JPH0825040A - Method for monitoring welding condition and instrument thereof - Google Patents

Abstract

PURPOSE:To easily execute the monitoring of welding condition accompanied with the automation of a welding work of an arc welding, etc., by picking up an image of the welded part with a monitoring camera by infrared ray, outputting video signals outputted from the monitoring camera with a monitor and executing the monitoring of the welded part. CONSTITUTION:Only the infrared ray in the light coming from the welded part 6 is transmitted through an infrared ray transmitting filter 9, and since the image of the welded part 6 is picked up with the monitoring camera 8 only by the infrared ray, in the case of observing the video of the welded part 6 picked up with the monitoring camera 8 through the monitor 12 at the time of welding, the arc 10 and the position except the arc can be identified. By this method, the monitoring of the welded part 6 at the time of welding can be executed. This reason is because the extremely intense infrared ray is not generated from the arc 10 generated at the time of welding and therefore, the extremely large difference to the infrared ray quantity between the arc part 10 and the part except the arc part, is not developed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to provide a novel welding condition monitoring method and apparatus capable of easily monitoring the welding condition with the automation of welding work such as arc welding or gas welding. It is a thing.

[0002]

2. Description of the Related Art Welding work must be performed while monitoring the welding condition.

However, since the visible light generated by the arc or the welding flame is very strong in the welding operation, the difference in the illuminance between the arc or the welding flame and other parts during welding (when the arc or the welding flame occurs). Is excessive, and the torch position, the arc state, the welding beat state, the molten pool position, etc., become relatively dark.

When an attempt is made to monitor a welded portion in an automatic welding machine with a surveillance camera, the arc is too strong during welding and other parts cannot be projected as an image, and therefore surveillance with a surveillance camera is not possible. It was

That is, when an image of a welded portion is to be photographed by a surveillance camera during welding, visible light generated by an arc or a welding flame is very strong, so that the surveillance camera must be narrowed down for photography. In this way, it is not possible to capture an image of a welded part other than a relatively darkened arc or welding flame.

Therefore, the following means can be considered in order to capture an image of the welded portion other than the arc with a surveillance camera even during welding.

The first means is to weaken the arc by controlling the arc current or arc voltage, the distance between the torch and the base metal, etc., and in such a welding state, the welded portion is photographed by the monitoring camera and It is possible to monitor.

In this case, by weakening the arc, it is possible to eliminate the extreme difference in illuminance between the arc at the welded portion and the other portions, and it is possible to photograph the two during welding.

As a second means, the periphery of the welded portion and the tip of the welding torch are illuminated with a high-capacity light, and these are photographed by a high-performance surveillance camera through an ND filter having a low light transmittance. Can also be considered.

In this case, the entire weld is made to have a high illuminance, and the illuminance between the arc or welding flame and the other parts is made to have a high illuminance but no extreme difference, and the ND filter is used to illuminate them. Can be reduced to enable the shooting.

[0011]

However, in the above first means, the welding conditions such as weakening the arc or the welding flame must be changed only to monitor the welding state. Is non-uniform and the arc during welding or the welding flame itself cannot be monitored.

The second means requires a high-capacity light and a special surveillance camera with high sensitivity for narrowing the light quantity with an ND filter, which makes the equipment larger and There is a problem that it causes an increase in equipment cost.

[0013]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a welding arc and a welding flame include infrared light, an infrared light transmitting filter that transmits only infrared light, and a solid-state image sensor ( The CCD) is also sensitive to infrared light and can be output as a luminance signal, and the like.

In order to solve the above-mentioned problems, the welding state monitoring method of the present invention irradiates the welded portion with the infrared light generating means, and at the same time, the infrared ray of the light coming from the welded portion is transmitted through the infrared light transmitting filter. Only the light is transmitted, the welding portion is photographed with infrared light by a monitoring camera, and the video signal output from the monitoring camera is output by the monitor to monitor the welding portion.

Further, the welding condition monitoring apparatus of the present invention includes an infrared light generating means for irradiating the welded portion, a monitoring camera for photographing the welded portion, and an arrangement between the monitoring camera and the infrared light generating means. It is provided with an infrared light transmission filter material that is provided and transmits only infrared light, and a monitor that outputs a video signal output from the surveillance camera.

[0016]

Therefore, according to the welding state monitoring method and the apparatus thereof of the present invention, since the welding portion is imaged by the monitoring camera only by its infrared light, the welding portion is imaged by the monitoring camera at the time of welding (after arc or welding flame is generated). When the video of the welded portion is viewed on the monitor, the arc or welding flame and the other portion can be identified, and thus the welded portion can be monitored during welding.

This is because an extremely strong infrared light is not generated from the arc or welding flame generated during welding, and therefore, the amount of infrared light of the arc or welding flame and other portions during welding is extremely high. This is because there is no significant difference.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the welding condition monitoring method and apparatus of the present invention will be described below with reference to the illustrated embodiments. Each of the illustrated embodiments shows an example in which the present invention is applied to an automatic arc welding apparatus.

FIG. 1 shows a first embodiment of the welding condition monitoring apparatus of the present invention.

Reference numeral 1 denotes an automatic arc welding apparatus, the welding torch 2 of which is arranged facing the welding groove 4 of the welding base materials 3 and 3 with an appropriate interval, and the welding torch 2 is not shown. The slide mechanism allows the welding groove 4 to move along the welding line.

Reference numeral 5 is a monitoring device for monitoring the welding state, and irradiates the welding portion 6, that is, the tip of the welding torch 2 and the periphery of the welding groove 4 of the welding base materials 3 and 3 with infrared light. Infrared light generating means 7, a monitoring camera 8 for photographing the welded portion 6, and an infrared light transmitting filter 9 for transmitting only infrared light of the welded portion 6 and allowing the infrared light to enter the monitoring camera 8. Etc.

The infrared light generating means 7 is, for example, an infrared lamp or the like, and is arranged so as to mainly irradiate the welded portion 6. The wavelength of infrared light emitted by the infrared light generating means 7 is set to, for example, about 1000 nm, which is the spectral sensitivity characteristic of the solid-state image sensor (CCD) of the surveillance camera 8 and the red light generated by the arc 10. It depends on the band of outside light.

The monitoring camera 8 uses a CCD as an image sensor, and is arranged with the welded portion 6 as an object and in a direction orthogonal to the welding line of the welding groove 4. Such a surveillance camera 8 may be an ordinary home video camera, and the CCD used in such a video camera has a spectral sensitivity characteristic of about 400 nm to 1200 nm. The surveillance camera 8 may be any one as long as it is sensitive to infrared light, and may use something other than a CCD as an image sensor.

The infrared light transmitting filter 9 is attached to the front end of the lens barrel of the surveillance camera 8 and transmits only infrared light. The transmission wavelength of the infrared light transmission filter 9 is set to 1000 nm or more.

Reference numeral 11 denotes a reflecting mirror having a shape in which a part of a cylindrical body provided so as to surround the periphery of the welded portion 6 is cut out, and the inner surface of the reflecting mirror 11 serves as a reflecting surface. This is for reflecting the light of the arc 10 generated at some time on the welded portion 6 to increase the amount of light with which the welded portion 6 is irradiated.

Further, the infrared light generating means 7 and the monitoring camera 8 are arranged corresponding to the cutout portion 11a of the reflecting mirror 11,
The welding part 6 can be irradiated or photographed, respectively.

The infrared light generating means 7 and the monitoring camera 8 are also provided.
The reflecting mirror 11 is moved together with the welding torch 2, and the welding torch 2 causes the groove 4 of the base materials 3 and 3 to move.
4 when these infrared light generating means 7,
The monitoring camera 8 and the reflecting mirror 11 follow the welded portion 6.

Before the start of welding, however, the infrared light emitted by the infrared light generating means 7 is reflected by the welding portion 6 and enters the surveillance camera 8 through the infrared light transmitting filter 9. .

During welding, the welding torch 2 and the base metal 3,
Infrared light generated by the arc 10 and the infrared light generated by the infrared light generating means 7 are reflected at the welded portion 6,
Further, infrared light generated from the arc 10 is directly incident on the surveillance camera 8 via the infrared light transmission filter 9.

At the time of welding, since there is no extreme difference in the amount of light between the infrared light generated by the arc 10 and the infrared light reflected by the infrared light generating means 7 and the reflecting mirror 11, other than the arc 10 The welded part 6 does not become relatively dark.

The infrared light incident on the surveillance camera 8 is C
The image is picked up by a CD, and the video is used as a video signal. Such a video signal is obtained by detecting infrared light with a CCD, and has no color signal but only a luminance signal.

An image of infrared light of the welded portion 6 picked up by the CCD of the surveillance camera 8 is output from the surveillance camera as a video signal. When the video signal is projected on the monitor 12, the arc 10 and It is possible to identify the welded portions 6 other than.

In the above embodiment, since the reflecting mirror 11 is used, the infrared light of the arc 10 generated at the time of welding can be used as the light for irradiating the welded portion 6, and the whole of the welded portion 6 can be used. The amount of infrared light can be increased, the irradiation of infrared light by the infrared light generating means 7 can be suppressed during welding, and power consumption can be reduced.

Further, turning on / off of the infrared light generating means 7 may be controlled in synchronization with the generation of the arc 10.

FIG. 2 shows a second embodiment 1A of the welding condition monitoring apparatus of the present invention.

The second embodiment differs from the first embodiment in that the welded portion 6 is covered with a box made of an infrared light transmitting filter, and the front portion of the camera lens in the above embodiment is covered. Since it is only the point that the infrared light transmission filter attached to the above is replaced, only the main part is shown in the drawing, and the explanation is given only for the above difference, and other parts are described in the respective parts of the drawing as the first part. The description thereof will be omitted by giving the same reference numerals to the similar portions in the welding condition monitoring apparatus according to the first embodiment.

Reference numeral 13 denotes a box body made of an infrared light transmitting filter material which transmits only infrared light. The box body 13 is arranged so as to cover the entire welded portion 6 including the welding torch 2.

The infrared light generating means 7 and the reflecting mirror 11 are located outside the box body 13.

The infrared light generating means 7 and the reflecting mirror 1
The position of 1 may be outside or inside the box 13, but in order to prevent spatter adhesion during welding, the box 1
It is preferable to locate it on the outside of 3.

Reference numerals 14 and 14 denote surveillance cameras. One of the surveillance cameras 14 has a photographing direction perpendicular to the traveling direction of the welding torch 2, and the other surveillance camera 14 has a photographing direction.
Is the welded part 6 from the front side in the traveling direction of the welding torch 2.
Are arranged to shoot each.

However, even in the monitoring device 5A in the second embodiment, the welding portion 6 is photographed by infrared light and the monitor 12 monitors the same as in the monitoring device 5 in the first embodiment. Since the projected image can be discriminated between the arc 10 and the welded portion 6 other than that, the welded portion 6 can be monitored and the welded portion 6 can be detected by the infrared light transmitting filter. Since it is covered with the box body 13 made of a material, visible light and ultraviolet rays are absorbed by the box body 13 and therefore they do not leak to the outside, so that the atmosphere of welding work can be improved.

The wavelength of infrared light used for photographing in each of the above embodiments is determined by the type of arc or welding flame and the sensitivity characteristics of the CCD of the surveillance camera.

That is, it is possible to select a frequency band of infrared light emitted from an arc or a welding flame, which is relatively weak, and a band having a higher sensitivity in relation to the sensitivity characteristic of the CCD of the surveillance camera. desirable. The former is because the difference in the amount of infrared light at the arc or welding flame during welding and the other welds is smaller in the image captured by the surveillance camera, which makes it easier to identify the two. This is because the more sensitive the band, the clearer the image.

[0044]

As is apparent from the above description, according to the welding state monitoring method of the present invention, the welding state of the welded portion is monitored, and the welded portion is irradiated with infrared light generating means. At the same time, only the infrared light of the light coming from the weld is transmitted through the infrared light transmitting filter, the weld is photographed by the monitoring camera by the infrared light, and the video signal output from the monitoring camera is monitored by the monitor. The feature is that the output is performed and the welded portion is monitored.

According to the welding condition monitoring apparatus of the present invention,
A device for monitoring the welding state of a welded part, which comprises infrared light generation means for irradiating the welded part, a surveillance camera for photographing the welded part, and between the surveillance camera and the infrared light generation means. It is characterized in that it is provided with an infrared light transmitting filter material that is provided and transmits only infrared light, and a monitor that outputs a video signal output from the surveillance camera.

Therefore, according to the welding state monitoring method and the apparatus thereof of the present invention, since the welding portion is imaged by the monitoring camera only by its infrared light, the welding camera is imaged at the time of welding (after arc or welding flame is generated). When the video of the welded portion is viewed on the monitor, the arc or welding flame and the other portion can be identified, and thus the welded portion can be monitored during welding.

In each of the above embodiments, the welding condition monitoring device of the present invention has been described as an example in which it is used as a monitoring device of an arc welding machine, but the present invention is not limited to this, and a monitoring device of a gas welding machine or the like. Can also be used for

Further, the structures and shapes of the respective parts shown in the above-mentioned embodiments are merely examples of the embodiment when the present invention is carried out, and the technical scope of the present invention is limited by these. Should not be construed in the open.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment in which a welding condition monitoring device of the present invention is applied to a monitoring device for an arc welder.

FIG. 2 is a schematic perspective view showing a second embodiment in which the welding condition monitoring device of the present invention is applied to a monitoring device of an arc welding machine.

[Explanation of symbols]

 2 Welding torch 5 Monitoring device 6 Welding part 7 Infrared light generating means 8 Monitoring camera 9 Infrared light transmission filter 11 Reflector 12 Monitor 5A Monitoring device 13 Box 14 Monitoring camera

Claims (5)

[Claims] 1. A method for monitoring a welding state of a tip end portion of a welding torch and its periphery (hereinafter referred to as "welding portion"), which comprises irradiating the welding portion with an infrared light generating means and infrared light. Only infrared light of the light coming from the welded portion is transmitted through the transmission filter, the welded portion is photographed by the monitoring camera by the infrared light, and the video signal output from the monitoring camera is output by the monitor to detect the welded portion. A welding state monitoring method characterized in that monitoring is performed. 2. An apparatus for monitoring a welding state of a tip portion of a welding torch and its periphery (hereinafter referred to as "welding portion"), the infrared light generating means for irradiating the welding portion, and the welding portion. A monitoring camera for photographing, an infrared light transmitting filter material which is disposed between the monitoring camera and the infrared light generating means and transmits only infrared light, and an image signal output from the monitoring camera are output. A monitor for welding. 3. The welding condition monitoring apparatus according to claim 2, wherein the infrared light transmitting filter material is an infrared light transmitting filter attached to the front part of the lens of the surveillance camera. apparatus. 4. The welding condition monitoring apparatus according to claim 2, wherein the infrared light transmitting filter material has a box shape, and the welding portion is substantially covered with the infrared light transmitting filter. Welding condition monitoring device. 5. The welding condition monitoring apparatus according to claim 2, 3, or 4, wherein a reflecting mirror is arranged in the vicinity of the welded portion and reflects the light of an arc or welding flame during welding. A welding condition monitoring device characterized in that the welded portion is irradiated with light.