JP2024072000A - Laser processing device and laser processing method - Google Patents

Abstract

[Problem] To provide a laser processing device capable of reducing the occurrence of spatters even when the laser processing conditions are changed in hybrid laser processing. [Solution] A laser processing device 1000 includes a first laser oscillator 100 that emits a first laser beam LB1, a second laser oscillator 200 that emits a second laser beam LB2, and a laser head 500 that receives the first and second laser beams LB1 and LB2 and irradiates the workpiece 900 with the first and second laser beams LB1 and LB2. The laser head 500 includes a housing 510 and a first optical path changing mechanism 540 disposed therein. The first optical path changing mechanism 540 is disposed in the optical path of the first laser beam LB1. The first laser beam LB1 is irradiated forward of the second laser beam LB2. The first optical path changing mechanism 540 changes the optical path of the first laser beam LB1 emitted from an emission port 513 in accordance with the laser welding conditions. [Selected Figure] FIG.

Description

This disclosure relates to a laser processing device and a laser processing method, and in particular to a hybrid laser processing device and a laser processing method that use a short-wavelength laser beam and a long-wavelength laser beam.

Laser welding has been known as one of the conventional methods for welding metal materials such as iron and copper. Laser welding is a welding method in which a laser beam is irradiated onto a predetermined location of the workpiece to be welded, and the workpiece is melted by the energy of the laser beam. A pool of molten metal called a molten pool is formed in the welded area irradiated with the laser beam, and the molten pool subsequently solidifies to form a solidified area. Laser welding is performed by irradiating the workpiece with a moving laser beam along a predetermined weld line.

In recent years, the output of laser oscillators has improved, making it possible to perform laser welding using high-power laser light. By using high-power laser light, the tact time of the welding process can be reduced. In addition, welding can be easily performed even when the workpiece is thick, at 8 mm or more.

However, when a high-power laser beam is used, the occurrence of spatter due to scattering of molten metal becomes significant. The spatter adheres to the vicinity of the welding point and is one of the causes of poor welding. In order to reduce the occurrence of spatter, a method has been proposed in which sub-beams with low power density are irradiated around a main beam with high power density, and the main beam is irradiated onto a molten pool formed by the sub-beams to perform laser welding (see, for example, Patent Document 1).

It is well known that the light absorption rate differs depending on the type of metal material. For example, copper has a low absorption rate for light in the near-infrared wavelength range that is often used in laser welding. For this reason, a method has been proposed in which laser welding is performed by simultaneously irradiating the workpiece with laser light in a wavelength range with high absorption rate, such as blue laser light and near-infrared laser light (see, for example, Patent Documents 2 and 3). This type of laser welding is generally called hybrid laser welding.

Patent No. 6935484 International Publication No. 2021/182643 International Publication No. 2021/193855

However, according to the research of the present inventors, it was found that in hybrid laser welding, the state of spatter generation changes depending on the laser welding conditions. For example, when laser welding is performed with the power of blue laser light and the power of laser light in the near-infrared wavelength range fixed, it was found that the amount of spatter adhering to the workpiece increases when the welding speed decreases. This phenomenon is not reported in Patent Documents 1 to 3.

In addition to laser welding, similar problems are likely to occur when performing hybrid laser processing such as laser cutting.

The present disclosure has been made in consideration of these points, and its purpose is to provide a laser processing device and a laser processing method that can reduce the occurrence of spatter even when the laser processing conditions are changed in hybrid laser processing.

In order to achieve the above object, the laser processing apparatus according to the present disclosure is a laser processing apparatus including at least a first laser oscillator that emits a first laser beam, a second laser oscillator that emits a second laser beam having a longer wavelength than the first laser beam, a laser head that receives the first laser beam and the second laser beam, respectively, and emits them toward a workpiece, and a movement mechanism that moves one of the workpiece and the laser head relative to the other, wherein the laser head has at least a housing, a first optical path changing mechanism, and a plurality of optical components arranged inside the housing, and the housing has a first entrance port through which the first laser beam is incident, a second entrance port through which the second laser beam is incident, and an exit port through which the first laser beam and the second laser beam are respectively emitted. , the first optical path changing mechanism is disposed in the optical path of the first laser light between the first entrance and the exit, and when the workpiece is laser processed, the movement mechanism moves one of the workpiece and the laser head relative to the other, and the first laser light is irradiated forward of the second laser light in a direction along a predetermined processing line, simultaneously with the second laser light, and the first optical path changing mechanism changes the optical path of the first laser light emitted from the exit according to laser processing conditions, and the laser processing conditions include at least the moving speed of the laser head along the processing line, the power of the second laser light, and the spot diameter of the second laser light irradiated on the workpiece.

The laser processing method according to the present disclosure is a laser processing method for laser processing a workpiece by irradiating the workpiece with a first laser light and a second laser light having a longer wavelength than the first laser light, and includes at least a step of irradiating the first laser light simultaneously with the second laser light and forward of the second laser light in a direction along a predetermined processing line on the surface of the workpiece to laser process the workpiece, and is characterized in that the irradiation position of the first laser light on the surface of the workpiece is changed according to laser processing conditions, and the laser processing conditions include at least the moving speed of the irradiation position of the second laser light along the processing line, the power of the second laser light, and the spot diameter of the second laser light irradiated on the workpiece.

According to the present disclosure, in hybrid laser processing, the occurrence of spatter can be reduced even when the laser processing conditions are changed.

1 is a schematic configuration diagram of a laser processing device according to an embodiment. FIG. 2 is a schematic diagram of a laser head. FIG. 1 is a diagram showing the wavelength dependence of optical absorptance in various metals. 10 is a schematic cross-sectional view showing the state of the workpiece during laser welding using only the second laser light. FIG. 4 is a schematic cross-sectional view showing a state of a workpiece during laser welding using a first laser beam and a second laser beam; FIG. FIG. 11 is a diagram showing the relationship between the type of laser light, the welding speed, and the appearance of the weld bead. 4A and 4B are diagrams illustrating irradiation trajectories of a first laser beam and a second laser beam during laser welding. 13A and 13B are diagrams showing other irradiation trajectories of the first laser beam and the second laser beam during laser welding. FIG. 2 is a diagram showing the appearance of weld beads according to Examples 1 and 2 and a comparative example.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

(Embodiment)
[Configuration of laser processing device]
Fig. 1 shows a schematic configuration diagram of a laser processing apparatus according to this embodiment, and the laser processing apparatus 1000 includes a first laser oscillator 100, a second laser oscillator 200, a first optical fiber 300, a second optical fiber 400, a laser head 500, a robot 600, a first laser controller 710, a second laser controller 720, a robot controller 730, and a stage 800. Note that in Fig. 1, for convenience of explanation, the shape of the laser head 500 is illustrated in a simplified form.

In the following description, the traveling direction of the laser light irradiated from the laser head 500 to the workpiece 900 may be referred to as the Z direction. In addition, in FIG. 1, the direction from the first laser oscillator 100 and the second laser oscillator 200 toward the laser head 500 may be referred to as the X direction, and the direction that intersects with the X direction and the Z direction may be referred to as the Y direction.

When laser processing the workpiece 900, the first laser beam LB1 and the second laser beam LB2 are irradiated along a processing line (not shown) on the surface of the workpiece 900. In this embodiment, laser welding is described as an example of one form of laser processing. In this embodiment, the Y direction is the direction along the processing line, in this case the welding line. Therefore, in the following description, the Y direction may be referred to as the welding direction.

The first laser oscillator 100 emits the first laser light LB1 based on a control signal from the first laser controller 710. The first laser light LB1 is a laser light in the blue wavelength range or the green wavelength range, and in this embodiment, the wavelength λ1 of the first laser light LB1 is 450 nm. In this specification, the "blue wavelength range" refers to a wavelength range of 400 nm or more and 490 nm or less. Also, the "green wavelength range" refers to a wavelength range of 500 nm or more and 560 nm or less. The wavelength range of the first laser light LB1 is not particularly limited to this, and may be shorter than 400 nm.

The first laser oscillator 100 and the laser head 500 are connected by a first optical fiber 300. The first laser light LB1 is transmitted from the first laser oscillator 100 to the laser head 500 via the first optical fiber 300.

The second laser oscillator 200 emits the second laser light LB2 based on a control signal from the second laser controller 720. The second laser light LB2 is a laser light in the near-infrared wavelength range, and in this embodiment, the wavelength λ2 of the second laser light LB2 is 975 nm. In this specification, the "near-infrared wavelength range" refers to a wavelength range of 900 nm or more and 1100 nm or less. The wavelength range of the second laser light LB2 is not particularly limited to this, and may be longer than 1100 nm.

The second laser oscillator 200 and the laser head 500 are connected by a second optical fiber 400. The second laser light LB2 is transmitted from the second laser oscillator 200 to the laser head 500 via the second optical fiber 400.

The first optical fiber 300 transmits the first laser light LB1 emitted from the first laser oscillator 100 to the laser head 500. The second optical fiber 400 transmits the second laser light LB2 emitted from the second laser oscillator 200 to the laser head 500.

The first optical fiber 300 and the second optical fiber 400 each have a known configuration, with a core (not shown) that is an optical waveguide disposed at the axis, and a clad (not shown) that is an optical confinement layer that covers the outer peripheral surface of the core. A protective coating (not shown) is also provided to cover the outer peripheral surface of the clad. Both the core and the clad are made of quartz, but the refractive index of the core is adjusted to be higher than the refractive index of the clad. The number and cross-sectional shape of the cores can be changed as appropriate in each of the first optical fiber 300 and the second optical fiber 400. The cross-sectional shape of the clad can also be changed as appropriate accordingly.

The laser head 500 receives the first laser light LB1 and the second laser light LB2 incident from the first optical fiber 300 and the second optical fiber 400, and further irradiates the first laser light LB1 and the second laser light LB2 toward the workpiece 900, respectively. The structure of the laser head 500 will be described in detail later.

The robot 600 has a robot arm 610. The laser head 500 is attached to the tip of the robot arm 610. The robot arm 610 is divided into multiple parts, and each part is provided with a joint shaft 620 at the connecting portion.

Based on a control signal from the robot controller 730, the robot 600 moves the laser head 500 along the welding direction (Y direction) and changes the position of the laser head 500 relative to the workpiece 900. With this operation, the irradiation positions of the first laser beam LB1 and the second laser beam LB2 on the surface of the workpiece 900 move along the welding direction (Y direction), and laser welding is performed.

The first laser controller 710 is connected to the first laser oscillator 100 and controls the operation of the first laser oscillator 100. Specifically, the first laser controller 710 controls the timing of starting and stopping the emission of the first laser light LB1, the emission time, and the power of the first laser light LB1.

The second laser controller 720 is connected to the second laser oscillator 200 and controls the operation of the second laser oscillator 200. Specifically, the second laser controller 720 controls the timing of starting and stopping the emission of the second laser light LB2, the emission time, and the power of the second laser light LB2.

In this embodiment, the power of the first laser light LB1 is set to be lower than the power of the second laser light LB2. The difference or ratio between the power of the first laser light LB1 and the power of the second laser light LB2 is set appropriately depending on the material and thickness of the workpiece 900 to be laser welded. This will be described further below.

The robot controller (controller) 730 is connected to the robot 600 and the laser head 500, and controls the operation of the robot 600 and the operation of the first optical path changing mechanism 540 described later. Specifically, the robot controller 730 controls the rotation speed and rotation amount of a motor (not shown) provided on the joint shaft 620 that connects each part of the robot arm 610. As a result, the laser head 500 attached to the tip of the robot arm 610 moves along the welding direction at a predetermined moving speed V. Furthermore, the first laser light LB1 and the second laser light LB2 emitted from the laser head 500 are irradiated on the surface of the workpiece 900 along the welding direction at the moving speed V. In the following description, the moving speed V of the laser head 500 along the welding line may be referred to as the welding speed V.

The above-mentioned functions of the first laser controller 710, the second laser controller 720, and the robot controller 730 are realized by executing a predetermined welding program on the hardware that each of them possesses. The hardware is composed of one or more CPUs (Central Processing Units) and memories. The memories are, for example, semiconductor memories such as RAMs (Random Access Memory) and SSDs (Solid State Drives). The memories may also be ROMs (Read Only Memory) or RAMs built into the CPU.

The first laser controller 710, the second laser controller 720, and the robot controller 730 may be connected to a higher-level controller (not shown). In this case, execution commands based on a welding program executed by the higher-level controller are sent to the first laser controller 710, the second laser controller 720, and the robot controller 730, respectively, to execute predetermined processing. The first laser controller 710, the second laser controller 720, and the robot controller 730 may be integrated into a single controller.

The robot controller 730 may also be divided into a controller that controls the operation of the laser head 500 and a controller that controls the operation of the robot 600. However, even in this case, the respective controllers work together to control the operation of the laser head 500 and the robot 600, respectively.

When the workpiece 900 is placed on the stage 800, the position of the workpiece 900 relative to the laser processing device 1000 is determined. In this embodiment, the stage 800 is fixed and stationary in one location, but by providing the stage 800 with a stage movement mechanism (not shown), the stage 800 may be configured to be movable along an XY plane that includes the X and Y directions within the plane. In this case, the position of the robot 600, in other words, the position of the laser head 500, may be fixed.

[Laser head configuration]
Fig. 2 shows a schematic configuration diagram of a laser head, and the laser head 500 has a housing 510 and a plurality of optical components arranged therein. Note that, for the sake of convenience, the shapes of the components constituting the laser head 500 are shown in a simplified form in Fig. 2. Also, components other than those shown in Fig. 2 may be arranged inside the housing 510 or attached to the outside of the housing 510.

The housing 510 has a first entrance 511, a second entrance 512, and an exit 513. The first entrance 511 is an entrance for the first laser light LB1 to which the first optical fiber 300 is connected. The second entrance 512 is an entrance for the second laser light LB2 to which the second optical fiber 400 is connected. The exit 513 is an exit for the first laser light LB1 and the second laser light LB2. The first laser light LB1 and the second laser light LB2, which are respectively incident from the first entrance 511 and the second entrance 512, are emitted from the exit 513 toward the workpiece 900.

Inside the housing 510, a first collimating lens 520, a second collimating lens 530, a first optical path changing mechanism 540, a beam combiner 550, and a condenser lens 560 are arranged. Also, inside the housing 510, a protective glass 570 is arranged to cover the exit port 513.

The first collimating lens 520 converts the first laser light LB1 emitted from the output end of the first optical fiber 300 into a parallel beam. The second collimating lens 530 converts the second laser light LB2 emitted from the output end of the second optical fiber 400 into a parallel beam.

The first optical path changing mechanism 540 is disposed between the first entrance 511 and the exit 513, in the optical path of the first laser light LB1. The first optical path changing mechanism 540 is a MEMS mirror having a mirror 541, a piezo stage 542, and a piezo actuator 543.

The mirror 541 reflects the first laser light LB1 that has passed through the first collimator lens 520 toward the beam combiner 550. The mirror 541 is attached integrally to the piezo stage 542, and the piezo actuator 543 is attached to the piezo stage 542. By driving the piezo actuator 543, the piezo stage 542 and the mirror 541 tilt around an axis parallel to the Y direction, changing the optical axis of the first laser light LB1 reflected by the mirror 541 within a predetermined range. As a result, the first laser light LB1 emitted from the emission port 513 is irradiated onto the surface of the workpiece 900 while being scanned in a direction intersecting the Y direction, which is the welding direction.

The first optical path changing mechanism 540 is not limited to the structure shown in FIG. 2. For example, the first optical path changing mechanism 540 may be a galvanometer mirror that tilts around an axis parallel to the Y direction. In addition, in consideration of the case where the X direction and the Y direction are each set as the welding direction, the first optical path changing mechanism 540 may be a two-axis MEMS mirror. In this case, the first laser light LB1 emitted from the emission port 513 is irradiated onto the surface of the workpiece 900 while being scanned in a direction intersecting the X direction or a direction intersecting the Y direction. In this case, the first optical path changing mechanism 540 may also be a galvanometer mirror that tilts around an axis parallel to the Y direction and an axis parallel to the X direction.

The beam combiner 550 is a so-called wavelength selection mirror, and is designed to reflect the first laser light LB1 while transmitting the second laser light LB2. In the example shown in FIG. 2, the first laser light LB1 reflected by the beam combiner 550 and the second laser light LB2 transmitted through the beam combiner 550 are directed toward the exit port 513 so that their optical axes coincide with each other. However, as will be described later, the first laser light LB1 is irradiated in front of the second laser light LB2 along the Y direction. To achieve this, for example, the inclination angle of the beam combiner 550 relative to the optical axis of the first laser light LB1 incident on the beam combiner 550 is adjusted in advance, or the position of the mirror 541 of the first optical path changing mechanism 540 is adjusted.

The focusing lens 560 focuses the first laser light LB1 and the second laser light LB2. The first laser light LB1 and the second laser light LB2 that pass through the focusing lens 560 are focused into approximately circular spots SP1 and SP2, respectively, on the surface of the workpiece 900 (see Figures 6A and 6B).

The protective glass 570 prevents spatter and fumes generated during laser welding from entering the inside of the housing 510. This protects the optical components arranged inside the housing 510 and prevents a decrease in the power and beam quality of the first laser light LB1 and the second laser light LB2 emitted from the emission port 513.

[About hybrid laser welding method]
Fig. 3 shows the wavelength dependence of light absorptivity in various metals. Fig. 4A is a schematic cross-sectional view showing the state of a workpiece during laser welding using only the second laser beam. Fig. 4B is a schematic cross-sectional view showing the state of a workpiece during laser welding using the first laser beam and the second laser beam.

In laser welding, when a laser beam is irradiated onto a metal workpiece 900, the laser beam is absorbed by the workpiece 900, causing the temperature of the irradiated portion to rise. As the temperature rise continues, the workpiece 900 melts and a molten pool 910 is formed (see FIG. 4A). After the laser beam passes through, the temperature of the molten pool 910 drops rapidly, and the molten pool 910 solidifies to form a solidified portion 930, thereby laser welding the workpiece 900.

In many cases, the power of the laser light is set so that a keyhole 920 (see FIG. 4A) is formed directly below the area irradiated by the laser light. By forming the keyhole 920, the laser light is directly irradiated inside the workpiece 900. This allows the molten pool 910 to be formed deep, resulting in deep penetration.

Generally, when light is irradiated onto a metal, the proportion of the light absorbed by the metal, that is, the light absorptance, varies depending on the wavelength of the light. Furthermore, the wavelength dependency of the light absorptance varies greatly depending on the metal material.

For example, as shown in Figure 3, in iron and nickel, the light absorptance increases as the wavelength becomes shorter, but the rate of change in light absorptance with respect to wavelength is gradual. Taking iron as an example, the light absorptance at the wavelength λ2 (= 975 nm) of the second laser light LB2 is 40%, and the light absorptance at the wavelength λ1 (= 450 nm) of the first laser light LB1 is about 45%.

On the other hand, in copper, the light absorption rate increases rapidly when the wavelength becomes shorter than 800 nm. While the light absorption rate at the wavelength λ2 of the second laser light LB2 is less than 10%, the light absorption rate at the wavelength λ1 of the first laser light LB1 increases to about 60%.

For this reason, if the workpiece 900 is a copper plate, and if an attempt is made to laser weld the workpiece 900 using only the second laser beam LB2, in order to form the molten pool 910, it is necessary to set the power of the second laser beam LB2 high in accordance with the low light absorption rate.

However, the light absorption rate also varies greatly depending on the temperature of the workpiece 900, particularly whether the workpiece 900 is in a solid or liquid state, and the light absorption rate increases significantly when the workpiece 900 is in a liquid state. In this case, as shown in FIG. 4A, the light absorption rate of the second laser light LB2 in the molten pool 910 increases significantly, and the temperature of the molten pool 910 increases rapidly. This causes bumping in the molten pool 910, and the molten metal ejected by convection toward the surface of the workpiece 900 adheres to the surface of the workpiece 900, resulting in spattering.

As mentioned above, a hybrid laser welding method using both the first laser beam LB1 and the second laser beam LB2 has been proposed to suppress the occurrence of such spatter.

In this laser welding method, as shown in FIG. 4B, a first laser beam LB1 having a wavelength λ1 and a second laser beam LB2 having a wavelength λ2 are irradiated in a superimposed state on the surface of the workpiece 900. At this time, the spot diameter of the first laser beam LB1 is set to be larger than the spot diameter of the second laser beam LB2 on the surface of the workpiece 900. Also, the power of the first laser beam LB1 is set to be smaller than the power of the second laser beam LB2. Note that the spot diameters of the first laser beam LB1 and the second laser beam LB2 correspond to the beam diameters when the focal points of the first laser beam LB1 and the second laser beam LB2 are located on the surface of the workpiece 900, respectively.

By irradiating the first laser beam LB1, which has a high light absorption rate for the copper workpiece 900, with a wide spot diameter, a molten pool 910 that is wide and has a shallow penetration depth is formed on the workpiece 900. In this state, the second laser beam LB2 is irradiated to the molten pool 910. The power of the first laser beam LB1 is set low enough that a keyhole 920 is not formed. In other words, the welding mode using the first laser beam LB1 is heat conduction welding. However, a shallow keyhole 920 may be formed.

In addition, because the power of the second laser beam LB2 is greater than the power of the first laser beam LB1, a molten pool 910 is formed that is deeper than the molten pool 910 formed by the first laser beam LB1. As a result, a deep penetration depth is obtained.

The spot diameter of the first laser beam LB1 is larger than the spot diameter of the second laser beam LB2. As a result, when the second laser beam LB2 is irradiated onto the molten pool 910 formed by the first laser beam LB1, the opening of the keyhole 920 is widened, and convection in the molten metal toward the surface of the workpiece 900 is suppressed. This reduces spatter.

[Findings that led to the present disclosure]
However, the inventors of the present application discovered that in laser welding using the first laser light LB1 and the second laser light LB2, the size of the molten pool 910 formed varies greatly depending on the laser welding conditions, such as the welding speed and the power of the second laser light LB2.

Figure 5 is a diagram showing the relationship between the type of laser light, the welding speed, and the appearance of the weld bead. The upper part of Figure 5 shows the weld bead 940 formed when only the first laser light LB1 is irradiated onto the workpiece 900, and the lower part shows the weld bead 940 formed when the first laser light LB1 and the second laser light LB2 are irradiated onto the workpiece 900 simultaneously.

As is clear from FIG. 5, when only the first laser beam LB1 was irradiated, the width W1 of the weld bead 940 formed on the workpiece 900 was only about 86% even when the welding speed V increased from 50 mm/sec to 150 mm/sec. The width W1 corresponds to the size of the molten pool 910 formed by irradiation with the first laser beam LB1. With the first laser beam LB1 under conditions of low power (800 W) and large beam diameter (400 μm), i.e., low power density, the amount of heat input to the workpiece 900 itself was small, and the change in the amount of heat input to the workpiece 900 with the change in welding speed V was small, which is thought to be why the change in width W1 was small.

On the other hand, when the first laser beam LB1 and the second laser beam LB2 were irradiated simultaneously, as the welding speed V increased from 50 mm/sec to 150 mm/sec, the width W2 of the weld bead 940 formed on the workpiece 900 was significantly narrowed to about 62%. In other words, it was found that as the welding speed V decreased, the width W2 of the weld bead 940 significantly increased.
The second laser beam LB2 has a higher power (1900 W) and a smaller beam diameter (40 μm) than the first laser beam LB1. In other words, the second laser beam LB2 has a higher power density than the first laser beam LB1. For this reason, it is considered that the change in the amount of heat input to the workpiece 900 increases with the change in the welding speed V.

In other words, it was believed that the increase in width W2 of the weld bead 940 with a decrease in welding speed V was due to the molten pool 910 formed by irradiation with the second laser beam LB2 being larger than the molten pool 910 formed by irradiation with the first laser beam LB1. In addition, although not shown, it was confirmed that such a phenomenon actually occurred when a high-speed video was taken of the surface of the workpiece 900 during laser welding.

When the molten pool 910 formed by irradiation with the second laser beam LB2 becomes larger than the molten pool 910 formed by irradiation with the first laser beam LB1, spatter is more likely to occur due to the convection of the molten pool 910 described above. In addition, considering the difference in the amount of heat input to the workpiece 900 per unit time, it is thought that spatter is more likely to occur when not only the welding speed V but also the power ratio of the second laser beam LB2 to the first laser beam LB1 increases.

In this way, it was found that changes in the laser welding conditions resulted in the reduction of spatter, one of the benefits of hybrid laser welding, being no longer obtainable.

The inventors of the present application have further studied this matter, and as described below, in this embodiment, they propose a laser welding method in which the first laser beam LB1 is irradiated in front of the second laser beam LB2 along the welding direction. Furthermore, in this laser welding method, the first laser beam LB1 is periodically scanned at a first amplitude in a direction intersecting the welding direction, thereby forming a wide molten pool 910 in front of the irradiation position of the second laser beam LB2, thereby suppressing the occurrence of spatter. The details of this method are described below.

[Laser welding method]
FIG. 6A shows irradiation trajectories of the first laser beam and the second laser beam during laser welding, and FIG. 6B shows another irradiation trajectory of the first laser beam and the second laser beam during laser welding.

In the example shown in FIG. 6A, the first laser light LB1 is irradiated so as to be positioned in front of the second laser light LB2 along the welding direction, and the first laser light LB1 is periodically scanned along the X direction. In this manner, the first laser light LB1 is first irradiated onto the workpiece 900 to form a molten pool 910 of a predetermined size. Next, the second laser light LB2, which has a power greater than that of the first laser light LB1, is irradiated onto the molten pool 910.

In this embodiment, the distance L between the irradiation position of the first laser light LB1 and the irradiation position of the second laser light LB2 along the welding direction is defined as the distance between the center of the spot SP2 of the second laser light LB2 and the center of the spot SP1 of the first laser light LB1 where a virtual line extending from the center along the welding direction intersects.

The laser welding conditions, specifically, the power and welding speed V of the second laser light LB2, and the size of the molten pool 910 formed by the first laser light LB1 are appropriately changed. For example, when the power of the second laser light LB2 is large relative to the power of the first laser light LB1, the distance L is made large so that the molten pool 910 formed by the second laser light LB2 does not exceed the molten pool 910 formed by the first laser light LB1. On the other hand, when the power of the second laser light LB2 is reduced, the distance L is made small so that the molten pool 910 formed by the first laser light LB1 does not solidify.

As described above, the distance L may be adjusted by previously adjusting the tilt angle of the beam combiner 550. Alternatively, the distance L may be adjusted by adjusting the position of the mirror 541 of the first optical path changing mechanism 540. In the latter case, the distance L may be previously adjusted by adjusting the DC voltage applied to the piezoelectric actuator 543. In this way, the distance L can be easily changed even if the power of the first laser light LB1 or the second laser light LB2 is changed depending on the type or material of the workpiece 900.

The first amplitude A1 shown in FIG. 4A is the amount of change in the irradiation position of the first laser light LB1 in the X direction. In this embodiment, the first amplitude A1 is the distance between the center of the spot SP1 of the first laser light LB1 at one end in the X direction and the center of the spot SP1 of the first laser light LB1 at the other end.

The first amplitude A1 is also changed according to the laser welding conditions. For example, as the welding speed V decreases or the power of the second laser light LB2 increases, the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the first amplitude A1 becomes longer. Specifically, the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 in response to a control signal from the robot controller 730 so that the first amplitude A1 becomes longer.

In other words, the larger the molten pool 910 formed by the second laser beam LB2, the longer the first amplitude A1 is. In this way, the occurrence of spatter can be reduced during hybrid laser welding.

In addition, when the reciprocal of the period in which the irradiation position of the first laser light LB1 changes is the first frequency f1, the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the first frequency f1 increases as the welding speed V increases or the power of the second laser light LB2 decreases. Specifically, the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 in response to a control signal from the robot controller 730 so that the first frequency f1 increases. In this way, in hybrid laser welding, the molten pool 910 can be reliably formed in front of the irradiation position of the second laser light LB2, and the occurrence of spatter can be reduced.

The scanning trajectory of the first laser light LB1 is not limited to the example shown in FIG. 4A. For example, as shown in FIG. 4B, the first laser light LB1 may be scanned in an arc shape so as to intersect with the welding direction. The distance R shown in FIG. 4B corresponds to the distance L shown in FIG. 4A. The method of changing the first amplitude A1 and the first frequency f1 according to the laser welding conditions is the same as that described using the example shown in FIG. 4A.

[Effects, etc.]
As described above, the laser processing apparatus 1000 according to this embodiment includes at least the first laser oscillator 100 that emits the first laser beam LB1, the second laser oscillator 200 that emits the second laser beam LB2 having a longer wavelength than the first laser beam LB1, and the laser head 500 that receives the first laser beam LB1 and the second laser beam LB2 and emits them toward the workpiece 900. The laser processing apparatus 1000 also includes a robot 600 to which the laser head 500 is attached and which moves the laser head 500 relative to the workpiece 900.

The laser head 500 has at least a housing 510, a first optical path changing mechanism 540, and a plurality of optical components arranged inside the housing 510. The plurality of optical components includes at least a first collimating lens 520, a second collimating lens 530, a beam combiner 550, a condensing lens 560, and a protective glass 570.

The housing 510 is provided with a first inlet 511 through which the first laser light LB1 is incident, a second inlet 512 through which the second laser light LB2 is incident, and an outlet 513 through which the first laser light LB1 and the second laser light LB2 are each emitted.

The first optical path changing mechanism 540 is disposed in the optical path of the first laser light LB1 between the first entrance 511 and the exit 513.

When laser welding the workpiece 900, the robot 600 moves the laser head 500 along a predetermined weld line, and the first laser light LB1 is irradiated simultaneously with the second laser light LB2 and in a direction along the weld line, ahead of the second laser light LB2.

The first optical path changing mechanism 540 changes the optical path of the first laser light LB1 emitted from the emission port 513 according to the laser welding conditions.

The first optical path changing mechanism 540 operates in response to a control signal from the robot controller 730. In other words, the laser processing apparatus 1000 further includes a robot controller (controller) 730 that controls the operation of at least the first optical path changing mechanism 540. The robot controller 730 operates the first optical path changing mechanism 540 to change the optical path of the first laser light LB1 emitted from the emission port 513 in accordance with the laser welding conditions.

The above-mentioned laser welding conditions include at least the movement speed V of the laser head 500 along the weld line, i.e., the welding speed V, and the power of the second laser light LB2.

The spot diameters of the first laser light LB1 and the second laser light LB2 irradiated to the workpiece 900 each affect the size of the molten pool 910. In addition, considering that the power of the first laser light LB1 is lower than the power of the second laser light LB2 and the spot diameter of the first laser light LB1 is larger than the spot diameter of the second laser light LB2, the power and spot diameter of the second laser light LB2 greatly affect the occurrence of spatter.

In view of this, the laser welding conditions related to changing the optical path of the first laser beam LB1 emitted from the emission port 513 also include the spot diameter (beam diameter) of the second laser beam LB2.

The first optical path changing mechanism 540 also periodically changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 in a direction intersecting the weld line according to the laser welding conditions. In other words, the robot controller 730 controls the operation of the first optical path changing mechanism 540 so as to periodically change the irradiation position of the first laser light LB1 on the surface of the workpiece 900 in a direction intersecting the weld line according to the laser welding conditions.

By configuring the laser processing device 1000 in this manner, the size of the molten pool 910 formed on the workpiece 900 by the first laser beam LB1 can be changed relative to the size of the molten pool 910 formed on the workpiece 900 by the second laser beam LB2.

As a result, even if the laser welding conditions are changed, the molten pool 910 formed on the workpiece 900 by the first laser beam LB1 can be made larger than the molten pool 910 formed on the workpiece 900 by the second laser beam LB2. As a result, spatter generated during laser welding can be reduced.

In addition, the desired size of the molten pool 910 is formed by the first laser beam LB1, while the power of the second laser beam LB2 is adjusted to match the material and shape of the workpiece 900, thereby obtaining the desired penetration depth. In other words, even for a workpiece 900 made of a material with low light absorption rate for laser beams in the near-infrared wavelength range, such as copper, it is possible to perform the desired laser welding while reducing spatter.

In addition, according to this embodiment, the width of the weld bead 940 formed on the workpiece 900 can be changed by changing the size of the molten pool 910 formed on the workpiece 900 by the first laser light LB1. This allows the width of the weld bead 940 to be appropriately set to match the shape of the workpiece 900.

For example, when it is desired to ensure a gap tolerance between plate materials in butt welding, the above-mentioned first amplitude A1 can be set large to increase the width of the weld bead 940. In addition, by irradiating the first laser light LB1, the width of the weld bead 940 can be ensured while the power and spot diameter of the second laser light LB2 are appropriately set, thereby ensuring the penetration depth and preventing burn-through.

The amount of change in the irradiation position of the first laser light LB1 in the direction intersecting the weld line is defined as the first amplitude A1. At this time, it is preferable that the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the first amplitude A1 becomes longer as the welding speed V decreases or the power of the second laser light LB2 increases.

As the welding speed V decreases or the power of the second laser light LB2 increases, the molten pool 910 formed in the workpiece 900 by the second laser light LB2 becomes larger. Therefore, in such a case, the first amplitude A1 is lengthened to increase the size of the molten pool 910 formed in the workpiece 900 by the first laser light LB1, so that the second laser light LB2 is irradiated into the inside of the molten pool 910. In this way, the bumping of the molten pool 910 and, ultimately, the occurrence of spattering are suppressed.

The reciprocal of the period in which the irradiation position of the first laser light LB1 changes is defined as the first frequency f1. At this time, it is preferable that the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the first frequency f1 increases as the welding speed V increases or the power of the second laser light LB2 decreases.

As the welding speed V increases or the power of the second laser light LB2 decreases, the molten pool 910 formed in the workpiece 900 by the second laser light LB2 becomes smaller. In such a case, the first frequency f1 is increased to ensure that the molten pool 910 is formed in front of the irradiation position of the second laser light LB2 during scanning of the first laser light LB1. In this way, the second laser light LB2 can be irradiated inside the molten pool 910, suppressing the bumping of the molten pool 910 and the occurrence of spattering.

It is preferable that the first optical path changing mechanism 540 changes the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the distance L or distance R between the irradiation position of the first laser light LB1 and the irradiation position of the second laser light LB2 in the direction along the weld line becomes longer as the welding speed V decreases or the power of the second laser light LB2 increases.

As described above, when the power of the second laser light LB2 is large relative to the power of the first laser light LB1, the molten pool 910 formed by the second laser light LB2 may exceed the molten pool 910 formed by the first laser light LB1. This phenomenon may also occur when the welding speed V is low. Therefore, by increasing the distance L or the distance R, the molten pool 910 formed by the second laser light LB2 can be prevented from exceeding the molten pool 910 formed by the first laser light LB1. This suppresses the bumping of the molten pool 910 during laser welding, and thus the occurrence of spatter. Note that this method is not adopted when adjusting the distance L or the distance R by changing the inclination angle of the beam combiner 550.

It goes without saying that the robot controller (controller) 730 controls the operation of the first optical path changing mechanism 540, causing the first optical path changing mechanism 540 to perform the various operations described above.

The laser processing apparatus 1000 preferably further includes a first optical fiber 300 connected to the first inlet 511 and transmitting the first laser light LB1 to the laser head 500, and a second optical fiber 400 connected to the second inlet 512 and transmitting the second laser light LB2 to the laser head 500.

In this way, laser welding can be performed on a workpiece 900 that is located far away from the first laser oscillator 100 and the second laser oscillator 200.

The robot controller (controller) 730 controls the operation of the robot 600 in addition to the operation of the first optical path changing mechanism 540.

The first optical path changing mechanism 540 changes the optical path of the first laser light LB1 emitted from the emission port 513 in conjunction with the operation of the robot 600 in response to a control signal from the robot controller 730.

As mentioned above, the welding speed V corresponds to the movement speed V of the laser head 500, which is moved relative to the workpiece 900 by operating the robot 600. Also, as mentioned above, the welding speed (movement speed) V has a large effect on the size of the molten pool 910 formed by the second laser light LB2, and thus on the occurrence of spatter.

Therefore, it is preferable to operate the first optical path changing mechanism 540 in conjunction with the operation of the robot 600 using a control signal from the robot controller 730 to change the optical path of the first laser beam LB1, in other words, the irradiation position of the first laser beam LB1 on the surface of the workpiece 900. In this way, the size of the molten pool 910 can be appropriately controlled to suppress the occurrence of spatter.

The laser welding method according to this embodiment is a so-called hybrid laser welding method in which a first laser beam LB1 and a second laser beam LB2 having a longer wavelength than the first laser beam LB1 are irradiated onto the workpiece 900 to laser weld the workpiece 900.

This laser welding method includes at least a step of irradiating the first laser light LB1 simultaneously with the second laser light LB2 and in a direction along a predetermined weld line on the surface of the workpiece 900, ahead of the second laser light LB2, to laser process the workpiece 900.

In addition, in this step, the irradiation position of the first laser light LB1 on the surface of the workpiece 900 is changed according to the laser welding conditions. More specifically, the irradiation position of the first laser light LB1 on the surface of the workpiece 900 is periodically changed in a direction intersecting the weld line according to the laser welding conditions.

The laser welding conditions include at least the welding speed V, i.e., the movement speed V of the laser head 500 along the weld line, the power of the second laser light LB2, and the spot diameter (beam diameter) of the second laser light LB2 irradiated onto the workpiece 900.

By configuring the laser welding method in this way, it is possible to perform the desired laser welding while reducing spatter even when the laser welding conditions are changed for a workpiece 900 made of a material that has a low light absorption rate for laser light in the near-infrared wavelength range, such as copper.

In addition, because the width of the weld bead 940 formed on the workpiece 900 can be changed, even when it is necessary to ensure a gap tolerance between plate materials, for example in butt welding, it is possible to prevent burn-through while ensuring the penetration depth.

As the welding speed V decreases or the power of the second laser light LB2 increases, it is preferable to change the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the first amplitude A1 becomes longer. In this way, the molten pool 910 formed on the workpiece 900 by the first laser light LB1 is enlarged, and the second laser light LB2 is irradiated into the inside of the molten pool 910, thereby suppressing the bumping of the molten pool 910 and the occurrence of spatters.

It is preferable to change the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the first frequency f1 increases as the welding speed V increases or the power of the second laser light LB2 decreases.

In this way, the molten pool 910 can be reliably formed in front of the irradiation position of the second laser beam LB2 while the first laser beam LB1 is scanning. Since the second laser beam LB2 is irradiated into the inside of the molten pool 910, the bumping of the molten pool 910 and the occurrence of spattering are suppressed.

As the welding speed V decreases or the power of the second laser light LB2 increases, it is preferable to change the irradiation position of the first laser light LB1 on the surface of the workpiece 900 so that the distance L or distance R between the irradiation position of the first laser light LB1 and the irradiation position of the second laser light LB2 in the direction along the weld line increases.

By increasing the distance L or the distance R, the molten pool 910 formed by the second laser beam LB2 can be prevented from exceeding the molten pool 910 formed by the first laser beam LB1. This suppresses the occurrence of bumping of the molten pool 910 during laser welding, and thus spattering.

The technology disclosed herein will be explained in more detail below using examples. Note that the examples shown below do not limit the technology disclosed herein in any way.

Figure 7 shows the appearance of the weld beads for Examples 1 and 2 and the comparative example.

Example 1
A copper plate was prepared as the workpiece 900. The first laser beam LB1 was irradiated along the welding direction of the workpiece 900, and the second laser beam LB2 was irradiated along the weld line behind the first laser beam LB1 at the same time as the first laser beam LB1. As a result, a linear weld bead was formed on the surface of the workpiece 900 (see the central photograph in FIG. 7).

The parameter values for laser welding were as follows. First, the wavelength λ1 of the first laser light LB1 was 450 nm, and the wavelength λ2 of the second laser light LB2 was 975 nm.

The welding speed V was set to 50 mm/sec. The power of the first laser light LB1 was set to 800 W, and the power of the second laser light LB2 was set to 1900 W. The spot diameter of the first laser light LB1 on the surface of the workpiece 900 was set to 400 μm, and the spot diameter of the second laser light LB2 was set to 40 μm.

When irradiating the first laser beam LB1, as shown in the center of FIG. 7, the first laser beam LB1 was scanned while periodically moving back and forth along the X direction. In this case, the first amplitude A1 was set to 400 μm, and the first frequency f1 was set to 200 Hz. In addition, the distance L between the irradiation position of the first laser beam LB1 and the irradiation position of the second laser beam LB2 along the welding direction was set to 50 μm.

In this case, as shown in the center of FIG. 7, the spot SP1 at one end of the first laser light LB1 along the X direction was irradiated onto the workpiece 900 so as to partially overlap with the spot SP1 at the other end.

Example 2
Except for setting the first amplitude A1 to 500 μm, the first laser beam LB1 and the second laser beam LB2 were irradiated onto the workpiece 900 using the same method and parameters as in Example 1. As a result, a linear weld bead 940 was formed on the surface of the workpiece 900 (see the photograph on the right side of FIG. 7 ).

In this case, as shown on the right side of FIG. 7, the spot SP1 at one end of the first laser light LB1 along the X direction is irradiated onto the workpiece 900 so as to be spaced apart in the X direction from the spot SP1 at the other end.

Comparative Example
The first laser beam LB1 and the second laser beam LB2 were simultaneously irradiated onto the workpiece 900 with the optical axes of the first laser beam LB1 and the second laser beam LB2 aligned with each other. As a result, a linear weld bead 940 was formed on the surface of the workpiece 900 (see the photograph on the left side of FIG. 7 ).

The wavelength λ1 of the first laser light LB1 and the wavelength λ2 of the second laser light LB2 were the same as in Examples 1 and 2, and the power of the first laser light LB1 and the power of the second laser light LB2 were also the same as in Examples 1 and 2. In addition, the spot diameter of the first laser light LB1 and the spot diameter of the second laser light LB2 on the surface of the workpiece 900 were also the same as in Examples 1 and 2, and the welding speed V was also the same as in Examples 1 and 2.

However, the first laser light LB1 was not scanned in the X direction. In other words, the first amplitude A1 described above was zero, and the distance L was also zero.

<Comparison of Results Between Examples 1 and 2 and Comparative Example>
7, in the comparative example, width W of weld bead 940 was 1121 μm. On the other hand, in example 1, width W of weld bead 940 was 1209 μm, and in example 2, width W of weld bead 940 was 1445 μm.

When laser welding was performed using the methods shown in Examples 1 and 2, the width W of the weld bead 940 was larger than when laser welding was performed using the method shown in the comparative example. This is presumably because the first laser beam LB1 was scanned in the X direction at the first amplitude A1. In other words, by scanning the first laser beam LB1 in the X direction, it is believed that the molten pool 910 formed by the first laser beam LB1 was made larger than in the comparative example, as intended. This is also supported by the fact that the width W of the weld bead 940 was larger in Example 2, in which the first amplitude A1 was larger than in Example 1.

After the weld bead 940 was formed, the surface of the workpiece 900, including the weld bead 940, was imaged with a camera. The obtained image was processed to estimate the number of spatter deposits on the surface of the workpiece 900.

When the number of sputter particles attached in the comparative example was normalized to 100, the number of sputter particles attached in the example 1 was 67, and the number of sputter particles attached in the example 1 was 62.

In other words, it was confirmed that in Examples 1 and 2 in which the technology disclosed herein was applied, spatter could be reduced more than in the comparative example. In other words, when laser welding is performed by irradiating the first laser light LB1 simultaneously with the second laser light LB2 and in front of the second laser light LB2, spatter can be reduced by periodically changing the irradiation position of the first laser light LB1 on the surface of the workpiece 900 in a direction intersecting the weld line.

Other Embodiments
As described above, the laser welding disclosed in this embodiment is one aspect of laser processing. Laser processing includes laser cutting for cutting the workpiece 900 in addition to laser welding. In addition, the laser processing is not limited to this. In the laser processing in this embodiment, a molten pool 910 is formed by irradiation with the first laser LB light 1 and the second laser light LB2, and the first laser LB light 1 and the second laser light LB2 are irradiated along a predetermined processing line.

In other words, in this specification, "welding" may be read as "processing." For example, laser welding conditions may be read as laser processing conditions. A laser welding method may be read as a laser processing method. A welding speed V may be read as a processing speed V. Also, a weld line may be read as a processing line.

As described above, when the first laser beam LB1 and the second laser beam LB2 are irradiated along a predetermined processing line, the position of the laser head 500 may be fixed, while the stage 800 provided with a stage movement mechanism (not shown) may be moved along the XY plane.

In view of this, it can be said that the laser processing apparatus 1000 disclosed herein only needs to have a movement mechanism that moves one of the workpiece 900 and the laser head 500 relative to the other. This movement mechanism includes the robot 600 and the stage movement mechanism described above.

In other words, the laser processing device 1000 disclosed herein has the following configuration:

The laser processing device 1000 includes at least a first laser oscillator 100 that emits a first laser beam LB1, a second laser oscillator 200 that emits a second laser beam LB2 having a longer wavelength than the first laser beam LB1, and a laser head 500 that receives the first laser beam LB1 and the second laser beam LB2 and emits them toward a workpiece 900. The laser processing device 1000 also includes a movement mechanism that moves one of the workpiece 900 and the laser head 500 relative to the other.

The laser head 500 has at least a housing 510, a first optical path changing mechanism 540, and a plurality of optical components arranged inside the housing 510. The plurality of optical components includes at least a first collimating lens 520, a second collimating lens 530, a beam combiner 550, a condensing lens 560, and a protective glass 570.

The housing 510 is provided with a first inlet 511 through which the first laser light LB1 is incident, a second inlet 512 through which the second laser light LB2 is incident, and an outlet 513 through which the first laser light LB1 and the second laser light LB2 are each emitted.

The first optical path changing mechanism 540 is disposed in the optical path of the first laser light LB1 between the first entrance 511 and the exit 513.

When laser processing the workpiece 900, the laser head 500 and the workpiece 900 are moved relative to each other by the above-mentioned movement mechanism, and the first laser light LB1 is irradiated simultaneously with the second laser light LB2 and in front of the second laser light LB2 in a direction along a predetermined processing line.

The first optical path changing mechanism 540 changes the optical path of the first laser light LB1 emitted from the emission port 513 according to the laser processing conditions.

In other words, the laser processing apparatus 1000 further includes a controller that controls the operation of at least the first optical path changing mechanism 540. The controller operates the first optical path changing mechanism 540 to change the optical path of the first laser light LB1 emitted from the emission port 513 in accordance with the laser processing conditions.

The controller may control the operation of the movement mechanism and the first optical path changing mechanism 540.

In this case, the first optical path changing mechanism 540 may change the optical path of the first laser light LB1 emitted from the emission port 513 in conjunction with the operation of the aforementioned moving mechanism in response to a control signal from the controller.

The laser processing device disclosed herein is useful in hybrid laser processing because it can reduce the occurrence of spatter even when the laser processing conditions are changed.

100 First laser oscillator 200 Second laser oscillator 300 First optical fiber 400 Second optical fiber 500 Laser head 510 Housing 511 First entrance 512 Second entrance 513 Exit 520 First collimating lens 530 Second collimating lens 540 First optical path changing mechanism 550 Beam combiner 560 Condenser lens 570 Protective glass 600 Robot 710 First laser controller 720 Second laser controller 730 Robot controller (controller)
800 Stage 900 Workpiece 1000 Laser processing device LB1 First laser beam LB2 Second laser beam

Claims (12)

a first laser oscillator that emits a first laser beam;
a second laser oscillator that emits a second laser beam having a longer wavelength than the first laser beam;
a laser head that receives the first laser light and the second laser light and emits them toward a workpiece;
a moving mechanism that moves one of the workpiece and the laser head relative to the other;
A laser processing apparatus comprising at least
the laser head has at least a housing, a first optical path changing mechanism, and a plurality of optical components disposed inside the housing;
The housing includes:
a first entrance through which the first laser light is incident;
a second entrance port through which the second laser light is incident;
an emission port through which the first laser light and the second laser light are respectively emitted,
the first optical path changing mechanism is disposed in an optical path of the first laser light between the first entrance and the exit,
When the workpiece is laser-machined, the moving mechanism moves one of the workpiece and the laser head relative to the other, and the first laser light is irradiated forward of the second laser light in a direction along a predetermined processing line, simultaneously with the second laser light;
the first optical path changing mechanism changes an optical path of the first laser light emitted from the emission port in accordance with laser processing conditions;
The laser processing conditions include at least a moving speed of the laser head along the processing line, a power of the second laser light, and a spot diameter of the second laser light irradiated onto the workpiece. 2. The laser processing apparatus according to claim 1,
A laser processing apparatus characterized in that the first optical path changing mechanism periodically changes the irradiation position of the first laser light on the surface of the workpiece in a direction intersecting the processing line in accordance with the laser processing conditions. 3. The laser processing apparatus according to claim 2,
When an amount of change in the irradiation position of the first laser light in a direction intersecting the processing line is defined as a first amplitude,
A laser processing apparatus characterized in that the first optical path changing mechanism changes the irradiation position of the first laser light on the surface of the workpiece so that the first amplitude becomes longer as the moving speed of the laser head decreases or the power of the second laser light increases. 3. The laser processing apparatus according to claim 2,
When the reciprocal of the period in which the irradiation position of the first laser light changes is defined as a first frequency,
A laser processing apparatus characterized in that the first optical path changing mechanism changes the irradiation position of the first laser light on the surface of the workpiece so that the first frequency becomes higher as the moving speed of the laser head increases or the power of the second laser light decreases. 3. The laser processing apparatus according to claim 2,
The laser processing apparatus is characterized in that the first optical path changing mechanism changes the irradiation position of the first laser light on the surface of the workpiece so that the distance between the irradiation position of the first laser light and the irradiation position of the second laser light becomes longer in the direction along the processing line as the moving speed of the laser head decreases or the power of the second laser light increases. 2. The laser processing apparatus according to claim 1,
a first optical fiber connected to the first entrance and configured to transmit the first laser light to the laser head;
a second optical fiber connected to the second entrance and transmitting the second laser light to the laser head. 2. The laser processing apparatus according to claim 1,
a controller that controls the operation of the moving mechanism and the first optical path changing mechanism,
The laser processing apparatus is characterized in that the first optical path changing mechanism changes the optical path of the first laser light emitted from the exit port in conjunction with the operation of the moving mechanism in response to a control signal from the controller. A laser processing method for laser processing a workpiece by irradiating the workpiece with a first laser beam and a second laser beam having a longer wavelength than the first laser beam, comprising:
The method includes at least a step of irradiating the first laser light and the second laser light simultaneously in a direction along a predetermined processing line on a surface of the workpiece, forward of the second laser light, to laser process the workpiece;
changing an irradiation position of the first laser light on a surface of the workpiece according to laser processing conditions;
The laser processing method characterized in that the laser processing conditions include at least a moving speed of the irradiation position of the second laser light along the processing line, a power of the second laser light, and a spot diameter of the second laser light irradiated to the workpiece. 9. The laser processing method according to claim 8,
A laser processing method comprising periodically changing an irradiation position of the first laser light on the surface of the workpiece in a direction intersecting the processing line according to the laser processing conditions. 10. The laser processing method according to claim 9,
When an amount of change in the irradiation position of the first laser light in a direction intersecting the processing line is defined as a first amplitude,
A laser processing method characterized in that the irradiation position of the first laser light on the surface of the workpiece is changed so that the first amplitude becomes longer as the moving speed of the irradiation position of the second laser light along the processing line becomes slower or the power of the second laser light becomes higher. 10. The laser processing method according to claim 9,
When the reciprocal of the period in which the irradiation position of the first laser light changes is defined as a first frequency,
A laser processing method comprising changing an irradiation position of the first laser light on a surface of the workpiece so that the first frequency becomes higher as the moving speed of the irradiation position of the second laser light along the processing line becomes higher or the power of the second laser light becomes lower. 10. The laser processing method according to claim 9,
A laser processing method characterized in that the irradiation position of the first laser light on the surface of the workpiece is changed so that the distance between the irradiation position of the first laser light and the irradiation position of the second laser light in a direction along the processing line becomes longer as the moving speed of the irradiation position of the second laser light along the processing line becomes slower or the power of the second laser light becomes higher.