JP2004298924A - Method for controlling feeding of wire in arc welding accompanied with short circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the stability of a welding state in a method for controlling feeding of wire in arc welding accompanied with short circuit with which a welding wire is advancedly fed to a base material during arc time and the welding wire is retreatedly fed to the direction leaving from the base material during short circuit time. <P>SOLUTION: In the control method for feeding the wire in arc welding accompanied with the short circuit, the advanced feeding is succeeded and also, the welding current Iw is increased until passing a preset long term short circuit distinguishing time Tt from the time point when the short circuit is generated, and after passing the long term short circuit distinguishing time Tt, the advanced feeding is changed over to the retreated feeding and also, the welding current Iw is decreased, and when the arc is regenerated (t5) by leaving the tip part of the wire from the base material with the retreated feeding, this feeding is again changed over to the advanced feeding and also, the welding current Iw is increased to a value according to the feeding speed of the advanced feeding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a feed control method during a short circuit period in arc welding involving a short circuit.
[0002]
[Prior art]
FIG. 7 is an output waveform diagram showing a conventional feed control method for arc welding with a short circuit. (A) shows the welding voltage Vw, (B) shows the welding current Iw, (C) shows the feed speed setting signal Fr, and (D) shows the feed speed Fs at the wire tip. Shows the time change. The above-described arc welding with a short circuit includes short-circuit transfer welding, globule transfer welding with a short circuit, pulse arc welding with a short circuit, and the like. Hereinafter, short-circuit transfer welding, which is a typical example of arc welding involving short-circuiting, will be described as an example, as shown in FIG.
[0003]
In the short-circuit transfer welding, a short-circuit period Ts from time t1 to t2 and an arc period Ta from time t2 to t3 are alternately repeated. As shown in FIG. 3A, the welding voltage Vw has a short-circuit voltage value of about several V during the short-circuit period Ts, and has an arc voltage value of about 15 to 40 V during the arc period Ta. Also, as shown in FIG. 3B, the welding current Iw gradually increases during the short-circuit period Ts to promote the release of the short-circuit, and has a current waveform determined by the arc load during the arc period Ta. Usually, by controlling the current waveform during the short-circuit period Ts, the droplet is smoothly transferred, and the short-circuit is released at an appropriate time to re-generate the arc. On the other hand, during the arc period Ta, constant voltage control is performed to maintain the arc length at an appropriate value, so that the welding current Iw changes depending on the arc load. As shown in FIG. 3C, the feed speed setting signal Fr is set to a predetermined constant value, and the feed speed Fs also becomes a constant value as shown in FIG.
[0004]
By the above-described short-circuit current control and arc length control, the short period Ts is substantially distributed in the range of 3 to 7 ms, as shown at times t1 to t5. However, as shown at times t5 to t6, a long-term short circuit exceeding about 10 ms sometimes occurs. This is because the arc length fluctuates due to various disturbances such as fluctuations in the feed rate, irregular movement of the molten pool and droplets, and fluctuations in the torch height (distance between tip and base material), and the wire tip is not sufficiently sharp. This is because a short circuit occurs in a state where the metal is not melted. In this state, it is necessary to apply a large current for a long time to forcibly blow the tip of the wire by Joule heat. When such a long-term short circuit occurs, even if an arc is regenerated by fusing, large-sized spatters are generated with the fusing, and the arc state becomes unstable. In addition, the distance between the tip of the wire and the base material may be increased during fusing, and in such a case, an arc break occurs as shown at time t6.
[0005]
As described above, the short-circuit period Ts usually ends with a short-circuit in most cases, but occasionally leads to a long-term short-circuit due to disturbance. Even if a long-term short-circuit occurs, current control is performed to release the short-circuit as soon as possible, but it is not possible to completely prevent the occurrence of spatter and the breakage of the arc.
[0006]
In order to solve the above-mentioned problem, a method has been proposed in which the feeding direction of the welding wire is reversed during the short-circuit period and the welding wire is fed backward in a direction away from the base material (for example, see Patent Document 1). Hereinafter, another conventional technique will be described.
[0007]
FIG. 8 is an output waveform diagram of the related art in which the sheet is fed backward during the short circuit period. (A) shows the welding voltage Vw, (B) shows the welding current Iw, (C) shows the feed speed setting signal Fr, and (D) shows the feed speed Fs at the wire tip. Shows the time change. Hereinafter, description will be made with reference to FIG.
[0008]
During the short-circuit period Ts from the time t1 to t2, the feed speed setting signal Fr becomes a negative backward feed speed set value Frr as shown in FIG. The feeding speed Fs is reduced from time t1 with a slope due to inertia. However, as described above, since the time of the short circuit is usually about 3 to 7 ms, even if a pulse motor or a servo motor having excellent transient characteristics is used, the feeding direction is reversed during this time and the backward feeding is performed. It doesn't even pay. Subsequently, during the arc period Ta from the time t2 to the time t3, the feed speed setting signal Fr becomes a positive forward feed speed set value Ffr as shown in FIG. As shown in (2), from time t2, the vehicle accelerates with a slope due to inertia and reaches the forward feed speed Ffs. As described above, in the normal short circuit, only the deceleration and acceleration of the feed speed Fs are performed, and there is no benefit from this. That is, as described above with reference to FIG. 7, stable droplet transfer and short circuit release can be performed by short-circuit current control in a state in which the feed speed is forwardly fed at a constant value, so that the feed speed is changed. No need. On the contrary, when the feed speed is unnecessarily decelerated and accelerated, the feed speed becomes the same as the change in the feed speed due to disturbance, and there is a disadvantage that the welding state is rather unstable.
[0009]
On the other hand, the long-term short circuit between times t5 and t8 is as follows. At time t5, the feed speed setting signal Fr is switched to the reverse feed speed set value Frr as shown in FIG. 9C, and the feed speed Fs is a slope due to inertia as shown in FIG. Slow down. Then, at time t6, the feed motor starts to rotate in the reverse direction, but until the time t7 when the play due to the bending of the welding wire in the feed path from the feed motor to the base metal is fed backward, the wire tip ends. Is not backed off and remains stopped. At time t7, when the backward feed of the play ends, the wire tip is retreated, and at time t8, the wire tip separates from the base material and an arc is generated again. When the arc re-occurs, the feed speed setting signal Fr is switched to the forward feed speed set value Ffr at time t8 as shown in FIG. 9C, and the feed speed is set as shown in FIG. Fs switches from reverse feed to forward feed after a delay time similar to that described above.
[0010]
As described above, since the short-circuit period is long in the long-term short circuit, the welding wire can be switched to the backward feeding during the short circuit period. For this reason, a long-term short circuit can be reliably released and an arc can be regenerated. However, as shown in FIG. 5B, the current value when the arc is regenerated at the time t8 is very large, so that large spatters are generated when the arc is regenerated. Furthermore, since the arc length immediately after time t8 is of course very short, if a large current flows in this state, a large arc force may deform the molten pool and the droplet and return to a short circuit state again. Thus, while there is a benefit in that long term shorts can be cleared, problems remain.
[0011]
[Patent Document 1]
JP-B-48-20688 [0012]
[Problems to be solved by the invention]
As described above, in the general prior art in which the feeding speed is a constant value, a good droplet transfer and short circuit release can be performed by a short circuit current control during a normal short circuit. There are problems such as generation of spatter. On the other hand, in another conventional technique of feeding back to a short-circuit engine, the feeding speed is usually unnecessarily reduced and accelerated during a short-circuit, so that the welding state tends to be unstable. Further, in the case of a long-term short circuit, it is possible to reliably release the short circuit by retreating and re-generate an arc, but there is a problem of occurrence of spatter and re-short circuit. Therefore, there is a problem in both the prior arts.
[0013]
Therefore, in the present invention, in arc welding involving a short circuit, it is possible to perform good droplet transfer during a normal short circuit and a long-term short circuit, and to perform a good short circuit release without arc break, spatter and re-short circuit. To provide a feeding control method.
[0014]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 includes a short circuit that feeds a welding wire forward to a base material during an arc period, and feeds back a welding wire backward in a direction away from the base material during a short circuit period. In the accompanying arc welding feed control method,
The forward feeding is continued and the welding current is increased until the predetermined long-term short-circuit determination time elapses from the time when the short-circuit occurs, and the welding current is increased after the long-term short-circuit determination time elapses. The welding current is reduced, and when the wire retreats from the base metal due to the backward feeding and the arc reoccurs, the mode is switched again to the forward feeding and the welding current is increased to a value corresponding to the feeding speed of the forward feeding. This is a feed control method for arc welding with a short circuit characterized by causing a short circuit.
[0015]
Further, the invention according to claim 2 is characterized in that after the long-term short-circuit determination time has elapsed, switching to the backward feeding is performed, and after a predetermined current decrease delay time has elapsed from the time when the long-term short-circuit determination time has elapsed, the welding current is reduced. 2. The feed control method for arc welding with a short circuit according to claim 1, wherein
[0016]
Further, the invention according to claim 3 is characterized in that the backward feeding is continued until the predetermined backward feeding continuation time elapses from the time when the arc re-occurs, and the welding current is kept reduced, and The arc with a short circuit according to claim 1 or 2, wherein after the feed duration time has elapsed, the welding is switched back to the forward feed and the welding current is increased to a value corresponding to the feed speed of the forward feed. This is a feed control method for welding.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
[Embodiment 1]
FIG. 1 is an output waveform diagram showing a feed control method for arc welding with a short circuit according to Embodiment 1 of the present invention. (A) shows the welding voltage Vw, (B) shows the welding current Iw, (C) shows the feed speed setting signal Fr, and (D) shows the feed speed Fs at the wire tip. Shows the time change. Hereinafter, description will be made with reference to FIG.
[0019]
During the short-circuit period Ts from the time t1 to t2, the short-circuit period is equal to or shorter than the predetermined long-term short-circuit determination time Tt. Therefore, as shown in FIG. Ffr is maintained, and the feed speed Fs is fed at the forward feed speed Ffs, as shown in FIG. During the subsequent arc period Ta from time t2 to time t3, the forward feed speed set value Ffr remains at the above-mentioned forward feed speed set value Ffr, as shown in FIG. Are fed at the above-mentioned forward feed speed Ffs. That is, a normal value of forward feeding is maintained during a short circuit.
[0020]
Until time t4 when a short circuit occurs at time t3 and the long-term short circuit determination time Tt elapses, the feed speed setting signal Fr remains at the forward feed speed set value Ffr, as shown in FIG. As shown in FIG. (D), the feed speed Fs remains at the forward feed speed Ffs. When the long-term short-circuit determination time Tt has elapsed at time t4, the feed speed setting signal Fr switches to the reverse feed speed set value Frr, as shown in FIG. Meanwhile, the feeding speed Fs is reduced by a slope due to inertia. At the same time, the welding current Iw is reduced to a low value from time t4, as shown in FIG.
[0021]
As shown in FIG. 3D, the feed speed Fs is reduced to 0 once, and remains at 0 because the feed speed is the feed speed of the wire tip until the play portion is fed backward. The wire is fed backward, and at time t5, the tip of the wire separates from the base material, the short circuit is released, and an arc is generated again. Since the current value at the time of the arc re-generation is a low value as shown in FIG. 7B, almost no spatter occurs, and the arc force is weak, so that no re-short-circuit occurs. Therefore, good long-term short circuit release can be performed.
[0022]
When the arc re-occurs at time t5, the feed speed setting signal Ffr switches to the forward feed speed set value Ffr, as shown in FIG. 9C, and the feed speed is set as shown in FIG. Fs is fed at a forward feed speed Ffs through deceleration, stop, and reversal from reverse feed. At the same time, as shown in FIG. 3B, the welding current Iw increases to a value corresponding to the forward feed speed Ffs determined by the constant voltage characteristics of the welding power supply device and the arc load.
[0023]
As described above, in the first embodiment, during a normal short circuit, the forward feeding of a constant value is continued, and the transfer of the droplet and the release of the short circuit are performed by the short circuit current control. On the other hand, in the case of a long-term short-circuit, the backward feeding is started after the elapse of the predetermined long-term short-circuit determination time Tt, and the welding current is reduced so that a good long-term short-circuit without arc break, spatter, and re-short can be released. It can be carried out.
[0024]
FIG. 2 is a block diagram of the welding power supply device according to Embodiment 1 described above. Hereinafter, each circuit will be described with reference to FIG.
[0025]
The power supply main circuit MC receives a commercial AC power supply (three-phase 200 V or the like) as input, performs output control such as inverter control and thyristor phase control in accordance with a drive signal Dv described later, and outputs a welding voltage Vw and a welding current Iw suitable for welding. Output. The welding wire 1 is fed through the welding torch 4 by the rotation of the feed roll 5 directly connected to the wire feed motor WM, and an arc 3 is generated between the welding wire 1 and the base material 2.
[0026]
The voltage detection circuit VD detects the above welding voltage Vw and outputs a voltage detection signal Vd. The short-circuit determination circuit SD receives the above-described voltage detection signal Vd to determine a short-circuit or an arc, and outputs a short-circuit determination signal Sd having a high level during the short-circuit period. The long-term short-circuit discrimination circuit TT outputs a long-term short-circuit discrimination signal Tt in which the short-circuit discrimination signal Sd is ON-delayed by a predetermined long-term short-circuit discrimination time. Therefore, the long-term short-circuit determination signal Tt is a signal that becomes High level only during the period from the time t4 to the time t5 in FIG. The reverse feed speed setting circuit FRR outputs a desired reverse feed speed setting signal Frr. The forward feed speed setting circuit FFR outputs a desired forward feed speed setting signal Ffr. The feed speed setting switching circuit SF switches to the b side when the long-term short-circuit determination signal Tt is at the Low level, outputs the forward feed speed setting signal Ffr as the feed control setting signal Fcr, and outputs the High level. In this case, the reverse feed speed setting signal Frr is output as the feed control setting signal Fr. The feed control circuit FC outputs a feed control signal Fc for feeding the welding wire to the wire feed motor WM according to the feed speed setting signal Fr. Therefore, during the period from the time t4 to the time t5 in FIG. 1 described above, the feed speed setting signal Fr becomes the reverse feed speed setting signal Frr, and the welding wire 1 is fed backward.
[0027]
The short-circuit current setting circuit ISR outputs a predetermined short-circuit current setting signal Isr for setting a current change during the short-circuit period. The decreasing current setting circuit IMR outputs a predetermined decreasing current setting signal Imr. Here, the short-circuit current setting signal Isr is a signal for setting a change in the short-circuit current in each of the periods of time t1 to t2 and time t3 to t4, as described above with reference to FIG. On the other hand, the above-described reduced current setting signal Imr is a signal for setting the reduced current Im in the period from the time t4 to the time t5, as described above with reference to FIG. The current setting switching circuit SI switches to the b side when the long-term short-circuit discrimination signal Tt is at a low level, outputs the short-circuit current setting signal Isr as a current control setting signal Icr, and when the high level is at a high level. , And outputs the reduced current setting signal Imr as the current control setting signal Icr. Therefore, during the period from time t4 to time t5 in FIG. 1 described above, the current control setting signal Icr becomes the decreasing current setting signal Imr, and the welding current Iw decreases. The arc voltage setting circuit VAR outputs an arc voltage setting signal Var of a desired value for setting an arc voltage during an arc period.
[0028]
The current detection circuit ID detects the above welding current Iw and outputs a current detection signal Id. The current error amplifier EI amplifies an error between the current control setting signal Icr and the current detection signal Id, and outputs a current error amplified signal Ei. The voltage error amplification circuit EV amplifies the error between the arc voltage setting signal Var and the voltage detection signal Vd, and outputs a voltage error amplification signal Ev. When the short-circuit determination signal Sd is at the low level (arc period), the external characteristic switching circuit SP switches to the b side, outputs the voltage error amplification signal Ev as the error amplification signal Ea, and outputs the high level (short period). In the case of ()), the current is switched to the a side, and the above-described current error amplification signal Ei is output as the error amplification signal Ea. Therefore, constant voltage control is performed during the arc period, and constant current control is performed during the short circuit period. The drive circuit DV outputs a drive signal Dv for driving an inverter circuit or the like in accordance with the error amplification signal Ea.
[0029]
[Embodiment 2]
FIG. 3 is an output waveform diagram showing a feed control method for arc welding with a short circuit according to Embodiment 2 of the present invention. (A) shows the welding voltage Vw, (B) shows the welding current Iw, (C) shows the feed speed setting signal Fr, and (D) shows the feed speed Fs at the wire tip. Shows the time change. In the figure, since the operation is the same as that of FIG. 1 described above except for the current decrease delay period Tid from time t4 to t41, the description is omitted. Hereinafter, the operation of the current decrease delay period Tid will be described with reference to FIG.
[0030]
When the long-term short circuit determination time Tt elapses at time t4, the feed speed setting signal Fr is switched to the reverse feed speed set value Frr as shown in FIG. Initiate reverse feed. This operation is the same as in FIG. 1 described above. However, as shown in FIG. 5B, the welding current Iw is not decreased from time t4 but is decreased from time t41. This is different from FIG. 1 described above. The time t41 is a time when a predetermined current decrease delay time Tid has elapsed from the time t4. The current decrease delay time Tid is, as shown in FIG. 3D, such that the slope due to inertia ends after the backward feeding starts and the feeding motor starts reverse rotation. Set to. The reason for delaying the timing of the current decrease in this way is as follows. That is, the reason for reducing the current is to reduce the current value at the time of the arc re-occurrence at time t5 to suppress the occurrence of spatter and re-short circuit. Therefore, even when the feed motor starts reverse rotation corresponding to the backward feed at time t41, the wire tip remains stopped until the play due to the bending of the welding wire in the feed path is backward fed as described above. It is not sent back. In other words, since the wire tip separates from the base material shortly after time t41 and the arc is regenerated, the current value at the time of arc re-generation can be reduced even if the current is reduced at time t41, and the above-described effect is obtained. Does not impair. In addition, since the time during which the current is reduced can be made shorter than that in FIG. 1 described above, the time required to lower the temperature of the molten pool is shortened, and the effect on the bead appearance is minimized. Can be
[0031]
FIG. 4 is a block diagram of the welding power supply device according to Embodiment 2 described above. In the figure, the same circuits as those in FIG. 2 described above are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, a circuit indicated by a dotted line different from FIG. 2 will be described.
[0032]
The current decrease delay circuit TID receives the long-term short-circuit determination signal Tt and outputs a current decrease delay signal Tid that is ON-delayed by a predetermined current decrease delay time. Therefore, the current decrease delay signal Tid is a signal that becomes High level only during the period from the time t4 to the time t41 in FIG. During this period, the current control setting signal Icr becomes the decreasing current setting signal Imr, and the welding current Iw decreases.
[0033]
[Embodiment 3]
FIG. 5 is an output waveform diagram showing a feed control method for arc welding with a short circuit according to Embodiment 3 of the present invention. (A) shows the welding voltage Vw, (B) shows the welding current Iw, (C) shows the feed speed setting signal Fr, and (D) shows the feed speed Fs at the wire tip. Shows the time change. In the figure, the operation is the same as that of FIG. 3 described above except for the operation of the backward feed continuation time Trc from the time t5 to the time t51, and the description thereof is omitted. Hereinafter, the operation during the backward feeding continuation time Trc will be described with reference to FIG.
[0034]
At time t5, when the wire tip separates from the base material due to the backward feeding and the arc reoccurs, the time (t) from time t5 to time t51 at which the predetermined backward feeding continuation time Trc elapses is the same as FIG. As shown in FIG. 7, the feed speed setting signal Fr is kept at the reverse feed speed set value Frr, and the reverse feed is continued as shown in FIG. Similarly, as shown in FIG. 3B, the welding current Iw is maintained in a reduced state.
[0035]
As described above, the reason why the backward feeding is continued for a short time after the occurrence of the arc and the current is maintained at a reduced level is as follows. That is, the above-mentioned backward feeding continuation time Trc is for raising the arc length (the distance between the wire tip and the base material) to the steady arc length by the backward feeding. As a result, at time t51, after switching to forward feeding, the arc length quickly converges to a steady arc length and a stable arc state is established. Therefore, the backward feeding continuation time Trc is set as a time for raising the arc length to the steady arc length. The reason why the current is reduced during the pulling is to reduce the error of the pulling distance due to the melting by reducing the melting of the wire tip during this period, and to accurately perform the pulling to the steady arc length. .
[0036]
FIG. 6 is a block diagram of the welding power supply device according to Embodiment 3 described above. In the figure, the same circuits as those in FIG. 4 described above are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, a circuit indicated by a dotted line different from FIG. 4 will be described.
[0037]
The reverse feed continuation circuit TRC receives the long-term short-circuit determination signal Tt, performs an off-delay by a predetermined reverse feed continuation time, and outputs a reverse feed continuation signal Trc. This signal is at the High level during the period from time t4 to time t51 in FIG. The current decrease delay circuit TID receives the backward feed continuation signal Trc, performs on-delay for a predetermined current decrease delay time, and outputs a current decrease delay signal Tid. This signal is at the high level during the period from time t41 to t61 in FIG. The OR circuit OR calculates the logical sum of the short circuit determination signal Sd and the backward feeding continuation signal Trc, and outputs a logical sum signal Or. This signal is at the high level during the period from time t3 to t51 in FIG.
[0038]
In the above-described third embodiment, the case where the backward feeding continuation time is added to the second embodiment has been described. The same applies to the case where the backward feeding continuation time is added to the first embodiment. That is, the current decrease delay time from time t4 to time t41 in FIG. 5 described above may be deleted. In addition, the current reduction delay circuit TID in FIG. 6 described above may be deleted.
[0039]
In the first to third embodiments described above, the case of short-circuit transfer welding has been described. However, the present invention relating to the short-circuit period can be similarly applied to globule transfer welding with short-circuit and pulse arc welding with short-circuit. . That is, the present invention includes all arc welding with a short circuit.
[0040]
【The invention's effect】
According to the feed control method for arc welding with a short circuit according to the first aspect, the reverse feed can be performed only during a long-term short circuit, and the current value at the time of re-arc occurrence can be reduced. Play. First, since a backward feed is not performed during a normal short circuit, the transfer of droplets and the short circuit can be satisfactorily performed without unnecessary deceleration and acceleration applied to the feed speed. Furthermore, in the case of a long-term short circuit, it is possible to satisfactorily release the long-term short circuit without causing arc breaking, spattering, and re-short-circuiting.
[0041]
According to the feed control method for arc welding with a short circuit according to the second aspect, by delaying the timing of decreasing the current, in addition to the above-described effect, the time for lowering the temperature of the molten pool is shortened. Impact on the system can be minimized.
[0042]
According to the feed control method for arc welding with a short circuit according to claim 3, in addition to the above-described effect, the arc length can be quickly increased after the re-arc occurs by adding the backward feed continuation time after the re-arc occurs. Can be increased to the steady arc length, so that the steady arc state can be quickly converged.
[Brief description of the drawings]
FIG. 1 is an output waveform diagram showing a feed control method for arc welding with a short circuit according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram of the welding power supply device according to Embodiment 1 of the present invention.
FIG. 3 is an output waveform diagram showing a feed control method for arc welding with a short circuit according to Embodiment 2 of the present invention.
FIG. 4 is a block diagram of a welding power supply device according to Embodiment 2 of the present invention.
FIG. 5 is an output waveform diagram showing a feed control method for arc welding with a short circuit according to Embodiment 3 of the present invention.
FIG. 6 is a block diagram of a welding power supply device according to Embodiment 3 of the present invention.
FIG. 7 is an output waveform diagram showing a feed control method for arc welding with a short circuit in Prior Art 1.
FIG. 8 is an output waveform diagram showing a feed control method for arc welding with a short circuit in Prior Art 2.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 welding wire 2 base material 3 arc 4 welding torch 5 feed roll DV drive circuit Dv drive signal Ea error amplification signal EI current error amplification circuit Ei current error amplification signal EV voltage error amplification circuit Ev voltage error amplification signal FC transmission control circuit Fc feed control signal FFR forward feed speed setting circuit Ffr forward feed speed setting (value / signal)
Ffs Forward feed speed Fr Feed speed setting signal FRR Reverse feed speed setting circuit Frr Reverse feed speed setting (value / signal)
Fs Feeding speed Icr Current control setting signal ID Current detection circuit Id Current detection signal Im Decrease current value IMR Decrease current setting circuit Imr Decrease current setting signal ISR Short circuit current setting circuit Isr Short circuit current setting signal Iw Welding current MC Power supply main circuit OR logic Sum circuit Or Logical sum signal SD Short circuit discrimination circuit Sd Short circuit discrimination signal SF Feeding speed setting switching circuit SI Current setting switching circuit SP External characteristic switching circuit Ta Arc period TID Current decrease delay circuit Tid Current decrease delay (time / signal)
TRC Reverse feed continuation circuit Trc Reverse feed continuation (time / signal)
Ts Short-circuit period TT Long-term short-circuit determination circuit Tt Long-term short-circuit determination (time / signal)
VAR Arc voltage setting circuit Var Arc voltage setting signal VD Voltage detection circuit Vd Voltage detection signal Vw Welding voltage WM Wire feed motor

Claims (3)

In the feed control method of arc welding with a short circuit that feeds the welding wire forward to the base material during the arc period and retracts the welding wire away from the base material during the short circuit period,
The forward feeding is continued and the welding current is increased until the predetermined long-term short-circuit determination time elapses from the time when the short-circuit occurs, and the welding current is increased after the long-term short-circuit determination time elapses. The welding current is reduced, and when the wire retreats from the base metal due to the backward feeding and the arc reoccurs, the mode is switched again to the forward feeding and the welding current is increased to a value corresponding to the feeding speed of the forward feeding. A feed control method for arc welding with a short circuit characterized by causing a short circuit. 2. The method according to claim 1, wherein after the long-term short-circuit determination time has elapsed, the feeding is switched to the reverse feeding, and the welding current is reduced after a predetermined current decrease delay time has elapsed from the time when the long-term short-circuit determination time has elapsed. Feed control method for arc welding with short circuit. Until the predetermined backward feeding continuation time elapses from the time when the arc re-occurs, the backward feeding is continued and the welding current is kept reduced, and after the backward feeding continuation time has elapsed, The feed control method for arc welding with a short circuit according to claim 1 or 2, wherein the mode is switched to the forward feed again, and the welding current is increased to a value corresponding to the feed speed of the forward feed.

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