JPH09216086A - 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 bundled 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 transmitted by the composite type optical fiber 10 is emitted toward a work 1, and an observation part 20 to observe the visible light by branching the visible light generated from the work 1 at the incident part.

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 the laser light energy to the work piece has further expanded the applicable range of the laser processing, and the laser in a pipe having a relatively small diameter is 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. Integrated optical fiber, an incident part for making the processing laser light incident on the composite optical fiber, and emitting the processing laser light transmitted by the composite optical fiber toward the workpiece. It is characterized in that it is provided with an emitting part for observing and a observing part for branching visible light emitted from the workpiece at the incident part and observing this visible light. 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 light guide is transmitted by the composite optical fiber described above and irradiated onto a work piece, and while finely adjusting the distance between the emitting part and the work piece while observing the reflected light from the work piece, After performing a focusing operation, a laser beam for processing is transmitted through the composite optical fiber, and the workpiece is irradiated with this laser beam to process the workpiece.

[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.
The emission lens unit (emission unit) 5 and the observation unit 20 are roughly configured. In the present embodiment, the laser light oscillation device is a high-energy laser light (processing laser light) that can perform processing such as cutting and welding on the workpiece 1.
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. Further, the large number of image transmission fibers 14 are integrated, and form a sea-island structure including a large number of island-shaped cores 15 and sea-shaped clads continuously formed around them. 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. If the number of image transmission fibers 14 (the number of pixels) to be focused is small, the resolution is poor, and if the number is large, the composite optical fiber 10 has a large diameter.
It is preferable that the number is about this.

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 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 can be preferably formed following the spinning of the preform. The thickness and length of the composite optical fiber 10 having such a configuration can be set as appropriate according to the application and the like. For example, the outer diameter is 1.6 to 1.8.
It can be preferably formed to have a length of mm and a length of 6 to 20 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 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 arranged 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 after passing through the incident lens unit 3 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.

In the laser processing apparatus configured as described above, after the processing laser light oscillated from the YAG laser light oscillating device passes through the wavelength filter 21, the incident lens portion 3 causes the composite optical fiber 10 to pass through. The light is condensed and incident on the end surface of the one end side 10a. 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 face of the other end 10b of the composite optical fiber 10 by the emission lens unit 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.

Next, an embodiment 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, if necessary, before laser processing, the distance between the workpiece 1 and the exit lens unit 5 is finely adjusted so that the image near the processing position captured by the imaging device 24 becomes clear. Perform focusing operation. That is, a weak laser beam that oscillates in the visible light wavelength range from an appropriate light source to such an extent that the workpiece 1 is not processed even when the workpiece 1 is irradiated is oscillated, and this is used as a visible guide light to enter the wavelength filter 21 and the incident light. It is incident on the composite optical fiber 10 via the 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. Since an image near the processing position is obtained by the reflected light from the workpiece 1, while observing the image on the television monitor 25, at least the laser processing apparatus itself, at least the emission lens unit 5 and the composite optical fiber unit 10 are at hand. The distance between the exit lens unit 5 and the workpiece 1 is determined so that an image in a focused state can be obtained by moving it forward or backward.

After focusing in this way, the processing position is confirmed, the irradiation of the visible guide light is stopped, and the processing laser beam is oscillated instead of this, and the composite optical fiber 10 is tuned 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.
Since the image transmission fiber 14 for transmitting the image information of the processing position is integrated into a small diameter fiber, even if the processing position is invisible in the pipe, the inner diameter of the pipe or the like 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, in the laser processing apparatus of the present embodiment, the cores of the large-diameter fiber 13 and the image transmission fiber 14 forming the composite optical fiber 10 are
Since both are formed of pure silica, they have excellent radiation resistance and can be suitably used for laser processing in a radiation atmosphere.

According to the laser processing method of this embodiment, the visible guide light is made incident on the composite optical fiber 10 prior to the processing by the laser light, so that the image of the processing position is formed by the reflected light from the workpiece. The image can be focused by finely adjusting the distance between the exit lens unit 5 and the workpiece 1 while observing the image, so that an image in a focused state can be obtained easily and reliably. be able to. In addition, it is not necessary to newly provide a member for focusing operation in the laser processing device simply by preparing a light source of visible guide light.
It is advantageous in terms of size reduction, weight reduction of the device, reduction of the number of parts, cost reduction, and simplification of the assembly process.

[0021]

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 converged 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 It is characterized in that a visible light emitted from the workpiece is branched at the incident part and an observation part for observing the visible light is provided. 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, 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, and thus can be suitably used for laser processing in a radiation atmosphere.

According to the laser processing method of the present invention, a visible light guide is transmitted by the composite optical fiber according to claim 1, and the work is irradiated with the guide light, and the light emitting part is observed while observing the reflected light from the work. After performing a focusing operation by finely adjusting the distance between the workpiece and the workpiece, laser beam for processing is transmitted by the composite optical fiber, and the workpiece is irradiated with this laser beam to process the workpiece. It is characterized by. Therefore, it is possible to easily and surely obtain an image in a focused state. Also, by only preparing a light source of visible guide light, it is not necessary to newly provide a member for focusing operation in the laser processing apparatus, so that the apparatus can be downsized, lightened, the number of parts can be reduced, and the cost can be reduced.
This is advantageous in terms of simplification of the assembly process.

[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.

[Explanation of symbols]

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

 ─────────────────────────────────────────────────── ─── 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 processing apparatus comprising an observation section for observing. 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, which transmits visible guide light to irradiate the workpiece with the guide light, and observes the reflected light from the workpiece while observing the emitting portion and the workpiece. After finely adjusting the distance to perform a focusing operation, a laser beam for processing is transmitted through the composite optical fiber, and the workpiece is irradiated with the laser light for processing to process the workpiece. A laser processing method using the laser processing device according to Item 1.