JP2009285687A - Welding apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding apparatus and method in which equipment for welding is simplified and product quality is made stable, by eliminating restrictions in machining method, product structures and machining equipment structures. <P>SOLUTION: The welding apparatus includes a power source unit 1, a torch 2, an initial discharge absorbing member 3, and a holding part 5 for a workpiece W that is welded by a current discharged from the torch 2. The initial discharge absorbing member 3 is grounded and the workpiece W is directly or indirectly grounded via the holding part 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a welding apparatus and a welding method, and more particularly, to a welding apparatus and a welding method that can effectively prevent damage to electronic components and the like existing on a welding circuit.

Conventionally, welding is performed in order to perform processing such as joining of metals, and various techniques have been developed as techniques for performing this welding.
In arc welding, which is used as one of the welding methods, the base material and filler material (using the high heat generated by the arc generated between the base material and the electrode (melting rod, welding wire, TIG torch, etc.) ( Molten welding wires, melting rods, etc.) and process at the molecular and atomic level.

However, when performing such arc welding, a high voltage (several KV) is required at the start of generating the arc. If there are electronic parts on the welding circuit, these electric parts are electrically damaged. There was a case.
In this way, several techniques have been proposed in order to prevent electrical damage to electronic components and the like (see, for example, Patent Document 1).

Actual application No. 05-021576 (No. 06-019972) Full text and drawings

Patent Document 1 discloses a TIG welder.
In this technology, when a high frequency is superimposed on the output of the power supply when starting the welding arc, when the arc cannot be started, the high frequency is stopped for a certain period of time to prevent the provision of useless high frequency, and other electronic devices Can be reduced as much as possible.
As described above, in the present technology, when the arc is generated, the high frequency is stopped for a certain period of time, thereby preventing other electronic devices from being damaged.
Similarly, there is a method of limiting the power supply voltage. However, according to these techniques, workability is reduced because the processing conditions are restricted.

  In addition, as a method for preventing other electronic devices from being damaged when an arc is generated, a method of grounding an object to be welded has been proposed, but this is inconvenient because the product structure and processing equipment are limited. It is.

  The object of the present invention is to solve the above-mentioned problems and to simplify the apparatus for welding and stabilize the product quality by eliminating the limitations on the processing method and the product structure and the processing equipment structure. The present invention relates to a welding apparatus and a welding method capable of performing the above.

  According to the welding device of the present invention, the above-described problem is that a power supply device, a torch electrically connected to the power supply device, an initial discharge absorbing member installed in the vicinity of the torch, and discharge from the torch. Holding the workpiece to be welded by the electric current, the initial discharge absorbing member is grounded, and the workpiece is grounded directly or indirectly through the holding portion. Is solved.

  At this time, in the welding apparatus according to the present invention, it is preferable that at least one of the torch and the workpiece is configured to be movable in a direction in which they are separated from each other and close to each other.

  In addition, according to the welding method of the present invention, the above-described problem is the first in which the torch electrically connected to the power supply device and the initial discharge absorbing member installed in the vicinity of the torch are arranged close to each other. A second step of supplying current from the power supply device to the torch, a discharge between the torch and the initial discharge absorbing member, and a normal voltage from a high voltage state generated in the initial stage of discharge. A third step of waiting until the state is stabilized, and separating the torch and the initial discharge absorbing member while maintaining the discharge state at the time when the state is stabilized to the normal voltage state, and from the torch and the torch This is solved by performing the fourth step of bringing the torch and the workpiece to be brought close together by moving at least one of the workpieces to be welded by the discharged current.

As described above, in the present invention, welding is performed by a welding apparatus including a power supply device, a torch, an initial discharge absorbing member installed in the vicinity of the torch, and a holding portion for an object to be welded.
In this welding apparatus, the initial discharge absorbing member is grounded, and similarly, the workpiece is grounded directly or indirectly through the holding portion.
In addition, at least one of the torch and the workpiece is configured to be movable in a direction in which they are separated from each other and close to each other. First, a discharge is generated between the torch and the initial discharge absorbing member, and is generated at the initial stage of discharge. Wait until the high voltage state stabilizes from the high voltage state to the normal voltage state, and while maintaining the discharge state at the time when the normal voltage state is stabilized, the torch and the initial discharge absorbing member are separated from each other. Welding is performed by moving at least one of the torch and the workpiece to be brought close to each other.

Therefore, at the time of ignition in which a high voltage is instantaneously applied, discharge occurs between the torch and the initial discharge absorbing member.
Then, when the high voltage state is canceled and the normal voltage is in a steady state, at least one of the torch or the workpiece is moved, the discharge is transferred between the torch and the member to be welded, and welding is performed.
At this time, the torch may be moved in the direction of the workpiece, or the workpiece may be moved in the direction of the torch. Moreover, you may move both a torch and a to-be-welded member, and may adjoin both.
Since it is configured in this manner, electronic components and the like existing on the welding circuit are not damaged due to the high voltage at the time of ignition.
Moreover, the quality of the product formed by welding is also stabilized.
Furthermore, since the welding apparatus according to the present invention has a simple structure, the above effects can be easily obtained.

Further, at this time, in the welding apparatus according to the present invention, a shunt regulator is interposed between the workpiece and the initial discharge absorbing member, and the shunt regulator is electrically connected to the ground portion. It is preferable that they are connected.
Further, at this time, the shunt regulator flows through the workpiece by adjusting a resistance value between the workpiece and the ground portion and a resistance value between the initial discharge absorbing member and the ground portion. It is preferable that the current and the current flowing through the initial discharge absorbing member are adjusted.

  Further, in the welding method according to the present invention, a shunt regulator that is electrically connected to a ground portion is interposed between the workpiece and the initial discharge absorbing member, and the third step In the fourth embodiment, the shunt regulator adjusts a resistance value between the torch and the initial discharge absorbing member to be smaller than a resistance value between the torch and the workpiece, In the process, the shunt adjuster is configured to adjust a resistance value between the torch and the workpiece to be smaller than a resistance value between the torch and the initial discharge absorbing member. It is preferable that

When configured in this way, the resistance value between the workpiece and the ground part and the initial discharge absorbing member are separated by a shunt regulator interposed between the workpiece and the initial discharge absorbing member and connected to the ground. And the resistance value between the ground portion and the current flowing in the workpiece and the current flowing in the initial discharge absorbing member can be adjusted.
Therefore, the discharge from the torch to the initial discharge absorbing member and the discharge from the torch to the workpiece can be efficiently switched.
In other words, the shunt adjuster adjusts the resistance value between the torch and the initial discharge absorbing member to be smaller than the resistance value between the torch and the workpiece to be welded at the time of ignition. The resistance value between the weld and the weld is adjusted to be smaller than the resistance value between the torch and the initial discharge absorbing member.
As a result, at the time of ignition, discharge occurs between the torch and the initial discharge absorbing member, and at the time of welding, discharge occurs efficiently between the torch and the workpiece.

According to the present invention, at least one of the torch and the work piece is configured to be movable in a direction in which they are separated from each other and close to each other. First, a discharge is generated between the torch and the initial discharge absorbing member. While waiting for the high voltage state generated in the initial stage to stabilize to the normal voltage state, the torch and the initial discharge absorbing member are separated while maintaining the discharge state at the time when the normal voltage state is stabilized. By moving at least one of the workpieces, the torch and the workpiece can be brought close to each other and welding can be performed.
Further, the shunt regulator can efficiently switch between the discharge from the torch to the initial discharge absorbing member and the discharge from the torch to the workpiece.

  For this reason, it is possible to prevent electronic parts, etc. existing on the welding circuit from being damaged by high voltage at the time of ignition, and to eliminate limitations on processing methods and product structures and processing equipment structures. Can simplify the equipment and stabilize the product quality.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Note that the configuration described below does not limit the present invention and can be variously modified within the scope of the gist of the present invention.
The present embodiment relates to a welding apparatus and a welding method capable of simplifying an apparatus for welding and stabilizing product quality by eliminating restrictions on processing methods and product structures and processing equipment structures. .

  1 to 7 show an embodiment of the present invention. FIG. 1 is an explanatory view showing a welding apparatus, FIG. 2 is an explanatory view showing a welding apparatus during ignition energization and steady energization, and FIG. FIG. 4 is an explanatory diagram showing an arc ignition in the welding apparatus, FIG. 5 is an explanatory diagram showing an arc transition in the welding apparatus, and FIG. 6 is a welding process in the welding apparatus. FIG. 7 is an explanatory diagram showing the completion of welding in the welding apparatus.

FIG. 1 shows a welding apparatus S according to this embodiment.
The welding apparatus S which concerns on this embodiment has illustrated the TIG (Tungsten Inert Gas) welding apparatus. However, the present invention is not limited to this, and may be applied to any type of apparatus as long as it does not depart from the spirit of the present invention.
The welding apparatus S according to the present embodiment uses a torch 2 having a tungsten electrode, generates an arc A by discharge between the tungsten electrode and the workpiece W, and performs welding by heat from the arc A. It is a device for.
In the welding apparatus S, a shield is formed by an inert gas (for example, argon gas, helium gas, etc.) that is an inert gas, and welding is performed in the inert gas atmosphere.

The welding apparatus S mainly includes a power source 1 as a power source device, a torch 2, an ignition electrode 3 as an initial discharge absorbing member, a shunt regulator 4, and a holding unit 5.
The power source 1 according to the present embodiment is a normal power source and supplies power for generating the arc A.
The torch 2 according to the present embodiment is a tip instrument that is generally used when welding is performed.
The torch 2 is movable between the ignition electrode 3 and the workpiece W.
That is, the torch 2 itself is configured to be movable so that the free end side of the torch 2 is disposed at a position facing the ignition electrode 3 or the workpiece W.

In addition, a structure is not restricted to this, It may be comprised so that the to-be-welded object W may be moved, and the torch 2 which does not move may be moved, and both the torch 2 and the to-be-welded object W may be moved. , And may be configured to approach each other.
The ignition electrode 3 according to the present embodiment is an electrode for arc ignition, causes an arc discharge with the torch 2 at the time of ignition, and maintains that state until a steady state is reached.

The shunt regulator 4 according to this embodiment is a known current shunt regulator, and includes a shunt resistor 14 and a variable contact 15.
The shunt resistor 14 is a known resistor, and by adjusting the resistance value of the shunt resistor 14 by moving the variable contact 15, the amount of discharge (discharge direction) from the torch 2 to the ignition electrode 3 and the workpiece W to be welded. ).

The holding part 5 according to the present embodiment is a member for holding the workpiece W.
The workpiece W may be directly electrically connected to the flow dividing regulator 4 (in this case, the holding unit 5 simply holds the workpiece W), and the holding unit 5 is used for this purpose. May be electrically connected to the shunt regulator 4.

As shown in FIG. 1, a torch 2 and a shunt regulator 4 are connected to the power source 1, and the shunt regulator 4 is connected to a ground unit (not shown) of the power source 1 and is grounded.
Moreover, the electrode 3 for ignition and the to-be-welded object W are each electrically connected to the both ends of the shunt resistance 14 of the shunt regulator 4.
The current supplied from the power source 1 to the torch 2 is discharged toward the shunt regulator 4 having a voltage lower than that of the torch 2.
At this time, whether to discharge to the ignition electrode 3 or to the workpiece W is adjusted depending on the state of the shunt resistor 14 (that is, depending on the position of the variable contact 15).
That is, because the resistance value on the ignition electrode 3 side and the resistance value on the work piece W side change depending on the position of the variable contact 15 (proportional to the length of the resistance), discharge is performed toward the lower resistance value. .
Therefore, by adjusting the position of the variable contact 15, it is possible to control whether to discharge to the ignition electrode 3 or to the workpiece W.

Next, FIG. 2 shows an outline of the operating state of the welding apparatus S according to the present embodiment.
2A shows a state at the time of ignition, and FIG. 2B shows a state at the time of steady energization (that is, at the time of performing welding of the workpiece W).
As shown in FIG. 2A, at the time of ignition, the torch 2 is disposed at a position facing the ignition electrode 3, and the variable contact 15 of the shunt regulator 4 is connected to the ignition electrode 3 of the shunt resistor 14. (This position is referred to as “ignition position X”).
That is, it is connected to a position closest to the ignition electrode 3.

In this state, the distance between the ignition position X and the end portion of the shunt resistor 14 on the side of the ignition electrode 3 (hereinafter referred to as “the shunt resistor ignition electrode side R1”), the distance between the ignition position X and the shunt resistor 14 Comparing with the distance between the end of the weld W side (hereinafter referred to as “the shunt resistance welded object side R2”), the distance of the shunt resistance welded object side R2 is the distance of the shunt resistance ignition electrode side R1. Bigger than.
Therefore, the resistance value on the shunt resistance workpiece side R2 is much larger than the resistance value on the shunt resistance ignition electrode side R1.

In this embodiment, since the ignition position X is arranged so as to be substantially aligned with the connection portion of the ignition electrode 3, the electrical resistance of the shunt resistance ignition electrode side R1 is only about the line resistance caused by the connection. not exist.
Therefore, a large amount of current supplied from the power source 1 is discharged from the torch 2 to the ignition electrode 3 side, and hardly discharged to the work piece W side.
Therefore, when the power supply 1 is driven in this state, a circuit is constituted by the power supply 1, the ignition electrode 3, and the torch 2, and an arc A is generated between the torch 2 and the ignition electrode 3.

Further, when the ignition is finished and a steady state is reached and welding is performed, the torch 2 and the variable contact 15 are moved in the direction of the arrow (that is, the direction of the workpiece W).
FIG. 2B shows a state where the movement is completed.
Thus, at the time of welding, the torch 2 is disposed at a position facing the workpiece W, and the variable contact 15 of the shunt regulator 4 is connected to the workpiece W connection side of the shunt resistor 14 ( This position is referred to as “welding position Y”).
That is, it is connected to the position closest to the workpiece W.

In this state, when the distance on the shunt resistance ignition electrode side R1 is compared with the distance on the shunt resistance resistance workpiece side R2, the distance on the shunt resistance ignition electrode side R1 is greater than the distance on the shunt resistance resistance workpiece side R2. Also grows.
Therefore, the resistance value on the shunt resistance ignition electrode side R1 is much larger than the resistance value on the shunt resistance workpiece side R2.

In this embodiment, since the welding position Y is arranged so as to be substantially aligned with the workpiece W connection portion, the electrical resistance of the shunt resistance workpiece side R2 is only about the line resistance caused by the connection. not exist.
For this reason, a large amount of current supplied from the power source 1 is discharged from the torch 2 to the workpiece W side and hardly discharged to the ignition electrode 3 side.
Therefore, when the power source 1 is driven in this state, a circuit is constituted by the power source 1, the workpiece W, and the torch 2, and welding can be performed with the arc A generated between the torch 2 and the workpiece W. it can.

Thus, during arc ignition to which a high voltage is applied, the workpiece W and the welding circuit are not affected by the high voltage.
Therefore, it is possible to effectively eliminate damages to electronic components, product defects, and the like.
Further, after the steady state is reached, welding can be performed by the generated arc A by moving the torch 2 to a position facing the workpiece W.
In this state, as described above, since the voltage is in a steady state, there is no adverse effect on the electronic components and the workpiece W present in the welding circuit.

An example of a welding process using the welding apparatus S according to the present embodiment is shown in FIGS.
In the description of FIGS. 1 and 2, the example of moving the torch 2 has been described, but FIGS. 3 to 7 show examples of moving the workpiece W.
Similarly to the above, the configuration is not limited to this, and the torch 2 may be configured to move so as to approach the workpiece W that does not move, or both the torch 2 and the workpiece W may be moved. And may be configured to approach each other.

First, in step S1, ignition (that is, discharge) is performed to generate an arc A.
FIG. 4 illustrates this state as an explanatory diagram.
At the time of ignition, the torch 2 is disposed at a position facing the ignition electrode 3, and the variable contact 15 of the shunt regulator 4 is connected to the ignition electrode 3 connection side of the shunt resistor 14 (this position is referred to as “ Ignition position X ").
That is, it is connected to a position closest to the ignition electrode 3.

In this state, when the distance on the shunt resistance ignition electrode side R1 is compared with the distance on the shunt resistance welding object side R2, the distance on the shunt resistance welding object side R2 is greater than the distance on the shunt resistance ignition electrode side R1. Also grows.
Therefore, the resistance value on the shunt resistance workpiece side R2 is much larger than the resistance value on the shunt resistance ignition electrode side R1.

In this embodiment, since the ignition position X is arranged so as to be substantially aligned with the connection portion of the ignition electrode 3, the electrical resistance of the shunt resistance ignition electrode side R1 is only about the line resistance caused by the connection. not exist.
Therefore, a large amount of current supplied from the power source 1 is discharged from the torch 2 to the ignition electrode 3 side, and hardly discharged to the work piece W side.
Therefore, when the power supply 1 is driven in this state, a circuit is constituted by the power supply 1, the ignition electrode 3, and the torch 2, and an arc A is generated between the torch 2 and the ignition electrode 3.

Next, returning to FIG. 3, it is determined in step S2 whether or not the ignition has ended.
That is, it is determined whether or not the application of the high voltage generated instantaneously immediately after the discharge is finished.
This may be determined using a meter such as a voltmeter, or may be performed by analyzing a captured monitoring image or the like.
Moreover, you may be comprised so that it may advance to the next step using a timer.

If it is determined in step S2 that ignition has not ended (step S2: No), it is determined in step S3 whether a predetermined time has elapsed.
When it determines with predetermined time not having passed by step S3 (step S3: No), a process returns to step S2 and it is determined whether ignition was complete | finished.
If it is determined in step S3 that the predetermined time has elapsed (step S3: Yes), since there is a high possibility that some abnormality has occurred, error notification is performed in step S4, and the process ends.

This predetermined time is set to a time sufficient for the ignition to end.
Despite the elapse of the time set in this way, the ignition does not end (that is, the voltage is not stabilized at the normal voltage) means that some abnormality has occurred in the welding apparatus S or sensors. Since the possibility is high, an error is notified and the process is terminated.
Further, the error notification may be in any form such as notification by voice or notification that appeals to the eye, and is not necessarily performed if unnecessary.

If it is determined in step S2 that the ignition has been completed (step S2: Yes), the workpiece W and the variable contact 15 of the diversion regulator 4 are moved in step S5.
At this time, the workpiece W is moved in the direction of the torch 2 and the variable contact 15 is moved in the direction of the connection portion of the shunt resistor 14 with the workpiece W.
FIG. 5 shows this state as an explanatory diagram.

As shown in FIG. 5, the workpiece W is moved in the direction of the torch 2 after ignition.
At this time, the variable contact 15 is moved to the workpiece W connection side of the shunt resistor 14 in accordance with this operation.
That is, by changing the distribution of the resistance value on the shunt resistance ignition electrode side R1 and the resistance value on the shunt resistance work piece side R2, the current distribution is gradually changed, and the current distribution on the shunt resistance work piece side R2 side is changed. Decrease the resistance value and increase the current value.
By moving the workpiece W and the variable contact 15 in this manner, a circuit is gradually formed by the power source 1, the workpiece W and the torch 2, and the arc A is between the torch 2 and the workpiece W. Migrate to

Next, returning to FIG. 3, it is determined in step S6 whether the work piece W and the variable contact 15 have reached the predetermined positions.
That is, it is determined whether the workpiece W has reached the position adjacent to the torch 2 and whether the variable contact 15 has reached the welding position Y.
This may be determined by a sensor or the like, or may be configured to shift to the next step by a timer.

When it determines with the to-be-welded object W and the variable contact 15 not having reached to the predetermined position by step S6 (step S6: No), it is determined by step S7 whether predetermined time passed.
When it determines with predetermined time not having passed by step S7 (step S7: No), a process returns to step S6 and determines whether the to-be-welded object W and the variable contact 15 arrived at the predetermined position. .
If it is determined in step S7 that the predetermined time has elapsed (step S7: Yes), since there is a high possibility that some abnormality has occurred, error notification is performed in step S4, and the process is terminated.

The predetermined time is set to a time sufficient for the work piece W and the variable contact 15 to reach a predetermined position.
The fact that the workpiece W and the variable contact 15 do not reach the predetermined position in spite of the elapse of the set time means that some abnormality has occurred in the welding apparatus S or sensors. Therefore, the process is terminated after an error is notified.
Further, the error notification may be in any form such as notification by voice or notification that appeals to the eye, and is not necessarily performed if unnecessary.

When it determines with the to-be-welded object W and the variable contact 15 having reached | attained to the predetermined position by step S6 (step S6: Yes), welding is performed by step S8.
FIG. 6 shows an illustration of the state in which the workpiece W and the variable contact 15 have reached the predetermined position and are being welded.

In this state, the arc A is completely transferred between the torch 2 and the workpiece W.
That is, the circuit is completely constituted by the power source 1, the workpiece W and the torch 2, and normal welding is performed.
In this state, the workpiece W is melted and welding is performed.

Next, returning to FIG. 3, it is determined in step S9 whether or not welding has been completed.
This may be performed by processing and analyzing the captured image, or may be determined by a sensor or the like. Moreover, you may be comprised so that it may transfer to the next step with a timer.
When it determines with welding not being completed by step S9 (step S9: No), it is determined by step S10 whether predetermined time passed.

When it determines with predetermined time not having passed by step S10 (step S10: No), a process returns to step S9 and determines whether welding was completed.
If it is determined in step S10 that the predetermined time has elapsed (step S10: Yes), since there is a high possibility that some abnormality has occurred, error notification is performed in step S4, and the process ends.

This predetermined time is set to a time sufficient for completing the welding.
Even though the set time has elapsed, the fact that the welding is not completed means that there is a high possibility that some abnormality has occurred in the welding apparatus S or the like. It is supposed to end.
Further, the error notification may be in any form such as notification by voice or notification that appeals to the eye, and is not necessarily performed if unnecessary.

When it determines with welding having been completed by step S9 (step S9: Yes), a process is complete | finished.
FIG. 7 shows an explanatory diagram when welding is completed.
Thus, the workpiece W is welded, and the process is completed.

It is explanatory drawing which shows the welding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the welding apparatus at the time of ignition energization concerning one Embodiment of this invention, and regular energization. It is a flow which shows the welding process with the welding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the time of arc ignition with the welding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the time of the arc transfer with the welding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the time of welding with the welding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the time of the completion of welding with the welding apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

1. Power supply
2. Torch,
3. Ignition electrode,
4 ... Shunt regulator, 14 ... Shunt resistance, 15 ... Variable contact,
5. Holding part,
A ... Arc, R1 ... Shunt resistance ignition electrode side, R2 ... Shunt resistance workpiece side, S ... Welding device, W ... Workpiece

Claims (6)

A power supply;
A torch electrically connected to the power supply;
An initial discharge absorbing member installed in the vicinity of the torch;
A holding portion of a workpiece to be welded by a current discharged from the torch;
With
The initial discharge absorbing member is grounded, and the workpiece is grounded directly or indirectly through the holding portion.   The welding apparatus according to claim 1, wherein at least one of the torch and the workpiece is configured to be movable in a direction in which they are separated from each other and close to each other. A shunt regulator is interposed between the workpiece and the initial discharge absorbing member,
The welding apparatus according to claim 1, wherein the shunt regulator is electrically connected to a ground portion. The shunt regulator is
By adjusting a resistance value between the workpiece and the ground portion and a resistance value between the initial discharge absorbing member and the ground portion, a current flowing through the workpiece and a current flowing through the initial discharge absorbing member The welding apparatus according to claim 3, wherein the welding apparatus is configured to adjust the angle. A first step of arranging a torch electrically connected to the power supply device and an initial discharge absorbing member installed in proximity to the torch,
A second step of supplying current from the power supply to the torch;
A third step of causing discharge between the torch and the initial discharge absorbing member and waiting until the high voltage state generated in the initial stage of discharge is stabilized from the high voltage state to the normal voltage state;
The torch and the initial discharge absorbing member are separated from each other while maintaining a discharge state at a stable time to a normal voltage state, and at least one of the workpiece to be welded by the current discharged from the torch and the torch A fourth step of bringing the torch and the work piece close together by moving
Welding method characterized by performing. Between the workpiece and the initial discharge absorbing member, a shunt regulator that is electrically connected to the ground part is interposed,
In the third step, the shunt regulator adjusts the resistance value between the torch and the initial discharge absorbing member to be smaller than the resistance value between the torch and the work piece. ,
In the fourth step, the resistance value between the torch and the work piece is adjusted by the shunt regulator so as to be smaller than the resistance value between the torch and the initial discharge absorbing member. The welding method according to claim 5.

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