JP2011115806A - Laser processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser processing apparatus capable of executing centering work of laser beam in a short period of time without depending on skill degree of an operator. <P>SOLUTION: The laser processing apparatus is configured of a laser oscillator 1 for generating the laser beam 2, a processing lens 4 for condensing the laser beam 2 on a workpiece W, a processing nozzle 11 for passing the condensed laser beam 2 and supplying assist gas toward the workpiece W, a processing head 5 for supporting the processing lens 4 and the processing nozzle 11, a light sensor 6 for detecting spatial distribution of light emitted from the irradiation part of the workpiece W during the irradiation of the laser beam 2, and a signal processing device 9 for measuring the position of the laser beam 2 to the center of the nozzle based on a signal from the light sensors 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus having a laser beam centering function.

  A conventional laser processing apparatus (for example, Patent Document 1) includes a laser oscillator that oscillates a laser beam, and a processing head that supplies an assist gas by irradiating the workpiece with the laser beam oscillated from the laser oscillator. And an optical sensor for detecting light generated from a processed portion of the workpiece by irradiation with the laser beam, and controls the laser oscillator, and controls the laser oscillator signal intensity of the workpiece by the optical sensor signal intensity detected by the optical sensor. It is configured so that the processing status can be monitored.

  In another laser processing apparatus (for example, Patent Document 2), the anisotropy due to the cutting direction of the signal at the time of cutting processing is measured by a photodiode, and the nozzle does not appear even if the cutting direction changes. Have moved.

Japanese Patent Laying-Open No. 2005-254314 (page 8, FIG. 1) Japanese Patent Laid-Open No. 10-24966 (page 8, FIG. 1)

  When processing is performed with a laser processing apparatus, a preparation step called centering is generally performed. This is a step of adjusting the position of the processing lens and the position of the processing nozzle so that the laser beam passes through the center of the processing nozzle. At that time, a hole is made in a thin acrylic plate or tape with a laser beam, and the positions of the lens and the nozzle are adjusted while judging the shape of the processed hole and the flow of gas by visual observation of the operator.

  However, visual judgment is difficult unless it is an expert, and it depends greatly on the operator's experience, such as how much adjustment should be performed at the center of the nozzle, and generally requires work that requires a lot of time. Become.

  The objective of this invention is providing the laser processing apparatus which can implement the centering operation | work of a laser beam in a short time, without depending on the skill level of an operator.

In order to achieve the above object, a laser processing apparatus according to the present invention includes a laser oscillator that generates laser light,
A condensing optical system for condensing the laser beam on the workpiece;
A focused laser beam passes, and a nozzle for supplying gas toward the workpiece;
A processing head for supporting the condensing optical system and the nozzle;
A light detection unit for detecting a spatial distribution of light emitted from the irradiated portion of the workpiece when irradiated with laser light; and
And a signal processing unit for measuring the position of the laser beam with respect to the center of the nozzle based on a signal from the light detection unit.

  According to the present invention, the laser beam centering operation can be performed in a short time without depending on the proficiency level of the operator.

It is a block diagram which shows Embodiment 1 of this invention. It is a top view which shows the example of arrangement | positioning of an optical sensor. FIG. 3A is a plan view showing the arrangement of the optical sensors on the XY plane, and FIGS. 3B to 3D are graphs showing signal examples in a state where the laser light 2 passes through the center of the nozzle. It is. FIG. 4A is a plan view showing the arrangement of the photosensors on the XY plane, and FIGS. 4B to 4D are graphs showing signal examples in a state where the laser beam 2 deviates from the nozzle center. is there. It is a block diagram which shows Embodiment 2 of this invention. It is a block diagram which shows Embodiment 3 of this invention. It is a block diagram which shows Embodiment 4 of this invention. It is a block diagram which shows Embodiment 5 of this invention.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing Embodiment 1 of the present invention. The laser processing apparatus includes a laser oscillator 1, a reflection mirror 3, a processing lens 4, a processing head 5, a processing nozzle 11, and the like.

  The laser oscillator 1 is constituted by a carbon dioxide laser, an excimer laser, or the like, and generates a laser beam 2 having a wavelength and power suitable for cutting, drilling, welding and the like of the workpiece W that is a workpiece.

  The reflection mirror 3 has a function of reflecting the laser beam 2 from the laser oscillator 1 and introducing it into the machining head 5. Two or more mirrors may be used or omitted as necessary. Is possible.

  The processing lens 4 is a condensing optical system that condenses the laser light 2 introduced into the processing head 5, and forms a desired light spot at a processing portion of the workpiece W.

  The processing nozzle 11 is a hollow cylindrical member, and has a function of supplying the assist gas toward the workpiece W while allowing the laser beam condensed by the processing lens 4 to pass therethrough. As the assist gas, oxygen, air, nitrogen, argon or the like is generally used, and plays a role of eliminating evaporated gas and preventing dross adhesion.

  The processing head 5 is a hollow cylindrical member that supports the processing lens 4, the processing nozzle 11, and the like, and is connected to an assist gas supply circuit (not shown).

  In the present embodiment, the laser processing apparatus further includes an optical sensor 6, an amplifier 7, a numerical control device 8, a signal processing device 9, and an actuator 10.

  The optical sensor 6 is for detecting the spatial distribution of light emitted from the irradiated portion of the work W when the laser beam 2 is irradiated. The light receiving part of the optical sensor 6 is located inside the machining head 5, and the light emitted from the irradiated part of the workpiece W passes through the machining nozzle 11 and the machining lens 4 and directly to the light receiving part of the optical sensor 6. Or it is configured to reach indirectly. For example, as shown in FIG. 2, three lights are arranged at equal intervals of 120 ° around the optical axis of the laser beam 2 on the circumference having a predetermined radius in the XY plane perpendicular to the optical axis of the laser beam 2. A sensor 6 is arranged.

  The amplifier 7 amplifies the signal from the optical sensor 6. The signal processing device 9 has a function of measuring the position of the laser light 2 with respect to the nozzle center of the processing nozzle 11 based on a signal from the optical sensor 6.

  The numerical control device 8 has a function of setting processing conditions such as irradiation power, irradiation timing and the like by signal transmission with the laser oscillator 1 and the signal processing device 9 or by a command from an external computer or the like.

  The actuator 10 is provided in the processing head 5 and has a function of adjusting the XY position of the processing lens 4 with reference to the processing head 5. Based on the measurement result of the laser beam 2, the signal processing device 9 controls the actuator 10 so that the laser beam 2 passes through the center of the nozzle.

  Next, the operation will be described. The laser beam 2 output from the laser oscillator 1 is reflected by the reflection mirror 3, condensed by the processing lens 4 in the processing head 5, and irradiated on the processing portion of the workpiece W. At this time, the optical sensor 6 detects the intensity of light generated from the processed portion. A signal from the optical sensor 6 is amplified by an amplifier and input to the signal processing device 9.

  The signal processing device 9 stores in advance, as a reference value, the ratio of the signal intensity of each optical sensor 6 in the state in which the laser light 2 has passed through the center of the nozzle, that is, in the centering state. Therefore, the displacement amount and the displacement direction of the laser beam 2 with respect to the nozzle center can be calculated by comparing the signal intensity ratio at the time of measurement with the reference value. Then, the signal processing device 9 can set the laser light 2 to pass through the center of the processing nozzle 11 by adjusting the XY position of the processing lens 4 by the actuator 10 using the calculation result.

  FIG. 3A is a plan view showing the arrangement of the optical sensors on the XY plane, and FIGS. 3B to 3D show the state in which the laser light 2 passes through the center of the nozzle, that is, the centering state. It is a graph which shows the example of a signal. Here, an example will be described in which three optical sensors 6 a to 6 c are arranged at equal intervals of 120 ° around the optical axis of the laser light 2.

  In the centering state, the spatial distribution of the light emitted from the irradiated portion of the workpiece W when the laser beam 2 is irradiated is symmetric with respect to the optical axis of the laser beam 2. Therefore, the light intensities received by the optical sensors 6a to 6c are substantially equal to each other, and the signal intensity ratio Ia: Ib: Ic = 1: 1: 1 is an ideal reference value. In practice, the reference value is determined in consideration of errors such as noise and sensor sensitivity variations. Such a reference value is preferably set each time the processing nozzle 11 or the processing lens 4 is replaced or the workpiece W is changed.

  FIG. 4A is a plan view showing the arrangement of the photosensors on the XY plane, and FIGS. 4B to 4D are graphs showing signal examples in a state where the laser beam 2 deviates from the nozzle center. is there. When the centering is incomplete, the spatial distribution of the light emitted from the irradiated portion of the workpiece W when the laser beam 2 is irradiated becomes asymmetric with respect to the optical axis of the laser beam 2. Therefore, the light intensity received by each of the optical sensors 6a to 6c also deviates from the reference value. For example, as shown in FIG. 4A, when the laser beam 2 is closest to the optical sensor 6b and is farthest from the optical sensor 6c, the signal intensity shows a relationship of Ia <Ic <Ib.

  Therefore, by calculating in advance the relationship between the signal intensity ratio Ia: Ib: Ic and the center deviation of the laser beam 2, the displacement amount and the displacement direction of the laser beam 2 can be determined from the actual signal intensity ratio. .

  Here, in Patent Document 2, the light receiving luminance is detected while cutting a plate-like workpiece along a rectangular path in a state where one photodiode is installed in the head. At this time, the output signal of the photodiode is analyzed for anisotropy depending on the cutting direction, and the nozzle or bend mirror is driven in a direction in which the anisotropy disappears. However, since the cutting process is performed without performing the centering, the probability of the processing failure increases, and there is a possibility that accurate adjustment cannot be performed.

  On the other hand, according to the present invention, the processing at the time of performing the centering operation can be performed by one-pulse irradiation of laser light. Also, by calculating using the intensity ratio instead of anisotropy, even if the position of the laser beam deviates from the center of the processing nozzle due to the collision of the processing head at the time of cutting, it is automatically centered each time. It is possible to make adjustments.

  The initial setting of the reference value of the signal intensity ratio in the centering state is preferably performed by adjustment at the shipping stage so as not to be affected by variations in the sensitivity of the optical sensor and variations in the amount of received light due to attachment.

  When the actuator 10 is omitted, the displacement amount and the displacement direction of the laser light 2 calculated by the signal processing device 9 are displayed on a display or the like, and the operator manually adjusts the XY position of the processing lens 4 Even so, the working time can be greatly shortened as compared with the centering process visually performed by the operator. At this time, measurement can be performed with high accuracy by adjusting the focal position of the laser beam 2.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing Embodiment 2 of the present invention. The laser processing apparatus according to the present embodiment has the same configuration as that of the first embodiment, but adjusts the XY position of the processing nozzle 11 relative to the processing head 5 instead of the actuator that adjusts the XY position of the processing lens 4. The actuator 10 is provided.

  This operation will be described. The laser beam 2 output from the laser oscillator 1 is reflected by the reflection mirror 3, condensed by the processing lens 4 in the processing head 5, and irradiated on the processing portion of the workpiece W. At this time, the optical sensor 6 detects the intensity of light generated from the processed portion. A signal from the optical sensor 6 is amplified by an amplifier and input to the signal processing device 9.

  The signal processing device 9 stores in advance, as a reference value, the ratio of the signal intensity of each optical sensor 6 in the state in which the laser light 2 has passed through the center of the nozzle, that is, in the centering state. Therefore, the displacement amount and the displacement direction of the laser beam 2 with respect to the nozzle center can be calculated by comparing the signal intensity ratio at the time of measurement with the reference value. The signal processing device 9 can set the laser light 2 to pass through the center of the processing nozzle 11 by adjusting the XY position of the processing nozzle 11 by the actuator 10 using the calculation result.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing Embodiment 3 of the present invention. The laser processing apparatus according to the present embodiment has the same configuration as that of the first embodiment, but an actuator 10 for adjusting the orientation of the reflection mirror 3 is provided instead of the actuator for adjusting the XY position of the processing lens 4. Thus, the optical path of the laser light 2 when passing through the processing nozzle 11 is configured to be adjustable in the XY directions.

  This operation will be described. The laser beam 2 output from the laser oscillator 1 is reflected by the reflection mirror 3, condensed by the processing lens 4 in the processing head 5, and irradiated on the processing portion of the workpiece W. At this time, the optical sensor 6 detects the intensity of light generated from the processed portion. A signal from the optical sensor 6 is amplified by an amplifier and input to the signal processing device 9.

  The signal processing device 9 stores in advance, as a reference value, the ratio of the signal intensity of each optical sensor 6 in the state in which the laser light 2 has passed through the center of the nozzle, that is, in the centering state. Therefore, the displacement amount and the displacement direction of the laser beam 2 with respect to the nozzle center can be calculated by comparing the signal intensity ratio at the time of measurement with the reference value. The signal processing device 9 can be set so that the laser light 2 passes through the center of the processing nozzle 11 by adjusting the direction of the reflection mirror 3 by the actuator 10 using the calculation result.

Embodiment 4 FIG.
FIG. 7 is a block diagram showing Embodiment 4 of the present invention. In this embodiment, when the actuator 10 for adjusting the XY position of the processing lens 4 is provided as in the first embodiment, the XY position of the processing nozzle 11 with respect to the processing head 5 is adjusted as in the second embodiment. When the actuator 10 is provided, the actuator 10 for adjusting the direction of the reflection mirror 3 is provided as in the third embodiment, and the optical path of the laser light 2 when passing through the processing nozzle 11 can be adjusted in the XY directions. Applicable to any of the cases.

  In the present embodiment, the four optical sensors 6 are arranged at equal intervals of 90 ° around the optical axis of the laser light 2 on the circumference having a predetermined radius in the XY plane perpendicular to the optical axis of the laser light 2. Be placed. That is, the optical axis of the laser beam 2 is the origin (0, 0) of the XY coordinates, the radius of the circumference is r, and the coordinates (r, 0), (−r, 0), (0, r), (0 , -R), the optical sensors 6a to 6d are respectively arranged.

  With such an arrangement, the adjustment direction (X direction and Y direction) of the actuator 10 and the arrangement direction (X direction and Y direction) of the optical sensors 6 coincide with each other, and high-precision centering adjustment is possible. That is, the amount of displacement in the X direction of the laser beam 2 can be calculated from the detection signals of the optical sensors 6a and 6b. As a result, the laser beam 2 can be centered by adjusting the X direction of the actuator 10. Further, the amount of displacement in the Y direction of the laser beam 2 can be calculated from the detection signals of the optical sensors 6c and 6d. As a result, the laser beam 2 can be centered by adjusting the Y direction of the actuator 10.

Embodiment 5 FIG.
FIG. 8 is a block diagram showing Embodiment 5 of the present invention. In the present embodiment, one optical sensor 6 is disposed so as to be movable around the optical axis of the laser beam 2 on a circumference having a predetermined radius in an XY plane perpendicular to the optical axis of the laser beam 2. Is done. That is, the optical sensor 6 moves to the position of polar coordinates (r, θ), where the optical axis of the laser beam 2 is the origin (0, 0) of the XY coordinates and the radius of the circumference is r.

  By such movement of the optical sensor 6, it becomes possible to detect the spatial distribution of the light emitted from the irradiated portion of the workpiece W as in the first to fourth embodiments, and the nozzle center is determined from the deviation of the light intensity distribution. The amount of displacement and the direction of displacement of the laser beam 2 as a reference can be calculated.

1 laser oscillator, 2 laser light, 3 reflecting mirror, 4 processing lens,
5 processing head, 6, 6a-6d optical sensor, 7 amplifier, 8 numerical control device,
9 signal processing device, 10 actuator, 11 processing nozzle, W workpiece.

Claims (7)

A laser oscillator for generating laser light;
A condensing optical system for condensing the laser beam on the workpiece;
A focused laser beam passes, and a nozzle for supplying gas toward the workpiece;
A processing head for supporting the condensing optical system and the nozzle;
A light detection unit for detecting a spatial distribution of light emitted from the irradiated portion of the workpiece when irradiated with laser light; and
A laser processing apparatus comprising: a signal processing unit for measuring a position of laser light with respect to a nozzle center based on a signal from a light detection unit.   The laser processing apparatus according to claim 1, wherein the light detection unit includes a plurality of optical sensors arranged at equal intervals around the optical axis of the laser light. An actuator for adjusting the position of the condensing optical system with respect to the processing head;
The laser processing apparatus according to claim 1, wherein the signal processing unit controls the actuator so that the laser light passes through the center of the nozzle based on the measurement result. An actuator for adjusting the position of the nozzle with respect to the processing head;
The laser processing apparatus according to claim 1, wherein the signal processing unit controls the actuator so that the laser light passes through the center of the nozzle based on the measurement result. A reflection mirror for introducing laser light from a laser oscillator into a condensing optical system;
An actuator for adjusting the direction of the reflecting mirror;
The laser processing apparatus according to claim 1, wherein the signal processing unit controls the actuator so that the laser light passes through the center of the nozzle based on the measurement result. The actuator has two drive shafts that can be adjusted in a first direction and a second direction orthogonal to each other in a plane perpendicular to the optical axis of the laser beam,
The light detection unit includes four optical sensors arranged at positions where a circumference having a predetermined radius around the optical axis of the laser beam intersects the first direction and a position intersecting the second direction, respectively. The laser processing apparatus according to any one of claims 1 to 5.   The laser processing apparatus according to claim 1, wherein the light detection unit includes an optical sensor movable around the optical axis of the laser light.

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