JP2020151748A - Pulse arc welding control method - Google Patents

Abstract

To suppress that a welding state becomes unstable even if short circuit is erroneously determined when a welding cable reciprocating length is long in pulse arc welding.SOLUTION: According to a pulse arc welding control method, a welding wire is fed, ascent transition current Iu rising from base current Ib to peak current Ip is electrically conducted during a rise period Tu, the peak current IP is electrically conducted during a peak period Tp, descent transition current Ik dropping from the peak current Ip to the base current IB is electrically conducted during a falling period Tk, the base current Ib is electrically conducted during a base period Tb, electrical conduction of these welding currents Iw is repeated as one pulse period, short circuit between the welding wire and a base material is determined by an output voltage in a welding power source, and short circuit current Is is electrically conducted. In this method, short circuit current control, such that a rate S of increase of the short circuit current Is becomes smaller as a welding cable reciprocating length becomes longer, is performed.SELECTED DRAWING: Figure 2

Description

The present invention relates to a consumable electrode type pulse arc welding method.

Consumable electrode type pulse arc welding (hereinafter, simply referred to as pulse arc welding) is widely used for welding steel, aluminum, stainless steel and the like. In this pulse arc welding, an ascending transition current that rises from the base current to the peak current is energized during the rising period, a peak current is energized during the peak period, and the peak current drops to the base current during the falling period. Welding is performed by energizing the descending transition current, energizing the base current during the base period, and repeating energization of these welding currents as one pulse cycle.

In pulse arc welding, a short circuit sometimes occurs between the welding wire and the base metal due to droplet transfer. The frequency of short circuits increases as the welding voltage setting value decreases. Short circuits most often occur during the fall or base period. In order to release this short circuit at an early stage and regenerate the arc, short-circuit current control is performed to energize the short-circuit current that rises when the short-circuit is determined (see Patent Document 1). ..

Japanese Unexamined Patent Publication No. 2016-22507

As described above, in the prior art, short-circuit current control is performed in pulse arc welding to determine a short circuit and increase the welding current. The short circuit is determined by detecting the welding voltage Vw between the power feeding tip attached to the welding torch and the base metal, and setting the period during which this voltage value is equal to or less than the short circuit determination value of about 10 V as the short circuit period. There is. The positive side of the output terminal of the welding power supply and the welding torch, and the negative side of the output terminal and the base metal are connected by welding cables, respectively. When the short circuit is discriminated by the above welding voltage Vw, it can be accurately discriminated. However, in order to detect the welding voltage Vw, it is necessary to lay a detection line outside the welding power source, which causes a problem that the installation man-hours increase. Further, there is a problem that the detection line is drawn many times during the welding operation, resulting in cutting and making welding impossible. For this reason, usually, the output voltage Vo in the welding power supply is detected and used as a substitute for determining the short circuit.

Here, assuming that the welding current is Iw, the resistance value of the reciprocating welding cable is R, and the inductance value of the reciprocating welding cable is L, the following equation is established.
Vo = Vw + R ・ Iw + L ・ dIw / dt
Since the resistance value R is a small value and can be ignored, the following equation is obtained.
Vo = Vw + L · dIw / dt ... When the reciprocating length of the (1) type welding cable is short, the inductance value L becomes small, so Vo becomes almost equal to Vw, and the short circuit is accurate depending on the output voltage Vo in the welding power supply. Can be determined.

When the reciprocating length of the welding cable becomes long, the inductance value L becomes large and is affected by the voltage due to L · dIw / dt. As mentioned above, short circuits most often occur during the fall or base period. Since a constant value of base current is energized during the base period, L · dIw / dt = 0, so that a short circuit can be accurately determined. However, during the falling period, a falling transition current that sharply drops from the peak current to the base current is energized. For this reason, L · dIw / dt becomes a large negative value, and the output voltage Vo in the welding power supply becomes a value significantly smaller than the welding voltage Vw. As a result, it is erroneously determined that it is a short-circuit period even though it is an arc period.

To summarize the above, when determining a short circuit based on the output voltage Vo in the welding power supply, when the reciprocating length of the welding cable is long, it is misunderstood that it is a short circuit period even though it is an arc period during the falling period. Another happens. If misidentified, the welding current will inadvertently increase and the welding state will become unstable.

Therefore, in the present invention, when the short circuit is determined by the output voltage in the welding power supply, when the reciprocating length of the welding cable is long, the welding state becomes unstable due to the erroneous determination of the short circuit during the falling period. It is an object of the present invention to provide a pulse arc welding control method that can be suppressed.

In order to solve the above-mentioned problems, the invention of claim 1 is
Along with feeding the welding wire, an ascending transition current that rises from the base current to the peak current is energized during the rising period, the peak current is energized during the peak period, and the peak current is applied to the base during the falling period. The descending transition current that descends to the current is energized, the base current is energized during the base period, and the energization of these welding currents is repeated as one pulse cycle.
In the pulse arc welding control method in which a short circuit between the welding wire and the base metal is discriminated by the output voltage in the welding power source and a short circuit current is applied.
Short-circuit current control is performed so that the rate of increase of the short-circuit current decreases as the reciprocating length of the welding cable increases.
This is a pulse arc welding control method characterized by the above.

The invention of claim 2 is
Along with feeding the welding wire, an ascending transition current that rises from the base current to the peak current is energized during the rising period, the peak current is energized during the peak period, and the peak current is applied to the base during the falling period. The descending transition current that descends to the current is energized, the base current is energized during the base period, and the energization of these welding currents is repeated as one pulse cycle.
In the pulse arc welding control method in which a short circuit between the welding wire and the base metal is discriminated by the output voltage in the welding power source and a short circuit current is applied.
The short-circuit current control is performed so that the rate of increase of the short-circuit current is smaller during the fall period than during the base period.
This is a pulse arc welding control method characterized by the above.

According to the present invention, in pulse arc welding, when a short circuit is determined by the output voltage in the welding power supply, when the reciprocating length of the welding cable is long, the welding state is not good due to erroneous determination of the short circuit during the falling period. It can be suppressed from becoming stable.

It is a block diagram of the welding apparatus for carrying out the pulse arc welding control method which concerns on Embodiment 1 of this invention. It is a current / voltage waveform diagram in the welding apparatus of FIG. 1 which shows the pulse arc welding control method which concerns on Embodiment 1 of this invention. It is a block diagram of the welding apparatus for carrying out the pulse arc welding control method which concerns on Embodiment 2 of this invention. It is a current / voltage waveform diagram in the welding apparatus of FIG. 3 which shows the pulse arc welding control method which concerns on Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
According to the first embodiment, in pulse arc welding, short-circuit current control is performed in which the rate of increase in short-circuit current decreases as the reciprocating length of the welding cable increases.

FIG. 1 is a block diagram of a welding apparatus for carrying out the pulse arc welding control method according to the first embodiment of the present invention. The welding device is mainly composed of a welding power supply PS surrounded by a broken line, a robot control device RC, a robot (not shown), and the like. Hereinafter, each block will be described with reference to the figure.

The welding power supply PS is composed of the following blocks. However, the circuit for controlling the feeding and feeding of the welding wire 1 at a constant speed is omitted.

The power supply main circuit MC receives an AC commercial power supply (not shown) such as 3-phase 200V as an input, performs output control such as inverter control according to a drive signal Dv described later, and obtains an output voltage Vo and welding current Iw suitable for welding. Output. Although not shown, the power supply main circuit MC includes a primary rectifier circuit that rectifies an AC commercial power supply, a capacitor that smoothes the rectified DC, and an inverter circuit that converts the smoothed DC into high-frequency AC according to the drive signal Dv. It is equipped with an inverter transformer that steps down high-frequency AC to a voltage value suitable for welding, and a secondary rectifier circuit that rectifies the stepped-down high-frequency AC. The reactor WL is inserted between the + side output of the power supply main circuit MC and the plus side of the output terminal of the welding power supply to smooth the output of the power supply main circuit MC.

The welding wire 1 is fed in the welding torch 4 by the rotation of the feeding roll 5 of the wire feeder (not shown), and an arc 3 is generated between the welding wire 1 and the base metal 2. The wire feeder and the welding torch 4 are mounted on the robot. A welding voltage Vw is applied between the power feeding tip (not shown) in the welding torch 4 and the base metal 2, and the welding current Iw is energized. The positive side of the output terminal of the welding power supply PS and the welding torch 4 and the negative side of the output terminal and the base metal 2 are connected by welding cables, respectively.

The voltage detection circuit VD detects the output voltage Vo in the welding power supply and outputs the voltage detection signal Vd. The voltage averaging circuit VAV averages the voltage detection signal Vd (passes it through a low-pass filter) and outputs the voltage averaging signal Vav.

The voltage setting circuit VR outputs a predetermined voltage setting signal Vr.

The voltage error amplifier circuit EV amplifies the error between the voltage setting signal Vr (+) and the voltage average signal Vav (−), and outputs a voltage error amplification signal Ev.

The V / F converter VF outputs a pulse period signal Tf, which is a trigger signal that becomes a high level for a short time at a frequency corresponding to the voltage error amplification signal Ev. The period in which the pulse period signal Tf becomes the High level for a short time is one pulse period.

The rise period setting circuit TUR outputs a predetermined rise period setting signal Tur. The peak period setting circuit TPR outputs a predetermined peak period setting signal Tpr. The fall period setting circuit TKR outputs a predetermined fall period setting signal Tkr.

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

The current setting circuit IR includes the pulse period signal Tf, the rise period setting signal Tur, the peak period setting signal Tpr, the fall period setting signal Tkr, the peak current setting signal Ipr, and the base current. With the setting signal Ibr as an input, each time the pulse period signal Tf changes to the High level for a short time, the following processing is performed and the current setting signal Ir is output.
1) During the period determined by the rise period setting signal Tur, the current setting signal Ir that linearly rises from the value of the base current setting signal Ibr to the value of the peak current setting signal Ipr is output.
2) Subsequently, the peak current setting signal Ipr is output as the current setting signal Ir during the period determined by the peak period setting signal Tpr.
3) Subsequently, during the period determined by the falling period setting signal Tkr, the current setting signal Ir that linearly decreases from the value of the peak current setting signal Ipr to the value of the base current setting signal Ibr is output.
4) Subsequently, the base current setting signal Ibr is output as the current setting signal Ir during the period until the pulse period signal Tf reaches the High level again for a short time.

The short-circuit discrimination circuit SD takes the above voltage detection signal Vd as an input, and when this value is less than the short-circuit discrimination value, it determines that it is a short-circuit period and reaches the High level, and when it is more than that, it determines that it is an arc period. The short-circuit determination signal Sd that becomes the Low level is output. The short circuit discrimination value is set to about 10V.

The welding cable reciprocating length setting circuit CR outputs a welding cable reciprocating length setting signal Cr for setting the reciprocating length of the welding cable. For this setting, the welding operator may manually set the welding cable reciprocating length setting knob provided on the front panel of the welding power supply. Further, when a welding robot is used, it may be set from the robot control device RC. The welding cable reciprocating length setting signal Cr is, for example, numerical data of 5 to 50 m.

The rise rate setting circuit SR receives the above-mentioned welding cable reciprocating length setting signal Cr as an input, calculates the rise rate by a predetermined calculation function, and outputs the rise rate setting signal Sr. An example of the calculation function is shown below.
Sr = 100-Cr
Here, since the range of Cr is about 5 to 50 m, the setting range of the ascending rate setting signal Sr is 95 to 50 (A / ms). That is, the longer the welding cable reciprocating length setting signal Cr, the smaller the rising rate setting signal Sr. In the above, the value of the rising rate setting signal Sr changes continuously, but it may change in a stepwise manner. For example, when Cr ≦ 25, Sr = 95 may be set, and when Cr> 25, Sr = 50 may be set.

The current control setting circuit ICR receives the above current setting signal Ir, the above rise rate setting signal Sr, and the above short circuit discrimination signal Sd as inputs, and when the short circuit discrimination signal Sd is the Low level (arc period), the current setting signal Ir. Is output as the current control setting signal Icr. The current control setting signal Icr that increases with the rate is output.

The current detection circuit ID detects the welding current Iw and outputs the current detection signal Id. The current error amplifier circuit EI amplifies the error between the current control setting signal Icr (+) and the current detection signal Id (−), and outputs the current error amplification signal Ei. The drive circuit DV receives the current error amplification signal Ei and the start signal On from the robot control device RC described later as inputs, and when the start signal On is at the High level (start of welding), PWM modulation is performed based on the current error amplification signal Ei. It controls and outputs the drive signal Dv for driving the inverter circuit in the power supply main circuit MC, and does not output the drive signal Dv when the start signal On is at the Low level (welding stop).

The robot control device RC moves the robot (not shown) according to a work program taught in advance, and outputs a start signal On instructing welding start or welding stop.

FIG. 2 is a current / voltage waveform diagram in the welding apparatus of FIG. 1 showing a pulse arc welding control method according to the first embodiment of the present invention. FIG. 3A shows a time change of the welding current Iw, FIG. 2B shows a time change of the welding voltage Vw, and FIG. 3C shows a time change of the short circuit discrimination signal Sd. In the figure, the activation signal On from the robot control device is at the High level, and is a waveform during welding. Hereinafter, description will be made with reference to the figure.

The welding voltage Vw shown in FIG. 6B is a voltage between the welding wire and the base metal (voltage between the feeding chip and the base metal), and is a voltage value that is not affected by the inductance value L of the welding cable. The short-circuit discrimination signal Sd shown in FIG. 3C is a signal for discriminating between the short-circuit period and the arc period based on the value of the output voltage Vo in the welding power supply. Therefore, when the reciprocating length of the welded cable becomes long and the inductance value L becomes large, as described above in Eq. (1), a large negative value due to L · dIw / dt is superimposed during the falling period, and a short-circuit discrimination signal is signaled. Misidentification of Sd occurs.

The figure shows waveforms for two cycles, a pulse period Tf at times t1 to t2 and a pulse period Tf at times t2 to t3. In the pulse period Tf at times t1 to t2, during the rise period Tu, as shown in FIG. (A), the rising transition current Iu rising from the base current Ib to the peak current Ip is energized, and FIG. As shown in, an ascending transition voltage that rises from the base voltage Vb to the peak voltage Vp is applied between the welding wire and the base metal. During the subsequent peak period Tp, as shown in FIG. (A), a peak current Ip having a large current value equal to or higher than the critical value is energized in order to transfer droplets from the welding wire, and as shown in FIG. Is applied with a peak voltage Vp proportional to the arc length. During the subsequent falling period Tk, as shown in FIG. 3A, the falling transition current Ik falling from the peak current Ip to the base current Ib is energized, and as shown in FIG. A downward transition voltage that descends from to the base voltage Vb is applied. During the subsequent base period Tb, as shown in FIG. 2A, a base current Ib having a small current value less than the critical value is energized in order to prevent the formation of droplets, and as shown in FIG. Is applied with a base voltage Vb proportional to the arc length. The same applies during the pulse period Tf at times t2 to t3. Each parameter has, for example, peak current Ip = 450 to 550A, base current Ib = 30 to 70A, peak period Tp = 1.0 to 1.5ms, rise period Tu = 0.5 to 1.5ms, fall period Tk. = It is set to about 0.5 to 1.5 ms.

In the pulse period Tf at times t1 to t2, the short-circuit discrimination signal Sd changes to the High level at time t11 during the falling period Tk, as shown in FIG. However, as shown in FIG. 6B, since the welding voltage Vw is an arc voltage value equal to or higher than the short-circuit discrimination value, the short-circuit is erroneously discriminated. The welding power source starts short-circuit current control when the short-circuit determination signal Sd reaches the High level. As shown in FIG. 6A, the welding current Iw rises from time t11 by controlling the short-circuit current. The increase rate S of the short-circuit current Is is set by the increase rate setting signal Sr of FIG. When the erroneous determination of the short circuit is completed at the time t12, the short circuit determination signal Sd returns to the Low level. In response to this, the welding current Iw drops to the current value set by the current setting signal Ir in FIG.

As described above in FIG. 1, the value of the rising rate setting signal Sr is automatically set by a predetermined calculation function according to the value of the welding cable reciprocating length setting signal Cr. In the case of the calculation function illustrated in FIG. 1, when the value of the welding cable reciprocating length setting signal Cr is set in the range of 5 to 50 m, the value of the rise rate setting signal Sr is in the range of 95 to 50 (A / ms). It changes with. Therefore, the longer the welding cable reciprocating length setting signal Cr, the smaller the rising rate setting signal Sr.

As described above, when the reciprocating length of the welding cable becomes long, the inductance value L becomes large, and a short circuit is erroneously determined during the falling period Tk, the rate of increase S of the short circuit current Is is short. Is controlled to be smaller than. As a result, it is possible to prevent the short-circuit current Is from rising sharply and the welding state from becoming unstable when a short-circuit is erroneously determined. However, even when a short circuit is truly generated during the falling period, the rate of increase S of the short circuit current Is remains small. This slightly increases the amount of spatter generated, but the welding quality is better than the welding state becoming unstable.

Next, in the pulse period Tf at times t2 to t3, the short-circuit discrimination signal Sd changes to the High level at time t21 during the base period Tb, as shown in FIG. At this time, as shown in FIG. 6B, the welding voltage Vw is also a short-circuit voltage value of several V, and a short circuit is truly generated. As described above, since L · dIw / dt is almost 0 during the base period Tb, the short circuit can be accurately determined by the output voltage Vo in the welding power supply. The welding power source starts short-circuit current control when the short-circuit determination signal Sd reaches the High level. As shown in FIG. 6A, the welding current Iw rises from time t21 by controlling the short-circuit current. The rate of increase S of the short-circuit current Is is the same as that from the time t11. At time t12, when the short circuit ends and the arc period begins, the short circuit determination signal Sd returns to the Low level. In response to this, the welding current Iw drops to the base current value Ib set by the current setting signal Ir in FIG.

When the welding cable reciprocating length setting signal Cr is set to a large value, if a short circuit occurs during the base period Tb, the rate of increase in the short circuit current is suppressed. As a result, the amount of spatter generated increases a little, but the welding quality is better than the welding state becomes unstable due to the erroneous determination of a short circuit during the falling period Tk.

[Embodiment 2]
The invention of the second embodiment provides short-circuit current control in pulse arc welding in which the rate of increase of the short-circuit current when a short-circuit is determined by the output voltage in the welding power source is smaller during the fall period than during the base period. It is what you do.

FIG. 3 is a block diagram of a welding apparatus for carrying out the pulse arc welding control method according to the second embodiment of the present invention. This figure corresponds to FIG. 1 described above, and the same blocks are designated by the same reference numerals, and the description thereof will not be repeated. In the figure, the current setting circuit IR of FIG. 1 is replaced with the second current setting circuit IR2, and the rise rate setting circuit SR of FIG. 1 is replaced with the second rise rate setting circuit SR2. Hereinafter, these blocks will be described with reference to the figure.

The second current setting circuit IR2 includes the pulse period signal Tf, the rise period setting signal Tur, the peak period setting signal Tpr, the fall period setting signal Tkr, the peak current setting signal Ipr, and the above. With the base current setting signal Ibr as an input, each time the pulse period signal Tf changes to the High level for a short time, the following processing is performed, and the current setting signal Ir and the fall period signal Stk are output. The falling period signal Stk is a signal that has a high level during the falling period and a low level during the other period.
1) During the period determined by the rise period setting signal Tur, the current setting signal Ir that linearly rises from the value of the base current setting signal Ibr to the value of the peak current setting signal Ipr is output.
2) Subsequently, the peak current setting signal Ipr is output as the current setting signal Ir during the period determined by the peak period setting signal Tpr.
3) Subsequently, during the period determined by the falling period setting signal Tkr, the current setting signal Ir that linearly decreases from the value of the peak current setting signal Ipr to the value of the base current setting signal Ibr is output. Only during this fall period, the fall period signal Stk that becomes the High level is output.
4) Subsequently, the base current setting signal Ibr is output as the current setting signal Ir during the period until the pulse period signal Tf reaches the High level again for a short time.

The second rise rate setting circuit SR2 receives the above-mentioned fall period signal Stk as an input, and when the fall period signal Stk is at the Low level, it becomes the predetermined first rise rate, and when the fall period signal Stk is at the High level. Outputs a rise rate setting signal Sr, which is a predetermined second rise rate. Here, the first rate of increase is a value larger than the second rate of increase. Therefore, the rate of increase of the short-circuit current is smaller during the fall period than during the base period. For example, the first rate of increase = 95 (A / ms) and the second rate of increase = 50 (A / ms).

FIG. 4 is a current / voltage waveform diagram in the welding apparatus of FIG. 3 showing a pulse arc welding control method according to the second embodiment of the present invention. FIG. 3A shows a time change of the welding current Iw, FIG. 2B shows a time change of the welding voltage Vw, and FIG. 3C shows a time change of the short circuit discrimination signal Sd. This figure corresponds to FIG. 2 described above, and points different from FIG. 2 will be described. Hereinafter, description will be made with reference to the figure.

In the pulse period Tf at times t1 to t2, the short-circuit discrimination signal Sd changes to the High level at time t11 during the falling period Tk, as shown in FIG. However, as shown in FIG. 6B, since the welding voltage Vw is an arc voltage value equal to or higher than the short-circuit discrimination value, the short-circuit is erroneously discriminated. The welding power source starts short-circuit current control when the short-circuit determination signal Sd reaches the High level. As shown in FIG. 6A, the welding current Iw rises from time t11 by controlling the short-circuit current. The increase rate S of the short-circuit current Is is set by the increase rate setting signal Sr output from the second increase rate setting circuit SR2 of FIG. Since this period is during the falling period Tk, the rising rate setting signal Sr becomes a predetermined second rising rate. This second rate of increase is smaller than the predetermined first rate of increase during the base period Tb.

When the erroneous determination of the short circuit is completed at the time t12, the short circuit determination signal Sd returns to the Low level. In response to this, the welding current Iw drops to the current value set by the current setting signal Ir in FIG.

In this way, when the reciprocating length of the welding cable becomes long, the inductance value L becomes large, and a short circuit is erroneously determined during the falling period Tk, the rate of increase S of the short circuit current Is causes a short circuit during the base period Tb. It is controlled to be smaller than when it is determined. As a result, it is possible to prevent the short-circuit current Is from rising sharply and the welding state from becoming unstable when a short-circuit is erroneously determined. However, when a short circuit really occurs during the falling period and when the short circuit is accurately determined due to the short reciprocating length of the welding cable, the rate of increase in the short circuit current remains small. This slightly increases the amount of spatter generated, but the welding quality is better than the welding state becoming unstable.

Next, in the pulse period Tf at times t2 to t3, the short-circuit discrimination signal Sd changes to the High level at time t21 during the base period Tb, as shown in FIG. At this time, as shown in FIG. 6B, the welding voltage Vw is also a short-circuit voltage value of several V, and a short circuit is truly generated. As described above, since L · dIw / dt is almost 0 during the base period Tb, the short circuit can be accurately determined by the output voltage Vo in the welding power supply. The welding power source starts short-circuit current control when the short-circuit determination signal Sd reaches the High level. As shown in FIG. 6A, the welding current Iw rises from time t21 by controlling the short-circuit current. The increase rate S of the short-circuit current Is is set by the increase rate setting signal Sr, which is an output signal from the second increase rate setting circuit SR2 of FIG. Since this period is not the falling period Tk, the rise rate setting signal Sr is the first rise rate. This first rate of increase is larger than the second rate of increase during the fall period Tk.

At time t12, when the short circuit ends and the arc period begins, the short circuit determination signal Sd returns to the Low level. In response to this, the welding current Iw drops to the base current value Ib set by the current setting signal Ir in FIG.

As described above, during the base period Tb, the short circuit can be accurately discriminated regardless of the length of the reciprocating length of the welding cable. Therefore, by setting the rate of increase of the short-circuit current during the base period Tb to be larger than that during the fall period Tk, the short-circuit can be canceled early, and the occurrence of sputtering can be reduced.

In the first and second embodiments described above, the rate of increase S of the short-circuit current Is is controlled by constant current control. In addition to this, the rate of increase S of the short-circuit current Is may be performed by electronic reactor control, which is a conventional technique.

1 Welding wire 2 Base material 3 Arc 4 Welding torch 5 Feeding 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 Ib Base current IBR Base current setting circuit I Base current setting signal ICR Current control setting circuit Icr Current control setting signal ID Current detection circuit Id Current detection signal Ik Downward transition current Ip Peak current IPR Peak current setting circuit Ipr Peak current setting signal IR Current setting circuit Ir Current setting signal IR2 2nd Current setting circuit Is Short-circuit current Iu Rise transition current Iw Welding current MC Power supply Main circuit On Start signal PS Welding power supply RC Robot controller S Rise rate SD Short-circuit discrimination circuit Sd Short-circuit discrimination signal SR Rise rate setting circuit Sr Rise rate setting signal SR2 2 Rise rate setting circuit Tb Base period Tf Pulse period (signal)
Tk Rising period TKR Rising period setting circuit Tkr Rising period setting signal Tp Peak period TPR Peak period setting circuit Tpr Peak period setting signal Tu Rising period TUR Rising period setting circuit Tur Rising period setting signal VAV Voltage averaging circuit Vav Voltage averaging Signal Vb Base voltage VD Voltage detection circuit Vd Voltage detection signal VF V / F converter Vo Output voltage in welding power supply Vp Peak voltage VR Voltage setting circuit Vr Voltage setting signal Vw Welding voltage WL Reactor

Claims (2)

Along with feeding the welding wire, an ascending transition current that rises from the base current to the peak current is energized during the rising period, the peak current is energized during the peak period, and the peak current is applied to the base during the falling period. The descending transition current that descends to the current is energized, the base current is energized during the base period, and the energization of these welding currents is repeated as one pulse cycle.
In the pulse arc welding control method in which a short circuit between the welding wire and the base metal is discriminated by the output voltage in the welding power source and a short circuit current is applied.
Short-circuit current control is performed so that the rate of increase of the short-circuit current decreases as the reciprocating length of the welding cable increases.
A pulse arc welding control method characterized by this. Along with feeding the welding wire, an ascending transition current that rises from the base current to the peak current is energized during the rising period, the peak current is energized during the peak period, and the peak current is applied to the base during the falling period. The descending transition current that descends to the current is energized, the base current is energized during the base period, and the energization of these welding currents is repeated as one pulse cycle.
In the pulse arc welding control method in which a short circuit between the welding wire and the base metal is discriminated by the output voltage in the welding power source and a short circuit current is applied.
The short-circuit current control is performed so that the rate of increase of the short-circuit current is smaller during the fall period than during the base period.
A pulse arc welding control method characterized by this.

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