JP3746554B2 - Laser processing apparatus and laser processing method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus using an optical fiber, and more particularly to a laser processing apparatus and a laser processing method capable of performing laser processing while observing a processing state even on a part that cannot be directly visually observed, such as in a pipe. .
[0002]
[Prior art]
Conventionally, laser light has been used as a non-contact tool for processing various materials. As a result of the development of laser processing equipment using optical fibers as an optical system for transmitting laser light energy to the workpiece, the applicable range of laser processing has further expanded, and lasers in relatively small diameter pipes can be used. Processing is also possible.
For example, when welding or cutting is performed by a laser processing apparatus using an optical fiber, the processing laser light oscillated from the laser is guided by the optical fiber, and the laser is applied to the workpiece using a condensing optical system. Various laser processing can be performed by condensing the light.
[0003]
[Problems to be solved by the invention]
By the way, grasping of a processing position, confirmation of a processing state after processing, inspection, and the like are usually performed visually.
However, when it is impossible to visually check the processing position, for example, when the processing position is in a pipe, a device for observing the processing position such as a fiber scope is required in addition to the laser processing device. And 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 irradiate the laser beam, or to process while observing the processing state. If the inner diameter is small, the laser processing apparatus and the fiberscope cannot be inserted at the same time.
[0004]
If the laser processing device and the fiberscope cannot be inserted into the pipe or the like at the same time, it is impossible to perform 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 insert the fiberscope instead of the laser processing device after removing the laser processing device from the pipe after the processing is completed. There was an inconvenience that became very bad.
[0005]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a laser processing apparatus and a laser processing method capable of observing a processing position at the same time as laser processing even when the processing position is in an invisible part such as a pipe. And
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a laser processing apparatus according to claim 1 of the present invention is a composite type in which a large number of image transmission fibers are converged and integrated around a large diameter fiber for processing laser light transmission. From an optical fiber, an incident part that makes processing laser light incident on the composite optical fiber, an output part that emits processing laser light transmitted by the composite optical fiber toward the work piece, and a work piece splits the light emitting visible light in the incident portion, Ri Na includes an observation unit for observing the visible light, wherein the image transmission fiber has a large number of island-shaped core, are formed continuously around them had no sea-island structure composed of sea-like cladding is characterized in Rukoto.
Preferably, the cores of the large diameter fiber and the image transmission fiber are made of pure silica.
[0007]
Further, the laser processing method of the present invention transmits visible guide light through the composite optical fiber according to claim 1 and irradiates the workpiece with the visible guide light, and observes the reflected light from the workpiece and After finely adjusting the distance to the workpiece and performing the focusing operation, the machining laser beam is transmitted through the composite optical fiber and irradiated on the workpiece to process the workpiece. It is a feature.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. FIG. 1 is a schematic configuration diagram showing an embodiment of a laser processing apparatus of the present invention. Reference numeral 1 in the figure denotes a workpiece.
The laser processing apparatus of the present embodiment is roughly constituted by a composite optical fiber 10, an incident part provided with a laser light oscillation device (not shown) and an incident lens part 3, an exit lens part (exit part) 5, and an observation part 20. ing.
In this embodiment, the laser beam oscillator outputs a high-energy laser beam (processing laser beam) that can perform processing such as cutting and welding on the workpiece 1, and a YAG laser is preferable. Used.
[0009]
FIG. 2 is a cross-sectional view showing an example of the composite optical fiber 10. Reference numeral 13 in the figure denotes a large diameter fiber.
The large-diameter fiber in the present invention refers to an optical fiber having a core diameter that can transmit optical power with almost no influence of the cladding.
The large-diameter fiber 13 of this embodiment is composed of a core 11 made of pure silica and a clad 12 made of silica to which fluorine and / or boron is added. Preferably, the core 11 has a diameter of 600 to 800 μm, the cladding 12 has a diameter of about 800 to 1000 μm, and a numerical aperture (NA) of about 0.2.
[0010]
A large number of image transmission fibers 14 are focused around the large-diameter fiber 13. The multiple image transmission fibers 14 are integrated to form a sea-island structure including a large number of island-shaped cores 15 and a sea-shaped clad 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 of the core 15 (pixel diameter) is preferably about 9 to 10 μm. Further, if the number of image transmission fibers 14 (number of pixels) to be focused is small, the resolution is poor, and if it is large, the composite optical fiber 10 has a large diameter. Therefore, the number is preferably about 3000 to 10,000.
[0011]
The composite optical fiber 10 in this embodiment has a large-diameter fiber 13 rod disposed at the center of a quartz jacket tube 16, and an optical fiber to be an image transmission fiber 14 is formed around the rod to form a preform. It is manufactured by spinning a preform.
The quartz jacket tube 16 is made of pure silica, and the size thereof 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 using a 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 preferably 1.6 to 1.8 mm and the length is preferably about 6 to 20 m. Can be formed.
[0012]
The incident lens unit 3 is configured so that processing laser light (infrared rays) oscillated from a YAG laser light oscillation device (not shown) is condensed and incident on the end face of one end side 10 a of the composite optical fiber 10. Has been.
Further, the exit lens unit 5 is configured to collect and irradiate the processing laser light emitted from the end surface of the other end side 10 b of the composite optical fiber 10 on the workpiece 1.
[0013]
The observation unit 20 includes a wavelength filter 21, an infrared cut filter 22, an imaging lens 23, an imaging device 24, and a television monitor 25.
The wavelength filter 21 is configured to transmit infrared rays and partially transmit visible light and partially reflect. The wavelength filter 21 is disposed between the laser light oscillation device and the incident lens unit 3 and transmits the processing laser light and the visible guide light described later, and 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 configured using, for example, a dielectric multilayer filter.
[0014]
The infrared cut filter 22 is configured to transmit visible light branched by the wavelength filter 21 and cut infrared light, and can be configured using a dielectric multilayer filter suitably.
The imaging lens 23 is configured to focus the visible light that has passed through the infrared cut filter 22 on the light receiving surface of the imaging device 24 to form an image.
The imaging device 24 outputs the luminance distribution of the light pattern imaged on the light receiving surface as an electrical signal (image signal), and for example, a CCD camera is preferably used. The image information captured by the imaging device 24 in this way is sent to the television monitor 25 and displayed as an image.
[0015]
In the laser processing apparatus configured as described above, after the processing laser light oscillated from the YAG laser light oscillation apparatus passes through the wavelength filter 21, one end side of the composite optical fiber 10 is formed by the incident lens unit 3. The light is condensed and incident on the end face of 10a. Then, the light is transmitted through the large-diameter fiber 13 of the composite optical fiber 10, emitted from the other end side 10 b of the composite optical fiber 10, and then condensed on the workpiece 1 by the exit lens unit 5. In this way, when the workpiece 1 is irradiated with the high-energy machining 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.
[0016]
This visible light is condensed on the end face of the other end side 10 b of the composite optical fiber 10 by the exit lens unit 5, transmitted by the image transmission fiber 14 of the composite optical fiber 10, and then the composite optical fiber 10. The light is emitted from one end side 10a. Then, after being made 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 is then imaged on the light receiving surface of the imaging device 24 by the imaging lens 23. The image formed here is an image in the vicinity of the processing position of the workpiece 1 and is captured by the imaging device and displayed on the television monitor 25.
[0017]
Next, an embodiment of a laser processing method using the laser processing apparatus of this embodiment will be described.
First, the exit lens portion 5 of the laser processing apparatus is arranged in the vicinity of 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.
If necessary, prior to laser processing, the distance between the workpiece 1 and the exit lens unit 5 is finely adjusted so that an image near the processing position picked up by the image pickup device 24 becomes clear. Perform focusing operation. That is, a laser beam that is weak enough to be processed in the wavelength range of visible light from an appropriate light source and is not processed even when the workpiece 1 is irradiated is oscillated, and this is used as the visible guide light to the wavelength filter 21 and the incident light. The light enters the composite optical fiber 10 through the lens unit 3. The visible guide light is transmitted through the image transmission fiber 14 of the composite optical fiber 10 and is irradiated onto the workpiece 1. Then, since an image near the processing position is obtained by the reflected light from the workpiece 1, the laser processing apparatus itself, at least the output lens unit 5 and the composite optical fiber unit 10 are hand-held while observing the image on the television monitor 25. The distance between the exit lens unit 5 and the workpiece 1 is determined so as to obtain an in-focus image by moving forward and backward.
[0018]
After focusing in this manner, the processing position is confirmed, the irradiation of the visible guide light is stopped, and instead, the processing laser light is oscillated and incident on the composite optical fiber 10 via the wavelength filter 21. .
As described above, the processing laser light is transmitted by the large-diameter fiber 13 of the composite optical fiber 10 and is emitted from the exit lens unit 5 toward the workpiece 1, so that the processing laser beam is directed toward the workpiece 1. Desired processing can be performed. At this time, as described above, an image in the vicinity of the processing position obtained by the visible light emitted from the workpiece 1 is displayed on the television monitor 25, so that the processing can be performed while observing the image.
When the surface state of the workpiece 1 reaches a desired processing state, the oscillation of the laser beam is stopped and the processing ends.
After this, if further confirmation of the processing state is required, the visible guide light is 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 state can be confirmed.
[0019]
As described above, according to the laser processing apparatus of the present embodiment, a small-diameter fiber in which the large-diameter fiber 13 that transmits the processing laser light and the image transmission fiber 14 that transmits the image information of the processing position are integrated. Therefore, even if the processing position is not visible, such as in the pipe, the processing laser can be used as long as the inner diameter of the pipe or the like is large enough to insert the composite optical fiber 10 and the exit lens portion 5. An image of the processing position can be obtained simultaneously with the light irradiation. Therefore, laser processing can be performed while observing the processing state from this image.
Further, the laser processing apparatus of this embodiment has excellent radiation resistance because the cores of the large-diameter fiber 13 and the image transmission fiber 14 constituting the composite optical fiber 10 are both made of pure silica. And can be suitably used for laser processing in a radiation atmosphere.
[0020]
According to the laser processing method of this embodiment, prior to processing with laser light, the visible light is incident on the composite optical fiber 10 to obtain an image of the processing position by reflected light from the workpiece. Since the image can be focused by finely adjusting the distance between the exit lens unit 5 and the workpiece 1 while observing the image, an image in a focused state can be obtained easily and reliably. . In addition, only by preparing a light source for visible guide light, there is no need to provide a new focus processing member in the laser processing device, so the size and weight of the device, the number of parts, cost reduction, and assembly process can be reduced. This is advantageous in terms of simplification.
[0021]
【The invention's effect】
As described above, the laser processing apparatus according to claim 1 of the present invention is 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 an incident portion for entering the processing laser light into the composite optical fiber, an emitting portion for emitting the processing laser light transmitted by the composite optical fiber toward the workpiece, and emitting light from the workpiece. Visible light is branched at the incident part, and an observation part for observing the visible light is provided.
Therefore, even if the machining position is not visible, such as in the pipe, the composite optical fiber and the emission part can be inserted into the pipe, etc., and an image of the machining position can be obtained simultaneously with the laser irradiation. Laser processing can be performed.
A laser processing apparatus in which the core of the large-diameter fiber and the image transmission fiber is made of pure silica is excellent in radiation resistance, and can be suitably used for laser processing in a radiation atmosphere.
[0022]
The laser processing method of the present invention transmits the visible guide light by the composite optical fiber according to claim 1 and irradiates the workpiece with the visible guide light, and observes the reflected light from the workpiece and the emitting portion and the workpiece. After finely adjusting the distance to the object and performing a focusing operation, the laser beam for processing is transmitted through the composite optical fiber, and the object is irradiated with the laser beam, thereby processing the object To do.
Therefore, an image in a focused state can be obtained simply and reliably. In addition, only by preparing a light source for visible guide light, there is no need to provide a new focus processing member in the laser processing device, so the size and weight of the device, the number of parts, cost reduction, and assembly process can be reduced. This is advantageous in terms of simplification.
[Brief description of the 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 ... Outgoing lens part (outgoing part),
10 ... composite optical fiber, 13 ... large diameter fiber,
14 ... Fiber for image transmission, 20 ... Observation part.

Claims (3)

A composite optical fiber in which a large number of image transmission fibers are focused and integrated around a large-diameter fiber for processing laser light transmission;
An incident portion for injecting a processing laser beam into the composite optical fiber;
An emission unit for emitting the processing laser beam transmitted by the composite optical fiber toward the workpiece;
The visible light emitting from the workpiece branched at the incident portion, Ri Na includes an observation unit for observing the visible light,
The image transmission fiber comprises a plurality of island-like core, these laser processing apparatus characterized that you have no sea-island structure composed of a continuous sea shape formed by cladding the periphery.   2. The laser processing apparatus according to claim 1, wherein the core of the large-diameter fiber and the image transmission fiber is made of pure silica.   The visible light is transmitted through the composite optical fiber according to claim 1 and irradiated onto the workpiece, and the distance between the emitting portion and the workpiece is finely adjusted while observing the reflected light from the workpiece. 2. The laser according to claim 1, wherein after the focusing operation is performed, a laser beam for processing is transmitted through the composite optical fiber, and the workpiece is irradiated with the laser beam for processing, thereby processing the workpiece. Laser processing method using a processing apparatus.

Images