JP2022060808A - Laser welding method and laser welding device - Google Patents

Abstract

To provide a laser welding method for spot welding workpiece having a gap.SOLUTION: Workpiece 200 is spot welded by irradiating the surface of the workpiece 200 with a laser beam LB by two-dimensional scanning while traveling the laser beam LB along a spot patter SP. At this time, the workpiece 200 is scanned with the laser beam LB so as to draw a scanning pattern SP1 on the surface of the workpiece 200 and pass an original point O1 of the scanning pattern SP1 on the spot pattern SP1. The spot pattern SP is an annular pattern or a linear pattern in which one end and the other end are positioned with an equal distance from a predetermined center point. The scanning pattern SP1 has the same width or different widths on both sides of the spot pattern SP across a tangent line of the spot pattern SP at the original point O1.SELECTED DRAWING: Figure 5

Description

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

In laser welding, since the power density of the laser beam applied to the work to be welded is high, high-speed and high-quality welding can be performed. In particular, in scanning welding in which welding is performed while scanning the laser beam on the surface of the work at high speed, the laser beam can be moved to the next welding point at high speed during the non-welding period, thus shortening the total welding time. (See, for example, Patent Document 1). Further, as for the method of scanning the laser beam, a method of scanning the laser beam so as to draw a resage pattern on the surface of the work has been conventionally proposed (see, for example, Patent Documents 2 and 3).

Japanese Unexamined Patent Publication No. 2005-095934 Japanese Unexamined Patent Publication No. 60-177983 Japanese Unexamined Patent Publication No. 11-104877

However, in the conventional scanning technology as proposed in Patent Documents 1 to 3, the main point is to perform high-speed welding by moving the laser beam, and it can play a major role in improving production. However, no particular attention has been paid to suppressing the occurrence of welding defects due to the gap between the workpieces to be welded.

The present disclosure has been made in view of such a point, and an object thereof is to provide a laser welding method and a laser welding apparatus capable of spot welding a work even if there is a gap between the works to be welded.

In order to achieve the above object, the laser welding method according to the present disclosure is to scan the laser beam two-dimensionally while advancing the laser beam along a spot pattern and irradiate the surface of the workpiece with the work. The laser beam is scanned so that a predetermined pattern is drawn on the surface of the work and the origin of the predetermined pattern passes over the spot pattern. The spot pattern is an annular pattern or a linear pattern in which one end and the other end are equidistant from a predetermined center point, and the predetermined pattern is a tangent line of the spot pattern at the origin. The spot pattern is characterized by having the same width or different widths on both sides of the spot pattern.

The laser welding apparatus according to the present disclosure includes at least a laser oscillator that generates a laser beam, a laser head that receives the laser beam and irradiates the work, and at least a controller that controls the operation of the laser head. The laser head has a laser beam scanner that scans the laser beam in each of a first direction and a second direction intersecting the first direction, and the controller causes the laser beam to travel along a spot pattern. While driving and controlling the laser beam scanner so as to scan the laser beam two-dimensionally, the controller further controls the laser beam so that the laser beam draws a predetermined pattern on the surface of the work. The laser light scanner is driven and controlled so that the origin of the pattern passes over the spot pattern, and the spot pattern is an annular pattern, or one end and the other end are equidistant from a predetermined center point. It is a linear pattern, and the predetermined pattern is characterized in that the width is the same or different on both sides of the spot pattern with the tangent line of the spot pattern at the origin thereof interposed therebetween.

According to the present disclosure, a workpiece having a gap can be spot welded. In addition, the shape of the formed weld bead can be improved.

It is a schematic block diagram of the laser welding apparatus which concerns on Embodiment 1. FIG. It is a schematic block diagram of a laser light scanner. It is sectional drawing of the work. It is a figure which shows the scanning pattern of a laser beam. It is a figure which shows the scanning locus of a laser beam along a welding direction. It is a schematic diagram when the scanning pattern shown in FIG. 4 is arranged on the spot pattern. It is a schematic diagram which shows the state change of the welded part of the work when there is no scanning of a laser beam for comparison. It is a schematic diagram which shows the state change of the welded part of the work at the time of laser light irradiation which concerns on Embodiment 1. FIG. It is a figure which shows the 1st spot pattern which concerns on modification 1. FIG. It is a figure which shows the 2nd spot pattern. It is a figure which shows the 3rd spot pattern. It is a figure which shows the 4th spot pattern. It is a figure which shows the 5th spot pattern. It is a figure which shows the sixth spot pattern. It is a figure which shows the 7th spot pattern. It is a figure which shows the scanning pattern of the laser beam which concerns on the modification 2. It is a figure which shows the scanning locus of a laser beam along a welding direction. It is a figure which shows another scanning pattern of the laser beam which concerns on modification 2. It is a figure which shows another scanning locus of a laser beam along a welding direction. It is a figure which shows the 1st scanning pattern of the laser beam which concerns on the modification 3. It is a figure which shows the 2nd scanning pattern of a laser beam. It is a figure which shows the 3rd scanning pattern of a laser beam.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely an example and is not intended to limit the present disclosure, its application or its use.

(Embodiment 1)
[Construction of laser welding equipment and laser light scanner]
FIG. 1 shows a schematic diagram of the configuration of the laser welding apparatus according to the present embodiment, and FIG. 2 shows a schematic configuration diagram of a laser light scanner. FIG. 3 shows a schematic cross-sectional view of the work.

In the following description, the direction parallel to the traveling direction of the laser beam LB from the reflection mirror 33 toward the laser beam scanner 40 is the X direction, and the direction parallel to the optical axis of the laser beam LB emitted from the laser head 30. The Z direction and the directions orthogonal to the X direction and the Z direction may be referred to as the Y direction, respectively. When the surface of the work 200 is a flat surface, the XY plane including the X direction and the Y direction in the plane may be substantially parallel to the surface or may form a constant angle with the surface.

As shown in FIG. 1, the laser welding apparatus 100 includes a laser oscillator 10, an optical fiber 20, a laser head 30, a controller 50, and a manipulator 60.

The laser oscillator 10 is a laser light source that is supplied with electric power from a power source (not shown) to generate a laser beam LB. The laser oscillator 10 may be composed of a single laser light source or a plurality of laser modules. In the latter case, the laser light emitted from each of the plurality of laser modules is combined and emitted as the laser light LB. Further, the laser light source or the laser module used in the laser oscillator 10 is appropriately selected according to the material of the work 200, the shape of the welded portion, and the like.

For example, a fiber laser, a disk laser, or a YAG (Yttrium Aluminum Garnet) laser can be used as a laser light source. In this case, the wavelength of the laser beam LB is set in the range of 1000 nm to 1100 nm. Further, the semiconductor laser may be used as a laser light source or a laser module. In this case, the wavelength of the laser beam LB is set in the range of 800 nm to 1000 nm. Further, the visible light laser may be used as a laser light source or a laser module. In this case, the wavelength of the laser beam LB is set in the range of 400 nm to 600 nm.

The optical fiber 20 is optically coupled to the laser oscillator 10, and the laser light LB generated by the laser oscillator 10 is incident on the optical fiber 20 and transmitted inside the optical fiber 20 toward the laser head 30.

The laser head 30 is attached to the end of the optical fiber 20 and irradiates the work 200 with the laser light LB transmitted from the optical fiber 20.

Further, the laser head 30 has a collimation lens 32, a reflection mirror 33, a condenser lens 34, and a laser light scanner 40 as optical components, and these optical components have a predetermined arrangement relationship inside the housing 31. Is kept and housed.

The collimation lens 32 receives the laser beam LB emitted from the optical fiber 20, converts it into parallel light, and causes it to be incident on the reflection mirror 33. Further, the collimation lens 32 is connected to a drive unit (not shown) and is configured to be displaceable in the Z direction in response to a control signal from the controller 50. By displacing the collimation lens 32 in the Z direction, the focal position of the laser beam LB can be changed, and the laser beam LB can be appropriately irradiated according to the shape of the work 200. That is, the collimation lens 32 also functions as a focal position adjusting mechanism for the laser beam LB in combination with a drive unit (not shown). The condenser lens 34 may be displaced by the drive unit to change the focal position of the laser beam LB.

The reflection mirror 33 reflects the laser light LB transmitted through the collimation lens 32 and causes it to be incident on the laser light scanner 40. The surface of the reflection mirror 33 is provided so as to form an optical axis of about 45 degrees with the optical axis of the laser beam LB transmitted through the collimation lens 32.

The condenser lens 34 concentrates the laser light LB reflected by the reflection mirror 33 and scanned by the laser light scanner 40 on the surface of the work 200.

As shown in FIG. 2, the laser light scanner 40 is a known galvano scanner having a first galvano mirror 41 and a second galvano mirror 42. The first galvano mirror 41 has a first mirror 41a, a first rotation shaft 41b, and a first drive unit 41c, and the second galvano mirror 42 has a second mirror 42a, a second rotation shaft 42b, and a second drive unit. It has 42c. The laser beam LB transmitted through the condenser lens 34 is reflected by the first mirror 41a and further reflected by the second mirror 42a to irradiate the surface of the work 200.

For example, the first drive unit 41c and the second drive unit 42c are galvano motors, and the first rotation shaft 41b and the second rotation shaft 42b are output shafts of the motor. Although not shown, the first drive unit 41c is rotationally driven by a driver that operates in response to a control signal from the controller 50, so that the first mirror 41a attached to the first rotation shaft 41b becomes the first rotation shaft. It rotates around the axis of 41b. Similarly, the second drive unit 42c is rotationally driven by a driver that operates in response to a control signal from the controller 50, so that the second mirror 42a attached to the second rotary shaft 42b becomes the axis of the second rotary shaft 42b. Rotate around.

The laser beam LB is scanned in the X direction by the first mirror 41a rotating around the axis of the first rotation shaft 41b to a predetermined angle. Further, the second mirror 42a rotates around the axis of the second rotating shaft 42b to a predetermined angle, so that the laser beam LB is scanned in the Y direction. That is, the laser light scanner 40 is configured to scan the laser light LB two-dimensionally in the XY plane and irradiate the work 200.

The controller 50 controls the laser oscillation of the laser oscillator 10. Specifically, laser oscillation control is performed by supplying control signals such as an output current and an on / off time to a power source (not shown) connected to the laser oscillator 10. Further, the controller 50 controls the output of the laser beam LB.

Further, the controller 50 controls the operation of the laser head 30 according to the content of the selected laser welding program. Specifically, the drive control of the laser light scanner 40 provided on the laser head 30 and the drive unit (not shown) of the collimation lens 32 is performed. Further, the controller 50 controls the operation of the manipulator 60. The laser welding program is stored in a storage unit (not shown) provided inside the controller 50 or at another location, and is called by the controller 50 by a command from the controller 50.

The controller 50 has an integrated circuit such as an LSI or a microcomputer (not shown), and the function of the controller 50 described above is realized by executing a laser welding program which is software on the integrated circuit. A controller 50 that controls the operation of the laser head 30 and a controller 50 that controls the output of the laser beam LB may be provided separately.

The manipulator 60 is an articulated robot and is attached to the housing 31 of the laser head 30. Further, the manipulator 60 is connected to the controller 50 so as to be able to send and receive signals, and moves the laser head 30 so as to draw a predetermined trajectory according to the above-mentioned laser welding program. In addition, another controller (not shown) that controls the operation of the manipulator 60 may be provided.

The laser welding device 100 shown in FIG. 1 can perform laser welding on workpieces 200 having various shapes. For example, as shown in FIG. 3, the work 200 in which the first plate material 210 and the second plate material 220 made of steel plates are overlapped is irradiated with laser light LB, and lap welding is performed. As shown in FIG. 3, a predetermined gap g1 is provided between the first plate material 210 and the second plate material 220. However, the gap g1 may be zero, that is, the first plate material 210 and the second plate material 220 may be closely overlapped with each other without a gap. Needless to say, the structure and material of the work 200 to be laser welded are not limited to the example shown in FIG. For example, a zinc plating layer (not shown) may be formed on the surfaces of the first plate material 210 and the second plate material 220 shown in FIG. Further, it may be a steel material such as stainless steel, a non-iron alloy material such as an aluminum alloy or a copper alloy, or the like.

[Mathematical expression of laser beam scanning pattern]
FIG. 4 shows a scanning pattern of the laser beam, and the laser beam LB is scanned so as to draw the scanning pattern SP1 in the XY plane, in this case, on the surface of the work 200. In order to make the following explanation easier to understand, the X direction and the Y direction of the scanning pattern SP1 are referred to as an X1 axis and a Y1 axis, respectively.

The width of the scanning pattern SP1 shown in FIG. 4 in the X1 direction is substantially equal to the width in the Y1 direction. In the specification of the present application, "substantially equal" or "substantially the same" means that the control results of the controlled objects are the same or the same including the error of the control system, and both of them are strictly the same or the same. It does not require that they be the same. Further, "substantially equal" or "substantially the same" is also used to mean the same or the same including manufacturing tolerances and assembly tolerances of each part and the like.

The scanning pattern SP1 shown in FIG. 4 is a Lissajous pattern obtained by vibrating the laser beam LB in the X1 direction in a sine and cosine shape with a predetermined frequency and in the Y1 direction in a sine and cosine shape with a frequency different from the X1 direction (hereinafter,). It is also called a Lissajous figure). The origin O1 of the scanning pattern SP1 corresponds to the center point of the resage pattern. Further, as described above, the scanning pattern of the laser beam LB in the X1 direction and the Y1 direction is determined based on the rotational motion of the first mirror 41a and the second mirror 42a. Generally, the position coordinates of the scanning pattern SP1 shown in FIG. 4 obtained by driving the first mirror 41a are X11, and the position coordinates of the scanning pattern SP1 shown in FIG. 4 obtained by driving the second mirror 42a are Y11. Then, the position coordinates X11 and Y11 are expressed by the following equations (1) and (2), respectively.

X11 = a × sin (nt) ・ ・ ・ (1)
Y11 = b × sin (mt + φ) ・ ・ ・ (2)

here,
a: Amplitude of the scanning pattern SP1 shown in FIG. 4 in the X1 direction b: Amplitude of the scanning pattern SP1 shown in FIG. 4 in the Y1 direction n: Frequency of the first mirror 41a m: Frequency of the second mirror 42a t: Time φ: No. It is a phase difference when the 1 mirror 41a or the 2nd mirror 42a is driven, and specifically, is an angular deviation amount provided during the rotational movement of the 1st mirror 41a and the 2nd mirror 42a.

The position coordinates X11 and Y11 shown in the equations (1) and (2) are represented by the static coordinate system of the scanning pattern SP1 in a state where the position of the laser head 30 is fixed.

Further, the frequency n and the frequency m correspond to the drive frequencies of the first mirror 41a and the second mirror 42a, respectively.

The scanning pattern SP1 shown in FIG. 4 has a figure eight shape corresponding to the case where a = 1, b = 1, n = 2, m = 1, φ = 0 in the equations (1) and (2). It is a lithage pattern. a and b are normalized by 1. The phase difference φ in the equations (1) and (2) may be either 0 degree or 180 degrees.

[Laser welding method]
FIG. 5 shows a scanning locus of the laser beam along the welding direction, and in the present embodiment, consider a case where the manipulator 60 scans the laser beam LB along the spot pattern SP shown by the alternate long and short dash line in FIGS. 5 and 6. ..

The spot pattern SP of the present embodiment is a circular pattern having a center point O and having a predetermined radius. In the present embodiment, the surface of the work 200 is irradiated with the laser beam LB while the laser beam LB is moved at a predetermined linear velocity along the spot pattern SP. Further, the laser light scanner 40 is used to two-dimensionally scan the laser light LB so as to draw the scanning pattern SP1 shown in FIG. 5 around the spot pattern SP on the surface of the work 200. In this embodiment, the case where the work 200 shown in FIG. 3 is spot welded will be described as an example.

The scanning pattern SP1 shown in FIG. 4 is obtained by scanning the laser beam LB from the origin O1 in the direction of the arrow AR1 shown in FIG. 4 during one cycle. The laser beam LB may be scanned from the origin O1 in the direction of the arrow AR2 shown in FIG. 4 during one cycle.

As shown in FIG. 5, the scanning pattern SP1 has the same width on both sides of the spot pattern SP with the tangent line of the spot pattern SP at the origin O1 interposed therebetween. As shown in FIG. 5, the actual waveform of the scanning pattern SP1 changes according to the traveling speed of the laser beam LB. For example, although not shown, in the scanning pattern SP1, the portion located outside the spot pattern SP in the radial direction from the origin O1 and the portion located inside in the radial direction are the welding direction WD, in this case, along the spot pattern SP. It is separated along the clockwise direction, and the separation distance changes according to the traveling speed of the laser beam LB. Further, in the scanning pattern SP1, both the portion located on the outer side in the radial direction and the portion located on the inner side in the radial direction from the origin O1 have a deformed shape extending along the circumferential direction of the spot pattern SP.

The scanning method of the laser beam LB for realizing the pattern of FIG. 5 will be described in a little more detail with reference to FIG. FIG. 6 shows a schematic diagram when the scanning pattern shown in FIG. 4 is placed at each position on the spot pattern SP.

As described above, the irradiation width of the laser beam LB is the same on the inner side and the outer side in the radial direction of the spot pattern SP across the tangent line of the spot pattern SP, but the origin O1 of the scanning pattern SP1 is always spotted. It is characterized in that its X1 axis coincides with the tangential direction of the spot pattern SP while being positioned at the pattern SP. That is, in order to realize the pattern of FIG. 5 on the XY plane, in other words, when drawing the scanning pattern SP1, the X1 axis of the scanning pattern SP1 is actually set in the welding direction WD, which is the traveling direction of the laser beam LB. Along the welding direction WD (X1 direction), as shown in the equation (1), the laser beam LB is vibrated in a sinusoidal shape having a first frequency. At the same time, as shown in the equation (2), the laser beam has a second frequency along the direction intersecting the welding direction WD (Y1 direction), in this case, along the direction intersecting the spot pattern SP. Vibrate the LB. By doing so, as shown in FIG. 5, the scanning pattern SP1 can be continuously drawn along the spot pattern SP on the surface of the work 200. In other words, in FIG. 5, the X1 axis direction and the Y1 axis direction during drawing always change, and the X axis direction always coincides with the tangential direction on the spot pattern SP.

Although not shown in the above description, scanning patterns SP1 having different widths may be formed on both sides of the spot pattern SP. For example, it is desirable to increase the size of the portion of the scanning pattern SP1 that is irradiated to the outside of the spot pattern SP rather than the portion that is irradiated to the inside of the spot pattern SP. By doing so, the first interval L1 and the second interval L2 (see FIG. 5) between the adjacent scanning patterns SP1 formed in the tangential direction of the spot pattern SP become substantially equal, and the melting formed by the scanning pattern SP1 becomes substantially equal. The amount of heat input to each part of the pond becomes uniform, and the bead shape becomes smooth.
[Effects, etc.]
As described above, in the laser welding method according to the present embodiment, the laser beam LB is two-dimensionally scanned while advancing along the spot pattern SP, and the surface of the work 200 is irradiated with the laser beam LB. The work 200 is provided with a welding step for welding the work 200. The spot pattern SP of the present embodiment is a circular pattern having a center point O and having a predetermined radius.

In the welding step, the laser beam LB draws the scanning pattern SP1 on the surface of the work 200, the origin O1 of the scanning pattern SP1 passes over the spot pattern SP, and the axial direction of the scanning pattern SP1 is tangent to the spot pattern SP. The laser beam LB is scanned so as to coincide with the radial direction.

The scanning pattern SP1 is a figure-eight resage pattern, and has the same width on both sides of the spot pattern SP with the tangent line of the spot pattern SP at the origin O1 interposed therebetween. In the welding step, the laser beam LB is vibrated in a sinusoidal shape having a first frequency along the welding direction WD (tangential direction of the spot pattern SP or the X1 direction) which is the traveling direction of the laser beam LB, and is combined with the welding direction WD. It is vibrated in a sinusoidal shape having a second frequency along the intersecting direction (diameter direction of the spot pattern SP or Y1 direction). In this way, the laser beam LB is scanned so as to draw a resage pattern on the surface of the work 200.

According to the present embodiment, even when a gap (= g1) exists between the first plate material 210 and the second plate material 220, the first plate material 210 and the second plate material 220 can be reliably spot-welded. can. In addition, the shape of the formed weld bead can be improved. This will be described further.

FIG. 7 schematically shows a change in the state of the welded portion of the work when there is no scanning of the laser beam for comparison, and FIG. 8 shows a change in the state of the welded portion of the work when the laser beam is irradiated according to the present embodiment. Is schematically shown. In any case, the case where a wide gap g1 exists between the first plate material 210 and the second plate material 220 is schematically shown.

Generally, when the laser beam LB is irradiated without scanning along the circular spot pattern SP as shown in FIGS. 5 and 6, the beam width of the laser beam LB is narrow, so that the laser beam LB is irradiated on the surface of the work 200. The width also becomes narrower. In such a case, as shown in FIG. 7, when the laser beam LB1 is moved at high speed, the molten metal 311 generated from the first plate material 210 sufficiently fills the gap g1 between the first plate material 210 and the second plate material 220. Not formed enough to fill. Therefore, a hole is generated in the welded portion of the work 200. In order to avoid such a problem, for example, it is conceivable to defocus the laser beam LB to widen the irradiation width of the laser beam LB1 on the surface of the work 200. However, in this case, since the power density of the laser beam LB1 decreases on the surface of the work 200, there is a possibility that the penetration depth becomes shallow especially in the lower second plate material 220.

On the other hand, according to the present embodiment, the laser beam LB is scanned inside and outside the spot pattern SP in the radial direction across the spot pattern SP to irradiate the work 200. By doing so, it is possible to widen the irradiation width of the laser beam LB on the surface of the work 200 while ensuring the penetration depth.

For example, as shown in FIG. 8, at the drawing position A of the scanning pattern SP1, the molten metal is formed on the left side of the welded portion on the paper surface by the laser beam LB2 whose optical axis is indicated by aa', but the drawing position C. Then, the molten metal is formed on the right side of the welded portion by the laser beam LB2 whose optical axis is indicated by cc'. Therefore, even when a wide gap (= g1) exists between the first plate material 210 and the second plate material 220, a large molten pool 312 can be formed by the welded portion by drawing the scanning pattern SP1. The 1st plate material 210 and the 2nd plate material 220 can be reliably spot welded. In addition, the shape of the formed weld bead can be improved.

Further, by scanning the laser beam LB so that the origin O1 of the scanning pattern SP1 passes over the spot pattern SP, the irradiation width of the laser beam LB is widened by sandwiching the spot pattern SP, and the radial direction of the spot pattern SP. The irradiation doses on the inside and outside of the can be made evenly close to each other. This increases the size of the keyhole 302 and the molten pool 312 and enhances their stability.

Further, by using the scanning pattern SP1 as a Lissajous pattern, the scanning frequency can be increased, a continuous weld bead with less unevenness can be formed along the spot pattern SP, and the first plate material 210 and the second plate material 220 can be reliably connected. Can be spot welded.

Needless to say, the scanning frequency of the scanning pattern SP1 can change according to its size. For example, when the size of the scanning pattern SP1 in the X direction is 1 mm, the scanning frequency can be set to about 100 to 1000 Hz. Needless to say, if the size of the scanning pattern SP1 becomes large, the scanning frequency is lowered. For example, when the size of the scanning pattern SP1 in the X direction is 5 mm, the scanning frequency can be set to about 50 to 300 Hz. In any case, it is possible to increase the scanning frequency according to the performance of the first mirror 41 and the second mirror 42.

In the scanning pattern SP1, it is preferable that the center line passing through the origin O1 is always orthogonal to the tangent line of the spot pattern SP at the origin O1.

Further, scanning patterns SP1 having different widths may be formed on both sides of the spot pattern SP. For example, in the scanning pattern SP1, the size of the portion irradiated to the outside of the spot pattern SP can be made larger than the size of the portion irradiated to the inside of the spot pattern SP. By doing so, the irradiation amount on the inner side and the outer side in the radial direction of the spot pattern SP can be made closer to each other more evenly. By doing so, as described above, the irradiation width and the irradiation amount of the laser beam LB are the same or different values on the inner side and the outer side in the radial direction of the spot pattern SP with the spot pattern SP interposed therebetween. Can be set to. This makes it possible to improve the shape of the formed weld bead.

Further, in order to draw the scanning pattern SP1 shown in FIG. 4, it is necessary to set the ratio of the first frequency to the second frequency to 1: 2.

The laser welding apparatus 100 according to the present embodiment includes a laser oscillator 10 that generates a laser beam LB, a laser head 30 that receives the laser beam LB and irradiates the work 200, and an operation of the laser head 30 and a laser beam LB. It includes at least a controller 50 that controls the output P.

The laser head 30 has a laser light scanner 40 that scans the laser light LB in each of the X direction (first direction) and the Y direction (second direction) intersecting the X direction.

The controller 50 drives and controls the laser light scanner 40 so as to scan the laser light LB two-dimensionally while advancing the laser light LB along the spot pattern SP.

Further, in the controller 50, the laser beam LB draws the scanning pattern SP1 on the surface of the work 200, and the origin O1 of the scanning pattern SP1 is on the spot pattern SP which is a circular pattern having a center point O and having a predetermined radius. The laser light scanner 40 is driven and controlled so as to pass through.

According to the laser welding apparatus 100 of the present embodiment, the irradiation width of the laser beam LB is widened by sandwiching the spot pattern SP, and the irradiation amounts on the inside and outside of the spot pattern SP in the radial direction are evenly approached or different. Can be set to a value. As a result, even when a gap (= g1) exists between the first plate material 210 and the second plate material 220, the first plate material 210 and the second plate material 220 are surely spot welded while reducing spatter. And the strength of the welded part can be increased. In addition, the shape of the formed weld bead can be improved.

Further, the controller 50 vibrates the laser beam LB in a sine wave shape having a first frequency along the welding direction WD, and also vibrates in a sine wave shape having a second frequency along the direction intersecting the welding direction WD. As a result, the controller 50 drives and controls the laser light scanner 40 so that the scanning pattern SP1 drawn on the surface of the work 200 by the laser light LB becomes a resage pattern.

By doing so, the scanning frequency of the scanning pattern SP1 can be increased, a continuous weld bead with less unevenness can be formed along the spot pattern SP, and the first plate material 210 and the second plate material 220 can be reliably spot welded. can do.

The laser welding device 100 further includes a manipulator 60 to which the laser head 30 is attached, and the controller 50 controls the operation of the manipulator 60. The manipulator 60 moves the laser head 30 in a predetermined direction with respect to the surface of the work 200.

By providing the manipulator 60 in this way, the welding direction of the laser beam LB or the position of the welding point can be changed. Further, laser welding can be easily performed on a work 200 having a complicated shape, for example, a three-dimensional shape.

The laser oscillator 10 and the laser head 30 are connected by an optical fiber 20, and the laser light LB is transmitted from the laser oscillator 10 to the laser head 30 through the optical fiber 20.

By providing the optical fiber 20 in this way, it becomes possible to perform laser welding on the work 200 installed at a position away from the laser oscillator 10. This increases the degree of freedom in arranging each part of the laser welding apparatus 100.

The laser light scanner 40 is composed of a first galvano mirror 41 that scans the laser light LB in the X direction and a second galvano mirror 42 that scans the laser light LB in the Y direction.

By configuring the laser light scanner 40 in this way, the laser light LB can be easily scanned two-dimensionally. Further, since a known galvano scanner is used as the laser light scanner 40, it is possible to suppress an increase in the cost of the laser welding apparatus 100.

The laser head 30 further includes a collimation lens 32, and the collimation lens 32 is configured to change the focal position of the laser beam LB along the Z direction intersecting each of the X direction and the Y direction. In other words, the collimation lens 32 is configured to change the focal position of the laser beam LB along the Z direction intersecting the surface of the work 200. That is, the collimation lens 32 also functions as a focal position adjusting mechanism for the laser beam LB in combination with a drive unit (not shown). That is, the focal position can be changed according to an arbitrary irradiation position during welding, and the degree of freedom in setting welding conditions can be increased.

By doing so, the focal position of the laser beam LB can be easily changed, and the laser beam LB can be appropriately irradiated according to the shape of the work 200.

<Modification 1>
9A to 9G show the first to seventh spot patterns according to the present modification, respectively.

In the first embodiment, the case where the laser beam LB is advanced along the circular spot pattern SP has been described as an example, but the shape of the spot pattern SP is not particularly limited to this when the work 200 is spot welded.

For example, as shown in FIG. 9A, the spot pattern SP may be an open circle shape in which a part is open, or as shown in FIG. 9E, the spot pattern SP may be a waveform. Further, as shown in FIG. 9G, the spot pattern SP may be substantially U-shaped. As shown in FIGS. 9A, 9C to 9E and 9G, when a part of the spot pattern SP was opened, it was generated from air or oil between the first plate material 210 and the second plate material 220. Since there is an outlet for steam and the like, the shape of the weld bead can be improved. Further, the spot pattern SP shown in FIGS. 9A, 9C to 9E and 9G is a linear pattern in which one end and the other end are equidistant from a predetermined center point O.

When the spot pattern SP is an annular pattern or a partially open annular pattern as shown in FIGS. 5 and 6 and 9A to 9C and FIG. 9F, scanning patterns having different widths on both sides of the spot pattern SP are used. SP1 may be formed. For example, it is desirable to increase the size of the portion of the scanning pattern SP1 that is irradiated to the outside of the spot pattern SP rather than the portion that is irradiated to the inside of the spot pattern SP. By doing so, the first interval L1 and the second interval L2 (see FIG. 5) between the adjacent scanning patterns SP1 formed in the tangential direction of the spot pattern SP become substantially equal, and the molten pool formed by the scanning pattern SP1 becomes substantially equal. The amount of heat input to each part of the above becomes uniform, and the bead shape becomes smooth.

<Modification 2>
FIG. 10 shows a scanning pattern of the laser beam according to the present modification, and FIG. 11 shows a scanning locus of the laser beam along the welding direction.

As shown in FIG. 10, the scanning pattern SP2 shown in this modification is different from the scanning pattern SP1 shown in the first embodiment in that it is a circular pattern. The scanning pattern SP2 shown in FIG. 10 is obtained by scanning the laser beam LB from the origin O1 in the direction of the arrow AR1 shown in FIG. 10 during one cycle. The laser beam LB may be scanned from the origin O1 in the direction of the arrow AR2 shown in FIG. 10 during one cycle.

Further, as shown in FIG. 10, the actual waveform of the scanning pattern SP2 changes according to the traveling speed of the laser beam LB, which is the same as described in the first embodiment.

When the laser beam LB is scanned as shown in FIGS. 10 and 11, the same effect as that of the configuration shown in the first embodiment can be obtained. That is, even when a gap (= g1) exists between the first plate material 210 and the second plate material 220, the first plate material 210 and the second plate material 220 can be reliably spot-welded, and the welded portion can be welded. The strength can be increased. In addition, the shape of the formed weld bead can be improved.

Further, since the scanning pattern SP2 is a simple circular pattern, the scanning frequency can be increased as compared with the example shown in the first embodiment. For example, when the diameter of the scanning pattern SP2 is 1 mm, the scanning frequency can be set to about 3 kHz. Further, when the size of the scanning pattern SP1 in the X direction is 5 mm, the scanning frequency can be set to about 500 Hz.

As is clear from FIG. 11, unlike the example shown in the first embodiment, since the drawing length of the laser beam LB is different between the outside and the inside in the radial direction of the spot pattern SP, the amount of heat input to the work 200 is also different. When the work 200 is spot welded, it is possible to finely control the appearance of the beads inside and outside the spot pattern SP, particularly the shape of the portion at the time of the bead, while keeping this point in mind.

Further, as shown in FIGS. 12 and 13, the scanning pattern SP3 can be a sinusoidal pattern. In this case, since the drawing length is shortened at the outer end portion and the inner end portion in the radial direction of the spot pattern SP, when spot welding the work 200, the inner and outer beads of the spot pattern SP are kept in mind. The appearance, especially the shape of the bead weld, can be finely controlled.

<Modification 3>
14A to 14C show the first to third scanning patterns of the laser beam according to this modification.

The scanning pattern of the laser beam LB is not limited to the patterns shown in the first embodiment and the second modification. For example, as shown in FIG. 14A, it may be a composite pattern of two circular patterns arranged so as to be in contact with each other at the origin O1 and sandwiching the Y axis. Further, as shown in FIG. 14B, it may be a composite pattern of elliptical patterns arranged so as to be in contact with each other at the origin O1 and sandwiching the Y axis. In the example shown in FIG. 14B, in each of the two elliptical patterns, the long axis is in the Y direction and the short axis is in the X direction. However, the long axis may be in the X direction and the short axis may be in the Y direction. As shown in 14C, it may be a composite pattern of two rhombus patterns arranged so as to be in contact with each other at the origin O1 and sandwiching the Y axis. The size of each of the two annular patterns can also be changed as appropriate.

That is, the scanning pattern of the laser beam LB in this modification may be a pattern in which two annular patterns are in contact with each other at the origin O1 and are continuous, and is not limited to the examples shown in FIGS. 14A to 14C and the modifications thereof. For example, in the scanning patterns SP4 to SP6, the amplitude at the time of vertical operation may be changed so as to be vertically asymmetric. These patterns can be obtained by driving the first mirror 41a and the second mirror 42a according to a predetermined drive pattern, respectively.

By configuring the laser welding method and the laser welding apparatus 100 in this way, it is possible to obtain the same effect as that of the configurations shown in the first embodiment and the first and second modifications.

Further, when the configurations shown in the first embodiment, the first and second modifications, and the present modifications are put together, it can be said that the laser welding method of the present disclosure has the following configurations. That is, in the laser welding method of the present disclosure, the work 200 is spot-welded by scanning the laser beam LB two-dimensionally and irradiating the surface of the work 200 while advancing the laser beam LB along the spot pattern SP. It has a welding step to do.

The spot pattern SP is an annular pattern or a linear pattern in which one end and the other end are equidistant from a predetermined center point O.

In the welding step, the laser beam LB is scanned so that the scanning pattern SP1 (predetermined pattern) is drawn on the surface of the work 200. At the same time, the laser beam LB is scanned so that the origin O1 of the scanning pattern SP1 passes over the spot pattern SP1.

Further, the scanning pattern SP1 has the same or different widths on both sides of the spot pattern SP with the tangent line of the spot pattern SP at the origin O1 interposed therebetween.

By doing so, even when a gap (= g1) exists between the first plate material 210 and the second plate material 220, the first plate material 210 and the second plate material 220 are surely secured while reducing spatter. Spot welding can be performed, and the strength of the welded part can be increased. In addition, the shape of the formed weld bead can be improved.

The laser welding apparatus 100 of the present disclosure includes a laser oscillator 10 that generates a laser beam LB, a laser head 30 that receives the laser beam LB and irradiates the work 200, an operation of the laser head 30, and an output P of the laser beam LB. At least includes a controller 50 for controlling the above.

The laser head 30 has a laser light scanner 40 that scans the laser light LB in each of the X direction (first direction) and the Y direction (second direction) intersecting the X direction.

The controller 50 drives and controls the laser light scanner 40 so as to scan the laser light LB two-dimensionally while advancing the laser light LB along the spot pattern SP.

Further, the controller 50 drives and controls the laser light scanner 40 so that the laser light LB draws the scanning pattern SP1 on the surface of the work 200 and the origin O1 of the scanning pattern SP1 passes over the spot pattern SP.

The spot pattern SP is an annular pattern or a linear pattern in which one end and the other end are equidistant from a predetermined center point O. Further, the scanning pattern SP1 has the same width or a different width on both sides of the spot pattern SP with the tangent line of the spot pattern SP at the origin O1 interposed therebetween.

By configuring the laser welding apparatus 100 in this way, the irradiation width of the laser beam lb is widened across the spot pattern SP, and the irradiation amount of the laser beam LB on the inside and outside of the spot pattern SP in the radial direction is equalized. Can be closer to or different. Further, even when a gap (= g1) exists between the first plate material 210 and the second plate material 220, the first plate material 210 and the second plate material 220 can be reliably spot-welded to the welded portion. The strength can be increased. In addition, the shape of the formed weld bead can be improved.

(Other embodiments)
It is also possible to appropriately combine the components shown in the first to third embodiments and the first to third embodiments to form a new embodiment. For example, it is also possible to scan the laser beam LB so as to draw the scanning pattern shown in the modified examples 2 and 3 along the spot pattern SP shown in the modified example 1.

Further, in the modifications 2 and 3, for example, the laser beam LB may be scanned so as to pass from the origin O to the drawing position C → B → A → O → F → E → D → O during one cycle. ..

In the example shown in FIG. 1, the condenser lens 34 is arranged in the front stage of the laser light scanner 40, but is in the rear stage of the laser light scanner 40, that is, the light emission port of the laser light scanner 40 and the laser head 30. It may be arranged between.

Further, the laser beam LB is vibrated in a chordal wave shape having a first frequency along the welding direction WD, and is vibrated in a chordal wave shape having a second frequency along the direction intersecting the welding direction WD. The scanning pattern of may be a laserge pattern. In this case, it goes without saying that the amplitudes a and b of the first mirror 41a and the second mirror 42a, the frequencies n and m of the first mirror 41a and the second mirror 42a, and the phase φ are appropriately changed.

Since the laser welding method of the present disclosure can widen the irradiation width of the laser beam while ensuring the penetration depth, it is useful for spot welding a work in which two plate materials are overlapped.

10 Laser oscillator 20 Optical fiber 30 Laser head 31 Housing 32 Collimation lens 33 Reflective mirror 34 Condensing lens 40 Laser optical scanner 41 1st galvano mirror 41a 1st mirror 41b 1st rotating shaft 41c 1st drive unit 42 2nd galvano mirror 42a 2nd mirror 42b 2nd rotating shaft 42c 2nd drive unit 50 Controller 60 Manipulator 200 Work 210 1st plate material 220 2nd plate material 311 Molten metal 312 Molten pond

Claims (14)

A welding step for spot welding the work is provided by scanning the laser light two-dimensionally and irradiating the surface of the work while the laser light is traveling along the spot pattern.
In the welding step, the laser beam is scanned so that a predetermined pattern is drawn on the surface of the work and the origin of the predetermined pattern passes over the spot pattern.
The spot pattern is an annular pattern or a linear pattern in which one end and the other end are equidistant from a predetermined center point.
A laser welding method characterized in that the predetermined pattern has the same width or a different width on both sides of the spot pattern with a tangent line of the spot pattern at the origin interposed therebetween. In the laser welding method according to claim 1,
A laser welding method characterized in that a center line passing through the origin of the predetermined pattern is orthogonal to a tangent line of the spot pattern at the origin. In the laser welding method according to claim 1 or 2.
The predetermined pattern is a figure eight or ∞-shaped resage pattern.
In the welding step, the laser beam is vibrated in a sine wave shape having a first frequency along the welding direction which is the traveling direction of the laser beam, and a sine having a second frequency along the direction intersecting the welding direction. A laser welding method characterized in that the laser beam is scanned so as to draw the resage pattern on the surface of the work by vibrating in a wavy shape. In the laser welding method according to claim 3,
A laser welding method characterized in that the ratio of the first frequency to the second frequency is 1: 2 or 2: 1. In the laser welding method according to any one of claims 1 to 4.
The spot pattern is. An annular pattern, or a partially open annular pattern,
A laser welding method characterized in that the size of a portion of the predetermined pattern irradiated to the outside of the spot pattern is larger than that of a portion irradiated to the inside of the spot pattern. A laser oscillator that generates laser light and
A laser head that receives the laser beam and irradiates it toward the work,
At least a controller for controlling the operation of the laser head is provided.
The laser head has a laser beam scanner that scans the laser beam in each of a first direction and a second direction intersecting the first direction.
The controller drives and controls the laser beam scanner so as to scan the laser beam two-dimensionally while advancing the laser beam along the spot pattern.
Further, the controller drives and controls the laser light scanner so that the laser light draws a predetermined pattern on the surface of the work and the origin of the predetermined pattern passes over the spot pattern.
The spot pattern is an annular pattern or a linear pattern in which one end and the other end are equidistant from a predetermined center point.
The laser welding apparatus, wherein the predetermined pattern has the same width or a different width on both sides of the spot pattern with the tangent line of the spot pattern at the origin interposed therebetween. In the laser welding apparatus according to claim 6,
A laser welding apparatus characterized in that a center line passing through the origin of the predetermined pattern is orthogonal to a tangent line of the spot pattern at the origin. In the laser welding apparatus according to claim 6 or 7.
The predetermined pattern is a figure eight or ∞-shaped resage pattern.
The controller vibrates the laser beam in a sinusoidal shape having a first frequency along the welding direction which is the traveling direction of the laser beam, and has a sinusoidal shape having a second frequency along the direction intersecting the welding direction. A laser welding apparatus characterized in that the laser light scanner is driven and controlled so as to draw the resage pattern on the surface of the work by vibrating the laser light scanner. In the laser welding apparatus according to claim 8,
A laser welding apparatus characterized in that the ratio of the first frequency to the second frequency is 1: 2 or 2: 1. In the laser welding apparatus according to any one of claims 6 to 9.
The spot pattern is. An annular pattern, or a partially open annular pattern,
The controller drives and controls the laser light scanner so that the size of the portion of the predetermined pattern irradiated to the outside of the spot pattern is larger than the size of the portion irradiated to the outside of the spot pattern. A laser welding device characterized by. In the laser welding apparatus according to any one of claims 6 to 10.
Further equipped with a manipulator to which the laser head is attached
The controller controls the operation of the manipulator, and the controller controls the operation of the manipulator.
The manipulator is a laser welding apparatus characterized by moving the laser head in a predetermined direction with respect to the surface of the work. In the laser welding apparatus according to any one of claims 6 to 11.
The laser oscillator and the laser head are connected by an optical fiber.
A laser welding apparatus characterized in that the laser light is transmitted from the laser oscillator to the laser head through the optical fiber. The laser welding apparatus according to any one of claims 6 to 12.
The laser light scanner is composed of a first galvano mirror that scans the laser light in the first direction and a second galvano mirror that scans the laser light in a second direction intersecting the first direction. Laser welding equipment characterized by being In the laser welding apparatus according to any one of claims 6 to 13.
The laser head further has a focal position adjusting mechanism.
The laser welding apparatus is characterized in that the focal position adjusting mechanism is configured to change the focal position of the laser beam along a direction intersecting the surface of the work.

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