JP2023112732A - Laser machining device - Google Patents

Abstract

To enhance the machining quality and machining speed of work-piece.SOLUTION: A laser machining head 20 emits a first laser beam L1 of short wavelength, and a second laser beam L2 of long wavelength. A dichroic mirror 26 overlaps the first laser beam L1 and the second laser beam L2. An fθ lens 27 condenses the first laser beam L1 and the second laser beam L2 overlapped by the dichroic mirror 26 toward work-piece W. A first adjusting mechanism 24 adjusts an incident position of the first laser beam L1 to the dichroic mirror 26.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laser processing apparatus.

Patent Document 1 discloses an optical system that guides two lasers with a long wavelength and a short wavelength to a coaxial optical path and superimposes them, and converges the output beams of the two lasers superimposed on the coaxial optical path on a work (workpiece). A laser processing optical system is disclosed that includes a focusing lens that emits light.

JP 2005-324254 A

By the way, short-wavelength laser light has a high laser absorption rate for workpieces made of high reflectance materials such as copper and aluminum, but the maximum output of the laser light is low and the processing speed is low.

On the other hand, a long-wavelength laser beam has a higher maximum laser beam output than a short-wavelength laser beam, but has a lower laser absorptance with respect to a workpiece made of a highly reflective material. Therefore, it is difficult to make the penetration depth of the workpiece constant with a long-wavelength laser beam, and there is a possibility that the machining quality may deteriorate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to improve the machining quality and machining speed of workpieces.

A first invention is a laser processing apparatus that emits a laser beam to process a workpiece, comprising: a first laser oscillator that oscillates a first laser beam; and a second laser beam that has a longer wavelength than the first laser beam. and a laser processing head that emits the first laser beam and the second laser beam incident from the first laser oscillator and the second laser oscillator to the work. , the laser processing head passes through a first collimating lens for collimating the first laser beam, a second collimating lens for collimating the second laser beam, and the first collimating lens and the second collimating lens a first optical member for superimposing the first laser beam and the second laser beam; and condensing the first laser beam and the second laser beam superimposed by the first optical member toward the workpiece. a second optical member; and a first adjustment mechanism that adjusts the incident position of the first laser beam with respect to the first optical member and relatively changes the emission position of the first laser beam with respect to the second laser beam. characterized by having

In the first invention, the laser processing head emits a short-wavelength first laser beam and a long-wavelength second laser beam. The first laser beam and the second laser beam are superimposed by the first optical member. The first laser beam and the second laser beam superimposed by the first optical member are focused toward the workpiece by the second optical member. The first adjustment mechanism adjusts the incident position of the first laser beam with respect to the first optical member.

Thus, by adjusting the incident position of the first laser beam with respect to the first optical member and relatively changing the emission position of the first laser beam with respect to the second laser beam, the machining quality and machining speed of the workpiece can be improved. can be enhanced.

Specifically, the short-wavelength first laser light (for example, blue laser light of 600 nm or less) has a high laser absorption rate with respect to a workpiece made of a highly reflective material such as copper, but the maximum output of the laser light is low. On the other hand, the long-wavelength second laser beam (for example, infrared laser beam of 800 nm or longer) has a low laser absorptance with respect to a workpiece made of a highly reflective material, but has a high maximum laser beam output.

Therefore, for example, the workpiece is preheated by emitting the first laser beam ahead of the surface of the workpiece, and the second laser beam is emitted to the preheated portion of the workpiece, so that the second laser beam is absorbed by the workpiece. easier to be Thereby, the processing quality and processing speed of the workpiece can be improved.

In addition, by emitting the first laser beam behind the second laser beam, it is possible to clean the processing surface of the workpiece processed by the second laser beam. For example, the slag can be removed by emitting the first laser beam to the weld bead solidified after welding with the second laser beam. In addition, by emitting the first laser beam to the cut surface laser-cut by the second laser beam, the cut surface can be cleaned.

In a second invention, in the first invention, the incident position of the second laser beam with respect to the first optical member is adjusted to relatively change the emission position of the second laser beam with respect to the first laser beam. It is characterized by comprising a second adjustment mechanism for adjusting the

In the second invention, the second adjustment mechanism adjusts the incident position of the second laser beam with respect to the first optical member.

In this way, by making it possible to adjust the incident position of the second laser beam with respect to the first optical member, it is possible to widen the adjustment range of the emission position of the second laser beam with respect to the first laser beam.

According to a third invention, in the first or second invention, a detection unit for detecting data indicating a molten state at a processing position of the workpiece, and based on the data detected by the detection unit, the laser processing head, the and a control section for controlling the operation of at least one of the first laser oscillator and the second laser oscillator.

In the third invention, the detector detects the data indicating the molten state at the processing position of the workpiece. Then, based on the data detected by the detector, the emission position, emission timing, and the like of the laser beam can be controlled.

In a fourth aspect based on the third aspect, the detection unit includes a first detection unit that detects data indicating a melting state at a processing position of the workpiece corresponding to the first laser beam, and the first laser beam By oscillating the oscillator and stopping the second laser oscillator, the first laser beam is emitted from the laser processing head, and the first laser beam reflected by the work is detected by the first detection unit. The amount of scattered light is detected, and the control unit causes the second laser oscillator to oscillate when the amount of scattered light detected by the first detection unit is lower than a predetermined threshold, thereby controlling the laser processing head. The second laser beam is emitted from the second laser beam to the machining position of the workpiece.

In the fourth invention, after roughening the surface of the work in advance with the short-wavelength first laser light, the melting of the work is detected by the first detection unit based on the light quantity of the scattered light of the first laser light. , and finish machining the workpiece with the long-wavelength second laser beam, it is possible to improve the machining quality and machining speed of the workpiece.

In a fifth aspect based on the third aspect, the detection section includes a second detection section for detecting data indicating a melting state at a processing position of the workpiece corresponding to the second laser beam, and the first laser beam By oscillating the oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head, and the second laser beam reflected by the work is detected by the second detection unit. The amount of scattered light of light is detected, and when the amount of scattered light detected by the second detection unit is lower than a predetermined threshold, the control unit reduces the output of the second laser light stepwise or The operation of the second laser oscillator is controlled so as to gradually increase.

In the fifth invention, after the second laser beam having a long wavelength is emitted at a low output, it is determined that the workpiece has melted based on the amount of scattered light of the second laser beam detected by the second detection unit, By increasing the output of the second laser beam and processing the work, the processing quality and processing speed of the work can be increased.

In a sixth aspect based on the third aspect, the detection section includes a second detection section for detecting data indicating a melting state of the workpiece at the processing position corresponding to the second laser beam, and the first laser beam By oscillating the oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head, and the second laser beam reflected by the work is detected by the second detection unit. The amount of scattered light of light is detected, and when the amount of scattered light detected by the second detection unit is higher than a predetermined threshold, the first laser beam is emitted to the processing position of the workpiece. The operation of the laser processing head is controlled so as to emit a

In the sixth invention, after the long-wavelength second laser beam is emitted to the workpiece, it is detected by the second detection unit that the workpiece is not sufficiently melted based on the amount of scattered light of the second laser beam. It is possible to accelerate the melting of the workpiece by making a determination and emitting the short-wavelength first laser beam to the machining position of the workpiece.

In a seventh aspect based on the third aspect, the detection section includes a second detection section for detecting data indicating a melting state at a processing position of the workpiece corresponding to the second laser beam, and the first laser beam By oscillating the oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head, and the second laser beam reflected by the work is detected by the second detection unit. The amount of scattered light of light is detected, and when the amount of scattered light detected by the second detection unit is higher than a predetermined threshold, the control unit reduces the output of the first laser light stepwise or The operation of the first laser oscillator is controlled so as to gradually increase.

In the seventh invention, after the long-wavelength second laser beam is emitted to the workpiece, it is detected by the second detection unit that the workpiece is not sufficiently melted based on the amount of scattered light of the second laser beam. By further increasing the output of the short-wavelength first laser beam, it is possible to sufficiently preheat the workpiece and promote the melting of the workpiece.

In an eighth aspect based on the third aspect, the detection section includes a second detection section for detecting data indicating a melting state at a processing position of the workpiece corresponding to the second laser beam, and the first laser beam By oscillating the oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head, and the second laser beam reflected by the work is detected by the second detection unit. The amount of scattered light of light is detected, and the control unit stops outputting the second laser light when the amount of scattered light detected by the second detection unit is higher than a predetermined upper limit. It is characterized in that the operation of the second laser oscillator is controlled as follows.

In the eighth invention, it is possible to prevent the laser processing head from being damaged by the scattered light of the high-output second laser beam reflected by the workpiece being irradiated onto the laser processing head.

A ninth invention is characterized in that, in any one of the third to eighth inventions, the detection section is composed of a photodiode.

In the ninth aspect of the present invention, by configuring the detection section with a photodiode, it becomes easy to detect the light quantity of the scattered light of the laser beam, and the molten state of the workpiece can be confirmed with high accuracy.

According to the present invention, it is possible to improve the machining quality and machining speed of the workpiece.

It is a side view which shows schematic structure of the laser processing apparatus which concerns on this Embodiment 1. FIG. It is a graph chart which shows the relationship between the wavelength of a laser beam, and a reflectance. It is a top view which shows the state which radiate|emitted the 1st laser beam to the laser starting position. It is a top view which shows the state which radiate|emitted the 2nd laser beam to the laser starting position. FIG. 4 is a plan view showing a state during laser processing of a work; FIG. 10 is a side view showing a schematic configuration of a laser processing apparatus according to Embodiment 2; It is a graph chart which shows the relationship between the scattered light intensity|strength of a 2nd laser beam, and elapsed time.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the following description of preferred embodiments is essentially merely an example, and is not intended to limit the present invention, its applications, or its uses.

<<Embodiment 1>>
As shown in FIG. 1, the laser processing apparatus 1 includes a first laser oscillator 11, a second laser oscillator 12, a first transmission fiber 15, a second transmission fiber 16, a laser processing head 20, and a robot 2. , and a control unit 5 .

The first laser oscillator 11 outputs a first laser beam L1 based on a command from the control section 5 . The first laser beam L1 is a short wavelength laser beam. The short-wavelength first laser light L1 is blue laser light or green laser light with a wavelength of 600 nm or less (for example, 266 nm to 600 nm).

The first laser oscillator 11 and the laser processing head 20 are connected by a first transmission fiber 15 . The first laser beam L1 is transmitted from the first laser oscillator 11 to the laser processing head 20 via the first transmission fiber 15 .

The second laser oscillator 12 outputs the second laser light L2 based on the command from the control section 5 . The second laser beam L2 is a long-wavelength laser beam having a longer wavelength than the first laser beam L1. The long-wavelength second laser light L2 is infrared laser light with a wavelength of 800 nm or more (for example, about 800 nm to 16000 nm).

The second laser oscillator 12 and laser processing head 20 are connected by a second transmission fiber 16 . The second laser beam L2 is transmitted from the second laser oscillator 12 to the laser processing head 20 via the second transmission fiber 16 .

The laser processing head 20 emits the first laser beam L<b>1 and the second laser beam L<b>2 incident from the first transmission fiber 15 and the second transmission fiber 16 to the work W. As shown in FIG.

The laser processing head 20 includes a first collimating lens 21, a second collimating lens 22, a first mirror 23, a first adjusting mechanism 24, a second adjusting mechanism 25, and a dichroic mirror 26 (first optical member). , an fθ lens 27 (second optical member), and a first detector 28 .

The first collimator lens 21 collimates the first laser beam L1 emitted from the emission end of the first transmission fiber 15 . The second collimator lens 22 collimates the second laser beam L2 emitted from the emission end of the second transmission fiber 16 . The first mirror 23 reflects the first laser beam L<b>1 collimated by the first collimating lens 21 and guides it to the first adjusting mechanism 24 .

The first adjustment mechanism 24 is composed of a two-axis MEMS (Micro Electro Mechanical Systems) mirror. The first adjustment mechanism 24 further reflects the first laser beam L<b>1 reflected by the first mirror 23 and guides it to the dichroic mirror 26 . The first adjustment mechanism 24 changes the incident position of the first laser beam L1 with respect to the dichroic mirror 26 by changing the angle of the mirror. Note that the first adjustment mechanism 24 may be configured using a biaxial galvanometer (galvanomirror).

The second adjustment mechanism 25 is composed of a two-axis MEMS mirror. The second adjustment mechanism 25 reflects the second laser beam L2 collimated by the second collimator lens 22 and guides it to the dichroic mirror 26 . The second adjustment mechanism 25 changes the incident position of the second laser beam L2 on the dichroic mirror 26 by changing the angle of the mirror. The second adjustment mechanism 25 may be configured using a two-axis galvanometer.

The dichroic mirror 26 transmits the second laser beam L2 and reflects the first laser beam L1. The dichroic mirror 26 superimposes the first laser beam L<b>1 and the second laser beam L<b>2 and guides them to the fθ lens 27 .

The f.theta. Condensed so that The first laser beam L1 and the second laser beam L2 condensed by the f.theta.

Here, the incident positions of the first laser beam L1 and the second laser beam L2 with respect to the fθ lens 27 are moved by changing the angles of the first adjustment mechanism 24 and the second adjustment mechanism 25, respectively. Thereby, the emission positions of the first laser beam L1 and the second laser beam L2 with respect to the workpiece W can be relatively changed by the first adjustment mechanism 24 and the second adjustment mechanism 25 .

Here, by moving the first collimator lens 21 and the second collimator lens 22 in the optical axis direction, the beam diameters of the first laser beam L1 and the second laser beam L2 are changed to be enlarged or reduced, respectively. be able to.

The first detection unit 28 is composed of, for example, a photodiode. The first detection unit 28 detects data indicating the melting state of the workpiece W at the processing position. Here, the data indicating the molten state is the amount of scattered light of the first laser beam L1 reflected by the workpiece W. As shown in FIG.

A first filter 29 is arranged between the first detector 28 and the workpiece W. As shown in FIG. The first filter 29 shields the scattered light of the second laser beam L2 reflected by the workpiece W, while allowing the scattered light of the first laser beam L1 to pass through.

The first detector 28 detects the amount of scattered light of the first laser beam L1 that has passed through the first filter 29 . The detection result of the first detector 28 is sent to the controller 5 .

The control unit 5 determines that the workpiece W has been sufficiently preheated by the first laser beam L1 when the light amount of the scattered light of the first laser beam L1 is smaller than a predetermined threshold value.

Specifically, the light amount of the scattered light of the first laser beam L1 changes according to the molten state of the surface of the work W. As shown in FIG. For example, when the surface of the work W is not sufficiently preheated by the first laser beam L1 and the melt amount of the work W is small, the amount of scattered light of the first laser beam L1 increases. On the other hand, when the surface of the work W is sufficiently preheated by the first laser beam L1 and the melt amount of the work W is large, the light quantity of the scattered light of the first laser beam L1 becomes small.

The robot 2 has a robot arm 3 . A laser processing head 20 is attached to the tip of the robot arm 3 . The robot arm 3 has multiple joints 4 .

The robot 2 changes the position of the laser processing head 20 with respect to the workpiece W by moving the laser processing head 20 along a predetermined processing direction based on a command from the control unit 5 . As a result, the positions of the first laser beam L1 and the second laser beam L2 with respect to the workpiece W are moved to perform laser processing.

The controller 5 is connected to the first laser oscillator 11 , the second laser oscillator 12 , the laser processing head 20 and the robot 2 . The control unit 5 controls operations of the first laser oscillator 11 , the second laser oscillator 12 , the laser processing head 20 and the robot 2 .

In addition to the moving speed of the laser processing head 20, the control unit 5 controls the output start and stop of the first laser beam L1 and the second laser beam L2, the output intensity of the first laser beam L1 and the second laser beam L2, and the like. It also has the function to In addition, although the control part 5 has one structure here, you may comprise more than one.

The work W has a first member W1 and a second member W2. The first member W1 and the second member W2 are plate-shaped. The first member W1 is superimposed on the upper surface of the second member W2.

The workpiece W is composed of a high reflectance material with a low laser absorption rate. Specifically, as shown in FIG. 2, the reflectance of the laser beam varies depending on the material of the workpiece W. As shown in FIG. For example, when infrared laser light having a long wavelength of 800 nm or more is used as a reference, copper (Cu), aluminum (Al), gold (Au), and silver (Ag) are laser beams compared to iron (Fe). It can be seen that the reflectance (%) of the wavelength of light is high, in other words, it is a high reflectance material with low laser absorptance. On the other hand, iron (Fe) has a relatively low reflectance (%) of the wavelength of the laser light, in other words, it is a low reflectance material with a high laser absorptivity.

Therefore, in this embodiment, the workpiece W is made of copper, which is a high reflectance material with a low laser absorption rate. The workpiece W may be made of gold or silver.

<Operation of laser processing equipment>
By the way, the short-wave first laser beam L1 has a high laser absorption rate with respect to the workpiece W made of a high reflectance material such as copper, but the maximum output of the laser beam is low. Therefore, in order to obtain the required weld bead width, the beam diameter must be increased, but the power density is lowered, so the processing speed must be slowed down.

On the other hand, the long-wavelength second laser beam L2 has a higher maximum laser beam output than the short-wavelength first laser beam L1, but has a low laser absorptance with respect to the workpiece W made of a high reflectance material. Therefore, it is difficult to make the penetration depth of the workpiece W constant with the long-wavelength second laser beam L2, and there is a possibility that the machining quality may deteriorate.

Therefore, in the present embodiment, by devising the emission positions of the first laser beam L1 and the second laser beam L2, the machining quality and machining speed of the workpiece W can be improved.

As shown in FIG. 3, the laser processing head 20 emits a short-wavelength first laser beam L1 to the workpiece W. As shown in FIG. At the laser start position, the laser processing head 20 emits a short-wavelength first laser beam L1 in a pulsed manner. Thus, even if the first laser beam L1 has a low power density, the workpiece W is sufficiently preheated by repeatedly emitting the first laser beam L1 in a pulse shape to increase the total output. As a result, a preheating portion 30 in which a part of the workpiece W is melted is formed at the laser start position.

Specifically, the laser processing head 20 emits the first laser beam L1, which has a high laser absorption rate with respect to a high reflectance material, prior to the surface of the work W, thereby oxidizing the surface of the work W, The surface of W is partially melted first to modify the surface.

The first detector 28 detects the amount of scattered light of the short-wavelength first laser beam L1 at the laser start position. The detection result of the first detector 28 is sent to the controller 5 . When the amount of scattered light of the first laser beam L1 is smaller than a predetermined threshold value, the control unit 5 determines that the workpiece W has been sufficiently preheated and the preheating unit 30 has been formed.

As shown in FIG. 4, the laser processing head 20 changes the emission position of the first laser beam L1 by adjusting the angle of the first adjustment mechanism 24 (see FIG. 1). Specifically, the first laser beam L1 is emitted forward in the processing direction (leftward in FIG. 4) from the laser start position. A preheating section 30 is formed in the workpiece W along the emission path of the first laser beam L1.

The laser processing head 20 emits the second laser beam L2 to the laser start position. Since the laser start position is preheated by the first laser beam L1, the workpiece W is likely to absorb the second laser beam L2. A molten pool 31 is formed at the laser start position by the second laser beam L2.

Specifically, when the light amount of the scattered light of the first laser beam L1 is smaller than a predetermined threshold, it is determined that the work W has been sufficiently preheated and the preheating portion 30 is formed, and the laser processing head 20 , immediately after the portion of the work W of the high reflectance material where the surface modification is performed by the short wavelength first laser light L1 having a high laser absorptance with respect to the work W of the high reflectance material. , emits a second laser beam L2 having a high power density and a long wavelength. As a result, the second laser beam L2, which has a low laser absorptance with respect to the work W made of a high reflectance material, is easily absorbed by the work W made of a high reflectance material.

As shown in FIG. 5, the laser processing apparatus 1 moves the laser processing head 20 in the processing direction. The laser processing head 20 emits the first laser beam L1 and the second laser beam L2 to the workpiece W continuously.

The laser processing head 20 emits the first laser beam L1, which has a high laser absorptance with respect to a high reflectance material, to the surface of the workpiece W prior to the laser beam L1. By emitting the first laser beam L1, the workpiece W is preheated, and the preheating portion 30 is formed.

The laser processing head 20 emits a second laser beam L2 having a high power density to the preheating portion 30 of the work W. As shown in FIG. Thereby, the second laser beam L2 is easily absorbed by the workpiece W, and the molten pool 31 can be formed in a short time. When the molten pool 31 solidifies, a weld bead 32 is formed and the first member W1 and the second member W2 of the workpiece W are welded.

In this way, the laser processing head 20 emits at least part of the first laser beam L1 forward in the moving direction relative to the second laser beam L2, so that the second laser beam L2 is easily absorbed. A preheating section 30 is formed. The laser processing head 20 modifies the surface of the work W with the first laser beam L1 prior to the second laser beam L2, and emits the surface of the work W after the surface modification with the second laser beam L2. laser processing. Thereby, the processing quality and processing speed of the workpiece can be improved.

Here, even during the movement of the laser processing head 20, by detecting the amount of scattered light of the short-wavelength first laser beam L1 by the first detection unit 28, preheating is performed after the preheating unit 30 is sufficiently formed. The long-wavelength second laser beam L2 can be stably emitted to the portion 30 with good timing.

As shown in FIG. 5, the laser processing head 20 emits the first laser beam L1 and the second laser beam L2 to the workpiece W while adjusting the angle of the first adjustment mechanism 24 (see FIG. 1). , the first laser beam L1 relative to the second laser beam L2 so that at least part of the first laser beam L1 is emitted forward in the processing direction (moving direction) relative to the second laser beam L2. Change the exit position of The first laser beam L1 is emitted ahead of the second laser beam L2 in the processing direction, and the second laser beam L2 is emitted so as to at least follow the first laser beam L1 in the processing direction.

More specifically, the laser processing head 20 changes the emission position of the first laser beam L1 between the front position and the rear position. At the front position, the first laser beam L1 is positioned ahead of the second laser beam L2 in the processing direction. At the rear position, the first laser beam L1 is positioned behind the second laser beam L2 in the processing direction.

In this way, at the front position, the surface of the work W is partially melted and roughened by the short-wavelength first laser beam L1 in advance as surface modification, and then the long-wavelength second laser beam L2 is used to roughen the surface of the work W. By performing the finish machining of , the machining quality and machining speed of the workpiece W can be improved.

Further, at the rear position, the first laser beam L1 with a short wavelength is emitted behind the second laser beam L2 with a long wavelength, so that the surface of the workpiece W machined with the second laser beam L2 can be cleaned. can. For example, by emitting the first laser beam L1 to the weld bead 32 solidified after welding with the second laser beam L2, the slag can be removed and the appearance of the weld bead 32 can be made smooth. Further, by emitting the first laser beam L1 behind the second laser beam L2 at the laser end position, it is possible to suppress the occurrence of craters.

In this embodiment, the case of laser welding the work W has been described, but the present invention can also be applied to the case of laser cutting the work W. For example, by emitting the first laser beam L1 to the cut surface laser-cut by the second laser beam L2, the cut surface can be cleaned.

<<Embodiment 2>>
In the following, the same reference numerals are given to the same parts as in the first embodiment, and only the points of difference will be described.

As shown in FIG. 6 , the laser processing head 20 has a first detector 28 and a second detector 38 . The first detection unit 28 detects the amount of scattered light of the short-wavelength first laser light L<b>1 that has been reflected by the workpiece W and passed through the first filter 29 . The detection result of the first detector 28 is sent to the controller 5 .

The second detector 38 is composed of, for example, a photodiode. The second detection unit 38 detects data indicating the melting state of the workpiece W at the processing position. Here, the data indicating the molten state detected by the second detection unit 38 is the amount of scattered light of the long-wavelength second laser beam L2 reflected by the workpiece W. As shown in FIG.

A second filter 39 is arranged between the second detector 38 and the workpiece W. As shown in FIG. The second filter 39 shields the scattered light of the first short-wavelength laser beam L1 reflected by the workpiece W, while allowing the scattered light of the second long-wavelength laser beam L2 to pass through.

The second detector 38 detects the amount of scattered light of the long-wavelength second laser beam L2 that has passed through the second filter 39 . The detection result of the second detection section 38 is sent to the control section 5 .

When the amount of scattered light of the long-wavelength second laser beam L2 detected by the second detection unit 38 is smaller than a predetermined threshold value, the control unit 5 controls the second laser beam L2 so as to increase the output power of the second laser beam L2. 2 controls the operation of the laser oscillator 12;

Specifically, the amount of scattered light of the long-wavelength second laser beam L2 changes according to the melted state of the surface of the workpiece W. As shown in FIG. For example, when the surface of the workpiece W is not sufficiently melted by the second laser beam L2, the amount of scattered light of the second laser beam L2 increases. On the other hand, when the surface of the workpiece W is sufficiently melted by the second laser beam L2, the amount of scattered light of the second laser beam L2 is reduced.

Therefore, after emitting the long-wavelength second laser beam L2 at a low output, the melting of the workpiece W is detected by the second detection unit 38 based on the amount of scattered light of the long-wavelength second laser beam L2. By determining and processing the work W by increasing the output of the second laser beam L2 stepwise or gradually, it is possible to suppress the occurrence of spatter and increase the processing quality and processing speed of the work W.

-Modification 1 of Embodiment 2-
In the laser processing apparatus 1 shown in FIG. 6, the control unit 5 detects the amount of scattered light of the long-wavelength second laser beam L2 detected by the second detection unit 38 is higher than a predetermined threshold value. The operation of the laser processing head 20 is controlled so as to emit the first laser beam L1 to the processing position.

As a result, after the long-wavelength second laser beam L2 is emitted to the work W, the second detection unit 38 detects that the work W is not sufficiently melted. By emitting the short-wave first laser beam L1 to the processing position of the workpiece W made of a highly reflective material based on the amount of light, the melting of the workpiece W made of a highly reflective material can be promoted.

-Modification 2 of Embodiment 2-
In the laser processing apparatus 1 shown in FIG. 6 , the control unit 5 controls when the amount of scattered light of the long-wavelength second laser beam L2 detected by the second detection unit 38 is higher than a predetermined threshold value. The operation of the first laser oscillator 11 is controlled so as to increase the output of the first laser light L1 stepwise or gradually.

As a result, after the long-wavelength second laser beam L2 is emitted to the workpiece W made of the highly reflective material, the second long-wavelength laser beam L2 detected by the second detector 38 detects that the workpiece W is not sufficiently melted. Based on the amount of scattered light of the light L2, the first laser beam L1 with a short wavelength is emitted at a high output to sufficiently preheat the work W, thereby suppressing spatter and making the work W of a highly reflective material. can promote the melting of

-Modification 3 of Embodiment 2-
In the laser processing apparatus 1 shown in FIG. 6, the controller 5 controls the second laser beam L2 when the amount of scattered light of the long-wavelength second laser beam L2 detected by the second detector 38 is higher than a predetermined upper limit value. The operation of the second laser oscillator 12 is controlled so as to stop the output of the laser light L2 (see FIG. 7).

As a result, it is possible to prevent the laser processing head 20 from being damaged due to the scattered light of the high-power second laser beam L2 reflected by the workpiece W being irradiated to the laser processing head 20 .

The first laser oscillator 11 continues laser oscillation and preheats the workpiece W with the first laser beam L1 having a short wavelength, thereby promoting the melting of the workpiece W made of a highly reflective material.

<<Other embodiments>>
The above embodiment may be configured as follows.

In the present embodiment, the first detection section 28 and the second detection section 38 are composed of photodiodes, but the configuration is not limited to this. For example, a camera, a temperature sensor, an optical interferometer, etc. may be used as the first detection unit 28 and the second detection unit 38 .

For example, when a camera is used, the data indicating the molten state of the work W is imaging data obtained by imaging the outline of the preheating portion 30 or the molten pool 31 formed at the processing position of the work W. Then, when the outer diameter of the preheating portion 30 or the molten pool 31 is larger than a predetermined threshold value (for example, the beam diameter of the second laser beam L2), it can be determined that the workpiece W is sufficiently melted.

Further, when a temperature sensor is used, the data indicating the molten state of the work W is the temperature of the work W at the processing position. Then, if the temperature of the workpiece W to be processed is higher than a predetermined threshold value (for example, the melting point of the workpiece W), it can be determined that the workpiece W is sufficiently melted.

Further, when an optical interferometer is used, the data indicating the molten state of the workpiece W is the penetration depth of the keyhole of the molten pool 31 formed at the processing position of the workpiece W. FIG. If the penetration depth of the keyhole is not so deep, the vibration of the surface of the molten pool 31 is measured. Then, if the penetration depth of the keyhole or the vibration of the surface of the molten pool 31 is greater than a predetermined threshold value, it can be determined that the workpiece W is sufficiently melted.

In this embodiment, the robot 2 moves the laser processing head 20 to change the position of the laser processing head 20 with respect to the workpiece W, but the present invention is not limited to this form. For example, the work W may be mounted on a moving table (not shown), and the work W may be moved relative to the laser processing head 20 .

In addition, the laser processing head 20 and the moving table on which the work W is mounted are relatively moved, and the first laser beam L1 and the second laser beam L2 are moved relatively to the work W for processing. can be

In the present embodiment, a configuration in which the short-wavelength first laser beam L1 and the long-wavelength second laser beam L2 are emitted from one laser processing head 20 has been described, but the present invention is not limited to this configuration. For example, a configuration in which a laser processing head that emits the short-wavelength first laser beam L1 and a laser processing head that emits the long-wavelength second laser beam L2 are provided separately may be used.

INDUSTRIAL APPLICABILITY As described above, the present invention is extremely useful and has high industrial applicability because it can obtain the highly practical effect of being able to improve the machining quality and machining speed of a workpiece.

Reference Signs List 1 laser processing device 5 control section 11 first laser oscillator 12 second laser oscillator 20 laser processing head 21 first collimator lens 22 second collimator lens 24 first adjustment mechanism 25 second adjustment mechanism 26 dichroic mirror (first optical member)
27 fθ lens (second optical member)
28 first detector 38 second detector L1 first laser beam L2 second laser beam W workpiece

Claims (9)

A laser processing device that processes a workpiece by emitting a laser beam,
a first laser oscillator that oscillates a first laser beam;
a second laser oscillator that oscillates a second laser beam having a wavelength longer than that of the first laser beam;
a laser processing head that emits the first laser beam and the second laser beam incident from the first laser oscillator and the second laser oscillator to the work,
The laser processing head is
a first collimating lens that parallelizes the first laser light;
a second collimating lens that parallelizes the second laser light;
a first optical member that superimposes the first laser light and the second laser light that have passed through the first collimating lens and the second collimating lens;
a second optical member for focusing the first laser beam and the second laser beam superimposed by the first optical member toward the workpiece;
and a first adjustment mechanism that adjusts the incident position of the first laser beam with respect to the first optical member and relatively changes the emission position of the first laser beam with respect to the second laser beam. laser processing equipment. In claim 1,
A second adjustment mechanism is provided for adjusting the incident position of the second laser beam with respect to the first optical member and relatively changing the emission position of the second laser beam with respect to the first laser beam. laser processing equipment. In claim 1 or 2,
a detection unit that detects data indicating a molten state at the processing position of the workpiece;
and a controller for controlling the operation of at least one of the laser processing head, the first laser oscillator, and the second laser oscillator based on data detected by the detector. processing equipment. In claim 3,
The detection unit includes a first detection unit that detects data indicating a melted state at a processing position of the workpiece corresponding to the first laser beam,
By oscillating the first laser oscillator and stopping the second laser oscillator, the first laser beam is emitted from the laser processing head,
The first detection unit detects the amount of scattered light of the first laser beam reflected by the workpiece,
The control unit causes the second laser oscillator to oscillate when the light amount of the scattered light detected by the first detection unit is lower than a predetermined threshold value, and moves the laser beam from the laser processing head to the processing position of the workpiece. A laser processing apparatus that emits a second laser beam. In claim 3,
The detection unit includes a second detection unit that detects data indicating a melted state at a processing position of the workpiece corresponding to the second laser beam,
By oscillating the first laser oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head,
The second detection unit detects the amount of scattered light of the second laser beam reflected by the workpiece,
The control unit controls the second laser beam so as to increase the output of the second laser beam stepwise or gradually when the amount of the scattered light detected by the second detection unit is lower than a predetermined threshold value. A laser processing apparatus characterized by controlling the operation of an oscillator. In claim 3,
The detection unit includes a second detection unit that detects data indicating a melted state at a processing position of the workpiece corresponding to the second laser beam,
By oscillating the first laser oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head,
The second detection unit detects the amount of scattered light of the second laser beam reflected by the workpiece,
The control unit controls the laser processing head so as to emit the first laser beam to a processing position of the workpiece when the amount of the scattered light detected by the second detection unit is higher than a predetermined threshold value. A laser processing device characterized by controlling the operation of In claim 3,
The detection unit includes a second detection unit that detects data indicating a melted state at a processing position of the workpiece corresponding to the second laser beam,
By oscillating the first laser oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head,
The second detection unit detects the amount of scattered light of the second laser beam reflected by the workpiece,
The controller controls the first laser beam so as to increase the output of the first laser beam stepwise or gradually when the amount of the scattered light detected by the second detector is higher than a predetermined threshold value. A laser processing apparatus characterized by controlling the operation of an oscillator. In claim 3,
The detection unit includes a second detection unit that detects data indicating a melted state at a processing position of the workpiece corresponding to the second laser beam,
By oscillating the first laser oscillator and the second laser oscillator, the first laser beam and the second laser beam are emitted from the laser processing head,
The second detection unit detects the amount of scattered light of the second laser beam reflected by the workpiece,
The control unit operates the second laser oscillator to stop outputting the second laser light when the amount of the scattered light detected by the second detection unit is higher than a predetermined upper limit. A laser processing device characterized by controlling In any one of claims 3 to 8,
A laser processing apparatus, wherein the detection unit is composed of a photodiode.