JPH04143074A - Welding arc starting method - Google Patents

Abstract

PURPOSE:To eliminate the generation of slag and to prevent a time loss by wire cutting by feeding a wire while vibrating a welding torch at the time of starting an arc and starting the arc by rubbing the wire tip on materials to be welded. CONSTITUTION:The loss at the tact time is reduced and vitreous slag 10 which is an insulator is rubbed mechanically on the materials 7 to be welded to remove the slag. In the case of a robot, an action to rub and remove the vitreous slag on the wire 2 tip, namely, a contact point of the materials to be welded is operated in a state with a starting signal turned ON and in a system where the welding torch 5 is vibrated. In addition, in the case of an automatic machine, a device for the torch vibration exclusive use is set up on the welding torch and the same constitution as in the case of the robot is formed by carrying out starting signal ON of the automatic machine and torch vibration ON at the same time. Consequently, since the time loss is not caused, a result of the 1.00% rate of success of arc starting can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arc starting method for arc welding using a consumable wire.

[Problems with the Prior Art] Conventionally, when arc welding is automatically performed using a consumable wire, there has been a phenomenon in which the wire and the workpiece are not energized at the time of arc start, causing arc start failure.

In such a case, in an unmanned line, it would cause the line to stop, causing a decrease in productivity.

First, the cause of this arc start failure will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a diagram of a welding method using consumable wire.

When the start signal is turned ON, the wire 2 wound around the reel 1 is transferred to the welding torch 5 by the feeding roller 3 and the pressure roller 4.
, are continuously fed to the workpiece 7 through the tip 6.

Welding current and voltage are supplied from a welding power source 8 through a welding torch 5 and from a tip 6 to the passing wire 2, and a welding arc 9 is generated between the tip of the wire and the workpiece 7.

FIG. 2 is a diagram for explaining the occurrence of arc start failure. When the wire 2 comes into contact with the workpiece 7, if a glassy slag 10 is generated at the tip of the wire, the slag becomes an insulator and the wire Therefore, the material to be welded cannot be energized and no arc is generated.

Accordingly, conventional methods for dealing with such problems include the following.

(1) Shape the tip of the wire to be sharp and flat before welding.

(2) Detects the slight arc of the pilot flame at the moment the wire touches the surface of the workpiece and applies a high-speed rising current to instantly grow the arc.

(3) Before welding, the wire is moved vertically by repeating forward and reverse rotation of the feed motor, and the tip of the wire is struck against the material to be welded to cause the slag to fall off.

Perhaps the above measures have been taken, but none of them lead to an arc start rate of 1oO%. In addition, method (1) requires a special tool, and method (2) does not perform a good arc start if there is slag. (3) lacks certainty.

Therefore, it was considered better to cut the tip of the wire with a special device after welding to keep it free of slag. However, if the tip of the wire is cut every time, the line takt will increase and the arc time rate will decrease for workpieces that require many arc starts within a cycle.

[Problems to be Solved by the Invention] An object of the present invention is to smoothly feed the wire while vibrating, mechanically remove the glassy slag that is a drawback of the conventional method, and achieve a successful arc start. rate 1.00%
The purpose is to provide an arc starting method that can perform the following steps.

[Means for Solving the Problems] The means of the present invention is to reduce the loss in takt time and to mechanically rub vitreous slag, which is an insulator, against the workpiece to be welded to remove the slag.

Normally, when automatic welding is performed using a robot's weaving function, the welding torch cannot vibrate unless an arc is generated. Further, if the welding torch is vibrated with the start signal OFF, the wire cannot be fed, so the wire escapes and the wire is drawn in, making it impossible to make contact with the workpiece.

Therefore, in order to deal with the above-mentioned problems, in the case of a robot, by using a system that allows the torch to vibrate while the start signal is ON, the glassy slag at the tip of the wire, that is, the point of contact with the material to be welded, can be scraped and removed. action can take place.

Furthermore, in the case of an automatic machine, a device dedicated to torch vibration is installed in the welding torch, and the activation signal of the automatic machine and the torch vibration are turned ON at the same time, thereby achieving a configuration similar to that of a robot.

[Embodiment] Fig. 3 shows an embodiment of the welding arc starting method according to the present invention.

In the figure, there are two modes on the left and right: vibrating while proceeding from the start position (right) and vibrating while stopping at the start position (left). , detect arc-on, or continue vibrating without detecting arc-on, and perform arc welding. When stopping at the start position and vibrating, arc-on is detected and the vibration is continued or stopped to perform arc welding.

[Effects of the Invention] According to the method of the present invention, the wire is vibrated and the tip of the wire is rubbed against the material to be welded to remove the generation of slag, and the arc can be started without causing time loss due to wire cutting. is possible, and the arc start success rate of about 98% with measures other than wire cutting can be improved to a 100% arc start success rate without any time loss.

[Brief explanation of the drawing]

Figure 1 is a system diagram showing a welding method using consumable wire, Figure 2
The figure is a cross-sectional view showing the state in which the wire contacts the tip and the workpiece at the time of arc start, and FIG. 3 is a view showing an embodiment of the present invention.

Claims (1)

[Claims] A welding arc starting method for welding using a consumable wire, which is characterized by feeding the wire while vibrating a welding torch when starting the arc, and starting the arc by rubbing the tip of the wire against the material to be welded.