JP2022011883A - Welding method, welding equipment and welding structure of metal conductor - Google Patents

Abstract

To obtain a welding method which dispenses with processing for differently removing a plating layer before welding even if a plurality of conductors including a metal conductor in which, for example, the plating layer is formed, are welded, welding equipment and a welding structure of the metal conductor.SOLUTION: In a welding method for performing welding by irradiating laser beams on surfaces of processing objects being a plurality of metal conductors including at least one metal conductor in which, for example, a plating layer is formed, the laser beams include a first laser beam whose wave length is equal to or longer than 800[nm] and equal to or shorter than 1200[nm], and a second laser beam whose wave length is equal to or shorter than 500[nm], and the plating layer is removed by the irradiation of the second laser beam. In the welding method, the wave length of the second laser beam may be equal to or longer than 400[nm] and equal to or shorter than 500[nm]. Also, in the welding method, the plating layer may be a tin-plated layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a welding method, a welding device, and a welded structure of a metal conductor.

Conventionally, a welding method for welding metal conductors such as bus bars and terminals by irradiating with a laser beam is known (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-168340

In this type of welding, a plating layer may be formed on one of the metal conductors. If the material forming the plating layer during welding melts and mixes into the welded portion, the joint strength may be weakened.

As a countermeasure, a process of removing the plating layer may be performed by separately irradiating a pulse laser before welding. However, in that case, there is a problem that the processing time becomes long due to the process of removing the plating layer, and the labor and cost of processing increase.

Therefore, one of the problems of the present invention is that, for example, even when welding a plurality of conductors including a metal conductor on which a plating layer is formed, it is necessary to separately remove the plating layer before the welding. No welding method, welding equipment, and obtaining a welded structure of metal conductors.

The welding method of the present invention is, for example, a welding method in which a surface of a processing target, which is a plurality of metal conductors including at least one metal conductor on which a plating layer is formed, is irradiated with a laser beam and welded. Includes a first laser beam having a wavelength of 800 [nm] or more and 1200 [nm] or less, and a second laser beam having a wavelength of 500 [nm] or less, and the plating layer is irradiated with the second laser beam. To remove.

In the welding method, for example, the wavelength of the second laser beam is 400 [nm] or more and 500 [nm] or less.

In the welding method, for example, the plating layer is a tin plating layer.

In the welding method, for example, at least one of the plurality of metal conductors is made of a copper-based material.

In the welding method, for example, the laser beam is swept in a sweep direction on the surface of the laser beam, and at least a part of a second spot formed on the surface by the second laser beam on the surface. Is located in front of the first spot formed on the surface by the first laser beam in the sweep direction.

In the welding method, for example, the first spot and the second spot overlap at least partially on the surface.

In the welding method, for example, on the surface, the second outer edge of the second spot surrounds the first outer edge of the first spot.

In the welding method, for example, the power density of the second laser beam on the surface is 0.16 [MW / cm ² ] or more and 1.5 [MW / cm ² ] or less.

In the welding method, for example, the thickness of the metal conductor having the surface among the plurality of metal conductors is 0.5 [mm] or more and less than 1 [mm], and the surface is subjected to the first laser beam. When is a plane perpendicular to the laser beam, the spot diameter of the first spot formed on the plane is 20 [μm] or more and 80 [μm] or less, and the power of the first laser beam is When the surface is a plane perpendicular to the laser beam by the second laser beam, the spot diameter of the first spot formed on the plane is 0.3 [kW] or more and 6 [kW] or less. , 50 [μm] or more and 400 [μm] or less, and the power of the second laser beam is 0.05 [kW] or more and 1 [kW] or less.

In the welding method, for example, the energy density of the first laser beam per unit volume in the irradiation direction of the laser beam in the welded portion of the plurality of metal conductors is 200 [J / mm ³ ] or more, and the welding. The energy density of the second laser beam per unit volume in the irradiation direction of the laser beam in the unit is 5 [J / mm ³ ] or more and 49 [J / mm ³ ] or less.

Further, the welding apparatus of the present invention includes, for example, a laser oscillator and an optical head that irradiates a plurality of metal conductors including at least one metal conductor on which a plating layer is formed with a laser beam from the laser oscillator. A welding device for welding a plurality of metal conductors, the laser light is a first laser light having a wavelength of 800 [nm] or more and 1200 [nm] or less, and a second laser light having a wavelength of 500 [nm] or less. The plating layer is removed by irradiation with the second laser beam, including a laser beam.

The welding device includes, for example, a beam shaper that divides the laser beam into a plurality of beams.

The welding device includes, for example, a galvano scanner that changes the irradiation direction of the laser beam so as to sweep the laser beam in the sweep direction on the surface.

The welding device includes, for example, a detection mechanism for detecting a deviation of a spot formed on the surface of the surface by the laser beam with respect to a predetermined position, and a correction mechanism for correcting the deviation.

In the welding device, for example, the correction mechanism changes the relative position of the plurality of metal conductors and the optical head.

In the welding apparatus, for example, the correction mechanism includes a galvano scanner that changes the irradiation direction of the laser beam so as to sweep the laser beam in the sweep direction on the surface.

Further, the welded structure of the metal conductor of the present invention includes, for example, a plurality of metal conductors including at least one first metal conductor on which a plating layer is formed, and a welded portion obtained by welding the plurality of metal conductors. , A welded structure of a metal conductor, wherein the welded portion includes a welded metal extending from the surface of the welded structure of the metal conductor in a direction intersecting the surface, and a heat-affected portion located around the weld metal. The weld metal has, ing.

In the welded structure of the metal conductor, for example, the weld extends along the surface.

In the welded structure of the metal conductor, for example, the weld penetrates the first metal conductor and extends from the first metal conductor to another metal conductor.

In the welded structure of the metal conductor, for example, the weld extends along a boundary between the first metal conductor and another metal conductor adjacent to the first metal conductor.

In the welded structure of the metal conductor, for example, the weld extends across the boundary between the first metal conductor and another metal conductor adjacent to the first metal conductor.

According to the present invention, for example, even when welding a plurality of conductors including a metal conductor on which a plating layer is formed, a welding method and welding that do not require a separate treatment for removing the plating layer before the welding. Welded structures of equipment and metal conductors can be obtained.

FIG. 1 is an exemplary schematic configuration diagram of the laser welding apparatus of the first embodiment. FIG. 2 is an exemplary schematic diagram showing a beam (spot) of laser light formed on the surface of a processing target by the laser welding apparatus of the first embodiment. FIG. 3 is a graph showing the light absorption rate of each metal material with respect to the wavelength of the irradiated laser light. FIG. 4 is an exemplary and schematic cross-sectional view of the welded portion of the embodiment. FIG. 5 is an exemplary and schematic cross-sectional view showing a portion of the welded portion of the embodiment. FIG. 6 is a graph showing the experimental results of welding in the combination of the power density of the first laser beam and the power density of the second laser beam by the laser welding apparatus of the embodiment. FIG. 7 is an explanatory diagram showing the concept of the principle of the diffractive optical element included in the laser welding apparatus of the first embodiment. FIG. 8 is a schematic plan view showing an example of the welded structure of the metal conductor of the embodiment. FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. FIG. 10 is a schematic plan view showing an example of the welded structure of the metal conductor of the embodiment. 11 is a sectional view taken along the line XI-XI of FIG. FIG. 12 is a schematic plan view showing an example of the welded structure of the metal conductor of the embodiment. FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. FIG. 14 is a schematic plan view showing an example of the welded structure of the metal conductor of the embodiment. FIG. 15 is a schematic cross-sectional view at the same position as FIG. 9, which shows an example of the welded structure of the metal conductor of the embodiment. FIG. 16 is an exemplary schematic configuration diagram of the laser welding apparatus of the second embodiment. FIG. 17 is an exemplary schematic configuration diagram of the laser welding apparatus of the third embodiment.

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

The embodiments shown below have similar configurations. Therefore, according to the configuration of each embodiment, the same operation and effect based on the similar configuration can be obtained. Further, in the following, the same reference numerals are given to those similar configurations, and duplicate explanations may be omitted.

Further, in each figure, the X direction is represented by an arrow X, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X, Y, and Z directions intersect and are orthogonal to each other. The Z direction is the normal direction of the surface Wa (processed surface, welded surface) of the processing target W. Further, in each figure, for convenience, an example in which the sweep direction SD on the surface Wa of the laser beam L is along the X direction is shown, but the sweep direction SD should be along the surface Wa and intersect the Z direction. It is good, not only along the X direction.

Further, in the present specification, the ordinal number is given for convenience in order to distinguish parts, members, parts, laser beams, directions, etc., and does not indicate a priority or an order.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of the laser welding apparatus 100 of the first embodiment. As shown in FIG. 1, the laser welding device 100 includes a laser device 111, a laser device 112, an optical head 120, an optical fiber 130, and a controller 141. The laser welding device 100 is an example of a welding device.

Each of the laser devices 111 and 112 has a laser oscillator, and is configured to be capable of outputting, for example, a laser beam having a power of several kW. The laser devices 111 and 112 irradiate laser light having a wavelength of 380 [nm] or more and 1200 [nm] or less. The laser devices 111 and 112 have a laser light source such as a fiber laser, a semiconductor laser (element), a YAG laser, and a disk laser inside. The laser devices 111 and 112 may be configured to be capable of outputting multimode laser light having a power of several kW as the total of the outputs of the plurality of light sources.

The laser apparatus 111 outputs the first laser beam having a wavelength of 800 [nm] or more and 1200 [nm] or less. The laser device 111 is an example of the first laser device. As an example, the laser apparatus 111 has a fiber laser or a semiconductor laser (element) as a laser light source. The laser oscillator included in the laser device 111 is an example of the first laser oscillator.

On the other hand, the laser device 112 outputs a second laser beam having a wavelength of 500 [nm] or less. The laser device 112 is an example of a second laser device. As an example, the laser device 112 has a semiconductor laser (element) as a laser light source. The laser device 112 preferably outputs a second laser beam having a wavelength of 400 [nm] or more and 500 [nm] or less. The laser oscillator included in the laser device 112 is an example of a second laser oscillator.

The optical fiber 130 guides the laser light output from the laser devices 111 and 112 to the optical head 120, respectively.

The optical head 120 is an optical device for irradiating the laser beam input from the laser devices 111 and 112 toward the processing target W. The optical head 120 includes a collimating lens 121, a condenser lens 122, a mirror 123, and a filter 124. The collimating lens 121, the condenser lens 122, the mirror 123, and the filter 124 may also be referred to as optical components.

The optical head 120 is configured so that the relative position with the processing target W can be changed in order to sweep the laser light L while irradiating the surface Wa of the processing target W with the laser light L. The relative movement between the optical head 120 and the processing target W can be realized by the movement of the optical head 120, the movement of the processing target W, or the movement of both the optical head 120 and the processing target W.

The optical head 120 may be configured to be able to sweep the laser beam L on the surface Wa by having a galvano scanner or the like (not shown).

The collimating lenses 121 (121-1, 121-2) collimate the laser beam input via the optical fiber 130, respectively. The collimated laser beam becomes parallel light.

The mirror 123 reflects the first laser beam that has become parallel light by the collimating lens 121-1. The first laser beam reflected by the mirror 123 travels in the opposite direction to the Z direction and heads toward the filter 124. The mirror 123 is not required in the configuration in which the first laser beam is input to the optical head 120 so as to travel in the direction opposite to the Z direction.

The filter 124 is a high-pass filter that transmits the first laser beam and reflects the second laser beam without transmitting it. The first laser beam passes through the filter 124, travels in the opposite direction in the Z direction, and heads toward the condenser lens 122. On the other hand, the filter 124 reflects the second laser beam that has become parallel light by the collimated lens 121-2. The second laser beam reflected by the filter 124 travels in the opposite direction to the Z direction and heads toward the condenser lens 122.

The condenser lens 122 concentrates the first laser beam and the second laser beam as parallel light, and irradiates the processing target W as the laser beam L (output light).

Further, the laser welding device 100 includes a controller 141 and a controlled mechanism whose operation is controlled by the controller 141. In the present embodiment, the laser welding device 100 includes, for example, a drive mechanism 150 as a controlled mechanism.

The drive mechanism 150 changes the relative position of the optical head 120 with respect to the processing target W. The drive mechanism 150 includes, for example, a rotation mechanism such as a motor, a deceleration mechanism for decelerating the rotation output of the rotation mechanism, a motion conversion mechanism for converting the rotation decelerated by the deceleration mechanism into linear motion, and the like. The controller 141 can control the drive mechanism 150 so that the relative positions of the optical head 120 with respect to the processing target W in the X direction, the Y direction, and the Z direction change. The controller 141 may control the operation of the laser devices 111 and 112 and the camera 170.

Further, the laser welding apparatus 100 includes a camera 170, a filter 127 and a mirror 128 as optical components for guiding light to the camera 170. The filter 127 is provided between the mirror 123 and the filter 124. The filter 127 transmits the first laser light from the mirror 123 toward the filter 124 and reflects the light from the surface Wa (for example, visible light) toward the mirror 128. The light reflected by the mirror 128 is input to the camera 170. With such a configuration, the camera 170 can capture an image on the surface Wa. The image captured by the camera 170 may include, for example, an image of the surface Wa and an image of a beam (spot) by the laser beam L. Therefore, the image captured by the camera 170 can be said to be the detection result of the deviation of the spot formed on the surface Wa with respect to a predetermined position, and the camera 170 can be said to be an example of the sensor for detecting the deviation. .. When the position of the spot at the angle of view of the photographed image is fixed, the photographed image may include the irradiation target of the laser beam L, and the image of the spot needs to be included. There is no. The camera 170 and the controller 141 are examples of the detection mechanism.

Further, the controller 141 can control the drive mechanism 150 so as to detect a deviation of the spot with respect to a predetermined position from the image captured by the camera 170 and correct the deviation. Further, the controller 141 may execute feedback control so that the deviation is within a predetermined threshold value. The controller 141 and the drive mechanism 150 are examples of the correction mechanism. With such a configuration, the accuracy of the irradiation position of the laser beam can be improved.

The processing target W is a welded structure 10 having a plurality of metal conductors 11 and 12. The metal conductors 11 and 12 are joined by a welded portion 14.

When the welding structure 10 is welded by the laser welding device 100, it is temporarily fixed integrally by a fixture (not shown), and is set, for example, in a posture in which the normal direction of the surface Wa is substantially parallel to the Z direction. .. In the configuration shown in FIG. 1, as an example, the surface Wa intersects the Z direction at the end portion in the Z direction and extends orthogonally to the welded portion of the welded structure 10. The surface Wa can also be referred to as an irradiated surface of the laser beam L.

The optical head 120 irradiates the laser beam L toward the surface Wa in the direction opposite to the Z direction. The surface Wa is an irradiation surface of the laser beam L, and may also be referred to as a facing surface facing the optical head 120. The direction opposite to the Z direction can be referred to as the irradiation direction of the laser beam L.

By such irradiation of the laser beam L, the welded portion 14 extends from the surface Wa in the direction opposite to the Z direction. The direction opposite to the Z direction can also be referred to as the depth direction of the welded portion 14. The depth direction of the welded portion 14 is also the irradiation direction of the laser beam L.

Further, in a state where the laser beam L is irradiated, the optical head 120 moves relative to the processing target W in the sweep direction SD by the operation of the drive mechanism 150, so that the laser beam L is transferred on the surface Wa. It is swept in the sweep direction SD. As a result, the welded portion 14 has a cross-sectional shape substantially similar to that in FIG. 1, and extends along the surface Wa in the sweep direction SD (X direction in FIG. 1). The sweep direction SD may also be referred to as a longitudinal direction or an extension direction of the welded portion 14. Further, the direction intersecting the Z direction and the sweep direction SD (Y direction in FIG. 1) can also be referred to as a width direction of the welded portion 14.

FIG. 2 is a schematic diagram showing a beam (spot) of a laser beam L irradiated on a flat surface Wa. Each of the beam B1 and the beam B2 has, for example, a Gaussian-shaped power distribution in the radial direction of the cross section orthogonal to the optical axis direction of the beam. However, the power distribution of the beam B1 and the beam B2 is not limited to the Gaussian shape. Further, in each figure in which each beam B1 and B2 is represented by a circle as shown in FIG. 2, the diameter of the circle representing the beams B1 and B2 is the beam diameter of each beam B1 and B2. The beam diameter of each beam B1 and B2 includes the peak of the beam and is defined as the diameter of a region having an intensity of 1 / e2 or ^more of the peak intensity. Although not shown, in the case of a non-circular beam, the length of a region having an intensity of 1 / e2 or ^more of the peak intensity in the direction perpendicular to the sweep direction SD (Y direction in the figure) can be defined as the beam diameter. .. Further, the beam diameter on the surface Wa is referred to as a spot diameter.

As shown in FIG. 2, in the present embodiment, as an example, in the beam of the laser beam L, the beam B1 of the first laser beam and the beam B2 of the second laser beam overlap on the surface Wa, and the beam B2 is formed. It is larger (wider) than the beam B1 and is formed so that the outer edge B2a of the beam B2 surrounds the outer edge B1a of the beam B1. In this case, the spot diameter D2 of the beam B2 is larger than the spot diameter D1 of the beam B1. On the surface Wa, the beam B1 is an example of the first spot, and the beam B2 is an example of the second spot.

Further, in the present embodiment, as shown in FIG. 2, since the beam (spot) of the laser beam L has a point-symmetrical shape with respect to the center point C on the surface Wa, for any sweep direction SD. , The shape of the spot will be the same. Therefore, when a moving mechanism for relatively moving the optical head 120 and the processing target W for sweeping the surface Wa of the laser beam L is provided, the moving mechanism should have at least a relatively translatable mechanism. However, the relatively rotatable mechanism may be omitted.

[Wavelength and light absorption rate]
Here, the light absorption rate of the metal material will be described. FIG. 3 is a graph showing the light absorption rate of each metal material with respect to the wavelength of the laser light L to be irradiated. The horizontal axis of the graph of FIG. 3 is the wavelength, and the vertical axis is the absorption rate. FIG. 3 shows the relationship between wavelength and absorption for aluminum (Al), copper (Cu), gold (Au), nickel (Ni), silver (Ag), tantalum (Ta), and titanium (Ti). It is shown.

Although the characteristics differ depending on the material, for each metal shown in FIG. 3, a blue or green laser beam (second laser) is used rather than using a general infrared (IR) laser beam (first laser beam). It can be understood that the energy absorption rate is higher when light) is used. This feature is remarkable in copper (Cu), gold (Au), and the like.

When the laser beam is applied to the processing target W having a relatively low absorption rate with respect to the wavelength used, most of the light energy is reflected and does not affect the processing target W as heat. Therefore, it is necessary to apply a relatively high power in order to obtain a melting region having a sufficient depth. In that case, energy is suddenly applied to the central part of the beam, so that sublimation occurs and a keyhole is formed.

On the other hand, when the laser beam is applied to the processing target W having a relatively high absorption rate with respect to the wavelength used, most of the input energy is absorbed by the processing target W and converted into thermal energy. That is, since it is not necessary to apply excessive power, heat conduction type melting is performed without forming keyholes.

In the present embodiment, the wavelength of the first laser beam, the wavelength of the second laser beam, and the wavelength of the processing target W are such that the absorption rate of the processing target W with respect to the second laser light is higher than the absorption rate with respect to the first laser light. The material is selected. In this case, when the sweep direction is the sweep direction SD shown in FIG. 2, the portion to be welded (hereinafter referred to as the welded portion) of the work target W due to the sweep of the spot of the laser beam L is first, first. The second laser beam is irradiated by the region B2f of the beam B2 of the second laser beam located in front of the SD in FIG. After that, the welded portion is irradiated with the beam B1 of the first laser beam, and then the second laser beam is irradiated again by the region B2b of the beam B2 of the second laser beam located behind the sweep direction SD. To.

Therefore, in the welded portion, a heat conduction type melting region is first generated by irradiation with a second laser beam having a high absorption rate in the region B2f. After that, a deeper keyhole-type melting region is generated in the welded portion by irradiation with the first laser beam. In this case, since the heat conduction type melting region is formed in advance in the welded portion, the required depth is obtained by the first laser beam having a lower power than in the case where the heat conduction type melting region is not formed. A molten region can be formed. After that, the welded portion is changed in a molten state by irradiation with a second laser beam having a high absorption rate in the region B2b.

Further, experimental studies by the inventors have confirmed that welding defects such as spatters and blowholes can be reduced in welding by irradiation with a laser beam L as shown in FIG. This is because the work target W is preheated by the region B2f of the beam B2 before the beam B1 arrives, so that the molten pool of the work target W formed by the beam B2 and the beam B1 becomes more stable. It can be estimated that there is.

[Welding method]
In welding using the laser welding apparatus 100, first, the welding structure 10 in which the metal conductor 11 and the metal conductor 12 are integrally temporarily fixed by a holder (not shown) irradiates the surface Wa with the laser beam L. It is set to be done. Then, in a state where the surface Wa is irradiated with the laser beam L including the beam B1 and the beam B2, the laser beam L and the welded structure 10 are relatively moved. As a result, the laser beam L moves (sweeps) in the sweep direction SD on the surface Wa while being irradiated on the surface Wa. The portion irradiated with the laser beam L melts, and then solidifies as the temperature decreases, so that the metal conductor 11 and the metal conductor 12 are joined via the welded portion 14, and the welded structure 10 is integrated. Will be done.

[Cross section of weld]
FIG. 4 is a cross-sectional view of a welded portion 14 formed on the processing target W. FIG. 4 is a cross-sectional view perpendicular to the sweep direction SD (X direction in FIG. 4) and along the thickness direction (Z direction). The welded portion 14 extends in the sweep direction SD, that is, in the direction perpendicular to the paper surface of FIG. Note that FIG. 4 shows a cross section of the welded portion 14 formed on the processing target W, which is a single copper plate having a thickness of 2 [mm]. It is estimated that the form of the welded portion 14 formed over the plurality of metal conductors 11 and 12 is substantially the same as the form of the welded portion 14 formed on the processing target W which is one metal material shown in FIG. can.

As shown in FIG. 4, the welded portion 14 has a welded metal 14a extending in the opposite direction in the Z direction from the surface Wa, and a heat-affected zone 14b located around the welded metal 14a. .. The weld metal 14a is a portion that is melted by irradiation with the laser beam L and then solidified. The weld metal 14a may also be referred to as a melt-solidified portion. Further, the heat-affected zone 14b is a portion where the base material of the processing target W is thermally affected and is not melted.

The width of the weld metal 14a along the Y direction becomes narrower as the distance from the surface Wa increases. That is, the cross section of the weld metal 14a has a tapered shape that narrows in the direction opposite to the Z direction.

Further, according to a detailed analysis of the cross section by the inventors, the weld metal 14a includes a first portion 14a1 away from the surface Wa and a second portion 14a2 between the first portion 14a1 and the surface Wa. There was found.

The first portion 14a1 is a region obtained by keyhole-type melting by irradiation with the first laser beam, and the second portion 14a2 is a region located behind the sweep direction SD in the beam B2 of the second laser beam. It is a part obtained by melting by irradiation of B2b. According to the analysis by the EBSD method (electron back scattered diffraction pattern), the size of the crystal grains is different between the first site 14a1 and the second site 14a2, and specifically, the X direction (sweep direction). It was found that the average cross-sectional area of the crystal grains at the second site 14a2 was larger than the average cross-sectional area of the crystal grains at the first site 14a1 in the cross section orthogonal to SD).

The inventors have found that when the processing target W is irradiated with only the beam B1 of the first laser beam, that is, when the region B2b located behind the sweep direction SD in the beam B2 is not irradiated, the second It was confirmed that the site 14a2 was not formed and the first site 14a1 extended deeply from the surface Wa in the opposite direction to the Z direction. That is, in the present embodiment, the second portion 14a2 is formed near the surface Wa by the irradiation of the region B2b located behind the sweep direction SD in the beam B2, so that the first portion 14a1 is the said. It can be presumed that the second portion 14a2 is formed on the opposite side of the surface Wa, in other words, at a position separated from the surface Wa in the opposite direction in the Z direction.

FIG. 5 is a cross-sectional view showing a part of the welded portion 14. FIG. 5 shows the boundaries of the crystal grains obtained by the EBSD method. Further, in FIG. 5, as an example, the crystal grain A having a crystal grain size of 13 [μm] or less is painted black. Note that 13 [μm] is not a threshold value of physical characteristics, but a threshold value set for analysis of the experimental results. Further, from FIG. 5, it is clear that the crystal grains A are relatively abundant in the first site 14a1 and relatively few in the second site 14a2. That is, the average cross-sectional area of the crystal grains in the second site 14a2 is larger than the average cross-sectional area of the crystal grains in the first site 14a1. According to an experimental analysis, the inventors have found that the average cross-sectional area of the crystal grains in the second site 14a2 is 1.8 times or more the average cross-sectional area of the crystal grains in the first site 14a1. It was confirmed.

As shown in the region I in FIG. 5, such relatively small crystal grains A are densely packed in a position separated from the surface Wa in the Z direction and elongated in the Z direction. There is. Further, from the analysis at a plurality of locations where the positions in the X direction (sweep direction SD) are different, it is confirmed that the region where the crystal grains A are densely extends extends to the sweep direction SD. Since the welding is performed while sweeping, it can be estimated that crystals are formed in the same shape in the sweep direction SD.

When it is difficult to distinguish between the first portion 14a1 and the second portion 14a2 from the appearance or hardness distribution in the cross section, geometry is performed from the position and width wb of the weld metal 14a on the surface Wa as shown in FIGS. The geographically determined first region Z1 and second region Z2 may be designated as the first region 14a1 and the second region 14a2, respectively. As an example, the first region Z1 and the second region Z2 are rectangular regions extending in the Z direction with a width wm (equal width in the Y direction) in a cross section orthogonal to the sweep direction SD, and the second region Z2. Is a region from the surface Wa to the depth d in the Z direction, and the first region Z1 is a region deeper than the depth d, in other words, a region opposite to the surface Wa with respect to the position of the depth d. can do. The width wm is, for example, 1/3 of the width wb (average value of the bead width) on the surface Wa of the weld metal 14a, and the depth d (height, thickness) of the second region Z2 is, for example, the width wb. Can be 1/2 of. Further, the depth of the first region Z1 can be, for example, three times the depth d of the second region Z2. The inventors have conducted experimental analysis on a plurality of samples, and in such a setting of the first region Z1 and the second region Z2, the average value of the cross-sectional areas of the crystal grains in the second region Z2 is in the first region Z1. It was confirmed that it was larger than the average value of the cross-sectional area of the crystal grains and was 1.8 times or more. Such discrimination can also be evidence that the first portion 14a1 and the second portion 14a2 are formed in the weld metal 14a by welding.

[Laser light power density]
FIG. 6 is a graph showing the experimental results of welding in the combination of the power density Pd1 of the first laser beam and the power density Pd2 of the second laser beam on the surface Wa of the processing target W. In FIG. 6, "○" indicates that the number of blow holes is very small (excellent), "△" indicates that the number of blow holes is small, and "×" indicates that the number of blow holes is large (impossible). Is shown. Here, as an example, "excellent" indicates the case where the number of blow holes per unit length (for example, 1 [cm]) of the linear welded portion is one or less, and "good" indicates welding. The case where the number of blow holes per unit length of the portion is 2 or more and less than 5 is indicated, and "impossible" indicates the case where the number of blow holes per unit length of the welded portion is 5 or more. .. Further, in this experiment, the wavelength of the first laser beam is 1070 [nm] and the output is 1.5 [kW], the wavelength of the second laser beam is 450 [nm], and the output is 150 [W]. ]Met.

As shown in FIG. 6, when the power density Pd2 of the second laser beam is 0.16 [MW / cm ² ] or more and 1.5 [MW / cm ² ] or less, the number of blow holes can be suppressed. There was found. This is because when the power density Pd2 of the second laser beam is less than 0.16 [MW / cm ² ] (lower limit value), the amount of light energy absorbed by the copper plate surface is insufficient, so that the preheating effect is sufficient. This is because it cannot be obtained, and when the power density Pd2 is larger than 1.5 [MW / cm ² ] (upper limit value), it is considered that the keyhole type melting occurs even in the second laser. ..

[DOE]
Further, as shown in FIG. 1, the optical head 120 has a DOE 125 between the collimating lens 121-1 and the mirror 123.

The DOE125 forms the shape of the beam B1 of the first laser beam (hereinafter referred to as the beam shape). As conceptually illustrated in FIG. 7, the DOE 125 has, for example, a configuration in which a plurality of diffraction gratings 125a having different periods are superposed. The DOE 125 can form a beam shape by bending or superimposing parallel light in a direction affected by each diffraction grating 125a. DOE125 may also be referred to as a beam shaper.

The optical head 120 is provided after the collimating lens 121-2 and has a beam shaper for adjusting the beam shape of the second laser beam, and is provided after the filter 124 and has the beam shapes of the first laser beam and the second laser beam. It may have a beam shaper or the like to be adjusted. By appropriately adjusting the beam shape of the laser beam L by the beam shaper, it is possible to further suppress the occurrence of welding defects in welding. Further, the DOE 125 can divide the beam of the first laser beam into a plurality of beams.

[Thickness of metal conductor, spot diameter of each beam, power of each beam]
Further, the inventors have conducted an experimental analysis to determine the thickness of the metal conductor (metal conductor 11 in the example of FIG. 1) having the surface Wa irradiated with the laser beam L, on the surface Wa of each beam B1 and B2. With respect to the beam diameter (spot diameter) and the power of each of the beams B1 and B2, the conditions for obtaining a suitable welded state in the welded structure 10 have been found. Here, the preferable welding state means that the state of the blow hole is the above-mentioned "excellent" or "good".

According to the experimental analysis by the inventors, when the thickness T (see FIG. 1) of the metal conductor 11 in the Z direction is 0.2 [mm] or more and 1 [mm] or less,
The spot diameter (first spot diameter) due to the beam B1 is 20 [μm] or more and 80 [μm] or less, and
The power of the beam B1 (output of the laser device 111) is 0.3 [kW] or more and 6 [kW] or less, and
The spot diameter (first spot diameter) of the beam B2 is 50 [μm] or more and 400 [μm] or less, and
It has been found that a suitable welded state can be obtained when the power of the beam B1 (output of the laser device 112) is 0.05 [kW] or more and 1 [kW] or less.

[Energy density]
Further, in the experimental analysis, the inventors introduced a new index of the energy density of laser light irradiation per unit volume of the welded structure 10, and the conditions under which a suitable welded state can be obtained for the energy density. I found it. The energy density can be expressed by the following equation (1).
_En = P _n / (V × D _n × Ta) ・ ・ ・ (1)
Here, En is the energy density [J / mm ³ ], P _n is the power [W] of the laser beam generated by the laser device, V is the sweep speed [mm / s], and D _{n is} the spot on the surface Wa. The diameter [mm] and Ta are the thickness [mm] of the welded structure 10 in the Z direction (see FIG. 1). Here, each parameter is distinguished by the subscript n, where n = 1 indicates the parameter of the first laser beam and n = 2 indicates the parameter of the second laser beam.

According to the experimental analysis of the inventors, when the thickness Ta of the welded structure 10 in the Z direction is 0.2 [mm] or more and 1 [mm] or less, the energy density E1 of the beam _B1 is determined. A suitable welded state is obtained when the energy density E 2 of the beam B2 is 200 [J / mm ³ ] or more and the energy density E ₂ of the beam B2 is 5 [J / mm ³ ] or more and 49 [J / mm ³ ] or less. It turned out to be.

[Example of welded structure]
8 to 15 show an example of the welding structure 10 (10-1 to 10-5) formed by the laser welding apparatus 100. In each of the examples of FIGS. 8 to 15, the metal conductor 11 is a terminal connected to the end of the harness, and the metal conductor 12 is electrically and electrically connected via the metal conductor 11 and the welded portion 14 which are the terminals. It is a bus bar that is mechanically connected. In the examples of FIGS. 8 to 15, the irradiation direction of the laser beam L is the depth direction (described later) of each welded portion 14, and is not limited to the direction opposite to the Z direction.

Further, in each of the examples of FIGS. 8 to 15, the metal conductor 11 has a flat and annular ring. Further, the metal conductor 12 has a flat plate shape and has a protrusion 12b protruding in the Z direction from the end surface 12a in the thickness direction (Z direction). The protrusion 12b has a columnar shape extending in the Z direction, and is inserted into the cylindrical through hole 11a (inner peripheral surface) extending in the Z direction of the metal conductor 11. Further, the end surface of the ring portion of the metal conductor 11 in the Z direction and the end surface of the protrusion 12b are substantially flush with each other and extend so as to intersect the Z direction. The ring portion and the protrusion 12b of the metal conductor 11 suppress the misalignment and separation between the metal conductor 11 and the metal conductor 12. In such a configuration, between the metal conductor 11 and the metal conductor 12, a cylindrical boundary BL1 between the through hole 11a and the protrusion 12b and a flat and circular boundary between the metal conductor 11 and the end surface 12a are formed. An annular boundary BL2 is provided. The examples of FIGS. 8 to 15 are only examples, and the example of the welded structure 10 is not limited to these configurations.

At least one of the metal conductor 11 and the metal conductor 12 is made of a copper-based material, for example pure copper. Further, a plating layer such as tin plating is formed on the surface of at least one of the metal conductor 11 and the metal conductor 12. In other words, at least one of the metal conductor 11 and the metal conductor 12 (first metal conductor) is plated. When the material forming the plating layer is mixed into the welded portion 14 when the plurality of metal conductors 11 and 12 are welded, the joint strength of the welded portion 14 may be weakened. Therefore, in the laser welding apparatus 100 of the present embodiment, the laser beam L is such that the plating layer evaporates before the welded portion 14 is formed by the irradiation of the laser beam L including the first laser beam and the second laser beam. The portion to be welded is heated by irradiating the second laser beam contained in the above. As an example, as shown in FIG. 2, when the region B2f of the beam B2 of the second laser beam is in front of the sweep direction SD with respect to the beam B1 of the first laser beam, the beams B1 and the beam B2 are combined. By sweeping the surface Wa in the sweep direction SD, the region B2f of the beam B2 can be irradiated and heated before the region to be welded is irradiated with the beam B1. In this case, for example, the power and power density of the laser devices 111 and 112, the spot diameters of the beams B1 and B2, the arrangement of the beams B1 and B2, the sweep speed of the laser beam L relative to the processing target W, and the like are appropriately set. By doing so, it is possible to realize a temperature rise exceeding the melting point of the plating layer on the surface Wa, evaporation of the plating layer based on the temperature rise, and high-quality welding. The melting point of the plating layer is lower than the melting points of both of the plurality of metal conductors 11 and 12. As an example, in the case of tin plating, the melting point of tin, which is the main component of the plating layer, is 232 ° C. The inventors can realize a temperature rise exceeding the melting point (232 ° C.) by irradiating the laser beam L including the beam B1 and the beam B2 and sweeping the laser beam L to the sweep direction SD, and at the same time, high quality. It was confirmed that a good welding can be realized. Further, in the present embodiment, the beam B1 and the beam B2 are simultaneously irradiated as the laser beam L, and the beam B1 and the beam B2 are, for example, in contact with each other or at least partially overlapped with each other at a predetermined distance. It is arranged so that it does not exceed and separate. As a result, in addition to the energy given to the processing target W by the beam B2, the energy given to the processing target W by the beam B1 also contributes to the temperature rise of the surface Wa before the welded portion 14 is formed and the evaporation of the plating layer. do. With such a setting, the plating layer can be removed more easily or more reliably. The beam B1 and the beam B2 may be separated from each other with a slight distance.

FIG. 8 is a plan view of the welded structure 10-1 (10) as an example, and FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. In the welded structure 10-1, a welded portion 14 extending in an annular shape along the boundary BL1 is formed. Further, the welded portion 14 extends along a corner portion between the boundary BL1 and the boundary BL2. The depth direction of the welded portion 14 is the opposite direction to the Z direction, and the extending direction of the welded portion 14 is the circumferential direction of the protrusion 12b.

10 is a plan view of the welded structure 10-2 (10) as an example, and FIG. 11 is a cross-sectional view taken along the line XI-XI of FIG. In the welded structure 10-2, a welded portion 14 extending in an arc shape along the boundary BL2 is formed. Further, the welded portion 14 extends along the corner portion between the outer peripheral surface and the end surface 12a of the metal conductor 11, in other words, along the radial outer edge of the boundary BL2. The depth direction of the welded portion 14 is the direction between the opposite direction of the Z direction and the radial inward direction of the protrusion 12b, and the extending direction of the welded portion 14 is the circumferential direction of the protrusion 12b.

FIG. 12 is a plan view of the welded structure 10-3 (10) as an example, and FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. In the welded structure 10-3, a welded portion 14 is formed which penetrates the metal conductor 11 and straddles the boundary BL2 in the Z direction. The welded portion 14 extends from the metal conductor 11 to the metal conductor 12. Further, the welded portion 14 extends in an annular shape at the center of the annular portion of the metal conductor 11 in the width direction. The depth direction of the welded portion 14 is the opposite direction to the Z direction, and the extending direction of the welded portion 14 is the circumferential direction of the protrusion 12b.

FIG. 14 is a plan view of the welded structure 10-4 (10) as an example. Also in the welded structure 10-4, as in FIG. 12, a welded portion 14 that penetrates the metal conductor 11 and straddles the boundary BL2 in the Z direction is formed. Further, the welded portion 14 straddles the annular boundary BL2 in a direction intersecting the circumferential direction of the annular shape (Y direction in FIG. 14). The depth direction of the welded portion 14 is the opposite direction to the Z direction, and the extending direction of the welded portion 14 is the Y direction.

FIG. 15 is a cross-sectional view of the welded structure 10-5 (10) as an example at a position equivalent to that of FIG. In the welded structure 10-5, the welded portion 14 extends in an annular shape along both the boundaries BL1 and BL2. Further, the welded portion 14 extends along a corner portion between the boundary BL1 and the boundary BL2. The depth direction of the welded portion 14 is the direction between the opposite direction of the Z direction and the radial outer direction of the protrusion 12b, and the extension direction of the welded portion 14 is the circumferential direction of the protrusion 12b.

Further, in the example of FIG. 15, the welded portion 14 does not pass through the end face of the metal conductor 11 in the Z direction. As described above, even if the welded portion 14 is not formed on the surface of the metal conductor 11, the end face is irradiated with the second laser beam, and the heated state of the end face exceeds the melting point of the metal which is a component of the plating layer. If obtained, it may be possible to remove the plating layer on the end face. That is, the plating layer may be removed even in a portion away from the region where the welded portion 14 is formed, in other words, a portion separated from the exposed portion of the weld metal 14a. According to such a method, it is possible to more reliably suppress the mixing of metal, which is a component of the plating layer, into the welded portion 14.

As described above, in the present embodiment, for example, a welded portion 14 for joining a plurality of metal conductors 11 and 12 including a metal conductor on which a plating layer is formed is formed by irradiation with a laser beam L, and the laser is formed. The light L includes a beam B1 having a wavelength of 800 [nm] or more and 1200 [nm] or less and a beam B2 having a wavelength of 500 [nm] or less, and a plurality of metal conductors are provided by a second laser beam forming the beam B2. The plating layer formed on at least one of 11 and 12 is removed.

Further, in the present embodiment, for example, the wavelength of the second laser beam is 400 [nm] or more and 500 [nm] or less.

According to such a method, for example, the plating layer can be removed by the second laser beam, so that the metal which is a component of the plating layer is mixed in the welded portion 14 and the bonding strength of the welded portion 14 is lowered. Can be suppressed. Further, since it is not necessary to remove the plating layer by separately irradiating a pulse laser before welding, the processing time can be shortened, and the labor and cost of processing can be further reduced. Further, by irradiating the laser beam L forming the beams B1 and B2, there is an advantage that higher quality welding with less spatter and blow holes can be performed.

Further, in the present embodiment, for example, the laser beam L including the first laser beam and the second laser beam is swept in the sweep direction SD on the surface Wa, and the welded portion 14 is moved in the X direction along the surface Wa. It extends along.

Further, in the present embodiment, for example, on the surface Wa, at least a part of the beam B2 (second spot) of the second laser beam has a sweep direction SD more than the beam B1 (first spot) of the first laser beam. It is located in front.

Further, in the present embodiment, for example, the beam B1 and the beam B2 partially overlap each other on the surface Wa.

Further, in the present embodiment, for example, on the surface Wa, the beam B2 is wider than the beam B1.

Further, in the present embodiment, for example, on the surface Wa, the outer edge B2a (second outer edge) of the beam B2 surrounds the outer edge B1a (first outer edge) of the beam B1.

As described above, the inventors have confirmed that welding defects can be further reduced in welding by irradiation with laser light L forming such beams B1 and B2 on the surface Wa. This is because, as described above, the processing target W is preheated by the region B2f of the beam B2 before the beam B1 arrives, so that the molten pool of the processing target W formed by the beam B2 and the beam B1 is further formed. It can be presumed that this is for stabilization. Therefore, according to the laser beam L having such beams B1 and B2, for example, welding with less welding defects and higher welding quality can be performed. Further, according to such settings of the beams B1 and B2, there is an advantage that, for example, the power of the first laser beam can be further lowered. Further, when the beam B1 and the beam B2 are irradiated coaxially, there is an advantage that the relative rotation between the optical head 120 and the processing target W becomes unnecessary.

Further, in the present embodiment, for example, at least one of the plurality of metal conductors 11 and 12 is made of a copper-based material, and the plating layer is, for example, a tin plating layer. The effect of this embodiment is obtained in the case of such a configuration.

[Second Embodiment]
FIG. 16 is a schematic configuration diagram of the laser welding apparatus 100A of the second embodiment. As shown in FIG. 16, in the present embodiment, the drive mechanism 150 moves the processing target W relative to the optical head 120, so that the laser beam L emitted from the optical head 120 is radiated on the surface Wa. Sweep with. The operation of the drive mechanism 150 is controlled by the controller 141. In this case, in order to sweep the laser beam L on the surface Wa in the sweep direction SD, the drive mechanism 150 moves the processing target W with respect to the optical head 120 in the direction opposite to the sweep direction SD.

Further, also in the present embodiment, the controller 141 can control the drive mechanism 150 so as to detect the deviation of the spot with respect to the predetermined position from the image captured by the camera 170 and correct the deviation. Further, the controller 141 may execute feedback control so that the deviation is within a predetermined threshold value. The controller 141 and the drive mechanism 150 are examples of the correction mechanism. With such a configuration, the accuracy of the irradiation position of the laser beam can be improved.

The same effect as that of the first embodiment can be obtained by this embodiment as well.

[Third Embodiment]
FIG. 17 is a schematic configuration diagram of the laser welding apparatus 100B of the third embodiment. As shown in FIG. 17, in this embodiment, the optical head 120 has a galvano scanner 126 between the filter 124 and the condenser lens 122. Except for this point, the laser welding apparatus 100B has the same configuration as the laser welding apparatus 100 of the first embodiment.

The galvano scanner 126 has two mirrors 126a and 126b, and by controlling the angles of the two mirrors 126a and 126b, the irradiation position of the laser beam L can be set without moving the optical head 120. It is a device that can be moved to sweep the laser beam L. The angles of the mirrors 126a and 126b are changed by, for example, a motor (not shown) controlled by the controller 141, respectively. With such a configuration, a mechanism for relatively moving the optical head 120 and the processing target W becomes unnecessary, and for example, there is an advantage that the device configuration can be miniaturized.

Further, also in the present embodiment, the controller 141 can control the galvano scanner 126 so as to detect a deviation of the spot with respect to a predetermined position from the image captured by the camera 170 and correct the deviation. Further, the controller 141 may execute feedback control so that the deviation is within a predetermined threshold value. The controller 141 and the galvano scanner 126 are examples of the correction mechanism. With such a configuration, the accuracy of the irradiation position of the laser beam can be improved.

Although the embodiments of the present invention have been exemplified above, the above-described embodiment is an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in various other embodiments, and various omissions, replacements, combinations, and changes can be made without departing from the gist of the invention. In addition, specifications such as each configuration and shape (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) are changed as appropriate. Can be carried out.

For example, the number of metal conductors may be 3 or more, and in that case, the number of metal conductors on which the plating layer is formed is 1 or more.

Further, when the laser beam is swept to the object to be processed, the surface area of the molten pool may be adjusted by sweeping by known wobbling, weaving, output modulation or the like.

10,10-1 to 10-5 ... Welded structure 11 ... Metal conductor (first metal conductor)
11a ... Through hole 12 ... Metal conductor (first metal conductor)
12a ... End face 12b ... Protrusion 14 ... Welded part 14a ... Welded metal 14a1 ... First part 14a2 ... Second part 14b ... Heat-affected zone 100, 100A, 100B ... Laser welding device (welding device)
111 ... Laser device (laser oscillator)
112 ... Laser device (laser oscillator)
120 ... Optical head 121, 121-1, 121-2 ... Collimating lens 122 ... Condensing lens 123 ... Mirror 124 ... Filter 125 ... DOE (diffractive optical element)
125a ... Diffraction grating 126 ... Galvano scanner 126a, 126b ... Mirror 127 ... Filter 128 ... Mirror 130 ... Optical fiber 141 ... Controller (detection mechanism, correction mechanism)
150 ... Drive mechanism (correction mechanism)
170 ... Camera (detection mechanism)
A ... Crystal grain B1 ... Beam (first spot)
B1a ... Outer edge B2 ... Beam (second spot)
B2a ... Outer edge B2b ... Region B2f ... Region BL1, BL2 ... Boundary C ... Center point D1 ... Spot diameter (outer diameter)
D2 ... Spot diameter (outer diameter)
D _n ... Spot diameter d ... Depth E _n , E ₁ , E ₂ ... Energy density I ... Region L ... Laser light Pd 1, Pd 2 ... Power density P _n ... Power SD ... Sweeping direction T ... (Laser light is irradiated. (Metal conductor) Thickness Ta ... (Processing target) Thickness V ... Sweeping speed W ... Processing target Wa ... Surface wb ... Width X ... Direction Y ... Direction Z ... Direction Z1 ... First Area Z2 ... Second area

Claims (21)

It is a welding method in which a surface of a processing target, which is a plurality of metal conductors including at least one metal conductor on which a plating layer is formed, is irradiated with a laser beam and welded.
The laser light includes a first laser light having a wavelength of 800 [nm] or more and 1200 [nm] or less, and a second laser light having a wavelength of 500 [nm] or less.
A welding method for removing the plating layer by irradiation with the second laser beam. The welding method according to claim 1, wherein the wavelength of the second laser beam is 400 [nm] or more and 500 [nm] or less. The welding method according to claim 1 or 2, wherein the melting point of the plating layer is lower than the melting point of the plurality of metal conductors. The welding method according to any one of claims 1 to 3, wherein at least one of the plurality of metal conductors is made of a copper-based material. The laser beam is swept in the sweep direction on the surface of the laser beam.
On the surface, at least a part of the second spot formed on the surface by the second laser beam is in front of the first spot formed on the surface by the first laser beam in the sweep direction. The welding method according to any one of claims 1 to 4, which is located in. The welding method according to claim 5, wherein the first spot and the second spot overlap at least partially on the surface. The welding method according to claim 5, wherein on the surface, the second outer edge of the second spot surrounds the first outer edge of the first spot. Any one of claims 1 to 7, wherein the power density of the second laser beam is 0.16 [MW / cm ² ] or more and 1.5 [MW / cm ² ] or less on the surface. The welding method described in. Among the plurality of metal conductors, the thickness of the metal conductor having the surface is 0.5 [mm] or more and less than 1 [mm].
When the surface of the surface is a plane perpendicular to the laser beam due to the first laser beam, the spot diameter of the first spot formed on the plane is 20 [μm] or more and 80 [μm] or less.
The power of the first laser beam is 0.3 [kW] or more and 6 [kW] or less.
When the surface of the surface is a plane perpendicular to the laser beam due to the second laser beam, the spot diameter of the first spot formed on the plane is 50 [μm] or more and 400 [μm] or less.
The welding method according to any one of claims 1 to 8, wherein the power of the second laser beam is 0.05 [kW] or more and 1 [kW] or less. The energy density of the first laser beam per unit volume of the laser beam in the welded portion of the plurality of metal conductors is 200 [J / mm ³ ] or more.
Claims 1 to 9 that the energy density of the second laser beam per unit volume in the irradiation direction of the laser beam in the welded portion is 5 [J / mm ³ ] or more and 49 [J / mm ³ ] or less. The welding method described in any one of them. Laser oscillator and
An optical head that irradiates a plurality of metal conductors including at least one metal conductor on which a plating layer is formed with a laser beam from the laser oscillator.
A welding device that welds the plurality of metal conductors.
The laser light includes a first laser light having a wavelength of 800 [nm] or more and 1200 [nm] or less, and a second laser light having a wavelength of 500 [nm] or less.
A welding device that removes the plating layer by irradiation with the second laser beam. The welding apparatus according to claim 11, further comprising a beam shaper that divides the laser beam into a plurality of beams. The welding apparatus according to claim 11 or 12, further comprising a galvano scanner that changes the irradiation direction of the laser beam so as to sweep the laser beam in the sweep direction on the surface. A detection mechanism that detects deviations of spots formed on the surface by the laser beam from a predetermined position, and
A correction mechanism that corrects the deviation and
The welding apparatus according to any one of claims 11 to 13. The welding device according to claim 14, wherein the correction mechanism changes the relative positions of the plurality of metal conductors and the optical head. The welding apparatus according to claim 14, wherein the correction mechanism includes a galvano scanner that changes the irradiation direction of the laser beam so as to sweep the laser beam in the sweep direction on the surface. A plurality of metal conductors including at least one first metal conductor on which a plating layer is formed, and
A welded portion obtained by welding a plurality of metal conductors, and a welded portion.
It is a welded structure of a metal conductor equipped with
The welded portion includes a welded metal extending from the surface of the welded structure of the metal conductor in a direction intersecting the surface, and a heat-affected zone located around the welded metal.
Have,
The weld metal is a weld of a metal conductor having a first portion and a second portion in which the average cross-sectional area of crystal grains in a cross section along a direction intersecting the surface is larger than that of the first portion. Construction. The welded structure of a metal conductor according to claim 17, wherein the weld portion extends along the surface. The welded structure of a metal conductor according to claim 17 or 18, wherein the weld portion penetrates the first metal conductor and extends from the first metal conductor to another metal conductor. The metal conductor according to any one of claims 17 to 19, wherein the weld extends along a boundary between the first metal conductor and another metal conductor adjacent to the first metal conductor. Welding structure. The metal according to any one of claims 17 to 20, wherein the weld portion extends so as to straddle a boundary between the first metal conductor and another metal conductor adjacent to the first metal conductor. Welded structure of conductor.

Images