JP2002120079A - Device and method for laser beam machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a laser beam machining with high precision by relatively positioning the irradiated position with a laser beam and the set position of a work. SOLUTION: The laser beam machining device 1 is so composed that the work is irradiated with the laser beam and the device is provided with an image pickup means 2 which irradiates the work with the laser beam and reads the image of an irradiated trace of the laser beam and the image of the set position of the work on the same axis with the laser beam axis, a deviation recognizing means 5 which stores the coordinate values of the laser beam machining position specified by the image of the irradiated trace of the laser beam and recognizes a relative deviation by comparing the coordinate values of the laser beam machining position with the coordinate values of the machining position of the work specified by the image of the set position of the work, and an irradiated position correction means 3 which moves the irradiated position with the laser beam according to the relative deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and a laser processing method for processing a workpiece by irradiating a laser beam.

[0002]

2. Description of the Related Art In recent years, processing techniques using laser light have been applied to various fields. For example, even in a process of manufacturing an electron gun for a cathode ray tube, a tungsten disk (hereinafter abbreviated as “WD”), which is a cathode component of the electron gun, is used.
Is irradiated with a laser beam to form a nugget. More specifically, the WD 11 made of a substantially disk-shaped sintered body as shown in FIG. 4A is irradiated with a laser beam to melt the surface layer portion, and the WD 11 is melted as shown in FIG. For example, a bulge (nugget) 12 formed when the metal hardens is produced.

[0003]

The processing accuracy in such laser processing is greatly affected by the positioning accuracy of the workpiece with respect to the irradiation position of the laser beam. For example, when the nugget 12 is formed on the WD 11, the formation accuracy of the nugget 12 is greatly affected by the relative positioning accuracy between the irradiation position of the laser beam and the setting position of the WD 11.

[0004] However, it is very difficult to suppress variations in the positioning accuracy of the set position of the WD 11 as a workpiece. This is because many WD1
If an attempt is made to efficiently form a nugget with respect to 1, for example, it is necessary to repeatedly move and position a plurality of WDs 11 using an index table, so that the positioning accuracy will vary by about several tens of μm. is there. Therefore, if such variation occurs, there is a possibility that the accuracy of the laser processing will be hindered.

[0005] Therefore, the present invention enables the relative positioning between the irradiation position of the laser beam and the set position of the workpiece even when the workpiece is set at an arbitrary position. Accordingly, an object of the present invention is to provide a laser processing apparatus and a laser processing method capable of performing high-precision laser processing.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a laser processing apparatus devised to achieve the above object, which irradiates a workpiece with laser light to process the workpiece. The laser irradiation means is disposed coaxially with the optical axis of the laser light irradiated by the laser irradiation means, and displays an image of a trace of irradiation of the laser light by the laser irradiation means and an image of a set position of a workpiece to be processed by the laser irradiation means. Image capturing means to be read; laser position storing means for storing coordinate values of a laser processing position specified from an image of a laser beam irradiation mark read by the image capturing means; The coordinate value of the processing position of the work specified from the image of the set position of the work is compared with the coordinate value of the laser processing position stored in the laser position storage means, and the deviation amount is recognized. A displacement amount recognizing means for, and is characterized in further comprising an irradiation position correcting means for moving the irradiation position of the laser light by the laser irradiation means in accordance with the shift amount where the displacement amount recognizing means has recognized.

Further, the present invention is a laser processing method devised to achieve the above object, wherein the method is used for processing a workpiece by irradiating the workpiece with laser light, The image of the irradiation mark obtained by the irradiation of the laser light is read coaxially with the optical axis of the laser light, and the coordinate value of the laser processing position specified from the image of the irradiation mark is stored, and the processing is performed by the laser light. The image of the set position of the workpiece to be read is read coaxially with the optical axis of the laser light, and the coordinate value of the processed position of the workpiece specified from the image of the set position and the laser which has already been stored. After recognizing the amount of deviation between the coordinates of the processing position and moving the irradiation position of the laser beam according to the recognized amount of deviation, the workpiece is irradiated with laser light to process the workpiece. It is characterized by the following.

[0008] According to the laser processing apparatus and the laser processing method having the above-described configuration, an image of an irradiation mark obtained by irradiating a laser beam is read prior to processing of a workpiece by irradiating the laser beam. The coordinate value of the laser processing position specified from the image is stored. Thereafter, when the workpiece is set, the image at the set position is read. At this time, since the image of the irradiation mark and the image of the workpiece are both read coaxially with the optical axis of the laser light, the degree of coincidence with the optical axis of the laser light is guaranteed. And
When the image at the set position is read, the deviation between the coordinate value of the processing position of the workpiece specified from the image and the coordinate value of the laser processing position already stored is recognized, and the deviation amount is recognized. The irradiation position of the laser beam is moved in accordance with. Thus, the irradiation position of the laser beam is corrected so as to match the processing position of the workpiece. That is, no matter where the set position of the workpiece is, the relative position between the laser processing position and the processed position of the workpiece is adjusted, and then the laser beam is irradiated to the processed position. Become. In addition, since the coordinate values specified from the laser light irradiation marks are stored and the relative position is adjusted based on the stored coordinate values, even if the irradiated laser light is an invisible laser light, it can be used. Is possible.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser processing apparatus and a laser processing method according to the present invention will be described below with reference to the drawings. However, here, a case will be described as an example in which laser processing is performed on a WD, which is a cathode component constituting an electron gun of a cathode ray tube.

First, a schematic configuration of a laser processing apparatus according to the present invention will be described. FIG. 1 is a schematic configuration diagram illustrating an example of a laser processing device according to the present invention, and FIG. 2 is an explanatory diagram illustrating a schematic configuration of a main part of the laser processing device.

As shown in FIG. 1, a laser processing apparatus 1 described in this embodiment is roughly divided into a laser processing unit 2 and
A position correction unit 3, a WD set unit 4, an image processing unit 5,
It is composed of

The laser processing unit 2 includes a laser oscillator 21 and a CCD (Charge Coupled), as shown in FIG.
Device section 22 and a laser emission lens section 23.

The laser oscillator 21 emits laser light necessary for laser processing of the WD 11. However, in the laser oscillator 21, for example, YAG (Yttrium Aluminum)
Garnet) emits invisible laser light such as a laser.

The CCD section 22 reads an image by photoelectric conversion. However, the CCD section 22 reads an image of a laser beam irradiation mark by the laser oscillator 21 and an image of a set position of the WD 11 to be processed by the laser oscillator 21.

The laser emitting lens portion 23 has a laser oscillator 21 mounted on its side and a CCD portion 22 mounted thereon, and is provided with a mirror (prism) 24 for reflecting and refracting only laser light. The optical path of the laser light emitted in a substantially horizontal direction from the laser
The laser beam is bent by 0 °, and the laser beam bent in a substantially vertical direction is imaged on the surface of the WD 11 which is a workpiece by the emission lens 25 disposed below. Further, the visible light incident from the exit lens 25 is transmitted through the mirror 24 without changing the optical path, and is passed through the eyepiece 26 attached above to the CCD unit 22.
Is made to enter. That is, the laser emission lens unit 23 shares the emission lens 25,
By providing the mirror 24 that reflects and refracts only the laser light, the optical axis of the laser light from the laser
The optical axis of the visible light to the CCD unit 22 is the same on the laser light emission side.

In FIG. 1, the position correction unit 3 includes an XY stage 31 and a Z stage 32 that support the laser processing unit 2, and is used to move the support position of the laser processing unit 2. However, the position correction unit 3 drives each of the servo motors for operating the XY stage 31 and the Z stage 32 while following the control instructions from the image processing unit 5, so that the laser processing unit 2
Is moved in the X, Y, and Z directions.

The WD setting section 4 has a disk-shaped index table 41 formed so that a plurality of WDs can be set. The index table 41 is rotated intermittently by a predetermined angle, thereby obtaining the index table 41. The WD 11 set above is transported and positioned. The supply and removal of the WD 11 from the index table 41 are performed by a handling robot (not shown).

The image processing unit 5 includes a CPU (Central Processing Unit) for executing a predetermined program and an E ² PROM.
(Electrically Erasable Programmable Read Only Mem
ory) and a combination of storage devices and the like, as will be described in detail later, based on operation control required when performing laser processing on the WD, for example, based on an image reading result by the CCD unit 22 of the laser processing unit 2. An operation control is performed such that a servo motor operation instruction is given to the position correction unit 3 to move the support position of the laser processing unit 2.

Next, an example of a processing operation in the laser processing apparatus 1 configured as above, that is, a procedure of a laser processing method according to the present invention will be described. FIG. 3 is a flowchart showing an example of the procedure of the laser processing method according to the present invention.

As shown in FIG. 3, in the laser processing apparatus 1, prior to performing the laser processing on the WD, a pre-stage process for grasping the laser processing position by the laser processing unit 2 is performed.

In the pre-stage processing, first, the sample W set on the index table 41 of the WD setting unit 4 is set.
When D or a special jig equivalent thereto (hereinafter, these are simply referred to as “samples”) are conveyed and positioned below the laser processing unit 2, the laser oscillator 21 of the laser processing unit 2 emits, for example, a YAG laser beam. Then, laser irradiation is performed on the sample via the mirror 24 and the emission lens 25 of the laser emission lens unit 23 (Step 101, hereinafter, step is abbreviated as “S”). Then, when laser irradiation is performed on the sample, C
The CD section 22 is the emission lens 2 of the laser emission lens section 23.
5. The image of the irradiation mark of the laser light applied to the sample is read via the mirror 24 and the eyepiece 26 (S102). At this time, it is desirable to illuminate the sample irradiated with the laser light with external illumination or the like in order to sharpen the image of the irradiation mark.

When the CCD unit 22 reads the image of the laser beam irradiation mark, the image processing unit 5 receives image data as a result of reading the image from the CCD unit 22 and coordinates the image data with the coordinates. Image processing for conversion is performed, and the coordinate position of the laser beam irradiation mark on the reading screen of the CCD unit 22 is recognized (S103). That is, the image processing unit 5 recognizes the coordinate value of the actual laser irradiation position (hereinafter, referred to as “laser processing position”) specified from the image of the laser beam irradiation mark based on the image data received from the CCD unit 22. I do. Then, the image processing unit 5
The coordinate value of the recognized laser processing position is stored and held in a storage device such as an E ² PROM (S104). Note that the image processing itself for coordinate conversion and coordinate value recognition in the image processing unit 5 uses a well-known technique, and thus description thereof is omitted here.

The laser processing apparatus 1 performs the processing up to this point
This is performed as a pre-process of laser processing for WD.

When the pre-process is completed, the laser processing apparatus 1 starts laser processing on the WD. W
In the laser processing of D, first, the workpiece W
D11 is set on the index table 41 of the WD setting unit 4, is conveyed to a position below the laser processing unit 2, and is positioned (S105). At this time, since the position correction unit 3 moves the support position of the laser processing unit 2 as described later, the WD setting unit 4 does not need high-precision positioning. Therefore, it is naturally expected that the set position of the WD 11 below the laser processing unit 2 will have some variation.

Therefore, in the laser processing unit 2, when the WD 11, which is a workpiece, is set below the laser processing unit 2, the CCD unit 22 is driven through the emission lens 25 of the laser emission lens unit 23, the mirror 24 and the eyepiece 26. , The relevant WD11
The image at the set position is read (S106). Also at this time, it is desirable to illuminate the WD 11 on the index table 41 with external lighting or the like in order to sharpen the image at the set position.

When the CCD unit 22 reads an image at the set position of the WD 11, the image processing unit 5 receives image data as a result of reading the image from the CCD unit 22,
The image data is subjected to image processing for coordinate conversion, and the coordinates of the set position of the WD 11 on the reading screen of the CCD unit 22 are recognized (S107). More specifically, using a set value of an ideal nugget formation position and a well-known pattern recognition technique, based on image data received from the CCD unit 22, a laser beam is specified to the WD 11 specified from the set position of the WD 11. Recognize the coordinate value of the position to be irradiated (hereinafter, referred to as “processed position”).

Then, the image processing section 5 recognizes the WD1
Then, the coordinate value of the first processing position is compared with the coordinate value of the laser processing position already stored and held in the previous process, and it is recognized whether or not there is a deviation in the relative relationship between the respective coordinate values (S10).
8). As a result of this recognition, if there is a shift amount,
The image processing unit 5 gives an instruction to operate the servo motor to the position correction unit 3 so as to eliminate the deviation amount.

Upon receiving an operation instruction from the image processing unit 5, the position correction unit 3 drives the servo motor 33 of the XY stage 31 and, if necessary, the servo motor of the Z stage 32 while following the operation instruction. Then, the support position of the laser processing unit 2 is moved (S109). By this movement,
The amount of deviation between the processing position and the laser processing position is corrected. In other words, even if the WD setting unit 4 does not perform high-precision positioning and there is some variation in the setting position of the WD 11, the variation is corrected by moving the support position of the laser processing unit 2.

After that, in the laser processing section 2, the laser oscillator 21 emits, for example, a YAG laser beam, and passes through the mirror 24 and the emission lens 25 of the laser emission lens section 23 on the index table 41 of the WD set section 4. W
Laser irradiation is performed on D11 (S110). Thereby, the W irradiated with the laser light from the laser oscillator 21
The nugget 12 is formed at the ideal nugget formation position on the WD 11 at D11.

After the nugget 12 is formed on the WD 11, it is preferable that the image processing unit 5 verify the nugget formation position in order to further improve the nugget 12 formation position accuracy (S111). In particular,
When the nugget 12 is formed on the WD 11, the image of the WD 11 after the nugget is formed is read by the CCD unit 22 through the emission lens 25 of the laser emission lens unit 23, the mirror 24, and the eyepiece 26. Also at this time, in order to sharpen the read image, WD1 after forming the nugget is formed.
It is desirable to illuminate 1 with external lighting or the like. Then, the image processing unit 5 receives image data as a result of reading the image from the CCD unit 22, measures the position of the formed nugget 12 with respect to the outer shape of the WD 11 based on the image data, and measures the position from the center of the WD 11. , The nugget diameter and the like are recognized, and it is determined whether or not the recognition result is within a preset allowable value.

As a result of this verification, if the recognition result such as the amount of deviation or the diameter of the nugget is not within the allowable range, the WD 11 to be verified has a nugget 12 due to some factor.
The image processing unit 5 determines that a defect has occurred in the formation position of
Outputs a signal (flag or the like) or an alarm to that effect, and notifies the host computer or the operator of the laser processing apparatus 1 which is a host apparatus of the laser processing apparatus 1 of that.

After the laser processing for one WD 11 is completed in this way, when the laser processing for the next WD is performed (S112), the operation processing other than the above-described pre-step processing is repeated again (S105). ~ S11
1). If there is no next WD set on the index table 41 of the WD set unit 4, the laser processing apparatus 1 ends the laser processing on the WD.

As described above, according to the laser processing apparatus 1 described in the present embodiment and the laser processing method executed by the laser processing apparatus 1, the laser processing is performed in accordance with the amount of deviation recognized by the image processing unit 5. After moving the support position of the portion 2, that is, the irradiation position of the laser beam, the WD which is the workpiece
The WD 11 is processed by irradiating a laser beam to the WD 11. Therefore, even if the WD setting unit 4 does not perform positioning with higher precision than necessary, the WD 11
The nugget formation position does not vary. In other words, laser processing of the workpiece WD11 can be performed with high accuracy and efficiency.

In the laser processing apparatus 1 and the laser processing method according to the present embodiment, the image of the laser beam irradiation mark is read in the pre-stage processing, and the coordinates of the actual laser processing position are recognized and stored. , This and the workpiece WD1
By comparing the result of reading the image at the first set position with the read result, the irradiation position of the laser beam when the WD 11 is irradiated with the laser beam is moved. Therefore, since the actual laser processing position is used as the basis, it is possible to reliably realize high-precision laser processing for the WD 11. In addition, since the laser processing position is acquired and stored in the pre-stage processing, it is not necessary to acquire the laser processing position every time the laser beam is irradiated, and this also improves the efficiency of laser processing for the WD11. Can be achieved.

For obtaining the actual laser processing position, it is conceivable to use a laser pointer (visible laser light) using, for example, a He-Ne laser. However, in this case, there is a possibility that a shift in the focal position between the invisible laser light used for laser processing and the visible laser light used for acquiring the laser processing position may cause a problem. In this regard,
In the laser processing apparatus 1 and the laser processing method of the present embodiment, since the laser processing position is obtained from the irradiation mark of the laser light when the invisible laser light is irradiated in the pre-stage processing,
A shift in the focal position does not cause a problem, and it is possible to ensure sufficient positional accuracy and to cope with a non-visible laser beam irradiated at the time of laser processing.

Further, in the laser processing apparatus 1 and the laser processing method of the present embodiment, acquisition of the laser processing position and W
The image reading by the CCD unit 22 required for recognizing the set position of D11 is performed coaxially with the optical axis of the laser light emitted from the laser oscillator 21. Therefore, the relative relationship between the optical axis of the visible light to the CCD unit 22 and the optical axis of the laser light to the WD 11 is guaranteed, and an error occurs between the recognition result of the laser processing position and the actual laser processing position. Can be avoided. In addition, since the laser processing is performed coaxially, it is not necessary to retract the laser processing unit 2 every time the CCD unit 22 reads an image. From these points, the laser processing apparatus 1 of the present embodiment is also considered.
It can be said that the laser processing method for the WD 11 can reliably increase the accuracy of the laser processing method.

The coaxialization of the laser light from the laser oscillator 21 and the visible light to the CCD unit 22 is performed by the laser processing device 1.
This also simplifies the configuration of the device, so that the size of the device and the system including the device can be easily reduced.

Further, as in the laser processing apparatus 1 and the laser processing method of the present embodiment, the nugget 1
If the image processing unit 5 verifies the nugget formation position using the result of the image reading by the CCD unit 22 after the formation of the WD 2, the variation of the set position of the WD 11 is determined by the laser processing unit 2. The result of correction by moving the support position is confirmed, and the WD 11 in which the nugget formation position is not within the allowable value can be excluded, so that the laser processing can be further performed with higher accuracy.

In this embodiment, a YAG laser is used as an example of the invisible laser beam used for laser processing.
The present invention is not limited to this, and can be similarly applied to other laser beams (for example, a CO ₂ laser). However, when a YAG laser is used, since a fiber can be used in the optical path, the size and space of the laser processing unit 2 can be easily reduced, and the movement and positioning of the laser processing unit 2 can be performed quickly and accurately. It is possible to do.

Further, in the present embodiment, a case has been described as an example in which laser processing is performed on the WD, which is a component of the cathode constituting the electron gun of the cathode ray tube, but the present invention is not limited to this. Instead, it is conceivable to apply the same method to other workpieces.

[0041]

As described above, in the laser processing apparatus and the laser processing method according to the present invention, the coordinate value of the laser processing position specified from the image of the irradiation mark of the laser light is stored, and the laser light is used. The set position of the workpiece is read coaxially with the optical axis of the workpiece, and the deviation between the coordinate value of the workpiece position of the workpiece and the coordinate value of the laser processing position already stored is recognized. After the irradiation position of the laser beam is moved according to the deviation amount, the workpiece is irradiated with the laser beam to process the workpiece. Therefore, even if the workpiece is not positioned at the set position with higher accuracy than necessary, there is no variation in the position of the laser processing on the workpiece. That is, according to the laser processing apparatus and the laser processing method of the present invention, laser processing on a workpiece can be performed with high accuracy and efficiency.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a main part of an example of a laser processing apparatus according to the present invention.

FIG. 3 is a flowchart illustrating an example of a procedure of a laser processing method according to the present invention.

FIGS. 4A and 4B are diagrams showing a tungsten disk as an example of a workpiece to be laser-processed; FIG. 4A is a perspective view showing the appearance of the tungsten disk; FIG. It is explanatory drawing which shows the tungsten disk after.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus, 2 ... Laser processing part, 3 ... Position correction part, 4 ... WD setting part, 5 ... Image processing part, 11 ... WD
(Tungsten disk), 12: nugget, 21: laser oscillator, 22: CCD unit, 23: laser emitting lens unit

Claims (4)

[Claims] A laser irradiation means for irradiating the workpiece with laser light to process the workpiece; and a laser irradiating means disposed coaxially with an optical axis of the laser light emitted by the laser irradiating means. An image capturing means for reading an image of a laser light irradiation mark by the means and an image of a set position of a workpiece to be processed by the laser applying means; and an image of the laser light irradiation mark read by the image capturing means. Laser position storage means for storing the coordinate value of the laser processing position, and the coordinate value of the processing position of the workpiece specified from the image of the set position of the workpiece read by the image capturing means, A shift amount recognizing unit that compares the coordinate value of the laser processing position stored in the laser position storage unit with the amount of the shift and recognizes the shift amount; Laser processing apparatus characterized by comprising an irradiation position correcting means for moving the irradiation position of the laser beam by The irradiating means. 2. A processing position verification that verifies a processing position specified from the image when the image capturing unit reads an image of the workpiece after processing by irradiating the laser beam with the laser irradiation unit. 2. A laser processing apparatus according to claim 1, further comprising means. 3. The laser processing apparatus according to claim 1, wherein the workpiece is a tungsten disk serving as a part of a cathode constituting an electron gun of a cathode ray tube. 4. A laser processing method used when processing a workpiece by irradiating the workpiece with laser light, wherein an image of an irradiation mark obtained by the laser light irradiation is converted to a light of the laser light. It is read coaxially with the axis and stores the coordinate value of the laser processing position specified from the image of the irradiation mark, and the image of the set position of the workpiece to be processed by the laser light is stored in the optical axis of the laser light. And coaxially read to recognize the amount of deviation between the coordinate value of the processing position of the workpiece specified from the image of the set position and the coordinate value of the laser processing position already stored. A laser processing method characterized by irradiating a laser beam onto a workpiece after moving an irradiation position of the laser beam in accordance with a shift amount, and processing the workpiece.