JP2000042779A - Laser beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient melt depth even if the moving speed of a laser beam is fast, to prevent plural laser beams from splitting even if the position of a workpiece changes in the optical axis direction of the laser beam, and to hold the melt depth unchanged regardless of the moving direction of the laser beam. SOLUTION: The laser beam machining device 10 is provided with laser resonators 12A, 12B for generating laser beams A, B, a beam mixing means 14 for coinciding and mixing the optical axes Aa, Ba for the laser beams A, B generated from the resonators 12A, 12B, a beam irradiation means 16 for emitting to a workpiece 94 the laser beams A, B mixed by the beam mixing means 14, and focal position varying means 18, 20 capable of freely moving the focal points Af, Bf of the laser beams A, B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a laser processing apparatus for performing welding, joining, drilling, cutting, removing, modifying and the like using the energy of a plurality of laser beams.

[0002]

2. Description of the Related Art As a conventional laser processing technique, a technique using a single laser beam has been widely used. Also, a laser processing technique using a plurality of laser beams is disclosed in
No. 300087 discloses this.

[0003]

However, in the former laser processing technique, the higher the moving speed of the laser beam, the more unstable the keyhole becomes. As a result, the depth of the keyhole becomes shallow, and the amount of reflected light also increases. That is, when the moving speed of the laser beam is high, there is a problem that the melting depth becomes shallow.

In the latter laser processing technique, as shown in FIG. 9, the focal points 90f and 92f of laser beams 90 and 92 having different optical axes are radiated to one point 96 of a workpiece 94 in a concentrated manner. Therefore, when the position of the workpiece 94 fluctuates in the optical axis direction of the laser beams 90 and 92, the laser beams 90 and 92 do not converge at one point on the workpiece 94, so that there is a problem that sufficient processing cannot be performed. Was. Further, when the laser beams 90 and 92 are moved on the workpiece 94, there is another problem that the melting depth varies depending on the moving direction. This seems to be due to the directivity of the positional relationship between the laser beams 90 and 92.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser processing apparatus which achieves any of the following. . Even when the moving speed of the laser beam is high, a sufficient melting depth can be obtained. . Even if the position of the workpiece changes in the optical axis direction of the laser beam, the plurality of laser beams do not separate. . The melting depth does not change depending on the moving direction of the laser beam.

[0006]

According to a first aspect of the present invention, there is provided a laser processing apparatus comprising: a plurality of laser resonators for generating laser beams; and an optical axis coincident with the plurality of laser beams generated from the laser resonators. And a beam irradiating unit for irradiating the workpiece with the laser beam mixed by the beam mixing unit.

[0007] A plurality of laser beams are irradiated onto a workpiece while their optical axes are aligned. Therefore, no matter how the position of the workpiece changes, the plurality of laser beams are not separated. In addition, since the positional relationship between the plurality of laser beams on the workpiece is not directional, the melting depth does not change depending on the moving direction.

According to a second aspect of the present invention, there is provided a laser processing apparatus according to the first aspect, further comprising a focus position changing means capable of freely moving a focus position of the laser beam.

According to a third aspect of the present invention, in the laser processing apparatus according to the second aspect, the focal position changing means has a deformable mirror whose curvature of a mirror surface is changed by an electric signal. Since the deformable mirror changes the curvature of the mirror surface, the focal position can be changed without moving the optical component in the optical path length direction.

According to a fourth aspect of the present invention, in the laser processing apparatus according to the second aspect, the focal position varying means makes the focal positions of the plurality of laser beams different from each other. Since a plurality of focal points are formed on the optical axis, a deeper fusion depth can be obtained.

According to a fifth aspect of the present invention, in the laser processing apparatus according to the first aspect, the mirror provided with a return light reflecting film for reflecting return light of a laser beam generated from the laser resonator is provided. It is provided in. The return light of the laser beam does not return to the laser resonator because it is reflected by the mirror with the return light reflection film.

[0012]

FIG. 1 is a configuration diagram showing a first embodiment of a laser processing apparatus according to the present invention. Hereinafter, description will be made based on this drawing.

The laser processing apparatus 10 according to the present embodiment includes laser resonators 12A, 12A for generating laser beams A, B.
B, beam mixing means 14 for mixing the laser beams A and B generated from the laser resonators 12A and 12B with the optical axes Aa and Ba coincident with each other, and the laser beams A and B mixed by the beam mixing means 14. Beam irradiation means 16 for irradiating the workpiece 94 with the laser beam A, the focal points Af,
Focus position changing means 1 capable of freely moving Bf
8, 20.

The laser resonator 12A is a carbon dioxide laser (wavelength 10.6 [μm]), and the laser resonator 12B is a YAG laser.
Laser (wavelength 1.06 [μm]). Laser resonator 12
A and 12B respectively have a mirror 22 with a return light reflecting film.
A, 22B are provided. The mirrors with return light reflecting films 22A and 22B protect the laser resonators 12A and 12B by preventing return light of the laser beams A and B from entering the laser resonators 12A and 12B. A reflection mirror 24 is provided between the mirror 22A with the return light reflection film and the beam mixing means 14.

The beam mixing means 14 includes a dichroic mirror 141 for transmitting the laser beam A and reflecting the laser beam B, and a dichroic mirror 141.
And a dustproof housing 142 that accommodates Laser beam A
Is transmitted through the dichroic mirror 141 at an incident angle of 45 °, and the laser beam B is transmitted through the dichroic mirror 141 by 45 °.
By reflecting at an incident angle of °, each optical axis A
a and Ba match.

The beam irradiating means 16 comprises a concave mirror 161 and can be moved to a desired processing position by a moving mechanism (not shown).

The focus position changing means 18 is a deformable mirror 18
1 and the focus position changing means 20 is a deformable mirror 20
1,202. Deformable mirrors 181, 201, 2
Numeral 02 is provided with a piezo actuator (not shown) that deforms in accordance with a current value, and a metal reflective film (not shown) that continuously deforms from a concave surface to a convex surface by a force generated by the piezo actuator, thereby providing electricity. The curvature of the mirror surface changes according to the signal. Deformable mirror 18
By controlling the irregularities of 1,..., The spot diameter, focal position, focal depth, and the like at the focal point of the laser beams A and B can be arbitrarily set without moving the optical component in the optical path length direction. . Such deformable mirrors are
It is sold by EHL as "Adaptive Optics".

The focal position changing means 20 is provided between the mirror 22B with the return light reflecting film and the beam mixing means 14. The laser beam B transmitted through the return light reflecting film-equipped mirror 22B is reflected by the deformable mirror 201, reflected by the deformable mirror 202, and then proceeds to the beam mixing means 14. The laser beam A
The focal position of the laser beam B can be set arbitrarily with respect to the focal position.

The focus position changing means 18 is provided between the beam mixing means 14 and the beam irradiation means 16. The laser beam A,
It is possible to make the light collecting states of B coincide or differ. Further, a gap sensor (not shown) for detecting a displacement between the focal points Af, Bf and the workpiece 94, and a controller (not shown) for controlling unevenness of the deformable mirror 181 based on data of the displacement from the gap sensor. ), The positions of the focal points Af and Bf with respect to the workpiece 94 can be corrected.

Since the laser processing apparatus 10 has the focus position changing means 20 including two deformable mirrors 201 and 202, the laser beam B has a divergence angle significantly larger than the laser beam A, and the laser beams A and B Is suitable when the total output is 5 [kW] or less.

FIG. 2 shows a welding state of the workpiece 94 by the laser processing apparatus 10, and FIG.
[2] is a vertical sectional view taken along the line II-II in FIG. 2 [1].
Hereinafter, the operation of the laser processing apparatus 10 will be described with reference to FIGS.

The laser beams A and B are traveling on the workpiece 94 in the direction of arrow 26. A keyhole 941 is formed in a portion irradiated with the laser beams A and B, and a welding bead 9 is formed in a portion already irradiated with the laser beams A and B.
42 are formed.

The laser beams A and B are applied to the workpiece 94 with the optical axes Aa and Ba aligned. Therefore, even if the position of the workpiece 94 changes, the laser beams A and B do not separate. Further, since the positional relationship between the laser beams A and B on the workpiece 94 has no directionality, the melting depth does not change depending on the moving direction. Further, since the positions of the focal points Af and Bf of the laser beams A and B are different, two focal points Af and Bf are arranged on one optical axis Aa and Ba.
Is formed, so that a deeper melting depth is obtained. Therefore, a favorable welding state is maintained even during high-speed welding.
The positions of the focal points Af and Bf are not limited to the case where the focal point Af is shallow and the focal point Bf is deep as shown in the figure, but the focal point Af may be deep and the focal point Bf may be shallow, as in the example shown in FIG. Is also good.

FIG. 3 is a configuration diagram showing a second embodiment of the laser processing apparatus according to the present invention. Hereinafter, description will be made based on this drawing. However, the same parts as those in FIG.

The laser processing apparatus 30 according to the present embodiment includes laser resonators 12A, 12A for generating laser beams A, B.
B, beam mixing means 14 for mixing the laser beams A and B generated from the laser resonators 12A and 12B with the optical axes Aa and Ba coincident with each other, and the laser beams A and B mixed by the beam mixing means 14. Beam irradiation means 16 for irradiating the workpiece 94 with the laser beam A, the focal points Af,
Focus position changing means 2 capable of freely moving Bf
0, 32.

The focus position changing means 32 includes a deformable mirror 3
21 is provided between the mirror 22A with the return light reflection film and the beam mixing means 14. The laser beam A transmitted through the return light reflecting film-equipped mirror 22A is reflected by the deformable mirror 321, and then proceeds to the beam mixing means 14.
The focal point A of the laser beam A is changed by the deformable mirror 321.
The position of f can be set arbitrarily. Also, beam mixing means 1
A reflection mirror 34 is provided between 4 and the beam irradiation means 16.

Since the laser processing apparatus 30 has the focal position changing means 20 including two deformable mirrors 201 and 202, the laser beam B has a divergence angle significantly larger than that of the laser beam A, and the laser beams A and B Is suitable when the total output is 5 [kW] or more.

FIG. 4 is a configuration diagram showing a third embodiment of the laser processing apparatus according to the present invention. Hereinafter, description will be made based on this drawing. However, the same parts as those in FIGS. 1 and 3 are denoted by the same reference numerals, and redundant description will be omitted.

The laser processing apparatus 40 according to the present embodiment comprises laser resonators 12A, 12A for generating laser beams A, B.
B, beam mixing means 14 for mixing the laser beams A and B generated from the laser resonators 12A and 12B with the optical axes Aa and Ba coincident with each other, and the laser beams A and B mixed by the beam mixing means 14. Beam irradiation means 16 for irradiating the workpiece 94 with the laser beam A, the focal points Af,
Focus position changing means 3 capable of freely moving Bf
2, 42.

The focus position changing means 42 includes the deformable mirror 4
21 and is provided together with the reflecting mirror 44 between the mirror 22B with the return light reflecting film and the beam mixing means 14. The laser beam B transmitted through the return light reflecting film-equipped mirror 22B is reflected by the reflecting mirror 44, and then reflected by the deformable mirror 4B.
The light is reflected at 21 and subsequently proceeds to the beam mixing means 14. The position of the focal point Bf of the laser beam B can be arbitrarily set by the deformable mirror 421.

The laser processing device 40 includes a deformable mirror 32
1 variable focal position means 32 and deformable mirror 42
Since the focus position changing means 42 of 1 is used, it is suitable when the divergence angle of the laser beams A and B is relatively small and when the total output of the laser beams A and B is 5 [kW] or more.

FIG. 5 is a block diagram showing a fourth embodiment of the laser processing apparatus according to the present invention. Hereinafter, description will be made based on this drawing. However, the same parts as those in FIGS. 1 and 4 are denoted by the same reference numerals, and redundant description will be omitted.

The laser processing apparatus 50 according to the present embodiment comprises laser resonators 12A, 12A for generating laser beams A, B.
B, beam mixing means 14 for mixing the laser beams A and B generated from the laser resonators 12A and 12B with the optical axes Aa and Ba coincident with each other, and the laser beams A and B mixed by the beam mixing means 14. Beam irradiation means 16 for irradiating the workpiece 94 with the laser beam A, the focal points Af,
Focus position changing means 1 capable of freely moving Bf
8, 42.

The laser processing device 50 includes the deformable mirror 18
1 and a deformable mirror 321
Variable position mirror 32 and deformable mirror 421
This is suitable for the case where the divergence angles of the laser beams A and B are relatively small and the case where the total output of the laser beams A and B is 5 [kW] or less.

FIG. 6 is a block diagram showing a fifth embodiment of the laser processing apparatus according to the present invention. Hereinafter, description will be made based on this drawing. However, the same parts as those in FIGS. 1 and 4 are denoted by the same reference numerals, and redundant description will be omitted.

The laser processing apparatus 60 according to the present embodiment includes laser resonators 12A, 12A for generating laser beams A, B.
B, beam mixing means 14 for mixing the laser beams A and B generated from the laser resonators 12A and 12B with the optical axes Aa and Ba coincident with each other, and the laser beams A and B mixed by the beam mixing means 14. Beam irradiation means 16 for irradiating the workpiece 94 with the laser beam A, the focal points Af,
Focus position changing means 2 capable of freely moving Bf
0,62.

The focus position changing means 62 includes the deformable mirror 6
21 and 622, a mirror 22A with a return light reflecting film
And the beam mixing means 14. The laser beam A transmitted through the mirror with return light reflection film 22A is
After being reflected by the deformable mirror 621, the deformable mirror 622
, And then proceeds to the beam mixing means 14. The focal point A of the laser beam A is changed by the deformable mirrors 621 and 622.
The position of f can be set arbitrarily.

The laser processing device 50 includes the deformable mirror 20
1 and 202, and the focal position varying means 62 composed of deformable mirrors 621 and 622, so that the divergence angles of the laser beams A and B are both relatively large and that the laser beams A and B are relatively large. Total output of 5
[KW] or more.

FIG. 7 is a partial configuration diagram showing a sixth embodiment of the laser processing apparatus according to the present invention. Hereinafter, description will be made based on this drawing. However, the same parts as those in FIG.

The laser processing apparatus of this embodiment is characterized by the beam mixing means 74. The beam mixing means 74 detects the dichroic mirror 141 that transmits the laser beam A and reflects the laser beam B, the dustproof housing 142 that houses the dichroic mirror 141, and the laser beam B that has slightly transmitted through the dichroic mirror 141. And a photodetector 741.

The irradiation surface S1 of the laser beam B of the dichroic mirror 141 is provided with a coating for transmitting the laser beam A (carbon dioxide laser) and reflecting the laser beam B (YAG laser). The irradiation surface S2 of the dichroic mirror 141 with the laser beam A is provided with a coating for transmitting the laser beam A. However, since there is no coating that totally reflects 100% of the YAG laser, the laser beam B slightly transmits through the dichroic mirror 141. Therefore,
In the beam mixing means 74, the dichroic mirror 141
The deterioration or damage of the dichroic mirror 141 is detected by providing the photodetector 741 for detecting the laser beam B transmitted through the mirror. That is, if the laser beam B detected by the photodetector 741 is abnormal, it can be determined that the dichroic mirror 141 has been deteriorated or damaged.

FIG. 8 is a schematic diagram showing a focal position of a laser beam in the laser processing apparatus according to the present invention.
[1] is a first example, FIG. 8 [2] is a second example, FIG. 8 [3] is a third example, and FIG. 8 [4] is a fourth example. Hereinafter, description will be made based on this drawing. However, the same parts as those in FIG.

The focal points Af, Bf of the laser beams A, B are
2, the following positional relationship can be taken.
In the first example of FIG. 8A, the focal points Af and Bf are both on the processing surface 940. The second example of FIG.
Both f and Bf are outside the work surface 940. FIG.
In the third example of [3], one focus Af is on the processing surface 940, and the other focus Bf is on the processing surface 940. In the fourth example of FIG. 8D, one of the focal points Af is
Above, and the other focal point Bf is within the processing surface 940.

In the example shown in FIG. 2, both the focal points Af and Bf are within the processing surface 940. Although not shown, the focal points Af, Bf
Is in the work surface 940 and the other is in the work surface 940
It may be outside. In the drawing, the focal points Af,
The position of Bf may be reversed.

It is needless to say that the present invention is not limited to the above embodiment. For example, the laser beam is not limited to the carbon dioxide gas laser and the YAG laser, and the number of laser beams may be three or more. The focal position changing means may be constituted by a lens or the like.

[0046]

According to the laser processing apparatus of the first to fifth aspects, the beam mixing means for mixing the plurality of laser beams so that their optical axes coincide with each other is provided, so that the optical axes of the plurality of laser beams are provided. Can be applied to the workpiece. Therefore, it is possible to prevent a plurality of laser beams from being separated due to a change in the position of the workpiece. Also,
Since there is no directivity in the positional relationship between the laser beams, it is possible to prevent the melting depth from changing depending on the moving direction.

According to the laser processing apparatus of the second to fourth aspects, the desired melting depth can be obtained by providing the focal position changing means capable of freely moving the focal position of the laser beam. .

According to the laser processing apparatus of the third aspect,
Since the focal position varying means having the deformable mirror whose curvature of the mirror surface is changed by an electric signal is provided, the focal position can be changed without moving the optical component in the optical path length direction. Therefore, as compared with the case where the focal position is changed by a lens or the like, downsizing and high-speed response can be achieved.

According to the laser processing apparatus of the fourth aspect,
By making the focal positions of the plurality of laser beams different from each other by the focal position varying means, a deeper fusion depth can be obtained. Therefore, it is possible to suppress the melting depth from becoming shallow due to the high-speed movement of the laser beam.

According to the laser processing apparatus of the fifth aspect,
By providing the mirror with the return light reflection film for reflecting the return light of the laser beam in the laser resonator, damage to the laser resonator due to the return light can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a laser processing apparatus according to the present invention.

2 shows a welding state of a workpiece by the laser processing apparatus of FIG. 1, FIG. 2 [1] is a plan view, and FIG. 2 [2] is FIG.
FIG. 2 is a vertical sectional view taken along the line II-II in [1].

FIG. 3 is a configuration diagram showing a second embodiment of the laser processing apparatus according to the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the laser processing apparatus according to the present invention.

FIG. 5 is a configuration diagram showing a fourth embodiment of the laser processing apparatus according to the present invention.

FIG. 6 is a configuration diagram showing a fifth embodiment of the laser processing apparatus according to the present invention.

FIG. 7 is a partial configuration diagram showing a sixth embodiment of the laser processing apparatus according to the present invention.

8 is a schematic view showing a focal position of a laser beam in the laser processing apparatus according to the present invention, wherein FIG. 8 [1] is a first example, FIG. 8 [2] is a second example, and FIG. 8 [3] is Third example, FIG.
[4] is a fourth example.

FIG. 9 is an explanatory view showing a problem of the conventional laser processing apparatus.

[Explanation of symbols]

 10, 30, 40, 50, 60 Laser processing apparatus 12A, 12B Laser resonator 14, 70 Beam mixing means 16 Beam irradiation means 18, 20, 32, 42, 62 Focus position changing means 94 Workpieces A, B Laser beam Aa, Ba Optical axis of laser beam Af, Bf Focus of laser beam

Claims (5)

[Claims] 1. A plurality of laser resonators for generating a laser beam, a beam mixing means for mixing the plurality of laser beams generated from these laser resonators with their optical axes aligned, and a beam mixing means. A beam irradiation unit for irradiating the workpiece with the mixed laser beam. 2. The laser processing apparatus according to claim 1, further comprising a focus position changing unit that can freely move a focus position of the laser beam. 3. The laser processing apparatus according to claim 2, wherein said focal position changing means has a deformable mirror whose curvature of a mirror surface changes according to an electric signal. 4. The apparatus according to claim 1, wherein the focus position changing unit changes the focus positions of the plurality of laser beams.
The laser processing apparatus according to claim 2. 5. The laser processing apparatus according to claim 1, wherein a mirror with a return light reflecting film for reflecting return light of a laser beam generated from the laser resonator is provided in the laser resonator.