Welding method and welding equipment

Abstract

To provide a new welding method and a welding device, which can weld a plurality of overlapped members for instance, as well as a product which is welded by the welding method or the welding device.SOLUTION: In a welding method, for instance an end part in which edges extending in a second direction crossing a first direction of a plurality of members overlapped in the first direction are lined in the first direction are irradiated with laser light emitted from a laser oscillator including fiber laser, along a third direction crossing the first direction and the second direction from the outsides of the end parts, so as to weld the edges lined adjacent to each other in the first direction to each other, where a wavelength of laser light is set to be 380[nm] or more and 1200[nm] or less. Further laser light includes for instance first laser light with wavelengths of 800 [nm] or more and 1200 [nm] or less and second laser light with wavelengths of 500 [nm] or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a welding method. and Welding Equipment Place Regarding. [Background technology]

[0002] Conventionally, a vapor chamber has been known in which a chamber for containing a refrigerant is provided between two stacked plate-shaped metal members, and the refrigerant is sealed by welding the peripheral edges of the two metal members (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-35348 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the vapor chamber of Patent Document 1, two plate-shaped members are joined by irradiating them with a laser beam along the stacking direction. In such a configuration, for example, a flange is provided that projects in the extension direction of the plate-shaped members, which is the width direction of the welded portion, and this causes a problem that the metal members and therefore the vapor chamber tend to become large in the extension direction of the plate-shaped members.

[0005] On the other hand, in a vapor chamber in which two plate-shaped members are welded together by irradiating a laser beam toward the boundary between the two plate-shaped members along the direction in which the plate-shaped members extend, the width of the welded portion spreads in the direction in which the plate-shaped members are stacked. In this case, for example, it is difficult to apply the method to thin plate thicknesses, and if the weld width is adjusted to the plate thickness, the weld depth is also short, making it difficult to ensure the required weld strength.

[0006] Therefore, one object of the present invention is to provide a new and improved welding method and welding apparatus capable of welding, for example, multiple overlapping members, as well as a product welded by said welding method or said welding apparatus. [Means for solving the problem]

[0007] In the welding method of the present invention, for example, laser light emitted from a laser oscillator including a fiber laser is irradiated from the outside of each end portion of a plurality of components overlapping in a first direction, the ends of which extend in a second direction intersecting the first direction, the ends being aligned in the first direction, along a third direction intersecting the first and second directions, thereby welding the ends adjacent to each other in the first direction, and the wavelength of the laser light is 380 nm or more and 1200 nm or less.

[0008] In the welding method, for example, 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.

[0009] In the welding method, for example, the second laser light has a wavelength of not less than 400 [nm] and not more than 500 [nm].

[0010] In the welding method, for example, the second laser light is irradiated in the first direction so as to span a gap at a boundary between the edges adjacent in the first direction.

[0011] In the welding method, for example, the laser light is swept in a sweep direction along the second direction on a surface of the end portion extending in the first direction and the second direction, and at least a portion of a second spot formed on the surface by the second laser light is located forward in the sweep direction of a first spot formed on the surface by the first laser light.

[0012] In the welding method, for example, the first spot and the second spot at least partially overlap on the surface.

[0013] In the welding method, for example, on the surface, a second outer edge of the second spot surrounds a first outer edge of the first spot.

[0014] In the welding method, for example, each of the plurality of members is made of any one of a copper-based metal material, an aluminum-based metal material, a nickel-based metal material, an iron-based metal material, and a titanium-based metal material.

[0015] The welding device of the present invention includes, for example, a laser oscillator including a fiber laser, and an optical head which irradiates laser light emitted from the laser oscillator to ends of a plurality of components overlapping in a first direction, the ends extending in a second direction intersecting the first direction, where the ends are aligned in the first direction, from the outside of the ends along a third direction intersecting the first and second directions, and which welds the ends adjacent to each other in the first direction, and the wavelength of the laser light is 380 nm or more and 1200 nm or less.

[0016] The welding device includes, for example, a beam shaper that splits the laser light into a plurality of beams.

[0017] The welding apparatus, for example, includes a galvanometer scanner that changes the emission direction of the laser light so that the laser light moves in a sweeping direction along the second direction on a surface of the end portion extending in the first direction and the second direction.

[0018] The welding device may, for example, include a rotation mechanism that rotates the end portion about a rotation axis aligned along the first direction.

[0019] The welding device includes, for example, a detection mechanism that detects a deviation of a spot formed on the surface by the laser light from a predetermined position, and a correction mechanism that corrects the deviation.

[0020] The product of the present invention, for example, includes a plurality of members, each having an edge extending in a second direction, overlapping in a first direction with the edges lined up in the first direction intersecting the second direction, and a welded portion formed by welding the edges of adjacent members of the plurality of members in the first direction, the welded portion having a weld metal extending from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction to a third direction intersecting the first direction and the second direction, and a heat-affected zone positioned around the weld metal, and the weld metal having a first portion and a second portion in which the average cross-sectional area of ​​crystal grains in a cross section intersecting the second direction is larger than that of the first portion.

[0021] In the product, for example, the average cross-sectional area of ​​the crystal grains contained in the second portion is 1.8 times or more the average cross-sectional area of ​​the crystal grains contained in the first portion.

[0022] In the product, for example, the weld metal extends in the second direction.

[0023] In the product, for example, the aspect ratio of the weld metal's depth in the third direction to its width in the first direction is 1 or more and 5 or less.

[0024] In the product, for example, the aspect ratio is 1.5 or more and 5 or less.

[0025] The product includes, for example, a first member and a second member joined to the first member while forming a space between the first member and a second member, and the first member and the second member are joined as the multiple members by the welds.

[0026] The product may, for example, comprise a first member and a second member indirectly joined to the first member via a third member with a space formed between the first member and a third member, and at least one of the first member and the third member, and the second member and the third member, are joined as the plurality of members by the welded portion.

[0027] The product may, for example, include a fluid medium contained within the space, and the plurality of components may be welded together in a manner that prevents leakage of the fluid medium from the weld to outside the space.

[0028] The product of the present invention, for example, comprises a plurality of members each having an edge extending in a second direction and overlapping in a first direction with the edges aligned in a first direction intersecting the second direction, and a welded portion formed by welding the edges of adjacent members among the plurality of members in the first direction together, wherein the welded portion extends in the second direction and is exposed with a gap from both ends of the end in the first direction when the end is viewed from outside the end along a third direction intersecting the first direction and the second direction.

[0029] In the product, for example, the weld has a weld metal extending from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction to a third direction intersecting the first direction and the second direction, and a heat-affected zone positioned around the weld metal, and the aspect ratio of the depth of the weld metal in the third direction to the width in the first direction is greater than or equal to 1 and less than 5.

[0030] In the product, for example, the aspect ratio is 1.5 or more and 5 or less. Effect of the Invention

[0031] According to the present invention, for example, a new and improved welding method and welding apparatus capable of welding a plurality of overlapping members can be provided, as well as a product welded by the welding method or welding apparatus. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is an exemplary schematic configuration diagram of a laser welding device according to a first embodiment. [Diagram 2]FIG. 2 is a schematic side view showing an example of a holding mechanism for an object to be processed that is included in the laser welding apparatus of the first embodiment. [Diagram 3] FIG. 3 is a schematic plan view showing an example of a holding mechanism for an object to be processed that is included in the laser welding apparatus of the first embodiment. [Figure 4] FIG. 4 is an exemplary schematic diagram showing a beam (spot) of laser light formed on the surface of an object to be processed by the laser welding apparatus of the first embodiment. [Diagram 5] FIG. 5 is a graph showing the light absorptance of each metal material versus the wavelength of the irradiated laser light. [Figure 6] FIG. 6 is an exemplary schematic cross-sectional view of a welded portion according to an embodiment. [Figure 7] FIG. 7 is an exemplary schematic cross-sectional view showing a part of a welded portion of the embodiment. [Figure 8] FIG. 8 is a schematic side view showing an example of a holding mechanism for an object to be processed that is included in the laser welding apparatus of the first embodiment. [Figure 9] FIG. 9 is an exemplary schematic configuration diagram of the laser welding device according to the second embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing the concept of the principle of the diffractive optical element included in the laser welding apparatus of the second embodiment. [Figure 11] FIG. 11 is an exemplary schematic configuration diagram of a laser welding device according to the third embodiment. [Figure 12] FIG. 12 is an exemplary schematic configuration diagram of a laser welding device according to the fourth embodiment. [Figure 13] FIG. 13 is an exemplary schematic configuration diagram of a laser welding device according to the fifth embodiment. [Figure 14] FIG. 14 is a schematic diagram showing an example of a laser light beam (spot) formed on the surface of the object to be processed by the laser welding device of the fifth embodiment. [Figure 15] FIG. 15 is a schematic diagram showing an example of a laser light beam (spot) formed on the surface of the object to be processed by the laser welding device of the fifth embodiment. [Figure 16]FIG. 16 is an exemplary schematic perspective view of a product according to the sixth embodiment. [Figure 17] FIG. 17 is a cross-sectional view taken along line XVII-XVII of FIG. [Figure 18] FIG. 18 is an illustrative schematic cross-sectional view of a product according to a first modified example of the sixth embodiment. [Figure 19] FIG. 19 is an illustrative schematic cross-sectional view of a product according to a second modified example of the sixth embodiment. [Figure 20] FIG. 20 is an illustrative schematic cross-sectional view of a product according to a third modified example of the sixth embodiment. [Figure 21] FIG. 21 is an illustrative schematic exploded perspective view of a product according to a fourth modified example of the sixth embodiment. [Figure 22] FIG. 22 is an illustrative schematic cross-sectional view of a product according to a fourth modified example of the sixth embodiment. [Diagram 23] FIG. 23 is an exemplary schematic configuration diagram of a laser welding device according to the seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Exemplary embodiments and modifications of the present invention are disclosed below. The configurations of the embodiments and modifications shown below, as well as the actions and results (effects) brought about by the configurations, are merely examples. The present invention can be realized by configurations other than those disclosed in the following embodiments and modifications. 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.

[0034] The embodiments and modifications shown below have similar configurations. Therefore, according to the configurations of the embodiments and modifications, similar actions and effects based on the similar configurations can be obtained. In the following, the similar configurations are given the same reference numerals, and duplicated descriptions may be omitted.

[0035] In each drawing, 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 direction, Y direction, and Z direction intersect each other and are perpendicular to each other. The X direction is the sweep direction SD and also the extension direction (longitudinal direction) of the welded portion 14. The Y direction is the stacking direction and also the width direction (short direction) of the welded portion 14. The Z direction is the normal direction of the surface Wa (machined surface, welded surface) of the processing object (welded object).

[0036] In addition, in this specification, ordinal numbers are given for the sake of convenience to distinguish between parts, members, parts, laser beams, directions, etc., and do not indicate priority or order.

[0037] [First embodiment] Fig. 1 is a schematic configuration diagram of a laser welding apparatus 100 according to the first embodiment. As shown in Fig. 1, the laser welding apparatus 100 includes a laser device 111, a laser device 112, an optical head 120, and an optical fiber 130. The laser welding apparatus 100 is an example of a welding apparatus.

[0038] The laser devices 111 and 112 each have a laser oscillator and are configured to be able to output laser light with a power of, for example, several kW. The laser devices 111 and 112 emit laser light with a wavelength of 380 [nm] or more and 1200 [nm] or less. The laser devices 111 and 112 each have a laser light source therein, such as a fiber laser, a semiconductor laser (element), a YAG laser, or a disk laser. The laser devices 111 and 112 may be configured to output multi-mode laser light with a power of several kW as the sum of the outputs of the multiple light sources.

[0039] The laser device 111 outputs a first laser light having a wavelength of 800 [nm] or more and 1200 [nm] or less. The laser device 111 is an example of a first laser device. As an example, the laser device 111 has a fiber laser or a semiconductor laser (element) as a laser light source. The laser oscillator of the laser device 111 is an example of a first laser oscillator.

[0040] On the other hand, the laser device 112 outputs a second laser light 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. It is preferable that the laser device 112 outputs a second laser light having a wavelength of 400 [nm] or more and 500 [nm] or less. The laser oscillator of the laser device 112 is an example of a second laser oscillator.

[0041] The optical fibers 130 guide the laser beams output from the laser devices 111 and 112 to the optical head 120 .

[0042] The optical head 120 is an optical device for irradiating a processing object with the laser light input from the laser devices 111 and 112. The optical head 120 includes a collimator lens 121, a condenser lens 122, a mirror 123, and a filter 124. The collimator lens 121, the condenser lens 122, the mirror 123, and the filter 124 may also be referred to as optical components.

[0043] The optical head 120 is configured to be able to change its relative position with respect to the object to be processed in order to sweep the laser light L while irradiating the laser light L on the surface Wa of the end portion 10a as the object to be processed. The relative movement between the optical head 120 and the object to be processed can be realized by moving the optical head 120, moving the object to be processed, or moving both the optical head 120 and the object to be processed.

[0044] The optical head 120 may be configured to have a galvano scanner (not shown) or the like so as to be capable of sweeping the laser light L over the surface Wa.

[0045] The collimating lenses 121 (121-1, 121-2) each collimate the laser light input via the optical fiber 130. The collimated laser light becomes parallel light.

[0046] The mirror 123 reflects the first laser light that has been collimated by the collimator lens 121-1. The first laser light reflected by the mirror 123 travels in the opposite Z direction toward the filter 124. Note that in a configuration in which the first laser light is input to the optical head 120 so as to travel in the opposite Z direction, the mirror 123 is not necessary.

[0047] Filter 124 is a high-pass filter that transmits the first laser light and reflects but does not transmit the second laser light. The first laser light passes through filter 124 and travels in the opposite Z direction toward condenser lens 122. On the other hand, filter 124 reflects the second laser light that has been collimated by collimator lens 121-2. The second laser light reflected by filter 124 travels in the opposite Z direction toward condenser lens 122.

[0048] The condenser lens 122 condenses the first laser light and the second laser light as parallel light, and irradiates the resultant laser light L (output light) onto the processing target.

[0049] The processing object is a laminate 10 in which a first member 11 and a second member 12 are stacked in the Y direction. The laminate 10 has the first member 11, the second member 12, and a welded portion 14 in which the first member 11 and the second member 12 are welded. The laminate 10 becomes a product by welding the first member 11 and the second member 12 by the welded portion 14. The first member 11 and the second member 12 each have a plate-like shape that spreads across the Y direction. The portions of the first member 11 and the second member 12 that are welded by the welded portion 14 extend in the X direction and the Z direction, respectively. The first member 11 and the second member 12 can also be referred to as plate-like members. The Y direction is an example of a first direction. The first member 11 and the second member 12 are an example of a plurality of members.

[0050] The end 10a of the laminate 10 has edges 11a and 12a. The edge 11a includes an edge 11a of the first member 11 and an edge 12a of the second member 12. The edges 11a and 12a each extend in the X direction. The edges 11a and 12a may also be referred to as end faces. The edges 11a and 12a are aligned in the Y direction. The edges 11a and 12a are substantially flush with each other, but may have some steps. The edges 11a and 12a form a surface Wa of the end 10a that faces the optical head 120. The X direction is an example of a second direction.

[0051] The laser light L is irradiated from the outside of the end portion 10a toward the boundary between the end edge 11a and the end edge 12a in the opposite direction to the Z direction. As a result, a welded portion 14 is formed in the end portion 10a, extending from the surface Wa along the boundary in the opposite direction to the Z direction. That is, the welded portion 14 joins the end edge 11a and the end edge 12a. The welded portion 14 also extends linearly in the sweep direction SD (X direction) along the surface Wa by sweeping the laser light L in the sweep direction SD relative to the surface Wa. The Z direction is an example of a third direction.

[0052] Fig. 2 is a side view of the holding mechanism 150 of the laminate 10, and Fig. 3 is a plan view of the holding mechanism 150. As shown in Figs. 2 and 3, the holding mechanism 150 has a pressing member 151 and support members 152 and 153.

[0053] The pressing member 151 is, for example, a plate-shaped member that spreads across the Z direction, and is made of, for example, a metal material with relatively high thermal conductivity. The two pressing members 151 are arranged to sandwich the stack 10 in the Y direction. The support members 152 and 153 are arranged to sandwich the pressing member 151 in the Z direction and hold the pressing member 151. The support members 152 and 153 hold the two pressing members 151 so that a force is applied from the two pressing members 151 to the stack 10 from both sides in the Y direction, causing the first member 11 and the second member 12 to approach each other in the Y direction. That is, by adjusting the positions of the pressing members 151 and the support members 152 and 153 in the holding mechanism 150, the stack 10 can be set in an appropriate position and posture with respect to the laser light L.

[0054] Also, as shown in FIG. 2, in this embodiment, when the laminate 10 is viewed in the opposite direction to the Z direction, i.e., when viewed along the Z direction from the outside of the end portion 10a, the welded portion 14 is exposed at a distance from the ends 10a1 on both sides in the Y direction of the end portion 10a, and does not reach both end faces of the laminate 10 in the Y direction.

[0055] FIG. 4 is a schematic diagram showing a beam (spot) of laser light L irradiated onto a surface Wa. Each of beams B1 and B2 has, for example, a Gaussian-shaped power distribution in the radial direction of a cross section perpendicular to the optical axis direction of the beam. However, the power distribution of beams B1 and B2 is not limited to a Gaussian shape. In addition, in each diagram in which each beam B1, B2 is represented by a circle as in FIG. 4, the diameter of the circle representing beams B1, B2 is the beam diameter of each beam B1, B2. The beam diameter of each beam B1, B2 includes the peak of the beam and is 1 / e of the peak intensity. 2 In the case of a non-circular beam (not shown), the diameter of the region with an intensity of 1 / e of the peak intensity in the direction perpendicular to the sweep direction SD is defined as the diameter of the region with an intensity of 1 / e 2 The length of the region where the intensity is equal to or greater than this can be defined as the beam diameter. The beam diameter on the surface Wa is called the spot diameter.

[0056] 4, in this embodiment, as an example, the beam of laser light L is formed such that a beam B1 of the first laser light and a beam B2 of the second laser light overlap on the surface Wa, the beam B2 is larger (wider) than the beam B1, and 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 a first spot, and the beam B2 is an example of a second spot.

[0057] 4, the beam (spot) of the laser light L on the surface Wa has a point-symmetric shape with respect to the center point C, so the shape of the spot is the same for any sweep direction SD. Therefore, when a moving mechanism for relatively moving the optical head 120 and the processing target is provided to sweep the laser light L on the surface Wa, the moving mechanism may have at least a mechanism capable of relatively translating, and a mechanism capable of relatively rotating may be omitted.

[0058] When a gap (not shown) at the boundary Br between the first member 11 and the second member 12, where the edges 11a, 12a are slightly spaced apart from each other in the Y direction, is present, the laser beam L is irradiated so as to span the gap. As an example, the laser welding apparatus 100 and the laminate 10 are set so that the beam B2 of the second laser beam spans the gap in the Y direction on the surface Wa. In this case, the width of the spot of the second laser beam (for example, the spot diameter D2 in FIG. 4) is larger than the width of the gap.

[0059] The first member 11 and the second member 12 as the processing objects can each be made of a metal material with a relatively high thermal conductivity. The metal material can be, for example, a copper-based metal material, an aluminum-based metal material, a nickel-based metal material, an iron-based metal material, a titanium-based metal material, or the like, specifically, copper, a copper alloy, aluminum, an aluminum alloy, tin, nickel, a nickel alloy, iron, stainless steel, titanium, a titanium alloy, or the like. The first member 11 and the second member 12 can be made of the same material or different materials.

[0060] [Wavelength and light absorption rate] Here, the light absorptance of metal materials will be explained. Fig. 5 is a graph showing the light absorptance of each metal material versus the wavelength of the irradiated laser light L. The horizontal axis of the graph in Fig. 5 is the wavelength, and the vertical axis is the absorptance. Fig. 5 shows the relationship between wavelength and absorptance for aluminum (Al), copper (Cu), gold (Au), nickel (Ni), silver (Ag), tantalum (Ta), and titanium (Ti).

[0061] Although the characteristics differ depending on the material, it can be seen that for each metal shown in Figure 5, the energy absorption rate is higher when using blue or green laser light (second laser light) than when using general infrared (IR) laser light (first laser light). This characteristic is prominent in copper (Cu), gold (Au), etc.

[0062] When a laser beam is irradiated onto a workpiece that has a relatively low absorption rate for the wavelength used, most of the light energy is reflected and does not affect the workpiece as heat. Therefore, a relatively high power is required to obtain a melted region of sufficient depth. In this case, the center of the beam is suddenly energized, causing sublimation and forming a keyhole.

[0063] On the other hand, when a laser beam is irradiated onto a workpiece having a relatively high absorptivity for the wavelength used, most of the input energy is absorbed by the workpiece and converted into thermal energy. In other words, since there is no need to apply excessive power, no keyhole is formed and the workpiece melts by thermal conduction.

[0064] In this embodiment, the wavelength of the first laser light, the wavelength of the second laser light, and the material of the object to be processed are selected so that the absorptance of the second laser light by the object to be processed is higher than the absorptance of the first laser light. In this case, when the sweep direction is the sweep direction SD shown in Fig. 5, the second laser light is first irradiated to the part to be welded (hereinafter referred to as the welded part) of the object to be processed by sweeping the spot of the laser light L by the region B2f of the beam B2 of the second laser light located in front of SD in Fig. 5. Then, the welded part is irradiated with the beam B1 of the first laser light, and then the second laser light is irradiated again by the region B2b of the beam B2 of the second laser light located behind the sweep direction SD.

[0065] Therefore, a thermal conduction type melting region is first generated in the welded portion by irradiation of the second laser light having a high absorptivity in the region B2f. Then, a deeper keyhole type melting region is generated in the welded portion by irradiation of the first laser light. In this case, since a thermal conduction type melting region is formed in advance in the welded portion, a melting region of a required depth can be formed by a first laser light having a lower power than when the thermal conduction type melting region is not formed. Then, the melted state of the welded portion is changed by irradiation of the second laser light having a high absorptivity in the region B2b.

[0066] Furthermore, experimental research by the inventors has confirmed that welding defects such as spatters and blowholes can be reduced in welding by irradiation of the laser light L of the beam as shown in Fig. 4. This is presumably because the molten pool of the workpiece formed by the beam B2 and the beam B1 becomes more stable by preheating the workpiece by the region B2f of the beam B2 before the arrival of the beam B1.

[0067] [Welding method] In welding using the laser welding device 100, first, the laminate 10 is set in the holding mechanism 150 so that the laser light L is irradiated onto the surface Wa. Then, while the laser light L including the beam B1 and the beam B2 is irradiated onto the surface Wa, the laser light L and the laminate 10 (holding mechanism 150) are moved relative to each other. As a result, the laser light L moves (sweeps) on the surface Wa in the sweep direction SD while being irradiated onto the surface Wa. The portion irradiated with the laser light L melts and then solidifies as the temperature drops, thereby welding the first member 11 and the second member 12 together and integrating the laminate 10.

[0068] [Weld cross section] FIG. 6 is a cross-sectional view of a weld 14 formed on a workpiece W. FIG. 6 is a cross-sectional view perpendicular to the sweep direction SD (X direction) and along the thickness direction (Z direction). The weld 14 extends in the sweep direction SD, i.e., in a direction perpendicular to the paper surface of FIG. 6. FIG. 6 shows a cross-section of the weld 14 formed on the workpiece W, which is a single copper plate with a thickness of 2 [mm]. It can be assumed that the shape of the weld 14 formed on multiple plate-shaped metal materials stacked in the Y direction is substantially the same as the shape of the weld 14 formed on the workpiece W, which is a single metal material, shown in FIG. 6.

[0069] 6, the welded portion 14 has a weld metal 14a extending from the surface Wa in the opposite direction to the Z direction, and a heat-affected zone 14b located around the welded metal 14a. The welded metal 14a is a portion that is melted by irradiation with laser light L and then solidifies. The welded metal 14a may also be referred to as a molten solidification zone. The heat-affected zone 14b is a portion of the base material to be processed that is thermally affected but is not melted.

[0070] The width of the weld metal 14a in the Y direction becomes narrower as it moves away from the surface Wa. That is, the cross section of the weld metal 14a has a tapered shape that becomes narrower in the opposite direction to the Z direction.

[0071] Further, detailed analysis of the cross section by the inventors revealed that 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.

[0072] The first portion 14a1 is a portion obtained by melting in a keyhole shape by irradiation with the first laser light, and the second portion 14a2 is a portion obtained by melting by irradiation with a region B2b located behind the second laser light beam B2 in the sweep direction SD. Analysis by the electron back scattered diffraction pattern (EBSD) method revealed that the sizes of the crystal grains in the first portion 14a1 and the second portion 14a2 are different, and specifically, in a cross section perpendicular to the X direction (sweep direction SD), the average value of the cross-sectional area of ​​the crystal grains in the second portion 14a2 is larger than the average value of the cross-sectional area of ​​the crystal grains in the first portion 14a1.

[0073] The inventors confirmed that when only the beam B1 of the first laser light is irradiated to the processing object W, that is, when the region B2b located behind the beam B2 in the sweep direction SD is not irradiated, the second portion 14a2 is not formed, and the first portion 14a1 extends deeply from the surface Wa in the opposite direction to the Z direction. That is, in this embodiment, the second portion 14a2 is formed near the surface Wa by irradiating the region B2b located behind the beam B2 in the sweep direction SD, so that it can be presumed that the first portion 14a1 is formed on the opposite side of the second portion 14a2 to the surface Wa, in other words, at a position away from the surface Wa in the opposite direction to the Z direction.

[0074] FIG. 7 is a cross-sectional view showing a part of the welded portion 14. FIG. 7 shows the boundaries of crystal grains obtained by the EBSD method. In FIG. 7, as an example, crystal grains A having a crystal grain size of 13 μm or less are painted black. Note that 13 μm is not a threshold value of a physical property, but a threshold value set for the analysis of the experimental results. In addition, it is clear from FIG. 7 that crystal grains A are present in a relatively large amount in the first portion 14a1 and in a relatively small amount in the second portion 14a2. That is, the average value of the cross-sectional area of ​​the crystal grains in the second portion 14a2 is larger than the average value of the cross-sectional area of ​​the crystal grains in the first portion 14a1. The inventors confirmed through experimental analysis that the average value of the cross-sectional area of ​​the crystal grains in the second portion 14a2 is 1.8 times or more the average value of the cross-sectional area of ​​the crystal grains in the first portion 14a1.

[0075] As shown in region I in Figure 7, these relatively small crystal grains A are densely packed in a position away from the surface Wa in the Z direction, elongated in the Z direction. Furthermore, analysis of multiple locations at different positions in the X direction (sweep direction SD) confirmed that the region where crystal grains A are densely packed also extends in the sweep direction SD. Because welding is performed while sweeping, it can be assumed that crystals are formed in a similar shape in the sweep direction SD.

[0076] In a case where it is difficult to distinguish the first portion 14a1 and the second portion 14a2 from the appearance or hardness distribution in the cross section, the first region Z1 and the second region Z2, which are geometrically determined from the position and width wb on the surface Wa of the weld metal 14a as shown in Figures 6 and 7, may be the first portion 14a1 and the second portion 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 perpendicular to the sweep direction SD, the second region Z2 is a region from the surface Wa to a depth d in the Z direction, and the first region Z1 can be a region deeper than the depth d, in other words, a region on the opposite side of the surface Wa with respect to the position of the depth d. The width wm can be, for example, 1 / 3 of the width wb (average bead width) on the surface Wa of the weld metal 14a, and the depth d (height, thickness) of the second region Z2 can be, for example, 1 / 2 of the width wb. The depth of the first region Z1 may be, for example, three times the depth d of the second region Z2. The inventors have confirmed through experimental analysis of multiple samples that, in such a setting of the first region Z1 and the second region Z2, the average cross-sectional area of ​​the crystal grains in the second region Z2 is larger than the average cross-sectional area of ​​the crystal grains in the first region Z1, and is at least 1.8 times larger. Such a determination may also be evidence that the first portion 14a1 and the second portion 14a2 are formed in the weld metal 14a by welding.

[0077] In addition, the inventors' experimental research has revealed that the aspect ratio of the weld metal 14a, i.e., the ratio of the depth dm to the width wb at the surface Wa of the weld metal 14a (dm / wb), is preferably 1 or more and 5 or less, and more preferably 1.5 or more and 5 or less, from the standpoint of ensuring the weld strength and suppressing the weld width.

[0078] As described above, in this embodiment, for example, the laser light L emitted from the laser devices 111, 112 (laser oscillators) including fiber lasers is irradiated from the outside of the end portion 10a along the Z direction (opposite to the Z direction) to weld the adjacent end edges 11a, 12a in the Y direction (first direction). The wavelength of the laser light L is 380 [nm] or more and 1200 [nm] or less.

[0079] According to such a configuration and method, for example, it is easy to obtain a weld 14 having a relatively large weld depth relative to the weld width and a required weld strength. In addition, the entrapment of air into the molten metal during welding is suppressed, and welding defects can be reduced.

[0080] In the present embodiment, the laser light L includes, for example, 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.

[0081] In the present embodiment, for example, the wavelength of the second laser light is not less than 400 [nm] and not more than 500 [nm].

[0082] According to such a configuration and method, it is easier to obtain a higher quality weld 14 with fewer welding defects such as spatters and blowholes.

[0083] In this embodiment, for example, if a gap is provided at the boundary Br between the edges 11a and 12a, the second laser light is irradiated to the surface Wa so as to straddle the gap.

[0084] According to such a configuration and method, for example, a thermal conduction type molten region is generated at the edges 11a, 12a on both sides of the gap by irradiation with the second laser light, which has a relatively high absorption rate in metal materials, so that the gap can be filled more reliably by the weld 14, and thus a weld 14 with higher joining strength can be easily obtained.

[0085] In this embodiment, for example, on the surface Wa, at least a part of the beam B2 (second spot) of the second laser light is located further forward in the sweep direction SD than the beam B1 (first spot) of the first laser light.

[0086] In this embodiment, for example, the beam B1 and the beam B2 at least partially overlap on the surface Wa.

[0087] Also, in this embodiment, for example, on the surface Wa, the beam B2 is wider than the beam B1.

[0088] In addition, in this 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.

[0089] As described above, the inventors have confirmed that welding defects can be reduced in welding by irradiation of the laser light L that forms such beams B1 and B2 on the surface Wa. This is presumably because, as described above, the workpiece W is preheated by the region B2f of the beam B2 before the arrival of the beam B1, and the molten pool of the workpiece W formed by the beam B2 and the beam B1 is more stabilized. Therefore, with the laser light L having such beams B1 and B2, for example, welding with fewer welding defects and higher welding quality can be performed. In addition, with such settings of the beams B1 and B2, for example, the power of the first laser light can be lowered. In addition, when the beams B1 and B2 are irradiated coaxially, there is also an advantage that the relative rotation between the optical head 120 and the workpiece W is not required.

[0090] In the present embodiment, for example, the aspect ratio of the weld metal 14a is preferably 1 or more and 5 or less, and more preferably 1.5 or more and 5 or less.

[0091] With such a configuration, for example, a required weld strength can be easily obtained and the weld width can be prevented from becoming too large.

[0092] In this embodiment, for example, the workpiece is made of any one of a copper-based metal material, an aluminum-based metal material, a nickel-based metal material, an iron-based metal material, and a titanium-based metal material.

[0093] The effect of the welding method of the present embodiment can be obtained when the workpiece is made of any of the above-mentioned materials. Note that the metallic material may or may not be conductive.

[0094] [Modification of holding mechanism] FIG. 8 is a side view showing another example of the holding mechanism 150A. The holding mechanism 150A can be equipped in place of the holding mechanism 150 of the first embodiment. The holding mechanism 150A has a pressing member 151A, a base 154, and a support member 155. The two pressing members 151A are arranged to sandwich the stack 10 in the Y direction. The two support members 155 each support the pressing member 151A so as to be rotatable around a rotation axis Ax along the Y direction. The two support members 155 are arranged on both sides of the stack 10 in the Y direction, and are each attached on the base 154 so that their positions in the Y direction can be changed. The two support members 155 are fixed to the base 154 so that a force is applied from the two pressing members 151 to the stack 10 from both sides in the Y direction to make the first member 11 and the second member 12 approach each other in the Y direction. That is, by adjusting the position of the support member 155 in the holding mechanism 150A, the stack 10 can be set in an appropriate position and posture with respect to the laser light L. In addition, by rotating the pressing member 151A and the stack 10 relative to the support member 155 about the rotation axis Ax, the laser light L can be swept over the surface Wa of the end portion 10a.

[0095] [Second embodiment] 9 is a schematic diagram of a laser welding apparatus 100A according to the second embodiment. In this embodiment, an optical head 120 has a DOE 125 between a collimator lens 121-1 and a mirror 123. Except for this, the laser welding apparatus 100A has a similar configuration to the laser welding apparatus 100 according to the first embodiment.

[0096] The DOE 125 shapes the shape of the beam B1 of the first laser light (hereinafter referred to as the beam shape). As conceptually illustrated in Fig. 10, the DOE 125 has a configuration in which, for example, a plurality of diffraction gratings 125a with different periods are superimposed. The DOE 125 can shape the beam shape by bending the parallel light in a direction influenced by each diffraction grating 125a or by superimposing the diffraction gratings 125a. The DOE 125 can also be referred to as a beam shaper.

[0097] The optical head 120 may have a beam shaper provided after the collimator lens 121-2 for adjusting the beam shape of the second laser light, and a beam shaper provided after the filter 124 for adjusting the beam shapes of the first laser light and the second laser light. By appropriately adjusting the beam shape of the laser light L with the beam shaper, the occurrence of welding defects can be further suppressed.

[0098] 9, a beam having the same beam shape as that of the second laser light can be generated by the DOE 125, which makes it possible to omit the laser device 112. In this case as well, it is possible to suppress the occurrence of spatter during welding.

[0099] [Third embodiment] 11 is a schematic diagram of a laser welding apparatus 100B according to the third embodiment. In this embodiment, the optical head 120 has a galvano scanner 126 between a filter 124 and a condenser lens 122. Except for this point, the laser welding apparatus 100B has the same configuration as the laser welding apparatus 100 according to the first embodiment.

[0100] The galvano scanner 126 has two mirrors 126a and 126b, and is a device that can move the irradiation position of the laser light L and sweep the laser light L without moving the optical head 120 by controlling the angles of the two mirrors 126a and 126b. The angles of the mirrors 126a and 126b are changed by, for example, a motor (not shown). With such a configuration, a mechanism for relatively moving the optical head 120 and the workpiece is not required, and an advantage is obtained in that, for example, the device configuration can be made smaller.

[0101] [Fourth embodiment] 12 is a schematic diagram of a laser welding apparatus 100C of the fourth embodiment. In this embodiment, the optical head 120 has a DOE 125 (beam shaper) between the collimator lens 121-2 and the filter 124. Except for this, the laser welding apparatus 100C has a similar configuration to the laser welding apparatus 100B of the third embodiment. With this configuration, it is possible to obtain the same effect as the third embodiment by having the galvano scanner 126, and the same effect as the second embodiment by having the DOE 125 (beam shaper).

[0102] In this embodiment, the optical head 120 may also have a beam shaper provided after the collimator lens 121-1 to adjust the beam shape of the first laser light, or a beam shaper provided after the filter 124 to adjust the beam shapes of the first laser light and the second laser light.

[0103] [Fifth embodiment] 13 is a schematic diagram of a laser welding apparatus 100D according to a fifth embodiment. In this embodiment, the optical head 120 includes a first portion 120-1 for irradiating the first laser beam L1 and a second portion 120-2 for irradiating the second laser beam L2, each of which is formed by a separate body (housing). With this configuration, the same actions and effects as those of the above-mentioned embodiment can be obtained.

[0104] 14 and 15 show examples of beams B1 and B2 of laser light formed on the surface Wa by the laser welding apparatus 100D. As shown in FIGS. 14 and 15, the laser welding apparatus 100D can arbitrarily set the relative positions of the beams B1 and B2 by setting the relative positions and postures of the first portion 120-1 and the second portion 120-2. Research by the inventors has revealed that, when at least a part of the beam B2 (second spot) is located forward of the beam B1 (first spot) in the sweep direction SD on the surface Wa as shown in FIGS. 14 and 15, and when the beams B1 and B2 are in contact with each other or at least partially overlap each other, the same effect as that of the first embodiment due to the preheating effect of the beam B2 can be obtained. It has also been found that when at least a part of the beam B2 is located forward of the beam B1 in the sweep direction SD, the beams B1 and B2 may be spaced apart by a small distance. 14 and 15 are merely examples, and the arrangement of the beams B1 and B2 obtained by the laser welding apparatus 100D and the size of each of the beams B1 and B2 are not limited to the examples of FIGS.

[0105] [Sixth embodiment] FIG. 16 is a perspective view of a vapor chamber 10E of the sixth embodiment, and FIG. 17 is a cross-sectional view taken along line XVII-XVII of FIG. 16. As shown in FIG. 16, the vapor chamber 10E includes a flat rectangular plate-like first member 11 and a second member 12. The first member 11 and the second member 12 are made of a metal material having a relatively high thermal conductivity. The first member 11 and the second member 12 are overlapped in the Y direction. In the vapor chamber 10E, the edges 11a and 12a of the end portion 10a as the peripheral portion of the first member 11 and the second member 12 overlapping in the Y direction are welded all around by a weld portion 14. The vapor chamber 10E is an example of a product.

[0106] 17, a storage chamber 10b for a fluid medium F is provided between the first member 11 and the second member 12. The storage chamber 10b is formed, for example, by providing a bottomed recess in the second member 12 that opens toward the first member 11. The recess may also be referred to as an opening. The storage chamber 10b is an example of a space.

[0107] The vapor chamber 10E is provided across the high temperature section and the low temperature section. The high temperature section is a heat generating body such as a CPU (central processing unit), and the low temperature section is a heat dissipating body such as a heat sink. The fluid medium F changes from liquid to gas phase by receiving heat from the high temperature section, and changes from gas to liquid phase by dissipating heat to the low temperature section. The fluid medium F that has become gas in a region adjacent to the high temperature section in the accommodation chamber 10b moves in the gaseous state within the accommodation chamber 10b to a region adjacent to the low temperature section within the accommodation chamber 10b. The fluid medium F that has become liquid in a region adjacent to the low temperature section within the accommodation chamber 10b moves within the accommodation chamber 10b to a region adjacent to the high temperature section within the accommodation chamber 10b by capillary action. By transporting heat by the fluid medium F in this way, the vapor chamber 10E can function as a cooling mechanism for the high temperature section.

[0108] As shown in Fig. 17, the end edge 11a and the end edge 12a are joined by a welded portion 14. The welded portion 14 can be formed by the welding method and the laser welding apparatuses 100, 100A to 100D shown in the above-mentioned embodiment and modified examples. The welded portion 14 has a similar configuration to the welded portion 14 of the above-mentioned first embodiment. The end portions 10a as the peripheral portions of the first member 11 and the second member 12 are fully welded by the welded portion 14, thereby sealing the fluid medium F in the storage chamber 10b.

[0109] According to the present embodiment, the same effects as those of the above-mentioned embodiment can be obtained. That is, according to the vapor chamber 10E of the present embodiment, for example, it is easy to obtain a weld 14 having a relatively large weld depth relative to the weld width and thus a higher weld strength, or a weld 14 having fewer weld defects and higher quality.

[0110] [Modification of the sixth embodiment] 18 to 22 show vapor chambers 10F to 10I of modified examples of the sixth embodiment. In a vapor chamber 10F of a first modified example shown in FIG. 18, an edge 11a of a flange 11b of a first member 11 and an edge 12a of a second member 12 are welded by a weld 14. In this vapor chamber 10F, the end portions 10a as peripheral portions of the first member 11 and the second member 12 are also welded all around by the weld 14, thereby sealing the fluid medium F in the storage chamber 10b. In this modified example, a recess forming the storage chamber 10b is provided only in the first member 11.

[0111] 19, an edge 11a as the outer circumferential surface of a first member 11 and an edge 12a of a second member 12 are welded together by a weld 14. In this vapor chamber 10G, the fluid medium F is sealed in the storage chamber 10b by the end portions 10a as the peripheries of the first member 11 and the second member 12 being welded all around by the weld 14. In this vapor chamber 10G, too, the fluid medium F is sealed in the storage chamber 10b. In this modification, too, the recess that forms the storage chamber 10b is provided only in the first member 11.

[0112] 20, an edge 11a as the outer circumferential surface of a first member 11 and an edge 12a as the outer circumferential surface of a second member 12 are welded by a weld 14. In this vapor chamber 10H, the fluid medium F is sealed in the storage chamber 10b by the end portions 10a as the peripheries of the first member 11 and the second member 12 being welded all around by the weld 14. In this vapor chamber 10H, the fluid medium F is sealed in the storage chamber 10b. In this modification, recesses forming the storage chamber 10b are provided in both the first member 11 and the second member 12.

[0113] FIG. 21 is an exploded perspective view of a vapor chamber 10I of a fourth modified example, and FIG. 22 is a cross-sectional view along the Y direction passing through the approximate center of the vapor chamber 10I. In this modified example, a third member 13 is interposed between the first member 11 and the second member 12. The third member 13 is a flat, rectangular, plate-like member made of a metal material with relatively high thermal conductivity. The third member 13 overlaps the first member 11 and the second member 12 in the Y direction. The third member 13 is provided with a plurality of slits 13b as through holes penetrating in the Y direction (stacking direction). Both sides of each slit 13b in the Y direction are blocked by the first member 11 and the second member 12, thereby forming a storage chamber 10b for the fluid medium F in the vapor chamber 10I. The through holes are an example of an opening. Instead of the slits 13b, a recess that does not open the third member 13 may be provided, and the number of slits 13b (through holes) may be one.

[0114] In the vapor chamber 10I, at the end 10a as the periphery of the first member 11 and the third member 13 overlapping in the Y direction, the edges 11a, 13a are welded all around by the weld 14. In addition, at the end 10a as the periphery of the second member 12 and the third member 13 overlapping in the Y direction, the edges 12a, 13a are welded all around by the weld 14. The third member 13 is one of the multiple members. In the vapor chamber 10I of this modification, the fluid medium F is sealed in the storage chamber 10b by the weld 14. The above first to fourth modifications also provide the same effects as the sixth embodiment.

[0115] [Seventh embodiment] 23 is a schematic diagram of a laser welding apparatus 100J according to the fifth embodiment. The laser welding apparatus 100J according to the present embodiment is modified based on the laser welding apparatus 100A according to the second embodiment. The laser welding apparatus 100J includes a control unit 161, a camera 162, a driving mechanism 163, a mirror 164, and a filter 165 in addition to the components of the laser welding apparatus 100A.

[0116] The filter 165 is provided between the mirror 123 and the filter 124. The filter 165 transmits the first laser light from the mirror 123 toward the filter 124 and reflects light (e.g., visible light) from the surface Wa toward the mirror 164. The light reflected by the mirror 164 is input to the camera 162. With this configuration, the camera 162 can capture an image on the surface Wa. The image captured by the camera 162 includes, for example, an image of the boundary between the edges 11a and 12a and an image of the beam (spot) of the laser light L. That is, the image shows the deviation of the spot of the laser light L formed on the surface Wa from the position (predetermined position) of the boundary where the laser light L should be irradiated. Therefore, the image captured by the camera 162 can be said to be a detection result of the deviation of the spot formed on the surface Wa from the predetermined position, and the camera 162 can be said to be an example of a detection mechanism that detects the deviation. In addition, when the position of the spot in the angle of view of the captured image is fixed, it is not necessary for the image of the spot to be included in the captured image, and the control unit 161 can detect the deviation of the spot formed on the surface Wa from a predetermined position from the position of the image of the boundary between the edges 11a and 12a in the captured image.

[0117] The control unit 161 detects the deviation of the spot from the predetermined position from the image captured by the camera 162, and controls the driving mechanism 163 to correct the deviation. The driving mechanism 163 is an actuator that operates in response to a command (electrical signal) from the control unit 161, and can move the optical head 120 in a direction intersecting the Z direction, for example, the Y direction. The driving mechanism 163 can have, 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 a linear motion. At this time, the control unit 161 may perform feedback control that performs control until the deviation is within a predetermined threshold value. The control unit 161 and the driving mechanism 163 are an example of a correction mechanism. With such a configuration, it is possible to reduce the positional deviation of the welded portion 14 from the predetermined position, and therefore it is possible to obtain an advantage that the welding strength of the welded portion 14 can be further increased.

[0118] When applied to the laser welding apparatuses 100B, 100C having the galvano scanner 126 as in the third and fourth embodiments, the control unit 161 may change the irradiation direction of the laser light L, and thus the position of the spot on the surface Wa, instead of changing the position of the optical head 120 by the driving mechanism 163. With such a configuration, the same action and effect can be obtained. In this case, the control unit 161 and the galvano scanner 126 are an example of a correction mechanism.

[0119] Although the embodiment of the present invention has been illustrated above, the above embodiment is merely an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the gist of the invention. In addition, the specifications of each configuration, shape, and the like (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be appropriately changed and implemented.

[0120] For example, a vapor chamber is an example of a product, and the product is not limited to a vapor chamber.

[0121] Furthermore, when the laser beam is swept over the workpiece, the sweep may be performed by known wobbling, weaving, output modulation, or the like, to adjust the surface area of ​​the molten pool.

[0122] The object to be processed may also be a metal plate having a thin layer of another metal on its surface, such as a plated metal sheet. [Explanation of symbols]

[0123] 10...Laminate (product) 10E~10I…Vapor chamber (product) 10a...end 10a1…edge 10b…Containment room (space) 11...First member 11a...Edge 11b...Flange 12...Second member 12a...Edge 13...Third member 13a...Edge 13b…Slit 14…Welded section 14a…Weld metal 14a1…first part 14a2…Second part 14b…Heat affected zone 100, 100A-100D, 100J...Laser welding equipment (welding equipment) 111...Laser device (first laser oscillator) 112...Laser device (second laser oscillator) 120...Optical head 120-1…First part 120-2…Second part 121, 121-1, 121-2...Collimating lenses 122...Condenser lens 123…Mirror 124…Filter 125...DOE (diffractive optical element) 125a...Diffraction grating 126...Galvano scanner (correction mechanism) 126a, 126b…Mirror 130...Optical fiber 150,150A…holding mechanism 151, 151A...Pressing member 152, 153...Support member 154…Bass 155...Support member 161...Control unit (correction mechanism) 162...Camera (detection mechanism) 163...Drive mechanism (correction mechanism) 164…Mirror 165…Filter A...Crystal grain Ax...Rotation axis B1…Beam (first spot) B1a…Outer edge B2…Beam (second spot) B2a…Outer edge B2b…area B2f…area Br...boundary C...center point D1…Spot diameter (outer diameter) D2: Spot diameter (outer diameter) d…Depth dm: depth (of weld metal) F...Fluid medium I…area L: Laser light L1…First laser beam L2: Second laser beam SD…Sweep direction W…Processing target Wa…Surface wb…Width (at the surface of the weld metal) wm: width (of the first and second regions) X…direction (second direction) Y...direction (first direction, stacking direction) Z…direction (third direction) Z1...first area (first part) Z2…Second area (second part)

Claims

1. A welding method for welding adjacent edges in a first direction, the method comprising: irradiating a laser beam from an outside of an end portion of a plurality of members overlapping in a first direction, the end portions extending in a second direction intersecting the first direction, with the laser beam being swept in the second direction to form a weld extending in the second direction, the method comprising: 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, on a surface of the end portion extending in the first direction and the second direction, an entire area of ​​a first spot formed by the first laser light overlaps with a second spot formed by the second laser light, and a second outer edge of the second spot surrounds the first outer edge of the first spot at a distance; The welded portion is a weld metal extending in a third direction intersecting the first direction and the second direction from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction; a heat-affected zone located around the weld metal; having the weld metal has a second portion in contact with the surface, which is formed by being cooled after being melted by heat conduction type due to the irradiation of the second laser light, and a first portion in contact with the surface, which is formed by being cooled after being melted by keyhole type due to the irradiation of the first laser light, which is located on the opposite side of the surface with respect to the second portion, extends in the third direction from a position in contact with the second portion, and is not exposed on the surface side, The welding method according to claim 1, wherein an aspect ratio of the depth of the weld metal in the third direction to the width of the weld metal in the first direction is 1.5 or more and 5 or less.

2. 2. The welding method according to claim 1, wherein the second laser light has a wavelength of 400 nm or more and 500 nm or less.

3. The welding method according to claim 1 or 2, wherein the second laser light is irradiated so as to span a gap in a boundary between the edges adjacent in the first direction in the first direction.

4. The welding method according to any one of claims 1 to 3, wherein each of the plurality of members is made of any one of a copper-based metal material, an aluminum-based metal material, a nickel-based metal material, an iron-based metal material, and a titanium-based metal material.

5. A laser device that outputs laser light; an optical head that irradiates the laser light outputted from the laser device; Equipped with A welding device which welds adjacent edges in a first direction to each other by irradiating laser light from an outside of an end portion of a plurality of members overlapping in a first direction, the end portions extending in a second direction intersecting the first direction, along a third direction intersecting the first direction and the second direction, while sweeping the laser light in the second direction to form a weld extending in the second direction, the welding device comprising: 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, on a surface of the end portion extending in the first direction and the second direction, an entire area of ​​a first spot formed by the first laser light overlaps with a second spot formed by the second laser light, and a second outer edge of the second spot surrounds the first outer edge of the first spot at a distance; The welded portion is a weld metal extending in a third direction intersecting the first direction and the second direction from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction; a heat-affected zone located around the weld metal; having the weld metal has a second portion in contact with the surface, which is formed by being cooled after being melted by heat conduction type due to the irradiation of the second laser light, and a first portion in contact with the surface, which is formed by being cooled after being melted by keyhole type due to the irradiation of the first laser light, which is located on the opposite side of the surface with respect to the second portion, extends in the third direction from a position in contact with the second portion, and is not exposed on the surface side, The aspect ratio of the weld metal's depth in the third direction to its width in the first direction is 1.5 or more and 5 or less.

6. 6. The welding apparatus of claim 5, further comprising a beam shaper for splitting the laser light into a plurality of beams.

7. The welding apparatus according to claim 5 or 6, further comprising a galvanometer scanner that changes the emission direction of the laser light so that the laser light moves in a sweeping direction along the second direction on a surface of the end portion extending in the first direction and the second direction.

8. The welding device according to any one of claims 5 to 7, further comprising a rotation mechanism that rotates the end portion about a rotation axis along the first direction.

9. a detection mechanism for detecting a deviation of a spot formed on the surface by the laser light from a predetermined position; A correction mechanism for correcting the deviation; The welding device according to any one of claims 5 to 8, comprising:

Images