JP2011235347A - Alignment regulation method, alignment regulation device, and laser beam machining device equipped with the alignment regulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alignment regulation device capable of position-aligning precisely and easily a focal point of a laser beam with respect to an axis of a liquid jet flow, in a laser beam machining device.SOLUTION: The alignment regulation device 10 includes a relative moving mechanism 34 for moving relatively a jet nozzle 20 and an optical fiber 22, an imaging means 37 for photographing an image Q of an inlet opening part 20a of the jet nozzle 20 and an image R of a laser image, and an alignment control means for controlling the relative moving mechanism 34, based on the images Q, R, and the alignment control means is constituted to execute (a) a step of finding the center of the inlet opening part 20a, based on the image Q, (b) a step of finding the center of the laser image, based on the image R, and (c) a step of moving the optical fiber 22 with respect to the jet nozzle 20, by driving the relative moving mechanism 34 so as to make the center of the laser image consistent with the center of the inlet opening part 20a.

Description

  The present invention relates to an alignment adjustment method, an alignment adjustment apparatus, and a laser processing apparatus including the alignment adjustment apparatus that align a laser focus of a laser processing apparatus that processes a workpiece with a laser guided by a liquid jet.

  In a laser processing apparatus that processes a workpiece by a laser guided by a liquid jet, it is important to align the laser irradiation optical axis with the axis of the liquid jet. This is because the focal position of the laser with respect to the liquid jet greatly affects the output of the laser, and thus greatly affects the laser processing capability. As a method of aligning the laser irradiation optical axis with the axis of the liquid jet, for example, there are methods described in Patent Document 1 and Patent Document 2. In the method described in Patent Document 1, a laser is irradiated into a liquid jet ejected from a nozzle, and a focal position of the laser is estimated from a missing direction of a laser image transmitted through a translucent plate arranged below the nozzle. The laser focus is positioned on the nozzle axis.

  In the method described in Patent Document 2, the intensity of the laser guided into the liquid jet is measured, and the nozzle is positioned with respect to the laser irradiation position so that the intensity of the laser is maximized.

  Further, in a laser processing apparatus that performs processing only by laser irradiation without using a liquid jet, for example, Patent Document 3 and Patent Document 4 describe a method for aligning a laser irradiation position with a workpiece or the like. There is a way to be. In the method described in Patent Document 3, the focal point of two spot lights is adjusted by moving a collimating lens in the optical axis direction in a laser processing apparatus that divides light from an optical fiber and emits two spot lights. can do. In addition, this laser processing apparatus is provided with a CCD camera for observing the irradiation areas of two spot lights, and the workpiece can be positioned while observing the irradiation areas of the spot lights with this CCD camera. .

  In the method described in Patent Document 4, a burn pattern is formed by irradiating a photosensitive plate arranged on a fixing jig with a laser, and the burn pattern is positioned at the center of the monitor while observing the burn pattern with a monitor of a TV camera. In addition, the fixing jig is positioned so that the spot diameter of the burn pattern is within the core diameter of the optical fiber. Thereafter, the optical fiber is attached to the fixing jig, and the optical fiber is positioned so that the optical fiber image taken by the TV camera is positioned at the center of the monitor.

JP 2009-262163 A JP 2007-61914 A JP 2001-79679 A JP-A-5-150145

However, in the method described in Patent Document 1, the focal position of the laser is not directly obtained from the position of the irradiation laser and the opening of the nozzle, but in the liquid column caused by the deviation of the position of the laser focus and the opening of the nozzle. Since the focal point of the laser is indirectly obtained from the missing direction of the laser image, it is difficult to make the focal point of the laser coincide with the center coordinate of the nozzle opening with high accuracy.
In the method described in Patent Document 2, the focus of the laser is aligned by measuring the intensity of the Raman scattered light of the laser guided into the liquid column, so that the focus of the laser is aligned with high accuracy. Is difficult. In addition, since the alignment is manually performed by an operator, the alignment operation takes time, and the adjustment accuracy varies depending on the operator, resulting in variations in laser output. Furthermore, in order to generate Raman scattered light in water, a strong laser output is required. Therefore, when irradiating a laser in the adjustment stage, there is a possibility that the laser is irradiated to the nozzle and damages the nozzle.

Further, in the method described in Patent Document 3, since alignment of the optical fiber and laser focusing are performed manually using a plurality of screws, the alignment operation takes time and high-accuracy alignment cannot be performed. .
In the method described in Patent Document 4, the laser burn pattern of the laser formed on the photosensitive plate is verified to determine the center of the laser, not the center of the laser itself, and the laser on the photosensitive plate is not determined. Since the optical fiber is attached after the alignment operation, an attachment error may occur at this time, the alignment between the optical fiber and the center of the laser is not accurate, and the laser cannot be aligned with high accuracy. In addition, the burn pattern must be repeatedly formed in order to obtain the center of the laser, which is time consuming and the alignment is inaccurate because these alignment operations are manual operations.

  In the first place, the laser processing apparatuses described in Patent Documents 3 and 4 are apparatuses that perform processing with the laser focused directly on the workpiece, so that the principle of the laser processing apparatus that guides the laser into the liquid column ejected from the nozzle is the principle. Is different. Therefore, it is not necessary to take into account the damage of the nozzle due to the laser, and it is only necessary to perform alignment only in the relationship between the laser and the workpiece, so that there is no problem like the laser processing apparatus that guides the laser to the liquid column.

  An object of the present invention is to provide an alignment adjustment method capable of easily and accurately aligning the focal point of a laser with a liquid jet in a laser processing apparatus that processes a workpiece by a laser guided by the liquid jet. An object of the present invention is to provide an alignment adjusting device and a laser processing apparatus including the alignment adjusting device.

  In order to achieve the above object, an alignment adjusting apparatus of the present invention has a jet nozzle that forms a liquid column by ejecting a liquid, and a laser optical system that focuses a laser beam from a laser light source in the liquid column. And an alignment adjusting device for aligning the focus of the laser, which is used in a laser processing apparatus for processing a workpiece by a laser guided into the liquid column, and the laser focus is set at the center of the inlet opening of the jet nozzle. The relative movement mechanism that relatively moves the focal point of the jet nozzle and the laser so that it can be aligned with the nozzle, and the image of the jet nozzle inlet opening and the weak laser image irradiated near the inlet opening Relative movement based on the image of the jet nozzle and the inlet opening of the jet nozzle and the image of the laser imaged by the imaging means Alignment control means for controlling the structure to move the focal point of the laser to the center of the inlet opening of the jet nozzle, the alignment control means a) based on the image of the inlet opening of the jet nozzle, Determining the center of the inlet opening; b) determining the center of the laser image based on the image of the laser image irradiated near the inlet opening of the jet nozzle; and c) determining the center of the laser image. A step of driving the relative movement mechanism to move the jet nozzle and the focal point of the laser relatively so as to coincide with the center of the inlet opening.

  In the present invention configured as described above, an image of the entrance opening of the jet nozzle and an image of the weak laser image irradiated near the entrance opening are captured by the image capturing means, and the alignment control means Based on the image, the center of the entrance opening and the center of the laser image are obtained. Then, the relative movement mechanism is controlled so that the center of these inlet openings and the center of the laser image coincide with each other to move the jet nozzle and the focal point of the laser relatively.

According to the present invention, since the inlet opening and the center of the laser are directly obtained based on the image of the inlet opening of the jet nozzle and the image of the image of the laser irradiated in the vicinity of the inlet opening, the inlet opening Since the position of the part and the position of the laser image itself can be directly compared, alignment can be performed with high accuracy.
In addition, the center of the entrance opening and the laser image are obtained, and the jet nozzle and the laser focus are moved relative to each other so that these centers coincide with each other. Since it is not necessary to repeat the operation of acquiring and comparing the image of the laser image again, the adjustment operation is performed in a short time. In addition, it is not necessary for the operator to manually perform the alignment operation, so that the operation time can be shortened and the alignment can be performed easily and with high accuracy. Thereby, the occurrence of variations in the adjustment position due to manual adjustment work by the operator is prevented, the output of the laser is stabilized, and the workability is stabilized.

Further, when obtaining an image of a laser image, a weak laser is irradiated near the inlet opening of the jet nozzle, so that it is possible to prevent damage to the jet nozzle due to laser irradiation during alignment adjustment. .
Here, the weak laser means a laser with an output that does not damage the jet nozzle. For example, a laser having a laser output lower than the laser output necessary for processing the material constituting the jet nozzle, or a laser It is set as a laser having a laser power lower than the laser power set for the processing device to process the workpiece.
Further, since the determination of the focal position of the laser and the movement control of the relative position between the focal point of the laser and the inlet opening of the jet nozzle are performed by the control of the alignment control means, there is no need for the operator to manually perform alignment. Therefore, the alignment adjustment work can be performed in a short time and easily, and the adjustment can be performed with higher accuracy than in the case where the adjustment is performed manually.

In the present invention, preferably, in step a), an image of the inlet opening including information on the center of the inlet opening of the jet nozzle is stored in advance, and the image of the inlet opening of the jet nozzle imaged by the imaging means Determining the center of the inlet opening by comparison;
In the present invention configured as described above, the center of the inlet opening of the jet nozzle is obtained by comparing a pre-registered image of the inlet opening with the captured image. The center can be obtained in a short time by a simple method.

In the present invention, preferably, the step b) classifies the image of the laser image into a region having a predetermined luminance or higher and a region having a predetermined luminance or lower, and obtaining a center of gravity of the region having the predetermined luminance or higher. Determining the center of the image of the laser.
In the present invention configured as described above, the center of the laser image is obtained by calculating the center of gravity of a region having a predetermined luminance or higher, so that the center of the laser image can be accurately obtained by a simple method. .

  In the present invention, preferably, it further has a power meter for measuring the output of the laser, and the alignment control means d) measures the output of the laser guided into the liquid column over a predetermined region with the power meter, and measures The step of setting the relative position of the jet nozzle and the focal point of the laser at a position where the output of the generated laser is maximized is further performed.

  In the present invention configured as described above, the relative position of the jet nozzle and the focal point of the laser is set at a position where the laser output measured by the power meter is maximized. It can be positioned at the inlet opening of the nozzle. In addition, since step d) is performed after the relative positions of the two are determined based on the inlet opening of the jet nozzle and the image of the laser, positioning with higher reliability is possible.

  In the present invention, preferably, the laser optical system includes an optical fiber that guides a laser beam emitted from a laser light source, a collimator lens that collimates the laser beam from the optical fiber, and a condensing beam that condenses the laser beam from the collimator lens. A relative movement mechanism configured to move the focal point of the laser with respect to the jet nozzle by moving the optical fiber, and further, the laser optical system is configured so that the moving distance of the optical fiber is a laser beam. It is comprised so that it may become larger than the movement distance of a focus.

In the present invention configured as above, the relative movement mechanism is configured to move the focal point of the laser relative to the jet nozzle by moving the optical fiber, so that the jet nozzle remains stationary. It becomes. Usually, a jet nozzle needs to support a mechanism for introducing a liquid for a liquid column and each component, and therefore, the weight may be larger than that of a laser optical system. Therefore, in the present invention, the stability of the laser processing apparatus can be improved by moving the focal point of the laser with respect to the jet nozzle. In addition, the relative movement mechanism is not configured to move the jet nozzle from which the liquid jet is ejected, but is configured to move the optical fiber of the laser optical system, so the relative movement mechanism is arranged at a position away from the jet nozzle. It is possible to prevent the liquid droplet from adhering to and entering the relative movement mechanism.
In addition, since the laser optical system is configured such that the optical fiber moving distance by the relative moving mechanism is larger than the moving distance of the laser focal point, even if the optical fiber moving distance by the relative moving mechanism is large, the laser is The moving distance of the focal point can be reduced. Thereby, the focal point of the laser can be precisely moved, and the position of the focal point of the laser can be adjusted with high accuracy.

In the present invention, preferably, the imaging means includes a CCD camera, illumination that illuminates the vicinity of the jet nozzle, a filter disposed in a central portion of light from the illumination, a collimating lens that guides light from the illumination to the vicinity of the jet nozzle, and A condensing lens and a monitor for displaying an image obtained by a CCD camera are provided.
In the present invention configured as described above, the image pickup means has a filter disposed in the central portion of the light from the illumination, so that unnecessary light reaching the CCD camera is removed from the central portion and a clear image is obtained. Can be obtained.

  In order to achieve the above object, the alignment adjustment method of the present invention includes a jet nozzle that ejects a liquid to form a liquid column, a laser light source that emits a laser, and a laser from a laser light source in the liquid column. An alignment adjustment method for aligning the focal point of a laser, which is used in a laser processing apparatus for processing a workpiece by a laser guided into a liquid column Obtaining an image of the inlet opening of the jet nozzle and determining the center of the inlet opening based on the image of the inlet opening; and B) irradiating a weak laser near the inlet opening of the jet nozzle. And obtaining the center of the laser image based on the laser image, and C) aligning the center of the laser image with the center of the entrance opening. As to, it is characterized by having a step of relatively moving the focal point of the jet nozzle and the laser, the.

According to the present invention, since the inlet opening and the center of the laser are directly obtained based on the image of the inlet opening of the jet nozzle and the image of the image of the laser irradiated in the vicinity of the inlet opening, the inlet opening Since the position of the part and the position of the laser image itself can be directly compared, alignment can be performed with high accuracy.
In addition, the center of the entrance opening and the laser image are obtained, and the jet nozzle and the laser focus are moved relative to each other so that these centers coincide with each other. Since it is not necessary to repeat the operation of acquiring and comparing the image of the laser image again, the adjustment operation is performed in a short time. In addition, it is not necessary for the operator to manually perform the alignment operation, so that the operation time can be shortened and the alignment can be performed easily and with high accuracy. Thereby, the occurrence of variations in the adjustment position due to manual adjustment work by the operator is prevented, the output of the laser is stabilized, and the workability is stabilized.
Further, when obtaining an image of a laser image, a weak laser is irradiated near the inlet opening of the jet nozzle, so that it is possible to prevent damage to the jet nozzle due to laser irradiation during alignment adjustment. .

In the present invention, preferably, in step A), an image of the inlet opening including information on the center of the inlet opening of the jet nozzle is stored in advance, and is compared with the image of the captured inlet opening of the jet nozzle. To obtain the center of the inlet opening.
In the present invention configured as described above, the center of the inlet opening of the jet nozzle is obtained by comparing a pre-registered image of the inlet opening with the captured image. The center can be obtained in a short time by a simple method.

In the present invention, preferably, the step B) classifies the image of the laser image into a region having a predetermined luminance or higher and a region having a lower luminance than the predetermined luminance, and obtaining the center of gravity of the region having the predetermined luminance or higher. Determining the center of the image of the laser.
In the present invention configured as described above, the center of the laser image is obtained by calculating the center of gravity of a region having a predetermined luminance or higher, so that the center of the laser image can be accurately obtained by a simple method. .

In the present invention, preferably, D) the output of the laser guided into the liquid column is measured over a predetermined region, and the relative position of the jet nozzle and the focal point of the laser is set at a position where the measured laser output is maximized. The method further includes the step of:
In the present invention configured as described above, the relative position of the jet nozzle and the laser focus is set at a position where the measured laser output is maximized, so that the laser focus can be adjusted to the entrance of the jet nozzle with higher accuracy. It can be positioned in the opening. In addition, since step D) is performed after the relative positions of the jet nozzle inlet opening and the laser image are positioned based on the image of the jet nozzle, positioning with higher reliability is possible.

  In the present invention, the laser passing through the laser optical system is preferably guided by an optical fiber from a laser light source, collimated by a collimating lens, and then condensed by a condenser lens, and step C) moves through the optical fiber. By doing so, the focal point of the laser is moved relative to the jet nozzle, and the moving distance of the optical fiber is configured to be larger than the moving distance of the focal point of the laser.

In the present invention thus configured, the focal point of the laser is moved relative to the jet nozzle by moving the optical fiber, so that the jet nozzle remains stationary. Usually, a jet nozzle needs to support a mechanism for introducing a liquid for a liquid column and each component, and therefore, the weight may be larger than that of a laser optical system. Therefore, in the present invention, the stability of the laser processing apparatus can be improved by moving the focal point of the laser with respect to the jet nozzle. Also, instead of moving the jet nozzle that ejects the liquid jet to move the focal point of the laser, the optical fiber of the laser optical system is moved, so the focal point of the laser is moved away from the jet nozzle. Therefore, it is possible to reliably prevent adhesion, intrusion, and the like of droplets to the relative movement mechanism.
Further, since the moving distance of the optical fiber is configured to be larger than the moving distance of the focal point of the laser, the moving distance of the focal point of the laser can be reduced even if the moving distance of the optical fiber is increased. Thereby, the focal point of the laser can be precisely moved, and the position of the focal point of the laser can be adjusted with high accuracy.

In the present invention, preferably in steps A) and B), an image of the entrance opening or of the laser image is obtained by illuminating the vicinity of the jet nozzle with illumination in which the central part of the light is covered by a filter.
In the present invention configured as described above, unnecessary light from the central portion is removed by the filter disposed in the central portion of the light from the illumination, so that a clear image can be obtained.

In order to achieve the above object, a laser processing apparatus of the present invention is a laser processing apparatus that processes a workpiece by a laser guided by a liquid jet, and forms a liquid column by ejecting liquid. It is characterized by comprising a jet nozzle, a laser optical system for condensing a laser beam in the liquid column, and the alignment adjusting device described above.
According to the present invention, since the laser processing apparatus includes the above-described alignment adjustment device, the same effect as the above-described effect of the alignment adjustment device can be obtained. That is, since the inlet opening and the center of the laser are obtained directly based on the image of the inlet opening of the jet nozzle and the image of the laser image irradiated near the inlet opening, the position of the inlet opening and the image of the laser are obtained. Since the positions themselves can be directly compared and aligned, high-accuracy alignment is possible.
In addition, the center of the entrance opening and the laser image are obtained, and the jet nozzle and the laser focus are moved relative to each other so that these centers coincide with each other. Since it is not necessary to repeat the operation of acquiring and comparing the image of the laser image again, the adjustment operation is performed in a short time. In addition, it is not necessary for the operator to manually perform the alignment operation, so that the operation time can be shortened and the alignment can be performed easily and with high accuracy. Thereby, the occurrence of variations in the adjustment position due to manual adjustment work by the operator is prevented, the output of the laser is stabilized, and the workability is stabilized.

Further, when obtaining an image of a laser image, a weak laser is irradiated near the inlet opening of the jet nozzle, so that it is possible to prevent damage to the jet nozzle due to laser irradiation during alignment adjustment. .
Further, since the determination of the focal position of the laser and the movement control of the relative position between the focal point of the laser and the inlet opening of the jet nozzle are performed by the control of the alignment control means, there is no need for the operator to manually perform alignment. Therefore, the alignment adjustment work can be performed in a short time and easily, and the adjustment can be performed with higher accuracy than in the case where the adjustment is performed manually.

It is a figure which shows roughly the structure of the laser processing apparatus by one Embodiment of this invention. It is a figure which shows the filter of the alignment adjustment apparatus by one Embodiment of this invention. It is a figure which shows the method of calculating | requiring the center of the inlet opening part of a jet nozzle in the alignment adjustment apparatus by one Embodiment of this invention. It is a figure which shows the image of the image of the laser shown with the inlet opening part of a jet nozzle in the alignment adjustment apparatus by one Embodiment of this invention. It is a figure which shows distribution of the brightness | luminance of the image of a laser in the alignment adjustment apparatus by one Embodiment of this invention. It is a figure which shows the method of calculating | requiring the center of the image of a laser in the alignment adjustment apparatus by one Embodiment of this invention. In the alignment adjustment apparatus by one Embodiment of this invention, it is a figure which shows the example of the relationship between the movement amount of a laser focus, and a laser output. It is a figure which shows the example of the adjustment result by the alignment adjustment apparatus by one Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram schematically showing the structure of a laser processing apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, a laser processing apparatus 1 in this embodiment includes a laser processing head 2, a laser optical system 4 for condensing a laser beam at a predetermined position in the laser processing head 2, and the laser optical system. 4 includes a laser light source 6 that causes a laser to enter the laser beam 4 and a pressure pump 8 that sends high-pressure water to the laser processing head 2.
The laser processing apparatus 1 also includes an alignment adjustment apparatus 10 for aligning the focal point of the laser emitted from the laser optical system 4. Furthermore, the laser processing apparatus 1 includes a personal computer 14 as a controller that controls the laser light source 6, the pressure pump 8, and the alignment adjustment apparatus 10. The personal computer 14 is provided with a monitor 16.

Further, the laser processing head 2 includes a head main body 18 and a jet nozzle 20 attached to the head main body 18.
The head main body 18 has a liquid supply chamber 18a formed therein, and a liquid supply passage 18b is formed so as to communicate with the liquid supply chamber 18a. A jet nozzle 20 is disposed at the bottom of the liquid supply chamber 18a. Further, a window member 18 c for transmitting the laser emitted from the laser optical system 4 and guiding it to the inlet opening 20 a of the jet nozzle 20 is attached to the upper end of the liquid supply chamber 18 a. The water sent from the pressurizing pump 8 flows into the liquid supply chamber 18a through the liquid supply passage 18b and is ejected from the jet nozzle 20.

  The jet nozzle 20 is a substantially cylindrical member, and a nozzle hole directed in the vertical direction is formed on the central axis thereof. The nozzle hole is composed of a cylindrical portion having a small diameter and extending in a cylindrical shape, and a conical portion connected to the cylindrical portion and having a diameter expanded toward the downstream side. The upper end surface of the nozzle hole that opens to the upper end surface 35 of the jet nozzle 20 is a circular inlet opening 20a through which the liquid enters the nozzle hole.

  The laser optical system 4 is configured to guide the laser emitted from the laser light source 6 to the laser processing head 2 and to condense the laser onto the inlet opening 20 a of the jet nozzle 20. The laser focused on the inlet opening 20a of the jet nozzle 20 by the laser optical system 4 repeats total reflection in the water column (liquid column) ejected from the jet nozzle 20, and the workpiece (not shown) is processed by the water column. Led up to.

  Specifically, the laser optical system 4 includes an optical fiber 22 that guides the laser emitted from the laser light source 6, a collimator lens 24 that collimates the laser emitted downward from the optical fiber 22 in the vertical direction, and a collimator lens. An aperture member 26 that restricts the amount of laser passing through the aperture 24, a mirror 28 that reflects the laser that has passed through the aperture member 26, and a mirror 30 that is provided in parallel with the mirror 28 and reflects the laser reflected by the mirror 28 again. And a condensing lens 32 for condensing the laser at the inlet opening 20a of the jet nozzle 20. The mirrors 28 and 30 are total reflection mirrors and are provided with a transmission preventing coating. The collimating lens 24 and the condenser lens 32 are provided with an antireflection coating.

  In the present embodiment, the mirror 28 is disposed at an angle of 45 ° with respect to the optical axis A of the laser exiting the optical fiber 22. With this arrangement, the laser exiting the optical fiber 22 downward in the vertical direction is Reflected in the horizontal direction at an angle of 90 ° by the mirror 28. Further, the mirror 30 is arranged at an angle of 45 ° with respect to the optical axis B of the laser focused on the inlet opening 20a of the jet nozzle 20, and this arrangement allows the laser that has entered the horizontal direction again. Reflects at an angle of 90 ° and faces downward in the vertical direction. In the present embodiment, the mirror 28 and the mirror 30 position the optical axis A parallel to the optical axis B and away from the optical axis B. With such a configuration, a space above the laser processing head 2 can be made, and the alignment adjusting device 10 can be arranged in this space.

  The laser light source 6 is configured to generate a laser having a predetermined intensity based on a control signal from the personal computer 14. In this embodiment, a green laser having a wavelength of 532 nm, which is a second harmonic of a YAG laser, is used as the laser. As the laser, other wavelength lasers may be used as long as they are in the green wavelength band, and lasers of any wavelength can be used as long as they are suitable for use in laser processing equipment. May be used.

  The pressurizing pump 8 is configured to pressurize water to a predetermined pressure based on a control signal from the personal computer 14 and flow the water into the head main body 18 of the laser processing head 2. The water fed into the head main body 18 is ejected from the jet nozzle 20 to form a water column.

  The personal computer 14 is configured to operate the laser light source 6, the pressure pump 8, and the relative movement mechanism 12 so as to perform alignment of the focal point of the laser or to process a workpiece. Specifically, the personal computer 14 includes an input / output interface for various signals, a memory, a microprocessor, a program for operating these, and the like. Further, the personal computer 14 functions as an alignment control means for controlling the operation of the alignment adjusting device 10 when performing the alignment of the laser focus.

  The alignment adjustment apparatus 10 is attached to the optical fiber 22, and moves relative to the optical fiber 22, an imaging unit 37 that captures an image of the upper end surface 35 of the jet nozzle 20, and the liquid emitted from the jet nozzle 20. The power meter 40 for measuring the output of the laser guided into the column, the relative movement mechanism 34, the CCD camera 36, and the personal computer 14 connected to the power meter 40 are configured. The imaging means 37 includes a CCD camera 36, an alignment collimator lens 38, and the above-described condenser lens 32.

The relative movement mechanism 34 includes a Z-axis motor (not shown) for moving the optical fiber 22 in the direction of the optical axis A (Z-axis direction) and a plane (XY plane) orthogonal to the optical axis A. An X-axis motor and a Y-axis motor (both not shown) for movement are provided, and the optical fiber 22 is configured to be movable in the XYZ axis directions by these XYZ axis motors. When the optical fiber 22 moves, the focal position of the laser in the laser processing head 2 moves accordingly. In the present embodiment, the relative movement mechanism 34 is configured to be able to adjust the position of the optical fiber 22 with an accuracy of 1 μm.
The relative movement mechanism 34 is controlled by a control signal from the personal computer 14 and is configured to move the focal point of the laser to a predetermined target focal position. In the present embodiment, the predetermined target focal position is set at the center of the inlet opening 20 a of the jet nozzle 20.

  The CCD camera 36 is disposed on the optical axis B above the laser processing head 2 and is configured to image the upper end surface 35 of the jet nozzle 20 including the inlet opening 20a. The CCD camera 36 is provided with illumination for imaging (not shown), and red illumination is used as the illumination. Here, since a green laser is employed as the laser in the present embodiment, the mirror 30 is set to have a high reflectance with respect to green light. For this reason, the mirror 30 has a high transmittance for red light. Therefore, the transmittance at the mirror 30 can be increased by using red illumination.

  Moreover, the filter 42 (FIG. 2) which covers the center part of illumination is provided in illumination. As shown in FIG. 2, the filter 42 includes an annular frame portion 42a attached to the illumination, and a circular filter portion 42b disposed inside the frame portion 42a and connected to the frame portion 42a by a plurality of connecting portions. Have.

The alignment collimator lens 38 is disposed between the mirror 30 and the CCD camera 36 on the optical axis B, and is provided with an antireflection coating.
The power meter 40 is arranged below the laser processing head 2 and is configured to measure the output of the laser guided into the liquid column ejected from the jet nozzle 20. Since the sprayed liquid column is applied to the power meter 40, the power meter 40 is waterproofed.

Next, an alignment adjustment method for aligning the focal point of the laser with the center of the inlet opening 20a of the jet nozzle 20 using the alignment adjustment apparatus 10 of the laser processing apparatus 1 of the present embodiment configured as described above will be described. This will be described below with reference to FIGS.
The alignment adjustment method roughly performs a rough adjustment to align the focal point of the laser and the center of the inlet opening 20a of the jet nozzle 20 based on the image picked up by the image pickup means 37, and uses the power meter 40 to adjust both. Fine adjustment for alignment is performed, and then alignment confirmation is performed to confirm whether alignment adjustment is properly performed, and output confirmation is performed to confirm whether a desired output is obtained.

First, the focus of the laser is aligned with the center of the inlet opening 20a of the jet nozzle 20 by coarse adjustment.
First, the center of the inlet opening 20a of the jet nozzle 20 is obtained. FIG. 3 shows a method for obtaining the center of the inlet opening 20a of the jet nozzle 20 by the alignment adjusting apparatus 10 of the present embodiment. As shown in FIG. 3A, an image P of the inlet opening 20a of the jet nozzle 20 is registered in the personal computer 14 in advance. The center P1 is set in advance for the image P, and information about the center P1 is also registered in the personal computer 14 together with the image P.

Next, an image Q of the inlet opening 20 a of the jet nozzle 20 is taken by the CCD camera 36. FIG. 3B shows an image Q of the inlet opening 20 a of the jet nozzle 20. As shown in FIG. 3B, in the image Q displayed on the monitor 16, the entire upper end surface 35 of the jet nozzle 20 is displayed relatively brightly, and the portion corresponding to the inlet opening 20a is relatively dark and circular. Is displayed.
The personal computer 14 compares this image Q with the image P, and searches for a point where the registered image P and the shape of the entrance opening 20a of the captured image Q match, as shown in FIG. The coordinates of the center P1 of the image P at the point are detected as the center coordinates of the entrance opening 20a, and the coordinate position is stored.

Next, the alignment adjustment apparatus 10 obtains the center of the image of the laser irradiated near the entrance opening 20 a of the upper end surface 35 of the jet nozzle 20.
First, the pressurizing pump 8 is operated to supply water to the liquid supply chamber 18 a through the liquid supply passage 18 b, and a water column is ejected from the jet nozzle 20. Further, a weak laser output for the first alignment is emitted from the laser light source 6. The first alignment output is selected so as not to damage the jet nozzle 20 even when the laser is irradiated onto the upper end surface 35 of the jet nozzle 20. In the present embodiment, the first alignment output is set to 0.01 W or less.
The laser emitted from the laser light source 6 passes through the optical fiber 22, the collimator lens 24, the aperture member 26, the mirrors 28 and 30, and the condenser lens 32, and is condensed near the inlet opening 20 a of the jet nozzle 20.

  The CCD camera 36 captures an image of the laser irradiated on the upper end surface 35 of the jet nozzle 20. FIG. 4 shows an image R obtained by capturing a laser image with the CCD camera 36 in the alignment adjusting apparatus 10 according to the present embodiment. In FIG. 4, the inlet opening 20a of the jet nozzle 20 is displayed in a relatively dark region R1, and the laser image is displayed in a relatively bright region R2.

  Next, the personal computer 14 estimates the center of the laser image from the image R. FIG. 5 is a diagram showing the luminance distribution of the laser image R in the alignment adjusting apparatus 10 according to the present embodiment. As shown in FIG. 5, the luminance is concentrated in a certain range, and the luminance distribution larger than that is small. Here, the area | region which has the brightness | luminance of the concentrated range is an area | region of the upper end surface 35 of the jet nozzle 20, and the entrance opening part 20a, and it is thought that the image of a laser has a bigger brightness | luminance than it. Therefore, the personal computer 14 sets a luminance larger than the luminance in the concentrated range as a threshold for binarization, and sets the laser image R to 0 when the luminance is less than the binarization threshold. If it is equal to or greater than the threshold for use, a binarization process of 1 is performed. Various values can be adopted as the binarization threshold depending on the measurement conditions and the calculation processing conditions. In this embodiment, 90% of the detected maximum luminance value is set as the binarization threshold. is doing. When such binarization processing is displayed on the monitor 16, as shown in FIG. 5, an area having a luminance equal to or higher than the binarization threshold is set to 1 and displayed on the monitor 16 in white and binarized. An area having a luminance less than the threshold for use is set to 0 and displayed on the monitor 16 in black.

  FIG. 6 is a diagram illustrating a method of obtaining the laser image center of the image R in the alignment adjustment apparatus 10 according to the present embodiment. As shown in FIG. 6A, when the laser image R is binarized and displayed in black and white, only the region R3 corresponding to the laser image is displayed in white. The personal computer 14 calculates the coordinates of the center R4 of the laser image as shown in FIG. 6B by obtaining the center of gravity of the white region R3.

Next, the personal computer 14 compares the coordinates of the center R4 of the laser image with the coordinates of the center of the inlet opening 20a of the jet nozzle 20, calculates the deviation of these coordinates, and corresponds to the deviation of the coordinates. The amount of movement of the optical fiber 22 is calculated. Then, a movement signal corresponding to the required movement amount of the optical fiber 22 is transmitted to the relative movement mechanism 34. The relative movement mechanism 34 drives the X-axis motor and the Y-axis motor to move the optical fiber 22 in the XY plane, whereby the center R4 of the laser image is located at the entrance opening 20a of the jet nozzle 20. Match the center.
Through the adjustment procedure as described above, rough adjustment between the center of the inlet opening 20a of the jet nozzle 20 and the focal point of the laser is completed.

Next, the fine adjustment of the alignment between the center of the inlet opening 20a of the jet nozzle 20 and the focal point of the laser will be described.
First, the laser light source 6 emits a weak laser for second alignment. Here, the second alignment output is set to an output that is higher than the first alignment output and does not damage the jet nozzle 20 but can propagate the laser beam in the water column. In the present embodiment, the second alignment output is set to 0.5 to 2 W. As described above, the first and second alignment outputs are set to outputs that do not damage the jet nozzle 20.

  Here, the weak laser means a laser emitted with an output that does not damage the jet nozzle 20 even when irradiated to the jet nozzle 20. For example, a laser necessary for processing a material constituting the jet nozzle It is set as a laser having a laser output lower than the output or a laser having a laser output lower than the laser output set for processing the workpiece by the laser processing apparatus. The output of such a laser is preferably set to 2 W or less depending on the material of the jet nozzle 20.

  The personal computer 14 drives the Z-axis motor of the relative movement mechanism 34 to move the optical fiber 22 in the Z-axis direction by a predetermined distance (for example, 400 μm), and in the water column ejected from the jet nozzle 20 at each movement position. The power output of the laser is measured by the power meter 40. In this embodiment, the focal position of the laser after coarse adjustment is used as a measurement start point, a predetermined distance (for example, 400 μm) is set as one step, and each step is moved 10 steps upward and downward along the Z axis from the start point. Together with the measurement at the starting point, the laser output is measured at a total of 21 locations. Therefore, in this embodiment, the power meter 40 measures the output of the laser over a linear region along the Z axis a plurality of times (21 times).

  Here, the amount of movement of the optical fiber 22 in the Z-axis direction and the amount of movement of the laser focus in the Z-axis direction are inversely proportional to the focal length of the laser optical system. That is, generally, when the object point distance from the object point to the lens is a and the image point distance from the lens to the image point is b, the focal length f of the entire laser optical system is approximately expressed by the following equation. expressed.

  In the present embodiment, the moving distance of the laser focal point is calculated using the above approximate expression. That is, in this embodiment, the object point distance a corresponds to the focal length of the collimating lens 24, and this focal length is set to 400 mm. The image point distance b corresponds to the focal length of the condenser lens 32, and this focal length is set to 60 mm. Therefore, when the above approximate expression is used, the focal length f of the entire laser optical system 4 is about 52.17 mm. If the same laser optical system is used, the focal length f of the entire laser optical system 4 does not change. Therefore, if the focal length a ′ of the collimating lens 24 changes due to the movement of the optical fiber 22 in the Z-axis direction, condensing is performed accordingly. The focal length b ′ of the lens 32 also changes. Specifically, when the optical fiber 22 is moved upward by 400 μm along the Z axis, the focal point of the laser moves upward by about 10 μm. As described above, in the present embodiment, the focal length of the laser optical system 4 is set so that the movement distance of the optical fiber 22 in the Z-axis direction is larger than the movement distance of the laser focus in the Z-axis direction. Has been.

  FIG. 7 is a diagram illustrating an example of the relationship between the laser focus movement amount (that is, the movement amount of the optical fiber 22) and the laser output in the alignment adjustment apparatus 10 according to the present embodiment. As shown in FIG. 7C, the output of the laser changes at each movement position in the Z-axis direction. The personal computer 14 calculates the Z-axis coordinate of the position where the laser output is maximum among these laser outputs. Then, a coordinate shift between the Z-axis coordinate and the measurement start point is calculated, and the coordinate shift is converted into a moving amount of the optical fiber 22 so that the focal point of the laser is located at the Z-axis coordinate. The optical fiber 22 is moved.

Next, the X-axis motor and the Y-axis motor of the relative movement mechanism 34 are driven to move the optical fiber 22 by a predetermined distance in the X-axis and Y-axis directions, and the laser output is measured at each moving position. Measure at 40. In the present embodiment, the measurement is performed by moving the measurement start point and 10 steps from the start point along the X-axis and the Y-axis by a predetermined distance in each direction (for example, 10 μm) for 10 steps. Measure.
Here, the amount of movement of the optical fiber 22 in the X-axis and Y-axis directions and the amount of movement of the laser focus in the X-axis and Y-axis directions are proportional to the magnification of the lens. In this embodiment, since the focal length of the collimating lens 24 is 400 mm and the focal length of the condensing lens 32 is 60 mm, the magnification is 0.15. Therefore, the optical fiber 22 is aligned along the X axis or the Y axis. When moved 10 μm in one direction, the focal point of the laser moves about 1.5 μm in the direction opposite to the moving direction of the optical fiber 22. As described above, in this embodiment, the magnification of the lens of the laser optical system 4 is such that the movement distance of the optical fiber 22 in the X axis and Y axis is greater than the movement distance of the laser focus in the X axis and Y axis directions. Is also set to be large.

As shown in FIGS. 7A and 7B, the laser output changes at each movement position. The personal computer 14 calculates the peak values of the laser output at the total 21 locations of the obtained X axis and Y axis, respectively, and the X axis coordinates so that the laser focus is located at the X coordinates and Y coordinates at the peak values. And determine the Y-axis coordinates. Then, the deviation of the coordinates between the X-axis coordinates and the Y-axis coordinates and the measurement start point is calculated, and the deviation of the coordinates is converted into the movement amount of the optical fiber 22, and the focal point of the laser is changed to the X-axis coordinates and The relative movement mechanism 34 is driven to move the optical fiber 22 so as to be positioned at the Y-axis coordinates.
The fine adjustment of the alignment between the center of the inlet opening 20a of the jet nozzle 20 and the focal point of the laser is completed by the adjustment operation as described above.

  Next, alignment confirmation for confirming whether the alignment adjustment is appropriate is performed in a state where the center of the inlet opening 20a of the jet nozzle 20 and the focal point of the laser are aligned by the method described above.

  In a state where the fine adjustment of the alignment between the center of the inlet opening 20a of the jet nozzle 20 and the focal point of the laser has been completed, the laser light source 6 raises the laser output and emits an alignment confirmation output laser. Here, the alignment confirmation output is larger than the first and second alignment outputs, but is set smaller than the output used in actual laser processing, for example, about 5 to 12.5 W. By setting the alignment confirmation output to be larger than the first and second alignment outputs, the difference between the outputs that may be difficult to confirm with the weak laser at the first and second alignment outputs is greater. Because it becomes clear, more accurate output is obtained. Further, by setting the output for alignment confirmation to be smaller than the output used during actual laser processing, damage to the jet nozzle 20 by the laser during the alignment confirmation work can be minimized.

The power meter 40 measures the output of the laser guided to the water column and transmits this measurement data to the personal computer 14. The personal computer 14 compares the laser output with a preset alignment confirmation output threshold value, and determines whether the laser output has reached the alignment confirmation output threshold value. The alignment confirmation output threshold value is set in consideration of output loss in the laser optical system 4, and is set to about 5 to 10 W, for example, in the present embodiment.
If the laser output has reached the alignment confirmation output threshold, the alignment adjustment is completed, assuming that the alignment adjustment has been completed. On the other hand, if the laser output has not reached the alignment confirmation output threshold, the optical fiber 22 is moved again to the XYZ axes, and the laser output is measured by the power meter 40. Fine adjustment is performed to move the optical fiber 22 so that the focal point of the laser is positioned at the position.

When the alignment confirmation is completed, the personal computer 14 next performs output confirmation for confirming whether the laser guided to the water column from the jet nozzle 20 has a desired output.
First, in the laser light source 6, the output of the laser is increased, and an output confirmation output laser is emitted. Here, the output confirmation output is larger than the first and second alignment outputs, and is set to about the output used during actual laser processing. The output confirmation output is determined according to the material and thickness of the workpiece. For example, when using SUS304 and the thickness t = 0.1 mm as the material of the workpiece, the output is about 10 to 19 W. Is set. The power meter 40 measures the output of the laser guided into the water column and transmits this measurement data to the personal computer 14. The personal computer 14 compares the laser output with a preset output threshold value, and determines whether the laser output has reached the output threshold value. The output threshold value is set in consideration of the output loss in the laser optical system 4 and the like, and in this embodiment, for example, 10 to 15 W, preferably around 13 W is set as a guide.

  If the laser output has reached the output threshold value, the personal computer 14 determines that the alignment adjustment has been performed appropriately, and completes the alignment adjustment operation. On the other hand, if the laser output has not reached the output threshold, the optical fiber 22 is moved again to the XYZ axes, the laser output is measured by the power meter 40, and the position where the laser output is maximized. Fine adjustment is performed to move the optical fiber 22 so that the focal point of the laser is located at the center.

  FIG. 8 is a diagram illustrating an example of an adjustment result by the alignment adjustment apparatus 10 according to the present embodiment. In FIG. 8, the alignment adjustment apparatus 10 of the laser processing apparatus 1 according to the present embodiment is repeatedly operated to perform alignment adjustment four times, and the deviation of the coordinates of each axis after each adjustment from the first coordinate is shown. . As shown in FIG. 8, in each of the XYZ axes, the error in the coordinates of each time remains in the μm range, and thus it can be seen that the adjustment reproducibility of the alignment adjustment apparatus 10 according to the present embodiment is very high.

According to the present embodiment configured as described above, the following excellent effects can be obtained.
The alignment adjustment device 10 aligns the focal point of the laser at the center of the inlet opening 20a based on the image P of the inlet opening 20a of the jet nozzle 20 and the image R of the laser image. The alignment adjustment can be performed using the actual position information of the laser image. Therefore, alignment adjustment can be performed with high accuracy.
In addition, since the alignment adjustment operation, that is, the calculation of the focal position of the laser and the movement control of the optical fiber 22 are performed by the control of the personal computer 14, it is not necessary for the operator to perform the alignment manually. Therefore, the alignment adjustment work can be performed in a short time and easily, and the adjustment can be performed with higher accuracy than in the case where the adjustment is performed manually. As a result, the occurrence of variations in the adjustment position by the operator can be prevented, the reproducibility of the adjustment position can be improved, and a stable laser output can be obtained by preventing variations in the adjustment position. And stable laser processing can be performed.

  Since the laser irradiated during the alignment adjustment operation is emitted with weak first and second alignment outputs, the laser is irradiated onto the upper end surface 35 of the jet nozzle 20 in a state where the alignment is not adjusted, and the jet nozzle 20 Can be prevented from being damaged.

When determining the center of the inlet opening 20a of the jet nozzle 20, the image P of the jet nozzle 20 is registered in advance together with the information on the center position, and the image Q of the inlet opening 20a captured by the CCD camera 36 is obtained. By comparing, the coordinates of the center of the inlet opening 20a are obtained. Therefore, the center coordinates of the inlet opening 20a can be obtained in a short time by a simple method.
Further, the center coordinates of the image R of the laser image and the center coordinates of the image Q of the entrance opening are respectively obtained, and the focal position of the laser is moved to the center coordinates of the entrance opening. There is no need to capture and compare the image Q of the inlet opening. Therefore, the alignment operation of the laser focus can be performed easily and in a short time.

  When determining the center of the image of the laser, 90% of the maximum luminance value of the image R is set as a threshold value, and the image R is binarized into an image area above and below this threshold value. Processing is performed to determine the center of the laser image by determining the center of gravity of the image area above the threshold. Thus, since alignment adjustment is performed by simple image analysis by binarization processing, the center of the laser can be obtained in a short time.

After coarse adjustment of the laser focus by analyzing the images Q and R, the laser output is measured using the power meter 40, and the laser focus position is moved so that the laser output is maximized. The focus position can be further finely adjusted, and alignment adjustment can be performed with higher accuracy.
In addition, since the power meter 40 measures the output of the laser guided into the water column, the laser needs a certain level of output in order to guide the laser into the water column. At this time, after the laser focus is roughly adjusted by analyzing the images Q and R, fine adjustment by the power meter 40 is performed, so that the laser can surely enter the entrance opening 20a, and the jet nozzle 20 is damaged. Can reduce the risk.

Here, in the actual laser processing apparatus 1, at the position where the center of the laser focus coincides with the center of the inlet opening 20a of the jet nozzle 20, the output of the laser guided into the water is not always the maximum. . Therefore, in this embodiment, the laser focus is finely adjusted using the power meter 40 after the coarse adjustment of the laser focus by the analysis of the images Q and R, so that the laser beam is adjusted according to the actual state of the laser processing apparatus 1. The focus of the laser can be aligned at a position where the laser output is maximized.
In addition, the center of the laser focus is made to coincide with the center of the inlet opening 20a of the jet nozzle 20 by rough adjustment, and the position is set as the measurement start point at the time of fine adjustment. The laser output can be measured by moving the focal point. That is, during fine adjustment, it is not necessary to measure the laser output with the power meter 40 over the entire range of the inlet opening 20a, and only the vicinity of the center of the inlet opening 20a may be measured. Therefore, the adjustment time for fine adjustment using the power meter 40 can be shortened.

Since the relative movement mechanism 34 is provided in the optical fiber 22 and the optical fiber 22 is configured to move relative to the laser processing head 2, it is not necessary to move the laser processing head 2. Since the laser processing head 2 has the liquid supply space 18b and is also connected to a high-pressure water pipe or the like, the weight is often heavier than the structure supporting the optical fiber 22. Therefore, the mechanical stability of the laser processing apparatus 1 can be ensured by attaching the relative movement mechanism 34 to the optical fiber 22 having a lighter weight.
In addition, various structural components such as the pressurizing pump 8 are often arranged around the laser processing head 2, and it is difficult to secure a space for the relative movement mechanism 34. In the present embodiment, since the relative movement mechanism 34 is attached to the optical fiber 22, it is easy to secure a space for the relative movement mechanism 34 and the design of the laser processing apparatus 1 is facilitated.

  Since the relative movement mechanism 34 is attached to the optical fiber 22, it is possible to dispose a structural component such as an XYZ-axis motor or the like that needs to reliably prevent liquid adhesion and penetration from the laser processing head 2. . Therefore, it is possible to easily take a waterproof measure necessary for the relative movement mechanism 34.

  Since the laser optical system 4 is set so that the movement distance of the optical fiber 22 in the XYZ-axis direction is larger than the movement distance of the laser focus in the XYZ-axis direction, the focal point of the laser with respect to the movement distance of the optical fiber 22 is set. Can be moved by a short distance. Therefore, the position of the focal point of the laser can be controlled with high accuracy with respect to the movement accuracy of the optical fiber 22. On the other hand, since the movement accuracy of the relative movement mechanism 34 can be made relatively coarse with respect to the required movement accuracy of the focal point of the laser, the movement accuracy required for the relative movement mechanism 34 becomes relatively low. The configuration of the moving mechanism 34 can be designed easily and inexpensively.

  Since the central part of the illumination of the CCD camera 36 is covered with the filter 42, unnecessary light components can be removed by the filter 42, and a clear image can be obtained in the CCD camera 36. That is, several percent of the illumination light emitted from the illumination is reflected by the alignment collimating lens 38 and the condenser lens 32. At this time, since the reflected light of the light irradiated from the central portion of the illumination is reflected directly toward the CCD camera 36, when the reflected light is received by the CCD camera 36, an image of the inlet opening 20a of the jet nozzle 20 is received. Contains a bright component (bias component) as a whole, and the contrast of the image becomes weak. In the present embodiment, since the filter 42 is provided, this bias component can be removed, and clear images Q and R can be obtained.

The present invention is not limited to the above-described embodiment. For example, the method for obtaining the center of the inlet opening of a jet nozzle is the same as the above-described embodiment in which an image of a pre-registered inlet opening is captured. Although it compared with the image of an opening part, it is not restricted to this, For example, the image of an entrance opening part may be binarized and the center of an entrance opening part may be calculated | required similarly to the method of calculating | requiring the center of the image of a laser.
Further, when aligning the inlet opening of the jet nozzle and the center of the laser, in the above-described embodiment, the coarse adjustment is performed only in the XY-axis direction. Further, the Z-axis direction may be adjusted in consideration of the size of the laser image.

When the laser output is measured by the power meter, the laser output is measured at predetermined distances a plurality of times in the above-described embodiment. However, the present invention is not limited to this. For example, the laser power is moved while moving the laser focus. The output may be measured continuously.
In the above-described embodiment, the laser output is measured over a linear region in each direction of the XYZ axes. However, the present invention is not limited to this. For example, the laser focus is moved over a two-dimensional region of XY. The laser output may be measured.
In addition, the method of measuring the laser output with a power meter and aligning the focal point of the laser is not always necessary. For example, it is sufficient to align the inlet opening of the jet nozzle and the center of the laser based on the image. When adjustment accuracy can be obtained, the laser output may not be finely adjusted by measuring the laser output with a power meter.

In the above-described embodiment, the laser optical system is configured to include the optical fiber 22, the collimating lens 24, the aperture member 26, the mirrors 28 and 30, and the condensing lens 32. However, the laser optical system is not limited to such a configuration. If it is configured to propagate to the jet nozzle emitted from the light source, the configuration, arrangement, etc. of the members can be arbitrarily set.
Further, the relative movement mechanism is not limited to one that moves the optical fiber, and the configuration thereof is arbitrary as long as the focal point of the laser is moved relative to the jet nozzle. In addition, the relative movement mechanism is not limited to the configuration in which the focal point of the laser is moved relative to the jet nozzle, and may be configured to move the jet nozzle relative to the focal point of the laser.

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 6 Laser light source 10 Alignment adjustment apparatus 14 Personal computer 16 Monitor 20 Jet nozzle 20a Entrance opening part 32 Condensing lens 34 Relative movement mechanism 36 CCD camera 38 Collimating lens 40 for alignment Power meter 42 Filter

Claims (13)

It has a jet nozzle that ejects liquid to form a liquid column, and a laser optical system that condenses the laser from the laser light source in the liquid column, and the workpiece is processed by the laser guided into the liquid column. An alignment adjusting device used for a laser processing apparatus for aligning the focal point of the laser,
A relative movement mechanism for relatively moving the jet nozzle and the laser focus so that the focus of the laser can be aligned with the center of the inlet opening of the jet nozzle;
An imaging means for capturing an image of the inlet opening of the jet nozzle and an image of a weak laser image irradiated near the inlet opening;
The relative movement mechanism is controlled on the basis of the inlet opening of the jet nozzle and the image of the laser imaged by the imaging means, and the focal point of the laser is moved to the center of the inlet opening of the jet nozzle. Alignment control means,
The alignment control means includes
a) determining a center of the inlet opening based on an image of the inlet opening of the jet nozzle;
b) determining the center of the laser image based on the image of the laser image irradiated near the inlet opening of the jet nozzle;
c) driving the relative movement mechanism to relatively move the jet nozzle and the focal point of the laser so that the center of the laser image coincides with the center of the entrance opening;
Is configured to run,
An alignment adjustment device characterized by that. The step a) stores in advance an image of the inlet opening including information on the center of the inlet opening of the jet nozzle and compares it with an image of the inlet opening of the jet nozzle imaged by the imaging means. By determining the center of the inlet opening,
The alignment adjusting apparatus according to claim 1. The step b) classifies the image of the laser image into a region having a predetermined luminance or higher and a region having a predetermined luminance or lower, and obtains the center of gravity of the region having the predetermined luminance or higher to obtain the center of the laser image. Having the step of:
The alignment adjustment apparatus according to claim 1 or 2. A power meter for measuring the output of the laser;
The alignment control means includes
d) Measure the output of the laser guided into the liquid column over a predetermined area with the power meter, and set the relative position of the jet nozzle and the focal point of the laser at a position where the measured laser output is maximized. Configured to perform further steps;
The alignment adjustment apparatus of any one of Claim 1 to 3. The laser optical system includes an optical fiber that guides the laser emitted from the laser light source, a collimating lens that collimates the laser from the optical fiber, and a condensing lens that condenses the laser from the collimating lens,
The relative movement mechanism is configured to move the focal point of the laser with respect to the jet nozzle by moving the optical fiber,
Further, the laser optical system is configured such that the moving distance of the optical fiber is larger than the moving distance of the focal point of the laser.
The alignment adjustment apparatus of any one of Claim 1 to 4. The imaging means includes a CCD camera, illumination that illuminates the vicinity of the jet nozzle, a filter disposed in a central portion of light from the illumination, a collimator lens that guides light from the illumination to the vicinity of the jet nozzle, and a condensing lens A lens, and a monitor that displays an image obtained by the CCD camera.
The alignment adjustment apparatus according to any one of claims 1 to 5. A jet nozzle that ejects liquid to form a liquid column, a laser light source that emits a laser, and a laser optical system that condenses the laser from the laser light source in the liquid column, are guided into the liquid column. An alignment adjustment method for aligning the focal point of the laser, which is used in a laser processing apparatus that processes a workpiece with a laser beam,
A) obtaining an image of the inlet opening of the jet nozzle and determining the center of the inlet opening based on the image of the inlet opening;
B) irradiating a weak laser near the entrance opening of the jet nozzle to obtain an image of the laser image, and determining the center of the laser image based on the image of the laser image;
And (c) relatively moving the jet nozzle and the focal point of the laser so that the center of the laser image coincides with the center of the entrance opening. The step A) stores in advance an image of the inlet opening including information on the center of the inlet opening of the jet nozzle, and compares the image with the captured image of the inlet opening of the jet nozzle. Determining the center of the opening,
The alignment adjustment method according to claim 7. The step B) classifies the image of the laser image into a region having a predetermined luminance or higher and a region having a predetermined luminance or lower, and obtains the center of gravity of the region having the predetermined luminance or higher to obtain the center of the laser image. Having the step of:
The alignment adjustment method according to claim 7 or 8. D) measuring the output of the laser guided into the liquid column over a predetermined region, and further setting the relative position of the inlet opening and the focal point of the laser at a position where the measured laser output is maximized Have
The alignment adjustment method according to any one of claims 7 to 9. The laser passing through the laser optical system is guided from the laser light source by an optical fiber, collimated by a collimating lens, and then condensed by a condenser lens.
The step C) moves the optical fiber to move the focal point of the laser with respect to the jet nozzle, and the moving distance of the optical fiber is larger than the moving distance of the focal point of the laser. Configured to,
The alignment adjustment method according to claim 7. In the steps A) and B), an image of the inlet opening or an image of the laser is obtained by illuminating the vicinity of the jet nozzle with illumination in which the central part of the light is covered by a filter,
The alignment adjustment method according to any one of claims 7 to 11. A laser processing apparatus for processing a workpiece by a laser guided by a liquid jet,
A jet nozzle that ejects liquid to form a liquid column;
A laser optical system for condensing the laser in the liquid column;
An alignment adjustment device according to any one of claims 1 to 6, comprising:
Laser processing equipment characterized by that.