JP3002749B2 - Pulse arc welding method and pulse arc welding apparatus using this method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pulse arc welding method and an improvement of a pulse arc welding apparatus using the method.

[Prior art] In this type of pulse arc welding, a peak current Ip and a base current Ib necessary for the transfer of droplets are alternately applied to the welding wire, and the welding current is melted by the pinch effect by applying the peak current Ip. Welding is performed by dropping, but since there are many factors to be set, generally, welding average current Ia (wire feeding speed), peak current Ip
In general, the arc voltage control is performed so that the welding average voltage Ea becomes a specified level by setting the energization period tp, the base current Ib, and the welding average voltage Ea and variably controlling the energization cycle T. (Since the peak current energizing period tp is set, variably controlling the energizing cycle T corresponds to variably controlling the base current energizing period tb).

By the way, conventionally, such a base current conduction period
As a configuration for controlling tb (energization cycle T), the detected welding voltage is compared with a welding average voltage reference value to determine an error signal, and the obtained error signal is converted to a voltage / frequency conversion circuit (V / F conversion circuit). In addition to the above, a negative feedback control method is adopted in which the base current Ib is switched to the conduction of the peak current Ip at every cycle T according to the error signal level, and thereby the base current conduction period tb is variably controlled.

However, in a control system using such a negative feedback control method, a time delay occurs in the control, so that the control system cannot follow a transient fluctuation in welding voltage, and a time constant that lingers in the control system. There are problems such as instability of control depending on factors, and hunting may be sustained in severe cases, and in reality, accurate arc voltage control cannot be expected.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and eliminates a time delay of control in a control system during a base current energizing period and an unstable element of the control system to reduce a transient welding voltage. It is an object of the present invention to provide a pulse arc welding method capable of stably automatically controlling a welding average voltage to a predetermined value even with fluctuations.

Another object of the present invention, which is proposed at the same time, is to provide a welding apparatus for realizing the above welding method.

[Means for Solving the Problems] According to the method of the present invention according to claim 1 proposed to achieve the above object, the average welding voltage is controlled while controlling the peak current conduction period to a predetermined value set in advance. In order to control the base current energization period so as to match the welding average voltage reference value, the detected welding voltage is compared with a predetermined welding average voltage reference value from the start of the peak current energization, and integration of the difference is started. Then, when the integrated output level coincides with the integrated output level at the start of the integration when the base current is continuously supplied, the supply of the base current is stopped to switch to the supply of the peak current.

According to a second aspect of the present invention, there is provided a peak period control unit for controlling a peak current period to a predetermined value, and a base current period such that a welding average voltage coincides with a welding average voltage reference value. In order to control, the welding voltage detected from the start of the peak current energization is compared with a predetermined welding average voltage reference value, and the integration of the difference is started. A welding voltage error integrating circuit that compares the detected welding voltage with the welding average voltage reference value and integrates the difference, and an integrated output level of the welding voltage error integrating circuit coincides with the integrated output level at the start of the integration. And a voltage integration level discriminator for outputting a base current energization end signal to the peak period control means and switching to the peak current energization. It has a configuration that includes a stage.

As an example of such a base period control means in the present invention, in a welding voltage error integration circuit, a welding voltage detected from the start of the peak current application to the base current application is compared with a welding average voltage reference value, and the difference is obtained. Can be integrated from the zero level, and when the integrated output level returns to the zero level again, the voltage integration level determination unit including the zero-crossing detection circuit determines and outputs a peak current energization start signal.

[Operation] According to the first aspect of the present invention, the welding voltage detected from the start of the peak current energization is compared with a predetermined welding average voltage reference value while controlling the peak current energization period to a preset value. Then, when the integration of the difference is started, and when the integrated output level coincides with the integrated output level at the start of the integration at the time of the subsequent base current supply, the base current supply is stopped and switched to the peak current supply. The base current conduction period is automatically controlled such that the welding average voltage matches the welding average voltage reference value. As a result,
The peak current and the base current are alternately switched and energized to perform welding.

According to the second aspect of the present invention, the peak period control means outputs the peak current conduction signal for a predetermined time each time the base current conduction end signal output from the base period control means is received. In the base period control means, the welding voltage error integrating circuit compares the welding voltage (instantaneous value of the peak voltage) detected from the start of the peak current application with a predetermined welding average voltage reference value. To start integrating the difference
Similarly, when the base current is continuously supplied, the detected welding voltage (the instantaneous value of the base voltage) is compared with the welding average voltage reference value to integrate the difference, and the integrated output level is the integrated output at the start of the integration. When the level coincides with the level, the voltage integration level discriminator discriminates and outputs a base current energization end signal to the peak period control means to switch to the energization of the peak current, whereby the welding average voltage matches the welding average voltage reference value. The base current conduction period is controlled as described above.
As a result, the peak current and the base current are alternately switched and energized, and welding is performed.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of a configuration of a main part of a welding apparatus for carrying out the pulse arc welding method according to the present invention described in claim 1.

The gist of the present invention is that the peak current Ip and its energizing period t
p, welding average current Ia, base current Ib, and welding average voltage E
If each reference value of a is set manually, the base current conduction period is set so that the welding average voltage Ea matches the welding average voltage reference value Er.
tb is automatically controlled.

In the figure, 1 is a base period control means for automatically controlling the base current conduction period tb, and 2 is a peak current conduction period.
A peak period control unit 3 for controlling tp to a manually set value is a welding voltage setting unit 3 for manually setting the welding average voltage reference value Er. It should be noted that in the figure, a current control means (to be described later) for controlling the supply of the welding current in accordance with the peak current supply signal or the base current supply signal output from the peak period control means 2 is omitted. Peak current Ip or base current Ib
Negative feedback control is performed so that the current is supplied stably.

The base period control means 1 controls the welding voltage E (peak voltage) between the welding wire and the welding base metal from the start of the peak current supply.
The instantaneous value of Ep) is compared with the welding average voltage reference value Er set by the welding voltage setting unit 3 and integration of the difference signal is started,
Similarly, when the base current is applied, the welding voltage E
A welding voltage error integration circuit 10 for comparing the instantaneous value of the (base voltage Eb) with the welding average voltage reference value Er and integrating the difference signal
A voltage integration level discriminator 11 that outputs a base current energization end signal when the integrated output level of the welding voltage error integration circuit 10 matches the integration output level at the start of integration at the start of peak current energization. .

In this configuration, the welding voltage error integration circuit 10 starts the integration of the difference signal from the state where the integrated output level is zero level from the start of the peak current application to the base current application, and the integrated output level is again increased. When the voltage reaches a zero level (below), the voltage integration level determination unit 11 (hereinafter, referred to as a zero-cross detection circuit) comprising a zero-cross detection circuit determines and outputs a base current energization end signal.

That is, in the base period control means 1, the peak voltage Ep and the welding average voltage reference value Er in the peak current conduction period tp are determined.
When the integrated level of the difference between the base current and the welding average voltage reference value Er in the base current energizing period tb coincides with the integrated level of the difference, the base current Ib is stopped and the peak current Ip is turned on. Since the switching operation is performed, the base current energization period tb is controlled so that the welding average voltage Ea completely matches the welding average voltage reference value Er.In addition, since it is not a negative feedback control system, control time delay and hunting Is not generated.

On the other hand, each time the base period control unit 2 receives the base current conduction end signal output from the base period control unit 1, the peak period control unit 2 outputs a peak current conduction signal for a predetermined time tp. An operation of switching to the energization signal is performed.

The welding method of the present invention implemented by such a configuration will be described with reference to the waveform diagrams of FIGS. 2 (a) to 2 (f).
Incidentally, the corresponding portions in FIG. 1 correspond to (b) to (f).
(The welding current is not shown in FIG. 1, so that the symbol (a) is not shown).

The average welding current Ia (welding wire feeding speed), the peak current Ip, the peak current conduction period tp, the base current Ib, and the average welding voltage Ea are set according to the welding conditions.

When a base current supply end signal is output from the base period control means 1, the peak period control means 2 outputs a peak current supply signal for a predetermined period of time tp after receiving the base current supply end signal. And after this,
A base current energization signal is output.

As described above, in the peak period control means 2, every time the base current supply end signal is received from the base period control means 1,
The operation of outputting the peak current energization signal for a predetermined time tp is repeated.

 On the other hand, the base period control means 1 performs the following operation.

When a peak current supply signal is output from the peak period control means 2 in response to the base current supply end signal output from the base period control means 1, the welding voltage error integration circuit 10 causes the detected welding voltage E (the peak voltage Ep of the peak voltage Ep) to be detected. (Instantaneous value) is compared with the welding average voltage reference value Er set by the welding voltage setting unit 3 to start integrating the difference signal.

When the peak current energization signal output from the peak period control means 2 stops and the base current energization signal is subsequently output, the welding voltage error integration circuit 10 detects the detected welding voltage E (the instantaneous value of the base voltage Eb). ) Is compared with the welding average voltage reference value Er set by the welding voltage setting unit 3 to integrate the difference signal.

On the other hand, the zero-cross detection circuit 11 monitors the integrated output level of the welding voltage error integration circuit 10, and when the integrated output level of the difference signal from the start of the peak current application to the base current application becomes zero level (below), the peak period. A base current energization end signal is output to the control means 2, and the peak current energization signal is output by the peak period control means 2 to return to the operation again. The base period control means 1 outputs a base current energization end signal by repeating the above operations (1) to (4).

That is, in the base period control means 1, the base current Ib
The peak period control means 2 outputs a peak current conduction signal for a predetermined time in response to the base current conduction end signal output from the base period control means 1, Base current Ib
And the peak current Ip are alternately energized.

3 (a) to 3 (c) show waveforms for explaining the operation principle of the base period control means 1, which is also a point of the present invention.

In the welding voltage error integration circuit 10, the peak current conduction period tp
Of the peak voltage Ep and the welding average voltage reference value Er (Ep−Er) from the zero level (corresponding to the hatched portion α in FIG. 3 (b)) from the start of the operation, and integrating with a slope corresponding to the difference. The output level rises, and when the base current is subsequently supplied, the difference (Eb−Er) between the base voltage Eb and the welding average voltage reference value Er is integrated (corresponding to the hatched portion β in FIG. 3 (b)) to obtain the difference. The integrated output level falls with a corresponding slope. Then, when the integrated output level becomes zero level (α = β), the base current Ib
Has been turned off.

Therefore, according to this control, for example, the welding average voltage Ea is set to be low, and a short circuit occurs at the time of droplet detachment during the base current energizing period tb (see FIG. 3 (b)), and the welding voltage sharply decreases. In such a case, the welding voltage error integration circuit
The control is performed so that the fall of the integral output of 10 becomes steep according to the difference, the base current energizing period tb is automatically reduced to tb1, and the welding average voltage Ea matches the welding average voltage reference value Er ( (See α ′ = β ′ in FIG. 3 (b)). Also,
Even if the arc length transiently increases due to hand shake during welding and the base voltage Eb increases to Eb1, the decrease in the integral output of the welding voltage error integration circuit 10 is the difference (Eb1−E
r), the base current conduction period is automatically increased to tb2, and control is performed to match the welding average voltage Ea to the welding average voltage reference value Er (α ″ in FIG. 3 (b)). = Β ″). Furthermore, even when the welding voltage E (peak voltage Ep and base voltage Eb) fluctuates due to transient fluctuations in welding conditions other than these, the average welding voltage Ea
Is controlled to completely match the welding average voltage reference value Er.

As described above, according to the present invention, even when the welding voltage fluctuates due to any factor, the welding average voltage is set for each energizing cycle including the peak current energizing period tp and the base current energizing period tb.
Since the base current conduction period tb is controlled in real time so that Ea completely matches the welding average voltage reference value Er,
The stability of the average welding voltage can be remarkably improved even for transient phenomena, and problems such as control time delay and hunting that occur in a negative feedback control system or the like are eliminated.

FIG. 4 is a block diagram showing an example of the configuration of a pulse arc welding apparatus for implementing the above-described pulse arc welding method of the present invention (corresponding to claim 2).

In the figure, 1 is a base period control unit, 2 is a peak period control unit, 3 is a welding voltage setting unit, and these are the first unit.
Since they are the same as those in the figure, the same reference numerals are given. Reference numeral 4 denotes current control means for outputting an energization control signal for energizing by switching between the peak current Ip and the base current Ib in accordance with the peak current energization signal or the base current energization signal output from the peak period control means 2; An activation control unit that outputs a compensation signal for prompting the generation and extension of an arc when the device is activated. AMP1 is a welding current amplifying circuit for amplifying the welding current, AMP2 is a welding voltage amplifying circuit for amplifying the welding voltage (in this embodiment, the amplification degree is set to less than 1), and 6 is output from the current control means 4. A pulse width control unit 7 controls the duty of the switching voltage output from the inverter INV in accordance with the energization control signal. Reference numeral 7 denotes a wire feed control unit that controls the feed of the welding wire W. REC is a rectifier circuit for rectifying the three-phase AC voltage, T is a transformer for insulatingly transforming the switching voltage output from the inverter INV,
D1 and D2 are diodes for full-wave rectification of the power output from the transformer T, S is a shunt resistor for extracting the welding current level as a corresponding voltage level, L is a reactor,
M indicates a welding base material.

In the base period control means 1, the welding voltage error integrating circuit 10 and the voltage integration level discriminating section 11 comprising a zero-cross detecting circuit are the same as those in FIG. The analog switch SW10 is opened until the arc is generated, and prohibits the no-load voltage amplified by the welding voltage amplification circuit AMP2 from being applied to the welding voltage error integration circuit 10, whereby the arc is generated. Prevents the output timing of the base current energization end signal output from the zero-crossing detection circuit 11 from being delayed by the no-load voltage (higher than the welding voltage after the occurrence of an arc) until the start, and controls the base current energization period tb to the minimum. (As described below
(controlled by tm).

The current control means 4 includes a welding current setting unit 40 for setting a welding average current reference value Ir, a peak current setting unit 41 for setting a peak current reference value Ipr, and a base current setting unit 42 for setting a base current reference value Ibr. Analog switches SW40 and SW41 for selecting and switching the reference level set by each of these setting units according to the peak current energization signal or the base current energization signal output from the peak period control means 2, and the peak current reference value Ipr or A welding current error amplifier 43 is provided which outputs an error signal between the base current reference value Ibr and the welding current I output from the welding current amplifier AMP1. still,
The peak current setting unit 41 is configured to operate in conjunction with the welding current setting unit 40, so that even when the peak current reference value Ipr is set to the minimum, the peak current reference value Ipr does not become lower than the welding average current reference value Ir. ing. The welding average current reference value Ir set by the welding current setting unit 40 is
And the welding wire is fed at a speed proportional to the welding average current reference value Ir.

The pulse width control unit 6 generates a pulse width control signal corresponding to the error signal transmitted from the current control unit 4 by the PWM control circuit 61 and transmits the pulse width control signal to the inverter INV through the drive circuit 60 to change the duty of the switching voltage. , Thereby the welding current I (peak current Ip and base current Ib)
Is always controlled so as to be equal to the set level of the current control means 4.

The activation control unit 5 opens the analog switch SW10 of the base period control unit 1 until the arc is generated, while the welding control of the current control unit 4 is continued until a predetermined time t1 has elapsed since the arc was generated. An operation of transmitting the starting current reference signal Is to the current error amplifier circuit 43 is performed to promote the generation and expansion of the arc.

Next, the operation of the pulse arc welding apparatus having the configuration shown in FIG. 4 will be described with reference to the waveforms shown in FIGS. 5 (a) to 5 (i). FIG. 4 corresponds to FIGS.
The symbol (i) is attached.

1. Operation at the start of welding.

When a torch switch (not shown) is operated, the welding wire W
And a base material M, a no-load voltage is applied.

During the period from the application of the no-load voltage to the occurrence of the arc, since the analog switch SW10 of the base period control means 1 is opened by the start control unit 5, the no-load voltage is input to the welding voltage error integration circuit 10. Is prohibited. Thereby, the welding voltage error integration circuit 10 calculates the difference (−Er) between the welding voltage at the zero level and the welding average voltage reference value Er.
Is integrated, the output level becomes zero, and the base current energization end signal is continuously output from the zero cross detection circuit 11 to the peak period control means 2.

When the welding wire W comes into contact with the base material M, an arc is generated,
During a period from the occurrence of the arc until a predetermined time t1 elapses, the starting control unit 5 sends the starting current reference signal Is to the welding current error amplifying circuit 43 of the current control means 4 to transmit the welding current I
Is controlled to a maximum value to promote an increase in arc length.

On the other hand, in response to the base current energization end signal output from the base period control means 1, the peak period control means 2 outputs a peak current energization signal for a predetermined time tp set in advance, and when the time tp elapses, the peak current energization signal is output. Switch. With this base current conduction signal, the analog switch SW41 of the current control means 4 is closed to switch the welding current I to the base current Ib. In this embodiment, as described later,
Even when the base current supply end signal is continuously output from the base period control unit 1 to the peak period control unit 2, the peak period control unit 2 maintains the base current supply period tb at the minimum value tm. It has been like that.

On the other hand, in the base period control means 1, when an arc is generated, the analog switch SW10 is closed, the welding voltage E is applied to the welding voltage error integration circuit 10, and the integration of the difference with the welding average voltage reference value Er is started. As the voltage E rises, the output timing of the base current energization end signal is delayed, thereby increasing the base current energization period tb.

As described above, in the initial stage of welding, the base current supply period tb is minimized by the base period control means 1 and the start control unit 5 controls the start current Is until the time t1 elapses.
Is controlled to control the arc length to quickly reach a predetermined value by accelerating the melting of the welding wire, and thereafter, the base period control means 1 increases the base length with increasing the welding voltage (increase in the arc length). The current conduction period tb is gradually increased, thereby controlling the welding average voltage Ea to be stabilized at the welding average voltage reference value Er and maintaining a predetermined arc length.

2. Operation during steady welding.

When a steady welding state is entered after the above-described initial welding operation, the peak current control signal and the base current control signal are alternately output from the peak period control means 2 by the operation described in FIG. The welding is performed by alternately energizing the peak current Ip or the base current Ib in response to the energization signal of. The operation when the welding average voltage is set low and a short circuit occurs at the time of droplet detachment during the base current energizing period tb, or when the arc length transiently increases and the base voltage Eb
The operation in the case where is increased is the same as the operation described in FIG.

Thus, in the pulse arc welding apparatus of the present invention, as described in the principle description, the base period control means 1
Thereby, the base current conduction period tb can be controlled so that the welding average voltage Ea completely matches the welding average voltage reference value Er,
In addition, since a negative feedback control system is not used, there is no time delay for control compared to the case where a negative feedback circuit is configured using a V / F conversion circuit, etc. Since stable control can be performed and no unstable phenomenon such as hunting occurs, the welding average voltage Ea
Can be significantly improved.

FIG. 6 shows a specific circuit example of the pulse arc welding apparatus of the present invention, in which parts corresponding to those in FIG. 4 are denoted by corresponding reference numerals, and FIG. The portions corresponding to the waveform diagrams of (i) to (i) are denoted by the corresponding reference numerals (a) to (i).

In the figure, a welding voltage error integrating circuit 10 of a base period control means 1 is connected to an inverting input terminal side of an integrating circuit using an operational amplifier 10a, and an inverted and amplified negative level welding voltage output from a welding voltage amplifier circuit AMP2. E and the welding average voltage reference value Er of the positive level set by the welding voltage setting unit 3 are simultaneously added, and the sum of them is obtained and integrated, thereby equivalently calculating the welding voltage E and the welding average voltage reference value Er. The difference is integrated. Diode 10b (using a Schottky barrier diode) does not cause the output level of operational amplifier 10a to drop below zero (actually drops to about -0.2 volts because the forward voltage of the diode drops below zero). In this way, it is a clamp diode for immediately starting the integrated output from the zero level when switched to the peak current conduction period tp. The zero-crossing detection circuit 11 is composed of a comparator 11a in which the reference voltage is set to a zero level. During a period in which an integration signal lower than the zero level is being input to the inverting input terminal side, an "H" level base current supply end signal Is output.
In this embodiment, the comparator 11a of the zero-cross detection circuit 11 is operated by supplying positive and negative DC power.
It is also possible to operate with a DC power supply having only a positive voltage.In this case, in order to prevent a malfunction from being caused by applying an excessively negative voltage to the inverting input terminal side of the comparator 21a, a welding voltage error integration circuit 10 is required. The integrated output level is clamped at -0.2 volts by the diode 10b to prevent malfunction.

The peak period control means 2 includes a monostable multivibrator 2a (hereinafter, referred to as monostable MV) for performing an edge trigger operation (starting at a rising voltage), and a minimum value of a base current conduction period tb.
In addition to setting tm, an adjustment circuit 2b including an AND circuit AND is provided to enable edge triggering of the monostable MV2a even when the base current energization end signal is continuously output. Each time the base current energization end signal is output from the means 1, the monostable MV2a is triggered via the AND circuit AND, and the peak current energization signal is output from the signal output terminal Q for a predetermined time tp determined by the resistor R1 and the capacitor C1. Output. The adjustment circuit 2b obtains the logical product of the terminal of the monostable MV2a (the output terminal of the base current conduction signal) and the base current conduction end signal output from the base period control means 1 by a logical product circuit AND. Even when the base current energization end signal is continuously output at the time of startup, etc., the operation of once lowering the trigger terminal T of the monostable MV2a to the “L” level for a predetermined time according to the resistor R2 and the capacitor C2. This makes it possible to re-start the monostable MV2a with the rising voltage of the AND circuit AND.
Is triggered, and control is performed such that the minimum value of the base current conduction period tb becomes tm.

In this embodiment described above, in the welding voltage error integration circuit 10 of the base period control means 1, error integration is started from zero level when the peak current is applied, and is decreased when the base current is applied to reach the zero level. The voltage integration level discrimination unit (zero cross detection circuit) 11 detects the voltage, but the present invention is not limited to such a configuration. For example, in the welding voltage error integration circuit 10, when the peak current is applied, integration is performed in a direction falling from a predetermined level. It is possible to adopt a circuit configuration in which integration is performed in a rising direction when the base current is supplied, and when the integrated output level matches the level at the start of integration, the voltage integration level discrimination unit 11 detects the integration output level. is there.

FIG. 7 shows an example of a configuration in which the base period control unit 1, the peak period control unit 2, and the activation control unit 5 are replaced with a signal processing unit 8 including a CPU in the welding apparatus of the present invention shown in FIG. As shown, the signal processing unit 8 is connected to a ROM 8a storing a processing program, data, and the like, and a RAM 8b for temporarily storing processing data and the like.

In the welding apparatus having such a configuration, the welding voltage error integration processing and the zero-cross detection processing performed by the base period control means 1 are centrally performed by the signal processing unit 8 according to a program stored in the ROM 8a. In addition, since the peak period control processing performed by the peak period control means 2 is also concentrated on the signal processing unit 8, the number of parts can be reduced, and the program stored in the ROM 8a can be modified. This makes it possible to easily change the processing content, thereby making it easy to design and improving the reliability. In this configuration, a peak period setting unit 20 for manually setting the value of the resistor R1 of the peak period control means 2 shown in FIG. 6 is provided outside.

In FIG. 7, the functions of the base period control unit 1, the peak period control unit 2, and the activation control unit 5 are performed by the signal processing unit 8, but other functions are concentrated in the signal processing unit 8. It is also possible to adopt a configuration in which this is performed. In the above description, the signal processing unit 8 performs the signal processing according to the program stored in the ROM 8a.
In order to improve the processing speed, it is also possible to adopt a configuration in which a microprogram (which is configured by hardware and performs the same processing as the program) is integrally provided in the signal processing unit 8 for processing.

According to the first aspect of the present invention, the base current is controlled by the base period control system not based on the negative feedback control circuit so that the welding average voltage completely matches the reference value for each energization cycle. Since the energization period is controlled in real time, problems such as control time delay and hunting are eliminated, the welding average voltage is low, short-circuiting occurs at the time of droplet detachment, and the arc length changes transiently due to factors such as camera shake. The stability of the average welding voltage can be remarkably improved with respect to all the fluctuation factors of the welding voltage, and welding with a stable arc length can be performed.

According to the second aspect of the present invention, it is possible to provide a welding apparatus capable of realizing the welding method of the first aspect.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a welding apparatus for carrying out the method according to the first aspect of the present invention, FIG. 2 is a waveform diagram of each part, and FIGS. 3 (a) to (c). ) Is a diagram for explaining the principle of control for making the welding average voltage equal to the reference value in each energizing cycle, FIG. 4 is a block diagram showing an example of the block diagram of the welding apparatus according to the second aspect of the present invention, and FIG. FIG. 6 is a waveform diagram of each part, FIG. 6 is a diagram of a specific circuit example, and FIG. 7 is a block configuration diagram of a case where the welding apparatus according to the present invention is configured using a CPU. [Explanation of Signs] 1... Base period control means 2... Peak period control means 10... Welding voltage error integration circuit 11... Voltage integration level discrimination unit (zero cross detection circuit) E... Welding voltage Er. Voltage reference value Ip: peak current Ib: base current M: welding base material tp: peak current conduction period tb: base current conduction period W: welding wire

Continuation of the front page (56) References JP-A-63-20172 (JP, A) JP-A-58-380 (JP, A) JP-A-57-118867 (JP, A) JP-A-61-92784 (JP) JP-A-58-196169 (JP, A) JP-A-2-290675 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/09

Claims (2)

(57) [Claims] 1. A pulse arc welding method in which a peak current and a base current are alternately applied between a welding wire and a welding base material, wherein the peak current applying period is controlled to a predetermined value. In order to control the base current conduction period so that the welding average voltage matches the welding average voltage reference value, the welding voltage detected from the start of the peak current conduction is compared with a predetermined welding average voltage reference value, and The difference integration is started, and when the base current is subsequently supplied, when the integrated output level matches the integration output level at the start of the integration, the supply of the base current is stopped to switch to the supply of the peak current. And the pulse arc welding method. 2. A pulse arc welding apparatus in which a peak current and a base current are alternately supplied between a welding wire and a welding base material, wherein the peak current supplying period is controlled to a predetermined value. A period control means, for controlling the base current energization period so that the average welding voltage matches the average welding voltage reference value, the welding voltage detected from the start of the peak current energization is set to a predetermined welding average voltage reference value; In the same manner, when the base current is applied, the detected welding voltage is compared with the welding average voltage reference value, and the difference is integrated. When the integrated output level of the circuit and the welding voltage error integration circuit match the integrated output level at the start of the integration, the base current supply to the peak period control means is terminated. Pulse arc welding apparatus characterized by comprising a base period control means comprising a voltage integration level determination unit for switching the conduction of the peak current and outputs a signal.