JP2001340964A - Controlling method for multi electrode pulse arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a method for multi electrode pulse arc welding in which welding is performed by generating two arcs between a welded article and two welding wires which is fed from one welding torch and insulated electrically from each other, and in which mutual arc interference caused by forces that two arcs interact with each other makes generating condition of the arcs unstable. SOLUTION: This invention means that in the first time, base current BIb2 which is larger than a normal value, is impressed to the second arc during the time from the starting point of the first arc peak current exciting time Atp to the intermediate point of delay time Tod, peak current BIp is impressed during the time from the intermediate point to the ending point of the first arc peak current exciting time Atp, then in the second time, base current BIb2 which is larger than the normal value during the first arc peak current exciting time ATp, furthermore the third time current-carrying same as the second time is carried out, and one group composed of the first, the second and the third current-carrying, is repeatedly electrified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to multi-electrode pulse arc welding in which two arcs are generated between one welding torch and two welding wires electrically insulated from each other and an object to be welded. The present invention relates to a multi-electrode pulsed arc welding control method capable of suppressing an unstable arc generation state due to mutual interference of arcs caused by a force acting between two arcs.

[0002]

2. Description of the Related Art In a multi-electrode pulse arc welding method, two welding wires are fed through two electrically insulated contact tips provided on one welding torch, and the welding wire and the work to be welded are connected to each other. The welding is performed by generating two pulse arcs between the two. In this welding method, a high welding amount can be obtained because two welding wires are melted at the same time, so that high-speed welding of more than 4 [m / min] can be performed in the welding of a thin plate. In multi-layer welding, welding can be performed with a reduced number of layers, and the efficiency of welding work can be increased. Further, since the present welding method is a pulse arc welding method, spatter is less generated and a beautiful bead appearance can be obtained. The present welding method can be used for various metals such as steel, stainless steel, and aluminum alloy. However, the conventional multi-electrode pulse arc welding method has a problem that the arc generation state becomes unstable due to the mutual interference of the arcs due to the force acting between the two arcs, as described later. To solve this problem, a patent application was filed on March 6, 2000 by the same applicant as the present applicant (Japanese Patent Application No.
00-65691). The present invention is an invention that solves the problem in the invention described in the specification and drawings of the earlier application (hereinafter, referred to as the earlier application invention). Hereinafter, the multi-electrode pulse arc welding control method of the present invention and problems to be solved will be described.

FIG. 1 is a block diagram of a multi-electrode pulse arc welding apparatus according to the prior application. As shown in the figure, this welding device is composed of a first welding power supply APS, a first wire feeding device AWF, a second welding power feeding device BPS, a second wire feeding device BWF, and a welding torch 4. It is configured. Hereinafter, these components will be described with reference to FIG.

A first contact tip A41 and a second contact tip B41, which are electrically insulated from each other, are mounted on the welding torch 4, and the first welding wire A1 is passed through these contact tips A41 and B41.
And the second welding wire B1 is fed and fed, and the first arc A3 and the second arc B3
Occurs. One weld pool 21 is formed in the workpiece 2 by these two arcs A3 and B3.

[0005] The first welding power supply APS is a welding power supply for pulse arc welding, outputs a feed control signal Wc to a first wire feeder AWF, and outputs a first welding wire A1 to a first welding wire A1. The first welding voltage AVw is supplied to
Is supplied with the first welding current AIw. First
The wire feeder AWF controls the feed of the first welding wire A1 according to the feed control signal Wc described above. On the other hand,
Second welding power supply device BPS and second wire feeding device B
The same applies to WF.

FIG. 2 is a schematic diagram of an arc generator for explaining the mutual interference of the arcs acting on the two arcs A3 and B3. The figure shows a case where AIp> BIb, where a first peak current AIp is applied to the first welding wire A1, and a second base current BIb is applied to the second welding wire B1. Hereinafter, description will be made with reference to FIG.

As shown in FIG. 1, the first arc A3 has a contraction force AFX caused by an arc generated by the application of the first peak current AIp for energizing the inside of the first arc A3.
And a force AFZ due to a magnetic field generated by the application of the second base current BIb for energizing the other arc. The contraction force AFX due to the arc acts as a force for maintaining the arc shape as it is, and the force AFZ due to the magnetic field acts as a force for pulling in the direction of the other arc. That is, the contraction force A due to the above arc
FX acts as a force for suppressing the deformation of the arc shape, while the force AFZ due to the magnetic field acts as a force for deforming the arc shape. As described above, since AIp> BIb, AFX> AFZ, and as a result, the force for maintaining the arc shape is larger, so that the first arc A3 is stable.

On the other hand, the second arc B3 has a contraction force BFX due to the arc and a force BFZ due to the magnetic field as described above.
Works. Here, as described above, AIp> BIb
BFZ> BFX, so that the second arc B3 is drawn in the direction of the first arc A3,
The arc shape is greatly deformed, and the arc generation state becomes unstable.

As described above, when there is a large difference between the current values for energizing the two arcs, the arc with the small current value is attracted to the arc with the large current value and deforms (mutual interference of the arcs) to generate an arc. The state becomes unstable.
On the other hand, when the current values for energizing the two arcs are approximately the same, the influence of the mutual interference of the arcs on the arc generation state is small, and both arcs are stable.

FIG. 3 is a current / voltage waveform diagram of the multi-electrode pulsed arc welding control method of the prior invention which can suppress the instability of the arc generation state due to the mutual interference of the arcs. FIG. 3A shows the time change of the first welding current AIw, FIG. 3B shows the time change of the first welding voltage AVw, and FIG. 3C shows the second welding current AIw. Current B
Iw shows a change over time, and FIG. 3D shows a change over time of the second welding voltage BVw. Hereinafter, description will be made with reference to FIG.

As shown in FIG. 1, in the invention of the prior application, the energization of the first welding current AIw and the energization of the second welding current BIw are synchronized, and the second welding current BIw is synchronized with the second welding current BIw. Cycle of welding current BIw (second pulse cycle BTf)
Is n times the length of the cycle (first pulse cycle ATf) of the first welding current AIw. FIG.
Is 3 as an example.

Energization of the first welding current AIw During the period from time t1 to time t2 (the first peak current energization time AT
p) is the first peak current A, as shown in FIG.
Ip is energized, and a first peak voltage AVp corresponding to the energization is applied as shown in FIG. Subsequently, during the period from time t2 to t3, as shown in FIG.
, And a first base voltage AVb corresponding to the conduction is applied as shown in FIG. The period from time t1 to time t3 is the first pulse period ATf.

Energization of the second welding current BIw The energization period (second peak current energization time BTp) of the first peak current AIp for the first time from time t1 to t2 is as shown in FIG. , The second peak current BIp1 is supplied, and the second base current BIb1 having a normal value is supplied during the supply period of the first base current AIb from time t2 to t3. Subsequently, the first peak current A for the second time from time t3 to t4
During the current supply period of Ip, the second base current BIb2 having a value larger than the normal value is supplied. During the current supply period of the first base current AIb from time t4 to time t5, the second base current BIb1 having the above-described normal value is supplied. Is turned on. Further, during the period from time t5 to t6, power is supplied similarly to the second time from time t3 to t5,
The first to third energizations at times t1 to t6 are repeatedly applied as a set. Further, as shown in FIG. 4D, during the period from time t1 to t2, the second peak voltage BVp corresponding to the above-described energization is applied, and from time t2 to t6
Is the second base voltage BV corresponding to the above-described energization.
b is applied. The length of the second pulse period BTf is the first
Is three times the length of the pulse period ATf, and is equal to the magnification n = 3.

FIG. 1 illustrates a case where the magnification is n = 3.
The above-mentioned time t3 to time t3 according to the magnification n which is the above integer.
The energization similar to the second energization of No. 5 is repeated up to the nth energization, and the energization of the first to nth energizations described above is repeated as one set, and energization is repeated. Also, when the magnification n = 1, the times t1 to t
The energization is repeated by setting the energization of No. 3 as one set.

Next, the state of occurrence of two arcs in each period described above will be described. Period of Time t1 to t2 During this period, the first arc has the first peak current AI
p conducts, and the second arc has a second peak current BIp
Are conducted, and the current value for energizing both arcs is approximately the same as AIp 同 BIp. Therefore, as described above, the mutual interference between the arcs does not make the generation state of both arcs unstable.

During a period from time t2 to t3, during this period, the first arc is supplied to the first base current AI
b, the second base current BIb1 having a normal value is applied to the second arc, and AIb ≒ BIb1 is equal to the current value for energizing both arcs. Therefore, as described above, The occurrence state of both arcs does not become unstable due to mutual interference of the arcs.

During the period from time t3 to t4, during this period, the first peak current AI is applied to the first arc.
p is energized, and the second arc is energized by the second base current BIb2 having a value larger than the normal value. Here, temporarily
Assuming that a second base current BIb1 having a normal value is supplied to the second arc, as described above with reference to FIG.
> BIb1 and the force BFZ by the magnetic field> the contraction force BFX by the arc, the second arc is deformed, and the arc generation state becomes unstable. Therefore, in the prior invention, the BF
By applying the second base current BIb2 having a value larger than the normal value so as to satisfy Z <BFX, the deformation of the second arc is suppressed, and the unstable arc generation state is suppressed.

The period from time t4 to t5 The description during this period is the same as that described above, and the arc generation state is stable. The period from time t5 to t6 The description during this period is the same as the above-mentioned item and item.
The arc generation state is stable.

As described above, in the invention of the prior application, instability of the arc generation state due to the mutual interference of the arcs does not occur over the entire period of FIG.

FIG. 4 is a block diagram showing a circuit configuration of the first welding power supply APS and the second welding power supply BPS in the above-mentioned prior invention. Hereinafter, each circuit block will be described with reference to FIG.

The first welding power supply APS is composed of circuit blocks within a range surrounded by a dashed line, and these circuit blocks will be described below. The output control circuit INV controls the output using a commercial power supply as an input and supplies an output suitable for an arc load. Generally, as the output control circuit INV, an inverter control circuit, a chopper control circuit, a thyristor phase control circuit and the like are commonly used.
For example, the above inverter control circuit is formed from the following circuits. That is, a primary rectifier circuit for rectifying a commercial power supply, a smoothing circuit for smoothing a rectified rippled voltage, an inverter circuit for converting a smoothed DC voltage to a high-frequency AC, and a high-frequency AC suitable for an arc load. A high-frequency transformer that reduces the voltage to a reduced voltage, a secondary-side rectifier circuit that rectifies the stepped-down AC again, and a DC reactor that smoothes the rectified rippled DC. According to Ei, a plurality of sets of power transistors forming the inverter circuit are controlled to perform output control.

The voltage detection circuit VD detects the first welding voltage AV
Detects w and outputs an averaged voltage detection signal Vd.
The voltage setting circuit VS is provided outside the power supply device and outputs a voltage setting signal Vs. The voltage error amplification amplifier EV amplifies an error between the voltage detection signal Vd as a feedback signal and the voltage setting signal Vs as a target value, and outputs a voltage error amplification signal Ev. V /
The F conversion circuit VF performs V / F conversion using the above-described voltage error amplification signal Ev as an input, and outputs a V / F conversion signal Vf. The peak current conduction time setting circuit TP outputs a peak current conduction time setting signal Tp. The mono-multi vibrator MM is triggered by the change of the V / F conversion signal Vf from a low level to a high level as a trigger, and becomes the high level for the time set by the peak current conduction time setting signal Tp as described above with reference to FIG. The first pulse period signal ATf is output.

The modulation circuit MC surrounded by a dotted line is formed by the voltage error amplifier circuit EV, V / F conversion circuit VF, peak current conduction time setting circuit TP, and monomultivibrator MM. The modulation circuit MC receives the voltage detection signal Vd and the voltage setting signal Vs, and outputs the first pulse period signal ATf by frequency modulation control based on an error between the signals. As this modulation method, pulse width modulation control is used as a conventional technique in addition to the frequency modulation control described above.

The first peak current setting circuit AIP outputs a preset first peak current setting signal AIp.
The first base current setting circuit AIB includes a first base current setting circuit AIB.
Of the base current setting signal AIb. The first switching circuit ASW sets the first pulse period signal ATf to Hi.
When the signal is at the gh level, it is connected to the a side so that the first peak current setting signal AIp is supplied to the first current control setting signal AIsc.
And the above-mentioned first pulse period signal ATf becomes L
When the signal is at the low level, the first base current setting signal AIb is connected to the b side and is connected to the first current control setting signal AIsc.
Output as The current detection circuit ID detects the first welding current AIw and outputs a current detection signal Id. The current error amplification circuit EI amplifies an error between the current detection signal Id, which is a feedback signal, and the first current control setting signal AIsc, which is a target value, and outputs a current error amplification signal Ei. Output control is performed by the output control circuit INV according to the current error amplification signal Ei,
A first welding voltage AVw is applied.

The first feed speed setting circuit AWS is provided outside the power supply unit and has a first feed speed setting signal A.
Output Ws. The first feed control circuit AWC receives the above-mentioned first feed speed setting signal AWs and outputs a first feed control signal AWc. First wire feeding device A
WF is the first feed control signal AWc according to the first feed control signal AWc.
Of the welding wire A1 is controlled.

Next, each circuit block constituting the second welding power supply unit BPS will be described. Magnification setting circuit NS
Outputs a magnification setting signal n which is an integer of 2 or more. The period conversion circuit TC receives the first pulse period signal ATf and the magnification setting signal n output from the first welding power supply device APS as inputs, and as described above with reference to FIG. The signal is synchronized with the signal ATf and converted into a signal having a period n times as long as the signal, and a second pulse period signal BTf is output.

The second base current setting circuit BIB receives the first pulse period signal ATf as an input and when the input is at a low level (the first base current setting signal AIb).
b), the second base current setting signal BIb1 having a normal value set in advance, and when the input signal thereof is at the High level (when switching to the first peak current setting signal AIp),
A second base current setting signal BIb2 having a value greater than a preset normal value is output as a second base current setting signal BIb.

The second switching circuit BSW is connected to the a side when the second pulse period signal BTf is at the High level, and uses the second peak current setting signal BIp as the second current control setting signal BIsc. When the signal is at the low level, it is connected to the b side and outputs the second base current setting signal BIb as the second current control setting signal BIsc. The current detection circuit ID is the second welding current BIw
And outputs a current detection signal Id. The current error amplifier EI amplifies an error between the current detection signal Id as a feedback signal and the second current control setting signal BIsc as a target value, and amplifies the current error amplified signal Ei.
Is output. Output control is performed according to the current error amplification signal Ei, and the second welding voltage BVw is applied.

The second feed speed setting circuit BWS is provided outside the power supply device and has a second feed speed setting signal B
Output Ws. The second feed control circuit BWC receives the above-mentioned second feed speed setting signal BWs and outputs a second feed control signal BWc. Second wire feeding device B
WF is determined by the second feed control signal BWc.
Of the welding wire B1 is controlled.

FIG. 5 is a timing chart of each signal in the above-described welding apparatus of the prior application. FIG. 3A shows the time change of the first welding current AIw, FIG. 3B shows the time change of the first welding voltage AVw, and FIG. 3C shows the V / F conversion. FIG. 7D shows the time change of the signal Vf, FIG. 7D shows the time change of the first pulse cycle signal ATf, and FIG. 7E shows the time change of the second pulse cycle signal BTf. FIG. 7F shows a time change of the second base current setting signal BIb. Hereinafter, description will be made with reference to FIG.

The above-described V / F conversion circuit VF has a first pulse period ATf which is controlled so that the average value of the first welding voltage AVw and the voltage setting signal Vs shown in FIG. V / shown in FIG.
An F-converted signal Vf is output. This V / F conversion signal Vf
Are the basic signals that determine the operation timing of the other signals. The V / F conversion signal Vf goes to the High level for a short time at times t1, t3, and the like in each of the first pulse periods ATf.

As shown in FIG. 2D, the first pulse period signal ATf is such that the V / F conversion signal Vf is High.
The change to the level triggers the High level for the preset peak current conduction time Tp. During the period from time t1 to time t2 when the first pulse period signal ATf is at the high level, as shown in FIG.
The first base current AIb can be supplied during the period from time t2 to time t3 when the peak current AIp is supplied.

As shown in FIG. 3E, the second pulse period signal BTf is a signal that is synchronized with the first pulse period signal ATf and has a period n times as long. During the period from time t1 to time t2 when the second pulse period signal BTf is at the high level, the second peak current BIp is supplied, and during the period from time t2 to t6 when the second pulse period signal BTf is at the low level, the second pulse
Base current BIb (second base current BIb1 of normal value)
Or, the second base current BIb2 having a value larger than the normal value)
Is energized. Further, the second base current setting signal BIb shown in FIG. 5F has a second value larger than the normal value when the first pulse period signal ATf shown in FIG. The base current setting signal BIb2 becomes Lo
When at the w level, the second base current setting signal B having the normal value
Ib1. By this signal BIb, the second base current BIb2 having a larger value than the normal value or the second base current BIb1 having the normal value is supplied as the second base current BIb.

[0034]

In the prior invention, as described above, the first peak current conduction time ATp can be set to an arbitrary value by the peak current conduction time setting signal Tp described above with reference to FIG. it can. However, the second peak current conduction time BTp always has the same value as the first peak current conduction time ATp. As described above, the cycle of the second welding current BIw is the first welding current A
It can always be set to only an integral multiple (magnification n) of the period of Iw.

In the multi-electrode pulse arc welding method,
Depending on the requirements of the shape of the work to be welded, welding conditions, etc., different types, diameters, and the like of the first welding wire and the second welding wire may be used. For example, a YGW15 for steel having a diameter of 1.6 [mm] is used as the first welding wire.
(JIS standard), the diameter of the second welding wire is 1.
A 2 [mm] YGW18 for steel (JIS standard) may be used. In pulse arc welding, generally, an appropriate value of the peak current conduction time is determined according to the type and diameter of the welding wire. Therefore, as mentioned above,
If the type, diameter, etc., of the first welding wire and the second welding wire are different, the first peak current conduction time AT
It is necessary to set p and the second peak current conduction time BTp to different appropriate values. However, as described above, in the prior invention, the first peak current conduction time ATp
And the second peak current conduction time BTp cannot be set to different values. Therefore, one or both of them are set to the peak current energizing time that is not an appropriate value, and the droplet transfer does not become a stable state of one droplet per pulse, so that the amount of spatters generated increases and the bead appearance also increases. become worse.

Furthermore, it is necessary to set the average value of the first welding current AIw and the average value of the second welding current BIw to arbitrary values, respectively, according to the shape of the workpiece and welding conditions. However, as described above, in the prior application, the cycle of the second welding current BIw can be set only to an integral multiple of the cycle of the first welding current AIw. The average value of BIw cannot be set to an arbitrary value. For example, when the average value of the first welding current AIw is set to 300 [A], when the magnification n = 2, the average value of the second welding current BIw is 150 [A], and when the magnification n = 3. Time is 100
[A]. At this time, the second value larger than the normal value
The influence of the application of the base current BIb2 on the average value is not significant, so that the influence is ignored. In the above case, the average value of the second welding current BIw is set to 120 [A].
I cannot set it even if I want to. For this reason, the range of application of the multi-electrode pulse arc welding control method according to the invention of the prior application to implementation is limited.

Therefore, the present invention provides a multi-electrode pulse arc welding which can suppress the instability of the arc generation state due to the mutual interference of arcs, which is an effect of the prior application, and can solve the above-mentioned problems of the prior application. A control method is provided.

[0038]

According to the first aspect of the present invention, as shown in FIG. 6, a first welding wire A1 and a second welding wire electrically insulated from one welding torch 4 are mutually isolated. The wire B1 is fed at a preset feed rate, and the first welding wire A1 is supplied with a first peak current AIp and a first base current AIb. In addition to repeating the energization of the first welding wire B1, the energization of the second welding current Bp and the energization of the second base current BIb as one cycle are repeated in the second welding wire B1. In the multi-electrode pulse arc welding control method of generating and welding two arcs A3 and B3 between the welding wire A1 and the second welding wire B1 and the workpiece 2, the second welding wire B1 ,Up During the period from the start of the energizing period of the first peak current AIp to the elapse of the preset delay time Tod, the second base current BIb2 having a value larger than the normal value set in advance is energized. To the end of the energization period of the first peak current AIp, the second peak current BIp is energized, and the energization period of the first base current AIb is set to a predetermined normal value of the second current. This is a multi-electrode pulse arc welding control method for supplying a base current BIb1.

According to the invention of claim 2 at the time of filing, as shown in FIG. 7, a first welding wire A1 and a second welding wire B1 which are electrically insulated from one welding torch 4 are preset. The first welding wire A1 is repeatedly supplied with the first peak current AIp and supplied with the first base current AIb in one cycle. At the same time, the second welding wire B1 is repeatedly supplied with a second peak current BIp and a second base current BIb in one cycle, and is repeatedly supplied to the first welding wire A1 and the second welding current A1. Second
Arc A between the welding wire B1 and the workpiece 2
In the multi-electrode pulse arc welding control method for generating and welding B3 and B3, the second welding wire B1 is
During the period from the start of the first energization period of the first peak current AIp to the elapse of the preset delay time Tod, the second base current BIb2 having a value larger than the preset normal value is energized. The second peak current BIp is energized during the period from the elapsed time to the end of the energization period of the first peak current AIp, and the energization period of the first base current AIb is set to a predetermined normal value. The second
Then, during the second energization period of the first peak current AIp, the second base current BIb2 having a value larger than the normal value is energized, and the first base current AIb1 is energized. Is a multi-electrode pulse arc welding control method in which the second base current BIb1 having the normal value is supplied.

The invention of claim 3 at the time of filing is shown in FIGS.
As shown in FIG. 1, a first welding wire A1 and a second welding wire B1 which are electrically insulated from each other are fed at a preset feeding speed from one welding torch 4, and the first welding wire is supplied. A1 repeats energization in which one cycle of the energization of the preset first peak current AIp and the energization of the preset first base current AIb are repeated.
Of the second peak current B set in advance to the welding wire B1 of FIG.
The energization of Ip and the energization of the second base current BIb is repeated as one cycle, and two arcs A3 are provided between the first welding wire A1 and the second welding wire B1 and the workpiece 2. In the multi-electrode pulsed arc welding control method for generating and welding B3 and B3, the second welding wire B
1, the period from the start of the first energization period of the first peak current AIp to the elapse of the preset delay time Tod is the second base current having a value larger than the preset normal value. BIb2 is energized, and the second peak current BIp is energized during the period from the lapse of time to the end of the energization period of the first peak current AIp.
During the energizing period of the base current AIb, the second base current BIb1 having a normal value set in advance is applied, and then the energizing period of the first peak current AIp for the second time is set to a value larger than the normal value. The second base current BIb2 is energized, and the second base current BIb1 having the normal value is energized during the energization period of the first base current AIb.
This is a multi-electrode pulse arc welding control method in which the same energization as in the second time is repeated up to the n-th time with the magnification n being an integer, and the first to n-th energizations are repeated as one set to energize. .

In the invention of claim 4 at the time of filing, as shown in FIGS. 11 and 12, the period from the start of the energizing period of the first peak current AIp to the elapse of the delay time Tod is a predetermined normal period. A multi-electrode pulse arc welding control method according to claim 1, 2, or 3 at the time of filing the application of applying a second base current BIb1 having a value.

According to the invention of claim 5 at the time of filing, as shown in FIG. 14, a first welding wire A1 and a second welding wire B1 which are electrically insulated from one welding torch 4 are set in advance. At a predetermined feeding speed, and a first peak current AIp set in advance to the first welding wire A1.
And a predetermined first base current AIb are repeated as one cycle, and the second welding wire B1 is supplied with a second predetermined peak current BIp and a second base current AIb. The energization with the current BIb as one cycle is repeated, and two arcs A3 and B3 are generated between the first welding wire A1 and the second welding wire B1 and the workpiece 2 to perform welding. In the multi-electrode pulse arc welding control method, in the second welding wire B1,
The period from the start of the first energization period of the first peak current AIp to the elapse of the preset delay time Tod is a predetermined normal value of the second base current BI.
b1 and the first peak current A
The second peak current BIp is supplied until the end of the current supply period of Ip, the second base current BIb1 having the normal value is supplied during the supply period of the first base current AIb. In the second energizing period of the first peak current AIp and the energizing period of the first base current AIb, the second base current BIb1 having the normal value is energized, and a magnification which is an integer of 2 or more set in advance. n
This is a multi-electrode pulse arc welding control method in which the same energization as the first time is repeated up to the n-th time, and the first to n-th currents are repeatedly applied as a set.

As shown in FIG. 14, the invention of claim 6 at the time of filing applies a first peak rise time ATu and a preset first peak rise time ATu in the conduction period ATp of the first peak current AIp. Claim 1 or Claim at the time of filing, wherein a falling time ATd is provided, and a second peak rising time BTu and a second peak falling time BTd set in advance in the conduction period BTp of the second peak current BIp are provided. Item 2
Or a multi-electrode pulsed arc welding control method according to claim 3 or claim 4 or claim 5.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 6 is a current waveform diagram showing a first embodiment of the present invention, and FIG. 6A shows the time of a first welding current AIw. FIG. 7B shows a change over time of the second welding current BIw. Hereinafter, description will be made with reference to FIG.

In the first embodiment, a first peak current AIp is supplied to the first welding wire during a period from time t1 to time t2 (first peak current supply time ATp).
During the period from time t2 to time t3, the first base current AIb is supplied. On the other hand, in the second welding wire, the period from the start time (time t1) of the energization period of the first peak current AIp to the elapse of the preset delay time Tod (time t12) is larger than the normal value. Value of the second base current BIb2
During the period from the elapsed time (time t12) to the end of the current application period of the first peak current AIp (time t3), the second peak current BIp is applied.
During the current supply period of the base current AIb, the second base current BIb1 having a normal value is supplied.

According to the multi-electrode pulsed arc welding control method of the first embodiment described above, it is possible to suppress the instability of the arc generation state due to the mutual interference of the arcs. In other words, during the period from time t1 to t12, the second arc is supplied with a base current BIb2 having a larger value than the normal value in order to suppress the mutual interference of the arcs caused by the large peak current AIp for energizing the first arc. Is turned on. At time t12
During the period from t2 to t2 and t2 to t3, the peak current or the base current having the same value is supplied to both arcs. Therefore, as described above, there is no influence on the arc generation state due to the mutual interference of the arcs.

Further, in the control method of the first embodiment, by changing the set value of the delay time Tod, the second peak current conduction time BTp is set to a value different from the first peak current conduction time ATp. Can be set to
Also, by changing the delay time Tod,
The average value of the second welding current BIw is referred to as the first welding current AIw.
Can be set to a value different from the average value of.

In FIG. 6, a method of starting the second peak current conduction time BTp from the time t1 can be considered. In this case, before and after the end of the second peak current conduction time BTp, the second
At the time of the separation, a large peak current AIp is applied to the first arc, so that the droplets are not smoothly separated due to the interference of the arc, and large droplets are formed. Is generated. Therefore, this method cannot be adopted.

[Second Embodiment] FIG. 7 is a current waveform diagram showing a second embodiment of the present invention, and FIG. 7A shows a time change of the first welding current AIw. FIG. 7B shows a time change of the second welding current BIw. Hereinafter, description will be made with reference to FIG.

In the second embodiment, the first peak current AIp is applied to the first welding wire during the period from time t1 to time t2 (first peak current application time ATp).
During the period from time t2 to time t3, the first base current AIb is supplied. Subsequently, during the period from time t3 to time t5, the same energization as described above is repeated. On the other hand, the second welding wire normally has a period from the start time (time t1) of the first energization period of the first peak current AIp to the elapse time (time t12) of the preset delay time Tod. The second base current BIb2 having a value larger than the value is supplied, and the above-mentioned elapsed time (time t
In the period from 12) to the end of the current supply period of the first peak current AIp (time t2), the second peak current BI
p, and the energization period (time t2 to t3) of the first base current AIb is the second base current BIb1 of the normal value.
And then the second peak current AI
During the energization period of p (time t3 to t4), the second base current BIb2 having a value larger than the normal value is applied, and the energization period of the first base current AIb (time t4 to t5) is set to the normal value. The second base current BIb1 is supplied.

[Third Embodiment] FIG. 8 is a current waveform diagram showing a third embodiment of the present invention, and FIG. 8A shows a time change of the first welding current AIw. FIG. 7B shows a time change of the second welding current BIw. Hereinafter, description will be made with reference to FIG.

In the third embodiment, the first welding wire is supplied with the first peak current AIp during the period from time t1 to time t2 (first peak current conduction time ATp), and is supplied from time t2 to time t3. During the period, the first base current AIb is supplied. Subsequently, during the period from time t3 to t6, the same energization as described above is repeated. On the other hand, the second welding wire normally has a period from the start time (time t1) of the first energization period of the first peak current AIp to the elapse time (time t12) of the preset delay time Tod. The second base current BIb2 having a value larger than the value is supplied, and the above-mentioned elapsed time (time t
In the period from 12) to the end of the current supply period of the first peak current AIp (time t2), the second peak current BI
p, and the energization period (time t2 to t3) of the first base current AIb is the second base current BIb1 of the normal value.
And then the second peak current AI
During the energization period of p (time t3 to t4), the second base current BIb2 having a value larger than the normal value is applied, and the energization period of the first base current AIb (time t4 to t5) is set to the normal value. The second base current BIb1 is applied, and the same energization as the second is repeated up to the n-th time by a preset integer n which is an integer of 2 or more, and the first to n-th energizations are performed for 1 time. Energize repeatedly as a set.
FIG. 3 illustrates a case where the magnification n = 3.

According to the multi-electrode pulse arc welding control method of the third embodiment described above, as in the case of FIG. 6, the arc generation state does not become unstable due to the mutual interference of the arcs.
Further, in the control method according to the third embodiment, similarly to the case of FIG. 6, by changing the set value of the delay time Tod, the second peak current conduction time BTp is changed to the first peak current conduction time. It can be set to a value different from the time ATp. Further, by changing the magnification n and the delay time Tod in combination, the average value of the second welding current BIw can be set to an arbitrary value different from the average value of the first welding current AIw.

FIG. 9 is a block diagram showing a circuit configuration of a welding apparatus for implementing the multi-electrode pulse arc welding control method according to the third embodiment. 4, the same circuit blocks as those in FIG. 4 described above are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, the delay time setting circuit TO which is a circuit block different from FIG.
D, the delay circuit OD, and the first AND circuit AND1 will be described with reference to FIG.

The delay time setting circuit TOD outputs a delay time setting signal Tod. The delay circuit OD is triggered by the change of the second pulse cycle signal BTf having a cycle n times the cycle of the first pulse cycle signal ATf from the Low level to the High level, and the delay time setting is performed from that time. The delay signal Od which is at the Low level for a period determined by the signal Tod is output. The first AND circuit AND1 performs a logical product (AND) of the second pulse period signal BTf and the delay signal Od, and outputs a switching signal Ad1. By this switching signal Ad1, the second peak current setting signal BI
p and the second base current setting signal BIb are switched. Although the magnification setting circuit NS and the delay time setting circuit TOD are provided in the second welding power supply in FIG. 2, these circuits may be provided outside the power supply. Further, the magnification setting signal n and the delay time setting signal Tod may be set by a communication signal from the welding robot control device.

FIG. 10 is a timing chart of each signal in the welding apparatus of the present invention described above with reference to FIG. FIG. 3A shows the time change of the first welding current AIw, FIG. 3B shows the time change of the second welding current BIw, and FIG. 3C shows the first pulse. FIG. 4D shows the time change of the periodic signal ATf, FIG. 4D shows the time change of the second pulse period signal BTf, and FIG. 5E shows the time change of the delay signal Od. FIG. 7F shows the change over time of the switching signal Ad1. Hereinafter, description will be made with reference to FIG.

As shown in FIG. 10D, the cycle of the second pulse cycle signal BTf is three times (multiplier n) the cycle of the first pulse cycle signal ATf shown in FIG. As shown in FIG. 9E, the delay signal Od is at the time t when the second pulse period signal BTf changes to the High level.
It is at the Low level from 1 to the time point when the delay time Tod has elapsed (time t12). As shown in FIG. 9F, the switching signal Ad1 is a signal of the logical product (AND) of the second pulse period signal BTf and the delay signal Od, and is switched at time t12.
It is at the high level for a period from t2. This switching signal Ad1
Is a second peak current conduction time BTp during a High level period, and is a conduction period of a second base current BIb during a Low level period.

[Fourth Embodiment] FIG. 11 is a current waveform diagram showing a fourth embodiment of the present invention.
Shows the time change of the first welding current AIw, and FIG. 7B shows the time change of the second welding current BIw. Hereinafter, description will be made with reference to FIG.

In the figure, the period from time t1 to time t12 is different from the case of FIGS. 6 to 8 described above in that the second base current BIb2 having a larger value than the normal value is used instead of the second base current BIb2 having the normal value. The current BIb1 is supplied. The other periods are the same as those in FIG.

During the period from time t1 to time t12, a large peak current flows through the first arc and a normal base current flows through the second arc, as described above. The shape of the second arc is deformed by mutual interference of the arcs. However, at time t12 immediately after that, since a large peak current flows, the deformation of the second arc is corrected instantaneously, and the influence on the arc generation state is small. Although the case corresponding to FIG. 8 described above has been described in the above case, the same applies to the case corresponding to FIGS. 6 and 7.

FIG. 12 is a block diagram showing a circuit configuration of a welding apparatus for implementing the above-described multi-electrode pulse arc welding control method according to the fourth embodiment. In the figure,
The same circuit blocks as those in FIG. 9 described above are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, a second AND circuit A which is a circuit block different from that shown in FIG.
ND2 will be described with reference to FIG.

The second AND circuit AND2 calculates a logical product (AND) of the first pulse period signal ATf and the delay signal Od.
And outputs a base current switching signal Ad2. The base current switching signal Ad2 switches between the second base current setting signal BIb2 having a value larger than the normal value and the second base current setting signal BIb1 having the normal value.

FIG. 13 is a timing chart of each signal in the welding apparatus of FIG. 12 described above. FIG. 3A shows the time change of the first welding current AIw, FIG. 3B shows the time change of the second welding current BIw, and FIG. 3C shows the first pulse. FIG. 4D shows a time change of the periodic signal ATf, and FIG.
FIG. 9E shows the time change of Tf, and FIG.
d shows a time change, and FIG. 7F shows the switching signal Ad1.
(G) shows a time change of the base current switching signal Ad2. In the figure, FIG.
Since FIG. 10F is the same as FIG. 10 described above, the description is omitted. Hereinafter, FIG. 1G will be described with reference to FIG.

As shown in FIG. 10G, the base current switching signal Ad2 is composed of the first pulse period signal ATf and the delay signal O.
d is a signal of a logical product (AND) with time t.
The period 12 is at the low level. While the base current switching signal Ad2 is at the high level, the second base current setting signal BIb becomes the second base current setting signal BIb2 having a value larger than the normal value, and during the low level, the second base current setting signal BIb2 has the normal value. This becomes the base current setting signal BIb1. Due to this signal, the period from time t1 to t12 is different from that in FIGS. 6 to 8 described above, and the second base current B having the normal value is used.
Ib1 is energized.

[Fifth Embodiment] FIG. 14 is a current waveform diagram showing a fifth embodiment of the present invention.
Shows the time change of the first welding current AIw, and FIG. 7B shows the time change of the second welding current BIw. Hereinafter, description will be made with reference to FIG.

In the figure, at times t3 to t4 and t5 to t5
During the period of t52, unlike the case of FIG. 11 described above, the second base current BIb1 having the normal value is supplied instead of the second base current BIb2 having the larger value than the normal value. The other periods are the same as those in FIG.

The above time t3 to t4 and t5 to t5
During the period 2, since the first arc is energized with a large peak current and the second arc is energized with a normal base current, as described above, the second arc is The shape is deformed by mutual interference. However, since the frequency is low and the time occupying the arc generation time is short, the influence on the arc generation state is small.

[Sixth Embodiment] FIG. 15 is a current waveform diagram showing a sixth embodiment of the present invention.
Shows the time change of the first welding current AIw, and FIG. 7B shows the time change of the second welding current BIw. Hereinafter, description will be made with reference to FIG.

FIG. 9 shows that the first peak rise time ATp is added to the first peak current conduction time ATp in FIG.
u and a first peak fall time ATd, and a second peak rise time BT is added to the second peak current conduction time BTp.
u and a second peak fall time ATd. Except for this, the configuration is the same as that of FIG. Although FIG. 8 illustrates the case corresponding to FIG. 8, the same applies to the cases corresponding to FIG. 6, FIG. 7, FIG. 11, and FIG.

[0070]

According to the present invention, in the multi-electrode pulse arc welding method, the instability of the arc generation state caused by the mutual interference of two arcs can be suppressed,
The duration of the peak current flowing through the two arcs can be set to an appropriate value in accordance with the type, diameter, etc. of each welding wire. Since the bead becomes stable, a beautiful bead appearance with a small amount of spatter is obtained, and good welding quality can be obtained.

Further, in the present invention, by setting the magnification n and the delay time Tod, the average value of the welding current for energizing the first arc and the average value of the welding current for energizing the second arc can be respectively determined. Can be set to any value. Therefore, by setting the average value of the welding current to an appropriate value in accordance with the shape of the workpiece, welding conditions, and the like, good welding quality can be obtained. Also,
As a result, the applicable range of the present invention is widened.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a conventional multi-electrode pulse arc welding apparatus.

FIG. 2 is a schematic view of an arc generating unit for explaining mutual interference between two arcs.

FIG. 3 is a current / voltage waveform diagram of a conventional technique.

FIG. 4 is a block diagram of a conventional device.

FIG. 5 is a timing chart of each signal in a conventional device.

FIG. 6 is a current waveform diagram showing the first embodiment of the present invention.

FIG. 7 is a current waveform diagram showing a second embodiment of the present invention.

FIG. 8 is a current waveform diagram showing a third embodiment of the present invention.

FIG. 9 is a block diagram of a welding device according to a third embodiment of the present invention.

FIG. 10 is a timing chart of each signal in the welding device according to the third embodiment of the present invention.

FIG. 11 is a current waveform diagram showing a fourth embodiment of the present invention.

FIG. 12 is a block diagram of a welding device according to a fourth embodiment of the present invention.

FIG. 13 is a timing chart of each signal in the welding device according to the fourth embodiment of the present invention.

FIG. 14 is a current waveform diagram showing a fifth embodiment of the present invention.

FIG. 15 is a current waveform diagram showing a sixth embodiment of the present invention.

[Explanation of symbols]

2 Workpiece 21 Weld pool 4 Welding torch A1 First welding wire A3 First arc A41 First contact tip Ad1 Switching signal Ad2 Base current switching signal AFX, BFX Contraction force by arc AFZ, BFZ Force by magnetic field AIB 1 base current setting circuit AIb first base current (setting signal) AIP first peak current setting circuit AIp first peak current (setting signal) AIsc first current control setting signal AIw first welding current AND1 1 AND circuit AND2 2nd AND circuit APS First welding power supply ASW First switching circuit ATd First peak fall time ATf First pulse period (signal) ATp First peak current conduction time ATu First peak rise time AVb First base voltage AVp First peak voltage AVw First welding Pressure AWC First feed control circuit AWc First feed control signal AWF First wire feeder AWS First feed speed setting circuit AWs First feed speed setting signal B1 Second welding wire B3 Second arc B41 Second contact tip BIB Second base current setting circuit BIb Second base current (setting signal) BIb1 Second base current (setting signal) of normal value BIb2 Second base current of larger value than normal value 2 base current (setting signal) BIP 2nd peak current setting circuit BIp 2nd peak current (setting signal) BIsc 2nd current control setting signal BIw 2nd welding current BPS 2nd welding power supply BSW 2nd BTd Second peak fall time BTf Second pulse cycle (signal) BTp Second peak current conduction time BTu Second peak rise time BVb Second Base voltage BVp second peak voltage BVw second welding voltage BWC second feed control circuit BWc second feed control signal BWF second wire feeder BWS second feed speed setting circuit BWs 2 feed speed setting signal EI current error amplification circuit Ei current error amplification signal EV voltage error amplification circuit Ev voltage error amplification signal ID current detection circuit Id current detection signal INV output control circuit MC modulation circuit MM mono multivibrator n magnification (setting Signal) NS magnification setting circuit OD delay circuit Od delay signal TC period conversion circuit TOD delay time setting circuit Tod delay time (setting signal) TP peak current conduction time setting circuit Tp peak current conduction time setting signal VD voltage detection circuit Vd voltage detection signal VF V / F conversion circuit Vf V / F conversion signal VS Voltage setting circuit Vs Voltage setting Constant signal Wc Feed control signal

Claims (6)

[Claims] 1. A first welding wire and a second welding wire, which are electrically insulated from each other, are fed from a single welding torch at a feed rate set in advance. The energization with the set first peak current energization and the preset first base current energization as one cycle is repeated, and the second welding current with the predetermined second peak current energization is repeated. A multi-electrode pulse that repeats energization with one cycle of energization of the second base current to generate two arcs between the first welding wire, the second welding wire, and the workpiece to be welded. In the arc welding control method, in the second welding wire, a period from a start time of a current supply period of the first peak current to a lapse of a predetermined delay time is a value larger than a normal value set in advance. Second The base current is energized, the period from the elapsed time until the end of the conduction period of the first peak current is the second
A multi-electrode pulse arc welding control method in which a peak current is supplied, and the second base current having a preset normal value is supplied during the supply period of the first base current. 2. A first welding wire and a second welding wire, which are electrically insulated from each other, are fed from a single welding torch at a feed rate set in advance, respectively. The energization with the set first peak current energization and the preset first base current energization as one cycle is repeated, and the second welding current with the predetermined second peak current energization is repeated. A multi-electrode pulse that repeats energization with one cycle of energization of the second base current to generate two arcs between the first welding wire, the second welding wire, and the workpiece to be welded. In the arc welding control method, a period from a start time of a first energization period of the first peak current to a lapse of a preset delay time of the second welding wire is longer than a preset normal value. Large value The second base current is supplied, and the second peak current is supplied during a period from the elapse time to the end of the first peak current supply period, and the first base current supply period is provided. Energizing the second base current having a preset normal value, and subsequently energizing a second base current having a value larger than the normal value during a second energizing period of the first peak current, A multi-electrode pulse arc welding control method in which the second base current having the normal value is supplied during the first base current conduction period. 3. A first welding wire and a second welding wire, which are electrically insulated from each other, are fed from a single welding torch at a preset feeding speed, and the first welding wire is supplied to the first welding wire in advance. The energization with the set first peak current energization and the preset first base current energization as one cycle is repeated, and the second welding current with the predetermined second peak current energization is repeated. A multi-electrode pulse that repeats energization with one cycle of energization of the second base current to generate two arcs between the first welding wire, the second welding wire, and the workpiece to be welded. In the arc welding control method, a period from a start time of a first energization period of the first peak current to a lapse of a preset delay time of the second welding wire is longer than a preset normal value. Large value The second base current is supplied, and the second peak current is supplied during a period from the elapse time to the end of the first peak current supply period, and the first base current supply period is provided. Energizing the second base current having a preset normal value, and subsequently energizing a second base current having a value larger than the normal value during a second energizing period of the first peak current, During the energization period of the first base current, the second base current having the normal value is energized, and the energization similar to the second energization is repeated until the n-th energization with a predetermined magnification n which is an integer of 2 or more. A multi-electrode pulse arc welding control method in which the first to n-th energizations are repeatedly performed as a set and energization is repeated. 4. The first base current of a predetermined normal value is supplied during a period from the start of the current supply period of the first peak current to the elapse of the delay time.
Or the multi-electrode pulse arc welding control method according to claim 3. 5. A first welding wire and a second welding wire, which are electrically insulated from each other, are fed from a single welding torch at a feed rate set in advance, respectively. The energization with the set first peak current energization and the preset first base current energization as one cycle is repeated, and the second welding current with the predetermined second peak current energization is repeated. A multi-electrode pulse that repeats energization with one cycle of energization of the second base current to generate two arcs between the first welding wire, the second welding wire, and the workpiece to be welded. In the arc welding control method, in the second welding wire, a period from a start time of a first energizing period of the first peak current to a lapse of a preset delay time is a normal value of a preset normal value. Second bais Current is supplied, the second peak current is supplied during a period from the elapsed time to the end of the supply period of the first peak current, and the supply period of the first base current is set to the normal value of the normal value. 2 for the second period of the first peak current and for the second period of the first base current, the second base current having the normal value is passed, and Magnification n which is an integer of 2 or more
A multi-electrode pulse arc welding control method in which the same energization as in the second cycle is repeated up to the n-th cycle, and the first to n-th cycles are repeatedly performed as a set. 6. A preset first peak rise time and a preset first peak fall time are provided in a current supply period of a first peak current, and a predetermined first peak fall time is set in a current supply period of a second peak current. 3. The method according to claim 1, wherein a second peak rise time and a second peak fall time set in advance are provided.
Or the multi-electrode pulse arc welding control method according to claim 3 or 4 or 5.