JP2023041463A - Two wire welding starting method and welding apparatus - Google Patents

Abstract

To provide a two wire welding starting method and a welding apparatus which can sense contacting of a filler wire with an object to be welded to accurately control a timing of feeding the filler wire, without preparing a power source different from a welding power source.SOLUTION: A two wire welding starting method, which makes a welding wire advance in a welding direction while generating an arc between a weld wire of a consumable electrode and an object to be welded to form a weld pool, and supplies a filler wire to the weld pool from a rear side in the welding direction, feeds the filler wire toward the object to be welded, measures a load of feeding the filler wire, determines whether the filler wire contacts the object to be welded or not on the basis of the measured load of feeding, and when determining that the filler wire contacts the object to be welded, pulls back the filler wire from the object to be welded by a predetermined quantity, and feeds the filler wire to the object to be welded at a timing and a feeding speed which are in accordance with the predetermined quantity after starting firing of the arc.SELECTED DRAWING: Figure 4

Description

The present invention relates to a two-wire welding starting method and a welding control device.

A two-wire welding method is known in which an arc is generated between a welding wire as a consumable electrode and a base material to form a molten pool, and a filler wire is fed to the molten pool in a short-circuited state for welding. there is

In Patent Document 1, in a method for starting two-wire welding, the filler wire is brought close to the object to be welded while a voltage is applied between the filler wire and the object to be welded, and the filler wire and the object to be welded are separated from each other. A method is disclosed to stop the filler wire from approaching and away from the weld object when the wire is energized.

JP 2009-106985 A

However, in the conventional two-wire welding starting method, it is necessary to apply a voltage between the filler wire and the welding object in order to detect the contact between the filler wire and the welding object, and the welding power source is separate from the welding power source. It was necessary to prepare a device for applying voltage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a 2-wire welding apparatus capable of detecting contact between a filler wire and an object to be welded and accurately controlling the feed timing of the filler wire without preparing a power source separate from the welding power source. To provide a starting method and a welding device.

A method for starting two-wire welding according to an aspect of the present disclosure includes advancing the welding wire in a welding direction while forming a molten pool by generating an arc between a welding wire of a consumable electrode and an object to be welded, A method for starting two-wire welding in which a filler wire is supplied to the molten pool from behind in the welding direction, wherein the filler wire is fed toward the object to be welded, and the feed load of the filler wire is measured. The presence or absence of contact between the filler wire and the object to be welded is determined based on the feed load obtained, and when it is determined that the filler wire has contacted the object to be welded, the filler wire is removed from the object to be welded. After a fixed amount of pullback, arc ignition is started, or after the welding wire and the filler wire start to advance in the welding direction, the filler wire is fed to the welding object at a timing and a feeding speed according to the predetermined amount. supply.

A welding apparatus according to an aspect of the present disclosure generates an arc between a welding wire of a consumable electrode and a welding object to form a molten pool while advancing the welding wire in the welding direction, and from behind the welding direction. A welding apparatus for supplying a filler wire to the molten pool, comprising: a filler wire feed control circuit for controlling feeding of the filler wire; and a measurement circuit for measuring the feeding load of the filler wire, A filler wire feed control circuit determines whether or not the filler wire is in contact with the object to be welded based on the feed load measured by the measurement circuit, and determines whether the filler wire is in contact with the object to be welded. If determined, the filler wire is pulled back from the object to be welded by a predetermined amount, and after the ignition of the arc is started or after the welding wire and the filler wire start to advance in the welding direction, timing and Feeding the filler wire to the object to be welded at a feeding speed.

According to the present disclosure, it is possible to detect the contact between the filler wire and the object to be welded without preparing a power source separate from the welding power source, and to accurately control the feeding timing of the filler wire.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one structure of the welding apparatus which concerns on this embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows one structure of the welding apparatus which concerns on this embodiment. It is a flowchart which shows the procedure of the starting method of 2 wire welding which concerns on this embodiment. 4 is a timing chart showing a method for starting two-wire welding according to the embodiment;

A specific example of a method for starting two-wire welding and a welding control device according to an embodiment of the present invention will be described below with reference to the drawings. The present invention is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described based on the drawings showing its embodiments.
(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration example of a welding device, and FIG. 2 is a block diagram showing a configuration example of the welding device. The welding apparatus according to the present embodiment generates an arc 9 between a welding wire WA as a consumable electrode and a base material (workpiece to be welded) 6 to form a molten pool WP, and a filler wire WB as a filler material. to the weld pool WP.

The welding device includes a welding robot 10a, a welding power source 1, a control device 10, and a shield gas supply section (not shown). Welding robot 10 a is provided with welding torch 2 , welding wire feed roller 3 , liner 4 for filler wire WB, and filler wire feed roller 5 . In FIG. 1, a thick line connecting the welding power source 1 and the welding robot 10a is a power supply cable, and a thin line is a control communication line.

Control device 10 sets welding conditions for welding power source 1 and controls the operation of welding power source 1 . Further, the control device 10 controls the operation of the welding robot 10a by outputting an operation control signal to the welding robot 10a.

The welding robot 10a has a base fixed to a suitable location on the floor. A plurality of arms are rotatably connected to the base through shafts. A welding torch 2 and a liner 4 are held at the tip portion of the arm connected to the tip side. A servomotor is provided at the linking portion of the arm, and each arm rotates around the shaft portion by the rotational driving force of the servomotor. Rotation of the servomotor is controlled by the controller 10 . By rotating each arm, the control device 10 can move the welding torch 2 and the liner 4 up, down, forward, backward, leftward, and rightward with respect to the base material 6 . An encoder for outputting a signal indicating the rotational position of the arm to the controller 10 is provided at the connecting portion of each arm. Recognize the position and orientation of 4.

The welding torch 2 is made of a conductive material such as a copper alloy, and has a cylindrical contact tip that guides the welding wire WA to the base material 6 and supplies the welding current I required to generate the arc 9 . The contact tip comes into contact with the welding wire WA passing therethrough and supplies the welding current I to the welding wire WA. The welding torch 2 has a hollow cylindrical shape surrounding the contact tip and has a nozzle for injecting shielding gas.

The welding wire WA is, for example, a solid wire, has a diameter of 0.9 mm or more and 1.6 mm or less, and functions as a consumable electrode.

The welding wire feed roller 3 is rotated by the output torque of the welding wire feed motor WM. The welding wire feed motor WM is driven by a welding wire drive circuit WMD. The welding wire WA is fed to the welding torch 2 by the rotation of the welding wire feed roller 3, and is supplied with power from the power source 11 via the contact tip. An arc 9 is generated between the welding wire WA to which power is supplied and the base material 6 to form a molten pool WP in the base material 6 . For buried arc welding, the feeding speed of the welding wire WA is, for example, approximately 5-100 m/min.

The operation of welding wire drive circuit WMD is controlled by welding wire feed control circuit WCT. That is, the welding wire feed control circuit WCT controls the feed start, feed stop, and feed speed of the welding wire WA. A welding wire feed speed setting circuit WR for setting the feed speed of the welding wire WA is connected to the welding wire feed control circuit WCT. Welding wire feed speed setting circuit WR outputs a signal indicating a feed speed corresponding to welding current I to welding wire feed control circuit WCT. Welding wire feed control circuit WCT controls the feed speed of welding wire WA according to the signal.

The liner 4 is a cylindrical member that guides the filler wire WB to the base material 6 . The filler wire WB passes through the inside of the liner 4 and is fed to the base material 6 .
In the welding power source 1 that performs buried arc welding, the liner 4 and the welding torch 2 have a feed destination of the filler wire WB to the base material 6 and a feed destination of the welding wire WA to the base material 6 that is about 6 mm or more. isolated. In other words, the distance between the liner 4 and the welding torch 2 is such that the filler wire WB can enter the molten pool WP at a point separated from the arc 9 generated between the welding wire WA and the base material 6. be. The filler wire WB is melted not by the arc 9 but by the heat of the molten pool WP.

The filler wire feeding roller 5 is rotated by the output torque of the filler wire feeding motor FM. The filler wire feed motor FM is driven by a filler wire driving circuit FMD. The filler wire WB is fed to the liner 4 by the rotation of the filler wire feeding roller 5 . The filler wire WB guided by the liner 4 enters the molten pool WP formed in the base material 6 and is melted by the heat of the molten pool WP.

The filler wire drive circuit FMD has a feeding load measuring circuit LD that measures the feeding load of the filler wire WB by detecting the current flowing through the filler wire feeding motor FM. The feed load is the feed resistance of the filler wire WB. The feed load measurement circuit LD outputs a signal indicating the measured feed load to the filler wire feed control circuit FCT.

The operation of the filler wire drive circuit FMD is controlled by the filler wire feed control circuit FCT. That is, the filler wire feed control circuit FCT controls the feed start, feed stop, and feed speed of the filler wire WB. A filler wire feeding speed setting circuit FR for setting the feeding speed of the filler wire WB is connected to the filler wire feeding control circuit FCT. The filler wire feed control circuit FCT also has a timer.
The filler wire feeding speed setting circuit FR outputs a signal indicating the feeding speed to the filler wire feeding control circuit FCT. The filler wire feed control circuit FCT receives a signal indicating the feed load of the filler wire WB output from the feed load measurement circuit LD, and determines whether the filler wire WB has come into contact with the base material 6 based on the signal. determine whether or not When starting two-wire welding, the filler wire feed control circuit FCT controls the feeding amount of the filler wire WB, that is, the filler wire protruding from the liner 4, based on the position where the filler wire WB and the base material 6 are in contact with each other. The distance between the WB and the base material 6 can be accurately recognized, and the timing at which the filler wire WB reaches the base material 6 matches the timing at which the molten pool WP reaches the feeding destination of the filler wire WB. Thus, the feeding timing and feeding speed of the filler wire WB can be controlled. Therefore, after the arc 9 is ignited and the welding torch 2 and the liner 4 start advancing in the welding direction, the molten pool WP formed in the base material 6 by the arc 9 reaches directly below the liner 4. , feeding of the filler wire WB can be controlled with high accuracy so that the filler wire WB enters the molten pool WP. In particular, in buried arc welding, which will be described later, more accurate control of the filler wire WB is required than in normal non-buried arc welding.

The welding power source 1 includes a power source section 11 that is connected to the contact tip of the welding torch 2 and the base material 6 via a power supply cable and that supplies a welding current I. The power supply unit 11 is a power supply with constant voltage characteristics, and includes a power supply circuit 11a that outputs a PWM-controlled DC current, a control circuit 11b, a voltage detection unit 11c, and a current detection unit 11d.

The voltage detector 11c detects the welding voltage V and outputs a voltage value signal Vd indicating the detected voltage value to the control circuit 11b.

The current detection unit 11d detects, for example, a welding current I supplied from the welding power source 1 to the welding wire WA via the welding torch 2 and flowing through the arc 9, and outputs a current value signal Id indicating the detected current value to the control circuit 11b. Output to

The welding power source 1 behaves as a power source with constant voltage characteristics. For example, the welding power source 1 stores external characteristics such that the decrease in the welding voltage V with respect to the increase in the welding current I of 100 A is 2 V or more and 20 V or less. The external characteristics may be different for each combination of set current and set voltage, or may be common.

The control circuit 11b operates with a constant voltage characteristic, and controls the operation of the power supply circuit 11a so that the power supply circuit 11a outputs a voltage corresponding to a current setting signal and an output voltage setting signal output from a setting circuit (not shown). It is a circuit that The control circuit 11b electronically controls the electric resistance R and the reactor L existing in the energization path of the welding power source 1 to achieve constant voltage characteristics.
The control circuit 11b outputs a voltage value signal Vd output from the voltage detection unit 11c, a current value signal Id output from the current detection unit 11d, and a current setting signal and an output voltage setting signal output from a setting circuit (not shown). and outputs the calculated difference signal Ei to the power supply circuit 11a. The difference signal Ei is a signal indicating the difference between the detected current value and the current value to be output from the power supply circuit 11a.

The power supply circuit 11a includes an AC-DC converter that converts alternating current into alternating current, an inverter circuit that converts the converted direct current into a desired alternating current by switching, a rectifier circuit that rectifies the converted alternating current, and the like. The power supply circuit 11a PWM-controls the inverter according to the differential signal Ei output from the control circuit 11b so that the differential signal Ei becomes smaller, and outputs the welding current I and the welding voltage V to the welding wire WA. As a result, a predetermined welding voltage V is applied between the base material 6 and the welding wire WA, and a welding current I is applied.

FIG. 3 is a flow chart showing the procedure of a method for starting two-wire welding according to this embodiment. It is assumed that a pair of base materials 6 to be joined by welding are placed in a welding device and various settings are made.

The filler wire feed control circuit FCT of the welding power source 1 starts feeding the filler wire WB (step S111). The feeding speed is not particularly limited, but it is desirable that the feeding speed is slower than that during the main welding.

Next, the filler wire feeding control circuit FCT measures the feeding load of the filler wire WB based on the signal output from the feeding load measuring circuit LD (step S112). Then, the filler wire feed control circuit FCT determines whether or not the feed load of the filler wire WB is less than the threshold (step S113). If it is determined that the feed load is less than the threshold, that is, if it is determined that the filler wire WB is not in contact with the base material 6 (step S113: YES), the process returns to step S112. When it is determined that the feed load is equal to or greater than the threshold value, that is, when it is determined that the filler wire WB is in contact with the base material 6 (step S113: NO), the filler wire feed control circuit FCT controls the feed load of the filler wire WB. Feeding is stopped, and the filler wire WB is pulled up by a predetermined amount (step S114).

Next, power supply unit 11 applies welding voltage V to welding wire WA (step S115), and welding wire feed control circuit WCT starts feeding welding wire WA (step S116). It is preferable that the feeding speed of the welding wire WA is slower than that during normal welding of the main welding.

Next, the control circuit 11b of the welding power source 1 determines whether or not the arc 9 has been ignited based on the detected welding current I (step S117). If it is determined that the arc 9 has not been ignited (step S117: NO), the welding power source 1 waits until the arc 9 is ignited. When the welding power source 1 determines that the arc 9 has been ignited (step S117), the welding robot 10a starts moving the welding torch 2 and the liner 4 with respect to the base material 6 (step S118).

Further, the filler wire feed control circuit FCT of the welding power source 1 counts the elapsed time from the start of ignition of the arc 9 or the start of movement of the welding torch 2 and liner 4 (step S119), and a predetermined time has elapsed. It is determined whether or not (step S120). When determining that the predetermined time has not elapsed (step S120: NO), the filler wire feed control circuit FCT returns the process to step S120. When it is determined that the predetermined time has passed (step S120: YES), the filler wire feeding control circuit FCT starts feeding the filler wire WB (step S121). Details of the feeding timing and feeding speed of the filler wire WB will be described later.

Next, the control circuit 11b and the welding wire feed control circuit WCT perform buried arc welding control by controlling the feed of the welding wire WA and the output of the power supply unit 11 based on the set welding conditions (step S122). ). Specifically, the welding wire feed control circuit WCT of the welding power source 1 drives the welding wire feed motor WM to feed the welding wire WA at a speed corresponding to the set current. In addition, the power supply unit 11 of the welding power source 1 detects the welding voltage V and the welding current I with the voltage detection unit 11c and the current detection unit 11d. The output of the power supply unit 11 is PWM-controlled so that it exists on the external characteristic line corresponding to .
The critical current at which a buried arc state can occur varies depending on the type of welding wire WA and shielding gas. When the welding conditions are set to 300 A or more, a buried arc state occurs. For buried arc welding, the feeding speed of the welding wire WA is, for example, approximately 5-100 m/min. The power supply unit 11 is preferably configured to have external characteristics such that a decrease in the welding voltage V with respect to an increase in the welding current I of 100 A is 2 V or more and 20 V or less. By setting the external characteristics of the power supply section 11 in this way, it becomes easy to maintain the buried arc state.

As described above, in buried arc welding using a shield gas containing argon, a high current with an average current of 300 A or more is supplied to the welding wire WA, and the welding wire WA is fed at about 5 to 100 m / min. In this case, a liquid column in which the molten wire is elongated is formed at the tip of the welding wire WA. Also, a concave molten pool WP made of the molten metal of the base material 6 and the welding wire WA is formed in the base material 6 . A bright arc 9 is formed between the relatively lower part of the liquid column and the concave weld pool WP. On the other hand, an arc 9 with relatively low brightness is formed between the relatively upper portion of the liquid column or the solid welding wire WA and the concave weld pool WP.
The buried arc 9 includes a quasi-buried arc state in which only the arc 9 generation point on the liquid column side enters the buried space in the recessed portion of the molten pool WP, and the welding wire WA or the arc 9 on the welding wire WA side. There is a fully buried arc condition that has entered the buried space up to the point of origin.

FIG. 4 is a timing chart showing a method for starting two-wire welding according to this embodiment. In FIG. 4, the charts lined up from top to bottom show changes over time in the feed load of the filler wire WB, the feed speed of the filler wire WB, the welding voltage V, the welding current I, the feed speed of the welding wire WA, and the welding speed. showing. Welding speed is the speed at which welding torch 2 and liner 4 move along the weld line.

At time t1, the filler wire feeding control circuit FCT starts feeding the filler wire WB. The feeding speed at this time is not particularly limited, but it is desirable that the feeding speed is slower than that during the main welding. As the filler wire WB is fed, the tip of the filler wire WB approaches the base material 6 . During this time, the filler wire feed control circuit FCT measures the feed load of the filler wire WB in the feed load measuring circuit LD.

Next, at time t2, when the filler wire WB comes into contact with the base material 6, the feeding load rises sharply. When the feed load exceeds the threshold, the filler wire feed control circuit FCT determines that the filler wire WB has come into contact with the base material 6, stops feeding the filler wire WB, and pulls up the filler wire WB. That is, the filler wire feeding control circuit FCT rotates the filler wire feeding roller 5 in the direction opposite to the rotation of the filler wire feeding roller 5 from time t1 to time t2. The tip of the filler wire WB is separated from the surface of the base material 6 by a predetermined distance by pulling up the filler wire WB at a predetermined feeding speed for a predetermined pulling-up time, that is, between times t2 and t3.
Assuming that the predetermined feeding speed is v1 and the predetermined lifting time is Δt, the distance d1 between the tip of the filler wire WB and the surface of the base material 6 is expressed as v1×Δt. The filler wire WB is kept at a predetermined distance from the base material 6 . This distance d1 is set to be greater than the height of the molten metal protruding from the periphery of the molten pool WP.

When the filler wire WB is pulled up for the predetermined pulling time, the filler wire feed control circuit FCT stops pulling up the filler wire WB.

At time t3, power supply unit 11 applies welding voltage V between welding wire WA and base material 6, and welding wire feed control circuit WCT starts feeding welding wire WA. It is preferable that the feeding speed of the welding wire WA at this time is slower than that during the regular welding of the main welding.

When the welding wire WA approaches the base material 6, the arc 9 is ignited at time t4 and the welding current I begins to flow. A molten pool WP begins to be formed in the base material 6 by the arc 9 . Also, the welding robot 10a moves the welding torch 2 and the liner 4 with respect to the base material 6 at a set welding speed at the timing when the arc 9 is ignited. The welding wire feed control circuit WCT increases the feeding speed of the welding wire WA to the speed during steady welding in the main welding.

At time t4, the filler wire WB has not yet reached the molten pool WP. As the welding torch 2 and the liner 4 advance, the molten pool WP reaches directly below the liner 4 at time t6. In buried arc welding, a large current of 300 A or more causes large penetration of the base material 6 and a deep molten pool WP is formed. The filler wire feed control circuit FCT causes the filler wire WB to enter the molten pool WP so that the filler wire WB starts entering the molten pool WP at the timing when the molten pool WP reaches directly below the liner 4 . Specifically, the filler wire feed control circuit FCT starts feeding the filler wire WB at time t5 before the molten pool WP reaches directly below the liner 4, and the filler wire WB reaches the base material 6. The feed timing and feed speed v(t) of the filler wire are controlled so that the timing coincides with the timing at which the molten pool WP reaches the feed destination of the filler wire WB.
Assuming that the distance between the welding torch 2 and the liner 4 is d0 and the welding speed is v0, the time at which the molten pool WP reaches directly below the liner 4 is expressed as follows.
t6=t4+d0/v0

The distance d1 between the filler wire WB and the base material 6 has already been recognized by preprocessing. Therefore, when the feed speed of the filler wire WB is v(t), the time t5 at which the feed of the filler wire WB is started and the feed speed v(t) of the filler wire WB are set so as to satisfy the following equation: You just have to decide. However, the integration in the following formula is the time integration from time t5 to t6.
d1=∫v(t)dt

In this manner, the filler wire feed control circuit FCT detects the contact between the filler wire WB and the base material 6 by measuring the feed load resistance of the filler wire WB with the feed load measurement circuit LD. By controlling the withdrawal and refeeding of the filler wire WB based on this time point, the filler wire WB can be supplied to the molten pool WP with good timing.

As described above, according to the welding apparatus and the arc welding method according to the present embodiment, the contact between the filler wire WB and the base material 6 is detected and the contact between the filler wire WB and the base material 6 is detected without preparing a power source other than the welding power source 1. It is possible to accurately control the feeding timing of the WB.

Further, according to the present embodiment, the contact between the filler wire WB and the base material 6 can be detected by a simple process of comparing the feeding load of the filler wire WB and the threshold value. Since the feed load of the filler wire WB is correlated with the current of the filler wire feed motor FM, the feed load can be measured from the current. A special additional circuit for measuring the feed load is not required, and contact between the filler wire WB and the base material 6 can be detected with a simple circuit configuration.

Furthermore, according to this embodiment, deep penetration is obtained by buried arc welding. Further, in buried arc welding, it is necessary to accurately control the supply of the filler wire WB to the molten pool WP, but according to this embodiment, the position of the tip of the filler wire WB can be accurately grasped. Therefore, the filler wire WB can enter the molten pool WP at the timing when the filler wire WB reaches the base material 6, and appropriate welding can be achieved.

In the present embodiment, the contact between the filler wire WB and the base material 6 is detected by comparing the feed load and the threshold value. The contact between the filler wire WB and the base material 6 may be detected based on the change mode.

Further, although the example in which the filler wire WB is fed after a predetermined time has passed since the arc 9 is ignited has been described, the configuration may be such that the filler wire WB is started to be fed at the same time as the arc 9 is ignited. . Further, although the example in which the feeding of the filler wire WB is started before the molten pool WP reaches directly below the liner 4 has been described, the feeding of the filler wire WB is started at the timing when the molten pool WP reaches directly below the liner 4. may be configured to start
If the filler wire WB can be supplied to the molten pool WP at the timing when the filler wire WB reaches the feed destination of the filler wire WB, the feed start timing and feed speed of the filler wire WB after the arc 9 is ignited are It is not particularly limited.

1: welding power source: welding torch, 3: welding wire feeding roller, 4: liner, 5: filler wire feeding roller, 6: base material, WA: welding wire, WB: filler wire, WP: molten pool, 11: Power supply unit 11a: power supply circuit 11b: control circuit FMD: filler wire feed control circuit LD: feed load measurement circuit

Claims (5)

2-wire for advancing the welding wire in the welding direction while forming a molten pool by generating an arc between the welding wire of the consumable electrode and the object to be welded, and supplying a filler wire to the molten pool from the rear of the welding direction. A method of initiating a weld, comprising:
feeding the filler wire toward the object to be welded;
measuring the feeding load of the filler wire;
determining whether or not there is contact between the filler wire and the object to be welded based on the measured feed load;
When it is determined that the filler wire has come into contact with the object to be welded, the filler wire is pulled back from the object to be welded by a predetermined amount;
After the ignition of the arc is started or after the welding wire and the filler wire start to advance in the welding direction, the filler wire is fed to the object to be welded at a timing and a feeding speed corresponding to the predetermined amount. How to start wire welding. The filler wire is fed to the object to be welded so that the timing at which the filler wire reaches the object to be welded matches the timing at which the molten pool reaches the feed destination of the filler wire. 2. The method for starting two-wire welding according to claim 1. 3. The method of starting two-wire welding according to claim 1 or 2, further comprising determining that the welding wire and the object to be welded have come into contact when the detected feed load is equal to or greater than a threshold. Welding under welding conditions in which the tip of the welding wire or the arc generation point in the liquid column formed at the tip enters the space surrounded by the recessed molten pool formed in the object to be welded by the arc. A method of starting a two-wire weld according to any one of claims 1 to 3. Welding equipment that advances the welding wire in the welding direction while forming a molten pool by generating an arc between the welding wire of the consumable electrode and the object to be welded, and supplies a filler wire to the molten pool from the rear of the welding direction. and
a filler wire feed control circuit for controlling feed of the filler wire;
a measuring circuit for measuring the feed load of the filler wire;
with
The filler wire feed control circuit includes:
determining whether or not there is contact between the filler wire and the object to be welded based on the feed load measured by the measurement circuit;
When it is determined that the filler wire has come into contact with the object to be welded, the filler wire is pulled back from the object to be welded by a predetermined amount;
After the ignition of the arc is started or after the welding wire and the filler wire start to advance in the welding direction, the filler wire is fed to the object to be welded at a timing and a feeding speed corresponding to the predetermined amount. Device.

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