JPH09216087A - Laser beam machine and laser beam machining method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe the machining position simultaneously with the laser beam machining even when a machining position is in an invisible part such as in the piping. SOLUTION: A laser beam machine is provided with a composite type optical fiber 10 in which a large number of fibers 14 for image transmission are assembled and integrated around a large diameter fiber 13 for machining laser beam transmission, an incident part in which the machining laser beam is incident on the composite type optical fiber 10, an emission part 5 in which the machining laser beam to be transmitted by the composite type optical fiber 10 is emitted toward a work 1, an observation part 20 to observe the visible light by branching the visible light generated from the work 1 at the incident part, and a focal point adjusting part 30 to operate the focusing through fine adjustment of the distance of the emission part 5 and the work 1 based on the image information obtained by the observation part 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus using an optical fiber, and a laser capable of performing laser processing while observing a processing state even in a portion such as a pipe which is not directly visible. The present invention relates to a processing device and a laser processing method.

[0002]

2. Description of the Related Art Conventionally, laser light has been used as a non-contact tool for processing various materials. Then, the development of a laser processing device using an optical fiber as an optical system for transmitting laser light energy to a work piece has expanded the applicable range of the laser processing further, and the laser in a pipe with a relatively small diameter has been developed. Processing is also possible. For example, when performing welding or cutting with a laser processing device that uses an optical fiber, the processing laser light oscillated from the laser is guided by the optical fiber, and a laser beam is focused on the workpiece using a focusing optical system. Various laser processing can be performed by converging light.

[0003]

By the way, the grasping of the machining position, the confirmation of the machining state after machining, the inspection, etc. are usually performed visually. However, when it is not possible to visually check the processing position, such as when the processing position is inside the pipe, a device for observing the processing position such as a fiberscope is necessary in addition to the laser processing device. Then, by inserting the laser processing device and the fiberscope into the pipe at the same time, it is possible to accurately grasp the processing position, that is, the position to which the laser beam is irradiated, or perform the processing while observing the processing state. If the inner diameter is small,
There is a disadvantage that the laser processing device and the fiberscope cannot be inserted at the same time.

If the laser processing device and the fiberscope cannot be inserted into the pipe at the same time, it is impossible to perform the processing while observing the processing state, and it is difficult to accurately grasp the processing position. Furthermore, in the post-processing inspection, it is difficult to confirm the processing position because it is necessary to take out the laser processing device from the inside of the pipe after the completion of processing and then insert the fiberscope in its place. There was an inconvenience that it became very bad.

The present invention has been made in view of the above circumstances, and provides a laser processing apparatus and a laser processing method capable of observing the processing position at the same time as the laser processing even when the processing position is invisible in a pipe or the like. For the purpose of provision.

[0006]

In order to solve the above-mentioned problems, the laser processing apparatus according to claim 1 of the present invention is such that a large number of image transmitting fibers are focused around a large-diameter fiber for transmitting a processing laser beam. And integrated composite optical fiber, an incident part for entering the processing laser light into the composite optical fiber, and emitting the processing laser light transmitted by the composite optical fiber toward the workpiece. Based on the image information obtained by the emission part, the visible light emitted from the work piece is branched at the incident part, and the visible light is observed, and the observation part, the emission part and the work piece are It is characterized in that it is provided with a focus adjusting section for performing a focusing operation by finely adjusting the distance. Preferably, the cores of the large diameter fiber and the image transmission fiber are made of pure silica.

Further, the laser processing method of the present invention is described in claim 1.
A visible guide light having a mask pattern is incident on the composite optical fiber described above, and a focusing operation is performed by the focus adjusting unit in a state in which the workpiece is irradiated with the visible guide light, and then a processing laser is applied to the composite optical fiber. It is characterized in that light is made incident and the light is irradiated to the work to process the work.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
FIG. 1 is a schematic configuration diagram showing an embodiment of the laser processing apparatus of the present invention. Reference numeral 1 in the drawing is a workpiece. The laser processing apparatus according to the present embodiment includes a composite optical fiber 10, a laser light oscillation device (not shown), and an incident section including an incident lens section 3.
Emitting lens unit (emission unit) 5, observing unit 20, focus adjusting unit 3
0 and the guide light incident part 40. In the present embodiment, the laser light oscillation device is the workpiece 1
A high-energy laser beam (processing laser beam) that can be used for processing such as cutting and welding is output, and a YAG laser is preferably used.

FIG. 2 is a sectional view showing an example of the composite optical fiber 10. Reference numeral 13 in the figure is a large-diameter fiber.
The large-diameter fiber in the present invention means an optical fiber having a core diameter capable of transmitting optical power without being substantially affected by the cladding. Large-diameter fiber 1 of this embodiment
3 is a core 11 made of pure silica, fluorine and /
Alternatively, the cladding 12 is made of silica to which boron is added. The diameter of the core 11 is 600 to 800 μm,
The clad 12 is preferably formed to have a diameter of about 800 to 1000 μm and a numerical aperture (NA) of about 0.2.

A large number of image transmission fibers 14 are bundled around the large diameter fiber 13. The large number of image transmission fibers 14 are integrated to form a sea-island structure including a large number of island-shaped cores 15 and sea-shaped clads formed continuously around the cores 15. The core 15 is made of pure silica, the clad is made of silica to which fluorine and / or boron is added, and the diameter (pixel diameter) of the core 15 is preferably formed to be about 9 to 10 μm. Further, if the number of image transmission fibers 14 (the number of pixels) to be focused is small, the resolution is deteriorated, and if the number is large, the composite optical fiber 10 has a large diameter.
It is preferable that the number is about 00.

The composite optical fiber 10 in this embodiment
Is a large diameter fiber 13 at the center of the quartz jacket tube 16.
Is manufactured by forming a preform by arranging a rod of No. 3, an optical fiber serving as the image transmission fiber 14 is packed around the rod, and spinning the preform. The quartz jacket tube 16 is made of pure silica, and its size is appropriately set according to the number of pixels. A resin coating layer 17 is formed on the circumference of the quartz jacket tube 16. The resin coating layer 17 is preferably formed by using UV resin and preferably has a thickness of about 100 to 200 μm. The resin coating layer 17 is formed following the spinning of the preform. The composite optical fiber 10 having such a configuration
The thickness and the length of the can be appropriately set according to the application etc., but for example, the outer diameter is 1.6 to 1.8 mm and the length is 6 to 2.
It can be formed preferably to about 0 m.

The incident lens unit 3 collects and injects a processing laser beam (infrared ray) oscillated from a YAG laser beam oscillator (not shown) onto the end face of the composite optical fiber 10 on one end side 10a. Is configured. Further, the emission lens unit 5 is configured to collect and irradiate the processing laser light emitted from the end face of the other end side 10b of the composite optical fiber 10 onto the workpiece 1. The emitting lens unit 5 also includes a drive mechanism 32 that moves the emitting lens unit 5 forward and backward in the optical axis direction of the processing laser light. Thus, the distance between the exit lens portion 5 and the work piece 1 can be finely adjusted while keeping the distance between the composite optical fiber 10 and the work piece 1 constant.

The observation unit 20 includes a wavelength filter 21, an infrared cut filter 22, an image pickup lens 23, an image pickup device 24,
And a television monitor 25. The wavelength filter 21 is configured to transmit infrared rays, and also partially transmit visible light and partially reflect visible light. The wavelength filter 21 is disposed between the laser light oscillation device and the incident lens unit 3, transmits the processing laser light and a visible guide light described later, and also transmits the processing laser light on the same optical axis as the processing laser light. The visible light transmitted in the opposite direction is reflected and branched to an optical path different from the optical path of the processing laser light. The wavelength filter 21 can be preferably configured by using, for example, a dielectric multilayer filter.

The infrared cut filter 22 is constructed so as to transmit the visible light branched by the wavelength filter 21 and cut the infrared light, and can be suitably constructed by using a dielectric multilayer film filter. Imaging lens 23
Is configured to collect visible light that has passed through the infrared cut filter 22 on the light receiving surface of the image pickup device 24 and form an image. The image pickup device 24 outputs the luminance distribution of the light pattern formed on the light receiving surface as an electric signal (image signal), and a CCD camera is preferably used, for example. The image information imaged by the imaging device 24 in this manner is sent to the television monitor 25 and displayed as an image.

The focus adjustment unit 30 is composed of an image processing device 31 and a drive mechanism 32 provided in the emission lens unit 5. The image processing device 31 receives the image information captured by the image capturing device 24 from the image capturing device 24 or the television monitor 25, measures the brightness distribution of the image, detects the contrast of the brightness distribution, and measures the contrast. It has a means for outputting a signal for driving the drive mechanism 32 so that the maximum value is maximized, and can be configured appropriately.

The guide light incident section 40 is for making visible guide light having a mask pattern incident on the composite optical fiber 10, and includes a guide light source (not shown), a mask 41, and
And a mirror 42. The guide light source used here is a light having a wavelength in the visible region, and may be any light as long as it can oscillate light (visible guide light) that does not change the surface state of the workpiece 1 when it is irradiated. Can be used.

The mask 41 has a portion through which visible guide light is transmitted and a portion through which visible guide light is not transmitted.
It is arranged between the guide light source and the mirror 42. The visible guide light has a mask pattern by passing through the mask 41. For example, when the mask 41 in which the portion through which the visible guide light is transmitted is formed in a cross shape is used, the visible guide light having a cross-shaped mask pattern as shown in FIG. 3 is obtained. The shape of the mask can be set appropriately. The mirror 42 is configured to transmit infrared light and reflect visible light. Mirror 42
Is arranged between the wavelength filter 21 and the laser light oscillator, and is configured to guide light from a guide light source provided separately from the laser light oscillator on the same optical axis as the laser light.

In the laser processing apparatus configured as described above, the processing laser light oscillated from the YAG laser light oscillating device passes through the mirror 42 and the wavelength filter 21 and then is combined by the incident lens unit 3. Type optical fiber 1
The light is focused on the end face on the one end side 10a of 0 and is incident. Then, the light is transmitted by the large-diameter fiber 13 of the composite optical fiber 10, emitted from the other end side 10b of the composite optical fiber 10, and then focused on the workpiece 1 by the emission lens unit 5. In this way, when the workpiece 1 is irradiated with the high-energy processing laser beam, the workpiece 1 melts or evaporates, so that the workpiece 1 can be processed as desired. At the same time, the workpiece 1 is heated to emit visible light.

This visible light is condensed on the end surface of the other end 10b of the composite optical fiber 10 by the exit lens portion 5,
After being transmitted by the image transmission fiber 14 of the composite optical fiber 10, one end side 10 a of the composite optical fiber 10 is transmitted.
Is emitted from. Then, after being made into parallel light by the incident lens unit 3, it is reflected by the wavelength filter 21 and branched to an optical path different from the optical path of the laser light. The branched visible light passes through the infrared cut filter 22, and then is imaged on the light receiving surface of the image pickup device 24 by the image pickup lens 23.
The image formed here is an image in the vicinity of the processing position of the workpiece 1, is picked up by the image pickup device, and is displayed on the television monitor 25.

Focusing operation can be performed by oscillating the visible guide light from the guide light source without oscillating the processing laser light. That is, the guide light source oscillates visible guide light, and the mask 41, the mirror 42,
When entering the composite optical fiber 10 through the wavelength filter 21 and the entrance lens 3, visible guide light having a mask pattern is transmitted by the image transmission fiber 14 of the composite optical fiber 10 and is irradiated to the workpiece 1. It
Then, the reflected light from the workpiece 1 is branched by the wavelength filter 21 in the same manner as the visible light emitted from the workpiece 1 described above, is imaged on the light receiving surface of the image pickup device 24, and is imaged. The image information picked up by the image pickup device 24 is sent to the television monitor 25 and displayed as an image, and is also sent to the image processing device 31.

When the image information is sent, the image processing device 31 measures the brightness distribution of the image and detects the contrast of this brightness distribution. For example, FIG. 4 shows an example of an image obtained on the television monitor 25 and its luminance distribution when the visible guide light having the mask pattern shown in FIG. 4 (a)-
(C) shows images obtained respectively when the exit lens unit 5 is moved, (a) shows a state where the exit lens unit 5 is closer to the workpiece 1 than the focal position, and (b) shows The focus position and the state (c) are farther from the focus position, respectively.

As shown in FIG. 4, the contrast of the luminance distribution is maximum in the in-focus state (b),
The image processing device 31 outputs a signal for driving the drive mechanism 32 of the emitting lens unit 5 based on the result of detecting the contrast of the luminance distribution, and moves the emitting lens 5 so that the contrast of the luminance distribution is maximized. That is, the distance between the exit lens unit 5 and the workpiece 1 is finely adjusted so that the obtained image is in focus. The distance between the exit lens unit 2 and the workpiece 1 is finely adjusted in this manner only when the visible guide light is incident on the composite optical fiber 10 to perform the focusing operation, and in other cases. In addition, for example, by preventing the image information from being sent to the image processing device 31, the distance between the exit lens unit 2 and the workpiece 1 does not change.

Next, an example of a laser processing method using the laser processing apparatus of this embodiment will be described. First, the emitting lens unit 5 of the laser processing apparatus is arranged near the processing position of the workpiece 1, and the laser processing apparatus is set so that the processing laser light is emitted toward the processing position. Then, a visible guide light is oscillated from the guide light source to perform a focusing operation. That is, the visible guide light is passed through the mask 41 and has a mask pattern, which is
2. It is made incident on the composite optical fiber 10 through the wavelength filter 21 and the incident lens unit 3. This visible guide light is transmitted by the image transmission fiber 14 of the composite optical fiber 10 and is applied to the workpiece 1. And the work piece 1
Since an image in the vicinity of the processing position is obtained by the reflected light from, the focus adjustment unit 30 automatically performs the focusing operation based on this image information.

After focusing in this manner, the processing position is confirmed, the oscillation of the visible guide light is stopped, and the laser light for processing is oscillated instead of this, and the composite optical fiber 10 is passed through the wavelength filter 21. Incident on. The processing laser light is transmitted by the large-diameter fiber 13 of the composite optical fiber 10 as described above, and is emitted from the emitting lens portion 5 toward the workpiece 1, so that the workpiece 1 is processed.
Can be processed as desired. At this time, as described above, since the image near the processing position obtained by the visible light emitted from the workpiece 1 is displayed on the television monitor 25, the processing can be performed while observing the image. When the surface state of the workpiece 1 reaches the desired processing state, the oscillation of the laser light is stopped and the processing is finished. After that, when it is necessary to further confirm the processing state, a visible guide light is made incident on the composite optical fiber 10 in the same manner as the above focusing operation to obtain an image of the processing position, and by observing this, The processing status can be confirmed.

As described above, according to the laser processing apparatus of this embodiment, the large diameter fiber 13 for transmitting the processing laser light is used.
And the image transmission fiber 14 for transmitting the image information of the processing position are integrated into a fiber having a small diameter, so that even if the processing position is invisible such as inside the pipe, the inside diameter of the pipe is small. However, if the size of the composite optical fiber 10 and the exit lens unit 5 is insertable, an image of the processing position can be obtained at the same time as the irradiation of the processing laser light. Therefore, laser processing can be performed while observing the processing state from this image.

Further, the laser processing apparatus of this embodiment is provided with a focus adjusting section 30 for performing a focusing operation based on the image information obtained by the observing section 20, so that the focusing operation is automatically performed. The operation is simple and the work efficiency can be improved. In the present embodiment, the exit lens unit 5 has a drive mechanism 32 capable of finely adjusting the distance between the exit lens unit 5 and the workpiece 1 while keeping the distance between the composite optical fiber 10 and the workpiece 1 constant. Is equipped with. Therefore, the focusing operation can be performed without moving the composite optical fiber 10. With this configuration, when the distance from the hand to the work piece 1 is long, or when the composite optical fiber 10 is inserted in a pipe having a bend or the like, the composite optical fiber 10 is moved in the length direction thereof. It is particularly preferable when it is difficult to do so.

Further, since the guide light incidence part 40 for making visible light guide having a mask pattern incident on the composite type optical fiber 10 is provided, the focusing operation and the laser processing operation can be easily switched. Further, since the visible guide light has the mask pattern, the automatic focusing operation by the focus adjusting unit 30 is accurately performed. Further, the laser processing apparatus of this embodiment is excellent in radiation resistance because the cores of the large diameter fiber 13 and the image transmission fiber 14 which compose the composite optical fiber 10 are made of pure silica. Therefore, it can be suitably used for laser processing in a radiation atmosphere.

According to the laser processing method of this embodiment, the guide light having the mask pattern is made incident on the composite optical fiber 10 prior to the processing by the laser light, so that the processing position is reflected by the light reflected from the workpiece. Image of
Based on the change in the contrast ratio of the brightness distribution of the image, the focus adjusting unit 30 causes the exit lens unit 5 and the workpiece 1 to be processed.
Since the distance between and is finely adjusted and the focusing operation is performed, it is possible to automatically and surely obtain an image in a focused state. Therefore, laser processing while observing the processing position can be performed easily and efficiently.
The mechanism of the focus adjustment unit 30 is not limited to that of this embodiment,
The mechanism can be appropriately changed as long as it is a mechanism for automatically performing the focusing operation based on the image information obtained by the observation unit 20. For example,
The exit lens unit 5 is connected to the other end side 10b of the composite optical fiber 10.
The other end side 10 of the composite optical fiber 10 is fixed to the end face of the composite optical fiber 10 and can be moved in the pipe by remote control.
It is also possible to attach the end of b and to make the robot move based on the image information obtained by the observation unit 20. In this case, the entire composite optical fiber 10 is moved back and forth to perform the focusing operation. be able to.

[0029]

As described above, in the laser processing apparatus according to the first aspect of the present invention, a large number of image transmission fibers are bundled and integrated around a large-diameter fiber for processing laser light transmission. A composite optical fiber, an entrance portion for entering the processing laser light into the composite optical fiber, an emission portion for emitting the processing laser light transmitted by the composite optical fiber toward a workpiece, and a workpiece Visible light emitted from an object is branched at the incident part, and based on image information obtained by the observing part and the observing part, the distance between the emitting part and the workpiece is finely adjusted. It is characterized by comprising a focus adjustment section for performing a focusing operation. Therefore, even if the processing position is invisible, such as inside the pipe, you can insert the composite optical fiber and the emission part into the pipe and obtain an image of the processing position at the same time as laser irradiation. Meanwhile, laser processing can be performed.

Further, a focus adjusting section for performing a focusing operation based on the image information obtained by the observing section is provided, so that the focusing operation is automatically performed, so that the operation is simple and the working efficiency is improved. Can be made. Furthermore, since the laser processing apparatus in which the cores of the large diameter fiber and the image transmission fiber are made of pure silica has excellent radiation resistance, it can be suitably used for laser processing in a radiation atmosphere.

According to the laser processing method of the present invention, a visible guide light having a mask pattern is made incident on the composite optical fiber according to claim 1, and a focusing operation is performed by the focus adjusting unit in a state where the visible guide light is irradiated to the workpiece. After performing, the processing laser beam is made incident on the composite optical fiber, and the workpiece is irradiated with this laser beam to process the workpiece. Therefore, it is possible to automatically and surely obtain an image in a focused state. Therefore, laser processing while observing the processing position can be performed easily and efficiently.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a laser processing apparatus of the present invention.

FIG. 2 is a cross-sectional view showing an example of a composite optical fiber that is preferably used in the laser processing apparatus of the present invention.

FIG. 3 is an explanatory view showing an example of visible guide light having a mask pattern according to the present invention.

FIG. 4 is an explanatory diagram showing an example of an image obtained by irradiating the workpiece with the visible guide light of FIG. 3 and its luminance distribution.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Workpiece, 3 ... Incident lens part, 5 ... Emitting lens part (emitter part), 10 ... Composite optical fiber, 13 ... Large diameter fiber, 14 ... Image transmission fiber, 20 ... Observation part, 3
0 ... Focus adjustment section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Oka No. 1 Mukaeyama, Naka-cho, Naka-cho, Naka-gun, Ibaraki Prefecture

Claims (3)

[Claims] 1. A composite optical fiber in which a large number of image transmission fibers are converged and integrated around a large-diameter fiber for processing laser light transmission, and processing laser light is incident on the composite optical fiber. The incident part, the emitting part that emits the processing laser light transmitted by the composite optical fiber toward the workpiece, and the visible light emitted from the workpiece is branched at the incident part. A laser comprising an observing section for observing and a focus adjusting section for performing a focusing operation by finely adjusting the distance between the emitting section and the workpiece based on the image information obtained by the observing section. Processing equipment. 2. The laser processing apparatus according to claim 1, wherein the cores of the large-diameter fiber and the image transmission fiber are made of pure silica. 3. The composite optical fiber according to claim 1, wherein visible guide light having a mask pattern is made incident, and a focus operation is performed by the focus adjusting unit in a state where the visible guide light is irradiated to a workpiece, 2. A laser processing method using a laser processing apparatus according to claim 1, wherein a laser beam for processing is made incident on the composite optical fiber, and the processed object is irradiated with the laser beam for processing to process the object.