JP2006263771A - Laser beam machining device and laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of a welding defect by charging energy having a profile uniform in a depth direction to a keyhole by sub-beams while performing keyhole welding. <P>SOLUTION: The main beam Bm which is outputted from a laser light source 210 and is adjusted in a diameter by a zoom mechanism 240 and the sub-beams Bs1 to Bs3 of a plurality of different wavelengths which are outputted from laser light source (a plurality of semiconductor lasers etc.) 220 and are adjusted in diameters by beam-condensing characteristic adjusting sections (zoom mechanisms, lens replacement mechanisms, optical fiber position conversion mechanisms, etc.) 250 are superposed on dichroic mirrors 261 of a beam superposition section 260, and are emitted on a workpiece 100. At this time, focus positions F1, F2, F3, F0 of the beams Bs1 to Bs3, Bm varying in the wavelengths vary with respect to the thickness direction of the workpiece 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method suitable for use in performing heat processing such as welding, cutting, and surface treatment using a laser beam.

  Laser welding is a method for welding a metal base material to be welded. In laser welding, a laser beam is condensed using an optical means such as a lens to increase the energy density. Then, the base material is melted by this high energy laser beam for welding. The melting ability of the laser beam varies depending on the type of the beam, the beam spot area (laser beam diameter) when being focused and irradiated onto the processed surface of the base material, and the like.

  In performing laser welding, as shown in FIG. 5, a laser beam 130 condensed by optical means or the like is irradiated to the groove of the workpiece 100 (base materials 110, 120) to be welded. To do. By continuously irradiating the laser beam 130 in the direction of the arrow at a constant speed, the groove portions of the base materials 110 and 120 are instantaneously melted and evaporated. Then, a consistent keyhole 150 from the surface to the inside of the base materials 110 and 120 is obtained. The keyhole 150 is surrounded by a molten metal 140. The molten metal 140 flows in a direction away from the keyhole 150 by convection (the direction opposite to the arrow), and is cooled and solidified by the heat conduction of the base materials 110 and 120. By doing so, the base material 110 and the base material 120 are welded.

  Thus, in the process of forming the keyhole 150 by increasing the energy by condensing the laser beam 130 and performing welding by moving the laser beam 130, the tip portion 153, the intermediate portion 152 of the keyhole 150, In the opening 151, a bubble-like cavity called porosity (or blowhole) 160 is left behind, resulting in a welding defect (see, for example, Non-Patent Document 1).

  This is because the hole formed as the keyhole 150 is maintained as the laser beam 130 moves, but the atmosphere gas in the keyhole 150 is easily trapped in the vicinity of the tip 153, and the laser beam 130 moves. Accordingly, the shape of the intermediate portion 152 of the keyhole 150 is not a straight shape but a constricted shape. When the intermediate portion 152 has a constricted shape, the atmospheric gas in the keyhole 150 is easily involved. Further, when the laser beam 130 moves, the molten metal 140 convects and covers the opening 151 so as to close it.

  Thus, when the shape of the keyhole 150 becomes unstable during laser welding, a bubble-like cavity called porosity 160 is left behind in the metal after laser welding, which is a weld defect. It becomes a factor of.

  When laser processing such as laser welding as described above is performed, improvement in oscillation efficiency (conversion efficiency from electricity to light), processing efficiency, and processing quality is desired.

Currently, lasers widely used in the industry include a CO ₂ laser and a YAG laser, but the application of a YAG laser capable of transmitting an optical fiber is expanding for welding.
However, the YAG laser has a problem that the oscillation efficiency is low (for example, the oscillation efficiency is about 3% in the lamp excitation method and the oscillation efficiency is about 15% in the semiconductor laser excitation method), and the running cost becomes high.

On the other hand, as lasers with high oscillation efficiency, there are semiconductor lasers (LD: laser diodes), fiber lasers, and the like. Outputs of these semiconductor lasers with high oscillation efficiency can be used for metal welding and cutting in recent years. The output has been increased to the level.
In addition, the laser beam output from the semiconductor laser has a shorter wavelength compared to the laser beam output from other types of lasers, so the absorption characteristics (ie, the material absorption rate) to metals are good. It is.

However, the semiconductor laser has a problem that the light condensing property is not good and cannot be narrowed down to a small spot particularly in a high output machine due to oscillation characteristics.

  Therefore, processing is performed by superimposing a laser beam of a semiconductor laser with high oscillation efficiency and good material absorption characteristics but poor condensing performance and a laser beam of another laser with good condensing performance (YAG laser, fiber laser, etc.). As a result, the inventor of the present application developed and applied for a patent for a laser welding technique that improves oscillation efficiency and material absorbability as a whole, and improves the light condensing property and suppresses the occurrence of welding defects such as porosity. Application 2003-160301).

  Here, the outline | summary of the technique disclosed by Japanese Patent Application No. 2003-160301 which the inventor of this application invented and has applied already is demonstrated.

  In the technology disclosed in Japanese Patent Application No. 2003-160301, in the thickness direction of a workpiece, energy of a more appropriate distribution is applied from a laser beam, and laser processing such as welding, cutting, and heat treatment is performed with higher quality. is there.

  FIG. 6 is a diagram showing the concept of laser processing in the embodiment disclosed in Japanese Patent Application No. 2003-160301. As shown in the figure, this laser processing uses a main beam Bm and a plurality of sub beams Bs1, Bs2, and Bs3 to weld a base material 110 and a base material 120 that are workpieces.

The main beam Bm is a high-intensity, high-condensing (that is, high energy density) laser beam output from a fiber laser, YAG laser, or CO ₂ laser. The main beam Bm is a laser beam having a diameter of 0.01 to 2.0 mm, and is irradiated so as to focus on the workpiece 100 at a predetermined position. The converging angle of the main beam Bm is θ0.

  The sub-beams Bs1, Bs2, and Bs3 are laser beams with a high material absorption rate (generally having a short wavelength) output from the semiconductor laser. The sub beams Bs1, Bs2, and Bs3 have respective condensing angles θ1, θ2, and θ3 larger than the condensing angle θ0 of the main beam Bm. The sub beams Bs 1, Bs 2, and Bs 3 are different from each other in positions where the focal points (hereinafter referred to as “focus positions”) F 1, F 2, and F 3 are in the thickness direction of the workpiece 100. More specifically, in the order of θ1> θ2> θ3, the focal position F1 of the sub beam Bs1 is near the surface of the workpiece 100, and the focal position F2 of the sub beam Bs2 is the middle in the thickness direction of the workpiece 100. The focal position F3 of the sub beam Bs3 is set near the lower end in the thickness direction of the workpiece 100 in the vicinity of the portion.

When welding is performed, the sub-beams Bs1, Bs2, and Bs3 are set in consideration of multiple reflections and energy attenuation in the keyhole 150, so that they are equal or arbitrary in the depth direction of the keyhole 150 ( Energy having a distribution such as strengthening a specific portion can be input by the sub beams Bs1, Bs2, and Bs3.
As a result, for example, as shown in FIG. 7, the sub-beams Bs1, Bs2, and Bs3 can impart energy with a more uniform distribution in the depth direction to the workpiece 100 than in the past.

  In this way, when the workpiece 100 is irradiated with the multifocal beam composed of the main beam Bm and the sub-beams Bs1, Bs2, and Bs3, the workpiece 100 is instantaneously melted and melted by the high energy main beam Bm. Evaporate. And the keyhole 150 consistent from the processing surface of the workpiece 100 to the inside is formed, and deep penetration is obtained.

  When the workpiece 100 is melted, the molten metal around the keyhole 150 is convected, and a part of the molten metal tries to block the keyhole 150. At this time, since the sub-beams Bs1, Bs2, and Bs3 are irradiated to the keyhole 150, some molten metal that attempts to close the keyhole 150 is irradiated with the sub-beams Bs1, Bs2, and Bs3 and flows. Promotes or evaporates. For this reason, in the keyhole 150, the shape is stably maintained at each depth from the opening portion 151 to the tip portion 153, and the situation of the entrainment of atmospheric gas is eliminated, thereby preventing the occurrence of porosity. it can.

Japanese Patent Application Laid-Open No. 2004-154813 Katayama Seiji, Seto Naoki, Mizutani Masami, Matsunoro Akira, "Elucidation of Laser Welding Phenomenon", Proceedings of the 52nd Laser Processing Society, Laser Processing Society, p32-39

  In already filed Japanese Patent Application No. 2003-160301, a main beam Bm and a plurality of sub-beams Bs1, Bs2, and Bs3 are combined by a combining member, and the combined beam is condensed by a condensing member to the workpiece 100. A simple configuration of the irradiating optical system is shown.

As a result of further earnest research, the inventor of the present application has come up with a laser processing apparatus and a laser processing method including an optical system that is more realistic and easy to configure.
Accordingly, an object of the present invention is to provide a laser processing apparatus and a laser processing method including an optical system that is more realistic and easy to configure.

The configuration of the present invention for solving the above problems is as follows.
One or more first laser light sources for outputting a first laser beam of one wavelength or for outputting a first laser beam of a plurality of different wavelengths;
A second laser light source that outputs a plurality of second laser beams having a wavelength shorter than that of the first laser beam and different from each other;
A beam superimposing unit that superimposes the first laser beam and the second laser beam;
The lens includes a lens having chromatic aberration for condensing the first laser beam and the second laser beam superimposed by the beam superimposing unit and irradiating the laser beam toward the workpiece, and the thickness of the workpiece due to the chromatic aberration of the lens. It is characterized by comprising a beam condensing characteristic adjusting unit such as a zoom mechanism, a lens replacement mechanism, or an optical fiber position changing mechanism for making the focal position of each laser beam different with respect to the direction.

The configuration of the present invention is as follows.
One or more first laser light sources for outputting a first laser beam;
A second laser light source that outputs a plurality of second laser beams having a wavelength shorter than that of the first laser beam and different from each other;
A beam condensing characteristic adjusting unit such as a first zoom mechanism, a lens replacement mechanism, or an optical fiber position changing mechanism for adjusting the diameter of the first laser beam output from the first laser light source;
A beam focusing characteristic adjusting unit such as a second zoom mechanism, a lens replacement mechanism, or an optical fiber position changing mechanism for adjusting the diameter of the second laser beam output from the second laser light source;
A beam superimposing unit that superimposes the first laser beam transmitted through the first zoom mechanism and the second laser beam transmitted through the second zoom mechanism;
The lens comprises a lens having chromatic aberration for condensing the first laser beam and the second laser beam superimposed by the beam superimposing unit and irradiating the processed laser beam toward the workpiece. And a condensing unit that makes the focal position of each laser beam different in the thickness direction of the workpiece by adjusting the mechanism or the like.

The configuration of the present invention is as follows.
The first laser light source can each adjust the intensity of one or more first laser beams,
The first laser light source is constituted by a laser having better condensing characteristics than a semiconductor laser, such as a YAG laser or a fiber laser.
The second laser light source can adjust the intensity of each of the plurality of second laser beams,
The second laser light source is constituted by a semiconductor laser.

The configuration of the present invention is as follows.
The beam superimposing unit is constituted by a dichroic mirror that reflects one of the first laser beam and the second laser beam and transmits the other,
The beam superimposing unit is
A conical lens that circulates the second laser beam into a donut-shaped beam and sends it to the condensing unit;
A total reflection mirror that reflects the first laser beam and sends it to the condensing unit through the central portion of the annular beam;
The beam superimposing unit is
A plurality of reflecting mirrors for branching the second laser beam into a plurality of beams and sending them to the condensing unit;
A total reflection mirror that reflects the first laser beam and sends the first laser beam to the condensing unit through a space between the branched second laser beams is characterized.

In the present invention, the wavelength of the first laser beam or the plurality of laser beams and the plurality of second laser beams are different from each other. The focal position of each laser beam is different.
As a result, while having a simple optical structure, keyhole welding is performed with the first laser beam, and energy having a predetermined profile is injected with the second laser beam in the depth direction of the keyhole by the sub beam. It is possible to prevent the occurrence of weld defects such as porosity.

Furthermore, in the present invention, the diameters of the first laser beam and the second laser beam can be controlled by a beam condensing characteristic adjusting unit (such as a zoom mechanism, a lens replacement mechanism, or an optical fiber position changing mechanism). It is possible to easily adjust the depth and the energy distribution input to the keyhole.
Further, by making it possible to adjust the intensity of the second laser beam, it is possible to easily adjust the energy distribution put into the keyhole.
As a result, the occurrence of weld defects such as porosity can be more reliably prevented.

  Hereinafter, embodiments of the present invention will be described in detail based on examples.

  FIG. 1 shows a laser processing apparatus 200 according to Embodiment 1 of the present invention. The laser processing apparatus 200 is an apparatus that performs laser welding while forming a keyhole 150 by irradiating the workpiece 100 with a laser beam.

The laser processing apparatus 200 includes a first laser light source 210, a second laser light source 220, and an optical mechanism 230 as main members.
When performing laser welding, the optical mechanism 230 and the workpiece 100 can move relative to each other along the weld line of the workpiece 100. Since this relative movement mechanism is a well-known one that has been used conventionally, the description thereof is omitted here.

The first laser light source 210 is composed of a laser having better condensing characteristics than a semiconductor laser such as a YAG laser or a fiber laser. The laser light source 210 outputs a main beam Bm having high brightness and high light condensing performance (that is, high energy density) and a wavelength λ ₀ of about 1.0 μm. The main beam Bm is propagated to the optical mechanism 230 via the optical fiber 281.

  The second laser light source 220 includes a plurality of semiconductor lasers 221 to 223 (illustrated in the case of three in this embodiment), control circuits 224 to 226 for driving the semiconductor lasers, a total reflection mirror 227, and a dichroic. Mirrors (dichroic mirrors) 228 and 229 are used.

The semiconductor laser 221 is driven by the control circuit 224 to output a sub-beam Bs1 that is a laser beam having a wavelength λ1 of 808 nm. At this time, the intensity (kW) of the sub beam Bs1 can be adjusted by adjusting the drive current by the control circuit 224.
The semiconductor laser 222 is driven by the control circuit 225 to output a sub beam Bs2 that is a laser beam having a wavelength λ2 of 940 nm. At this time, the intensity (kW) of the secondary beam Bs2 can be adjusted by adjusting the drive current by the control circuit 225.
The semiconductor laser 223 is driven by the control circuit 226 to output a sub beam Bs3 that is a laser beam having a wavelength λ3 of 980 nm. At this time, the intensity (kW) of the sub beam Bs3 can be adjusted by adjusting the drive current by the control circuit 226.

  The sub-beams Bs1, Bs2, and Bs3 output from the semiconductor lasers 221 to 223 are superimposed and output in a coaxial state in which the optical axes coincide with each other by the total reflection mirror 227 and the dichroic mirrors 228 and 229. The superimposed sub beams Bs1, Bs2, and Bs3 are propagated to the optical mechanism 230 via the optical fiber 282.

  The sub-beams Bs1, Bs2, and Bs3 output from the semiconductor lasers 221 to 223 have wavelengths λ1, λ2, and λ3 of 808 nm, 940 nm, and 980 nm, respectively, which are more than about 1.0 μm of the wavelength λ0 of the main beam Bm. It is getting shorter. For this reason, the sub-beams Bs1, Bs2, and Bs3 have a higher material absorption rate than the main beam Bm.

The optical mechanism 230 includes zoom mechanism units (beam condensing characteristic adjusting units) 240 and 250, a beam superimposing unit 260, and a condensing unit 270 as main members.
The actual lens system provided in each part 240, 250, 270 of the optical mechanism 230 has a more complicated lens configuration than that shown in FIG. 1, but here the lens system is easy to understand. Is schematically illustrated.

In the zoom mechanism 240, a predetermined one of the lens systems 241 can move along the optical axis direction (α direction) to perform a zoom operation. The main beam Bm output from the laser light source 210 and propagated through the optical fiber 281 is transmitted through the lens system 241 of the zoom mechanism 240 and then sent to the beam superimposing unit 260. At this time, if the lens system 241 performs a zoom operation, that is, if a required one of the lens systems 241 moves in the α direction, the diameter and the aperture angle of the main beam Bm can be adjusted.
A zoom movement mechanism for zooming the lens system 241 is not shown.

In the zoom mechanism unit 250, a predetermined one of the lens systems 251 can move along the optical axis direction (β direction) to perform a zoom operation. The sub beams Bs 1, Bs 2, and Bs 3 output from the laser light source 220 and propagated through the optical fiber 282 are transmitted to the beam superimposing unit 260 after passing through the lens system 251 of the zoom mechanism unit 250. At this time, when the lens system 251 performs a zoom operation, that is, when a required one of the lens systems 251 moves in the β direction, the diameters and aperture angles of the sub beams Bs1, Bs2, and Bs3 can be adjusted.
A zoom movement mechanism for zooming the lens system 251 is not shown.

The beam superimposing unit 260 is configured with a dichroic mirror 261 as a main member. The dichroic mirror 261 is disposed obliquely with an inclination of 45 ° with respect to the optical axis direction (α direction) of the zoom mechanism 240 and the optical axis direction (β direction) of the zoom mechanism 250. Moreover, as shown in FIG. 2, the dichroic mirror 261 has transmission / reflection characteristics such that, for example, light having a wavelength of λ ₀ is reflected but light having wavelengths of λ ₁ to λ ₃ is transmitted. In addition, it is desirable to adopt one having a sharp transition change in transmission / reflection characteristics.

Therefore, the main beam Bm having a wavelength of λ ₀ transmitted along the α direction is reflected by the dichroic mirror 261, the propagation direction is changed by 45 °, and is propagated toward the condensing unit 270. On the other hand, the sub-beams Bs1, Bs2, and Bs3 having wavelengths λ ₁ , λ ₂ , and λ ₃ transmitted along the β direction are transmitted through the dichroic mirror 261 and propagated toward the condensing unit 270.
Eventually, due to the transmission / reflection function of the dichroic mirror 261, the main beam Bm and the sub beams Bs1, Bs2, and Bs3 are superimposed and propagated to the condensing unit 270 in a state where the optical axes coincide with each other.

  In the example of FIG. 1, the main beam Bm and the sub-beams Bs1, Bs2, and Bs3 are superimposed in a coaxial state. The optical axes of the main beam Bm and the sub beams Bs1, Bs2, and Bs3 after being superposed can be shifted (in this case, the optical axis is shifted, but the optical axis of the main beam Bm and the sub beams Bs1, Bs2, and Bs3). The optical axis of the

The condensing unit 270 has a condensing lens 271. The condensing lens 271 condenses the main beam Bm and the sub beams Bs1, Bs2, and Bs3 transmitted from the beam superimposing unit 260 and irradiates the workpiece 100 with the condensing lens 271. The condenser lens 271 is configured by appropriately combining a spherical concave lens, a spherical convex lens, an aspheric concave lens, an aspheric convex lens, and the like.
Here, a lens having a large chromatic aberration is positively employed as the lens used for the condenser lens 271.

The main beam Bm and the sub beams Bs1, Bs2, and Bs3 are irradiated toward the workpiece 100 after passing through the condenser lens 271, but the focal positions of the beams are different due to the influence of chromatic aberration of the condenser lens 271. .
That means
The focal position of the sub beam Bs1 having the wavelength λ1 of 808 nm is F1,
The focal position of the sub-beam Bs2 whose wavelength λ2 is 940 nm is F2,
The focal position of the sub beam Bs3 having the wavelength λ3 of 980 nm is F3,
When the focal position of the main beam Bs0 having a wavelength λ0 of about 1.0 μm is F0,
With respect to the thickness direction of the workpiece 100, the workpieces 100 are arranged in the order of the focal positions F 1, F 2, F 3, and F 0 from the surface side to the back in the thickness direction.

  In this way, when the workpiece 100 is irradiated with the multifocal beam composed of the main beam Bm and the sub beams Bs1, Bs2, and Bs3, the main beam Bm having high brightness and high condensing property (that is, high energy density). The workpiece 100 is instantaneously melted and evaporated. And the keyhole 150 consistent from the processing surface of the workpiece 100 to the inside is formed, and deep penetration is obtained.

  At this time, the intensity (kW) of the main beam Bsm output from the laser light source 210 is adjusted, or the zoom amount in the lens system 241 of the zoom mechanism 240 is controlled to adjust the diameter and aperture angle of the main beam Bm. By doing so, the system and depth of the keyhole 150 can be adjusted.

  A part of the molten metal that is irradiated with the sub-beams Bs1, Bs2, and Bs3 with good material absorptance (short wavelength) output from the semiconductor lasers 221 to 223 to fill the keyhole 150 is Evaporates efficiently and promotes flow. For this reason, in the keyhole 150, the shape is stably maintained at each depth from the opening portion to the tip portion, and the situation of the entrainment of atmospheric gas is eliminated. As a result, the generation of porosity can be prevented.

  When welding is performed, the sub-beams Bs1, Bs2, and Bs3 are set in consideration of multiple reflections and energy attenuation in the keyhole 150, so that they are equal or arbitrary in the depth direction of the keyhole 150 ( Energy having a distribution such as strengthening a specific portion can be input by the sub beams Bs1, Bs2, and Bs3.

  Specifically, the control circuits 224 to 226 of the laser light source 220 adjust the intensities (kW) of the sub beams Bs 1, Bs 2 and Bs 3 output from the semiconductor lasers 221 to 223, or the lens system 251 of the zoom mechanism 250. By controlling the zoom amount and adjusting the diameters and aperture angles of the sub-beams Bs1, Bs2, and Bs3, the irradiation positions and irradiation energy of the sub-beams Bs1, Bs2, and Bs3 in the keyhole 150 can be set. Thus, energy having a uniform or arbitrary distribution (intensifying a specific portion, etc.) in the depth direction of the keyhole 150 can be input by the sub beams Bs1, Bs2, and Bs3. That is, the distribution state of energy input to the keyhole 150 by the sub beams Bs1, Bs2, and Bs3 can be arbitrarily and easily adjusted.

As described above, in the laser processing apparatus 200 according to the first embodiment, the chromatic aberration of the condensing lens 271 of the condensing unit 270 is positively used, so that the thickness direction of the workpiece 100 is increased from the surface side. It is possible to align the beam focal positions in the order of the focal positions F1, F2, F3, and F0 toward the back in the thickness direction.
Therefore, the condensing lens 271 does not need to be specially devised to shift the beam focal position, and the focal position is shifted using chromatic aberration inherent in the lens. The optical structure of 270 may have a very simple configuration.

Further, in the first embodiment, since the beam superimposing unit 260 is configured by the dichroic mirror 261, the structure of the optical system of the beam superimposing unit 260 can be simplified, and the laser processing apparatus 200 as a whole can be reduced in size. Can do. Note that the axes can be shifted and superimposed by shifting the positions of the optical fibers 281 and 282.
As the beam condensing characteristic adjusting unit, a zoom mechanism, a lens replacement mechanism, an optical fiber position conversion mechanism, or the like can be used.

  FIG. 3 shows a laser processing apparatus 200A according to Embodiment 2 of the present invention. This laser processing apparatus 200A differs from the laser processing apparatus 200 according to the first embodiment in the structure of the beam superimposing portion 260A, and the other parts are the same as those in the first embodiment. For this reason, the description will be focused on the beam superimposing unit 260A.

  The beam superimposing portion 260A of the laser processing apparatus 200A according to the second embodiment includes conical lenses 262 and 263 and a total reflection mirror 264.

The conical lens 262 turns the sub-beams Bs1, Bs2, and Bs3 sent from the zoom mechanism 250 into a zonal beam that diffuses in a conical shape, and the conical lens 263 turns the sub-beams Bs1, Bs2, and Bs3 into parallel rings. A banded beam is sent to the condensing unit 270.
On the other hand, the total reflection mirror 264 is disposed at the center (portion where the sub beam does not exist) of the zonal beam that is brought into a parallel state by the conical lens 263, and receives the main beam Bm sent from the zoom mechanism 240. Reflecting and changing the propagation direction by 45 °, the main beam Bm is sent to the condensing unit 270.

With such a beam superimposing unit 260A, the main beam Bm and the sub beams Bs1, Bs2, and Bs3 can be superimposed and propagated to the condensing unit 270 in a state where the optical axes coincide with each other.
Note that the main beam Bm and the sub beams Bs1, Bs2, and Bs3 can be superimposed with the optical axis being shifted by shifting the position of the total reflection mirror 264 or by shifting the position of the optical fiber.

  FIG. 4 shows a laser processing apparatus 200B according to Embodiment 3 of the present invention. This laser processing apparatus 200B is different from the laser processing apparatus 200 according to the first embodiment in the structure of the beam superimposing portion 260B, and the other parts are the same as those in the first embodiment. For this reason, the description will be focused on the beam superimposing unit 260B.

  The beam superimposing unit 260B of the laser processing apparatus 200B according to the third embodiment includes total reflection mirrors 265, 266, and 267.

  Total reflection mirror 265 reflects and extracts a part of sub-beams Bs1, Bs2, and Bs3 sent from zoom mechanism 250. The total reflection mirror 266 reflects the sub-beams Bs1, Bs2, and Bs3 extracted by the total reflection mirror 265 and sends them to the condensing unit 270A.

  The total reflection mirror 267 is arranged at a portion where the sub beam does not exist because a part of the sub beams Bs1, Bs2, and Bs3 are extracted by the total reflection mirror 265, and the main beam Bm sent from the zoom mechanism 240 is received. Reflecting and changing the propagation direction by 45 °, the main beam Bm is sent to the condensing unit 270.

With such a beam superimposing unit 260A, the main beam Bm and the sub beams Bs1, Bs2, and Bs3 can be superimposed and propagated to the condensing unit 270 in a state where the optical axes coincide with each other.
Note that the main beam Bm and the sub beams Bs1, Bs2, and Bs3 can be superposed with their optical axes shifted by shifting the position of the total reflection mirror 267 or shifting the position of the optical fiber.

  In each of the above embodiments, the laser processing apparatus has been described as an apparatus used for laser welding. However, various kinds of thermal processing such as laser cutting and laser surface treatment can be performed using the laser processing apparatus of each of the above embodiments. Needless to say, you can.

The block diagram which shows the laser processing apparatus which concerns on Example 1 of this invention. FIG. 3 is a characteristic diagram showing transmission characteristics of a dichroic mirror used in Example 1. The block diagram which shows the laser processing apparatus which concerns on Example 2 of this invention. The block diagram which shows the laser processing apparatus which concerns on Example 3 of this invention. Explanatory drawing which shows keyhole welding. The conceptual diagram which shows the laser processing method which has already applied for. The conceptual diagram which shows the laser processing method which has already applied for.

Explanation of symbols

200, 200A, 200B Laser processing apparatus 210, 220 Laser light source 230 Optical mechanism 240, 250 Zoom mechanism 260, 260A, 260B Beam superimposing unit 270 Condensing unit

Claims (9)

A first laser light source that outputs a first laser beam;
A second laser light source that outputs a plurality of second laser beams having a wavelength shorter than that of the first laser beam and different from each other;
A beam superimposing unit that superimposes the first laser beam and the second laser beam;
Each of the lasers includes a lens having chromatic aberration for condensing the first laser beam and the second laser beam superimposed by the beam superimposing unit and irradiating the laser beam toward the workpiece, with respect to the thickness direction of the workpiece. A laser processing apparatus comprising a condensing unit that makes the focal position of a beam different. A first laser light source that outputs a first laser beam;
A second laser light source that outputs a plurality of second laser beams having a wavelength shorter than that of the first laser beam and different from each other;
A first beam focusing characteristic adjusting unit that adjusts a diameter of the first laser beam output from the first laser light source;
A second beam focusing characteristic adjusting unit that adjusts the diameter of the second laser beam output from the second laser light source;
A beam superimposing unit that superimposes the first laser beam transmitted through the first beam condensing characteristic adjusting unit and the second laser beam transmitted through the second beam condensing characteristic adjusting unit;
The lens comprises a lens having chromatic aberration for condensing the first laser beam and the second laser beam superimposed by the beam superimposing unit and irradiating the laser beam toward the workpiece, and adjusting the chromatic aberration and the beam condensing characteristic of the lens. And a condensing unit that makes the focal position of each laser beam different in the thickness direction of the workpiece. In claim 1 or claim 2,
The laser processing apparatus characterized in that the first and second laser light sources can respectively adjust the intensities of a plurality of laser beams. In any one of Claims 1 to 3,
The laser processing apparatus, wherein the first laser light source is composed of a laser having a better light condensing property than a semiconductor laser such as a YAG laser or a fiber laser. In any one of Claims 1 to 3,
The laser processing apparatus, wherein the second laser light source is constituted by a semiconductor laser. In any one of Claims 1 to 5,
The laser beam processing unit is constituted by a dichroic mirror that reflects one of the first laser beam and the second laser beam and transmits the other. In any one of Claims 1 to 5,
The beam superimposing unit is
A conical lens that circulates the second laser beam and sends it to the condensing unit;
A laser processing apparatus comprising: a total reflection mirror that reflects the first laser beam and sends the first laser beam to the condensing unit through a central portion of the zonal beam. In any one of Claims 1 to 5,
The beam superimposing unit is
A plurality of reflecting mirrors for branching the second laser beam into a plurality of beams and sending them to the condensing unit;
A laser processing apparatus comprising: a total reflection mirror that reflects the first laser beam and sends the first laser beam to the condensing unit through a space between the branched second laser beams. A first laser light source that outputs a first laser beam;
A second laser light source that outputs a plurality of second laser beams having a wavelength shorter than that of the first laser beam and different from each other;
A beam superimposing unit that superimposes the first laser beam and the second laser beam;
Each of the lasers includes a lens having chromatic aberration for condensing the first laser beam and the second laser beam superimposed by the beam superimposing unit and irradiating the laser beam toward the workpiece, with respect to the thickness direction of the workpiece. A laser processing method, characterized in that laser processing is performed by a laser processing apparatus including a condensing unit that makes the focal position of a beam different.

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