JPS61229471A - Arc welding machine - Google Patents

Abstract

PURPOSE:To decrease the amt. of the spatters to be generated in the stage of the second arc generation by providing a short circuit detector to an arc welding machine and controlling a wire feed speed during the short circuit period. CONSTITUTION:The short circuit detector 11 discriminates whether the short circuit state or the arc state according to whether the arc voltage is above the specified value or not. A wire feed controller 12 breaks a wire 8 and adjusts the decrease of the wire feed speed when the signal of the short circuit stage is inputted thereto from the detector 11. The controller frees the wire 8 and feeds the wire 8 at the speed determined by a feed speed motor 14 in the case of the arc state. On the other hand, an output controller 13, when inputted with the signal for the short circuit state, outputs a control signal to an output control element 4 so as to decrease the welding output until the controller receives the next signal input for the arc state. The amt. of the spatters to be generated occurring in the magnitude of the arc current in the stage of the second arc generation is thus considerably decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a consumable electrode type arc welding machine that performs arc welding by automatically feeding a wire, which is a consumable electrode.

BACKGROUND OF THE INVENTION Conventionally, in consumable electrode type arc welding machines such as CO2/MAG welding, the wire feeding speed was kept at a constant speed determined by the set average welding current value.

When such a welding machine performs welding in the welding mode, the transfer of the molten wire mass to the welding base material is mainly performed by the separation force from the wire end due to the magnetic pinch force generated by the short-circuit current. , therefore requiring a large short circuit current.

Problems to be Solved by the Invention According to such conventional methods, the arc current at the moment when the short circuit is broken and the arc is ignited again becomes a large current equivalent to the short circuit current, so the arc force generates a large amount of spatter. was unavoidable.

An object of the present invention is to provide an arc welding machine that eliminates the above-mentioned conventional drawbacks.

Means for Solving the Problems In order to solve the above problems, the arc welding machine of the first invention includes a short circuit detector for determining whether or not the wire is short-circuited to the welding base material, and this short circuit detector. an output controller that receives an output signal from the short circuit detector and outputs a signal to a welding output control element to reduce the welding output during at least a short circuit period including the moment when the short circuit breaks and transitions to an arc; and a wire feed controller that reduces the wire feed speed during the short circuit period.

The second invention also provides a short circuit detector that determines whether or not the wire is connected to the welding base metal, and a short circuit period that includes at least the moment when the short circuit breaks and changes to an arc upon receiving an output signal from the short circuit detector. A configuration comprising: an output controller that outputs a signal for reducing intermediate welding output to a welding output control element; and a wire feed controller that receives an output signal from the short circuit detector and stops wire feeding during the short circuit period. That is.

The third invention also provides a short-circuit detector that determines whether or not the wire is short-circuited to the welding base metal, and a short-circuit period that includes at least the moment when the short-circuit breaks and changes to an arc upon receiving an output signal from the short-circuit detector. The structure includes an output Ill 1m device that outputs a signal to reduce the welding output during welding to a welding output control element, and a wire feed controller that receives the output signal of the short circuit detector and raises the wire during the short circuit period. It is something.

In other words, the present invention suppresses the short-circuit current in order to reduce the amount of spatter generated when a re-arc occurs. Therefore, in contrast to the conventional example in which the transfer of the molten wire mass to the welding base metal was mainly performed by magnetic pinch force caused by a large short-circuit current, the present invention reduces the wire feeding speed, stops the wire feeding, or By raising the
This produces an effect of increasing the detachment force of the molten mass from the wire end due to mechanical force, and allows the molten mass to be smoothly transferred with a small short circuit current. Such a reduction in the amount of spatter generated occurs due to the following effects. During the short circuit period, if the wire feeding speed is reduced, the wire feeding is stopped, or the wire is pulled up, the distance between the welding base metal and the wire in-phase plane becomes larger than in the conventional example. Therefore, the length of the molten lumps existing therebetween becomes longer, and the minimum diameter of the molten lumps becomes smaller accordingly. Therefore, the tensile stress and surface tension due to the weight of the molten lump below the position of the minimum diameter makes it easier to separate from the wire end. Therefore, the magnetic pinch force is small, and there is no need to increase the short circuit current. As a result of being able to reduce the short circuit current in this way, it is possible to significantly reduce the occurrence of spatter during re-arcing.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a configuration diagram of an arc welding machine according to an embodiment of the present invention, in which 1 is a welding power source input terminal, 2 is a main transformer, 3 is a rectifier, 4 is a welding output control element, 5 is a reactor, and 6 is an output terminal, 7 is a wire energizing tip, 8 is a wire, 9 is a welding base material, 10 is an arc, 11 is a short circuit detector, 12 is a wire feed controller, 13 is an output controller, 14 is a wire feed motor ,
15 is a power supply for the feeding motor, and 16 is a wire feeding cable.

The short circuit detector 11 determines whether there is a short circuit state or an arc state depending on whether the arc voltage is above a certain value. The wire feed v4 controller 12 has a mechanism for braking the wire 8, and brakes the wire 8 when receiving a short circuit signal input from the short circuit detector 11. The reduction value of the wire feeding speed can be adjusted by changing the strength of this braking. Further, when a signal indicating an arc state is received from the short circuit detector 11, the wire 8 is set free and the wire 8 is fed at a speed determined by a wire feed motor 14 at the rear which feeds the wire at a constant speed. Note that during braking, the wire length within the wire feed cable 16 increases, but this can be absorbed by making the inner diameter of the passage of the wire feed cable 16 2 to 5 times the wire diameter and allowing the wire 8 to slacken inside.

On the other hand, the output controller 13 detects a short circuit I! When a signal input indicating an unknowing state is received from 111, a control signal is output to the output control element 4 so as to reduce the welding output until the next signal input indicating an arc state is received. For example, if the welding output III control element 4 is a switching element such as a transistor, a control signal is output to shorten the on time.

Thus, by reducing the wire feeding speed during the short circuit period, the short circuit current can be reduced, resulting in
The amount of spatter generated due to the magnitude of the arc current when re-arf occurs can be significantly reduced.

FIG. 2 shows another embodiment, in which the output signal of the short circuit detector 11 is input, a signal is output after a set time from the start of the short circuit, and a signal indicating the arc state is input. A timer circuit 17 is provided which is reset by #Jill13, and the output signal of this timer circuit is output.
may be input as the input.

In the above embodiment, the wire feed controller 12 reduces the wire feed speed during the short circuit period, but the wire feed controller 12 can also stop the wire feed or change the wire 8. You may also try to pull it up.

Effects of the Invention As described above, according to the present invention, the short circuit current can be reduced by reducing the wire feeding speed, stopping the wire feeding, or pulling up the wire during the short circuit period. , it is possible to significantly reduce the amount of spatter generated due to the magnitude of the arc current when re-arfing occurs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an arc welding machine according to one embodiment of the present invention, and FIG. 2 is a circuit block diagram of essential parts of an arc welding machine according to another embodiment. 4... Welding output control element, 8... Wire, 9...
Welding base material, 11... Short circuit detector, 12... Wire feeder 11i11tIIl device, 13... Output controller

Claims (1)

[Claims] 1. A short-circuit detector that determines whether or not the wire is short-circuited to the welding base material, and a short-circuit that includes at least the moment when the short-circuit breaks and transitions to an arc upon receiving an output signal from the short-circuit detector. an output controller that outputs a signal to a welding output control element to reduce the welding output during the short circuit period, and a wire feed controller that receives the output signal of the short circuit detector and reduces the wire feed speed during the short circuit period. arc welding machine. 2. A short-circuit detector that determines whether or not the wire is short-circuited to the welding base metal, and upon receiving the output signal of this short-circuit detector, the welding output is reduced during the short-circuit period, which includes at least the moment when the short-circuit breaks and transitions to an arc. An arc welding machine comprising: an output controller that outputs a signal to a welding output control element; and a wire feed controller that receives an output signal from the short circuit detector and stops wire feeding during the short circuit period. 3. A short-circuit detector that determines whether or not the wire is short-circuited to the welding base metal, and upon receiving the output signal of this short-circuit detector, the welding output is reduced during the short-circuit period, which includes at least the moment when the short-circuit breaks and transitions to an arc. an output controller that outputs a signal to a welding output control element, and a wire feed controller that receives an output signal from the short circuit detector and pulls up the wire during the short circuit period.