JPH08215846A - Arc welding equipment - Google Patents

Abstract

PURPOSE: To prevent buckling of wire in cable conduit and at wire feed roller part by detecting the electric current of welding wire feed motor and stopping feed of wire in the case the detected electric current exceeds the allowable electric current. CONSTITUTION: A feed roller 5 is driven by a feed motor 7, a wire 2 is taken out from a wire reel 6 and feeded to a tip 12 at the tip of a torch 3 through a conduit cable 4, by generating arc between the tip and a base metal 1, welding is executed. At this time, the electric current of feed motor 7 is detected with an electric current detecting circuit 8, by comparing the detected electric current to the allowable electric current value set in an allowable electric current setting device 10 with a comparator 9, in the case the detected electric current value exceeds the allowable electric current value, it is discriminated as generation of tip deposition and then the feed motor 7 is controlled with a motor control circuit 11, the feed of wire 2 is instantly stopped. By this method, the buckling of wire 2 in the conduit cable 4 and at the feed roller 5 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc welding apparatus for preventing wire buckling or clogging in a conduit cable after tip welding in arc welding.

[0002]

_2. Description of the Related Art Conventionally, in CO ₂ / MAG welding / MIG welding, welding is performed by generating an arc between a wire and a base material via a tip for feeding a consumable wire as an electrode. Originally, during welding, the wire was surface-contact-powered almost at the tip of the tip to generate an arc, but with the arc time, wear progressed in the tip, resulting in point-contact power supply, causing a small discharge in the tip, and The wire is welded (hereinafter referred to as tip welding). Also, the spatter at the tip of the chip and the powder of the copper applied to the surface of the wire are melted and chip welding occurs. Further, the voltage with respect to the current rises for some reason and the wire burns up, resulting in chip welding. Similar to this phenomenon is wire welding, which is a phenomenon in which the wire plunges into the molten metal after welding is completed and the wire and base metal are welded. The detection method for this state is well known in the art. That is, after welding is completed, a voltage is applied between the wire and the base material, and the voltage drops if the wire is in a welded state. Therefore, the wire welded state is identified by detecting this voltage drop.

[0003]

However, in the conventional technique, the welding between the base material and the wire is detected and prevented.
The tip welding state could not be detected. Therefore, there is a problem that the wire is fed after the tip is welded and the wire buckles in the conduit cable.
In view of this, in Japanese Patent Laid-Open No. 62-166077, the welding between the welding wire and the contact tip is prevented by repeating the feeding and back feeding of the wire after a lapse of a certain time after the series of operations by the welding robot. That technology has been proposed. However, even with this proposal, the fear that chip welding may occur has not disappeared, and the problem that the wire is fed after the chip welding and the wire buckles in the conduit cable has not been solved. Therefore, an object of the present invention is to provide a device capable of detecting chip welding and preventing wire feeding after chip welding.

[0004]

In order to solve the above problems, the present invention relates to an arc welding apparatus, wherein the means for detecting the electric current of the welding wire feeding motor, the means for setting the permissible current, the permissible current and the above Means for comparing the detected currents,
The motor control means is provided for stopping the feeding of the wire when the detected current exceeds the allowable current.

[0005]

When the chip welding occurs, if the wire feeding is started, the wire cannot be fed due to the welding and the load increases. Then, the current of the welding wire feeding motor becomes higher than that in the normal time. If this current is detected and the allowable current value is exceeded, it is determined that tip welding has occurred, and the feeding of the welding wire is stopped instantaneously. Therefore, the buckling of the wire in the conduit cable and the buckling of the wire feeding roller portion can be prevented.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An arc welding apparatus will be described below as an embodiment of the present invention with reference to the drawings. FIG. 1 is a conceptual diagram for carrying out the present invention. During the welding operation, the feeding motor 5 drives the feeding roller 5, the wire 2 is fed from the wire reel 6 to the tip 12 of the torch 3 through the conduit cable 4, and an arc is generated between the base materials 1. . The feed motor 7 is under constant speed or constant torque control, and the motor current is detected by the current detection circuit 8. The detected current is compared with the allowable current value set by the allowable current setting unit 10 by the comparator 9, and the motor control circuit 11 controls the feed motor 7. When the tip 12 and the wire 2 are welded, a large torque is applied to the feeding motor 7 when the wire is fed. At that time, the detection current greatly increases. When the current is detected by the current detection circuit 8 and compared with the value set by the allowable current setting unit 10 by the comparator 9, the detected current exceeds the allowable current. As a result, the motor control circuit 11 stops the feed motor 7. At the same time, an alarm may be issued to the outside.

[0007]

As described above, according to the present invention, since the tip welding can be indirectly detected and the wire feeding can be stopped instantaneously, the wire buckling in the conduit cable,
It is possible to prevent buckling at the wire feeding roller portion.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Base Material 2 Wire 3 Torch 4 Conduit Cable 5 Feeding Roller 6 Wire Reel 7 Feeding Motor 8 Current Detection Circuit 9 Comparator 10 Allowable Current Setting Device 11 Motor Control Circuit 12 Chips

Claims (3)

[Claims] 1. In an arc welding apparatus, a means for detecting a current of a welding wire feeding motor, a means for setting a permissible current, a means for comparing the permissible current with the detected current, and the detected current being the permissible current. An arc welding apparatus comprising motor control means for stopping the feeding of the wire when a current is exceeded. 2. The arc welding apparatus according to claim 1, wherein an alarm is issued to the outside when the wire feeding is stopped. 3. The arc welding device is a welding robot, and the means for setting the permissible current and the means for comparing the permissible current and the detected current are provided in a robot control device for controlling the welding robot. The arc welding apparatus according to claim 1 or 2, which is characterized.