JP7429598B2 - arc welding power supply - Google Patents

Description

The present invention relates to a consumable electrode type arc welding power source that can obtain good arc startability.

In the invention of Patent Document 1, when the welding current starts flowing at the start of welding, the voltage setting signal is set to a start voltage setting value that is larger than the steady voltage setting value during the first period, and during the following steady period. In the arc start control method for consumable electrode arc welding in which the voltage setting signal is set to the steady voltage setting value and welding current is applied by constant voltage control, the welding voltage detection value increases and becomes equal to the starting voltage setting value. At that point, the first period ends. In the invention of Patent Document 1, the first period ends after the arc length (welding voltage detection value) always reaches the target arc length (start voltage setting value). For this reason, it is stated that after the arc is generated, appropriate heat input to the welding wire and base metal is performed, and good arc startability can be obtained.

Japanese Patent Application Publication No. 2013-132658

In the prior art described above, a first period is provided in which the voltage setting value is a starting voltage setting value larger than the steady voltage setting value. During this first period, the arc length is longer than the steady arc length during the steady period. For this reason, the arc length overshoots during the first period, undershoots when transitioning to the steady period, and then converges to the steady arc length. Depending on the welding conditions such as the transient characteristics of the feeding speed, the distance between the power feeding tip and the base metal, and the material of the welding wire, the above-mentioned overshoot and undershoot may become large, resulting in a problem that the welding quality at the welding start point will deteriorate. .

Therefore, an object of the present invention is to provide an arc welding power source that can always obtain good welding quality at the welding start point without being affected by various welding conditions.

In order to solve the above-mentioned problem, the invention of claim 1 provides that when the welding current starts flowing at the start of welding, the voltage setting signal is set to a start voltage setting value larger than the steady voltage setting value during the first period. In an arc start control method for consumable electrode arc welding, the welding current is applied by constant voltage control by setting the voltage setting signal to the steady voltage setting value during the following steady period,
an output control unit that controls the welding voltage value to the value of the voltage setting signal;
a feed control unit that controls the feed speed of the welding wire to the value of the feed speed setting signal;
In an arc welding power source equipped with
a period setting unit that outputs a period signal that transitions over time to a first period, a second period, and a steady period when the welding current starts flowing;
When the period signal is in the first period, it is a first voltage setting value, when the period signal is in the second period, it is a second voltage setting value, and when the period signal is in the steady period, it is a steady voltage setting value. a voltage setting unit that outputs the voltage setting signal, which is a voltage setting value and satisfies the first voltage setting value<the second voltage setting value<the steady voltage setting value;
When the period signal is in the first period, it becomes the first feeding speed setting value; when the period signal is in the second period, it becomes the second feeding speed setting value; and when the period signal is in the steady period, it becomes the second feeding speed setting value. In some cases, the feed speed setting value becomes the steady feed speed setting value, and the feed speed outputs the feed speed setting signal such that the first feed speed setting value<the second feed speed setting value<the steady feed speed setting value. comprising a setting section;
The period setting unit is configured to shift to the second period when the welding voltage value increases during the first period and becomes equal to the first voltage setting value, and to increase the welding voltage value during the second period. When the voltage becomes equal to the second voltage setting value, the steady-state period begins;
This is an arc welding power source characterized by the following.

The invention of claim 2 is:
The period setting unit is configured to shift to the second period when a first predetermined period elapses after the welding voltage value increases during the first period and becomes equal to the first voltage setting value, and to set the welding voltage value to the second period. When a second predetermined period elapses after the welding voltage value increases during the welding voltage value and becomes equal to the second voltage setting value, the welding voltage value shifts to the steady period.
The arc welding power source according to claim 1, characterized in that:

The invention of claim 3 is:
The period setting unit transitions to the second period when the elapsed time of the first period becomes a first upper limit time or more, and transitions to the steady period when the elapsed time of the second period becomes more than a second upper limit time. ,
The arc welding power source according to claim 1 or 2, characterized in that:

According to the present invention, it is possible to always obtain good welding quality at the welding start part without being affected by various welding conditions.

FIG. 1 is a block diagram of an arc welding power source according to an embodiment of the present invention. 2 is a timing chart of each signal in the arc welding power source of FIG. 1. FIG.

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

FIG. 1 is a block diagram of an arc welding power source according to an embodiment of the present invention. Each block will be explained below with reference to the same figure.

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

The welding wire 1 is fed through the welding torch 4 by rotation of a feed roll 5 coupled to a feed motor WM, and an arc 3 is generated between the welding wire 1 and the base metal 2 to perform welding. A welding voltage Vw is applied between the welding wire 1 and the base metal 2, and a welding current Iw is applied. Welding torch 4 is mounted on a robot (not shown).

Voltage detection circuit VD detects the above-mentioned welding voltage Vw and outputs voltage detection signal Vd. The voltage filter circuit VAV receives this voltage detection signal Vd as input, removes high frequency components using a low-pass filter, and outputs a voltage filter signal Vav. The cutoff frequency of the low-pass filter is set to about 0.1 to 1 kHz. Since the value of this voltage filter signal Vav and the arc length are in a substantially proportional relationship, the arc length is detected by this voltage filter signal Vav. This circuit removes high-frequency noise from the inverter circuit to prevent false arc length detection. Further, this circuit is provided in order to more accurately detect changes in arc length by removing temporary fluctuations caused by gas ejection from the molten pool.

The current detection circuit ID detects the above-mentioned welding current Iw and outputs a current detection signal Id. The energization determination circuit CD receives this current detection signal Id as an input, and outputs an energization determination signal Cd that becomes High level when this value is equal to or greater than a threshold value. This energization determination signal Cd is a signal that becomes High level when the welding current Iw is energized. Therefore, the threshold value is set to about 5A.

The robot control device RC stores a work program taught in advance, controls the operation of a robot (not shown) according to this work program, and outputs a welding start signal St to the welding power source.

The first voltage setting circuit V1R outputs a predetermined first voltage setting signal V1r. The second voltage setting circuit V2R outputs a predetermined second voltage setting signal V2r. The steady voltage setting circuit VCR outputs a predetermined steady voltage setting signal Vcr. Here, V1r<V2r<Vcr is set.

The first feed rate setting circuit F1R outputs a predetermined first feed rate setting signal F1r. The second feed speed setting circuit F2R outputs a predetermined second feed speed setting signal F2r. The steady feed rate setting circuit FCR outputs a predetermined steady feed rate setting signal Fcr. Here, F1r<F2r<Fcr is set.

The hot start period setting circuit THR outputs a predetermined hot start period setting signal Thr.

The first period end determination circuit ST1 inputs the voltage filter signal Vav described above, the first voltage setting signal V1r described above, and a period signal Ms to be described later, and when the period signal Ms=3 (first period T1), determines whether Vav ≧V1r, and when a predetermined first period has elapsed, the first period end signal St1 which becomes High level for a short time is output. The first predetermined period may be set to 0 seconds. Furthermore, when the elapsed time of the first period T1 exceeds a predetermined first upper limit time, the first period end signal St1 may be output at that point.

The second period end determination circuit ST2 inputs the voltage filter signal Vav described above, the second voltage setting signal V2r described above, and a period signal Ms described later, and when the period signal Ms=4 (second period T2), the circuit ST2 detects Vav ≧V2r, and when a predetermined second period elapses thereafter, a second period end signal St2 that becomes High level for a short time is output. The second predetermined period may be set to 0 seconds. Further, when the elapsed time of the second period T2 exceeds a predetermined second upper limit time, the second period end signal St2 may be output at that point.

The period setting circuit MS inputs the above-mentioned welding start signal St, the above-mentioned energization determination signal Cd, the above-mentioned hot start period setting signal Thr, the above-mentioned first period end signal St1, and the above-mentioned second period end signal St2, The following processing is performed and a period signal Ms is output.
1) When the welding start signal St changes to High level (start), a period setting signal Ms whose value changes from 0 to 1 is output. The period when Ms=1 is a slowdown feeding period.
2) After that, when the energization determination signal Cd changes to High level (energization), a period setting signal Ms whose value becomes 2 is output. The period when Ms=2 is the hot start period Th.
3) After that, when the period determined by the hot start period setting signal Thr has elapsed, the period setting signal Ms whose value becomes 3 is output. The period when Ms=3 is the first period T1.
4) After that, when the first period end signal St1 becomes High level for a short time, the period setting signal Ms whose value becomes 4 is output. The period when Ms=4 is the second period T2.
5) After that, when the second period end signal St2 becomes High level for a short time, the period setting signal Ms whose value becomes 5 is output. The period of Ms=5 is a steady period.

The voltage setting circuit VR inputs the first voltage setting signal V1r, the second voltage setting signal V2r, the steady voltage setting signal Vcr, and the period signal Ms, and sets the first voltage when Ms≦3. The voltage setting signal Vr is outputted as the value of the setting signal V1r, when Ms=4, the value of the second voltage setting signal V2r, and when Ms=5, the value of the steady voltage setting signal Vcr.

The voltage error amplification circuit EV amplifies the error between the voltage setting signal Vr and the voltage filter signal Vav, and outputs a voltage error amplification signal Ev.

The hot start current setting circuit IHR outputs a predetermined hot start current setting signal Ihr. The current error amplification circuit EI amplifies the error between this hot start current setting signal Ihr and the above-mentioned current detection signal Id, and outputs a current error amplification signal Ei.

The control method switching signal generation circuit CS inputs the above-mentioned period signal Ms, and when Ms=3 to 5, the control mode is set to High level (constant voltage control), and during other periods, the control mode is set to Low level (constant current control). A system switching signal Cs is output. The control switching circuit SW receives the voltage error amplification signal Ev, the current error amplification signal Ei, and the control method switching signal Cs as input, and when Cs=Low level (constant current control), outputs the current error amplification signal Ei. is outputted as the error amplified signal Ea, and when Cs=High level (constant voltage control), the voltage error amplified signal Ev is outputted as the error amplified signal Ea. The drive circuit DV inputs this error amplification signal Ea and the above-mentioned welding start signal St, performs PWM modulation control based on the error amplification signal Ea when the welding start signal St is at a high level, and performs PWM modulation control based on the above-mentioned power supply main circuit PM. It outputs a drive signal Dv for driving the inverter circuit inside, and stops outputting the drive signal Dv when the welding start signal St is at Low level.

The feed rate setting circuit FR receives as input the first feed rate setting signal F1r, the second feed rate setting signal F2r, the steady feed rate setting signal Fcr, and the period signal Ms. When = 0 and 1, it becomes the predetermined slowdown feeding speed, when Ms = 2 and 3, it becomes the value of the first feeding speed setting signal F1r, and when Ms = 4, it becomes the value of the second feeding speed setting signal. When Ms=5, the feeding rate setting signal Fr is outputted having the value of the steady feeding rate setting signal Fcr.

The feed control circuit FC inputs the above-mentioned feed speed setting signal Fr and the above-mentioned welding start signal St, and when the welding start signal St is at a high level, feeds the welding wire 1 at a speed determined by the feed speed setting signal Fr. A feed control signal Fc for feeding is output to the feed motor WM, and when the welding start signal St is at a low level, a feed control signal Fc for stopping the feed is output to the feed motor WM. Output to.

FIG. 2 is a timing chart of each signal in the arc welding power source of FIG. 1. The same figure (A) shows the time change of the welding start signal St, the same figure (B) shows the time change of the control method switching signal Cs, and the same figure (C) shows the time change of the welding wire feeding speed Fw. , the same figure (D) shows the time change of the feed speed setting signal Fr, the same figure (E) shows the time change of the voltage setting signal Vr, and the same figure (F) shows the time change of the welding current Iw. , the same figure (G) shows the time change of the welding voltage Vw, the same figure (H) shows the time change of the first period end signal St1, and the same figure (I) shows the time change of the second period end signal St2. show. The figure illustrates the case of welding using a robot. This will be explained below with reference to the same figure.

In the figure, the period from time t1 to t2 becomes the slowdown feeding period of the period signal Ms=1 in FIG. 1, the period from time t2 to t3 becomes the hot start period Th of the period signal Ms=2 in FIG. The period from t3 to t4 becomes the first period T1 of the period signal Ms=3 in FIG. 1, the period from time t4 to t5 becomes the second period T2 of the period signal Ms=4 in FIG. The period signal Ms=1 corresponds to a steady period of 5. The feeding speed setting signal Fr shown in FIG. During the first period T1, the value is the value of the first feed speed setting signal F1r in FIG. 1. During the second period T2, it is the value of the second feed speed setting signal F2r in FIG. This becomes the value of the feeding speed setting signal Fcr. Here, slowdown feeding speed<first feeding speed setting signal F1r<second feeding speed setting signal F2r<steady feeding speed setting signal Fcr. The voltage setting signal Vr shown in FIG. 1, and becomes the value of the steady voltage setting signal Vcr during the steady period. Here, first voltage setting signal V1r<second voltage setting signal V2r<steady voltage setting signal Vcr. The voltage filter signal Vav in FIG. 1 is a signal obtained by removing high frequency noise from the welding voltage Vw, and will be explained below as Vw=Vav.

At time t1, when the robot moves and the welding torch reaches the welding start position, a welding start signal St is output from the robot control device to the welding power source.

(1) Slow-down feeding period from time t1 to t2 As shown in FIG. 2(A), at time t1, when the welding start signal St from the robot control device becomes High level, the output of the welding power source is started. Therefore, as shown in the same figure (G), a no-load voltage is applied between the welding wire and the base metal. At the same time, as shown in FIG. 3C, the feeding speed Fw becomes a slow slowing feeding speed of about 1 to 2 m/min, and the welding wire gradually approaches the base metal. As shown in FIG. 3B, the control method switching signal Cs is at a low level (constant current control) until time t3 when the hot start period Th ends, and thereafter is at a high level (constant voltage control). This control method switching signal Cs is a signal for switching the output control method of the welding power source between constant current control and constant voltage control.

(2) Hot start period Th from time t2 to t3
At time t2, when the welding wire and the base metal come into contact and become electrically conductive, the welding voltage Vw suddenly decreases to a short-circuit voltage value of about several volts, as shown in FIG. At the same time, as shown in FIG. 5F, the supply of welding current Iw is started, and a predetermined hot start current Ih is supplied during a predetermined hot start period Th from time t2 to t3. During this hot start period Th, as shown in FIG. 4B, the control method switching signal Cs is at a low level, so constant current control is performed. The hot start period Th is set to about 5 ms, for example, and the hot start current Ih is set to about 500 A, for example. Both values are set to appropriate values depending on the material, diameter, etc. of the welding wire. This hot start current Ih is applied in order to quickly melt the tip of the welding wire and generate an arc. Therefore, an arc occurs at time t21 after a short period of about 1 ms has elapsed from time t2. When an arc occurs, the welding voltage Vw rapidly increases to an arc voltage value of several tens of volts, as shown in FIG. During the period from time t21 to time t3, the tip of the welding wire is melted by the hot start current Ih, so the arc length gradually increases. In response to this, the welding voltage Vw gradually increases in value during the period from time t21 to time t3, as shown in FIG. Further, as shown in FIG. 1(D), the feeding speed setting signal Fr becomes the value of the first feeding speed setting signal F1r in FIG. 1 at time t2, and as shown in FIG. The feeding speed Fw increases with a slope during the period from time t2 to time t3. This hot start period Th is not an essential period that must absolutely be provided. Even during the first period T1, which will be explained in the next section, from when the welding wire comes into contact with the base metal, a large welding current Iw is applied during the short circuit period, so depending on the welding conditions, arc generation may not be such a problem. Does not occur.

(3) First period T1 from time t3 to t4
When the hot start period Th ends at time t3, the control method switching signal Cs changes to High level, as shown in FIG. 3B, so that the control is switched to constant voltage control. As shown in FIG. 5E, the value of the voltage setting signal Vr at time t3 is the value of the first voltage setting signal V1r in FIG. 1, so constant voltage control is performed using this setting value. As shown in FIG. 3G, the value of the welding voltage Vw is smaller than the value corresponding to the first voltage setting signal V1r at time t3, so the value gradually increases due to the constant voltage control. Along with this, the arc length also gradually increases. Then, at time t31, the value of the welding voltage Vw becomes equal to the value corresponding to the first voltage setting signal V1r, as shown in FIG. Then, at time t4 when a predetermined first period has elapsed from time t31, the first period end signal St1 becomes High level for a short period of time, as shown in (H) in the figure. In response to this, the first period T1 ends and the second period T2 begins. As shown in FIG. 3G, the welding voltage Vw gradually increases from time t21, reaches the value of the first voltage setting signal V1r at time t31, and maintains that value until time t4. The arc length gradually increases from time t21, reaches the first arc length at time t31, and maintains that value until time t4.

As shown in FIG. 1D, the value of the feed rate setting signal Fr at time t3 is the value of the first feed rate setting signal F1r in FIG. As shown in FIG. 3C, the feeding speed Fw is a smaller value than the value corresponding to the first feeding speed setting signal F1r at time t3, so the value gradually becomes faster. Then, at a time point earlier than time t31, as shown in FIG. 4(C), the feed rate Fw becomes equal to the value corresponding to the first feed rate setting signal F1r. The reason why the time when the feed rate Fw=F1r is earlier than the time t31 when the welding voltage Vw=V1r is because the transient speed of the feed rate Fw is faster than the transient speed of the welding voltage Vw. As shown in FIG. 5C, the feeding speed Fw gradually accelerates from time t2, reaches the value of the first feeding speed setting signal F1r at a point earlier than time t31, and maintains that value until time t4. maintain. As shown in (F) in the figure, the welding current Iw rapidly decreases from the hot start current value Ih at time t3, and then gradually increases until the feeding speed reaches Fw = F1r. 1 welding current value, and maintains that value until time t4.

In the above, the timing at which the first period T1 ends at time t4 is when Vw≧V1r becomes satisfied at time t31, and the first predetermined period has elapsed thereafter. Here, the first predetermined period is set to about 20 ms, for example. The transition period from time t3 to t31 is about 50 ms, and the first period T1 from time t3 to t4 is about 70 ms. The transition period from time t3 to Fw=F1r is about 30 ms. Here, the first predetermined period may be set to 0 seconds and this period may be deleted. Furthermore, when the elapsed time of the first period T1 becomes equal to or longer than the first upper limit time, the first period T1 may be forced to end. The first upper limit time is set to about 100 ms, for example.

(4) Second period T2 from time t4 to t5
As shown in FIG. 5E, the value of the voltage setting signal Vr at time t4 is the value of the second voltage setting signal V2r in FIG. 1, so constant voltage control is performed using this setting value. As shown in FIG. 3G, the value of the welding voltage Vw is smaller than the value corresponding to the second voltage setting signal V2r at time t4, so the value gradually increases due to the constant voltage control. Along with this, the arc length also gradually increases. Then, at time t41, the value of the welding voltage Vw becomes equal to the value corresponding to the second voltage setting signal V2r, as shown in FIG. Then, at time t5 when a predetermined second period has elapsed from time t41, the second period end signal St2 becomes High level for a short time, as shown in FIG. In response to this, the second period T2 ends and transitions to a steady period. As shown in FIG. 3G, the welding voltage Vw gradually increases from time t4, reaches the value of the second voltage setting signal V2r at time t41, and maintains that value until time t5. The arc length gradually increases from time t4, reaches the second arc length at time t41, and maintains that value until time t5.

As shown in FIG. 1D, the value of the feed rate setting signal Fr at time t4 is the value of the second feed rate setting signal F2r in FIG. As shown in FIG. 4C, the feeding speed Fw is a smaller value than the value corresponding to the second feeding speed setting signal F2r at time t4, so the value gradually becomes faster. Then, at a time earlier than time t41, as shown in FIG. 4C, the feed rate Fw becomes equal to the value corresponding to the second feed rate setting signal F2r. The reason why the time when the feed rate Fw=F2r is earlier than the time t41 when the welding voltage Vw=V2r is because the transient speed of the feed rate Fw is faster than the transient speed of the welding voltage Vw. As shown in FIG. 5C, the feeding speed Fw gradually accelerates from time t2, reaches the value of the second feeding speed setting signal F2r at a point earlier than time t41, and maintains that value until time t5. maintain. As shown in (F) in the figure, the welding current Iw gradually increases from the first welding current value at time t4, reaches the second welding current value when the feeding speed Fw = F2r, and reaches the second welding current value at time t4. The value is maintained until t5.

In the above, the timing at which the second period T2 ends at time t5 is when Vw≧V2r becomes satisfied at time t41, and the second predetermined period has elapsed thereafter. Here, the second predetermined period is set to about 20 ms, for example. The transition period from time t4 to t41 is about 50 ms, and the second period T2 from time t4 to t5 is about 70 ms. The transition period from time t3 to Fw=F1r is about 30 ms. Here, the second predetermined period may be set to 0 seconds and this period may be deleted. Furthermore, when the elapsed time of the second period T2 becomes equal to or longer than the second upper limit time, the second period T2 may be forced to end. The second upper limit time is set to about 100 ms, for example.

(5) Steady-state period after time t5 As shown in FIG. Voltage control is performed. As shown in FIG. 5G, the value of the welding voltage Vw is smaller than the value corresponding to the steady voltage setting signal Vcr at time t5, so the value gradually increases due to the constant voltage control. Along with this, the arc length also gradually increases. Then, at time t51, the value of the welding voltage Vw converges to the value corresponding to the steady voltage setting signal Vcr, as shown in FIG. Then, the arc length gradually increases from time t5 and converges to a steady arc length at time t51. The transition period from time t5 to t51 is about 30 ms.

As shown in FIG. 1D, the value of the feed rate setting signal Fr at time t5 is the value of the steady feed rate setting signal Fcr in FIG. As shown in FIG. 4C, the feeding speed Fw is a smaller value than the value corresponding to the steady feeding speed setting signal Fcr at time t5, so the value gradually becomes faster. Then, at a time point earlier than time t51, as shown in FIG. 4C, the feed rate Fw converges to a value corresponding to the steady feed rate setting signal Fcr. The reason why the time point when the feed rate Fw=Fcr is earlier than the time t51 when the welding voltage Vw=Vcr is because the transient speed of the feed speed Fw is faster than the transient speed of the welding voltage Vw. As shown in FIG. 4C, the feed rate Fw gradually accelerates from time t5 and converges to the value of the steady feed rate setting signal Fcr at a time earlier than time t51. As shown in FIG. 5F, the welding current Iw gradually increases from the second welding current value at time t5, and converges to the steady welding current value when the feeding speed Fw=Fcr. The transition period from time t5 to the time when Fw=Fcr is approximately 20 ms.

The effects of this embodiment will be explained below. According to the arc welding power source according to the present embodiment, the period setting section outputs a period signal that transitions over time to a first period, a second period, and a steady period when the welding current starts flowing; When is the first period, it becomes the first voltage setting value, when the period signal is the second period, it becomes the second voltage setting value, when the period signal is a steady period, it becomes the steady voltage setting value, and the first voltage A voltage setting section outputs a voltage setting signal in which the setting value<second voltage setting value<steady voltage setting value, and when the period signal is in the first period, the feeding speed setting value is set, and when the period signal is in the second period, When the period signal is a steady period, it becomes the second feeding speed setting value, and when the period signal is a steady period, it becomes the steady feeding speed setting value, and the first feeding speed setting value < the second feeding speed setting value < the steady feeding speed setting value. a feed speed setting section that outputs a feed speed setting signal that is a value, and a period setting section that controls the welding voltage value to increase during the first period and become equal to the first voltage setting value, the welding voltage value increases to become equal to the first voltage setting value, the welding voltage value increases and becomes equal to the first voltage setting value during the first period. When the welding voltage value increases during the second period and becomes equal to the second voltage setting value, the period transitions to a steady period. In this embodiment, a first period, a second period, and a steady period are provided at the start of welding, and control is performed such that the welding voltage value converges to a set value and then shifts to the next period. Accordingly, the arc length once converges in each engine and then shifts to the next period. For this reason, it is possible to suppress overshoot and undershoot before the arc length converges to the steady arc length. For this reason, in this embodiment, it is possible to always obtain good welding quality at the welding start portion without being affected by various welding conditions.

Furthermore, according to the arc welding power source according to the present embodiment, the period setting section sets the welding voltage value to the welding voltage value when the welding voltage value increases during the first period and becomes equal to the first voltage setting value and then the first predetermined period elapses. It is preferable that the welding voltage value increases during the second period and becomes equal to the second voltage setting value, and then transitions to the steady period after a second predetermined period has elapsed. By providing the first predetermined period and the second predetermined period, it is possible to bring the arc length into a sufficient convergence state in each engine. As a result, overshoot and undershoot of the arc length can be more reliably suppressed to a smaller value, so that welding quality at the welding start portion can be further improved.

Furthermore, according to the arc welding power source according to the present embodiment, the period setting section transitions to the second period when the elapsed time of the first period becomes equal to or more than the first upper limit time, and when the elapsed time of the second period It is preferable to shift to a steady period when the time exceeds 2 upper limit times. When the elapsed time of the first period and the elapsed time of the second period exceed a predetermined time, the welding quality at the welding start portion may deteriorate. In this embodiment, such a case can be suppressed.

The arc welding power source according to this embodiment can be used for consumable electrode type arc welding. Examples of consumable electrode arc welding include carbon dioxide arc welding, MAG welding, MIG welding, and pulsed arc welding.

1 Welding wire 2 Base material 3 Arc 4 Welding torch 5 Feed roll CD Energization discrimination circuit Cd Energization discrimination signal CS Control method switching signal generation circuit Cs Control method switching signal 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 F1R First feed speed setting circuit F1r First feed speed setting signal F2R Second feed speed setting circuit F2r Second feed speed setting signal FC Feed Control circuit Fc Feed control signal FCR Steady feed rate setting circuit Fcr Steady feed rate setting signal FR Feed rate setting circuit Fr Feed rate setting signal Fw Feed rate ID Current detection circuit Id Current detection signal Ih Hot start current IHR Hot start current setting circuit Ihr Hot start current setting signal Iw Welding current MS Period setting circuit Ms Period signal PM Main power supply circuit RC Robot controller St Welding start signal ST1 1st period end determination circuit St1 1st period end signal ST2 2nd period End determination circuit St2 Second period end signal SW Control switching circuit T1 First period T2 Second period Th Hot start period THR Hot start period setting circuit Thr Hot start period setting signal V1R First voltage setting circuit V1r First voltage setting signal V2R Second voltage setting circuit V2r Second voltage setting signal VAV Voltage filter circuit Vav Voltage filter signal VCR Steady voltage setting circuit Vcr Steady voltage setting signal VD Voltage detection circuit Vd Voltage detection signal VR Voltage setting circuit Vr Voltage setting signal Vw Welding voltage WM Transmission feed motor

Claims (3)

an output control unit that controls the welding voltage value to the value of the voltage setting signal;
a feed control unit that controls the feed speed of the welding wire to the value of the feed speed setting signal;
In an arc welding power source equipped with
a period setting unit that outputs a period signal that transitions over time to a first period, a second period, and a steady period when the welding current starts flowing;
When the period signal is in the first period, it is a first voltage setting value, when the period signal is in the second period, it is a second voltage setting value, and when the period signal is in the steady period, it is a steady voltage setting value. a voltage setting unit that outputs the voltage setting signal, which is a voltage setting value and satisfies the first voltage setting value<the second voltage setting value<the steady voltage setting value;
When the period signal is in the first period, it becomes the first feeding speed setting value; when the period signal is in the second period, it becomes the second feeding speed setting value; and when the period signal is in the steady period, it becomes the second feeding speed setting value. In some cases, the feed speed setting value becomes the steady feed speed setting value, and the feed speed outputs the feed speed setting signal such that the first feed speed setting value<the second feed speed setting value<the steady feed speed setting value. comprising a setting section;
The period setting unit is configured to shift to the second period when the welding voltage value increases during the first period and becomes equal to the first voltage setting value, and to increase the welding voltage value during the second period. When the voltage becomes equal to the second voltage setting value, the steady-state period begins;
An arc welding power source characterized by: The period setting unit is configured to shift to the second period when a first predetermined period elapses after the welding voltage value increases during the first period and becomes equal to the first voltage setting value, and to set the welding voltage value to the second period. When a second predetermined period elapses after the welding voltage value increases during the welding voltage value and becomes equal to the second voltage setting value, the welding voltage value shifts to the steady period.
The arc welding power source according to claim 1, characterized in that: The period setting unit transitions to the second period when the elapsed time of the first period becomes a first upper limit time or more, and transitions to the steady period when the elapsed time of the second period becomes more than a second upper limit time. ,
The arc welding power source according to claim 1 or 2, characterized in that:

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