JP2023112731A - Laser machining device - Google Patents

Abstract

To enhance the machining quality and machining speed of work-piece in a laser machining device.SOLUTION: A laser machining head 20 emits a first laser beam L1 of short wavelength and a second laser beam L2 of long wavelength. The laser machining head 20 moves in a predetermined direction relatively with respect to work-piece W. The laser machining head 20 emits at least a part of the first laser beam L1 to a front side in the moving direction than the second laser beam L2. So as to make it easy to absorb the second laser beam L2, the surface modification of the work-piece W is performed with the first laser beam L1 prior to the second laser beam L2, and a surface of the work-piece W subjected to the surface modification is laser-machined by further emitting the second laser beam L2.SELECTED DRAWING: Figure 4

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, which have a relatively high laser light reflectance compared to iron. The maximum output of laser light is small. 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, long-wavelength laser light has a larger beam diameter and a higher maximum output than short-wavelength laser light. However, long-wavelength laser light has a low laser absorptance with respect to a workpiece made of a high-reflectance material, making it difficult to make the penetration depth constant, and there is a risk of deterioration in processing quality.

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 a workpiece, and includes a laser processing head that emits a first laser beam and a second laser beam having a longer wavelength than the first laser beam. and a movement mechanism for moving the laser processing head relative to the workpiece along a predetermined movement direction, wherein the laser processing head converts at least part of the first laser beam into the second laser beam. performing surface modification of the workpiece with the first laser beam prior to the second laser beam so that the workpiece is emitted forward in the moving direction than the laser beam and the second laser beam is easily absorbed; The surface of the work whose surface has been modified is further irradiated with the second laser beam for laser processing.

In the first invention, the laser processing head emits a short-wavelength first laser beam and a long-wavelength second laser beam. The laser processing head moves relative to the work along a predetermined movement direction. At least part of the first laser beam is emitted forward in the moving direction relative to the second laser beam.

In this way, after roughening the surface of the workpiece with the short-wavelength first laser beam, the workpiece is processed with the long-wavelength second laser beam, thereby improving the processing quality and processing speed of the workpiece. can.

Specifically, the short-wavelength first laser light (for example, laser light of 600 nm or less) has a high laser absorptance 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 (eg, laser beam of 800 nm or longer) has a low laser absorptance with respect to a workpiece made of a high reflectance material, but has a high maximum laser beam output.

Therefore, by emitting the first laser beam at least to the surface of the work in advance, the surface of the work is oxidized, the surface of the work is partially melted first, and the surface is modified. By emitting the second laser beam to the cut portion, the second laser beam is easily absorbed by the workpiece. Thereby, the processing quality and processing speed of the workpiece can be improved.

A second invention is based on the first invention, further comprising an emission position changing section for changing an emission position of the first laser light, wherein the emission position changing section changes at least part of the first laser light to the second laser light. Between a first position located forward of the laser light in the movement direction and a second position located rearward of the second laser light in the movement direction at least part of the first laser light, It is characterized by changing the emission position of the first laser beam.

In the second invention, the emission position of the first laser light is changed between the first position and the second position. At the first position, at least part of the first laser beam is located ahead of the second laser beam in the moving direction. At the second position, at least part of the first laser beam is located behind the second laser beam in the movement direction.

In this way, by emitting the first laser beam behind the second laser beam as well, it is possible to clean the processing surface of the workpiece processed by the second laser beam.

For example, specifically, by emitting the first laser beam to the weld bead solidified after welding with the second laser beam, the slag can be removed and the appearance of the weld bead can be smoothed. Further, by emitting the first laser beam behind the second laser beam at the laser end position, it is possible to suppress the occurrence of craters. 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.

A third invention is based on the first or second invention, further comprising an emission position changing section that changes an emission position of the first laser beam, wherein the emission position changing section extends in a width direction intersecting the movement direction. It is characterized by periodically reciprocating along the line to change the emission position of the first laser light.

In the third invention, in other words, the emission position of the first laser light is periodically and finely reciprocated along the width direction intersecting the movement direction.

By emitting the first laser beam in the width direction in this manner, even with the first laser beam having a small beam diameter, it is possible to modify the surface of a wide range of the workpiece.

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. FIG. 2 is a plan view showing a state of a workpiece before laser processing; FIG. 4 is a plan view showing a state during laser processing of a work; FIG. 5 is a plan view showing a state during laser processing in Modification 1 of Embodiment 1; FIG. 9 is a plan view showing a state during laser processing in Modification 2 of Embodiment 1; FIG. 11 is a plan view showing a state of a workpiece before laser processing according to Embodiment 2; FIG. 4 is a plan view showing a state during laser processing of a work; FIG. 11 is a plan view showing a state during laser processing in Modification 1 of Embodiment 2; FIG. 10 is a plan view showing a state during laser processing in Modification 2 of Embodiment 2;

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 ( movement mechanism) 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 first laser light L1 is short-wave 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 second laser light L2 is a long wavelength laser light with a wavelength of 800 nm or more (for example, about 800 nm to 10800 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 second mirror 24, a biaxial MEMS mirror 25 (output position changing unit), a dichroic mirror 26, and an fθ lens 27 .

The first collimator lens 21 collimates the first laser beam L1 emitted from the emission end of the first transmission fiber 15 . The first mirror 23 reflects the first laser beam L1 collimated by the first collimator lens 21, and is biaxial with a variable mirror angle so that the emission position of the first laser beam L1 with respect to the workpiece W can be changed. The light is guided to the MEMS mirror 25 .

Here, by moving the first collimating lens 21 and the second collimating 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 second collimator lens 22 collimates the second laser beam L2 emitted from the emission end of the second transmission fiber 16 . The second mirror 24 reflects the second laser beam L2 collimated by the second collimator lens 22 and guides it to the dichroic mirror 26 .

The biaxial MEMS mirror 25 further reflects the first laser beam L<b>1 reflected by the first mirror 23 and guides it to the dichroic mirror 26 . The biaxial MEMS mirror 25 changes the incident position of the first laser beam L1 with respect to the dichroic mirror 26 by changing the mirror angle in two axial directions. A configuration using a biaxial galvanometer may be used instead of the biaxial MEMS mirror 25 .

The dichroic mirror 26 transmits the second laser beam L2 and reflects the first laser beam L1. The dichroic mirror 26 guides the first laser beam L1 and the second laser beam L2 to the fθ lens 27 .

The dichroic mirror 26 transmits the second laser beam L2 and reflects the first laser beam L1. The dichroic mirror 26 guides the first laser beam L1 and the second laser beam L2 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 emission position of the first laser beam L1 with respect to the workpiece W can be changed by changing the angle of the biaxial MEMS mirror 25 to move the incident position of the first laser beam L1 with respect to the fθ lens 27. ing.

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 (moving 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

The work W is formed in a plate shape, for example. 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 absorption rate.

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 low laser absorptance with respect to the workpiece W made of a high reflectance material, but has a higher maximum laser beam output than the short-wavelength first laser beam L1. However, the second laser beam L2 having a long wavelength has a low laser absorptance with respect to the workpiece W made of a high reflectance material, and it is difficult to make the penetration depth constant, and there is a possibility that the processing 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 emission position of the first laser beam L1 is set to a position ahead of the second laser beam L2 in the processing direction (leftward in FIG. 3). As shown in FIG. 4, the laser processing apparatus 1 emits the first laser beam L1 and the second laser beam L2 to the workpiece W while moving the laser processing head 20 in the processing direction (moving direction). At this time, after the surface of the workpiece W is first roughened by the short-wavelength first laser beam L1, the workpiece W is cut by the long-wavelength second laser beam L2.

Specifically, the laser processing head 20 oxidizes the surface of the work W by emitting the first laser beam L1, which has a high laser absorptance with respect to a high reflectance material, prior to the surface of the work W. Surface modification such as partially melting the surface of is performed first.

Then, the laser processing head 20 applies the short-wave first laser beam L1 having a high laser absorptance to the work W made of a high reflectance material to treat the surface-modified portion of the work W made of a high reflectance material. , and immediately after that, the second laser beam L2 having a high power density and a long wavelength is emitted, so that the second laser beam L2 having a low laser absorptance with respect to the work W of the high reflectance material is emitted from the high reflectance material. is easily absorbed by the workpiece W. In other words, the laser processing head 20 emits at least part of the first laser beam L1 forward of the second laser beam L2 in the movement direction, and the second laser beam L2 is easily absorbed by the second laser beam L2. Prior to the second laser beam L2, the surface of the workpiece W is modified by the first laser beam L1, and the surface of the workpiece W after the surface modification is further emitted by the second laser beam L2 for laser processing. Thereby, the processing quality and processing speed of the workpiece can be improved.

-Modification 1 of Embodiment 1-
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. 5, the laser processing apparatus 1 emits a first laser beam L1 and a second laser beam L2 to the workpiece W while moving the laser processing head 20 in the processing direction (leftward in FIG. 5). do. 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.

The laser processing head 20 emits the first laser beam L1 and the second laser beam L2 to the workpiece W, and adjusts the angle of the biaxial MEMS mirror 25 (see FIG. 1) whose angle can be changed in two axial directions. Thus, the emission position of the first laser beam L1 is changed.

Specifically, the laser processing head 20 changes the emission position of the first laser beam L1 between the first position and the second position. At the first position, the first laser beam L1 is located ahead of the second laser beam L2 in the processing direction. At the second position, the first laser beam L1 is located behind the second laser beam L2 in the processing direction.

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

At the second position, the first laser beam L1 is also emitted behind the second laser beam L2, so that the surface of the workpiece W machined with the second laser beam L2 can be cleaned. For example, specifically, by emitting the first laser beam L1 to the weld bead solidified after welding with the second laser beam L2, the slag can be removed and the appearance of the weld bead 30 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 addition, by emitting the first laser beam L1 onto the cut surface laser-cut by the second laser beam L2, the cut surface can be cleaned.

-Modification 2 of Embodiment 1-
As shown in FIG. 6, the laser processing apparatus 1 emits a first laser beam L1 and a second laser beam L2 to the workpiece W while moving the laser processing head 20 in the processing direction (leftward in FIG. 6). do. The first laser beam L1 is emitted at least forward in the processing direction from the second laser beam L2.

The laser processing head 20 emits the first laser beam L1 and the second laser beam L2 to the workpiece W, and adjusts the angle of the biaxial MEMS mirror 25 (see FIG. 1) whose angle can be changed in two axial directions. Thus, the emission position of the first laser beam L1 is changed.

Specifically, the laser processing head 20 periodically and finely reciprocates the emission position of the first laser beam L1 along the width direction (vertical direction in FIG. 6) intersecting (for example, perpendicular to) the processing direction. .

By emitting the first laser beam L1 in the width direction in this manner, even with the first laser beam L1 having a small beam diameter, it is possible to modify the surface of a wide range of the workpiece W.

<<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. 7, two plate-shaped workpieces W are arranged as a butt joint so that their side edges face each other. The workpiece W is made of copper, which is a highly reflective material. The workpiece W may be made of aluminum or magnesium.

The emission position of the first laser beam L1 is set at a position straddling two works W in the emission direction. The emission position of the second laser beam L2 is set at a position straddling at least two works W. As shown in FIG. Also, the emission position of the first laser beam L1 is set to a position ahead of the second laser beam L2 in the processing direction (leftward in FIG. 7).

As shown in FIG. 8, the laser processing apparatus 1 emits laser light along positions where two works W face each other while moving the laser processing head 20 in the processing direction. At this time, the surface of the workpiece W is first roughened by the short-wavelength first laser beam L1, and then the workpiece W is welded by the long-wavelength second laser beam L2.

Specifically, the laser processing head 20 emits the short-wavelength first laser beam L1 having a high laser absorptance with respect to a high-reflectance material at least prior to the surface of the workpiece W as the high-reflectance material, Surface modification such as oxidizing the surface of the work W or partially melting the surface of the work W is performed.

Then, the laser processing head 20 follows the second laser beam L2 with a high power density and a long wavelength in the processing direction with respect to the portion of the workpiece W on which surface modification has been performed by the first laser beam L1 with a short wavelength. As a result, the long-wavelength second laser beam L2, which has a low laser absorptance with respect to the work W of a high reflectance material, is absorbed by the work W of a high reflectance material with a low laser absorptance, and the work W is Easier to melt. When the melted workpiece W solidifies, a weld bead 30 is formed behind in the processing direction. In other words, the meltability of the workpiece W made of high reflectance material is promoted. Thereby, the two works W can be welded together.

-Modification 1 of Embodiment 2-
As shown in FIG. 9, the laser processing head 20 adjusts the angle of the biaxial MEMS mirror 25 (see FIG. 1) while emitting the first laser beam L1 and the second laser beam L2 to the workpiece W. , the emission position of the first laser beam L1 is changed.

Specifically, the laser processing head 20 changes the emission position of the first laser beam L1 between the first position and the second position. At the first position, the first laser beam L1 is located ahead of the second laser beam L2 in the processing direction. At the second position, the first laser beam L1 is located behind the second laser beam L2 in the processing direction.

Thus, at least at the first position, the surface of the workpiece W is roughened first with the short-wavelength first laser beam L1, and then the workpiece W is processed with the long-wavelength second laser beam L2. The processing quality and processing speed of W can be enhanced.

At the second position, the first laser beam L1 is also emitted behind the second laser beam L2, so that the surface of the workpiece W machined with the second laser beam L2 can be cleaned. For example, the slag generated by the second laser beam L2 can be removed by emitting the first laser beam L1 to the weld bead 30 solidified after welding with the second laser beam L2.

-Modification 2 of Embodiment 2-
As shown in FIG. 10, the first laser beam L1 is emitted at least ahead of the second laser beam L2 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, and adjusts the angle of the biaxial MEMS mirror 25 (see FIG. 1) to produce the first laser beam L1. Change the exit position of

Specifically, the laser processing head 20 periodically and finely reciprocates the emission position of the first laser beam L1 along the width direction (vertical direction in FIG. 10) that intersects the processing direction.

By emitting the first laser beam L1 in the width direction in this manner, even if the beam diameter of the first laser beam L1 is small, the second laser beam can be easily absorbed in a wide range of the workpiece W. The surface can be modified by the first laser beam L1 prior to the second laser beam.

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

In the present embodiment, the entire first laser beam L1 is emitted forward in the processing direction from the second laser beam L2. may also be emitted forward in the processing direction.

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 workpiece W may be mounted on a moving table (not shown), and the laser processing head 20 may be moved relative to the workpiece W.

In the present embodiment, the configuration in which the first laser beam L1 and the 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 first laser beam L1 and a laser processing head that emits the 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.

1 laser processing device 2 robot (moving mechanism)
20 laser processing head 25 2-axis MEMS mirror (emission position changing unit)
L1 First laser beam L2 Second laser beam W Work

Claims (3)

A laser processing device that emits a laser beam to a work,
a laser processing head that emits a first laser beam and a second laser beam having a longer wavelength than the first laser beam;
a moving mechanism for relatively moving the laser processing head with respect to the work along a predetermined moving direction;
The laser processing head emits at least part of the first laser beam forward in the movement direction relative to the second laser beam, and the second laser beam is arranged to facilitate absorption of the second laser beam. A laser characterized in that the surface of the work is modified by the first laser beam prior to the light, and the surface of the work whose surface has been modified is further emitted by the second laser beam for laser processing. processing equipment. In claim 1,
An emission position changing unit that changes the emission position of the first laser light,
The emission position changing unit has a first position where at least a portion of the first laser beam is located ahead of the second laser beam in the moving direction, and a first position where at least a portion of the first laser beam is located ahead of the second laser beam. A laser processing apparatus, wherein the emission position of the first laser beam is changed between a second position located behind the laser beam in the moving direction. In claim 1 or 2,
An emission position changing unit that changes the emission position of the first laser light,
The laser processing apparatus, wherein the emission position changing unit periodically reciprocates along a width direction intersecting the moving direction to change the emission position of the first laser beam.