JPH09141458A - Laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent machining accuracy with simple teaching operation. SOLUTION: In the teaching work, a control part 23 automatically perform the accurate positioning to the machining line only by moving an outgoing optical system 10 or a work table 65 so that the machining line enters in the view by a CCD camera 13, and the movement to the next teaching point is performed only by pressing a button of a teaching box 25. In addition, when a plurality of machining lines are detected at one time in detecting the machining lines in an image processing part, an operator watches the machining line on the superposed images displayed on a monitor 69-2 and can select the most favorable machining line by a selection part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for welding or cutting a work by displacing an output optical system for laser beam irradiation or the work.

[0002]

2. Description of the Related Art An example of this type of laser processing apparatus will be schematically described with reference to FIG. In FIG. 8, a work table 65 on which a work (not shown) is mounted can be moved in one direction (here, referred to as an x-axis direction) by a first ball screw mechanism 61. Further, the first ball screw mechanism 61 is mounted on the second ball screw mechanism 62 so as to be movable in the y-axis direction. Further, an arm 64 is attached to the third ball screw mechanism 63 so as to be movable in the z-axis direction. The arm 64 is driven by a laser beam irradiation optical system for irradiating the laser beam in the x-, y-, and z-axis directions. A laser irradiation unit 100 including a driving unit is attached.

A drive unit 6 incorporating a laser oscillation source and the like
A cable-shaped optical fiber 67 is led out from the optical fiber 6, and the optical fiber 67 is connected to the arm 64 and the laser irradiation unit 1.
Laser irradiation unit 1 in a state where it can be deformed in conjunction with the movement of 00
00 is connected. As the laser oscillation source, for example, a YAG laser device is used.

In this type of laser processing apparatus, a teaching box 68 is used for teaching or teaching support. The teaching box 68 is provided with a switch for switching between teaching and actual laser processing, a switch for starting and stopping the apparatus, a button for remote operation, and the like. The displacement of the mechanism and the output optical system can be operated. The teaching box 68 is attached to the main control section 69 or can be remotely operated by wire. The main control unit 69 includes an operation panel 69-1 for inputting various setting values and the like, and a monitor 69-2 for displaying various data.

When laser processing, for example, welding is performed, teaching is performed in advance using a teaching box for each work. That is, the operator operates the teaching box 68 for teaching before starting welding by automatic control.

Referring to FIGS. 9 to 12, the teaching when a CCD camera is mounted on the emission optical system will be described. When the operator selects the switch of the teaching box 68 to the teaching mode, a teaching beam is emitted from the emission optical system 70 as shown in FIG. The operator refers to this teaching beam and the work table 65 so that the work line L1 to be welded on the work 71 may enter within the field of view of the CCD camera displayed on the monitor 69-2.
(FIG. 8) is moved (first step). Since the teaching beam only needs to have a guiding function, a beam different from the laser beam, for example, a He-Ne beam is usually used. When the first step is completed, the teaching beam is temporarily stopped.

Next, as shown in FIG. 10, the operator sets a center point (reference point) set on the image of the CCD camera.
The position of the worktable 65 is finely adjusted so that C1 is located on the line to be processed L1. In FIG. 10, the line to be processed L <b> 1 is enlarged and represented by hatching with a small interval. The center point C1 is set in advance to be the optical axis position of the laser beam in actual welding. Then, while maintaining this state, the work table 65 is moved to move the center point C1 to the next teaching point in the extending direction of the line L1 to be processed (second step).

FIG. 11 shows a step (third step) of making the focal point of the processing laser beam to be irradiated coincide with the processing point on the line L1 to be processed, and FIG.
Shows the step (fourth step) of making the optical axis of the processing laser beam to be irradiated when the processing surface is curved, perpendicular to the workpiece 71 (automatic focusing). Automation is realized by a function called an automatic attitude control function. In any case, the operator executes the above-described first to fourth steps for each teaching point, for example, every 100 mm, designates inputting of teaching data each time, and stores the teaching data in the storage device.

That is, the operator uses the position data of the emission optical system 70 and the work table 65 from the start point to the end point of the processing line L1 obtained as described above as teaching data for each of the teaching points as the main control unit 69. Is stored in a storage device incorporated therein. In actual welding, the main controller 69
Reads the teaching data from the storage device and automatically controls the movement of the emission optical system 70 or the work table 65 using the read teaching data.

[0010]

However, CCDs
Since the operator moves the work table 65 even when looking at the enlarged display screen captured by the camera, the work table 65 is moved so that the center point C1 of the image coincides with the work line L1 to be welded for each teaching point. Difficult to move.
In addition, apart from the case where the line to be processed L1 is a single straight line,
Since a plurality of teaching points are required, the time for teaching also becomes longer. This is a serious problem particularly in high-precision processing using a YAG laser.

[0011] In view of the above problems, an object of the present invention is to provide a laser processing apparatus capable of obtaining high processing accuracy with a simple teaching operation.

[0012]

According to the present invention, there is provided a work table provided with the above-mentioned output optical system and the work so that the optical axis of a laser beam emitted from the output optical system moves on a line to be processed of the work. In a laser processing apparatus for performing laser processing by moving at least one of the laser processing apparatus, a CCD camera provided in the emission optical system for capturing an image of a predetermined range including the line to be processed of the work; A teaching box capable of remotely controlling the movement of the system and the work table by an operator, a control unit for controlling movement of the emission optical system and the work table based on the operation of the teaching box, and A predetermined process is performed on an image including the line to be processed to reduce the number of lines approximating the line to be processed. Also, an image processing unit for detecting one processing line, a drawing unit for creating the processing line detected by the image processing unit as an approximate processing line for displaying on a monitor, and a drawing unit created by the drawing unit. The teaching box includes an image superimposing unit for superimposing an approximate processed line and an image from the CCD camera and displaying the processed line and the approximate processed line on the monitor. When there are a plurality of processing lines detected at one time by the image processing unit, the selection means selected to select one of the plurality of approximate processing lines displayed on the monitor in an overlapping manner. The operator has a designating means for designating a moving direction on the approximate machining line. In the teaching operation, the operator moves the work table by operating the teaching box to move the CCD cover. In the teaching operation, the control unit controls the reference point to be set in advance in the image of the CCD camera to be the optical axis of the laser beam, and Calculate a positional deviation from the nearest point to the reference point on the selected approximate processing line, and move the work table so that the reference point matches the nearest point based on the calculated positional deviation. It has an automatic positioning function for controlling, and after the automatic positioning, the movement of the work table is controlled so as to move the reference point in the line direction designated by the designation means.

[0013]

According to the present invention, the teaching operation can be performed only by moving the emission optical system or the work table so that the line to be processed is within the field of view of the CCD camera, and reference to the line to be processed can be performed. Precise positioning of points is automatically performed, and movement to the next teaching point is performed only by pressing a button. In addition, when a plurality of processing lines are detected at once by the image processing unit, the operator looks at the approximate processing line on the superimposed image displayed on the monitor and selects the most preferable approximate processing line by the selection unit. be able to.

[0014]

FIG. 2 shows a schematic configuration of an exit optical system 10 used in the present invention, and may be used in place of the exit optical system described in FIG. A laser beam B1 from a laser oscillation source passes through an optical fiber and emits an optical system 1.
The light is introduced into the workpiece 20 through the processing lens 12 at an angle changed by the mirror 11. When teaching using a teaching box, a He-Ne beam B2 is supplied through an optical fiber as described later,
The work 20 is irradiated. C on the upper part of the exit optical system 10
A CD camera 13 is provided, and the CCD camera 13 captures an image of a predetermined range including a line to be welded through the observation lens 14.

The optical axis of the CCD camera 13 and the laser beam B
The optical axis of 1 is set in advance to match,
Moreover, the CCD camera 13 is placed at the focus position of the laser beam B1.
Has been adjusted to focus. In other words,
When the optical axis and the focus of the CCD camera 13 are aligned with the line to be processed on the work 20, the optical axis and the focal point of the laser beam B1 are made to coincide with them. This is also the case for the He-Ne beam used for teaching.

The image resolution of the CCD camera 13 is 256 × 256 pixels, and one pixel is about 0.02 (m).
m). Also, the field of view of the CCD camera 13 is 5 × 5.
(Mm). This takes into account that when the field of view is narrowed, the imaged area is enlarged and the detection accuracy is improved, but when the field is too narrow, the work of the operator involved in teaching becomes fine and the amount of work increases. The present invention reduces this amount of work. The image is represented by 256 gradation colors (luminance) according to the light intensity.

FIG. 1 shows a configuration necessary for performing teaching or teaching support using a teaching box in a laser processing apparatus according to the present invention. The image from the CCD camera 13 is sent to the image processing unit 21 and sent to the monitor 69-2 through the image superimposing unit 22 for display. The image processing unit 21 detects at least one processing line that approximates a line to be processed on the work 20 by performing predetermined image processing described later. The detected processing line is sent to the control unit 23 and the drawing unit 24.

The teaching box 25 is used by an operator to perform a teaching operation to be described later. In the case of a configuration as shown in FIG. Or the movement and posture of the emission optical system 10 in the z-axis direction can be changed.

The control unit 23 has an automatic positioning function described below. The control unit 23 determines the focal point of the laser beam, that is, the center point of the image set in the CCD camera 13 (the center point C1, FIG. The shift from the close point is calculated, and the movement amount of the reference point required to make the reference point coincide with the closest point on the detected processing line is calculated. In this case, the amount of movement of the work table 65 is calculated.

Specifically, at the start of the automatic alignment, the control unit 23 sends the position of the reference point from the operation panel 69-1 and the plurality of position sensors 26, the coordinate system of the field of view of the CCD camera 13, the processing axis, Data indicating the positional relationship in the machine coordinate system of the work table 65 is fetched. Then, the position of the detected processing line and the position of the reference point on the image of the monitor 69-2 are determined. The control unit 23 calculates a moving amount for moving the reference point to the nearest point on the detected processing line. The control unit 23 controls the movement of the work table 65 based on the calculation result to make the reference point coincide with the detected processing line.

According to such automatic positioning, the operator operates the teaching box 25 to operate the CCD camera 13 when the line to be processed on the work 20 is largely out of the field of view of the CCD camera 13 during the teaching operation. Work table 6 so that the line to be processed is included in the image of
It is only necessary to move the reference point 5 to move the reference point close to the line to be processed, and the operation of matching the reference point with the line to be processed is automatically performed.

The teaching box 25 used in the present invention has a liquid crystal monitor, an emission optical system 10, and an operation section for operating the displacement of the work table 65, and is connected to the main control section 69 by wire or wirelessly. The operator
When teaching, hold this teaching box 25,
It is only necessary to operate the operation unit while looking at the monitor 69-2 to move the work table 65 so that the line to be processed enters the image.

In the present invention, the emission optical system 10 is controlled through the robot arm drive system 27 by operating a button on the teaching box 25 to activate the automatic attitude control function and the automatic focusing function described above for each teaching. The optical axis of the laser beam B1 and the He-Ne beam B
The optical axis 2 is perpendicular to the surface of the work 20 and the focal point coincides with the point to be processed.

Referring to FIG. 3, the flow of the processing line detection operation will be described. In step S1, He-N as described above is used.
After rough positioning by e-beam, C
The area including the processing line L1 is photographed by the CD camera 13. In step S2, an analog image signal from the CCD camera 13 is converted into a digital signal and taken into the image processing unit 21. First, the image processing section 21 performs preprocessing on the digital signal in step S3. Here, as pre-processing, line emphasis and noise removal processing are performed utilizing the characteristics of the line to be processed. Next, the process proceeds to step S4 to perform a binarization process. This binarization process is a process in which a certain appropriate luminance is set as a threshold, pixels having higher luminance are set to white, and pixels having a luminance lower than the threshold are set to black to form a black-and-white image. The L1 portion is displayed in black.

In step S5, the image processing unit 21
A processing line is detected for the black portion after the value processing, and a processing line is determined in step S6. In order to perform such line detection, the present invention employs a line detection algorithm called “Hough transform processing”. Based on the detected processing line on the workpiece 20, the control unit 23 controls the CCD camera 13
Is calculated from the reference point. Then, based on the shift amount, the movement amount of the work table 65 for moving the reference point of the image of the CCD camera 13 to the nearest point on the detected processing line is calculated. The "Hough transform process" is disclosed in Japanese Patent Application No. 7-47628, and a detailed description thereof will be omitted.

FIG. 4 shows the processing line detected from the start point to the end point of the processing line L1 so as to overlap with the processing line L1 with a single straight line. The control unit 23 controls the work table driving system 28 for moving the work table 65 based on the movement amount for automatic alignment obtained each time teaching is performed, so that the reference point is located on the detected processing line. The work table 65 can be moved so as to match. After the automatic alignment, the operator sets the teaching box 2
By performing a designation operation of taking in position data from 5, the position data of the emission optical system 10 and the work table 65 are stored in the storage device. This teaching operation is usually performed every time the direction of the line to be processed L1 changes.

In other words, if the processing line L1 is a straight line, the teaching operation may be performed at two points, the start point and the end point.
If the direction changes at a certain angle, the teaching operation is performed at this change point. Further, even when the line to be processed L1 is meandering gently, it can be approximated by a straight line if it is divided at intervals of several mm. In this case, it is sufficient to teach at the point that the direction of the approximate straight line changes. . In any case,
When the operator teaches, the line to be processed L1 is CC.
The work table is moved so as to be within the image of the D camera 13, and the image processing starts, the automatic positioning starts,
It is only necessary to perform the operation of designating the import of the position data, and it is not necessary to perform an accurate operation of aligning the reference point with the line to be processed L1.

The position data of the work table 65 accompanying the teaching is determined by the detected processing line, and the position data is stored in the storage unit in the control unit 23. Then, in the subsequent actual laser welding, the control unit 23 moves the work table 65 based on the position data stored in the storage unit.

By the way, in the image processing section 21, 1
In some image processing, a plurality of processing lines may be detected. This is because the surface of the work 20 has not only the line to be processed L1 but also scratches and dirt. In the present invention, taking such points into consideration, an image superimposing unit 22 and a drawing unit 24 are provided as shown in FIG. 1, and a selector (not shown) for the detected processing line is provided in the teaching box 25. The operation is described below. When the image processing unit 21 detects a plurality of processing lines in one image processing, it sends them to the drawing unit 24. The drawing unit 24 creates approximate processed lines for displaying these processed lines on the monitor 69-2 from the information indicating these processed lines and sends them to the image superposition unit 22. In the image superimposing unit 22, the image of the work 20 including the processing line L 1 from the CCD camera 13 is added to the drawing unit 24.
A superimposing process for displaying a plurality of approximate processed lines from the above is overlapped and displayed. The superimposed image created by the image superimposing unit 22 in this way is displayed on the monitor 69-2. The selection by the selector is performed by the monitor 6
In order to select the most preferable processing line from the plurality of processing lines displayed in 9-2, the selection is performed by moving the cursor with a button on the teaching box 25.

A description will be given also with reference to FIG. 5 showing a display example. Here, as shown in FIG. 5, it is assumed that an image captured by the CCD camera 13 includes a line L2 due to a scratch or dirt in addition to the line to be processed L1. Upon receiving such image information, the image processing unit 21 detects not only the approximate processing line L1 'that matches the processing line L1, but also the approximate line L2' that matches the line L2. Therefore, the drawing unit 24 creates an image for displaying not only the approximated processing line L1 'but also the approximated line L2' on the monitor, and the image superimposing unit 22 generates the image.
The images from the drawing unit 24 are superimposed and sent to the monitor 69-2. As a result, as shown in FIG. 5, the monitor 69-2 displays an image in which the approximate processed line L1 ′ and the approximate line L2 ′ are overlapped with the processed line L1 and the line L2 due to scratches, stains, etc., respectively. .

When the operator looks at such a display image, the operator determines that the relationship between the processing line L1 near the center and the approximate processing line L1 'is the most preferable, and determines the relation between the processing line L1 and the approximate processing line L1'. Teaching box 2
5 Select with the selector above. This selection operation is performed by moving the cursor with a push button for moving the cursor on the monitor 69-2 provided on the selector, and specifying it. The selection is confirmed by another push button.

As described above, the monitor display is performed by overlapping the line detected by the image processing section 21 with the line to be processed L1 photographed by the CCD camera 13 and other lines. The operator can quickly determine which of the detected lines is the processing line and can easily select it with the selector. Thereafter, the reference point is changed to the approximate processing line L1 'as shown in FIG.
Aligned to the closest point above.

By the way, when moving to the next teaching point,
Conventionally, the operator has moved along a processing line while performing operations on a plurality of processing axes, for example, x-axis and y-axis, on a work table while watching a monitor. On the other hand, in the present invention, the movement direction can be designated by operating a button on the teaching box 25 after the automatic positioning. That is, the operator can know the moving direction to the next teaching point by seeing the display image as shown in FIG. 6, and operates the button for designating the moving direction of the up, down, left and right on the teaching box 25. And specify the direction of movement. As a result, the control unit 23 sets the approximate processing line L1
The vector of the designated moving direction in 'is calculated, and the movement of the work table 65 is controlled so that the reference point moves in the direction of the calculated vector. As a result, the operator simply presses the button for designating the movement of the work table 65, and the control unit 23 performs the movement control in the vector direction calculated at the end of the automatic alignment,
As a result, the reference point moves on the approximate processing line L1 '. This moving direction is, as shown in FIG.
3 is displayed along with the x-axis on the image. This allows the operator to consider only the movement in the x-axis direction, which simplifies the movement work to the next teaching point and shortens the work time.

The above description is for the case of welding. In this case, straight lines can be detected by the presence of a welding line as a line to be processed. On the other hand, in the case of cutting, the cutting line is drawn as a line to be processed by scribing etc. in the part to be cut of the work, the cutting line is detected by the same processing, and automatic positioning and automatic positioning are completed. Later moves can be made.

[0035]

As described above, in the laser processing apparatus according to the present invention, when teaching, the operator only has to move the work table so that the line to be processed on the work falls within the field of view of the CCD camera. The processing section detects the processing line, and the control section moves the work table so as to match the processing line at which the reference point set in the image of the CCD camera is detected, so that the operation of the operator is easy,
Work volume and time are also significantly reduced. And 0.1m
m can be detected with an accuracy within 0.1 mm. Further, even if a plurality of processing lines are detected due to scratches or dirt on the work in the image processing apparatus, these are displayed on the monitor, and the operator can quickly determine the processing line by selecting one of them. In addition, the operator only needs to move the work table with respect to one axis for the movement after the end of the automatic positioning, and the amount of work for moving to the next teaching point is greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration necessary for a teaching operation in the present invention.

FIG. 2 is a sectional view schematically showing an internal structure of an emission optical system in the laser processing apparatus according to the present invention.

FIG. 3 is a flowchart for explaining an operation necessary for detecting a processing line in the present invention.

4 is a diagram showing an example in which a processing line detected by the operation described with reference to FIG. 3 is displayed so as to overlap a processing line.

FIG. 5 is a diagram showing an example of a monitor display for explaining a selection operation when a plurality of processing lines are detected in the image processing unit.

FIG. 6 is a diagram showing an example of a monitor display automatically aligned according to the present invention.

FIG. 7 is a diagram showing an example of a monitor display for explaining a moving direction after completion of automatic positioning according to the present invention.

FIG. 8 is a perspective view showing a schematic configuration of a laser processing apparatus to which the present invention is applied.

FIG. 9 is a diagram for explaining a rough alignment of an emission optical system according to a conventional teaching.

FIG. 10 is a diagram for explaining precise alignment of an emission optical system in the conventional teaching.

FIG. 11 is a diagram for explaining the focus position adjustment of the laser beam of the emission optical system in the conventional teaching.

FIG. 12 is a diagram for explaining optical axis alignment of a laser beam of an emission optical system in the conventional teaching.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Emission optical system 11 Mirror 12 Processing lens 13 CCD camera 14 Observation lens 61 First ball screw mechanism 62 Second ball screw mechanism 63 Third ball screw mechanism 64 Arm 65 Work table 66 Drive unit 67 Optical fiber 68 Teaching box 69-1 Operation panel 69-2 Monitor 100 Laser irradiation unit

Claims (1)

[Claims] 1. Laser processing by moving at least one of the emission optical system and a work table on which the work is mounted so that the optical axis of a laser beam emitted from the emission optical system moves on a line to be processed of the work. In the laser processing apparatus for performing, a CCD camera provided in the emission optical system for photographing an area of a predetermined range including the line to be processed of the work, and moving the emission optical system and the work table. A teaching box that can be remotely operated by an operator, a control unit for controlling movement of the emission optical system and the work table based on the operation of the teaching box, and an image including the line to be processed from the CCD camera. A predetermined processing is performed on the processing line to detect at least one processing line approximate to the processing line. An image processing unit for processing, a drawing unit for creating a processing line detected by the image processing unit as an approximate processing line for displaying on a monitor, and an approximate processing line created by the drawing unit and the CCD camera. An image superimposing unit for superimposing the image of the processing line and displaying the processed line and the approximate processing line on the monitor in a state where they are coincident with each other, wherein the teaching box is detected by the image processing unit at one time. When there are a plurality of processed lines, the selecting means for selecting any one of the plurality of approximate processed lines superimposed and displayed on the monitor and the moving direction on the selected approximate processed line are changed. The operator moves the work table by operating the teaching box to perform the teaching operation. In the teaching operation, the control unit includes a reference point that is set in advance in an image of the CCD camera and is to be an optical axis of the laser beam, and the selected approximate processing line. An automatic positioning function for calculating a displacement between the reference point and the nearest point, and controlling movement of the work table so as to match the reference point with the nearest point based on the calculated displacement. A laser processing apparatus for controlling the movement of the work table so as to move the reference point in the line direction designated by the designation means after the automatic positioning.