KR20140136378A - Output control method of pulse arc welding - Google Patents

Abstract

According to the present invention, when a pulse arc welding process is performed, pulse parameters such as peak time (Tp) and peak currents (Ip) are automatically adjusted and stabilized to be in optimized values. The present invention relates to a method for controlling output of pulse arc welding whereby welding wires are supplied and the pulse arc welding process is repeated in a cycle (Tf) of one pulse, which is conduction of the peak currents (Ip) during the peak time (Tp) and base currents (Ib) during base time (Tb). For every pulse cycle, time (t21) when short circuits of the welding wire and a base material occur is checked; an index presenting distribution of short circuit occurrence per unit time is calculated. Based on the index, the pulse parameters, such as the peak time (Tp) and the peak currents (Ip) with respect to a waveform (Iw) of welding electric currents, are automatically adjusted. Likewise, the value, statistically calculated from the distribution of short circuit occurrence per unit time, is used for automatic adjustment. Therefore, even when a droplet transfer timing varies, the pulse parameters can be stably and automatically adjusted.

Description

TECHNICAL FIELD [0001] The present invention relates to an output control method for pulsed arc welding,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse arc welding output control method in which a welding wire is fed and a peak current during a peak period and a base current during a base period are repeatedly welded with one pulse cycle, .

A consumable electrode type pulse arc welding method is widely used in which a welding wire is fed at a constant speed and an arc is generated by welding a pulse current having a peak current during a peak period and a base current during a base period in one pulse period . This pulse arc welding method can perform high-quality welding with a small amount of spatter generated for various metal materials such as steel and aluminum with high efficiency.

Fig. 5 is a general current / voltage waveform chart in consumable electrode type pulse arc welding. 6A shows the waveform of the welding current Iw for energizing the arc, and FIG. 6B shows the waveform of the welding voltage Vw applied between the welding wire and the base material. This will be described below with reference to the drawings.

During the peak period Tp of the time t1 to t2, as shown in (A) of Fig. 6, the peak current Ip having a threshold value or more is energized to rise with a slope, to form a volume, , A peak voltage Vp proportional to the arc length is applied. During the base period Tb of the times t2 to t3, the base current Ib lower than the threshold value is energized so as not to form a volume, with the inclination falling, as shown in (A) , A base voltage Vb proportional to the arc length is applied. The welding is repeated by repeating the times t1 to t3 at 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 Tp = 1.5 to 2.0 ms including the rise, the pulse period Tf = 4.0 to 10.0 ms, the base current Ib = 30 to 70 A, The rising period and the falling period = 0.5 to 1.0 ms.

During the peak period Tp, the tip of the welding wire is melted and the volume grows, and a constriction due to the pinching force is gradually formed on the volume. Then, at a time t21 immediately after the welding current Iw falls and converges to the base current Ib, the volume shifts to the melting furnace at the time t2. At this transition, the volume becomes elongated and elongated and comes into contact with the fusing paper, resulting in a short-time (usually less than 0.2 ms) short-circuit. Therefore, as shown in (B) of Fig. 6, at time t21, the welding voltage Vw becomes approximately 0 V and a short circuit occurs. There is no change in the welding current Iw shown in (A) of Fig. However, when the short-circuit period becomes longer than the reference time (for example, 1 ms), the welding current Iw is gradually increased in order to release the short-circuit earlier. From the above, it is possible to detect the volume transition timing by detecting the occurrence of a short circuit.

In consumable electrode arc welding including pulse arc welding, it is important to maintain the arc length during welding at an appropriate value to obtain a good welding quality. This arc length control is performed as follows. The average value Vav of the welding voltage shown in (B) of the figure is approximately proportional to the arc length. Therefore, the welding voltage average value Vav is detected, and the pulse period Tf (frequency modulation control) is performed so that the welding voltage average value Vav becomes equal to the welding voltage set value Vr (not shown) set to a value corresponding to the proper arc length. , 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 become pulse parameters and are set to predetermined values. Then, the pulse period Tf (base period Tb) is feedback-controlled.

In the pulse width modulation control, the pulse period Tf and the peak current Ip become pulse parameters and 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 become pulse parameters and 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 pulse parameter is set to an appropriate value so as to be a so-called one-pulse-period-one-volume transition state in which one volume is shifted during one pulse period. Particularly, when the volume transition timing is performed within a predetermined time period from the end point of the peak period Tp through the falling period, the pulse parameter is set to the optimum value.

The optimum value of the pulse parameter is a welding wire having the same JIS standard, but a different value depending on the item of the welding wire. Furthermore, the optimum value varies depending on the distance between the feed chip and the base material (torch height), feed speed, welding speed, and the like. For this reason, control for automatically adjusting the pulse parameter to an optimum value has been proposed (see Patent Document 1).

In the invention of Patent Document 1, a short circuit is detected between the welding wire and the base material, and it is determined whether the short-circuit occurrence timing is an early region, a preliminary region or a late region with respect to the pulse cycle. will be. For example, when the peak period Tp is selected as the pulse parameter to be automatically adjusted, when the short-circuit occurrence period in the n-th pulse period is early, the peak period Tp is shortened by 0.1 ms, When the short-circuit occurrence period in the +1 th pulse cycle is the titrator region, the peak organ Tp remains unchanged. When the short-circuit occurrence period in the m-th pulse period is the late region, the peak organ Tp is made longer by 0.1 ms. n and m are positive integers. In this manner, the pulse parameters are automatically adjusted.

Japanese Patent No. 2973714

In the above-described conventional technique, the volume transition timing is detected by detecting a short-circuit occurrence timing every pulse cycle, and it is determined whether the short-circuit occurrence timing is an early region, a titrator region, or a late region with respect to the pulse cycle. And the pulse parameters are automatically adjusted.

However, even if the welding conditions are the same and the pulse parameters are optimum values, the volume transition timing has some variation. For this reason, it is likely that short-circuit occurrence timing becomes early or late. In the prior art, although the pulse parameter is set to the optimum value, there arises a case where the pulse parameter always changes in every pulse period due to this fluctuation. As a result, the volume transition state may become unstable.

Therefore, an object of the present invention is to provide a pulse arc welding output control method capable of stably performing automatic adjustment of pulse parameters even when the volume transition timing has a variation.

In order to solve the above-mentioned problems, the invention of claim 1 is a pulse arc welding output control method in which a welding wire is fed and a peak current during a peak period and a base current during a base period are repeated one pulse period As a result,

Detecting an occurrence timing of a short circuit between the welding wire and the base material at every pulse period, calculating an index indicating a distribution of the short-circuit occurrence time per unit time, and changing a pulse parameter in the waveform of the welding current based on the index And outputting the pulse signal to the pulse arc welding control unit.

The invention according to claim 2 is characterized in that the pulse period is divided in advance into an early region, a titrator region and a late region, the short-circuit occurrence time detected per unit time is classified into the early region, the titrator region or the late region, And the index is an area having the largest coefficient value. The output control method of pulse arc welding according to claim 1,

According to a third aspect of the present invention, the short circuit occurrence time is detected as a time with the end point of the peak period as a reference time point, the previous time point as a negative value and the subsequent time as a positive value, And the pulse arc welding output control method according to the present invention is an output control method of pulse arc welding according to claim 1,

In the prior art, the pulse parameters are automatically adjusted based on the occurrence time of the short circuit every pulse cycle. On the other hand, according to the present invention, pulse parameters are automatically adjusted based on values obtained by statistically processing short-circuit occurrence times for each unit time including a plurality of pulse cycles. Thus, in the present invention, even if the volume transition timing has a variation, automatic adjustment of the pulse parameters can be performed stably.

1 is a current / voltage waveform diagram for explaining a pulse arc welding output control method according to the first embodiment of the present invention.
2 is a block diagram of a welding power source for implementing a pulse arc welding output control method according to the first embodiment of the present invention.
3 is a current-voltage waveform diagram for explaining a pulse arc welding output control method according to Embodiment 2 of the present invention.
4 is a block diagram of a welding power source for implementing a pulse arc welding output control method according to Embodiment 2 of the present invention.
Fig. 5 is a general current / voltage waveform diagram in consumable electrode type pulse arc welding in the prior art.

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

[Embodiment 1]

In the invention of the first embodiment, the case where the arc length control method is the frequency modulation control and the pulse parameter to be subjected to the automatic adjustment is the peak period Tp will be described. Therefore, the peak current Ip and the base current Ib, which are other pulse parameters, are set to predetermined values, and the pulse period Tf is feedback-controlled.

1 is a current / voltage waveform diagram for explaining a pulse arc welding output control method according to the first embodiment of the present invention. 6A shows the waveform of the welding current Iw, and FIG. 6B shows the waveform of the welding voltage Vw. Since this figure is the same waveform as in Fig. 5 described above, the same description will not be repeated. Hereinafter, the automatic adjustment control of the peak period Tp will be described with reference to the drawings.

Step 1: The period from the time t1 at which the pulse cycle Tf starts to the time t2 at which the peak period Tp ends is set as the early region, the period from the time t2 to the time t22 when the predetermined period Tt elapses is set as the titration region, The period from time t22 to time t3, at which the next pulse cycle Tf starts, is defined in advance as a later area. The predetermined period Tt is set so that the peak current Ip falls and converges to the base current Ib. This predetermined period Tt is set by experiment in consideration of transient response and normal stability of the automatic adjustment control of the pulse parameters. (Peak period Tp) = 2.0 ms, the peak period (predetermined period Tt) of time t2 to t22 = 1.5 ms, and the late period of time t22 to t3 = 0.5 to 6.5 ms do.

Step 2: Determine occurrence of a short circuit. The occurrence of the short circuit is determined by lowering the welding voltage Vw to about 0 V as shown in (B) of Fig.

Step 3: Detect the occurrence time of the identified short circuit. Then, at the predetermined unit time, it is classified into the early region, the titrator region, or the late region according to the occurrence timing of the identified short circuit. The unit time is set in the range of about 0.1 to 5.0 seconds. Since the pulse frequency is in the range of about 100 to 250 Hz, 10 to 25 short circuits occur between 0.1 second and 500 to 1250 short circuits occur between 5.0 seconds. These short circuits are classified into the three regions according to the generation timing and counted.

Step 4: The region having the greatest coefficient value is identified for each unit time, the indicator Sd = 1 is output when the region is an early region, the indicator Sd = 2 is output when the region is the titrator region, And outputs the index Sd = 3. This index Sd indicates the distribution of the short-circuit occurrence timing. After the indicator Sd is output, the coefficients of each area are reset to zero.

Step 5: The peak period Tp is increased or decreased by a predetermined correction amount? D in accordance with the value of the indicator Sd for each unit time. The correction amount? D is a positive real number, and is set to about 0.05 to 0.3 ms. Since the correction amount? D corresponds to the gain of the automatic adjustment control of the pulse parameter, it is set to an appropriate value by experiment in consideration of transient response and normal stability. The increase and decrease are performed as follows. Tp (m) is a set value of the peak period at the present time, and Tp (m + 1) is a set value of the peak period after the increase / decrease. m is an integer of 1 or more.

Tp (m + 1) = Tp (m) -? D when Sd = 1

When Sd = 2, Tp (m + 1) = Tp (m)

When Sd = 3, Tp (m + 1) = Tp (m) +? D

When the index Sd = 1, the occurrence time of a short circuit occurring per unit time is the largest in the early region. In this case, the present set value of the peak period Tp is longer than the optimum value. Therefore, the present set value of the peak period Tp is made shorter by the correction amount? D.

When the indicator Sd = 2, the occurrence time of a short circuit occurring per unit time is the largest in the titrator region. In this case, the present set value of the peak period Tp is the optimum value. Therefore, the present set value of the peak period Tp is maintained as it is.

When the index Sd = 3, the occurrence time of a short circuit occurring per unit time is the largest in the latter region. In this case, the present set value of the peak period Tp is shorter than the optimum value. Therefore, the present set value of the peak period Tp is made longer by the correction amount? D.

The automatic adjustment control of the peak period Tp is performed by the above steps 1 to 5. In the above, the automatic adjustment control of the peak current Ip may be performed at the same time. In this case, the peak current Ip may be automatically adjusted according to the value of the index Sd. That is, when the index Sd = 1, the present set value of the peak current Ip is made smaller by a predetermined correction amount, and when Sd = 2, the current setting value is maintained.

In the case of the pulse width modulation control, the pulse period Tf and / or the peak current Ip may be automatically adjusted according to the value of the index Sd. Similarly, in the case of peak current modulation control, the peak period Tp and / or the pulse period Tf may be automatically adjusted according to the value of the index Sd.

Fig. 2 is a block diagram of a welding power source for carrying out the pulse arc welding output control method according to the first embodiment of the present invention described above with reference to Fig. 1; Hereinafter, each block will be described with reference to the drawings.

The power main circuit PM receives a commercial power source (not shown) such as three-phase 200V, and performs output control by inverter control in accordance with a drive signal Dv to be described later, and outputs a welding current Iw and a welding voltage Vw. Although not shown, the power main circuit PM includes a primary rectifier for rectifying a commercial power source, a capacitor for smoothing the rectified DC current, an inverter circuit for converting a smoothed direct current into a high frequency AC in accordance with the drive signal Dv, A high frequency transformer for reducing the voltage to a value suitable for arc welding, a secondary rectifier for rectifying the rectified high frequency AC, and a reactor for smoothing the rectified DC.

The welding wire 1 is wound around the wire reel 1a. The welding wire 1 is fed into 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 torch 4 and the base material 2 to perform welding. The welding current Iw is energized in the arc 3 and the welding voltage Vw is applied between the welding wire 1 and the base material 2. [

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

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

The short circuit determination circuit SA receives the welding voltage detection signal Vd, and determines a short circuit state based on the detected value, and outputs a short circuit determination signal Sa which becomes a high level. This circuit performs the operation of step 2 described above.

The index generation circuit SD performs the following processing by inputting the pulse period signal Tf, the peak period correction setting signal Tps and the short discrimination signal Sa to be described later, and outputs the index signal Sd.

1) Detect occurrence of a short circuit. The detection of the short circuit occurrence time is performed as follows. The time point at which the short-circuiting discrimination signal Sa changes to the high level is a period of time determined by the peak period correction setting signal Tps from the time point (time t1 in Fig. 1) when the pulse periodic signal Tf changes to the high level (From time t2 to time t22 in FIG. 1), it is determined that a short circuit has occurred in the titrator region, and the subsequent period (Time t22 to t3 in Fig. 1), it is determined that a short circuit has occurred in the latter area (the operation of steps 1 and 3 described above).

2) The identified short circuit is classified into an early region, a titrator region, or a late region according to the occurrence timing every predetermined unit time (the operation of Step 3 described above).

3) The region having the greatest coefficient value is discriminated for each unit time, the indicator signal Sd = 1 is output when the region is an early region, the indicator signal Sd = 2 is output when the region is the titrator region, , It outputs the indicator signal Sd = 3. The indicator signal Sd indicates the distribution of the short-circuit occurrence timing. After the indicator signal Sd is outputted, the coefficient of each area is reset to 0 (the operation of step 4 described above).

The peak period setting circuit TPR outputs a predetermined peak period setting signal Tpr. The peak period correction setting circuit TPS receives the peak period setting signal Tpr and the indicator signal Sd as inputs and sets the peak period setting signal Tpr as the initial value, Subtracts a predetermined correction amount DELTA D from the set value of the time point, adds 0 when Sd = 2, adds DELTA d when Sd = 3, and outputs a peak period correction setting signal Tps. That is, Tps = Tpr + [Sigma] (correction amount per unit time). This circuit performs the operation of step 5 described above.

The timer circuit TM receives the peak period correction setting signal Tps and the pulse period signal Tf and outputs a pulse signal having a high level for a period determined by the peak period correction setting signal Tps every time the pulse period signal Tf changes to the high level And outputs the timer signal Tm. Therefore, when this timer signal Tm is at a high level, it is a peak period, and when it is at a low level, it is a base period.

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 values of the peak period setting signal Tpr, the peak current setting signal Ipr, and the base current setting signal Ibr are set in accordance with welding conditions such as the material of the welding wire, the diameter, the item, the distance between the feeding chip and the parent material, And the optimum value is determined by experiment under this standard welding condition.

The switching circuit SW receives the timer signal Tm, the peak current setting signal Ipr, and the base current setting signal Ibr as input, and outputs the peak current setting signal Ipr as the current control setting signal Icr when the timer signal Tm is at the High level , And outputs the base current setting signal Ibr as the current control setting signal Icr when the level is low.

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

The welding current average value setting circuit IR outputs a predetermined welding current average value setting signal Ir. The feed rate setting circuit FR receives the welding current average value setting signal Ir and feeds the feed rate setting signal Fr corresponding to the value of the welding current average value setting signal Ir in accordance with a pre- And outputs it. The feed control circuit FC receives the feed rate setting signal Fr and outputs a feed control signal Fc for feeding the welding wire 1 at the feed rate determined by this value to the wire feed motor WM.

In the first embodiment described above, the pulse period is divided in advance into the early region, the titrator region, and the late region, and the short-circuit occurrence time detected per unit time is classified into the early region, the titrator region or the late region, And automatically adjusts the pulse parameter in the waveform of the welding current based on the index corresponding to the large area. In the prior art, the pulse parameters are automatically adjusted based on the occurrence time of the short circuit every pulse cycle. On the other hand, according to the present embodiment, the pulse parameters are automatically adjusted based on the cumulative value obtained by statistically processing the occurrence time of the short circuit every unit time including a plurality of pulse cycles. For this reason, in the present embodiment, it is possible to stably perform the automatic adjustment of the pulse parameters even if the volume transition timing has a variation.

[Embodiment 2]

3 is a current / voltage waveform diagram for explaining a pulse arc welding output control method according to the second embodiment of the present invention. 6A shows the waveform of the welding current Iw, and FIG. 6B shows the waveform of the welding voltage Vw. Since this figure is the same waveform as in Fig. 1 described above, the same description will not be repeated. Hereinafter, the automatic adjustment control of the peak period Tp will be described with reference to the drawings.

Step 10: Determine the occurrence of a short circuit. The occurrence of the short circuit is discriminated by reducing the welding voltage Vw to about 0 V (the same operation as in step 1 in Fig. 1), as shown in Fig.

Step 20: The generation time of the discriminated short is defined as a time point Td (time from time t2 to time t21) with the base time point at the end point of the peak period (time t2) as a negative value, . Then, an average value of each detected time Td is calculated at every predetermined unit time, and is output as an indicator Sd. This index Sd indicates the distribution of the short-circuit occurrence timing.

Step 30: The peak period Tp is increased or decreased by a predetermined correction amount? D in accordance with the value of the indicator Sd for each unit time. This correction amount? D is the same as in Fig. The increase and decrease are performed as follows. Tp (m) is the set value of the peak period at the present time, and Tp (m + 1) is the set value of the peak period after the increase / decrease. m is an integer of 1 or more. Tt is a predetermined period as in Fig.

Tp (m + 1) = Tp (m) -? D when Sd <

Tp (m + 1) = Tp (n) when 0 <

When Tt? Sd, Tp (m + 1) = Tp (m) +? D

When the index Sd < 0, the average value of the occurrence time of the short circuit generated per unit time exists in the early region defined in Fig. 1. In this case, the present set value of the peak period Tp is longer than the optimum value. Therefore, the present set value of the peak period Tp is made shorter by the correction amount? D.

When the index Sd is 0? Sd < Tt, the average value of the occurrence time of the short circuit generated per unit time exists in the titrator region defined in Fig. 1. In this case, the present set value of the peak period Tp is the optimum value. Therefore, the present set value of the peak period Tp is maintained as it is.

When the index Sd &gt; Tt, the average value of the occurrence time of the short circuit generated per unit time is present in the late region defined in Fig. 1. In this case, the present set value of the peak period Tp is shorter than the optimum value. Therefore, the present set value of the peak period Tp is made longer by the correction amount? D.

The automatic adjustment control of the peak period Tp is performed by the above steps 10 to 30. In the above, the automatic adjustment control of the peak current Ip may be performed at the same time. In this case, the peak current Ip may be automatically adjusted according to the value of the index Sd. In the case of the pulse width modulation control, the pulse period Tf and / or the peak current Ip may be automatically adjusted according to the value of the index Sd. Similarly, in the case of peak current modulation control, the peak period Tp and / or the pulse period Tf may be automatically adjusted according to the value of the index Sd.

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 assigned to the same blocks, and description thereof is not repeated. In the drawing, the index generating circuit SD shown in FIG. 2 is replaced with a second index generating circuit SD2, and the peak period correction setting circuit TPS shown in FIG. 2 is replaced with a second peak period correction setting circuit TPS2. Hereinafter, these blocks will be described with reference to the drawings.

The second indicator generating circuit SD2 receives the pulse period signal Tf, the peak period correction setting signal Tps and the short discrimination signal Sa, performs the following processing, and outputs the indicator signal Sd.

1) Detect occurrence of a short circuit. The detection of the short circuit occurrence time is performed as follows. The time Ta from when the pulse period signal Tf changes to High level (time t1 in Fig. 3) to when the short discrimination signal Sa changes to High level (time t21 in Fig. 3) is measured. Then, the time Td = Ta-Tps indicating the occurrence of the short circuit is calculated (the operation of step 20 described above).

2) calculates an average value of each time Td at the detected short-circuit occurrence timing every predetermined unit time, and outputs it as the indicator signal Sd (the operation of step 20 described above).

The second peak period correction setting circuit TPS2 receives the peak period setting signal Tpr and the indicator signal Sd as input, sets the value of the peak period setting signal Tpr as an initial value, and when the indicator signal Sd <0 Subtracts a predetermined correction amount DELTA D from the current set point value, adds 0 when 0 < = Sd &lt; Tt and adds DELTA d when Tt &lt; = Sd, and outputs a peak period correction setting signal Tps. Tt is a predetermined period. That is, Tps = Tpr + [Sigma] (correction amount per unit time). This circuit performs the operation of step 30 described above.

In the second embodiment described above, the short-circuit occurrence time is detected as a time when the end time of the peak period is set as a reference time point, the former is regarded as a negative value, the subsequent time is regarded as a positive value, And the pulse parameters in the waveform of the welding current are changed to automatically adjust. In the prior art, the pulse parameters are automatically adjusted based on the occurrence time of the short circuit every pulse cycle. On the other hand, according to the present embodiment, the pulse parameters are automatically adjusted based on the average value of the time when the short-circuit occurrence time is statistically processed every unit time including a plurality of pulse cycles. Thus, in this embodiment, even if the volume transition timing has a variation, automatic adjustment of the pulse parameters can be performed stably.

1: welding wire
1a: Wire reel
2: base material
3: arc
4: welding torch
5: Feed roll
Dv: drive signal
EI: Current error amplifying circuit
Ei: current error amplified signal
EV: voltage error amplifier circuit
Ev: Voltage error amplified signal
FC: feed control circuit
Fc: feed control signal
FR: feed rate setting circuit
Fr: feed rate setting signal
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
PM: Power main circuit
SA: Short circuit discrimination circuit
Sa: Paragraph discrimination signal
SD: Indicator generation circuit
Sd: indicator (signal)
SD2: Second indicator generation circuit
SW: switching circuit
Ta: Time from the start of the pulse cycle
Tb: Base period
Td: time from the end of the peak period
Tf: Pulse period (signal)
TM: Timer circuit
Tm: Timer signal
Tp: peak period
TPR: peak period setting circuit
Tpr: peak period setting signal
TPS: peak period correction circuit
Tps: Peak period correction setting signal
TPS2: second peak period correction setting circuit
Tt: a predetermined period
VAV: welding voltage average value calculating circuit
Vav: Welding voltage mean 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 signal
Vw: welding voltage
WM: Wire feed motor
Δd: Amount to be corrected

Claims (3)

A pulse arc welding output control method in which a welding wire is fed (fed), and a peak current during a peak period and a base current during a base period are repeated one pulse cycle,
And a control unit that detects an occurrence time of a short circuit between the welding wire and the base material at every pulse period and calculates an index indicating a distribution of the short circuit occurrence time per unit time and changes a pulse parameter in the waveform of the welding current based on the index Wherein the pulse arc welding is performed by a pulse arc welding method. The method according to claim 1,
The pulse period is divided in advance into an early region, a titrator region, and a late region, and the short-circuit occurrence time detected per unit time is classified into the early region, the titrator region, or the late region, Value of the pulse arc welding is the largest. The method according to claim 1,
Wherein the short circuit occurrence time is detected as a time with the end point of the peak period as a reference point and the previous point as a negative value and thereafter as a positive value, Time of the pulse arc welding.

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