scanning path R1 is bent or turned back at irradiation positions P2 to P5. The inventors' careful study revealed that near such bends, the laser light spot remains in a relatively close range for a long time, and the temperature of the molten pool is more likely to rise compared to sections where the laser light spot moves linearly without bending or turning back, regardless of the distance from the edges 21a1, 21a2, 22a1, and 22a2, which may increase the frequency of spattering.

7, the setting in which the light source output is lower the closer to irradiation positions P2 to P5 as bending portions in scanning path R1 has the effect of suppressing sputtering even when irradiation positions P2 to P5 are far from edges 21a1, 21a2, 22a1, and 22a2. The sections between intermediate positions Pm1, Pm2, Pm4, and Pm5 and irradiation positions P2 to P5 as bending portions adjacent to intermediate positions Pm1, Pm2, Pm4, and Pm5 are an example of a third section.

In other words, the smaller the radius of curvature at the irradiation position of the scanning path R1 in a planar view, the lower the light source output at that irradiation position, thereby suppressing the temperature rise of the molten pool.

In addition, the larger the angle change amount at the bend in the above-mentioned bend scanning section, the more likely the laser light spot will remain in a closer position, and the more likely the temperature of the molten pool will rise. Therefore, by lowering the light source output at the bend as the angle change amount increases, the temperature rise of the molten pool can be suppressed. In the example of FIG. 7, the temporary light source output reduction amount D1 when passing through the irradiation position P2 as the bend in the bend scanning section with an angle change amount of 180° from section R11 to section R12 is greater than the temporary light source output reduction amount D2 when passing through the irradiation position P3 as the bend in the bend scanning section with an angle change amount of 90° from section R12 to section R13.

In addition, in the setting of Figure 7, the light source output gradually changes linearly in each section R11, R12, R14, and R15, but this is not limited to this, and the light source output may be set to be lowered in the range of the scanning path R1 where the temperature of the molten pool is likely to increase.

Figure 8 is a plan view showing an example of a range S3 (hatched area) in which the light source output is relatively low and set near the edge 21a2 and the irradiation position P2, and a range S4 outside the range S3 in which the light source output is relatively high. Range S3 is an example of a third range and a specified area, and may also be referred to as an edge area. Range S4 is an example of a fourth range and another specified area. In this way, the light source output (power) at the irradiation positions included in the range (third range) within a predetermined distance from the edge 21a1, 21a2, 22a1, 22a2 or the irradiation positions P1 to P6 close to the edge 21a1, 21a2, 22a1, 22a2 is set to be lower than the light source output at the irradiation positions included in the range (fourth range) outside the range or when the irradiation position is the center in the Y direction of the members 21 and 22, for example, to be 80% or less, thereby obtaining advantages such as suppressing the occurrence of spatter in the range S3 and suppressing the spilling of the molten pool. The width of the range S3 in the Y direction is preferably 2.4 mm or less, and more preferably 1.8 mm or less. In addition, it is preferable that the ratio of the Y-direction width of range S3 to the Y-direction dimension of member 21 ((Y-direction width of range S3 [mm]) / (Y-direction dimension of member 21 [mm])) is 0.8 or less, and it is even more preferable that it is 0.6 or less.

FIG. 9 is a plan view showing an example of a range S1 (hatched area) in which the light source output is relatively low within a predetermined distance from the irradiation position P3 as a bending portion, and a range S2 in which the light source output is relatively high outside the range S1. The range S1 is an example of a first range and a predetermined area, and the range S2 is an example of a second range and another predetermined area. In this way, by setting the light source output (power) at the irradiation position included in the range (first range) within a predetermined distance from the irradiation positions P2 to P5 as a bending portion to be lower than the light source output at the irradiation position included in the range (second range) outside the range, for example, the occurrence of sputtering in the range S1 can be suppressed. Note that the bending portion can be defined as a region in which the scanning direction of the laser light changes by a predetermined angle (for example, 45 degrees) or more, and the radius of curvature of the scanning trajectory of the laser light is a predetermined value (for example, 1.0 mm) or less.

[Changing the scanning speed depending on the irradiation position of the scanning path]
It can be considered that the change in light source output according to the irradiation position as shown in Figure 7 reduces the location-specific difference (variation) in the laser light irradiation energy per unit area of the ends 21a and 22a, i.e., the irradiation energy density for the ends 21a and 22a.

The lower the scanning speed of the laser light L at the ends 21a and 22a, the higher the irradiation energy density, and the higher the scanning speed, the lower the irradiation energy density. Therefore, for example, at intermediate positions Pm1, Pm2, Pm4, and Pm5, which are relatively far from the edges 21a1, 21a2, 22a1, and 22a2 or the irradiation positions P2 to P5 as the bends, the scanning speed may be relatively slow, and the closer to the edges 21a1, 21a2, 22a1, and 22a2 or the irradiation positions P2 to P5, the higher the scanning speed may be. In this case, if it is difficult to increase the scanning speed at or near the irradiation positions P2 to P5 as the bends, the light source output may be lowered.

That is, the lower the scanning speed, the lower the light source output may be. According to such a setting, the increase in the irradiation energy density due to the lower scanning speed can be suppressed by lowering the light source output. Conversely, the higher the light source output, the higher the scanning speed may be. In addition, the light source output may be lowered when the scanning speed of the laser light is equal to or lower than a predetermined value, more preferably by 50% or more. As an example, when the scanning speed is equal to or lower than 50 mm/sec, which is half of the initial scanning speed of 100 mm/sec, the light source output may be lowered. In this case, the predetermined value is half the value of the initial scanning speed, and may also be referred to as the threshold speed. According to such a setting, the increase in the irradiation energy density due to the higher light source output can be suppressed by increasing the scanning speed. The scanning speed is an example of the irradiation state of the laser light.

Furthermore, it is preferable for the cross-sectional area of the target object W perpendicular to the irradiation direction of the laser light to be 30 mm ² or less, more preferably 20 mm ² or less, and even more preferably 10 mm ² or less, since this can effectively prevent an increase in the frequency of spattering and the molten pool from spilling over the ends 21a, 22a.

[Other control examples]
At the start of scanning, the temperature of the ends 21a, 22a increases at a slower rate than after the start of scanning. However, if the light source output of the first laser beam is increased, keyholes may be generated, causing localized temperature increases, making the molten pool unstable and causing spatters. Therefore, the light source output of the second laser beam at the irradiation position P1 may be set higher than the light source output of the second laser beam after the start of scanning. With this setting, the temperature of the ends 21a, 22a can be increased more slowly by irradiating the second laser beam, which has a higher absorptivity, and the molten pool can be formed more stably, thereby suppressing the occurrence of spatters.

The control device 200 may also obtain the amount of movement (amplitude) of the surface of the molten pool from the image acquired by the sensor 150, and when the amount of movement becomes large, the control device 200 may lower the light source output of the laser light L or increase the scanning speed of the laser light L so that the irradiation energy density is reduced. Specifically, for example, the control device 200 can control the laser device 110 to lower the light source output when the amount of movement exceeds a threshold, or to lower the light source output as the amount of movement becomes larger. The control device can also control the galvano scanner 126 and the drive mechanism 140 to increase the scanning speed when the amount of movement exceeds a threshold, or to increase the scanning speed as the amount of movement becomes larger. Such control can further stabilize the molten pool, and thus suppress the occurrence of spatter.

Furthermore, the control device 200 can obtain the temperature of the molten pool from the image obtained by the sensor 150, and based on the temperature of the molten pool, for example, control the irradiation state of the laser light according to the irradiation position, that is, the light source output and the scanning speed, so that the temperature of the molten pool falls within a predetermined range. Specifically, for example, the control device 200 can control the laser device 110 to lower the light source output when the temperature exceeds a threshold value, or to lower the light source output as the temperature increases. In addition, the control device can increase the scanning speed when the temperature exceeds a threshold value, or to increase the scanning speed as the temperature increases, by controlling the galvanometer scanner 126 and the driving mechanism 140. Such control can further stabilize the molten pool, and thus suppress the occurrence of spatters. The sensor 150 may detect the state of the radiation light output from the molten pool. In this case, the state of the radiation light that changes according to the temperature of the molten pool and can be detected by the sensor 150 includes, for example, intensity and wavelength. The control device 200 obtains the temperature of the molten pool from the detection value of the sensor 150 based on the correlation between the detection value and the temperature, and can control the irradiation state of the laser light, i.e., the light source output and scanning speed, according to the irradiation position so that the temperature of the molten pool falls within a predetermined range, for example.

[Another example of a scanning path]
10 is a plan view showing an example of a scanning path R2 of the laser light L at the ends 21a and 22a. In the example of FIG. 10, the laser light L is scanned along the scanning path R2 in a direction intersecting the Z direction. The scanning path R2 includes a section R21 extending in the Y direction from an irradiation position P1 close to the edge 21a1 on the end 21a to an irradiation position P2 close to the edge 21a2, a section R22 extending in the opposite direction in the X direction from the irradiation position P2 to an irradiation position P3 close to the edge 22a2 on the end 22a, a section R23 extending in the opposite direction in the Y direction from the irradiation position P3 to an irradiation position P4 close to the edge 22a1, and a section R24 extending in the X direction from the irradiation position P4 to an irradiation position P4 that is the same position as the irradiation position P1. In this example, the irradiation positions P2, P3, and P4 are bent portions with an angle change of 90°. In this case too, by lowering the light source output and increasing the scanning speed closer to the irradiation positions P1 to P4, the difference (variation) in irradiation energy density depending on the location of the ends 21a, 22a is reduced, thereby suppressing the occurrence of spattering due to excessive temperature rise in the molten pool and the spilling of the molten pool.

[Another example of changing the light source output depending on the irradiation position of the scanning path]
FIG. 11 is a plan view showing an example of a scanning path R100 of the laser light L at the ends 21a and 22a. In the example of FIG. 11, the spot S of the laser light L (see FIG. 2) moves (scans) along the scanning path R100 in a direction intersecting the Z direction. The scanning path R100 shows the movement trajectory of the center of the spot S. The laser light L is scanned in a substantially U-shape on the end 21a, and then scanned in a substantially U-shape on the end 22a. At both ends 21a and 22a, the scanning path R100 is set within the regions A1 and A2. The shape of the scanning path R100 on the end 21a and the shape of the scanning path R100 on the end 22a are substantially the same. In addition, the laser light L is not irradiated from the optical head 120 on the movement path T between the ends 21a and 22a.

12 is a plan view of the scanning path R100 of the laser light L at each end 21a, 22a. Note that in FIG. 12, the scanning path R100 is drawn with a width for ease of understanding, but the width of the scanning path R100 in FIG. 12 is unrelated to the size of the spot S.

As shown in FIG. 12, scanning path R100 includes sections R101 to R109 in this order. Spot S moves linearly in the Y direction in sections R101 to R105. Next, spot S moves while bending in an approximately U-shape that opens in the opposite direction of the Y direction in section R106. Next, spot S moves linearly in the opposite direction of the Y direction in sections R107 to R109. In the example of FIG. 12, sections R101 to R105 and sections R107 to R109 are examples of linear scanning sections, and section R106 is an example of a non-linear scanning section. Additionally, sections R101 to R105 are an example of a first section, and sections R107 to R109 are an example of a second section.

In the example of Figure 12, sections R101-R105 and sections R107-R109 are spaced apart from each other in the X direction, and section R106 is smoothly connected to sections R101-R105 and sections R107-R109 and is curved at a predetermined radius. The curvature radius of section R106 is half the distance in the X direction between sections R101-R105 and sections R107-R109. By setting the scanning path R100 in this way, it is possible to reduce the irradiation energy density in section R106 compared to when section R106 is turned back in the opposite direction (180°) in a straight line, which may further suppress the occurrence of spattering due to excessive temperature rise in the molten pool and spilling of the molten pool.

Figure 13 is a graph showing an example of the change over time in light source output (power) at each end 21a, 22a in the scanning path R100 shown in Figure 12. In Figure 13, the total value of the output of the laser device 111 that outputs the first laser light forming the beam B1 is shown by a solid line, and the total value of the output of the laser device 112 that outputs the second laser light forming the beam B2 is shown by a solid line.

As shown in FIG. 13, the light source output corresponding to beam B2 is constant between sections R101 and R109. The light source output corresponding to beam B1 is 0 in section R101, is constant in sections R104 and R108, and changes over time in sections R102, R103, R105, R107, and R109. In this case, sections R101, R104, and R108 are examples of constant power sections in which the irradiation position (spot S) moves while the power of the laser light L irradiated from the optical head 120 remains constant. Sections R102, R103, and R107 are examples of power increase sections in which the irradiation position (spot S) moves while the power of the laser light L irradiated from the optical head 120 increases over time, and are examples of power change sections. Moreover, sections R105 and R109 are examples of power decreasing sections in which the irradiation position (spot S) moves while the power of the laser light L irradiated from the optical head 120 decreases over time.

As is clear from Figure 13, the light source output in section R106, which is a turning point from scanning of laser light L in the Y direction in sections R101-R105 in Figure 12 to scanning of laser light L in the opposite direction to the Y direction in sections R107-R109, is set to be lower than the light source output in sections R104 and R108 before and after it, for example 80% or less. During movement in a non-linear scanning section such as a curved section like section R106 or a bent (knee-shaped) section (not shown), the spot S of the laser light L remains relatively close, so the irradiation energy density tends to be high. Therefore, as in the example of Figure 13, in section R106 as a non-linear scanning section, irradiation is performed with a lower power than in sections R104 and R108 as linear scanning sections, thereby preventing the irradiation energy density in section R106 from being higher than in the other sections R101 to R105 and R107 to R109, reducing the difference (variation) in irradiation energy density depending on the location of the ends 21a and 22a, and ultimately preventing spattering due to excessive temperature rise in the molten pool and spilling over of the molten pool.

In addition, by providing sections in which the light source output increases over time, such as sections R102, R103, and R107, it is possible to suppress the occurrence of spattering due to an excessive increase in the temperature of the molten pool and the spilling of the molten pool. Note that the increase over time may be a gradual increase or a stepwise increase.

Furthermore, by providing sections in which the light source output decreases over time, such as sections R105 and R109, it is possible to suppress the occurrence of voids and spatters that accompany increased movement of the molten pool, such as the disappearance of a keyhole due to a sudden drop in temperature of the molten pool. The decrease over time may be a gradual decrease or a step-by-step decrease.

In addition, in order to stabilize the state of the molten pool, the values of the power increase or decrease rate (rate of change) in sections R102, R103, R105, R107, and R109 can be set appropriately, and the increase or decrease rate (rate of change) may be changed over time.

13, the light source output in section R104, i.e., the maximum value of the light source output in sections R101 to R105 where the spot S moves in the Y direction, is the same as the light source output in section R108, i.e., the maximum value of the light source output in sections R107 to R109 where the spot S moves in the opposite direction to the Y direction. In this case, for example, advantages are obtained such as the fact that more energy can be input in a shorter period of time, thereby shortening the processing time, or making it easier to manage the operation of the laser devices 111 and 112.

Furthermore, although the second laser light has a relatively high absorptivity in materials, it has a short wavelength and relatively low convergence, making it difficult to efficiently apply energy to the material. On the other hand, although the first laser light has a relatively low absorptivity in materials, it has a long wavelength and relatively high convergence, making it easier to efficiently apply energy to the object W. Therefore, by irradiating the object W with the second laser light, the object W is preliminarily heated at a stage before irradiating the first laser light, and by irradiating the object W with the first laser light, energy for melting the object W is input, and the object W can be melted more efficiently while suppressing a sudden change in temperature of the object W.

From this viewpoint, as shown in FIG. 13, it is preferable to irradiate the first laser beam B1 from a stage before the irradiation, that is, in section R101, irradiate only the second laser beam B2 without irradiating the first laser beam B1. In this case, as shown in FIG. 12, the irradiation start position Ps0 of the second laser beam and the irradiation start position Ps1 of the first laser beam are different from each other. In the example of FIG. 12, the irradiation end position Pe of the first laser beam and the second laser beam in the Y direction is different from both the irradiation start position Ps0 of the second laser beam in the Y direction and the irradiation start position Ps1 of the first laser beam in the Y direction, but this is not limited to this, and the relative positional relationship between them can be appropriately set so that the state of the molten pool is gentle.

In addition, the second laser light may be irradiated at a fixed point for a certain period of time without scanning at the start of irradiation. This may allow the temperature of the object W to be raised to an appropriate temperature more quickly, and the object W to be processed more efficiently.

In addition, from the viewpoint of more efficiently melting the object W while suppressing abrupt temperature changes in the object W, it is preferable to keep the light source output of the second laser light approximately constant over time and to vary the light source output of the first laser light over time, as in the example of Figure 13.

[Yet another example of changing the light source output depending on the irradiation position of the scanning path]
Fig. 14 is a graph showing another example of the change over time of the light source output (power) at each end 21a, 22a in the scanning path R100 shown in Fig. 12. In Fig. 14 as well, the total value of the output of the laser device 111 that outputs the first laser light forming the beam B1 is shown by a solid line, and the total value of the output of the laser device 112 that outputs the second laser light forming the beam B2 is shown by a solid line.

As is clear from a comparison of Figures 13 and 14, in the example of Figure 14, the light source output in section R104 is set lower than the light source output in section R108. Experimental research by the inventors has revealed that in sections R102 and R103, if the light source output of the laser device 111 rises suddenly from a low state, the movement of the molten pool becomes more violent and spatter may be more likely to occur. Therefore, in the example of Figure 14, the light source output in section R104 is set lower than the light source output in section R108. In other words, the maximum value of the light source output in sections R101 to R105 is set lower than the maximum value of the light source output in sections R107 to R109. This makes it possible to make the state of the molten pool more gentle and suppress spatter. In the example of Figure 14, the value of the light source output in section R104 is set to the same value as the light source output in section R106, but this is not limited to this and can be changed and set as appropriate, for example, to a value greater than the light source output in section R106 and lower than the light source output in section R108.

In addition, in the examples shown in Figures 11 to 14, an increase in light source output may be appropriately replaced by a decrease in scanning speed, and a decrease in light source output may be appropriately replaced by an increase in scanning speed.

Yet another example of a scanning path
Fig. 15 is a plan view showing an example of a scanning path R100 of the laser light L at the end portions 21a, 22a. In the example of Fig. 15, the laser light L also scans the end portions 21a, 22a in a substantially U-shaped manner. However, in the example of Fig. 15, the laser light L scans at least partially in an area outside the areas A1, A2, i.e., an area farther from one end of the end portions 21a, 22a than the center C1, C2 in the X direction of the other end. Even when the laser light L scans along such a scanning path R100, it may be possible to form the required welded portion 23 and to suppress the generation of spatters due to an excessive temperature rise in the molten pool and the spilling of the molten pool.

As described above, according to this embodiment, the state of irradiation of the laser light can be changed according to the irradiation position of the laser light so that the difference in the irradiation energy density of the laser light depending on the location in the region where the laser light is irradiated at the ends 21a and 22a is reduced. This makes it possible to suppress an excessive increase in the temperature of the molten pool, and thus to obtain various effects such as suppressing the occurrence of spattering and suppressing spillage due to excessive growth of the molten pool.

Although the above describes embodiments and variations of the present invention, the above embodiments and variations are merely examples and are not intended to limit the scope of the invention. The above embodiments and variations can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, etc. (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

For example, in the above embodiment, the object was a rectangular wire, but the object is not limited to this and may be other conductive wires or other metal components. The object may also include three or more components. The multiple components included in the object do not have to be the same component. The object is not limited to multiple components lined up or butted together and may be multiple components stacked on top of each other.

For example, when irradiating the laser light, known wobbling, weaving, output modulation, etc. may be performed to adjust the surface area of the molten pool.

Furthermore, the scanned position, i.e., the irradiation area and the scanning path, are not limited to the examples described above and can be set in various ways.

Furthermore, the present invention can be implemented in the following forms.
(21)
In the laser welding method of the present invention, in at least a portion of the power change section, a rate of increase or decrease in the power of the irradiated laser light in response to movement of the irradiation position of the laser light may change over time.
(22)
In the laser welding method, in the step of irradiating the laser light, when the laser light is irradiated to a specified region of the first end portion or the second end portion, the laser light may be irradiated with a lower output than when the laser light is irradiated to another specified region.
(23)
In the laser welding method, the predetermined region may include a bent portion in a scanning path of the laser light, and the other predetermined region may be a region other than the predetermined region.
(24)
In the laser welding method, the predetermined region may be an edge region of the first end portion, and the other predetermined region may be a region of the first end portion other than the edge region.
(25)
In the laser welding method, the predetermined region may be an edge region of the first end portion, and the other predetermined region may include a center of the first end portion in the predetermined direction.
(26)
In the laser welding method, in the step of irradiating the laser light, a scanning speed of the laser light at the first end portion or the second end portion may be changed depending on an irradiation position of the laser light.
(27)
In the laser welding method, in the step of irradiating the laser light, the power of the irradiated laser light may be lowered as the scanning speed of the laser light at the first end portion or the second end portion is lower.
(28)
In the laser welding method, in the step of irradiating laser light, the power of the irradiated laser light may be increased or the scanning speed may be decreased as the radius of curvature of the scanning path of the laser light at the first end or the second end becomes larger.
(29)
In the laser welding method, in the step of irradiating the laser light, a scanning path of the irradiation position of the laser light at the first end or the second end may include a first section scanned linearly, a second section bent at a bending portion located at an end of the first section and scanned linearly in a direction different from the scanning direction of the first section, a first range within a predetermined distance from the bending portion in the first section, the second section, or the bending portion, and a second range in the first section or the second section that is outside the first range and is irradiated with laser light at a power higher than that of the first range.
(30)
In the laser welding method, in the step of irradiating the laser light, a scanning path of the irradiation position of the laser light at the first end or the second end includes a first section scanned linearly, and a second section bent at a bend located at an end of the first section and scanned linearly in a direction different from the scanning direction of the first section, the bent scanning section temporarily reduces the power of the laser light irradiated when passing through the bend from the first section to the second section, the bent scanning section having a plurality of bent scanning sections with different amounts of angle change from the scanning direction in the first section to the scanning direction in the second section, and the larger the amount of angle change in the plurality of bent scanning sections, the greater the amount of temporary power reduction.
(31)
In the laser welding method, in the step of irradiating the laser light, a scanning path of the irradiation position of the laser light at the first end or the second end includes a fourth section including an irradiation end close to an edge of the first end or the second end and an irradiation position farther from the edge than the irradiated end, and in the fourth section, the laser light may be irradiated with a lower power the closer the irradiation position is to the irradiated end.
(32)
In the laser welding method, in the step of irradiating the laser light, a scanning path of the irradiation position of the laser light at the first end or the second end may include a fourth section including an irradiation end close to an edge of the first end or the second end and an irradiation position farther from the edge than the irradiated end, a third range in the fourth section or the irradiated end within a predetermined distance from the edge or the irradiated end, and a fourth range in the fourth section that is outside the third range and is irradiated with laser light at a power higher than that of the third range.
(33)
In the laser welding method, in the step of irradiating the laser light, the second laser light may be irradiated at the scanning start position with a power higher than that at the irradiation position after the scanning start.
(34)
In the laser welding method, in the process of irradiating the laser light, the temperature of the molten pool may be detected, and the irradiation state of the laser light may be changed depending on the irradiation position of the laser light so that the irradiation energy density becomes lower as the temperature of the molten pool becomes higher.
(35)
In the laser welding method, in the step of irradiating the laser light, the movement of the molten pool may be detected, and the irradiation state of the laser light may be changed depending on the irradiation position of the laser light so that the irradiation energy density becomes lower as the movement of the molten pool becomes larger.
(36)
In the laser welding method, the metallic materials of the first member and the second member may each be any one of a copper-based metal and an aluminum-based metal.
(37)
In the laser welding method, the metallic material of the first member and the second member may be a conductive material.
(38)
The laser welding method of the present invention is a laser welding method for laser welding a first member made of a metallic material and a second member made of a metallic material, and includes the steps of irradiating at least one of the first member and the second member with a laser beam while scanning the first member and the second member, and solidifying a molten pool formed across the first member and the second member in the step of irradiating the laser beam. In the step of irradiating the laser beam, the irradiation state of the laser beam may be changed according to the irradiation position of the laser beam based on the temperature of the molten pool or the state of the radiation light output from the molten pool.

The present invention can be used in laser welding methods and laser welding apparatus.

10... Flat wire 20... Member 20a... End 21... Member (first member)
21a... End (first end)
21a1, 21a2... Edge 22... Member (second member)
22a... End (second end)
22a1, 22a2...edge 23...weld portion (molten pool)
30... Coating 100... Laser welding device 110, 111, 112... Laser device (light source)
120: Optical head 121: Collimator lens 122: Condenser lens 123: Filter 124: Mirror 125: DOE
126... Galvano scanner 126a, 126b... Mirror 130... Optical fiber 140... Driving mechanism 150... Sensor 200... Control device g... Gap A1... Area A2... Area B1, B2... Beam C1... Center C2... Center D1, D2... Lowering amount IA1, IA2... Irradiation area L... Laser light P1, P6... Irradiation positions P2 to P5... Irradiation position (bending portion)
Pe: Irradiation end position Pm1, Pm2, Pm4, Pm5: Intermediate positions Ps0, Ps1: Irradiation start positions R1, R2, R100: Scanning path R11 to R15: Section (first section, second section)
R21 to R24: Section (first section, second section)
R101: Section (first section, linear scanning section, constant power section)
R102: Section (first section, linear scanning section, power change section, power increase section)
R103: Section (first section, linear scanning section, power change section, power increase section)
R104: Section (first section, linear scanning section, constant power section)
R105...section (first section, linear scanning section, power change section, power decrease section, constant power section)
R106: Section (non-linear scanning section, constant power section)
R107: Section (second section, linear scanning section, power change section, power increase section)
R108: Section (second section, linear scanning section, constant power section)
R109: Section (second section, linear scanning section, power change section, power increase section)
S... Spot S1... Range (first range)
S2: Range (second range)
S3: Range (third range)
S4: Range (fourth range)
T...movement path W...object X...direction (second direction)
Y direction (third direction)
Z…direction (first direction)

Claims (7)

A laser welding method for laser welding a first end portion in a first direction of a first member made of a metallic material and a second end portion in the first direction of a second member made of a metallic material, the method comprising:
Arranging the first end portion and the second end portion so as to be adjacent to each other in a second direction intersecting the first direction;
irradiating at least one of the first end portion and the second end portion with a laser beam while scanning the laser beam in a predetermined direction intersecting the first direction;
solidifying a molten pool formed in the step of irradiating the laser beam and spanning the first end and the second end;
Equipped with
In the step of irradiating the laser light,
changing the power of the laser light to be irradiated in a region of the first end portion or the second end portion where the laser light is irradiated, depending on an irradiation position of the laser light;
a scanning path of the irradiation position of the laser light at the first end portion or the second end portion includes a linear scanning section in which the laser light is scanned linearly and a non-linear scanning section in which the laser light is scanned in a curved or bent manner,
the non-linear scanning section is irradiated with a laser beam having a power lower than a power of the laser beam irradiated to at least a portion of the linear scanning section . the linear scanning section includes a first section and a second section scanned in a direction opposite to that of the first section,
The laser welding method according to claim 1 , wherein a maximum value of a power of the laser beam irradiated in the first section is the same as a maximum value of a power of the laser beam irradiated in the second section. the linear scanning section includes a first section and a second section scanned in a direction opposite to that of the first section,
The laser welding method according to claim 1 , wherein a maximum value of a power of the laser beam irradiated in the first section and a maximum value of a power of the laser beam irradiated in the second section are different from each other. the second section is a section scanned after the first section,
The laser welding method according to claim 3 , wherein a maximum value of a power of the laser beam irradiated in the second section is greater than a maximum value of a power of the laser beam irradiated in the first section. the second section is a section scanned after the first section,
The non-linear scanning section is included between the first section and the second section,
The laser welding method according to claim 2 or 3 , wherein the first section and the second section are spaced apart from each other. A laser welding apparatus for laser welding a first end portion in a first direction of a first member made of a metal material and a second end portion in the first direction of a second member made of a metal material, the laser welding apparatus comprising:
A light source that outputs laser light;
an optical head that irradiates at least one of the first end and the second end with the laser light from the light source while scanning the laser light;
a control unit that variably controls at least one of an output of a laser beam from the light source and a scanning speed of the laser beam from the optical head;
a temperature sensor for detecting the temperature of the molten pool;
Equipped with
changing an irradiation state of the laser light in a region of the first end portion or the second end portion to be irradiated with the laser light according to an irradiation position of the laser light ;
The control unit of the laser welding device executes at least one of control to reduce the output of the laser light from the light source and control to increase the scanning speed as the temperature detected by the temperature sensor increases . a control unit that variably controls at least one of an output of a laser beam from the light source and a scanning speed of the laser beam from the optical head;
a motion sensor for detecting the motion of the surface of the molten pool;
Equipped with
7. The laser welding apparatus according to claim 6, wherein the control unit executes at least one of control to reduce the output of the laser light from the light source and control to increase the scanning speed as the movement of the surface detected by the movement sensor becomes larger.

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