JPS6123575A - Weld arc monitoring method - Google Patents

Abstract

PURPOSE:To obtain a television picture with the contrast checked as a whole by arranging an optical filter to partially dim the image of the high luminance portion of the arc at the front of the image pickup surface of the camera when the weld arc is picked up by the television camera. CONSTITUTION:The television camera 8 to pick up the weld arc 7 and the weld arc section 7 are installed to the mounting arm 2 and the relative position is fixed. At the front of the image pickup surface of the camera 8, a dimmer filter 12 partially different in transmittance is provided, an the filter 12 consists of a portion 13 with higher transmittance and another portion 14 with lower transmittacne. This checks the contrast between the neighborhood (a) fo the arc 7 which is most clearly displayed and the other portion (b), making it possible to display clearly the other portion in the groove.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of application in the industry] The present invention relates to a method for monitoring a bath arc area in which a television camera is also used to monitor the welding arc area.

[Prior art]

Conventionally, the welding arc was monitored in the following ways: (1) The operator directly observed the arc using a welding light-shielding surface.

■ In automatic or semi-automatic bath welding, the operator observes an arc image projected onto an optical device attached to the welding machine.

■ A television camera is attached to the welding machine, and the arc portion is shown as an image on the television screen, and the operator observes the image on the television screen.

This is done using methods such as

By the way, the method (2) above is often used as an arc part monitoring device for automatic and semi-automatic welding machines because it allows remote monitoring of the arc part.

However, the disadvantage is that sufficient information cannot be obtained about the inside of the groove other than the arc part because the contrast ratio between the arc part and the rest is extremely large. Note that the same applies to method (2) above.

This drawback is due to the fact that the aperture of the amount of incident light is adjusted to match the brightest part of the subject, that is, the arc, in order to prevent damage to the imaging unit due to an excessive amount of light incident on the image pickup tube of a television camera. , is unavoidable.

Therefore, a television camera using a CCD (charge-coupled device) image pickup element, which does not cause burn-in damage to the image pickup section, has been developed and is used to monitor the arc section.

However, for high-brightness objects, blooming, which is characteristic of CCDs, may occur, so it cannot be said that a perfectly clear surface image can be obtained. There are also examples in which the video signal of a television camera using CCDe is nonlinearly processed using a logarithmic amplifier to enhance dark information, but this results in a surface image with a degraded signal-to-noise ratio.

[Purpose of the invention]

This invention was invented based on the above-mentioned background, and when the welding arc part is imaged with a television camera and observed on a monitor TV, not only the arc part but also other parts within the groove can be seen. The present invention provides a method for monitoring a welding arc portion by displaying it clearly.

[Structure of the Invention] The present invention fixes the relative positions of a television camera that images a welding arc portion and a welding torch, and images a high-intensity portion of the arc on the image pickup surface in front of the image pickup surface of the television camera. This method of monitoring a welding arc portion is characterized by arranging an optical filter that partially attenuates the light in the welding arc portion so as to obtain a television screen image with suppressed contrast as a whole.

〔Effect of the invention〕

However, according to the present invention, it is now possible to sufficiently observe the condition of the groove wall, the front layer bead, or the molten pool other than the arc portion, which was previously difficult.

Furthermore, it is also possible to manually finely adjust the torch aiming position based on the surface image on the television monitor.

〔Example〕

The invention of Tsukinito will be explained in detail with reference to the drawings showing one embodiment thereof.

FIG. 1 shows a welding arc monitoring device according to the present invention, in which (1) is a welding torch held at one end of a mounting arm (21), and (3) is a welding wire (4).
The reel (5) is the wire wound from the reel (3).
41 is drawn out and the wire (4) is supplied to the base metal (6) through the torch (1), (7) is the welding arc part, and (8) is the mounting arm (held at the other end of 21). This is a television camera for monitoring the arc portion, and its relative position to the torch il+ is fixed. (9) is a signal cable that leads the video signal of the television camera (8) to the television monitor 00.

Note that the bath-contact power source is omitted in this figure.

FIG. 2 shows an example of an arc portion image displayed on the screen (11) of the television monitor OQ.

However, normally, the arc portion (7) is displayed the brightest on the screen 1Ill of the television monitor αQ. Further, the contrast between the area near the arc (a) and the other area (b) is thick, and only the area near the arc (a) is displayed on the screen (11) of the television monitor 01. The reason for this is that the contrast of the subject is greater than the dynamic range (usually 30 to 40 dB) of the imaging unit of the television camera (8).

In the past, the contrast of the entire screen could be suppressed by reducing the amount of light irradiated onto the imaging surface of the television camera (8), which corresponds to the area near the arc area (a) in Figure 2, and the arc area (7) In addition to this, other parts of the image can also be displayed in detail on both sides (11) of the television monitor αO.

FIG. 3 shows a neutral density filter α power having partially different transmittances, and there is a portion 041 with low transmittance in the center of a portion (13) with high transmittance.

The filter f+2)i shown in FIG. The part near the axis is dimmed and the imaging unit (10
will be played. Note that the imaging unit (151) and the filter (12
As the distance from the filter (121) increases, the effect of the filter (121) becomes weaker, but if the aperture of the TV camera (8) lens [+81] is increased, the depth of focus becomes deeper, so you can obtain the same effect as when they are in close contact. In Fig. 4, numeral 1 is a neutral density filter, and 1 is a protective glass for the lens system against bath contact sputtering.

[Brief explanation of drawings]

The drawings show one embodiment of the welding arc monitoring method of the present invention, in which Fig. 1 is a front view of the device, Fig. 2 is a screen view of a television monitor, Fig. 3 is a front view of a filter, and Fig. 4 is an optical It is a diagram. (1)...Welding torch, (2)...-Mounting arm, (7
)...Arc M, ts+...TV camera, Q(1.
・TV monitor, 111 screen, 1121...filter.

Claims (1)

[Claims] (1) The relative positions of a television camera that images the welding arc and the welding torch are fixed, and a portion of the imaging surface where the high-intensity portion of the arc is imaged is partially set in front of the imaging surface of the television camera. A welding arc monitoring method characterized by arranging a light attenuating optical filter to obtain a television screen image with suppressed contrast as a whole.