JPH02263587A - Picture input apparatus for laser beam machine - Google Patents

Abstract

PURPOSE:To obtain accurate picture of laser beam machining point for measuring welding line by obtaining the picture of a material to be machined with an ITV camera of a picture input head picking up the picture of the material to be machined. CONSTITUTION:As the picture of the material to be machined can be obtd. by fitting the picture inputting head 24 instead of a laser beam nozzle 23 in a laser beam machine body 21, obstruction to movement and posture of the laser beam machine 21 does not occur and limitation to shape of the material to be machined is eliminated. Further, the ITV camera 25 for obtaining the picture at the welding part in the material to be machined is set on the same axis as the laser beam optical axis. Therefore, the machining point of the material to be machined and its vicinity can be watched with the laser beam axis and the accuracy of position measurement for welding line of the material to be machined is improved. Further, as the material to be machined is lightened with light source under the fixed brightness, the optimum picture without any influence of the outer light can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to an image input device for a laser processing machine, which is used for measuring the position of a weld line on a workpiece in, for example, a CO2 laser processing machine.

(Prior art) Recently, C
Laser processing machines using O2 lasers tend to be widely used. However, since the size of the processing point in a laser processing machine is very small, there is a risk that the quality of the workpiece will deteriorate if the processing point deviates even slightly from the center of the weld line. Therefore, in such a laser processing machine, the position of the weld line is measured in order to enable highly accurate welding.

Here, to explain the welding line of the workpiece using FIG. 6, the cross-sectional image of the workpiece 1 is as shown in FIG. The gap between these members 1a and lb is the weld line 2.

When the workpiece 1 is viewed from the front, the welding line 2 becomes visible as a black line as shown in FIG. Moreover, such a workpiece 1
The position measurement of the welding line 2 is performed by determining the amount of deviation between the position where the laser optical axis hits the workpiece 1 and the center position of the welding line 2 on the workpiece 1.

Conventionally, in a CO2 laser processing machine, a bead sensor that measures the position n1 of the weld line of the workpiece and a bead monitor that monitors the state of the weld line of the workpiece are used to measure the weld line n1 of the workpiece. An image input device having the following is used. In this case, there are two types of beat sensors: one using optical cutting method and the other using triangulation.
The beat sensor using the optical cutting method projects a slit light toward the workpiece 1 from a slit light projector 5 inside the sensor head 4 provided on the side of the laser processing machine main body 3, as shown in FIG. The slit light reflected by the workpiece 1 is captured into the imaging unit 6, and from this captured image, the bead sensor body 7
The bead sensor using triangulation is designed to measure the position of the weld line by using the spot light projecting section 9 of the sensor head 8 installed on the side of the laser processing machine main body 3, as shown in Fig. 8. Projecting a spot light toward the workpiece 1, capturing the light reflected by the workpiece 1 into the optical position detection section 10, and giving this captured data to the bead sensor main body 11,
By scanning here, the weld line position is measured from changes in data displacement.

Further, as shown in FIG. 9, the bead monitor transmits light from a halogen light projecting section 12 provided inside the laser processing machine main body 3 through a beam splitter 13, a mirror 14, and a Zn Se lens 15 for CO2 laser processing. The image of the workpiece 1 is captured by the ITV camera 17 via the Zn Se lens 15, mirror 14, beam splitter 13 and imaging optical system 16, and displayed on the monitor 18. ing. Here, the mirror 14 is driven by a drive mechanism 19.
When capturing an image from the workpiece 1, the mirror 14 is rotated by 45° so that the optical axis is tilted 90'.
During laser processing, the angle of the mirror 14 is changed so that the CO2 laser beam 20 hits the workpiece 1.

(Problem to be Solved by the Invention) However, with these bead sensors that use the optical cutting method or triangulation, the sensor head is installed on the side of the laser processing machine body, so the entire laser processing machine becomes It is large and difficult to handle, and since the weld line is detected in front of the laser processing point, it not only limits the operation and posture of the laser processing machine, but also the shape of the workpiece. causing inconvenience. Also,
The bead monitor uses a Zn Se lens with poor characteristics in the visible light region for imaging, making it difficult to obtain high-quality images, and the optical system is highly restricted.Furthermore, the mirror is mechanically operated, so However, it is difficult to monitor positional deviations from the image displayed on the monitor because the image accuracy deteriorates.

The present invention has been made in view of the above-mentioned circumstances, and allows laser processing points to be set for weld line measurement without interfering with the operation and posture of a laser processing machine, and without restricting the shape of the workpiece. An object of the present invention is to provide an image input device for a laser processing machine that can obtain accurate images.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a laser nozzle that is arranged coaxially with the laser optical axis of the laser processing machine main body, in place of a detachable laser nozzle of the laser processing machine main body. An ITV camera for photographing the workpiece and an image input head containing a light source necessary for photographing with the camera are installed, and the position of the weld line of the wave workpiece is measured from the image obtained from the camera of this image input head. It looks like this.

(Function) As a result, an image input head is attached in place of the laser nozzle on the laser processing machine main body, and an image of the workpiece is obtained, so the operation and posture of the laser processing machine are not hindered, and the There is no restriction on the shape of the workpiece, and since the ITV camera is placed coaxially with the laser optical axis to obtain an image of the weld line part of the workpiece, the workpiece can be processed easily. The point and its surroundings can be seen on the laser axis, improving the accuracy of position measurement of the weld line on the workpiece. Furthermore, since the workpiece can be illuminated with a constant brightness by the light source, it is also possible to obtain an optimal image that is not affected by external light.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of the same embodiment. In the figure, 21 is the main body of the CO2 laser processing machine, and this CO2
The laser processing machine main body 21 allows a laser nozzle 23 (described later) used during laser processing to be detachably attached via a sleeve 22, and also allows an image input head 24 to be attached in place of the laser nozzle 22. In the drawing,
A case is shown in which a human-powered image head 24 is attached.

Here, the sleeve 22 has a cylindrical shape, as shown in FIG. Nozzle 23 or image head 24
A mounting portion 222 is formed. Also, this sleeve 2
2 is attached to the laser processing machine main body 21 so that its central axis coincides with the laser optical axis output from the laser processing machine main body 21. As shown in FIG. 3, the laser nozzle 23 is a hollow inverted conical body whose diameter becomes narrower toward the tip, and a sleeve attachment portion 231 is formed at the large diameter opening end, and this attachment is The portion 231 allows the sleeve 22 to be attached with one touch so that there is no angular deviation and their central axes coincide. The image input radar 24 installed in place of the laser nozzle 23 has a head case 241 in the shape of a hollow inverted cone whose diameter becomes narrower toward the tip, as shown in FIG. The case 241 also has a sleeve attachment portion 242 formed at the large diameter opening end;
This allows the sleeves 22 to be attached with one touch so that their central axes coincide without any angular deviation. In addition, a mount 243 is formed in the hollow part of the head case 241, and the mount 243 crosses the central axis.
An ITV camera 25 and a camera lens 26 for photographing the vicinity of the processing point of the workpiece are fixed. In this case, ITV
The camera 25 and camera lens 26 are arranged in a line on the central axis of the hollow portion of the head case 241 so as to coincide with the laser optical axis output from the laser processing machine main body 21. Further, a plurality of LEDs 27 are housed inside the head case 241 on the small diameter opening side. These LE
D27 is for illuminating the surface of the workpiece with the brightness necessary for photographing with the ITV camera 25, and is an annular flange 2.
8 at equal intervals.

Note that the head case 2 of such an image input head 24
41 is provided with a window (not shown) for finely adjusting the focus and aperture of the camera lens 26, but a cover 29 is provided on the head case 241 via a ring 30 to keep this window closed at all times. There is.

Returning to FIG. 1, a camera controller 31 and a light source drive circuit 32 are connected to the image input head 24 via a cable 33. Here, the camera controller 31 controls the TV camera 25 and outputs the image of the workpiece obtained from the ITV camera 25 as a video signal containing a vertical synchronization signal and a horizontal synchronization signal. Further, the light source drive circuit 32 supplies a drive current for lighting the LED 27, and also makes this drive current variable so that the brightness of the LED 27 can be adjusted.

The image output from the camera controller 31 is given to an image processing device 34. This image processing device 34 has an image input section 341, an image processing section 342, a monitor 343, and a laser processing machine controller 344, as shown in FIG. In this case, a video signal from the camera controller 31 is taken into the image input section 341, and the image processing section 34
2, the weld line is recognized from the image of the workpiece and the position of the weld line is measured. The measurement results from the image processing unit 342 are displayed on the monitor 343, and the measured position is converted into coordinates of the laser processing machine and provided to the laser processing machine controller 344. This laser processing machine controller 344 is configured to give a control signal to the laser processing machine main body 21 so that the welding line of the workpiece and the laser optical axis coincide with each other based on the given coordinate data.

Next, the operation of the embodiment configured as described above will be explained.

First, instead of the laser nozzle 23, the image input head 24 is attached to the sleeve 22 of the CO2 laser processing machine main body 21. In this case, the image input head 24 is attached to the sleeve 22 by a portion 242 at the large diameter open end of the head case 241 with one touch so that there is no angular deviation and their central axes coincide.

Next, the image input head 24 is made to face the welding surface of the workpiece, and a driving current is applied to the LEDs 27 by the light source driving circuit 32 to light up these LEDs 27 to illuminate the surface of the workpiece. In this case, the drive current is varied depending on the brightness around the workpiece, and the LED 27
to control the brightness of the

From this state, when the image input head 24 is moved along the processing part of the workpiece by operating the laser processing machine main body 21, an image of the vicinity of the processing point of the workpiece photographed by the ITV camera 25 is sent to the camera controller 31. The camera controller 31 outputs a video signal containing a vertical synchronization signal and a horizontal synchronization signal.

A video signal from this camera controller 31 is given to an image processing device 34. Then, the video signal is captured by the image processing unit 341 and sent to the image processing unit 342, where the weld line is recognized from the image of the workpiece and the position of the weld line is measured. In addition, the image processing unit 34
The measurement results at step 2 are displayed on the monitor 343, and
The measured position is output as coordinate data of the laser beam machine and given to the laser beam machine controller 344. Then, the laser processing machine controller 344 outputs a control signal to match the welding line of the workpiece according to the coordinate data with the laser optical axis, and sends it to the laser processing machine main body 21.

Thereafter, the laser nozzle 23 is attached to the laser processing machine main body 21 and actual laser processing is performed.
The welding line is controlled and operated by the control signal from 4 so that the laser optical axis coincides with the welding line.

Therefore, in this way, the human image head 24 can be attached in place of the laser nozzle 22, so there is no restriction on the shape of the workpiece, and images can be input without interfering with the operation and posture of the laser processing machine. become. Also, although it is not possible to capture an image of the workpiece during laser processing, when the image input head 24 is attached, the ITV camera 25 is placed on the laser optical axis output from the laser processing machine main body 21. Therefore, the center of the image coincides with the laser optical axis, which means that the image of the processing point on the workpiece and its surroundings can be obtained as if it were on the laser axis, allowing highly accurate weld line position measurement. be able to. Also, LED
Since the brightness of 27 can be controlled to an optimal state by the optical drive circuit 32, it is also possible to obtain an image that is not affected by external light.

Furthermore, since the workpiece is directly photographed by the ITV camera 25, it is possible to prevent deterioration in image quality compared to conventional Zn Se lenses, and to eliminate errors caused by mechanically manipulating conventional mirrors. Preventable, ITV
Images can be obtained from the camera 25 according to its performance.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications without changing the gist.

[Effects of the Invention] The present invention provides an I'T that photographs the workpiece in place of the laser nozzle of the main body of the laser processing machine, which has a detachable laser nozzle.
An image input head containing a V-camera and a light source necessary for photographing with the camera is installed, and the IT of this image input head is installed.
Since the image of the workpiece is obtained using a V camera,
The operation and posture of the laser processing machine are not hindered, and the shape of the workpiece is not restricted. Moreover, since the ITV camera that captures the image of the workpiece is placed coaxially with the laser optical axis, it is possible to obtain an accurate image of the additional point on the workpiece and its surroundings on the laser axis. , it is possible to improve the accuracy of position measurement of the weld line of the workpiece. Furthermore, the brightness of the LED can be easily controlled using the light source drive circuit, and the workpiece can be illuminated with optimal brightness, making it possible to create optimal images that are less susceptible to external light and free from unnecessary aberrations and errors. You can also get it.

[Brief Description of the Drawings] Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is a sectional view of a sleeve used in the embodiment, and Fig. 3 is a laser beam used in laser processing. 4 is a sectional view showing the image input head used in the same embodiment, FIG. 5 is a block diagram showing the image processing device in the same embodiment, and FIG. 6 is a workpiece and welding line. Figure 7 is a schematic configuration diagram of a bead sensor using the conventional optical cutting method, Figure 8 is a schematic configuration diagram of a bead sensor using conventional triangulation, and Figure 9 is a diagram for explaining the conventional bead sensor. FIG. 2 is a schematic configuration diagram of a bead monitor. 21... Laser processing machine main body, 22... Sleeve, 2
3... Laser nozzle, 24... Image input head, 2
41...Head case, 242...Sleeve mounting part, 243...Mount, 25...ITV camera,
26...Camera lens, 27...LED, 29...
- Cover 31... Camera controller, 32... Light source drive circuit, 34... Image processing device, 341... Image input section, 342... Image processing section, 343... Monitor, 344...・Laser processing machine controller.

Claims (1)

[Claims] A laser processing machine main body with a detachable laser nozzle, and a laser processing machine provided in place of the laser nozzle of the laser processing machine main body and arranged coaxially with the laser optical axis of the laser processing machine main body to photograph the surface of the workpiece. It is characterized by comprising an image input head that houses an ITV camera and a light source necessary for photographing with the camera, and an image processing means that measures the position of the weld line of the workpiece from the image obtained from the camera. Image input device for laser processing machines.