JPS61229468A - Power supply device for arc welding - Google Patents

Abstract

PURPOSE:To realize a uniform weld bead by providing circuits which output time count values with the arc generation stage and the short circuit stage respectively as a start point and controlling a welding current value by the peak current set signal of each circuit. CONSTITUTION:A short circuit detecting circuit 15 outputs the signal to the 1st and 2nd timer circuits 16, 17 and a peak current setting circuit 14 when the wire short circuit transfers to arc generation. The circuit 14 outputs the peak current set value to an output control circuit 13 at the input value of the 1st timer circuit 16 from the arc generation stage and the peak current set value to the control circuit 13 at the input value of the 2nd timer circuit 17 from the point of the timer when the arc generation transfers to the wire short circuit. The output control circuit 13 compares the signal from the circuit 14 and the signal from a welding current detecting circuit 12 and outputs a command signal to a welding output control element 4 so as to stop the welding output when the welding current is larger and to supply the welding output when the welding current value is smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an arc welding power supply device for automatically feeding a welding wire, which is a consumable electrode, to perform arc welding.

Conventional technology When controlling the output of an arc welding power source that automatically feeds welding wire to perform welding, the output control element controls the output depending on the amount of wire fed or changes in the input power supply voltage. On the other hand, it has been used to keep the welding voltage constant.

Furthermore, even with a configuration in which the welding current value is detected and feedback-controlled to suppress the welding current rise speed when the wire approaches the workpiece, the welding current value is adjusted only when the wire is short-circuited. Ta.

Problems to be Solved by the Invention According to the above-mentioned prior art, the opening at the time of arc occurrence is
llwJ was not possible, and the time opening from arc initiation to the next wire short circuit had to depend on the self-regulating action of the welding arc. Therefore, it is not possible to control the size of the molten ball at the tip of the wire that grows during one arc generation, and this can cause large spatter or the wire to get caught in the next short circuit, making it difficult to weld smoothly. It was a loss. Therefore, even if the wire feeding speed changes instantaneously, 1
A conventional problem was that the amount of molten metal transferred from the wire to the workpiece could not be maintained uniformly due to the wire being short-circuited. Furthermore, even when a wire is short-circuited, the short-circuit current increases from time to time due to the constant voltage characteristics of the main welding transformer, and this is the cause of spatter when a re-arc occurs.

Means for Solving the Problems In order to solve the above conventional problems, the arc welding power supply device of the present invention determines whether the welding wire is short-circuited by contact with the workpiece or whether an arc is generated. a wire short-circuit detection circuit that outputs a signal, and a first circuit that receives the output signal of this wire short-circuit detection circuit and outputs a WIIlill count value starting from when the wire short circuit is released and an arc occurs.
a second timer circuit that receives the output signal of the wire short-circuit detection circuit as an input and outputs a time count value starting from the time when the wire short-circuits from the state of arc generation; and the output signal of the wire short-circuit detection circuit; The time count value output of the first timer circuit and the time count value output of the second timer circuit are input, and during arcing, a peak current setting signal is set in advance for the time count value of the first timer circuit. and a peak current setting circuit that outputs a preset peak current Fi & setting signal for the time count value of the second timer circuit when the wire is short-circuited, and the output signal of this peak current setting circuit and the welding current value. Ill III to the welding output control element so that the welding current value becomes the peak current setting value by inputting the output signal of the welding current value detection circuit that detects the peak current value.
The configuration includes an output control circuit that outputs a signal.

action According to the above configuration, the welding current can be controlled arbitrarily.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1WA to 3.

FIG. 1 is a configuration diagram of a welding device equipped with an arc welding power source according to an embodiment of the present invention, in which 1 is a welding power source input terminal, 2 is a welding main transformer, 3 is a rectifier, and 4 is a welding output control element. ,
5 is a welding reactor, 6 is a shunt, 7 is a welding power source output terminal, 8 is a contact tip for energizing, 9 is a welding wire,
10 is a workpiece to be welded, 11 is a welding arc, 12 is a welding current value detection circuit, 13 is an output control circuit, 14 is a peak current setting circuit, 15 is a wire short circuit detection circuit, 16 is a first timer circuit, and 17 is a first timer circuit. This is the second timer circuit. The wire short circuit detection circuit 15c outputs a signal for determining whether the welding wire 9 is in contact with the object 1GIC or an arc is generated.The first timer circuit 16 is a wire short circuit detection circuit. The second timer circuit 17 inputs the output signal of the wire short circuit 15 and outputs a time count value starting from the time when the wire short circuit is released and an arc occurs. The peak current setting circuit 14 outputs a time count value starting from the time when the wire is short-circuited.The peak current setting circuit 14 includes a wire short-circuit detection circuit 15 and first and second timer circuits 16.1.
When an arc occurs, a preset peak current setting signal is input to the time count value of the first timer circuit 17, and when a wire short circuit occurs, a preset peak current setting signal is input to the output signal of the second timer circuit 17. Outputs a preset peak current setting value for the count value. The output l1l1111 circuit 13 is
The output signal of the peak current setting circuit 14 and the output signal of the welding current value detection circuit 12 for detecting the welding current value are input,
A control signal is output to the welding output control element 4 so that the welding current value becomes the peak current setting value. Further, the peak current setting circuit 14 and the first and second timer circuits 16 and 17 are configured by a microcomputer, and the time is generated and counted within the first and second timer circuits 16 and 17. The welding phenomenon is sufficiently controlled as
The frequency was set to 4Kl-12, which is the resolution that can be achieved. This allows the peak current setting value to be arbitrarily set every 250 μsec. Of course, this clock frequency can also be arbitrarily selected.

Hereinafter, the effects of the above configuration will be explained.

Suppose now that the wire short circuit is removed and an arc occurs.

This signal is a wire short circuit detection circuit 1 that detects the output voltage and outputs a signal that identifies the voltage value as high or low level depending on whether the voltage value is below a certain value or above a certain value.
5 to the first and second timer circuits 16, 17 and the peak current setting circuit 14. The first timer circuit 16 clears its count when the wire short circuit changes to arc occurrence, counts the number of internally generated clock pulses, and increases the time count value.

Similarly, the second timer circuit 17 clears its count value when the occurrence of an arc changes to a wire short circuit, counts the number of internally generated clock pulses, and increases the time count value. The peak current setting circuit 14 has a built-in memory element in which the peak current setting value for the address is preset and stored, and the input of the first timer circuit 16 is started from the time when the transition from wire control to arc generation occurs. The peak current setting value stored in advance in that address is outputted to the output i control circuit 13 using the value as an address, and similarly, the input value of the second timer circuit is used as the address from the time when the transition from arc occurrence to wire short circuit occurs. The peak current setting value stored in advance in that address is output to the output control circuit 13. Of course, the peak current setting circuit 1 is designed to output the peak current setting value from the address area that differs when an arc occurs or when a wire short circuit occurs.
4 is selected based on the signal from the wire short circuit detection circuit 15. The output control circuit 13 compares the signal from the peak current setting circuit 14 with the signal from the welding current value detection port [112], and stops the welding output when the welding current value is high, and stops the welding output when the welding current value is low. If there is, a command signal is output to the welding output control element 4 to supply the welding output.

Fig. 2 shows an example of the arrangement of peak current setting values that are input in advance into the memory element in the peak current setting circuit 14, and shows an example of the arrangement of peak current setting values that are input in advance into the memory element in the peak current setting circuit 14. Outputs the peak current setting value of 600 A stored at address 1. ...n
The peak current setting values within −1, n, and n+1 are sequentially output. From the moment when arc generation shifts to wire control, the peak current setting value is set according to the count value of the second timer circuit 11 within the area of the wire short circuit, regardless of the count value of the first timer circuit 16 up to that point. Output. The output according to the peak current setting value in the storage element shown in FIG. 2 is shown in FIG. 3a. By suddenly reducing the peak current value at time n as shown in Fig. 3a, the distance (arc length) between the wire tip and the workpiece 10 is rapidly reduced as shown in Fig. 3, and the next wire short circuit occurs. can be controlled so that the amount of molten metal does not exceed a certain value. As a result, the next time the wire is short-circuited, even if the peak current is set to a low value, the problem of wire sticking will not occur, and the next arc can be generated with less spatter. In other words, the amount of metal transferred from the welding wire 9 to the workpiece 10 at the time of each wire short circuit can be made uniform.

Note that FIG. 2 is an example of implementation, and instead of using the data bank system of data for addresses as shown in FIG. 2, it is also possible to have a configuration in which a peak current setting value is output by a program according to a count value, for example.

Effects of the Invention As described above, according to the present invention, the welding current waveform can be arbitrarily controlled and the arc generation time can be kept within a certain value. As a result, the amount of metal transferred from the welding wire to the workpiece during one wire short circuit can be made uniform, and a uniform welding speed can be achieved. Furthermore, since the amount of transferred metal is uniform, the peak current value when the wire is short-circuited does not need to be set to an unnecessarily high value, and spatter scattering can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a welding device equipped with an arc welding power supply device according to an embodiment of the present invention, and Fig. 2 is an explanation of the data array in the memory element for peak current setting in the arc welding power supply device. FIG. 3A is an explanatory diagram of the time course of the distance between the wire tip and the object to be welded, and the same figure is an explanatory diagram of the temporal change of the peak current set value output. 4... Welding output control element section, 5... Welding reactor, 6... Shunt switch, 7... Welding power source output terminal, 8...
・Electrification contact tip, 9...Welding wire, 1
0... - object to be welded, 11... welding arc, 12...
Welding current value detection circuit, 13... Output control circuit, 14.
...Peak electric current setting circuit, 15...Wire yB rating detection circuit, 16...First timer circuit, 17...Second timer circuit

Claims (1)

[Claims] 1. A wire short circuit detection circuit that outputs a signal to determine whether the welding wire is short-circuited by contact with the workpiece or an arc is generated, and the wire short circuit is canceled by inputting the output signal of this wire short circuit detection circuit. a first timer circuit that outputs a time count value starting from the time when an arc occurs, and a second timer circuit that receives the output signal of the wire short circuit detection circuit as an input and outputs a time count value starting from the time when the wire short-circuits from the state where the arc occurs. 2 timer circuit, and the first timer circuit receives the output signal of the wire short circuit detection circuit, the time count value output of the first timer circuit, and the time count value output of the second timer circuit as inputs. a peak current setting circuit that outputs a preset peak current setting signal for the time count value of the second timer circuit, and outputs a preset peak current setting signal for the time count value of the second timer circuit when the wire is short-circuited; and an output control circuit that receives the output signal of the welding current value and the output signal of the welding current value detection circuit that detects the welding current value and outputs a control signal to the welding output control element so that the welding current value becomes the peak current setting value. Equipped with a power supply device for arc welding.