JP6824092B2 - Laser processing method and laser processing equipment - Google Patents

Description

The present invention relates to a laser processing method and a laser processing apparatus that irradiate a work material with a laser beam to cut the work material.

Conventionally, when cutting a work material with a laser cutting device, an assist gas is injected from a laser nozzle toward the work material and a set cutting path is moved while irradiating a laser beam to form a cutting groove. Cut the work material.

When cutting a work material with a laser cutting device, cutting defects such as self-burning, notch, blow-up, and dross adhesion on the back surface of the work material may occur.

Among them, self-burning, notch, and blow-up can be detected from the surface side of the material to be processed by image identification and change in the amount of visible light, and various techniques are disclosed (for example, Patent Documents). See 1.).

Japanese Unexamined Patent Publication No. 09-029469

However, it is difficult to visually confirm the dross adhering to the back surface side of the work material from the front surface side of the work material, and there is no choice but to check by turning over the product after cutting the work material. If dross is attached, post-treatment for removing the dross is very difficult, requires a large amount of personnel and time, and may be irreparable and must be made defective.

The present invention has been made in consideration of such circumstances, and is a laser processing method and a laser processing apparatus capable of efficiently suppressing cutting defects caused by dross adhering to the back surface side of the material to be processed. The purpose is to provide.

When the inventor of the present invention irradiates a work material with a laser beam to cut the material, the cutting groove is irradiated with the cutting laser beam to form a cutting groove, and then the cutting groove is irradiated with the inspection laser beam. Dross radiated light (for example, visible light emitted by red-heated dross, infrared rays, etc.) and reflected light reflected by the dross by the inspection laser beam can be detected from the dross heated by the inspection laser beam. Since the intensity of dross radiated light and reflected light changes depending on the state of dross adhering to the back surface side of the processed material, the dross detection light containing at least one of the dross radiated light and the reflected light is detected to detect the dross. It was found that the dross adhesion status on the back surface side of the cutting groove can be grasped based on the strength.

In order to solve the above problems, the present invention proposes the following means.
The invention according to claim 1 is a laser processing method of irradiating a work material with a laser beam to cut the work material.
A cutting laser beam is irradiated from the surface side of the material to be processed to form a cutting groove, and the inspection laser beam is irradiated from the surface side while moving along the cutting groove, and the inspection laser beam is used. The inspection laser beam detects the dross detection light including at least one of the dross radiated light emitted from the heated dross and the reflected light reflected by the dross, and the back side of the cutting groove is based on the dross detection light. It is characterized by determining the dross adhesion status of.

The invention according to claim 3 is a laser processing apparatus that irradiates a work material with a laser beam to cut the work material, and is a laser that injects an assist gas from a nozzle hole and irradiates a cutting laser beam. The processing head, the cutting laser beam irradiation unit that irradiates the cutting laser beam, the cutting laser oscillator that outputs the cutting laser beam, the inspection laser beam irradiation unit that irradiates the inspection laser beam, and the above. An inspection laser oscillator that outputs an inspection laser beam, a dross radiated light emitted from a dross heated by the inspection laser beam, and at least one of the reflected light reflected by the inspection laser beam by the dross. It is provided with a dross detection light detection unit that detects the included dross detection light, an assist gas supply means that supplies the assist gas to the laser processing head, a laser processing head moving means that moves the laser processing head, and a control unit. The control unit irradiates the cutting laser beam from the surface side of the work material to form a cutting groove, and irradiates the inspection laser beam from the surface side while moving along the cutting groove. It is characterized in that the dross adhesion state on the back surface side of the cutting groove is determined based on the dross detection light detected by the dross detection light detection unit.

According to the laser processing method and laser processing apparatus according to the present invention, a cutting laser beam is irradiated from the surface side of the material to be processed to form a cutting groove, and the inspection laser is moved from the surface side while moving along the cutting groove. While irradiating the beam, the dross detection light including at least one of the dross radiated light emitted from the dross heated by the inspection laser beam and the reflected light reflected by the dross is detected by the inspection laser beam, and the dross is detected. Since the dross adhesion status on the back surface side of the cutting groove is determined based on the detection light, the dross adhesion status on the back surface side of the cutting groove can be easily and efficiently determined.
As a result, it is possible to efficiently suppress cutting defects caused by dross adhering to the back surface side of the material to be processed.

The invention according to claim 2 is the laser processing method according to claim 1, wherein the dross adhesion state on the back surface side of the cutting groove is determined based on the ratio of the intensity of the dross detection light exceeding the threshold value. It is a feature.

The invention according to claim 4 is the laser processing apparatus according to claim 3, wherein the control unit has a dross adhesion state on the back surface side of the cutting groove based on a ratio in which the intensity of the dross detection light exceeds a threshold value. It is characterized in that it is configured to judge.

According to the laser processing method and the laser processing apparatus according to the present invention, the dross adhesion state on the back surface side of the cutting groove is determined based on the ratio of the intensity of the dross detection light exceeding the threshold value. You can make a stable judgment.

The invention according to claim 5 is the laser processing apparatus according to claim 3 or 4, wherein the output of the oscillator used for the output of the cutting laser beam is reduced to irradiate the laser beam for inspection. The dross detection light detection unit arranged inside the laser processing head is configured to detect the dross detection light.

According to the laser processing apparatus according to the present invention, the output of the oscillator used for the output of the cutting laser beam is reduced to irradiate the laser beam for inspection, and the dross detection light detection unit is arranged inside the laser processing head. Since it is configured to detect the dross detection light, it is possible to suppress the simplification of the structure, the increase in size of the laser processing apparatus, and the increase in manufacturing cost.

The invention according to claim 6 is the laser processing apparatus according to claim 3 or 4, and reflects the wavelength band of the cutting laser beam between the cutting laser beam irradiation unit and the nozzle hole. A specific wavelength band reflection mirror that transmits the dross detection light is arranged, and the inspection laser beam irradiated with the cutting laser beam and the output of the oscillator used for the output of the cutting laser beam reduced to the specific wavelength band. It is reflected by the reflection mirror and irradiated from the nozzle hole, and the visible light at the processing point by the dross detection light transmitted through the specific wavelength band reflection mirror is detected by the optical sensor arranged behind the specific wavelength band reflection mirror. It is characterized in that it is configured as follows.

According to the laser processing apparatus according to the present invention, a specific wavelength band reflection mirror is arranged between the cutting laser beam irradiation unit and the nozzle hole, and the output of the cutting laser beam and the oscillator used for the output of the cutting laser beam is output. The inspection laser beam that has been made small and irradiated is reflected by the specific wavelength band reflection mirror and irradiated from the nozzle hole, and the dross detection light transmitted through the specific wavelength band reflection mirror by the optical sensor placed behind the specific wavelength band reflection mirror. Since the visible light at the processing point is detected, it is possible to suppress the simplification of the structure and the increase in size and manufacturing cost of the laser processing apparatus.

According to the laser processing method and laser processing apparatus according to the present invention, when the work material is cut by irradiating the laser beam, the inspection laser beam is irradiated from the surface side of the work material and based on the dross detection light. Since the dross adhesion status on the back surface side of the cutting groove is determined, the dross adhesion status on the back surface side of the cutting groove can be easily and efficiently determined.
As a result, it is possible to efficiently suppress cutting defects caused by dross adhering to the back surface side of the material to be processed.

It is a conceptual diagram explaining an example of the schematic structure of the laser processing apparatus which concerns on 1st Embodiment of this invention. It is a conceptual diagram explaining an example of the cutting path, the cutting section and the inspection section when cutting a product from a work material by the laser processing apparatus which concerns on 1st Embodiment of this invention. It is a flowchart explaining an example of operation of the laser processing apparatus which concerns on 1st Embodiment of this invention. It is a conceptual diagram explaining an example of the cutting groove formation by the laser processing apparatus which concerns on 1st Embodiment of this invention. It is a conceptual diagram explaining an example of the adhesion state inspection of the dross adhering to the cutting groove by the laser processing apparatus which concerns on 1st Embodiment of this invention. It is a conceptual diagram explaining an outline example of the method of determining the dross adhesion state by the laser processing apparatus which concerns on 1st Embodiment of this invention. It is a conceptual diagram explaining an example of the schematic structure of the laser processing apparatus which concerns on 2nd Embodiment of this invention.

The laser processing apparatus according to the present invention includes, for example, a laser processing head that injects an assist gas from a nozzle hole and irradiates a cutting laser beam, a cutting laser beam irradiating unit that irradiates a cutting laser beam, and a cutting laser. It is emitted from a cutting laser oscillator that outputs a beam, an inspection laser beam irradiation unit that irradiates an inspection laser beam, an inspection laser oscillator that outputs an inspection laser beam, and a dross heated by the inspection laser beam. A dross detection light detector that detects dross detection light that includes at least one of the dross radiation and the reflected light reflected by the dross, and an assist gas supply means that supplies the assist gas to the laser processing head. A laser processing head moving means for moving the laser processing head and a control unit are provided, and the control unit irradiates a cutting laser beam from the surface side of the material to be processed to form a cutting groove, and forms a cutting groove in the cutting groove. It is configured to irradiate the inspection laser beam from the front surface side while moving along the line, and to determine the dross adhesion state on the back surface side of the cutting groove based on the dross detection light detected by the dross detection light detection unit.

<First Embodiment>
Hereinafter, the laser processing apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 6.
FIG. 1 is a conceptual diagram illustrating a schematic configuration of a laser machining apparatus according to a first embodiment of the present invention, and FIG. 2 is a cutting path, a cutting section, and an inspection when a product is cut out from a work material by the laser machining apparatus. It is a conceptual diagram explaining an example of a use section, and FIG. 3 is a flowchart explaining an example of operation of the laser processing apparatus which concerns on 1st Embodiment. In the figure, reference numeral 100 indicates a laser processing apparatus, reference numeral 10 indicates a laser processing head, reference numeral 10A indicates a laser nozzle, reference numeral 20 indicates a laser oscillator, and reference numeral W indicates a steel plate (work material).

As shown in FIG. 1, the laser processing apparatus 100 according to the first embodiment includes, for example, a laser processing head 10, a laser nozzle 10A, a laser beam irradiation unit 11, and a photodiode (dross detection light detection unit) 12. , Collimating lens 13, condensing lens 14, laser oscillator 20, assist gas supply unit (assist gas supply means) 30 that supplies assist gas G to the laser processing head 10, and servo control that moves the laser processing head 10. A device (laser processing head moving means) 40 and a control unit 50 are provided, and the steel plate (processed material) W is irradiated with a cutting laser beam LA from the surface side from the nozzle hole 10H of the laser processing head 10 to the steel plate W. The cutting groove H is formed.

As shown in FIG. 1, the laser processing head 10 has, for example, a laser nozzle 10A arranged on the tip side.
Further, a laser beam irradiation unit 11, a photodiode (dross detection light detection unit) 12, and a condenser lens 14 are arranged inside the laser processing head 10.
The laser nozzle 10A is formed of a tubular body having a conical tip side and a cylindrical base end side, and a nozzle hole 10H is formed at the tip.

Further, an assist gas supply path (not shown) is formed around the optical path of the cutting laser beam LA, and the cutting laser beam LA is irradiated from the nozzle hole 10H and the assist gas G is injected. ..
Further, in this embodiment, the inspection laser beam LB is also irradiated from the nozzle hole 10H.

In this embodiment, the laser beam irradiation unit 11 is composed of, for example, a fiber laser, and is connected to the laser oscillator 20 and has a cutting laser beam LA and an inspection laser beam LB according to the output of the laser oscillator 20. It is configured to irradiate.
Then, the cutting laser beam LA and the inspection laser beam LB irradiated from the laser beam irradiation unit 11 pass through the collimating lens 13 and the condensing lens 14 and are irradiated from the nozzle hole 10H toward the steel plate W. It has become.

When the laser beam LA is irradiated from the laser processing head 10 toward the steel plate (work material) W, the steel plate W is melted to generate a melt, and the generated melt forms a molten pool. This melt is oxidized and burned by the assist gas G and discharged from the molten pool by the jet of the assist gas G to form a cutting groove.

A plurality of photodiodes (dross detection light detection units) 12 are arranged inside the laser processing head 10, and are configured to detect a cutting laser beam LA, an inspection laser beam LB, and a dross detection light LC. Further, the photodiode 12 is connected to the control unit 50 by a signal cable 52, and the detected dross detection optical signal is sent to the control unit 50 via the cable 52.
In this embodiment, the dross detection light LC is, for example, dross synchrotron radiation composed of visible light emitted by the red-heated dross irradiated with the inspection laser beam LB.

The laser oscillator 20 can be switched to an output corresponding to the cutting laser beam LA and the inspection laser beam LB according to the instruction of the control unit 50.

The assist gas supply unit 30 includes, for example, a nitrogen (inert gas) supply source, an oxygen (flammable gas) supply source, and an assist gas control unit, and the nitrogen supplied from the nitrogen supply source and the oxygen supply source. And oxygen are mixed by the assist gas control unit and the pressure is adjusted to generate the assist gas G. Further, the assist gas supply unit 30 supplies the assist gas G to the laser processing head 10 based on the instruction of the control unit 50.

The servo controller 40 uses the laser processing head 10 on which the laser nozzle 10A is mounted in the X-axis direction (traveling direction), the Y-axis direction (traverse direction), and the Z-axis direction (height direction) based on the instruction from the control unit 50. ), The laser processing head 10 is moved to a predetermined position on the steel plate W, and the laser processing head 10 is moved on the platen according to the cutting path and the inspection section.

The control unit 50 is connected to the laser oscillator 20, the assist gas supply unit 30, and the servo controller 40 via, for example, a signal cable 51, and the cutting path, cutting section, inspection path, etc. input from the input unit (not shown). It is configured to output a signal to the servo controller 40 based on NC data such as an inspection section to instruct the movement path of the laser processing head 10 and to instruct the laser oscillator 20 and the assist gas supply unit 30.

Further, the control unit 50 is connected to the photodiode (dross detection light detection unit) 12 via the signal cable 52, and the synchrotron radiation (for example,) emitted by the dross heated by the inspection laser beam input from the photodiode 12. , Visible light), it is configured to determine the adhesion state of the dross in the cutting groove H.

In this embodiment, the cutting laser beam LA is, for example, a steel plate having a thickness of 12.0 mm, a peak output of 3.0 to 6.0 Kw, a frequency of 1000 Hz, a duty of 70 to 100%, and a speed of 900 to 2250 (mm / min). ), The steel plate having a plate thickness of 22.0 mm has a peak output of 4.2 to 4.5 Kw, a frequency of 10000 Hz, a duty of 80%, and a speed of 700 to 750 (mm / min).
Further, in the case of a steel plate having a plate thickness of 12.0 mm and 22.0 mm, the assist gas pressure is 0.35 (kgf / cm ² ) and the total flow rate of the shield gas is 100 (L / min).

The inspection laser beam LB is configured so as not to damage the work material on which the cutting groove is formed, adjusts the focus so that the dross adhesion portion to be detected is irradiated, and suppresses the oxidation reaction with a high energy density ( That is, it is necessary to reduce the oxygen concentration of the shield gas), for example, the peak output is 2.0 kW, the frequency is 100 Hz, the duty is 10%, and the speed is 600 (mm / min), which is smaller than the cutting laser beam LA. It is said that. The assist gas pressure at this time is set to 0.35 (kgf / cm ² ) and the total flow rate of the shield gas is 100 (L / min).

Hereinafter, with reference to FIG. 2, a cutting path, a cutting section, and an inspection section in which the laser processing head 10 moves when cutting out a product will be described.

Here, the cutting path is a path that the laser processing head 10 moves when forming the cutting groove H.
Further, the cutting section refers to a section from the starting point at which the laser processing head 10 starts moving to the ending point at which the movement is temporarily stopped when the cutting groove H is formed in the cutting path.

The inspection path is a path that the laser machining head 10 moves when inspecting the cutting groove H.
The inspection section is a section for inspecting the cutting groove H, and means a section composed of the entire range or a part of the cutting section formed before the cutting groove H.

In this embodiment, the moving direction of the laser machining head 10 in the inspection section is set to move in the arrow T2 direction opposite to the moving direction of the laser machining head 10 when forming the cutting groove H.
It should be noted that whether the moving direction of the laser machining head 10 in the inspection path is opposite to or the same direction as the moving direction of the laser machining head 10 when forming the cutting groove H can be arbitrarily set.

In the first embodiment, as shown in FIG. 2, the product ST cut out from the steel plate W is set to be substantially rectangular. In FIG. 2, the cutting path is shown by, for example, a path from P1 to P10.

Further, P1 to P2, P3 to P4, P5 to P6, P7 to P8, and P9 to P10 shown by solid lines in FIG. 2 indicate cutting sections, and P1, P3, P5, and P7 indicate the starting point of the cutting section. P2, P4, P6, P8, and P10 indicate the end points of the cutting section.

Further, P2 to P3, P4 to P5, P6 to P7, and P8 to P9 shown by broken lines in FIG. 2 indicate inspection sections, respectively, and P2, P4, P6, and P8 indicate the start points of the inspection sections, and P3, P5, P7 and P9 indicate the end points of the inspection section. In this embodiment, the inspection after forming the cutting groove H in the cutting sections P9 to P10 is not performed.

In this embodiment, as shown in FIG. 2, the inspection section is not set over the entire length of the cutting section, but is composed of a part of the cutting section in which the adhesion of dross is easily detected, and the cutting sections overlap. The part is cut twice. The inspection section may be set over the entire length of the cutting section, or may be configured not to be cut twice by, for example, matching P3 with P2.

Hereinafter, with reference to FIGS. 3 to 6, an operation procedure of the laser cutting device according to the first embodiment, formation of a cutting groove, and an example of an inspection of the state of adhesion of dross adhering to the cutting groove will be described. FIG. 3 is a flowchart illustrating an example of the operation of the laser processing apparatus according to the first embodiment, in which a cutting groove is formed for one cutting section and then the inspection is completed for the inspection section set in the cutting section. Shows the operation of. Further, FIG. 4 is a conceptual diagram illustrating an example of forming a cutting groove by the laser processing apparatus according to the first embodiment, and FIG. 5 is an example of inspecting the adhesion state of dross adhering to the cutting groove by the laser processing apparatus. It is a conceptual diagram.

Hereinafter, the operation procedure of the laser cutting device 100 will be described according to the flowchart shown in FIG.
(1) First, NC data information regarding a cutting section (start point, end point) constituting a cutting path of a work material and an inspection section (start point, end point) in each cutting section is acquired (S1).
(2) Next, the cutting conditions (for example, the output of the laser oscillator when irradiating the cutting laser beam) are acquired and set (S2).
(3) Next, the laser head is moved to the start point of the cutting section (S3).
(4) Next, the laser oscillator and the assist gas supply device are operated to irradiate the cutting laser beam from the laser beam irradiation unit, and the servo controller 40 is operated to move the laser head along the cutting path (). S4).

As a result, as shown in FIG. 4, the laser nozzle 10A irradiates the laser beam LA from the laser beam irradiating unit 11 while moving the cutting section in the direction of the arrow T1 and injects the assist gas into the cutting groove H in the steel plate W. To form. At this time, the dross D adheres to the cutting groove H.
(5) When the end point of the cutting section is reached, the irradiation of the cutting laser beam and the supply of the assist gas are stopped, and the servo controller is stopped to stop the movement of the laser processing head (S5).
(6) Next, the cutting condition is changed to the inspection condition so that the inspection laser beam is irradiated from the laser beam irradiation unit (S6).
(7) Next, the laser head is moved to the start point of the inspection section (S7).
(8) Next, while operating the servo controller 40 to move the laser processing head over the inspection section in the cutting groove formed in S7, the laser oscillator is operated to apply the assist gas from the laser beam irradiation unit toward the cutting groove. The dross detection light is detected by a photodiode (dross detection light detection unit) by injecting and irradiating the inspection laser beam (S8).
In this embodiment, as shown in FIG. 2, for example, the movement of the laser nozzle in the inspection section is in the opposite direction to that when the cutting groove is formed.

As shown in FIG. 5, the laser processing head 10 moves the inspection laser beam LB in the direction of the arrow T2 to detect the dross detection light LC emitted from the dross by irradiating the inspection laser beam LB. It is irradiated and the dross detection light LC is detected by the photodiode (dross detection light detection unit) 12.
(9) When the end point of the inspection section is reached, the laser oscillator is stopped to stop the irradiation of the laser beam for inspection, and the servo controller is stopped to stop the movement of the laser machining head 10 (S9).
(10) It is determined whether or not the dross adhesion state on the back surface of the cutting groove is within the allowable range (S10).
Whether or not the dross adhesion state is within the allowable range is determined by comparing the intensity of the detected dross detection light with a preset threshold value, and for example, calculating the ratio of the dross detection light exceeding the threshold value at a preset inspection length. To do. When the dross adhesion status on the back surface of the cutting groove is within the permissible range (S10: Yes), the process proceeds to S11, and when the dross adhesion status on the back surface of the cutting groove is out of the permissible range (S10: No), for example, an alarm is issued. Output and interrupt disconnection.

Hereinafter, an outline example of a method for determining the dross adhesion state by the laser processing apparatus will be described with reference to FIG. FIG. 6 is a conceptual diagram illustrating an outline example of a method for determining a dross adhesion state by the laser processing apparatus according to the first embodiment. In FIG. 6, the horizontal axis represents the length of the inspection section (inspection length) from P _{n-1 to} P _n , the vertical axis represents the intensity of the dross detection light, and the symbol V1 represents the threshold value regarding the intensity of the dross detection light. Shown. The symbol V is the intensity of the dross detection light in the inspection section.
As shown in FIG. 6, the intensity V of the dross detection light changes according to the position of the inspection section, and the total length of the portion (shaded portion) where the intensity V of the dross detection light exceeds the threshold value V1 is calculated. Divide by the length dimension of the inspection section P _{n-1 to} P _n to calculate the ratio of the dross detection light exceeding the threshold value at the preset inspection length.
It should be noted that this is an example of a determination method for determining the adhesion state of dross, and the determination method can be arbitrarily set.

(11) It is determined whether or not there is a remaining cutting section, that is, whether or not cutting grooves are formed in all the cutting sections (S11).
If there is a remaining cutting section (S11: Yes), the process proceeds to S3, and if there is no remaining cutting section (S11: No), the flow ends.
S1 to S11 are executed until the cutting path is cut.

According to the laser processing apparatus 100 according to the first embodiment, after the material to be processed is irradiated with a cutting laser beam to form a cutting groove H, the formed cutting groove H is irradiated with an inspection laser beam LB and reddened. Since the dross detection light LC radiated from the dross is detected and the dross D adhesion status on the back surface side of the cutting groove H is determined based on the dross detection light LC, the dross D adhesion status on the back surface side of the cutting groove H is determined. Can be easily and efficiently determined.
As a result, it is possible to efficiently suppress cutting defects caused by the dross D adhering to the back surface side of the material to be processed.

According to the laser processing apparatus 100 according to the first embodiment, since the adhesion state of the dross D on the back surface side of the cutting groove is determined by the ratio of the intensity exceeding the threshold value in the dross detection light LC, the dross D on the back surface side of the cutting groove H is determined. It is possible to stably judge the adhesion state of.

According to the laser processing apparatus 100 according to the first embodiment, the output of the oscillator 20 used for the output of the cutting laser beam is reduced to irradiate the laser beam for inspection, and the photo is arranged inside the laser processing head 10. Since the diode (dross detection light detection unit) 12 is configured to detect the dross detection light LC radiated from the dross, the structure is simplified, the size of the laser processing apparatus 100 is increased, and the manufacturing cost is increased. Can be suppressed.

<Second Embodiment>
Hereinafter, the laser processing apparatus according to the second embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a conceptual diagram illustrating a schematic configuration of a laser processing apparatus according to a second embodiment of the present invention. In FIG. 7, reference numeral 200 is a laser processing apparatus, reference numeral 10 is a laser processing head 10, and reference numeral 12A is Indicates a photodiode (dross detection light detection unit), and reference numeral 60 indicates a bending mirror (specific wavelength band reflection mirror).

As shown in FIG. 7, the laser processing apparatus 200 includes, for example, a laser processing head 10, a laser beam irradiation unit 11, a photodiode (dross detection light detection unit) 12A, a collimating lens 13, and a condenser lens 14. , A laser oscillator 20, an assist gas supply unit (assist gas supply means) 30, a servo controller (nozzle moving means) 40, a control unit 50, and a bending mirror (specific wavelength band reflection mirror) 60. A cutting groove H is formed in the steel plate W by irradiating the steel plate (work material) W with a cutting laser beam LA from the surface side through the nozzle hole 10H of the processing head 10.

As shown in FIG. 7, the laser nozzle 10A has a nozzle hole 10H formed at the tip thereof, and a condenser lens 14 is arranged inside the laser processing head 10.
Further, a bending mirror 60 is arranged above the laser processing head 10 at an angle of 45 ° with respect to the axis of the laser nozzle 10A, and a photodiode (dross detection light) is arranged behind the bending mirror 60 (opposite to the nozzle hole 10H). Detection unit) 12A is arranged.

The laser beam irradiation unit 11 is arranged so that the optical axis is tilted 90 ° with respect to the axis of the laser nozzle 10A (90 ° with respect to the bending mirror 60), and the irradiated cutting laser beam LA and the inspection laser are arranged. The beam LB is reflected by the bending mirror (specific wavelength band reflection mirror) 60 and guided to the nozzle hole 10H via the condenser lens 14, and is irradiated from the nozzle hole 10H to form a cutting groove H in the steel plate W. Has been done.

Further, in the inspection laser beam LB output by the laser beam irradiation unit 11, the dross detection light (for example, visible light) emitted by red heat of the dross formed on the back surface side of the cutting groove H passes through the nozzle hole 10H. It is incident on the laser processing head 10, passes through the bending mirror 60, and is detected by the photodiode (optical sensor) 12A. Others are the same as those in the first embodiment, so the same reference numerals are given and the description thereof will be omitted.

According to the laser processing apparatus 200 according to the second embodiment, the bending mirror 60 is arranged between the cutting laser beam irradiation unit 11 and the nozzle hole 10H to output the cutting laser beam LA and the cutting laser beam LA. The inspection laser beam LB irradiated with a reduced output of the oscillator 20 used is reflected by the bending mirror 60 and irradiated from the nozzle hole 10H, and the photodiode 12A arranged behind the bending mirror 60 passes through the bending mirror 60. Since the visible light at the processing point is detected by the dross detection light, it is possible to simplify the structure and suppress the increase in size and the manufacturing cost of the laser processing apparatus 200.

Further, according to the laser processing apparatus 200 according to the second embodiment, since the photodiode 12A can be arranged directly above the processing point, the detection accuracy can be improved and false detection can be suppressed.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

For example, in the above embodiment, the intensity of the detected dross detection light is compared with a preset threshold value, and dross adheres depending on whether the ratio of the dross detection light exceeding the threshold value at the preset inspection length is within the allowable range. The case of determining the situation has been described, but for example, it is based on the total reflection amount of the dross detection light obtained by integrating the intensity of the dross detection light, the length of the dross detection light exceeding the threshold value, the mode of the dross detection light, and the like. The dross adhesion status may be determined, and the dross adhesion status can be arbitrarily set.

Further, in the above embodiment, the case where the cutting laser beam and the inspection laser beam are irradiated by switching the output of the laser oscillator 20 has been described, but the cutting laser beam and the inspection laser beam are different laser oscillators. It may be configured by.

Further, in the above embodiment, the inspection laser beam LB output by the laser beam irradiation unit 11 is irradiated from the nozzle hole 10H of the laser nozzle 10A, and the dross emitted from the dross red-heated by the inspection laser beam LB. The case where the detection light (for example, visible light) LC is detected by the photodiode (optical sensor) 12 arranged in the laser processing head 10 via the nozzle hole 10H has been described, but the irradiation unit of the cutting laser beam LA has been described. Separately, the laser beam LB for inspection is irradiated from the laser beam irradiating unit 1 provided outside the laser processing head 10, and the dross detection light LC is received by the optical sensor arranged outside the laser processing head 10. May be.

Further, in the above embodiment, the case where the dross detection light is dross radiated light (visible light) LC emitted from the dross heated by the inspection laser beam LB has been described, but instead of the dross radiated light, , The dross detection light including the reflected light of the inspection laser beam LB, the dross radiated light and the reflected light may be used, or the dross radiated light such as infrared rays may be used.

Further, in the above embodiment, for example, the case where the laser oscillator 20 is a fiber laser has been described, but the type of the laser oscillator 20, the type of the irradiation beam (continuous, pulse), the output of the laser beam, the frequency, the duty, etc. May be set arbitrarily.

For example, in the above embodiment, the case where the work material is the steel plate W has been described, but it can be applied to various metal plates in which dross occurs during cutting.
Further, the type of assist gas G can be arbitrarily set.

According to the laser processing method and laser processing apparatus according to the present invention, when cutting a work material by irradiating a laser beam, cutting defects occur due to dross adhering to the back surface side of the work material. Can be used industrially because it can be efficiently suppressed.

LA Laser beam for cutting LB Laser beam for inspection LC Dross detection light D Dross (adhered dross)
G Assist gas W Steel plate (work material)
10 Laser processing head 10A Laser nozzle 10H Nozzle hole 11 Laser beam irradiation unit 12, 12A photodiode (dross detection photodetection unit)
20 Laser oscillator 30 Assist gas supply unit (Assist gas supply means)
40 Servo controller (laser machining head moving means)
50 Control unit 60 Specific wavelength band reflection mirror 100 Laser processing device

Claims (6)

A laser processing method in which a work material is irradiated with a laser beam to cut the work material.
A cutting laser beam is irradiated from the surface side of the work material to form a cutting groove, and the inspection laser beam is irradiated from the surface side while moving along the cutting groove, and the inspection laser beam is used. The dross radiated light emitted from the heated dross and the inspection laser beam detect the dross detection light including at least one of the reflected light reflected by the dross, and the back side of the cutting groove is based on the dross detection light. A laser processing method characterized in determining the state of adhesion of dross. The laser processing method according to claim 1.
A laser processing method characterized in that the dross adhesion state on the back surface side of the cutting groove is determined based on the ratio at which the intensity of the dross detection light exceeds a threshold value. A laser processing device that irradiates a work material with a laser beam to cut the work material.
A laser processing head that injects assist gas from the nozzle hole and irradiates a cutting laser beam,
The cutting laser beam irradiation unit that irradiates the cutting laser beam,
A cutting laser oscillator that outputs the cutting laser beam and
An inspection laser beam irradiation unit that irradiates an inspection laser beam,
An inspection laser oscillator that outputs the inspection laser beam and
A dross detection light detection unit that detects dross detection light including at least one of dross synchrotron radiation emitted from the dross heated by the inspection laser beam and reflected light reflected by the dross by the inspection laser beam. ,
An assist gas supply means for supplying the assist gas to the laser processing head and
A laser machining head moving means for moving the laser machining head,
Control unit and
With
The control unit
A cutting laser beam is irradiated from the surface side of the work material to form a cutting groove, and the inspection laser beam is irradiated from the surface side while moving along the cutting groove, and the dross detection light detection unit is used. A laser processing apparatus characterized in that it is configured to determine the dross adhesion state on the back surface side of the cutting groove based on the dross detection light detected by. The laser processing apparatus according to claim 3.
The control unit
A laser processing apparatus characterized in that the dross adhesion state on the back surface side of the cutting groove is determined based on the ratio of the intensity of the dross detection light exceeding the threshold value. The laser processing apparatus according to claim 3 or 4.
The output of the oscillator used for the output of the cutting laser beam is reduced to irradiate the laser beam for inspection, and the dross detection light is detected by the dross detection light detection unit arranged inside the laser processing head. Laser processing equipment characterized by being The laser processing apparatus according to claim 3 or 4.
A specific wavelength band reflection mirror that reflects the wavelength band of the cutting laser beam and transmits the dross detection light is arranged between the cutting laser beam irradiation unit and the nozzle hole.
The inspection laser beam irradiated by reducing the output of the cutting laser beam and the oscillator used for the output of the cutting laser beam is reflected by the specific wavelength band reflection mirror and irradiated from the nozzle hole, and at the same time, the specific wavelength A laser processing apparatus characterized in that it is configured to detect visible light at a processing point by dross detection light transmitted through the specific wavelength band reflection mirror by an optical sensor arranged behind the band reflection mirror.

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