JPH07204848A - Consumable electrode type arc welding controlling method and power unit therefor - Google Patents

Abstract

PURPOSE:To improve the steady property of welding state at the time of activating arc by providing plural numbers or periods for controlling the output of a welding power unit at the time of activating the arc. CONSTITUTION:In this consumable electrode system arc welding controlling method and power unit, the output of the power unit is made in a constant current characteristic between scores (ms) after activating arc, thereafter a voltage setting signal as the constant voltage characteristic is raised by a few (V) than the constant welding state between a few hundred (ms), the voltage setting signal is lowered by a few (V) than the constant welding state between the next few hundred (ms) and thereafter it is made into the setting voltage signal of the constant welding state.

Description

Detailed Description of the Invention

[0001]

The present invention relates to CO2 gas, Ar-C
When welding is performed by the consumable electrode type arc welding method using O2 mixed gas, the stability of the welding state at the time of starting the arc is improved by having a plurality of periods for controlling the output of the welding power supply device at the time of starting the arc. The present invention relates to a consumable electrode type arc welding control method and a welding power source device for achieving the purpose.

[0002]

2. Description of the Related Art It has been conventionally proposed to improve the stability of arc generation at the time of starting an arc by making the external characteristics of the welding power source device different from the steady state at the time of starting the arc.

1 (A) and 1 (B) show welding load voltage value Va [in the welding method (hereinafter referred to as short-circuit transfer welding)) in which welding is performed by repeating arc generation and short circuit generation in the prior art to perform droplet transfer. It is a waveform diagram which shows the waveform with respect to progress of time t of V] and welding current value Ia [A]. FIG. 3C is a transitional state diagram for explaining a state in which the droplet 1b growing on the wire tip 1a corresponding to them moves to the molten pool 2a on the workpiece 2. 1A to 1C,
Wire feeding speed 2.5 [m / min], wire type YG
W12 (JIS Z 3312), wire diameter 1.2
It is a figure when welding is carried out at an average welding current value of 100 [A] and an average welding load voltage value of 19 [V] by using [mm] and a shielding gas type CO2. Below, Figure 1
The operation of the conventional technique will be described with reference to (A) to (C).

(1) Time t0≤t in FIGS. 1 (A) to 1 (C)
<Explanation of t1 operation. After the welding start switch is turned on, the wire tip 1a approaches the workpiece 2 and a first small arc (hereinafter referred to as a pilot arc) is generated and a welding current flows. This welding current is detected at time t0. When the pilot arc is generated at the time of starting the arc, the external characteristic of the welding power source device becomes a constant current characteristic, and the welding current value Ia rises sharply. During the period of TS1 in which the welding current having the constant current characteristic is passed (hereinafter referred to as the constant current characteristic setting period), the welding current value Ia is
Unlike the constant voltage characteristic during normal welding, the start constant current value Ip shown in FIG.
Fixed to. Therefore, the droplet 1b formed on the tip 1a of the wire has a size capable of transferring to a short circuit, and the arc immediately after the start of welding is quickly stabilized. The time
The constant current characteristic setting period TS1 from t0 to t1 is equal to
It is preset to about [ms] or less.

(2) Time t ≧ t1 in FIGS. 1 (A) to 1 (C)
Description of Operation At time t1 when the constant current characteristic setting period TS1 shown in FIG. 1 (A) has elapsed after the generation of the pilot arc, the external characteristic is switched from the constant current characteristic to the constant voltage characteristic. At this time, since the welding current value Ia becomes small, the droplet 1b that has grown on the wire tip 1a moves to the molten pool 2a on the workpiece 2. After that, the arc and the short circuit are repeated due to the constant voltage characteristic, and the steady short-circuit transfer welding is performed.

FIG. 2 is a block diagram of an embodiment of a welding power supply device for achieving the arc starting method for short-circuit transfer welding of the prior art. 3A to 3D are comparison signal Ith and arc start determination signal Wc shown in FIG. 2 described later.
7 is a time chart showing the time course of r, the constant current setting signal Is, and the constant voltage characteristic steady voltage setting signal Vs3. WL in FIG. 2 is a welding load formed from the wire 1, the workpiece 2, the arc 3 or the short circuit. Power control circuit 10
Converts the commercial power supply PS into output characteristics suitable for the welding method. When the power control circuit 10 is, for example, an inverter-controlled power control circuit, the power control circuit 10 includes a primary rectifier circuit (not shown),
It includes an inverter circuit, an inverter transformer, a power conversion circuit such as a secondary rectification circuit, and a drive circuit thereof. The DC reactor DCL smoothes the output of the power control circuit 10,
Continuous energy is applied to the welding load WL. The output voltage detection circuit VB has an output voltage value Vc of the power control circuit 10.
That is, the output voltage value before being smoothed by the DC reactor DCL is detected and the output voltage detection signal Vb is output.

The welding current detection circuit CD has a welding current value Ia.
Is detected and the welding current detection signal Ic shown in FIG. 3 (A) is output to the arc start determination circuit WCR. The arc activation determination signal Wcr shown in FIG. 3 changes from a low level signal (hereinafter referred to as L) to a high level when the welding current detection signal Ic shown in FIG. 3 (A) exceeds a predetermined value of the comparison signal Ith. It replaces the signal (hereinafter referred to as H). The inverting circuit NT is
When the arc activation determination signal Wcr is L, the inverted signal Nt of H is output, and when the signal of the arc activation determination signal Wcr is H, the inverted signal Nt of L is output. For example, the monostable multi-1 circuit TM1 of the constant current period setting circuit is the inverted signal N.
Constant current characteristic setting period TS1 due to the decrease of t from H to L
During this period, the constant current period setting signal Tm1 of H is output.

When the constant current period setting signal Tm1 is in the H period, the constant current / constant voltage characteristic switching circuit SW1 has a contact b.
3 is connected to the constant current characteristic setting circuit CC.
The constant current setting signal Is as shown in (C) is output. The constant current comparison circuit CMI compares the constant current setting signal Is with the welding current detection signal Ic to obtain a constant current power control signal C.
A constant current characteristic for outputting mi to the power control circuit 10 is selected. Further, when the constant current period setting signal Tm1 becomes L again, the constant current / constant voltage characteristic switching circuit SW1 is connected to the contact a side, and the constant voltage characteristic steady voltage setting circuit CP3 to the one shown in FIG. Constant voltage characteristic Steady voltage setting signal Vs
3 is output. The constant voltage comparison circuit CMV compares the constant voltage characteristic steady voltage setting signal Vs3 with the output voltage detection signal Vb and outputs the constant voltage power control signal Cmv to the power control circuit 1.
A constant voltage characteristic for outputting to 0 is selected. Note that FIG.
, Sw1 is a constant current / constant voltage characteristic setting signal, which is a constant current power control signal Cmi or a constant voltage power control signal C
It is either mv.

As described above, in the prior art as well, the external characteristic of the constant current characteristic setting period TS1 is set to the constant current characteristic at the time of starting the arc so as to quickly stabilize the arc immediately after the start of welding.

[0020]

In the prior art, since the external characteristic at the time of arc starting is made a constant current characteristic and the welding current is steeply raised, unlike the constant voltage characteristic at the time of normal welding, the welding load WL Regardless of the size, the welding current is fixed to the constant start current value Ip, and the size of the droplet 1b formed on the wire tip 1a can be short-circuited to obtain a good arc start.

However, in the short-circuit transfer welding in the small current region where the welding current value Ia is 150 [A] or less, as shown in FIGS. 4 (A) to 4 (C), several tens [ms] after the arc is started.
Short circuits frequently occur in the range of several hundreds [ms]. Further, when it is between several hundreds [ms] and several [s], a short circuit hardly occurs, so that the arc period becomes longer or the arc is cut off. Hereinafter, the period in which the above-mentioned short circuit occurs frequently is referred to as a short circuit period excessively short period T2, and the period in which the arc period becomes long is referred to as a short circuit period excessively long period T3. The reason will be described with reference to FIGS. 4 (A) to 4 (C). Note that FIG.
The ratio of the scales on the time axis of (A) to (C) is shown in FIG.
To (C).

After the arc is started, the constant current characteristic setting period TS
During 1, the arc period continues due to the constant current characteristic, and the droplet 1b is formed on the wire tip 1a. When the constant current characteristic setting period TS1 ends and the short circuit period under-period T2 comes, the droplet 1b moves to the molten pool 2a, but when the welding current value Ia is low, the heat input is small, so the molten pool 2a expands. Instead, as shown by c3 in FIG. 4C, the molten metal is in a state of being deposited. In such a case, the arc length gradually becomes shorter and the cycle between the short circuit and the arc becomes shorter.

When the short-circuit cycle under-period T2 ends and the short-circuit cycle over-period T3 begins, the molten pool 2a grows to a sufficient size due to heat input from the arc, as indicated by c4 in FIG. 4 (c). Then, the molten metal that has migrated during the short circuit period T2 is diffused. Therefore, the arc period becomes long or the arc is broken, and the cycle of repeating the arc and the short circuit becomes irregular.

When short-circuit transfer welding is performed in a small current range of 150 [A] or less, the conventional technique has a constant current characteristic setting period TS1 in the control at the time of arc starting, despite the problems described above. Since only control was considered, it was not possible to prevent the irregularity of repeated arcs and short circuits.

[0030]

SUMMARY OF THE INVENTION The consumable electrode type arc welding control method and power supply device of the present invention have the above-mentioned problems.
In short-circuit transfer welding in the case of welding in a small current region of 50 [A] or less, the weld pool 2a having a sufficient size after the arc is started
A control method and a power supply device for improving an irregular repeating cycle of an arc and a short circuit that occurs until a gap is formed.

According to the consumable electrode type arc welding control method of claim 1, as shown in FIG. 5, several tens [ms] after the arc is started.
During, the welding current of constant current characteristic is output and the wire tip 1
The constant current characteristic setting period TS1 in which the droplet 1b formed in a is formed into a size that allows short-circuit transfer, and the following equation 1
During 00 [ms], a constant voltage characteristic high voltage setting period TS21 for expanding the arc length by outputting a welding current having a constant voltage characteristic whose output voltage value Vc is several [V] higher than the normal output voltage.
During the next several hundreds [ms], an arc is short-circuited by outputting a welding current having a constant voltage characteristic in which the output voltage value Vc is several [V] lower than the normal output voltage to shorten the arc length. Constant voltage characteristic low voltage setting period TS22 for regularly performing a repeating cycle with and a welding current having a constant voltage characteristic of a normal output voltage value in which the arc length does not become too short to output a cycle of arc and short circuit. This is a consumable electrode type arc welding control method in which a constant voltage characteristic steady voltage setting period TS2 that is regularly performed is set.

The consumable electrode type arc power supply device of claim 2 is
As shown in FIGS. 6 and 8, a constant current characteristic setting circuit CC that outputs a constant current setting signal Is for passing a welding current having a constant current characteristic, and an output voltage value Vc of several [V] rather than a normal output voltage. A constant voltage characteristic high voltage setting circuit CP1 which outputs a constant voltage characteristic high voltage setting signal Vs1 for passing a welding current having a high constant voltage characteristic, and an output voltage value Vc which is higher than a normal output voltage.
Is a few [V] constant voltage characteristic low voltage setting circuit CP2 which outputs a constant voltage characteristic low voltage setting signal Vs2 for passing a welding current having a low constant voltage characteristic, and a welding current having a constant voltage characteristic of a normal output voltage value Vc. Constant voltage characteristic steady voltage setting circuit CP3 that outputs a constant voltage characteristic steady voltage setting signal Vs3 to be energized
And the constant voltage setting high voltage setting signal Vs1 and the constant voltage setting low voltage setting signal V from the constant current setting signal Is after the arc is started.
A characteristic switching circuit S that outputs a constant voltage characteristic steady voltage setting signal Vs3 to the power control circuit 10 after switching to s2 sequentially.
It is a consumable electrode type arc power supply device provided with W.

The consumable electrode type arc power supply device of claim 3 is
A power supply device which embodies the consumable electrode type arc power supply device according to claim 2, wherein, as shown in FIG. 6, a constant current characteristic setting circuit for outputting a constant current setting signal Is for passing a welding current having a constant current characteristic. CC, a constant voltage characteristic high voltage setting circuit CP1 that outputs a constant voltage characteristic high voltage setting signal Vs1 that energizes a welding current having a constant voltage characteristic whose output voltage value Vc is several [V] higher than the normal output voltage, and Constant voltage characteristic low voltage setting circuit CP2 for outputting a constant voltage characteristic low voltage setting signal Vs2 for supplying a welding current having a constant voltage characteristic whose output voltage value Vc is several [V] lower than the output voltage, and a normal output voltage value. A constant voltage characteristic steady voltage setting circuit CP3 for outputting a constant voltage characteristic steady voltage setting signal Vs3 for passing a welding current having a constant voltage characteristic of Vc, and a constant current during a preset constant current characteristic setting period TS1 after arc start. A period setting signal Tm1 constant current period setting circuit TM1 outputs a constant voltage characteristic high voltage setting period previously set in after a constant current characteristic setting period TS1 TS2
1. A high voltage period setting circuit TM2 that outputs the high voltage period setting signal Tm2 to 1 and a preset constant voltage characteristic low voltage setting period TS2 after the elapse of the constant voltage characteristic high voltage setting period TS21.
2, a low voltage period setting circuit TM3 that outputs a low voltage period setting signal Tm3, and a constant voltage characteristic high voltage setting signal Vs from the constant current setting signal Is after the constant current characteristic setting period TS1.
The constant current / constant voltage characteristic switching circuit SW1 that switches to 1 and outputs to the power control circuit 10, and the constant voltage characteristic high voltage setting signal Vs1 to the constant voltage characteristic low voltage setting signal Vs2 after the elapse of the constant voltage characteristic high voltage setting period TS21. Constant voltage characteristic high voltage / low voltage switching circuit SW2 that is switched to and output to the power control circuit 10, and from the constant voltage characteristic low voltage setting signal Vs2 to the constant voltage characteristic steady voltage setting signal after the constant voltage characteristic low voltage setting period TS22 has elapsed. This is a consumable electrode type arc power supply device provided with a constant voltage characteristic low voltage / steady voltage switching circuit SW3 that switches to Vs3 and outputs to the power control circuit 10.

The consumable electrode type arc power supply device according to claim 4 is
A power supply device that embodies the consumable electrode type arc power supply device according to claim 2, and as shown in FIG. 8, a constant current characteristic setting circuit that outputs a constant current setting signal Is for passing a welding current having a constant current characteristic. CC, a constant voltage characteristic high voltage setting circuit CP1 that outputs a constant voltage characteristic high voltage setting signal Vs1 that energizes a welding current having a constant voltage characteristic whose output voltage value Vc is several [V] higher than the normal output voltage, and Constant voltage characteristic low voltage setting circuit CP2 for outputting a constant voltage characteristic low voltage setting signal Vs2 for supplying a welding current having a constant voltage characteristic whose output voltage value Vc is several [V] lower than the output voltage, and a normal output voltage value. A constant voltage characteristic steady voltage setting circuit CP3 for outputting a constant voltage characteristic steady voltage setting signal Vs3 for passing a welding current having a constant voltage characteristic of Vc, and a constant current during a preset constant current characteristic setting period TS1 after arc start. Constant current period setting circuit TM1 that outputs the period setting signal Tm1 and constant current / high voltage period setting that outputs the constant current / high voltage period setting signal Tm4 in a preset constant current / high voltage period TS23 after arc start A circuit TM4 and a constant current / high voltage / low voltage period setting circuit TM5 which outputs a constant current / high voltage / low voltage period setting signal Tm5 in a preset constant current / high voltage / low voltage period TS24 after the arc is started. And a constant current / constant voltage characteristic switching circuit SW1 for switching from the constant current setting signal Is to the constant voltage characteristic high voltage setting signal Vs1 and outputting to the power control circuit 10 after the constant current characteristic setting period TS1 elapses. After the voltage setting period TS23 has passed, the constant voltage characteristic high voltage setting signal Vs1
From the constant voltage characteristic low voltage setting signal Vs2 to the power control circuit 10 and outputting the constant voltage characteristic low voltage setting signal Vs2 to the power control circuit 10, and a constant current / high voltage / low voltage setting period TS2.
Consumable electrode type arc provided with a constant voltage characteristic low voltage / steady voltage switching circuit SW3 for switching from the constant voltage characteristic low voltage setting signal Vs2 to the constant voltage characteristic steady voltage setting signal Vs3 after 4 and outputting to the power control circuit 10. It is a power supply device.

[0040]

5 (A) and 5 (B) show the welding load voltage value Va [V] and the welding current value Ia [A] at the time of starting the arc in the control method of the consumable electrode type arc welding power supply device of the present invention.
5C is a waveform diagram showing a waveform with respect to the passage of time t, and FIG. 5C is a transitional state diagram for explaining a state in which the droplet 1b of the wire tip 1a corresponding thereto transitions. The operation will be described with reference to A) to (C).

(1) Time t0 ≦ t in FIGS. 5A to 5C
<Explanation of t1 operation. The description of the operation from time t0 to t1 is the same as the description of the operation of the constant current characteristic setting period TS1 from time t0 to t1 in FIGS. .

(2) Time t1≤t in FIGS. 5A to 5C
<Explanation of t2 operation. At time t1 when the constant current characteristic setting period TS1 shown in FIG. 5A has elapsed, the external characteristic is switched from the constant current characteristic to the constant voltage characteristic in which the output voltage value Vc is several [V] higher than the normal output voltage.

The output voltage value Vc in this period is set to be several [V] higher than the output voltage in the normal welding state to lengthen the arc length. By increasing the arc length, the molten pool surface is high because the molten pool 2a is not yet sufficiently large and the molten metal is deposited without being diffused only by the output voltage by the constant voltage characteristic steady voltage setting signal Vs3. Even when the arc length becomes short and the short-circuit and arc repetition cycle becomes short, the arc period is suitable for short-circuit transition as shown in FIG. Stabilize. The constant voltage characteristic high voltage setting period TS21 from time t1 to time t2 is set to about several hundreds [ms] in advance.

(3) Time t2 ≦ t in FIGS. 5A to 5C
<Explanation of t3 operation. At time t2 when the constant voltage characteristic high voltage setting period TS21 shown in FIG. 5A has elapsed, the external characteristic is changed from the constant voltage characteristic whose output voltage value Vc is several [V] higher than the normal output voltage to the normal external voltage. Switching to a constant voltage characteristic in which the output voltage value Vc is several [V] lower than the output voltage.

The output voltage value Vc in this period is set to be several [V] lower than the output voltage in the normal welding state to shorten the arc length. By shortening the arc length, the molten metal deposited due to the expansion of the molten pool 2a is diffused at the output voltage of the constant voltage characteristic high voltage setting signal Vs1, and the arc length is not shortened and the arc period is shortened. Even if it becomes long, the arc period is suitable for the short circuit transition as shown in FIG. 5 (A), and the repeating cycle of the arc and the short circuit becomes stable. The constant voltage characteristic low voltage setting period TS22 in the periods t2 to t3 is set to about several hundred [ms] in advance.

(4) Time t ≧ t3 in FIGS. 5A to 5C
Operation description. During the time t2 ≦ t <t3 described above, the output voltage value Vc is set lower than the output voltage in the normal welding state by several [V]. Therefore, if it is continued as it is, the arc length becomes too short and the arc length becomes too short. The repetition cycle of short circuit and short circuit will not be repeated regularly. Therefore, at time t3 when the constant voltage characteristic low voltage setting period TS22 shown in FIG. 5A has elapsed, the output voltage value Vc is switched to the output voltage value in the normal welding state.

When the output voltage value is switched to this normal welding state, since the size of the molten pool 2a is constant, as shown in FIG. 5 (C), a short-circuit transition arc period occurs, and the arc Since the repetition cycle of short circuit becomes regular, the welding result becomes uniform.

[0050]

First Embodiment (Explanation of FIG. 6 and FIG. 7) FIG. 6 is a block diagram of a first embodiment of a welding power supply device for carrying out the arc starting control method of the present invention. 7A to 7F show the comparison signal Ith, the arc start determination signal Wcr, the constant current setting signal Is, the constant voltage characteristic high voltage setting signal Vs1, the constant voltage characteristic low voltage setting signal Vs2 and the constant signal shown in FIG. Voltage characteristics Steady voltage setting signal V
It is a time chart which shows the time course of s3. Less than,
This will be described with reference to FIGS. 6 and 7. The circuit having the same reference numeral as that in FIG. 2 in FIG. 6 and the waveform diagram having the same reference numeral as in FIG. 3 in FIG.

In the high voltage period setting circuit, for example, the monostable multi-circuit TM2, when the constant current period setting signal Tm1 output from the constant current period setting circuit TM1 falls from H to L, H
The high voltage period setting signal Tm2 is output during the constant voltage characteristic high voltage setting period TS21. The constant voltage characteristic high voltage / low voltage switching circuit SW2 is connected to the contact b side while the high voltage period setting signal Tm2 output from the high voltage period setting circuit TM2 is H. The constant voltage comparison circuit CMV compares the constant voltage characteristic high voltage setting signal Vs1 output from the constant voltage characteristic high voltage setting circuit CP1 and the output voltage detection signal Vb shown in FIG. The characteristic is selected and the constant voltage power control signal Cmv is output to the power control circuit 10. When the high voltage period setting signal Tm2 output from the high voltage period setting circuit TM2 becomes L again, the constant voltage characteristic high voltage / low voltage switching circuit SW2 is connected to the contact a side. In FIG. 6, Sw2 is a high voltage / low voltage setting signal, which is either the constant voltage characteristic high voltage setting signal Vs1 described above or a low voltage / steady voltage setting signal Sw3 described later.

When the high voltage period setting signal Tm2 drops from H to L, the low voltage period setting circuit TM3 outputs the H low voltage period setting signal T during the constant voltage characteristic low voltage setting period TS22.
Output m3. The constant voltage characteristic low voltage / steady voltage switching circuit SW3 has a contact b while the low voltage period setting signal Tm3 is H.
Connected to the side. The constant voltage comparison circuit CMV includes a constant voltage characteristic low voltage setting signal Vs2 and an output voltage detection signal Vs output from the constant voltage characteristic low voltage setting circuit CP2 shown in FIG.
b is compared, the constant voltage low voltage characteristic is selected, and the constant voltage power control signal Cmv is output to the power control circuit 10.
When the high voltage period setting signal Tm2 becomes L again, the constant voltage characteristic low voltage / steady voltage switching circuit SW3 is connected to the contact a side. The constant voltage comparison circuit CMV compares the constant voltage characteristic steady voltage setting signal Vs3 shown in FIG. 7 (F) output from the constant voltage characteristic steady voltage setting circuit CP3 with the output voltage detection signal Vb to obtain a constant voltage steady voltage. The characteristic is selected and the constant voltage power control signal Cmv is output to the power control circuit 10. In FIG. 6, Sw3 is a low voltage / steady voltage setting signal, which is either the constant voltage characteristic low voltage setting signal Vs2 or the constant voltage characteristic steady voltage setting signal Vs3.

The constant current characteristic setting circuit CC outputs the constant current setting signal Is during the constant current characteristic setting period TS1. The constant voltage characteristic high voltage setting circuit CP1 keeps the constant voltage characteristic high voltage / low voltage switching circuit S during the constant voltage characteristic high voltage setting period TS21.
The constant voltage characteristic high voltage setting signal Vs1 is output to W2. The constant voltage characteristic low voltage setting circuit CP2 outputs the constant voltage characteristic low voltage setting signal Vs2 to the constant voltage characteristic low voltage / steady voltage switching circuit SW3 during the constant voltage characteristic low voltage setting period TS22. The constant voltage characteristic steady voltage setting circuit CP3 outputs a constant voltage characteristic steady voltage setting signal Vs3 during steady welding.

In the above embodiment, the constant current / constant voltage characteristic switching circuit SW1, the constant voltage characteristic high voltage / low voltage switching circuit SW2, and the constant voltage characteristic low voltage / steady voltage switching circuit SW3.
And 3 are constituted by three independent switching circuits, the constant current setting signal Is, the constant voltage characteristic high voltage setting signal Vs1 and the constant voltage characteristic low voltage setting signal Vs2 are sequentially arranged after the arc is started, as shown by the dotted line in FIG. Any other circuit may be used as long as it is a characteristic switching circuit SW that outputs the constant voltage characteristic steady voltage setting signal Vs3 to the power control circuit 10 after switching to.

[0070]

Second Embodiment (Explanation of FIG. 8 and FIG. 9) FIG. 8 is a block diagram of a second embodiment of a welding power supply device for carrying out the arc starting control method of the present invention. 9A to 9F show the comparison signal Ith, the arc activation determination signal Wcr, the constant current setting signal Is, the constant voltage characteristic high voltage setting signal Vs1, the constant voltage characteristic low voltage setting signal Vs2 and the constant signal shown in FIG. Voltage characteristics Steady voltage setting signal V
It is a time chart which shows the time course of s3. Less than,
This will be described with reference to FIGS. 8 and 9. The circuit in FIG. 8 having the same reference numeral as FIG. 6 and the waveform diagram in FIG. 9 having the same reference numeral as FIG.

The constant current / high voltage setting period TS23 includes a constant current characteristic setting period TS1 and a constant voltage characteristic high voltage setting period TS.
21 is the period added. The constant current / high voltage period setting circuit TM4 outputs the inverted signal Nt output from the inversion circuit NT.
When H drops from H to L, the constant current / high voltage setting period TS
During 23, the H constant current / high voltage period setting signal Tm4 is output. Constant voltage characteristic High voltage / low voltage switching circuit SW2
While the constant current / high voltage period setting signal Tm4 output from the constant current / high voltage period setting circuit TM4 is H, it is connected to the contact b side. The constant voltage comparison circuit CMV outputs the constant voltage characteristic high voltage setting circuit CP1 shown in FIG. 9D when the constant current / constant voltage characteristic switching circuit SW1 is switched from the contact b side to the contact a side. Voltage characteristics High voltage setting signal Vs1
And the output voltage detection signal Vb are compared, the constant voltage high voltage characteristic is selected, and the constant voltage power control signal Cmv is output to the power control circuit 10. Constant current / high voltage period setting circuit TM
When the constant current / high voltage period setting signal Tm4 output from the circuit 4 becomes L again, the constant voltage characteristic high voltage / low voltage switching circuit S
W2 is connected to the contact a side. In addition, in FIG.
Sw2 is a high voltage / low voltage setting signal, and is either the constant voltage characteristic high voltage setting signal Vs1 described above or a low voltage / steady voltage setting signal Sw3 described later.

Constant current / high voltage / low voltage setting period TS24
Is a period obtained by adding a constant current characteristic setting period TS1, a constant voltage characteristic high voltage setting period TS21, and a constant voltage characteristic low voltage setting period TS22. When the inversion signal Nt falls from H to L, the constant current / high voltage / low voltage period setting circuit TM5 holds the constant current / high voltage / low voltage period of H during the constant current / high voltage / low voltage setting period TS24. The setting signal Tm5 is output. Constant voltage characteristics Low voltage / steady voltage switching circuit SW3
While the high voltage / low voltage period setting signal Tm5 is H, it is connected to the contact b side. The constant voltage comparison circuit CMV is output from the constant voltage characteristic low voltage setting circuit CP2 shown in FIG. 9E when the constant voltage characteristic high voltage / low voltage switching circuit SW2 is switched from the contact b side to the contact a side. The constant voltage characteristic low voltage setting signal Vs2 is compared with the output voltage detection signal Vb to select the constant voltage low voltage characteristic, and the constant voltage power control signal Cmv is selected.
Is output to the power control circuit 10. When the constant current / high voltage / low voltage period setting signal Tm5 becomes L again, the constant voltage characteristic low voltage / steady voltage switching circuit SW3 is connected to the contact a side. At this time, the constant voltage comparison circuit CMV compares the constant voltage characteristic steady voltage setting signal Vs3 output from the constant voltage characteristic steady voltage setting circuit CP3 shown in FIG. Voltage steady-state voltage characteristic is selected,
The constant voltage power control signal Cmv is output to the power control circuit 10. In FIG. 8, Sw3 is a low voltage / steady voltage setting signal, which is either the constant voltage characteristic low voltage setting signal Vs2 or the constant voltage characteristic steady voltage setting signal Vs3.

The constant current characteristic setting circuit CC outputs the constant current setting signal Is during the constant current characteristic setting period TS1. The constant voltage characteristic high voltage setting circuit CP1 outputs the constant voltage characteristic high voltage setting signal Vs1 during the constant current / high voltage setting period TS23. The constant voltage characteristic low voltage setting circuit CP2 outputs the constant voltage characteristic low voltage setting signal Vs2 during the constant current / high voltage / low voltage setting period TS24. Constant voltage characteristic steady voltage setting circuit CP
3 outputs a constant voltage characteristic steady voltage setting signal Vs3.

[0100]

According to the first aspect of the present invention, in consumable electrode type arc welding in which a short circuit and an arc are repeatedly welded substantially periodically, as shown in FIG. Output welding current with constant current characteristics and wire tip 1a
The droplet 1b formed on
During the next several 100 [ms], a welding current having a constant voltage characteristic that is several [V] higher than the normal output voltage value is output to expand the arc length, and during the next several 100 [ms]. , The arc length is shortened by outputting a welding current having a constant voltage characteristic in which the output voltage value Vc is several [V] lower than the normal output voltage, and the arc length is shortened after the arc and short circuit are regularly repeated. This is a consumable electrode type arc welding control method in which a welding current having a constant voltage characteristic of a normal output voltage value that does not become too short is output to regularly perform a cycle of arc and short circuit. A second aspect of the present invention is a consumable-electrode-type welding power supply device that implements the welding control method of the first aspect, and a third aspect is a consumable-electrode-type arc welding device that further embodies the configuration of the second aspect. The effect equivalent to 1 can be achieved.

[Brief description of drawings]

1 (A) and 1 (B) are waveform diagrams showing waveforms of a welding load voltage value and a welding current value at the time of arc start of the prior art with respect to time, respectively, and FIG. 1 (C) is a diagram. ,
It is a transfer state diagram explaining the state which the droplet growing to the wire tip corresponding to them transfers to a molten pool.

FIG. 2 is a block diagram of an embodiment of a prior art welding power supply device.

3 (A) to 3 (D) are time charts showing a time course of a setting signal of an external characteristic of a welding power source, which is selected at the time of starting an arc in the prior art corresponding to each signal of FIG. 2. .

4 (A) and 4 (B) are waveform diagrams showing waveforms of a welding load voltage value and a welding current value at the time of arc start of the prior art with respect to time, respectively, and FIG. ,
It is a transfer state diagram explaining the state which the droplet growing to the wire tip corresponding to them transfers to a molten pool.

5 (A) and 5 (B) are waveform diagrams showing waveforms of a welding load voltage value and a welding current value at the time of arc starting of the present invention with time, and FIG. 5 (C). FIG. 4 is a transition state diagram for explaining a state in which droplets growing on the tip of the wire corresponding to them transition to a molten pool.

FIG. 6 is a block diagram of an embodiment of a welding power source device of the present invention.

7 (A) to (F) are time charts showing the time course of each signal shown in FIG. 6.

FIG. 8 is a block diagram of an embodiment of a welding power source device of the present invention.

9 (A) to 9 (F) are time charts showing the time course of each signal shown in FIG.

[Explanation of symbols]

 1 Wire 1a Wire tip 1b Droplet 2 Welding object 2a Molten pool 3 Arc 10 Power control circuit WL Welding load PS Commercial power source DCL DC reactor VB Output voltage detection circuit CD Welding current detection circuit WCR Arc start discrimination circuit NT inversion circuit CMI constant Current comparison circuit CMV constant voltage comparison circuit TM1 constant current period setting circuit TM2 high voltage period setting circuit TM3 low voltage period setting circuit TM4 constant current / high voltage period setting circuit TM5 constant current / high voltage / low voltage period setting circuit SW characteristic switching Circuit (SW1 to SW3) SW1 constant current / constant voltage characteristic switching circuit SW2 constant voltage characteristic high voltage / low voltage switching circuit SW3 constant voltage characteristic low voltage / steady voltage switching circuit CC constant current characteristic setting circuit CP1 constant voltage characteristic high voltage setting Circuit CP2 constant voltage characteristic low voltage setting circuit CP3 constant voltage characteristic steady current Setting circuit TS1 Constant current characteristic setting period TS2 Constant voltage characteristic steady voltage setting period TS21 Constant voltage characteristic high voltage setting period TS22 Constant voltage characteristic low voltage setting period TS23 Constant current / high voltage setting period TS24 Constant current / high voltage / low voltage setting Period Ia Welding current value Va Welding load voltage value Vc Output voltage value Ip Start constant current value Ic Welding current detection signal Vb Output voltage detection signal Cmi Constant current power control signal Cmv Constant voltage power control signal Is Constant current setting signal Vs1 Constant voltage characteristic High voltage setting signal Vs2 constant voltage characteristic low voltage setting signal Vs3 constant voltage characteristic steady voltage setting signal Ith comparison signal Wcr arc start discrimination signal Nt inversion signal Tm1 constant current period setting signal Tm2 high voltage period setting signal Tm3 low voltage period setting signal Tm4 Constant current / high voltage period setting signal Tm5 Constant current / high Pressure and low-voltage period setting signal Sw1 constant current-constant voltage characteristic setting signal Sw2 high voltage and low voltage setting signal Sw3 low voltage and steady state voltage setting signal T2 short period under-period T3 short period excessive period

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kozo Yamaguchi 2-11-1, Tagawa, Yodogawa-ku, Osaka

Claims (4)

[Claims] 1. A consumable electrode type arc welding control method for welding by repeating an arc and a short circuit in a substantially cyclic manner, wherein a welding current having a constant current characteristic is output for several tens of ms after the arc is started. During the constant current characteristic setting period in which the droplets formed at the tip of the wire are formed to a size that allows short-circuit transfer, and the following several 100 [ms], the output voltage value is several [ V] A constant voltage characteristic high voltage setting period in which a welding current having a high constant voltage characteristic is output to expand the arc length, and the output voltage value is several times higher than the normal output voltage during the next several hundred ms. [V] A constant voltage characteristic low voltage setting period in which a welding current having a low constant voltage characteristic is output to shorten the arc length so that a repeating cycle of an arc and a short circuit is regularly performed, and the arc length does not become too short. Dissolution of constant voltage characteristics of normal output voltage A consumable electrode type arc welding control method, which sets a constant voltage characteristic steady voltage setting period in which a contact current is output to regularly perform a cycle of arc and short circuit. 2. A consumable electrode type arc power supply device for repeating an arc and a short circuit in a substantially cyclic manner, and a constant current characteristic setting circuit for outputting a constant current setting signal for passing a welding current having a constant current characteristic, and a normal current characteristic setting circuit. Constant voltage characteristic high voltage setting circuit that outputs a constant voltage characteristic high voltage setting signal for passing a welding current having a constant voltage characteristic whose output voltage value is several [V] higher than the output voltage of the output voltage of the normal output voltage A constant voltage characteristic low voltage setting circuit that outputs a constant voltage characteristic low voltage setting signal for supplying a welding current having a constant voltage characteristic whose value is a few [V] low, and a constant voltage characteristic low voltage setting circuit for supplying a welding current having a constant voltage characteristic of a normal output voltage. A constant voltage characteristic steady voltage setting circuit that outputs a voltage characteristic steady voltage setting signal, and sequentially switches from the constant current setting signal to the constant voltage characteristic high voltage setting signal and the constant voltage characteristic low voltage setting signal after the arc is started. A consumable electrode type arc power supply device comprising a characteristic switching circuit for outputting the constant voltage characteristic steady voltage setting signal to the power control circuit after replacement. 3. A consumable electrode type arc power supply device for repeating an arc and a short circuit in a substantially cyclic manner, and a constant current characteristic setting circuit for outputting a constant current setting signal for passing a welding current having a constant current characteristic, and a normal current characteristic setting circuit. Constant voltage characteristic high voltage setting circuit that outputs a constant voltage characteristic high voltage setting signal for passing a welding current having a constant voltage characteristic whose output voltage value is several [V] higher than the output voltage of the output voltage of the normal output voltage A constant voltage characteristic low voltage setting circuit that outputs a constant voltage characteristic low voltage setting signal for supplying a welding current having a constant voltage characteristic whose value is a few [V] low, and a constant voltage characteristic low voltage setting circuit for supplying a welding current having a constant voltage characteristic of a normal output voltage. Constant voltage characteristic constant voltage setting circuit that outputs voltage characteristic constant voltage setting signal, constant current period setting circuit that outputs constant current period setting signal during preset constant current characteristic setting period after arc start, and constant current characteristic setting circuit. High-voltage period setting circuit that outputs a high-voltage period setting signal during a preset constant-voltage characteristic high-voltage setting period after the elapse of the constant-voltage setting period, and a preset constant voltage after the constant-voltage characteristic high-voltage setting period elapses. A low voltage period setting circuit that outputs a low voltage period setting signal during a characteristic low voltage setting period, and power control by switching from the constant current setting signal Is to the constant voltage characteristic high voltage setting signal after the constant current characteristic setting period has elapsed. A constant current / constant voltage characteristic switching circuit for outputting to the circuit, and switching to the constant voltage characteristic high voltage setting signal from the constant voltage characteristic high voltage setting signal after the lapse of the constant voltage characteristic high voltage setting period to the power control circuit. A constant voltage characteristic high voltage / low voltage switching circuit for outputting, and switching from the constant voltage characteristic low voltage setting signal to the constant voltage characteristic steady voltage setting signal after the constant voltage characteristic low voltage setting period has elapsed. Consumable electrode arc power supply and a constant voltage characteristic low voltage and steady state voltage switching circuit for output to the power control circuit. 4. A consumable electrode type arc power supply device for repeating an arc and a short circuit in a substantially cyclic manner for welding, and a constant current characteristic setting circuit for outputting a constant current setting signal for passing a welding current having a constant current characteristic; Constant voltage characteristic high voltage setting circuit that outputs a constant voltage characteristic high voltage setting signal for passing a welding current having a constant voltage characteristic whose output voltage value is several [V] higher than the output voltage of the output voltage of the normal output voltage A constant voltage characteristic low voltage setting circuit that outputs a constant voltage characteristic low voltage setting signal for supplying a welding current having a constant voltage characteristic whose value is a few [V] low, and a constant voltage characteristic low voltage setting circuit for supplying a welding current having a constant voltage characteristic of a normal output voltage. Constant voltage characteristic constant voltage setting circuit that outputs voltage characteristic constant voltage setting signal, constant current period setting circuit that outputs constant current period setting signal during preset constant current characteristic setting period after arc start, and after arc start The constant current / high voltage period setting signal that is output during the preset constant current / high voltage period of
High voltage period setting circuit and constant current / high voltage / low voltage period setting circuit that outputs constant current / high voltage / low voltage period setting signal during preset constant current / high voltage / low voltage setting period after arc start A constant current / constant voltage characteristic switching circuit that switches from the constant current setting signal to the constant voltage characteristic high voltage setting signal after the constant current characteristic setting period elapses and outputs the power control circuit; A constant voltage characteristic high voltage / low voltage switching circuit that switches from the constant voltage characteristic high voltage setting signal to the constant voltage characteristic low voltage setting signal after a lapse of a setting period and outputs the power control circuit, and the constant current / high voltage. A constant voltage characteristic low voltage / steady voltage switching circuit that switches from the constant voltage characteristic low voltage setting signal to the constant voltage characteristic steady voltage setting signal after the low voltage setting period has elapsed and outputs the constant voltage characteristic low voltage / steady voltage switching circuit to the power control circuit Worn electrode arc power supply.