JP2016026880A - Pulsed arc welding output control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome the problem that a fluctuation in arc length often causes the occurrence of long-term short-circuit a plurality of times in pulsed arc welding for which distance between a feed chip and a base material is short.SOLUTION: An output control method for pulsed arc welding for welding a workpiece by carrying a weld current Iw with a peak current Ip during a peak period Tp and a base current Ib during a base period Tb assumed as one pulse cycle, includes: detecting long-term short-circuit in every pulse cycle; and changing the waveform parameters Tp and Ip of the weld current Iw so as to increase heat input to a weld wire in pulse cycles after discrimination if it is discriminated that the long-term short-circuit occurs a plurality of times on the basis of detection of the long-term short-circuit. Therefore, the heat input to the weld wire increases in pulse cycles, so that a state in which globules move without causing short-circuit and arc length is large is provided. As a result, it is possible to get away from a state in which the long-term short-circuit occurs a plurality of times and to return to a stable welding state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an output control method of pulse arc welding in which a welding wire is fed and welding is performed by supplying a welding current having a peak current during a peak period and a base current during a base period as one pulse period.

  A consumable electrode type pulse that feeds a welding wire at a constant speed, energizes a welding current with a pulse waveform with the peak current during the peak period and the base current during the base period as one pulse period, and generates an arc for welding. Arc welding methods are widely used. This pulse arc welding method can perform high-quality welding with less spatter generation on various metal materials such as steel and aluminum with high efficiency.

  FIG. 5 is a general current / voltage waveform diagram in consumable electrode type pulse arc welding. FIG. 4A shows the waveform of the welding current Iw for energizing the arc, and FIG. 4B shows the waveform of the welding voltage Vw applied between the welding wire and the base material. Hereinafter, a description will be given with reference to FIG.

  During the peak period Tp from time t1 to t2, as shown in FIG. 6A, the peak current Ip exceeding the critical value is energized in order to rise and form a droplet and transfer the droplet. As shown in (B), a peak voltage Vp rising with an inclination and proportional to the arc length is applied. During the base period Tb from time t2 to time t3, as shown in FIG. 6A, the base current Ib less than the critical value is energized in order to fall with a slope and not form droplets. As shown in B), the base voltage Vb falls with a slope and is proportional to the arc length. Welding is performed by repeating the times t1 to t3 as one pulse period Tf.

  When the welding wire is a steel wire having a diameter of 1.2 mm, the peak current Ip = 450 to 500 A, the peak period including the rise Tp = 1.5 to 2.0 ms, the pulse period Tf = 4.0 to 10.0 ms, the base The current Ib is set to 30 to 70 A, the rising period and the falling period are set to about 0.5 to 1.0 ms. The shortest time (0.5 ms) is determined by the inductance value of the welding torch, welding cable, reactor with built-in welding power source, and the like for the rising period and the falling period. Further, the rising period and the falling period are set to appropriate values (0.5 to 1.0 ms) according to the welding conditions.

  During the peak period Tp, the tip of the welding wire is melted to grow a droplet, and a constriction due to a pinch force is gradually formed on the top of the droplet. Then, at time t2, the base period Tb is entered, and at time t21 after the welding current Iw falls and converges to the base current Ib, the droplets move to the molten pool. At the time of this transition, the droplets may be elongated and come into contact with the molten pool, and at this time, a short circuit occurs for a short time (mostly less than 0.2 ms). Therefore, as shown in FIG. 5B, at time t21, the welding voltage Vw becomes substantially 0 V, and a short circuit has occurred. As shown in FIG. 5A, the welding current Iw increases after a predetermined time from the time t21 when the short circuit occurs, and returns to the normal value at the time t22 when the short circuit ends. The predetermined time is about 0.1 ms. The reason for increasing the welding current Iw is to release the short circuit and return to the arc generation state at an early stage.

  In consumable electrode type arc welding including pulse arc welding, maintaining the arc length during welding at an appropriate value is important for obtaining good welding quality. This arc length control is performed as follows. The average value Vav of the welding voltage shown in FIG. 5B is substantially proportional to the arc length. For this purpose, the welding voltage average value Vav is detected, and the above pulse is set so that the welding voltage average value Vav becomes equal to the welding voltage setting value Vr (not shown) set to a value corresponding to the appropriate arc length. The period Tf (frequency modulation control), the peak period Tp (pulse width modulation control) or the peak current Ip (peak current modulation control) is changed by feedback control. The base current Ib is set to a predetermined value.

  In the frequency modulation control, the peak period Tp and the peak current Ip are waveform parameters and are set to predetermined values. The pulse period Tf (base period Tb) is feedback controlled.

  In the pulse width modulation control, the peak current Ip and the pulse period Tf are waveform parameters and are set to predetermined values. Then, the peak period (pulse width) Tp is feedback controlled.

  In the peak current modulation control, the peak period Tp and the pulse period Tf are waveform parameters and are set to predetermined values. Then, the peak current Ip is feedback controlled.

  The welding voltage average value Vav is detected by detecting the welding voltage Vw and passing it through a low-pass filter (cutoff frequency of about 1 to 10 Hz).

  In each modulation control, the waveform parameter is set to an appropriate value so as to be in a so-called 1-pulse cycle 1 droplet transfer state in which one droplet transfers during one pulse cycle.

  In the invention of Patent Document 1, a short-circuit between the welding wire and the base material is detected, and it is determined whether the short-circuit occurrence time is an early region, an appropriate region, or a late region with respect to the pulse period. Is automatically adjusted. For example, when the peak period Tp is selected as the waveform parameter to be automatically adjusted, if the short-circuit occurrence timing in the nth pulse cycle is in the early region, the peak period Tp is shortened by 0.1 ms, and the (n + 1) th When the short-circuit occurrence time in the second pulse period is in an appropriate region, the peak engine Tp maintains the value as it is. In addition, when the short-circuit occurrence time in the m-th pulse cycle is in the late region, the peak engine Tp is lengthened by 0.1 ms. n and m are positive integers. In this way, automatic adjustment of waveform parameters is performed.

Japanese Patent No. 2973714

  Depending on the shape of the workpiece (base material), it may be necessary to perform pulse arc welding with the distance between the welding torch tip and the base material (hereinafter referred to as the distance between the power feed tip and the base material) being shorter than the normal value. . In such a case, the arc length fluctuates and it is easy to fall into an unstable state in which a long-term short-circuit in which the short-circuit time is longer than the normal value occurs multiple times. Once in a state where a long-term short circuit occurs a plurality of times, it becomes difficult to escape from that state, the amount of spatter generated increases, and the bead appearance also deteriorates.

  Therefore, in the present invention, even in the pulse arc welding in a state where the distance between the power supply tip and the base material is short, even if a long-term short circuit occurs multiple times due to the variation in the arc length, the state is quickly released and stabilized. It is an object of the present invention to provide an output control method for pulse arc welding that can recover to a welding state.

In order to solve the above-described problems, the invention of claim 1
In an output control method of pulse arc welding in which a welding wire is fed and welding is performed with a welding current having a peak current during a peak period and a base current during a base period as one pulse period,
When a long-term short circuit is detected for each pulse period and it is determined that the long-term short circuit has occurred a plurality of times based on the detection of the long-term short circuit, to the welding wire in the pulse period after the determination The waveform parameter of the welding current is changed so as to increase the heat input, and the long-term short-circuit is a short-circuit of a predetermined reference time or more,
An output control method of pulse arc welding characterized by the above.

The invention of claim 2 is performed by determining that the long-term short-circuit has occurred in a state where the long-term short-circuit has occurred a plurality of times by determining that the long-term short-circuit has occurred at the first reference number of consecutive pulses, The first reference number is an integer of 2 or more.
The output control method for pulse arc welding according to claim 1, wherein:

According to a third aspect of the present invention, the determination that the long-term short-circuit has occurred a plurality of times is made by determining that the long-term short-circuit more than the second reference number has occurred per predetermined unit time. , The second reference number is an integer of 2 or more.
The output control method for pulse arc welding according to claim 1, wherein:

According to a fourth aspect of the present invention, it is determined that the long-term short-circuit has occurred in a state where the long-term short-circuit has occurred a plurality of times. The third reference number is an integer greater than or equal to 2,
The output control method for pulse arc welding according to claim 1, wherein:

In the invention of claim 5, the change of the waveform parameter of the welding current is performed for the pulse period of a predetermined number of times or a predetermined time after the determination.
The output control method of pulse arc welding according to any one of claims 1 to 4.

The invention of claim 6 reduces the feeding speed of the welding wire during the pulse period in which the waveform parameter of the welding current is changing.
The output control method of pulse arc welding according to any one of claims 1 to 5.

  According to the present invention, the heat input to the welding wire increases during the pulse period, so that the droplets move without causing a short circuit and the arc length is long. As a result, it is possible to recover from a stable welding state by escaping from a state where a long-term short circuit occurs a plurality of times.

It is an electric current / voltage waveform diagram for demonstrating the output control method of the pulse arc welding which concerns on Embodiment 1 of this invention. It is a block diagram of the welding power supply for implementing the output control method of the pulse arc welding which concerns on Embodiment 1 of this invention. It is an electric current / voltage waveform diagram for demonstrating the output control method of the pulse arc welding which concerns on Embodiment 2 of this invention. It is a block diagram of the welding power supply for implementing the output control method of the pulse arc welding which concerns on Embodiment 2 of this invention. In a prior art, it is a general electric current and voltage waveform figure in consumable electrode type pulse arc welding.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
In the first embodiment, when a long-term short circuit is detected for each pulse period and it is determined that a long-term short circuit has occurred a plurality of times based on the detection of the long-term short circuit, The waveform parameter of the welding current is changed so that the heat input to the welding wire is increased.

  FIG. 1 is a current / voltage waveform diagram for explaining an output control method of pulse arc welding according to Embodiment 1 of the present invention. (A) shows the waveform of the welding current Iw, (B) shows the waveform of the welding voltage Vw, and (C) shows the waveform of the short circuit determination signal Sd. In the figure, the description of the same operation as in FIG. 5 described above will not be repeated. Although not shown in the figure, the welding wire is fed in a regular manner. Hereinafter, a description will be given with reference to FIG.

  The figure shows waveforms for five cycles. In the pulse period from time t1 to time t2, the peak current Ip is energized during the peak period Tp, and the base current Ib is energized during the base period Tb. In the same figure, it is a case where the long-term short circuit has occurred three times continuously in the pulse period from time t1 to t2, the pulse period from time t2 to t3, and the pulse period from time t3 to t4. Here, when a long-term short circuit is defined, it is a short circuit whose short circuit time is a predetermined reference time or more. As described above, a normal short circuit of less than 0.2 ms may occur even in a stable welding state. Therefore, the reference time is set to a time longer than 0.2 ms in order to distinguish from the normal short circuit, for example, about 0.4 to 1.0 ms. During the short circuit period of time t11 to t12, time t21 to t22, and time t31 to t32, the short circuit determination signal Sd becomes High level as shown in FIG. In this figure, the time length of these three short-circuit periods is a long-term short-circuit longer than the reference time. During this long-term short-circuit period, the welding voltage Vw is substantially 0 V as shown in FIG. 5B, and the welding current Iw increases after a predetermined time has elapsed as shown in FIG.

  When a long-term short circuit occurs in the continuous pulse cycle of the first reference number n1, it is determined that the arc length fluctuates and a long-term short circuit occurs a plurality of times. In the figure, since the first reference number n1 is set to 3, it is determined that a long-term short circuit has occurred a plurality of times.

  Based on the above determination, the waveform parameter of the welding current Iw is changed so that the heat input to the welding wire is increased in the pulse period from time t4 to time t5. In this figure, the waveform parameters are the peak current Ip and the peak period Tp. Both values are increased to increase heat input. As a result, heat input to the welding wire is increased during the pulse period, so that the droplets move without causing a short circuit and the arc length is long. As a result, the state where the long-term short circuit occurs a plurality of times is escaped, and the stable welding state is recovered. Therefore, no short circuit occurs during the pulse period from time t4 to t5.

  In the subsequent pulse period from time t5 to t6, the peak current Ip and the peak period Tp are returned to the normal values before time t4. Since a long-term short circuit has occurred from a state where a plurality of times occur, no short circuit has occurred during this period.

In pulse arc welding with a short distance between the power supply tip and the base material, it can be determined as follows that the arc length has fluctuated and multiple long-term short circuits have occurred.
Discrimination method 1) This is the discrimination method described above, and is performed by discriminating that a long-term short circuit has occurred in the pulse cycle of the first reference number n1. The first reference number n1 is an integer of 2 or more, and is set to about 3 to 10 times.
Discrimination method 2) It is discriminated that a long-term short-circuit has occurred for a second reference number n2 or more per unit time. For example, the unit time is set to 100 ms, and the second reference number n2 is an integer of 2 or more, and is set to about 5 to 20.
Determination method 3) It is determined by determining that a long-term short-circuit of the third reference number n3 or more has occurred per unit number of pulse cycles. Unit count> third reference count n3. For example, the unit number of pulse periods is set to 20, and the third reference number n3 is an integer of 2 or more, and is set to about 5 to 10.

As described above, the waveform parameter of the welding current Iw is changed in order to increase the heat input to the welding wire in the pulse period after determining that a long-term short circuit has occurred in a plurality of times. The waveform parameters are as follows according to the arc length control method.
1) During frequency modulation control, the waveform parameter is the peak current Ip and / or the peak period Tp. In order to increase the heat input, the peak current Ip and / or the peak period Tp is increased.
2) During pulse width modulation control, the waveform parameter is the peak current Ip and / or the pulse period. In order to increase the heat input, the peak current Ip is increased and / or the pulse period is decreased.
3) During peak current modulation control, the waveform parameter is the peak period Tp and / or the pulse period. In order to increase the heat input, the peak period Tp is increased and / or the pulse period is decreased.

  In the case of FIG. 1, the waveform parameter is changed only during one pulse period after the determination to increase the heat input to the welding wire. You may make it change the waveform parameter in the predetermined number of times after discrimination | determination or the pulse period of predetermined time. As a result, it is possible to more reliably escape from the state where the long-term short circuit occurs a plurality of times. The predetermined number of times is about 1 to 10 times, and the predetermined time is about 5 to 100 ms. These values are set by experiment as values that can escape from a state where a long-term short circuit occurs a plurality of times.

  FIG. 2 is a block diagram of a welding power source for carrying out the output control method of pulse arc welding according to the first embodiment of the present invention described above with reference to FIG. Hereinafter, each block will be described with reference to FIG.

  The power supply main circuit PM receives a commercial power supply (not shown) such as three-phase 200V as input, performs output control by inverter control according to a drive signal Dv described later, and outputs a welding current Iw and a welding voltage Vw. Although not shown, the power supply main circuit PM includes a primary rectifier that rectifies commercial power, a capacitor that smoothes the rectified direct current, an inverter circuit that converts the smoothed direct current into high-frequency alternating current according to the drive signal Dv, A high-frequency transformer that steps down the high-frequency alternating current to a voltage value suitable for arc welding, a secondary rectifier that rectifies the stepped-down high-frequency alternating current, and a reactor that smoothes the rectified direct current are provided.

  The welding wire 1 is wound around a wire reel 1a. The welding wire 1 is fed at a feeding speed Fw through the welding torch 4 by the rotation of the feeding roll 5 coupled to the wire feeding motor WM, and an arc 3 is generated between the welding wire 1 and the base material 2 to perform welding. Is done. A welding current Iw is passed through the arc 3, and a welding voltage Vw is applied between the power supply chip (not shown) in the welding torch 4 and the base material 2.

  The welding voltage detection circuit VD detects the welding voltage Vw and outputs a welding voltage detection signal Vd. The welding voltage average value calculation circuit VAV receives the welding voltage detection signal Vd as an input, averages it by passing it through a low-pass filter, and outputs a welding voltage average value signal Vav. The welding voltage setting circuit VR outputs a predetermined welding voltage setting signal Vr. The voltage error amplification circuit EV amplifies an error between the welding voltage setting signal Vr and the welding voltage average value signal Vav, and outputs a voltage error amplification signal Ev.

  The voltage / frequency conversion circuit VF receives the voltage error amplification signal Ev, and outputs a pulse period signal Tf having a frequency corresponding to the value of the voltage error amplification signal Ev. The pulse cycle signal Tf is a signal that becomes a high level for a short time every pulse cycle.

  The short circuit determination circuit SD receives the welding voltage detection signal Vd as described above, outputs a short circuit determination signal Sd that determines a short circuit state based on the value and becomes a high level.

  The long-term short circuit detection circuit SE is set to the High level when the elapsed time of the High level from the time when the short circuit determination signal Sd changes to the High level becomes equal to or more than a predetermined reference time, with the short circuit determination signal Sd as an input. When the short circuit determination signal Sd becomes low level, a long-term short circuit detection signal Se that is reset to low level is output.

  The long-term short-circuit multiple occurrence determination circuit SF receives the above-described long-term short-circuit detection signal Se and the above-described pulse period signal Tf, and generates a plurality of long-term short-circuits by any one of the determination methods 1) to 3) described above with reference to FIG. It is determined whether or not it is in a state, and when it is determined that it has fallen, a long-term short-circuit multiple occurrence determination signal Sf that is at a high level for a predetermined pulse period or a predetermined time is output.

  The peak period setting circuit TPR receives the above-mentioned long-term short-circuit multiple occurrence determination signal Sf and takes a predetermined normal value when the long-term short-circuit multiple occurrence determination signal Sf is at the Low level, and increases above the normal value when at the High level. The peak period setting signal Tpr having the obtained value is output.

  The timer circuit TM receives the peak period setting signal Tpr and the pulse period signal Tf as an input, and each time the pulse period signal Tf changes to a high level, the timer signal becomes a high level only for a period determined by the peak period setting signal Tpr. Output Tm. Accordingly, when the timer signal Tm is at a high level, the peak period is set, and when the timer signal Tm is at a low level, a base period is set.

  The peak current setting circuit IPR takes the above-mentioned long-term short-circuit multiple occurrence determination signal Sf as an input, takes a predetermined normal value when the long-term short-circuit multiple occurrence determination signal Sf is at the low level, and increases above the normal value when at the high level. The peak current setting signal Ipr having the obtained value is output.

The base current setting circuit IBR outputs a predetermined base current setting signal Ibr.

  The switching circuit SW receives the timer signal Tm, the peak current setting signal Ipr, and the base current setting signal Ibr, and when the timer signal Tm is at a high level, the switching circuit SW uses the peak current setting signal Ipr as the current control setting signal Icr. When the low level, the base current setting signal Ibr is output as the current control setting signal Icr.

  The welding current detection circuit ID detects the welding current Iw and outputs a welding current detection signal Id. The current error amplification circuit EI amplifies an error between the current control setting signal Icr and the welding current detection signal Id, and outputs a current error amplification signal Ei. The drive circuit DV receives the current error amplification signal Ei as input, performs PWM control, and outputs a drive signal Dv for driving the inverter circuit of the power supply main circuit PM.

  The welding current average value setting circuit IR outputs a predetermined welding current average value setting signal Ir. The feeding speed setting circuit FR receives the welding current average value setting signal Ir as an input, and corresponds to the value of the welding current average value setting signal Ir by the relational expression between the welding current average value and the feeding speed incorporated in advance. A feed speed setting signal Fr is calculated and output. The feed control circuit FC receives this feed speed setting signal Fr and outputs a feed control signal Fc for feeding the welding wire 1 at a feed speed determined by this value to the wire feed motor WM. To do.

  This figure shows a case where the arc length control method is frequency modulation control. In the case of pulse width modulation control or peak current modulation control, it can be similarly performed by changing the waveform parameter to be changed based on the long-term short-circuit multiple occurrence determination signal Sf to one corresponding to each control method described above.

  According to the first embodiment described above, when a long-term short-circuit is detected for each pulse period and it is determined that a long-term short-circuit has occurred a plurality of times based on the detection of the long-term short-circuit, The waveform parameter of the welding current is changed so that the heat input to the welding wire in the period increases. Thereby, in Embodiment 1, since the heat input to the welding wire increases during the pulse period, the droplets are transferred without causing a short circuit, and the arc length is long. As a result, it is possible to recover from a stable welding state by escaping from a state where a long-term short circuit occurs a plurality of times.

[Embodiment 2]
In the invention of the second embodiment, the feeding speed of the welding wire is reduced during the pulse period in which the waveform parameter of the welding current is changing.

  FIG. 3 is a current / voltage waveform diagram for explaining an output control method of pulse arc welding according to Embodiment 2 of the present invention. (A) shows the waveform of the welding current Iw, (B) shows the waveform of the welding voltage Vw, (C) shows the waveform of the short circuit determination signal Sd, and (D) shows the waveform of the welding. The waveform of the wire feeding speed Fw is shown. Since the waveforms in FIGS. 9A to 9C are the same as those in FIG. 1 described above, description of these waveforms will not be repeated. Hereinafter, a description will be given with reference to FIG.

  As described above, the waveform parameter of the welding current Iw is increased so that the heat input to the welding wire is increased in the pulse period from the time t4 to the time t5 based on the determination that the long-term short circuit has occurred a plurality of times. To change.

  As shown in FIG. 4D, the feeding speed Fw is a predetermined steady feeding speed during the period up to time t4. During the pulse period from time t4 to t5 when the waveform parameter of the welding current Iw is changed so that the heat input to the welding wire is increased based on the determination that the long-term short circuit has occurred a plurality of times. The feeding speed Fw is decelerated from the steady feeding speed. The reduced feeding speed Fw is about 70 to 90% of the steady feeding speed. Then, during the period after time t5, the feeding speed Fw is returned to the steady feeding speed.

  Thus, by changing the waveform parameter of the welding current Iw and decelerating the feeding speed Fw of the welding wire, it is possible to escape from the state in which long-term short-circuiting has occurred a plurality of times in a shorter time.

  FIG. 4 is a block diagram of a welding power source for carrying out the pulse arc welding output control method according to the second embodiment of the present invention described above with reference to FIG. This figure corresponds to FIG. 2 described above, and the same reference numerals are given to the same blocks, and description thereof will not be repeated. In the figure, the feed control circuit FC of FIG. 2 is replaced with a second feed control circuit FC2. Hereinafter, this block will be described with reference to FIG.

  The second feed control circuit FC2 receives the feed speed setting signal Fr and the long-term short-circuit multiple occurrence determination signal Sf as input, and when the long-term short-circuit multiple occurrence determination signal Sf is at the low level, the feed speed setting signal Fr. The wire feed motor supplies a feed control signal Fc for feeding the welding wire 1 at a feed rate obtained by decelerating the steady feed rate by a predetermined rate when the level is high. Output to WM.

  According to the second embodiment described above, the feeding speed of the welding wire is reduced during the pulse period in which the waveform parameter of the welding current is changing. As a result, in this embodiment, in addition to the effects of the first embodiment, the welding current waveform parameter is changed, and the welding wire feeding speed is reduced, so that a long-term short-circuit can be performed multiple times in a shorter time. It is possible to get out of the state where it occurs.

DESCRIPTION OF SYMBOLS 1 Welding wire 1a Wire reel 2 Base material 3 Arc 4 Welding torch 5 Feed roll DV Drive circuit Dv Drive signal EI Current error amplification circuit Ei Current error amplification signal EV Voltage error amplification circuit Ev Voltage error amplification signal FC Feed control circuit Fc Feed control signal FC2 Second feed control circuit FR Feed speed setting circuit Fr Feed speed setting signal Fw Feed speed Ib Base current IBR Base current setting circuit Ibr Base current setting signal Icr Current control setting signal ID Welding current detection circuit Id welding current detection signal Ip peak current IPR peak current setting circuit Ipr peak current setting signal IR welding current average value setting circuit Ir welding current average value setting signal Iw welding current n1 first reference number n2 second reference number n3 third reference number PM Main circuit SD Short circuit detection circuit Sd Short circuit determination signal SE Long-term short-circuit detection circuit Se Long-term Fault detection signal SF long short multiple generation determination circuit Sf long short multiple occurrence determination signal SW switching circuit Tb base period Tf pulse cycle (signal)
TM timer circuit Tm timer signal Tp peak period TPR peak period setting circuit Tpr peak period setting signal VAV welding voltage average value calculation circuit Vav welding voltage average value (signal)
Vb Base voltage VD Welding voltage detection circuit Vd Welding voltage detection signal VF Voltage / frequency conversion circuit Vp Peak voltage VR Welding voltage setting circuit Vr Welding voltage setting (value / signal)
Vw Welding voltage WM Wire feed motor

Claims (6)

In an output control method of pulse arc welding in which a welding wire is fed and welding is performed with a welding current having a peak current during a peak period and a base current during a base period as one pulse period,
When a long-term short circuit is detected for each pulse period and it is determined that the long-term short circuit has occurred a plurality of times based on the detection of the long-term short circuit, to the welding wire in the pulse period after the determination The waveform parameter of the welding current is changed so as to increase the heat input, and the long-term short-circuit is a short-circuit of a predetermined reference time or more,
An output control method of pulse arc welding characterized by the above. The determination that the long-term short circuit has occurred a plurality of times is performed by determining that the long-term short circuit has occurred in the pulse period of the first reference number that is continuous, and the first reference number is 2 or more. Is an integer of
The output control method of pulse arc welding according to claim 1. The determination that the long-term short-circuit has occurred a plurality of times is performed by determining that the long-term short-circuit has occurred more than a second reference number per predetermined unit time, and the second reference number is An integer greater than or equal to 2,
The output control method of pulse arc welding according to claim 1. The determination that the long-term short-circuit has occurred a plurality of times is performed by determining that the long-term short-circuit has occurred more than a third reference number per predetermined period of the pulse period, 3 The standard number is an integer greater than or equal to 2,
The output control method of pulse arc welding according to claim 1. The change of the waveform parameter of the welding current is performed with respect to the pulse period of a predetermined number of times or a predetermined time after the determination,
The output control method of pulse arc welding according to any one of claims 1 to 4. During the pulse period in which the waveform parameter of the welding current is changing, the feeding speed of the welding wire is reduced.
The output control method of pulse arc welding according to any one of claims 1 to 5.

Images