WO2012014879A1

WO2012014879A1 - Laser processing machine and protective device against laser light

Info

Publication number: WO2012014879A1
Application number: PCT/JP2011/066942
Authority: WO
Inventors: 裕司木野; 茂横井
Original assignee: 三菱電機株式会社
Priority date: 2010-07-28
Filing date: 2011-07-26
Publication date: 2012-02-02
Also published as: JP2013212510A

Abstract

A laser processing machine which causes laser light (La) emitted from a laser oscillator (21) to propagate along a light path and applies the laser light to a workpiece (W) is provided with a bellows (2) which protects the environment of the light path by surrounding the periphery of the light path along the optical axis of the laser light, an aperture (1) which is disposed on the lower stage side of the light path than the bellows (2), passes the laser light (La) therethrough, and blocks reflected light of the laser light (La) reflected by the workpiece (W), a temperature switch (3) which detects the reflected light applied to the aperture (1), and a control unit (50) which controls the operation of the laser oscillator (21) on the basis of the detection result of the reflected light detected by the temperature switch (3), the aperture (1) being formed by a plate-shaped member and disposed so that the principal surface of the plate-shaped member faces the direction perpendicular to the optical axis of the laser light (La).

Description

Laser processing machine and laser beam protection device

The present invention relates to a laser processing machine and a laser beam protection device for protecting an optical path component from reflected light of a laser beam.

In a laser processing machine that performs laser processing on a workpiece by irradiating the workpiece with laser light, the laser beam emitted from the laser oscillator is guided onto the workpiece along a predetermined optical path. In such a laser processing machine, when the reflected light from the workpiece is reflected to the optical path side, a member (optical path component) in the vicinity of the optical path is damaged. For this reason, it is desired to prevent the reflected light from the workpiece from entering the optical path.

For example, in the laser processing machines described in

Patent Documents

1 and 2, an aperture that blocks reflected light (laser light) from the workpiece is provided in the optical path. Thereby, the reflected light largely deviated from the optical path out of the reflected light from the workpiece is prevented from entering the optical path.

JP 2002-316291 A JP 2003-71584 A

However, the conventional technique has a problem in that reflected light that has passed through the aperture enters the optical path, and the reflected light may damage optical path components (such as bellows covering the periphery of the optical path).

The present invention has been made in view of the above, and an object of the present invention is to obtain a laser processing machine and a laser light protection device that protect optical path components from reflected light of laser light.

In order to solve the above-described problems and achieve the object, the present invention provides a laser beam machine for irradiating a workpiece by propagating a laser beam emitted from a laser oscillator along an optical path. An optical path protector that protects the environment of the optical path by surrounding the periphery of the optical path along an axis, and is disposed in the optical path protector or at a lower stage of the optical path than the optical path protector and passes the laser light An aperture that blocks the reflected light of the laser beam reflected by the workpiece, a reflected light detection unit that detects the reflected light applied to the aperture, and a reflected light detected by the reflected light detection unit. A control unit that controls the operation of the laser oscillator based on a detection result, the aperture is formed of a plate-like member, and the main surface of the plate-like member is on the optical axis of the laser beam. Characterized in that it is arranged to face a direction perpendicular to.

According to the present invention, the optical path component can be protected from the reflected light of the laser beam.

FIG. 1 is a diagram showing a configuration of a laser beam machine according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the machining head. FIG. 3 is a diagram showing the arrangement positions of the apertures provided on the optical path of the laser processing machine. FIG. 4 is a diagram for explaining the function of the aperture. FIG. 5 is a diagram showing the configuration of the aperture. FIG. 6 is a diagram for explaining the position of the temperature switch. FIG. 7 is a diagram for explaining reflected light detected by the temperature switch.

Hereinafter, a laser beam machine and a laser beam protection device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a diagram showing a configuration of a laser beam machine according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the machining head. In FIG. 1, the structural example of the laser processing machine 100 is shown as a perspective view, and in FIG. 2, the structural example of the processing head 40 is shown as a perspective view. The laser beam machine 100 includes a laser beam protection device (see FIG. 1) for preventing burning of optical path components due to reflected light (a reflected light Lb described later) from a workpiece (workpiece) W on the optical path of the laser beam. (Not shown). The laser light protection device has an aperture that blocks the reflected light Lb on the optical path, and a temperature detecting means (a temperature switch 3 described later) provided on the aperture detects the surface temperature of the aperture, thereby the aperture. The reflected light Lb applied to the light is detected. Then, the laser light protection device stops the emission of the laser light based on the detection result of the reflected light Lb.

The laser processing machine 100 includes a Y-axis unit movably provided in a Y-axis direction on a work table 32 provided on a bed 31 and a cross rail 36 horizontally stretched between left and right columns 34 and 35. 38. The laser beam machine 100 includes an X-axis unit 37 provided on the cross rail 36 so as to be movable in the X-axis direction, and a Z-axis unit 39 provided on the X-axis unit 37 so as to be movable in the Z-axis direction. Have. Further, the laser processing machine 100 includes a processing head 40 attached to the Z-axis unit 39, a processing nozzle (laser nozzle) 33 attached to the tip of the processing head 40, and a computer-type processing control device 41. is doing.

The machining control device 41 includes an operation panel 42A and a screen display unit 42B such as a CRT as a man-machine interface. The work table 32, the Y-axis unit 38, and the Z-axis unit 39 are driven by an X-axis servo motor, a Y-axis servo motor, and a Z-axis servo motor (not shown), respectively, and position control is performed according to each axis command from the machining control device 41. Is done.

The laser processing machine 100 includes a laser oscillator (laser light output unit) 21 described later, and guides the laser light from the laser oscillator 21 onto the work W along a predetermined optical path. The laser beam machine 100 according to the present embodiment includes an aperture (aperture 1 described later) that prevents the reflected light Lb from entering the optical path through which the laser beam is guided.

FIG. 3 is a diagram showing the arrangement positions of the apertures provided on the optical path of the laser processing machine. The laser processing machine 100 includes a laser oscillator 21, a PR (Partial Reflection) mirror 22, a bend mirror 23, a beam optimization unit 24, bend mirrors 25 and 26, a processing lens 27 provided in the processing head 39, and a laser light protection device. It is comprised including. The laser light protection device includes an aperture 1, a bellows (optical path protection unit) 2, a temperature switch (reflected light detection unit) 3, and a control unit 50.

The laser oscillator 21 is a device that oscillates laser light (beam light) La, such as a CO2 laser, and emits laser light La while changing laser output in various ways during laser processing. The PR mirror (partial reflection mirror) 22 partially reflects the laser beam La emitted from the laser oscillator 21 and guides it to the bend mirror 23. The bend mirror (beam angle changing mirror) 23 changes the beam angle of the laser light La sent from the PR mirror 22 and guides it to the beam optimization unit 24.

The beam optimization unit (beam diameter changing device) 24 adjusts the beam diameter (diameter) of the laser beam La sent from the bend mirror 23 and sends it to the bend mirror 25. The bend mirrors 25 and 26 are mirrors for changing the beam angle. The bend mirror 25 deflects the beam angle of the laser beam La sent from the beam optimization unit 24 in the horizontal direction and sends it to the bend mirror 26. The bend mirror 26 deflects the beam angle of the laser beam La sent from the bend mirror 25 vertically downward and sends it to the processing lens 27. A mirror (not shown) that changes polarization is mounted between the bend mirror 25 and the bend mirror 26.

The processing lens 27 focuses the laser beam from the bend mirror 26 on a small spot diameter and irradiates the workpiece W with it. The work W is placed on the work table 32, and laser processing is performed on the work table 32.

In the laser processing machine 100, a cylindrical bellows 2 formed so as to surround the periphery of the optical path along the optical axis of the laser light La is disposed in the optical path between the bend mirror 25 and the bend mirror 26. . The bellows 2 has a function of protecting the optical path from outside air (processing waste etc.) by blocking the optical path environment from outside air. The bellows 2 is configured to be able to expand and contract in the same direction as the optical path (optical axis), and its shape is changed according to the position and direction of the optical path. In the laser processing machine 100 according to the present embodiment, an aperture 1 that prevents the reflected light Lb from entering is disposed in the vicinity of the bellows 2.

The aperture 1 allows the laser light La to pass therethrough, and out of the reflected light Lb, the reflected light Lb that deviates more than a predetermined amount from the optical path (a predetermined angle from the optical axis of the laser light La) enters the bellows 2. To prevent. The aperture 1 has, for example, a substantially flat plate shape (for example, a plate member having a thickness of 1 mm to 10 mm), and has a through hole (a laser light passage portion 4 to be described later) through which the laser light La passes at the center of the main surface. ) Is provided. The aperture 1 is arranged so that the main surface of the plate-shaped member faces a direction perpendicular to the optical axis of the laser light La. Further, the aperture 1 is provided with a temperature switch 3 as temperature detecting means, and the aperture 1 is provided with an absorber that absorbs the reflected light Lb on the incident surface side of the reflected light Lb (the outgoing slope side of the laser light La). Has been.

The temperature switch 3 detects the temperature of the aperture 1 and sends the detected temperature (measurement result) to the control unit 50. The control unit 50 is a device included in the processing control device 41 and controls the operation of the laser oscillator 21. The control unit 50 according to the present embodiment controls the output of the laser light La from the laser oscillator 21 based on the measurement result (temperature of the aperture 1) sent from the temperature switch 3. Specifically, the control unit 50 stops the output of the laser light La from the laser oscillator 21 when the temperature of the aperture 1 or the rate of temperature increase is higher than a predetermined value.

Here, the function of the aperture 1 will be described. FIG. 4 is a diagram for explaining the function of the aperture. During laser processing, there may be a shift in the focal position of the laser beam La irradiated on the workpiece W, a shift in the optical path of the laser beam La, or the like. In addition, during laser processing, the reflected light Lb from the surface of the workpiece W may be shifted from the optical axis from the laser oscillator 21 and return to the optical path due to the surface state of the workpiece W or the like.

Therefore, in the present embodiment, the aperture 1 is provided in the optical path. This aperture 1 is formed of a member having high thermal conductivity. The aperture 1 is formed using, for example, aluminum, silver, copper, gold, or an alloy using these. In other words, the aperture 1 is formed using at least one of aluminum, silver, copper, and gold, for example. In the case where the aperture 1 is aluminum, the aperture 1 is formed by performing shot blasting on the surface of the aperture 1 of the aluminum base (the emission side of the laser light La) and further subjecting the surface to alumite treatment. The aperture 1 may be configured by combining a plurality of types of metal plates.

Next, the temperature switch 3 provided in the aperture 1 will be described. FIG. 5 is a diagram showing the configuration of the aperture. FIG. 5 shows a perspective view of the aperture 1. The aperture 1 is joined to the bellows 2 on the back surface (bottom surface) side. Thereby, the aperture 1 is arranged so that the back surface side thereof faces the bellows 2 side and the front surface side faces the emission side of the laser light La.

The substantially flat aperture 1 is provided with a laser beam passage portion 4 (for example, a diameter of 50 mm) as a through hole from the front surface side to the back surface side. The laser beam passage portion 4 is provided at the center of the aperture 1 and has a substantially cylindrical shape (cylindrical wall surface).

On the back side of the aperture 1, three temperature switches 3 a to 3 c are arranged as the temperature switch 3. Part or all of the return light (reflected light Lb) reflected from the workpiece W is irradiated on the surface of the aperture 1. The reflected light Lb is absorbed by the aperture 1 and raises the temperature of the aperture 1. The temperature switches 3a to 3c detect the reflected light Lb irradiated to the aperture 1 out of the reflected light Lb by detecting the temperature of the aperture 1. In the present embodiment, a plurality of temperature switches 3 are arranged on the aperture 1. This is to compensate for the difference in detection of heat conduction depending on the absorption position of the reflected light Lb.

The temperature switches 3a to 3c send the detected temperature (measurement result) to the control unit 50. For example, when the temperature measured by the temperature switches 3a to 3c exceeds a predetermined value, the control unit 50 reduces or stops the output of the laser light La, thereby preventing the optical path from being damaged by the reflected light Lb. To do. Note that when the beam output of the laser beam La is lowered, the control unit 50 may control the laser oscillator 21 so as to lower the beam output of the laser beam La by an amount corresponding to the measurement results by the temperature switches 3a to 3c.

Next, the arrangement positions of the temperature switches 3a to 3c will be described. FIG. 6 is a diagram for explaining the position of the temperature switch. FIG. 6 shows a bottom view of the aperture 1. On the bottom surface of the aperture 1, temperature switches 3 a to 3 c are arranged around the laser beam passage portion 4. Each of the temperature switches 3a to 3c is disposed at a position that is equidistant from the center of the laser beam passage portion 4 (the optical axis of the laser beam La), and the distance between adjacent temperature switches is equally spaced. . Here, since there are three temperature switches 3a to 3c, the temperature switches 3a to 3c are arranged on the back surface of the aperture 1 so as to form an equilateral triangle.

The temperature switches 3a to 3c may be disposed in the vicinity of the laser beam passage portion 4, or may be disposed at positions separated from the laser beam passage portion 4 by a predetermined distance as shown in FIG. . For example, by arranging the temperature switches 3a to 3c in the vicinity of the laser beam passage portion 4, a part of the reflected light Lb enters the bellows 2 from the laser beam passage portion 4, and a part of the reflected light Lb It is possible to accurately detect the reflected light Lb when the surface of the aperture 1 is irradiated. Further, when the temperature switches 3a to 3c are arranged at a position away from the laser beam passage portion 4 by a predetermined distance, the reflected light Lb that is significantly larger than the predetermined amount from the optical path among the reflected light Lb is accurately detected. It becomes possible.

Next, the reflected light Lb detected by the temperature switches 3a to 3c will be described. FIG. 7 is a diagram for explaining reflected light detected by the temperature switch. Of the reflected light Lb, the reflected light Lb1 that deviates by a predetermined amount or less from the optical path enters the bellows 2 from the laser light passage portion 4. On the other hand, of the reflected light Lb, the reflected light Lb2 that deviates more than a predetermined amount from the optical path irradiates the surface of the aperture 1, thereby increasing the temperature of the aperture 1. The temperature switches 3a to 3c detect the reflected light Lb2 that irradiates the surface of the aperture 1 among the reflected light Lb.

Thus, in this embodiment, since the surface of the aperture 1 is a beam absorber and the aperture 1 is a member having high thermal conductivity, the detection sensitivity of the reflected light Lb can be improved. Moreover, since the aperture 1 is substantially flat, the detection sensitivity of the reflected light Lb can be improved. In addition, since the surface of the aperture 1 is shot blasted or anodized, the reflected light Lb is less likely to be reflected on the surface of the aperture 1. As a result, it becomes possible to improve the detection sensitivity of the reflected light Lb.

Therefore, the reflected light Lb reflected and diffused by the workpiece W can be detected with high accuracy. Accordingly, it is possible to accurately determine an abnormal state in which reflection on the workpiece W continues, and to stop the laser beam machine 100 before the optical path components such as the bellows 2 are burned out. In other words, the laser beam machine 100 can be stopped by detecting an abnormality that leads to burnout of the optical path component.

In the present embodiment, the case where the aperture 1 is arranged on the laser beam La emission side of the bellows 2 has been described. However, the aperture 1 may be arranged at any position on the optical path. For example, the aperture 1 may be disposed in the bellows 2 or between the bellows 2 and the bend mirror 25. In addition, the aperture 1 may be disposed between the beam optimization unit 24 and the bend mirror 25, or the aperture 1 may be disposed on the optical path upper stage side (laser oscillator 21 side) than the beam optimization unit 24. . Further, the aperture 1 may be disposed on any optical path between the workpiece W and the bellows 2.

Further, although the case where one aperture 1 is disposed in the laser processing machine 100 has been described, two or more apertures 1 may be disposed in the laser processing machine 100. For example, the apertures 1 may be arranged at two locations, the laser beam La emission side of the bellows 2 and the bellows 2. By arranging one aperture 1 and the other aperture 1 at a predetermined interval, the reflected light Lb deviating more than a predetermined angle from the optical axis of the laser light La can be efficiently blocked by the two apertures 1. . In addition, since the aperture 1 is composed of a plate-like member, the temperature of the aperture 1 can be accurately detected.

In addition, a member having extremely high thermal conductivity such as silver or copper is disposed only in a part of the aperture 1 (a region where the detection sensitivity of the laser beam La is to be increased), and aluminum is disposed in the other region. Also good. For example, the aperture 1 may be formed using aluminum, and silver, copper, or the like may be disposed only around the laser beam passage portion 4. Thereby, it is possible to improve the high sensitivity of the laser around the laser beam passage portion 4.

Further, the surface of the aperture 1 may be formed using aluminum, and the back surface of the aperture 1 may be formed using silver or copper. Thereby, shot blasting and anodizing can be performed on the surface of the aperture 1. Therefore, the surface of the aperture 1 can be configured with a member having a high heat absorption rate, and the back surface of the aperture 1 can be configured with a member having an extremely high thermal conductivity.

Further, the reflected light Lb may be detected using a non-contact type temperature sensor instead of the temperature switch 3. In this case, a non-contact type temperature sensor may be arranged on the surface side of the aperture 1. Further, not only the temperature of the aperture 1 when the reflected light Lb irradiates the aperture 1, but also the amount of thermal expansion of the aperture 1, luminance, etc. may be detected. Moreover, although the case where the temperature switch 3 is three was demonstrated in this Embodiment, the temperature switch 3 may be two or less, and may be four or more.

Thus, according to the embodiment, since the aperture 1 is plate-shaped, the amount of heat transfer in the aperture 1 can be increased. As a result, the reflected light Lb that irradiates the surface of the aperture 1 can be accurately detected. Therefore, damage to the optical path component due to the reflected light Lb from the workpiece W can be prevented, and the optical path component can be protected.

Further, since the temperature switches 3a to 3c are arranged on the back surface of the aperture 1 so as to form an equilateral triangle, the reflected light Lb can be accurately detected on the aperture 1. In addition, since the surface of the aperture 1 is shot blasted and anodized, the aperture 1 can efficiently absorb the reflected light Lb. Therefore, the reflected light Lb can be accurately detected on the aperture 1.

As described above, the laser beam machine and the laser beam protection device according to the present invention are suitable for protecting the optical path components from the reflected light of the laser beam.

DESCRIPTION OF SYMBOLS 1 Aperture 2

Bellows

3, 3a-3c Temperature switch 4 Laser light passage part 21 Laser oscillator 41 Processing control apparatus 50 Control part 100 Laser processing machine La Laser light Lb, Lb1, Lb2 Reflected light W Workpiece

Claims

In a laser processing machine that propagates a laser beam emitted from a laser oscillator along an optical path and irradiates a workpiece,
An optical path protection unit for protecting the environment of the optical path by surrounding the periphery of the optical path along the optical axis of the laser beam;
An aperture that is disposed in the optical path protection unit or on the lower side of the optical path than the optical path protection unit, and that allows the laser light to pass therethrough and blocks the reflected light of the laser light reflected by the workpiece;
A reflected light detection unit for detecting reflected light applied to the aperture;
A control unit for controlling the operation of the laser oscillator based on the detection result of the reflected light detected by the reflected light detection unit;
With
2. The laser processing machine according to claim 1, wherein the aperture is formed of a plate-like member, and the main surface of the plate-like member is disposed so as to face a direction perpendicular to the optical axis of the laser beam.
The laser processing machine according to claim 1, wherein the aperture is formed using at least one of aluminum, silver, copper, and gold.
2. The aperture according to claim 1, wherein the aperture is formed using aluminum, and the main surface on the side irradiated with the reflected light of the laser beam is subjected to shot blasting and anodizing. Laser processing machine.
The reflected light detection unit comprises a plurality of,
The reflected light detection position where each of the reflected light detection units detects the reflected light is a position on the aperture and a position away from the optical axis of the laser light by the same distance. Item 4. The laser beam machine according to any one of Items 1 to 3.
The reflected light detection unit is arranged on a main surface of the main surface of the aperture opposite to the main surface on the side irradiated with the reflected light of the laser light. 4. The laser beam machine according to any one of 4 above.
The laser beam machine according to any one of claims 1 to 5, wherein the reflected light detection unit detects reflected light applied to the aperture by detecting a surface temperature of the aperture. .
In a laser light protection device that protects optical path components arranged on the optical path from laser light emitted from a laser oscillator and propagated along the optical path,
An optical path protection unit for protecting the environment of the optical path by surrounding the periphery of the optical path along the optical axis of the laser beam;
An aperture that is disposed in the optical path protection unit or on the lower side of the optical path than the optical path protection unit, and that allows the laser light to pass therethrough and blocks the reflected light of the laser light reflected by the workpiece;
A reflected light detection unit for detecting reflected light applied to the aperture;
A control unit for controlling the operation of the laser oscillator based on the detection result of the reflected light detected by the reflected light detection unit;
With
The aperture is formed by a plate-like member, and the main surface of the plate-like member is arranged so as to face a direction perpendicular to the optical axis of the laser beam.