JPH0122070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding position detection method in arc welding, and more specifically, an electrode wire is used as a contact, the electrode wire is moved, and the position where the wire contacts the workpiece is detected. The present invention relates to a method for detecting a welding position in arc welding, in which the optimum welding position of an electrode wire is determined based on the detected position.

FIG. 1 conceptually shows a conventionally used automatic arc welding machine (weaving welding machine). In the figure, 1 is an electrode wire, 2
is a holder for the electrode wire; 3 is a drive device for horizontally moving the holder; 4 is a holder 2;
5 is a weaving device; 6 is a control device that controls both of the above-mentioned driving devices, the weaving device, a welding power source, a position detection power source, etc.; 7, 8... objects to be welded.

In this automatic arc welding machine, an electrode wire is used as a contact, and the wire is first lowered by a vertical drive device 4, as shown in FIG. Detects the change in impedance (resistance, voltage, current) at the time, and stops the operation of the vertical drive device 4 (point a).
Then, by operating the vertical drive device 4 in the opposite direction,
Return wire 1 by the set amount (point b). Activate the horizontal drive device 3 to move the wire 1 parallel to the workpiece 7, and when the tip of the wire 1 comes into contact with the workpiece 8, an impedance change is detected in the same way as above, and the wire 1 is moved horizontally. The operation of the drive device 3 is stopped (point c). Subsequently, the horizontal drive device 3 is operated in the opposite direction to return the wire 1 by a set amount (point d). In this way, the obtained point d becomes the welding position of the electrode wire 1. Once the electrode wire 1 is set at the optimum position, the position detection circuit is switched to the welding power source circuit, and welding preparations are completed. In this automatic welding machine, during welding work, the electrode wire 1 is swung by the weaving device 5 at a constant amplitude and frequency as shown in FIG. All of the above-mentioned devices including the above are controlled by the control device 6.

A conventional method for detecting the welding position of the electrode wire 1 in such an automatic welding machine, that is, the electrode wire 1
In the welding position detection method using as a contact,
Since the impedance change when the tip of the electrode wire 1 contacts the objects 7 and 8 to be welded is detected,
If the surfaces of the objects 7 and 8 to be welded are oxidized or if paint is attached to the surfaces, there is a risk that detection may become difficult.

The present invention has solved these problems, and is characterized by applying vibration to the electrode wire when detecting the optimal welding position of the electrode wire, and making contact with the workpiece while vibrating the wire. The purpose is to make it possible.

The present invention will be described below with reference to embodiments shown in the drawings. The welding position detection method in arc welding according to the present invention uses the electrode wire 1 as a contact, moves the electrode wire 1, and moves the electrode wire 1 to the position where the wire contacts the workpieces 7 and 8 (point a in FIG. 2). , c), and set the optimum welding position of the electrode wire from the detected position.In the arc welding welding position detection method, the electrode wire 1 is moved at a constant amplitude and frequency as shown in FIG. The object is to contact the objects 7 and 8 to be welded while vibrating them.

In this way, the electrode wire 1 subjected to vibration is
When the wire comes into contact with the workpiece 7, for example, as shown in FIG.
a to remove obstacles such as an oxide film and paint on the surface to ensure electrical contact with the electrode wire 1. Note that in FIGS. 4a and 4b, the action of the vibrating electrode wire 1 is exaggerated in order to clearly show the action, but in reality, the tip of the electrode wire 1 is slightly bent, etc., making it difficult to detect the position. Errors are rarely a problem. Further, the vibration of the electrode wire 1 may be applied by a weaving device 5.

In the above embodiment, the electrode wire 1 is moved parallel to the objects to be welded 7 and 8, but in the method of the present invention, the electrode wire 1 is moved back and forth between the objects to be welded 7 and 8. , 8 may be moved on a trajectory corresponding to the base of an isosceles triangle with equilateral sides,
The movement mode of the electrode wire 1 does not matter. Further, the method of the present invention is applicable not only to weaving welding but also to any general arc welding.

As described above, the welding position detection method in arc welding according to the present invention allows the tip of the electrode wire to be detected even when the surface of the object to be welded is covered with an oxide film etc. Since they are removed, the tip of the electrode wire reliably contacts the surface of the workpiece, and therefore the point (position) at which the electrode wire contacts the workpiece can be reliably detected.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram of an automatic arc welding machine, Figure 2 is a diagram showing its welding position detection function, Figure 3 is a diagram showing a welding position detection method according to the present invention, and Figures 4a and b are It is a figure showing the effect. DESCRIPTION OF SYMBOLS 1... Electrode wire, 2... Torch, 3... Horizontal direction drive device, 4... Vertical direction drive device, 5...
...Weaving device, 6...Control device.

Claims (1)

[Claims] 1. A welding position detection method for arc welding that uses an electrode wire as a contact, moves the electrode wire, detects the position where the wire contacts the workpiece, and sets the optimal welding position of the electrode wire from this position. A method for detecting a welding position, characterized in that the electrode wire is brought into contact with a workpiece while being vibrated.