JP2001108869A - High output laser beam transmission method, its device, and laser beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of reflected light from an optical fiber 12 of high output laser beams 11. SOLUTION: In this method for transmitting high output laser beams 11 through the optical fiber 12, the high output laser beams 11 are made incident on and transmitted in the optical fiber 12 on the laser beam entrance end surface having the diameter R larger than the core diameter r to reduce the incident energy density of the high output laser beams 11, thereby reducing the influence of the reflected light of the high output laser beams 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-power laser light transmission method and apparatus for transmitting high-power laser light output from a laser oscillator through an optical fiber. In addition, the present invention relates to a laser processing device that causes a high-power laser beam output from a laser oscillator to enter an optical fiber and outputs the high-power laser beam transmitted by the optical fiber from the processing device as a laser beam.

[0002]

2. Description of the Related Art Laser light is highly directional and has high energy, so it is precisely welded, cut, drilled, and surface modified by condensing it into small points or lines to form a laser beam. It is used for processing. In recent years, various laser devices (laser oscillators, focusing optics, etc.) that oscillate laser light with high output (for example, 5KW to 10KW) have been developed, and high-power laser light has been used as a light source for laser processing devices, for example, laser welding devices. Is being used.

[0003] Since the laser beam has a very directivity and a large energy, it is possible to perform a highly efficient welding process by condensing the laser beam on a small point or line to form a laser beam. The high-power laser light output from the laser device is perpendicularly incident on an optical fiber, guided to a laser welding device, converted into a laser beam for welding, and irradiated to a workpiece.

[0004]

[Problems to be Solved by the Invention] For example, 5KW to 10KW
When the high-power laser light is vertically incident on the optical fiber to transmit the high-power laser light, the output of the reflected light reflected on the incident surface of the optical fiber has a magnitude that cannot be ignored. That is, when laser light is incident on the optical fiber, several percent of reflected light is generated. However, when laser light with an output of less than 3 KW is incident, the reflected light output is very small, so it can be ignored. There was almost no effect on peripheral equipment.

[0005] However, the reflected light of the high-power laser light has a high output of, for example, 400 W or more that can be welded, and the high-power reflected light reflected from the optical fiber is returned to the condensing optical system or the laser oscillator. Become. There is no problem when the reflected light is directly incident on the crystal of the laser oscillator (YAG crystal in the case of a YAG laser). However, when the reflected light is incident on a metal or resin supporting member supporting the YAG crystal, the supporting member is not affected. Was heated and the YAG crystal might be damaged starting from the support member. For this reason, the reflected light of the high-power laser light cannot be ignored.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a high-power laser light transmission method and apparatus capable of reducing the influence of reflected light of high-power laser light input to an optical fiber. Aim. Also,
It is an object of the present invention to provide a laser processing apparatus capable of reducing the influence of reflected light of high-power laser light input to an optical fiber on a laser oscillator side device.

[0007]

According to the present invention, there is provided a high-power laser light transmission method for transmitting high-power laser light through an optical fiber. The high power laser is incident on the optical fiber at the laser light incident end face and transmitted. Further, the high-power laser light transmission method of the present invention for achieving the above object is a high-power laser light transmission method for transmitting a high-power laser light through an optical fiber, wherein the high-power laser light is transmitted at an angle to a laser light incident end face. Light is incident on an optical fiber and transmitted. And the output of high power laser light is
It is characterized by 3KW or more.

In order to achieve the above object, a high-power laser light transmission device according to the present invention comprises a high-power laser light transmission device for transmitting high-power laser light through an optical fiber. In this case, a tapered end portion having a gradually larger diameter is provided, and a laser beam incident end surface having a diameter larger than the core diameter is provided. The tapered end is formed integrally with the core of the optical fiber. Further, the tapered end portion is provided by being fused to the core portion of the optical fiber. The optical fiber is characterized in that the incident end face of the optical fiber is coated with a non-reflective coating material. In addition, the output of the high-power laser light is 3KW or more.

In order to achieve the above object, a high-power laser light transmission device according to the present invention comprises a high-power laser light transmission device for transmitting a high-power laser light through an optical fiber, wherein the incident end face of the optical fiber is angled. It is characterized by. Further, the incident end face of the optical fiber is formed to be inclined. Further, the incident end face of the optical fiber is characterized by being formed to be inclined in a polygonal shape. Further, the incident end face of the optical fiber is characterized by being formed so as to be concave or convex. Further, the optical fiber is characterized in that the incident end of the optical fiber is supported at an angle. The optical fiber is characterized in that the incident end face of the optical fiber is coated with a non-reflective coating material. In addition, the output of the high-power laser light is 3KW or more.

In order to achieve the above object, a laser processing apparatus according to the present invention is arranged such that a high-power laser beam output from a laser oscillator is incident on an optical fiber, and the high-power laser beam transmitted by the optical fiber is transmitted to an optical system of the processing apparatus. type in,
In a laser processing apparatus that performs processing by irradiating a laser beam output from a processing apparatus onto a workpiece, a tapered end formed by gradually increasing the incident end of the optical fiber with respect to the core diameter is provided. The laser light incident end face also has a large diameter.

In order to achieve the above object, a laser processing apparatus according to the present invention is arranged such that a high-power laser beam output from a laser oscillator is incident on an optical fiber, and the high-power laser beam transmitted by the optical fiber is transmitted to an optical system of the processing apparatus. type in,
In a laser processing apparatus for performing processing by irradiating a workpiece with a laser beam output from a processing apparatus, an incident end face of an optical fiber is angled.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a laser processing apparatus provided with a high-power laser light transmission device according to an embodiment of the present invention. FIG. 1 shows a schematic configuration of a laser welding apparatus provided with a high-power laser light transmission device according to an embodiment of the present invention, and FIG. 2 shows a graph showing a relationship between an incident position and an output intensity. In the present embodiment, a laser welding apparatus has been described as an example of a laser processing apparatus. However, other apparatuses such as a laser cutting apparatus can be applied as the laser processing apparatus.

The laser welding apparatus will be described with reference to FIG. As shown in the figure, the laser welding device 1 includes a laser device 3 having a laser oscillator 2. The laser oscillator 2 is a YAG laser oscillator formed of a slab-shaped YAG crystal 4, an excitation semiconductor 5, an optical resonator total reflection mirror 6, and an optical resonator partially transmitting mirror 7. YA
Both ends of the G crystal 4 are supported and fixed to the main body 9 by support members (made of metal or resin) 8.

The YAG crystal 4 may have a rod shape, and the excitation semiconductor 5 may be an excitation lamp. The laser oscillator 2 outputs a continuous wave laser light or a pulse wave laser light at a high output (3 KW or more, for example, 5 to 10 KW). In the illustrated example, the laser oscillator 2 of the laser device 3 is one set, but a plurality of sets can be provided as necessary, and the laser oscillators that output the continuous wave laser light or the pulse wave laser light are individually provided. It may be.

The laser oscillator 2 is provided with a condenser lens system 10, and the high-power laser light 11 output from the laser oscillator 2 is condensed by the condenser lens system 10 and is incident on an optical fiber 12. A welding head 13 is connected to the optical fiber 12, and the high-power laser light 11 incident on the optical fiber 12 is transmitted by the optical fiber 12 and sent to the welding head 13, and is converted into a laser beam 14 via a condensing system (not shown) as a base material 15. Is irradiated. The laser welding apparatus 1 forms a penetration 16 in the base material 15 by irradiating the base material 15 with a laser beam 14 from the welding head 13 and performs welding.

As a high-power laser light transmission device, a tapered end portion 12a having a diameter gradually larger than a core portion 12b is provided at an incident end portion of the optical fiber 12, and a laser incident end surface having a diameter larger than the core diameter r. (Diameter R). The tapered end 12a is drawn and stretched to form the core 12b.
And are formed integrally.

Referring to FIG. 2, the state of the output of the optical fiber 12 having the tapered end portion 12a having a diameter gradually increased with respect to the core portion 12b with respect to the laser incident position will be described. FIG. 2 shows the results of measuring the output state of the laser light of P (W) when the laser incident position with respect to the laser incident end face is shifted by Δx in the horizontal direction and Δy in the vertical direction. As can be seen from the figure, even if the laser incident position is shifted with respect to the laser incident end face with the tapered end 12a, the laser light can be transmitted with a loss of about 20% at the maximum. For this reason, even if the optical fiber 12 having the tapered end portion 12a formed gradually larger in diameter with respect to the core portion 12b is applied to the transmission of the high-power laser beam 11 of the laser welding apparatus 1, there is no problem in the welding process. I understand.

A high-power laser beam 11 is applied to an optical fiber 12.
Incident on the optical fiber 12, several percent of reflected light is generated. However, since the laser incident end face of the optical fiber 12 is larger in diameter than the core diameter r, the incident energy density of the high-power laser light 11 can be reduced. . For this reason, as a high-power laser light transmission method, the high-power laser light 11 is incident on the optical fiber 12 at the laser incident end face having a diameter larger than the core diameter r and transmitted, so that the reflected light of the high-power laser light 11 is output. Can be reduced, and high-power laser light 1
The output of the reflected light of 1 is a slight output, and even if it is ignored, there is almost no effect on peripheral devices. Therefore, even if the reflected light reflected by the optical fiber 12 is returned to the condenser lens system 10 and the laser oscillator 2 side, the YA of the laser oscillator 2
The metal or resin support member 8 supporting the G crystal 4 is not heated, and the YAG crystal 4 is not likely to be damaged.

As shown in FIG. 3, a non-reflective coating material 17 is applied to the laser incident end face of the tapered end 12a of the optical fiber 12.
It is also possible to coat. By coating the non-reflective coating material 17, the reflected light is reduced, and the influence of the reflected light on peripheral devices is further reduced. When the anti-reflection coating material 17 is coated, the light resistance of the laser incident end face of the optical fiber 12 generally decreases. However, since the incident energy density of the high-power laser light 11 decreases, the light resistance decreases. Never.

Another embodiment of the optical fiber will be described with reference to FIGS. FIG. 4 shows a schematic configuration of an optical fiber according to another embodiment, and FIG. 5 shows a graph showing a transmission state of the optical fiber according to another embodiment.
The same members as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

As shown in FIG. 4, the input end of the optical fiber 21 is provided with a tapered end 21a having a diameter gradually larger than that of the core 21b. Diameter R). The tapered end 21a is formed separately from the core 21b of the optical fiber 21, and the tapered end 21a is fused to and integrated with the core 21b. The anti-reflection coating material 17 is coated on the laser incident end face of the tapered end 21a of the optical fiber 21. The anti-reflection coating material 17 does not necessarily have to be coated.

The state of the output power with respect to the input power P (W) of the optical fiber 21 provided by fusing the tapered end 21a having a gradually larger diameter to the core 21b will be described with reference to FIG. FIG. 5 shows the result of measurement of the output state when P (W) laser light is incident on the laser incident end face. As can be seen from the figure, even if the laser beam is incident with the tapered end 21a fused and provided, the laser beam can be transmitted with little loss. For this reason, the core
Even if the optical fiber 21 provided by fusing the tapered end portion 21a formed with a gradually larger diameter with respect to 21b is applied to the transmission of the high-power laser beam 11 of the laser welding apparatus 1, there is no problem in the welding process. I understand.

In the laser welding apparatus 1 provided with the high-power laser light transmission device having the above-described configuration, when the high-power laser light 11 is incident on the optical fiber 21, the incident energy density of the high-power laser light 11 is reduced similarly to the optical fiber 12. The output of the reflected light of the high-power laser beam 11 becomes small, and even if it is ignored, there is almost no effect on peripheral devices.

Therefore, the laser welding apparatus 1 described above
The light reflected by the optical fiber 21 is collected by the condenser lens system 10.
Or return to the laser oscillator 2 side,
The metal or resin supporting member 8 supporting the YAG crystal 4 is not heated, and the YAG crystal 4 is not likely to be damaged.

A laser processing apparatus provided with a high-power laser light transmission apparatus according to another embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a schematic configuration of a laser welding apparatus provided with a high-power laser light transmission device according to another embodiment of the present invention, FIG. 7 is a detailed state of an incident end face of an optical fiber, and FIG. 3 is a graph showing the relationship between the intensity of reflected light and the intensity of reflected light. Note that the same components as those of the laser welding apparatus shown in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

As shown in FIG. 6, a high-power laser beam 11 (with an output of 3 KW or more, for example, 5 KW to 10 KW) output from a laser oscillator 2 of a laser device 3 is condensed by a condensing lens system 10 and an optical fiber. 31. The high-power laser beam 11 incident on the optical fiber 31 is transmitted by the optical fiber 31 and sent to the welding head 13, and the laser beam 14 from the welding head 13 is irradiated on the base material 15 to melt the base material 15. Form and perform welding.

As shown in FIG. 7, as a high-power laser light transmission device, an incident end face 32 of an optical fiber 31 has an angle θ.
(Polishing). Is set in the range of ± 2.5 degrees to ± 8.0 degrees, preferably in the range of ± 2.0 degrees to ± 3.5 degrees. Incidentally, it is also possible to coat the incident end face 32 with a non-reflective coating material.

The angle θ of the incident end face 32 of the optical fiber 31
The reason why is set in the range of ± 2.5 degrees to ± 8.0 degrees will be described with reference to FIG. As shown in the figure, when the angle θ of the incident end face 32 is larger than ± 2.5 degrees, the reflected light intensity decreases, and when it exceeds ± 8.0 degrees, the reflected light intensity is kept low. Therefore, by setting the angle θ of the incident end face 32 of the optical fiber 31 in the range of ± 2.5 degrees to ± 8.0 degrees, the intensity of the reflected light of the high-power laser light 11 can be reduced.

In the laser welding apparatus 1 provided with the high-power laser light transmission device having the above-described configuration, when the high-power laser light 11 is incident on the optical fiber 31, the incident end face 32 is inclined at the angle θ. The reflected light of the light 11 is reflected in a direction different from the incident direction and the intensity of the reflected light is reduced, so that the light is not returned to the condenser lens system 10 or the laser oscillator 2 side.

Therefore, the laser welding apparatus 1 described above
As a high-power laser light transmission method, by injecting and transmitting the high-power laser light 11 at an angle to the incident end face of the optical fiber 31, the influence of the reflected light can be reduced. The metal or resin support member 8 supporting the crystal 4 is not heated, and the YAG crystal 4 is not likely to be damaged.

Referring to FIGS. 9 to 13, another embodiment of the optical fiber in which the high-power laser beam 11 is incident at an angle to the incident end face will be described.

The optical fiber 31 shown in FIG. 9 is an example in which an inclined outgoing end face 33 is formed on an output side in addition to an inclined incoming end face 32. In this case, since the direction of the laser beam on the output side changes, it is necessary to devise a lens system on the welding head 13 side. The optical fiber 35 shown in FIG.
This is an example in which the incident end face 36 is formed to be inclined in a polygonal shape. The optical fiber 38 shown in FIG.
Is an example formed in a concavely inclined manner. The optical fiber 41 shown in FIG. 12 is an example in which the incident end face 42 is formed to be convexly inclined. Optical fiber 44 shown in FIG.
Is an example in which the optical fiber 44 itself is tilted by a holder 46 having a vertical incident end face 45 and holding the optical fiber 44 so that the high-power laser beam 11 is tilted and incident. In each case, the inclination angle θ (the angle of the tangent in the case of unevenness) is set in the range of ± 2.5 degrees to ± 8.0 degrees.
Further, the outgoing end face 33 and the incoming end faces 36, 39, 42, 4
5 can also be coated with a non-reflective coating material.

The optical fibers 31, 35, 38,
When the high-power laser light 11 is incident on the laser beams 42 and 44, the intensity of the reflected light of the high-power laser light 11 decreases, and the influence of the reflected light can be reduced.

[0034]

The method for transmitting high-power laser light according to the present invention comprises:
In the high-power laser light transmission method of transmitting high-power laser light through an optical fiber, a high-power laser is incident on the optical fiber at the laser light incident end face with a diameter larger than the core diameter and transmitted. The incident energy density can be reduced. As a result, the output of the reflected light of the high-power laser light can be reduced, and the influence of the reflected light of the high-power laser light can be reduced.

In the high-power laser light transmission method according to the present invention, in the high-power laser light transmission method for transmitting a high-power laser light through an optical fiber, the high-power laser light is transmitted to the optical fiber at an angle with respect to the laser light incident end face. Since the incident light is transmitted, the reflected light of the high-power laser light is reflected in a direction different from the incident direction, and the reflected light intensity decreases. As a result, the output of the reflected light of the high-power laser light can be reduced, and the influence of the reflected light of the high-power laser light can be reduced.

The high-power laser light transmission device according to the present invention is a high-power laser light transmission device for transmitting high-power laser light through an optical fiber, wherein the incident end of the optical fiber has a taper end formed to have a diameter gradually larger than the core diameter. Part,
Since the laser light incident end face has a diameter larger than the core diameter, the incident energy density of the high-power laser light can be reduced. As a result, the output of the reflected light of the high-power laser light can be reduced, and the influence of the reflected light of the high-power laser light can be reduced.

Further, the configuration of the high-power laser light transmission device of the present invention is such that the incident end face of the optical fiber is angled in the high-power laser light transmission device for transmitting the high-power laser light through an optical fiber. Is reflected in a direction different from the incident direction, and the reflected light intensity decreases. As a result, the output of the reflected light of the high-power laser light can be reduced, and the influence of the reflected light of the high-power laser light can be reduced.

Further, the laser processing apparatus of the present invention is arranged such that a high-power laser beam output from a laser oscillator is incident on an optical fiber, and the high-power laser light transmitted by the optical fiber is input to an optical system of the processing apparatus. In the laser processing apparatus that performs processing by irradiating the workpiece with the laser beam output from the optical fiber, a tapered end formed by gradually increasing the incident end of the optical fiber with respect to the core diameter is provided, and is larger than the core diameter. Since the laser light incident end face of the diameter
The incident energy density of the high-power laser light can be reduced. As a result, the output of the reflected light of the high-output laser light can be reduced, and the influence of the reflected light of the high-output laser light on the device on the laser oscillator side can be reduced.

Further, the laser processing apparatus of the present invention is arranged such that a high-power laser beam output from a laser oscillator is incident on an optical fiber, and the high-power laser beam transmitted by the optical fiber is input to an optical system of the processing apparatus. In the laser processing equipment that irradiates the workpiece with the laser beam output from the laser, the angle of the incident end face of the optical fiber is changed, so that the reflected light of the high-power laser light is reflected in a direction different from the incident direction. The reflected light intensity is reduced. As a result, the output of the reflected light of the high-output laser light can be reduced, and the influence of the reflected light of the high-output laser light on the device on the laser oscillator side can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a laser welding device including a high-power laser light transmission device according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between an incident position and an output intensity.

FIG. 3 is a schematic configuration diagram of an optical fiber according to another embodiment.

FIG. 4 is a schematic configuration diagram of an optical fiber according to another embodiment.

FIG. 5 is a graph showing a transmission state of an optical fiber according to another embodiment.

FIG. 6 is a schematic configuration diagram of a laser welding device including a high-output laser light transmission device according to another embodiment.

FIG. 7 is an explanatory view showing a detailed situation of an incident end face of an optical fiber.

FIG. 8 is a graph showing the relationship between the angle of the incident end face and the intensity of reflected light.

FIG. 9 is a schematic configuration diagram of an optical fiber according to another embodiment.

FIG. 10 is a schematic configuration diagram of an optical fiber according to another embodiment.

FIG. 11 is a schematic configuration diagram of an optical fiber according to another embodiment.

FIG. 12 is a schematic configuration diagram of an optical fiber according to another embodiment.

FIG. 13 is a schematic configuration diagram of an optical fiber according to another embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 laser welding device 2 laser oscillator 3 laser device 4 YAG crystal 5 semiconductor 6 optical resonator total reflection mirror 7 optical resonator partial reflection mirror 8 support member 9 main body 10 condensing lens system 11 high-power laser beam 12, 21, 31, 31, 35, 38, 41, 44 Optical fiber 12a, 21a Tapered end 12b, 21b Core 13 Welding head 14 Laser beam 15 Base material 16 Penetration 17 Non-reflective coating material 32, 36, 39, 42, 45 Incident end face 33 Exit end face

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Takashi Ishide 2-1-1, Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Yoshio Hashimoto 2-1-1, Shinama, Arai-machi, Takasago City, Hyogo Prefecture No. 1 Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor, Takeshi Satake 4-chome, Ikejiri, Itami-shi, Hyogo Pref. F term (reference) 2H037 AA04 BA06 CA07 CA09 CA10 4E068 CA02 CE08

Claims (15)

[Claims] 1. A high-power laser light transmission method for transmitting high-power laser light through an optical fiber, wherein a high-power laser is incident on the optical fiber at a laser light incident end face having a diameter larger than a core diameter and transmitted. High power laser light transmission method. 2. A high-power laser light transmission method for transmitting high-power laser light through an optical fiber, wherein the high-power laser light is incident on the optical fiber at an angle to the laser light incident end face and transmitted. Output laser light transmission method. 3. The high-power laser light transmission method according to claim 1, wherein the output of the high-power laser light is 3 KW or more. 4. A high-power laser light transmission device for transmitting high-power laser light through an optical fiber, wherein a tapered end is formed in which an incident end of the optical fiber is formed to have a diameter gradually larger than a core diameter, and is larger than the core diameter. A high-power laser light transmission device having a laser light incident end face having a diameter. 5. The high-power laser light transmission device according to claim 4, wherein the tapered end is formed integrally with the core of the optical fiber. 6. The high-power laser light transmission device according to claim 4, wherein the tapered end is provided by fusing to a core of the optical fiber. 7. A high-power laser light transmission device for transmitting high-power laser light through an optical fiber, wherein an angle of an incident end face of the optical fiber is set. 8. The high-power laser light transmission device according to claim 7, wherein an incident end face of the optical fiber is formed in an inclined shape. 9. The high-power laser light transmission device according to claim 8, wherein an incident end face of the optical fiber is formed to be inclined in a polygonal shape. 10. The high-power laser light transmission device according to claim 8, wherein an incident end face of the optical fiber is formed to be inclined in a concave or convex shape. 11. The high-power laser light transmission device according to claim 7, wherein an incident end of the optical fiber is supported at an angle. 12. The high-power laser light transmission device according to claim 4, wherein the optical fiber has an incident end face coated with a non-reflective coating material. 13. The high power laser light transmission device according to claim 4, wherein the output of the high power laser light is 3 KW or more. 14. A high-power laser beam output from a laser oscillator is incident on an optical fiber, the high-power laser beam transmitted by the optical fiber is input to an optical system of a processing apparatus, and a laser beam output from the processing apparatus is received. In a laser processing apparatus that performs processing by irradiating a workpiece, the input end of the optical fiber is provided with a tapered end formed to be gradually larger in diameter with respect to the core diameter, and a laser light incident end face having a diameter larger than the core diameter is provided. A laser processing apparatus, characterized in that: 15. A high-power laser beam output from a laser oscillator is incident on an optical fiber, the high-power laser beam transmitted by the optical fiber is input to an optical system of a processing device, and a laser beam output from the processing device is received. What is claimed is: 1. A laser processing apparatus for irradiating a workpiece to perform processing, wherein an incident end face of an optical fiber is angled.