JP3169554B2 - Disturbance detection method during welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a disturbance which causes a welding defect during automated welding.

[0002]

2. Description of the Related Art When performing automated TIG welding,
No detection of disturbances, especially winds, that cause welding defects was performed, and inspections for defects were usually performed after welding. The wind blown during welding causes welding defects such as blow holes.

[0003]

As described above, since the presence or absence of a welding defect is inspected after the end of welding, if the defect position is near the welding start point, the defect is located over the entire welding line. Repair welding must be performed, which is very troublesome.

[0004] As a method of detecting a wind as a disturbance during welding, there is a method of monitoring by a TV monitor by an operator, but it is very inefficient. Therefore, the present invention
An object of the present invention is to provide a disturbance detection method capable of easily detecting a disturbance.

[0005]

In order to solve the above-mentioned problems, a method for detecting disturbance during welding according to the present invention uses a sound-collecting microphone to collect welding sounds generated from the vicinity of a welded portion during TIG welding. 20 of the welding sounds
This is a method of detecting disturbance due to wind by detecting a sound pressure level near kHz.

[0006] According to the above configuration, the high or low of the sound pressure level is determined based on the welding sound near 20 kHz among the welding sounds generated at the time of TIG welding, and whether the wind which causes disturbance is blowing. Therefore, it is possible to automatically detect the presence or absence of a wind as a disturbance.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for detecting disturbance during welding according to the present invention will be described below with reference to FIGS.

First, an apparatus used for detecting disturbance, ie, wind, during welding during TIG welding will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an automatic welding robot device having a torch 1a for TIG welding at the tip, and a disturbance detecting device 2 for detecting a wind acting as a disturbance in the torch 1a.

The disturbance detecting device 2 has a predetermined frequency, that is, 20 kHz, from a sound collecting microphone 11 arranged near the torch 1a and a welding sound picked up by the sound collecting microphone 11.
Bandpass filter 1 that allows only nearby welding sound to pass
2, a sound pressure detector 13 which detects welding sound having a high sound pressure level passing through the band-pass filter 12 and outputs the detection to the automatic welding robot apparatus 1 side.
It is composed of

[0010] Here, the wind acting as a disturbance (for example, 4 to 5 m
The reason why attention was paid to the welding sound near 20 kHz in order to detect the (wind / sec or more wind) will be described. That is, when the welding sound at the time of normal TIG welding and the welding sound at the time of blowing wind are measured and the respective frequencies are analyzed, FIG.
It becomes like the graph of.

As can be seen from the graph of FIG. 2, when the wind blows, the sound pressure becomes higher as a whole, but the sound pressure especially around 20 kHz becomes remarkably higher for any shield gas. You can clearly see that

In FIG. 2, the shielding gases used are ArHe gas (argon / helium gas) and He gas.
Gas (helium gas) and Ar gas (argon gas)
It is. As for ArHe gas, a case where a panel waveform current is used is also shown.

FIG. 3 is a graph showing the difference between the welding sound pressure when the wind blows and the welding sound pressure during normal welding as a result of the frequency analysis of the welding sound. From this graph, it can be clearly understood that the welding sound when the wind blows is high around 20 kHz for any shielding gas.

Therefore, in practice, it is not necessary to analyze the frequency of the welding sound over a wide range. In order to detect the wind that becomes a disturbance, it is necessary to detect the presence or absence of the welding sound near 20 kHz during welding. It turns out to be good.

On the basis of this principle, the present invention has arrived at a method for detecting wind as a disturbance. Note that FIG.
3 and FIG. 3, the welding conditions under normal conditions are as follows.
At 0 A, the arc length was 2 mm, the flow rate of the shielding gas was 15 liters / min, and the wind at the time of disturbance was 5.5 m / sec.

Next, an operation of detecting the wind as a disturbance by the disturbance detection device will be described. That is, TIG
At the time of welding, the welding sound is constantly picked up by the sound collecting microphone 11, and when the welding sound passes through the band-pass filter 5, only the one near 20 kHz is selected. The sound pressure level is input to the pressure detector 13, and the level of the sound pressure level around 20 kHz is determined here.

When it is detected that this 20 kHz sound pressure level is high, this is input to the automatic welding robot apparatus 1, and based on this input, the automatic welding robot apparatus 1 prevents the occurrence of defects due to wind. Measures are taken promptly. For example, welding is temporarily interrupted until the wind is weakened.

That is, as compared with the case where the welding defect is known after the end of the TIG welding as in the conventional case, the efficiency is very high.
Labor saving can be achieved.

[0019]

As described above, according to the disturbance detection method of the present invention, of the welding sound generated during TIG welding, 20 kHz
Based on the nearby welding sound, the sound pressure level is determined to be high or low, and it is determined whether the wind that causes disturbance is blowing. Therefore, on the automatic welding robot device side,
Preventive measures against the occurrence of defects due to wind can be taken promptly.

That is, as compared with the conventional case where the welding defect is known after the end of the TIG welding, the work efficiency is much higher and the labor saving is achieved as compared with the case where the monitoring is always performed by a person. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a device used in a disturbance detection method according to an embodiment of the present invention.

FIG. 2 is a graph showing a frequency analysis result of welding sound in the embodiment.

FIG. 3 is a graph showing a difference between a welding sound pressure at the time of a disturbance and a welding sound pressure at a normal time in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic welding robot apparatus 1a Torch 2 Disturbance detection apparatus 11 Sound collecting microphone 12 Band pass filter 13 Sound pressure detector

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Morihiko Osawa Hitachi Shipbuilding Co., Ltd. 5-28 Nishikujo, Konohana-ku, Osaka-shi, Osaka (56) Reference JP-A-7-299566 (JP, A) Kaihei 5-50244 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01H 3/10 B23K 9/095 515 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A welding sound generated from the vicinity of a welded portion is collected by a sound collecting microphone at the time of TIG welding, and a sound pressure level near 20 kHz is detected from the collected welding sound to reduce disturbance due to wind. A method for detecting disturbance during welding, characterized by detecting.