JP2005111495A - Arc welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an arc welding equipment wherein an electronic component with low voltage resistance mounted on the object to be welded is not damaged. <P>SOLUTION: Arc starting is performed between an electroconductive block 2 connected to either pole of a welding power source, and lying in a state of being electrically cut from a clamping fixture 6 clamping the part 13 to be welded in the object 1 to be welded and a torch 4 with an electrode connected to the other pole of the welding power source. After the arc starting, the electroconductive block 2 is moved by a cylinder 5 to electrically connect the electroconductive block 2 and the clamping fixture 6, and further, the torch 4 is moved to the part 13 to be welded in the object 1 to be welded clamped by the clamping fixture 6. Thus, the electrode and the part 13 to be welded are opposed to each other, and the welding of the part 13 to be welded is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an arc welding apparatus in which an electronic component having a low withstand voltage mounted on an object to be welded is not damaged.

Arc welding is a joining method in which an arc is generated between the electrode and the work piece, and the work piece is melt-bonded with the arc heat, and has a feature that the variation in joining quality is small compared to resistance welding or soldering. . In order to start an arc between the electrode and the workpiece, it is necessary to apply a high frequency voltage or a DC high voltage of several kV to several tens of kV between the electrode and the workpiece, and to generate them. The circuit is built into the welding power source.
When this arc welding is applied to the lead of an electronic component or a bus bar to which the electronic component is connected, it is connected to a welding power source so that the high frequency voltage or direct current high voltage will not enter the electrical circuit of the workpiece and be destroyed. The welded portions were securely grasped one by one with the conductive clamp jig thus formed, and the jointed portion and the single pole of the power source were connected.
In Patent Document 1, when connecting a lead terminal of a plurality of electronic components and a conductor having a connecting portion connected thereto, the connecting portion of the lead terminal and the conductor is aligned and welded.

JP 2002-134688 (pages 3 to 5, FIG. 1)

However, even when the welded parts are securely grasped one by one with the conductive clamping jig connected to the welding power source and the joint part is connected to one pole of the power source, depending on the circuit configuration, high frequency is generated by electromagnetic induction. There is a possibility that a voltage or a high DC voltage may enter an electric circuit, and arc welding cannot be applied to an electric circuit including an electronic component having a low withstand voltage. The same applies to Patent Document 1.
That is, there is a problem that a high-frequency voltage or a high direct-current voltage at the time of an arc starts to enter an electric circuit due to a problem of electromagnetic induction or clamping, and an electronic component having a low withstand voltage is destroyed.
In addition, there is a problem that if the contact process of the power supply electrode and the arc start are performed one by one because of fear of the electronic component destruction, the man-hours are increased and the productivity is very poor in the case of many parts to be welded.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an arc welding apparatus that does not damage an electronic component having a low withstand voltage mounted on an object to be welded.

  In the arc welding apparatus according to the present invention, an electrode connected to one electrode of the welding power source, a first conductive block connected to the other electrode of the welding power source and performing arc activation with the electrode, and the conductivity Clamping means formed of a material and holding the welded part of the workpiece to be welded, and starting the arc on the surface of the first conductive block with the first conductive block and the clamp means being electrically disconnected. In addition, after the arc is started, the first conductive block and the clamping means are electrically connected, the electrode is moved to face the welded portion, and the welded portion is welded.

  As described above, the present invention provides an electrode connected to one electrode of a welding power source, a first conductive block connected to the other electrode of the welding power source and performing arc activation with the electrode, and a conductive property. Clamping means formed of a material and holding the welded part of the work piece, and starting the arc on the surface of the first conductive block in a state where the first conductive block and the clamping means are electrically cut. In addition, after the arc is started, the first conductive block and the clamping means are electrically connected, the electrode is moved to oppose the welded part, and the welded part is welded. By performing the electrical disconnection, it is possible to prevent damage to an electronic component with a low withstand voltage mounted on the workpiece.

Embodiment 1 FIG.
1 is an overall configuration diagram showing an arc welding apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a conductive block 2 (first conductive block) that is electrically disconnected from the workpiece 1 is disposed, and the conductive block 2 is electrically connected to one electrode of a welding power source 3. On the conductive block 2, a torch 4 having an electrode connected to one electrode (opposite electrode of the conductive block 2) of the welding power source 3 is arranged, and arc starting is performed. The conductive block 2 is moved by a cylinder 5 or the like, and a welded portion clamped by a clamp jig 6 (clamp means) is disposed at the movable tip. The clamp jig 6 is moved by a cylinder 7 or the like. The torch 4 is moved by the robot 8. Further, a gable 10 for supplying power and gas from the welding power source 3 and the gas supply source 9 to the torch 4 is provided. The cylinders 5 and 7, the clamp jig 6 and the robot 8 are fixed on the base 11. The robot 8, the welding power source 3, and the cylinders 5 and 7 are controlled by the control device 12.

FIG. 2 is a diagram showing arc activation of the arc welding apparatus according to Embodiment 1 of the present invention.
2, 1, 2, 4 to 6 are the same as those in FIG. A welding location 13 of the workpiece 1 is held by the clamp jig 6. An electrode 14 is provided on the torch 4. The welded portion 13 is a bus bar that includes an electronic component lead or an electronic component and constitutes an electrical circuit.

FIG. 3 is a diagram showing an electrical connection between the welded portion and the conductive block of the arc welding apparatus according to Embodiment 1 of the present invention.
In FIG. 3, 1, 2, 4-6, 13, and 14 are the same as those in FIG.
FIG. 4 is a diagram showing welding of an object to be welded by the arc welding apparatus according to Embodiment 1 of the present invention.
In FIG. 4, 1, 2, 4-6, 13, and 14 are the same as those in FIG.
FIG. 5 is a diagram showing the relationship between the clamp jig and the welded portion of the arc welding apparatus according to Embodiment 1 of the present invention.
5, 1, 4, 6, and 13 are the same as those in FIG.

Next, the operation will be described.
First, the torch 4 is disposed on the conductive block 2 and arc starting is performed. The conductive block 2 is moved by a cylinder 5 or the like, and a welded spot 13 clamped by a clamp jig 6 is disposed at the movable tip. The clamp jig 6 is configured to hold the material to be welded immediately below the welded part 13, and the material of the clamp jig 6 is made of a conductive material.

Next, as shown in FIG. 3, after confirming the arc start, the conductive block 2 is moved, and the conductive block 2 and the clamp jig 6 at the welded portion 13 are brought into contact with each other to electrically connect them. . The movement of the conductive block 2 may be performed under the control of the control device 12 or may be performed manually. In addition, instead of electrical connection by contact between the conductive block 2 and the clamp jig 6, one electrode of the welding power source 3 to which the conductive block 2 is connected and the clamp jig 6 may be directly connected by a cable or the like. Good. However, the electrical connection between the clamp jig 6 and the welding power source 3 is performed after the arc is started, and both are electrically disconnected before the arc is started.
Next, as shown in FIG. 4, while the arc is formed, the torch 4 is moved from the conductive block 2 to a position immediately above the welded portion 13 sandwiched between the clamp jigs 6, and TIG welding is performed. The movement of the torch 4 may be performed after the movement of the conductive block 2 is completed, or may be performed in parallel with the movement of the conductive block 2.
In addition, the confirmation of arc starting is performed by monitoring the current value flowing through the conductive block 2 by installing an ammeter in an electric circuit inside the welding power source or a cable connected to the output terminal of the welding power source, It may be performed by confirming by the control device 12 that the current value has reached a desired value, or by visually recognizing an arc.

When welding is performed in such a procedure, the arc is started at a distance from the work piece 1, so that high-frequency voltage and DC high voltage at the start of the arc are prevented from flowing into the electric circuit of the work piece 1 by electromagnetic induction. The electronic component with a low withstand voltage mounted on the workpiece 1 is not damaged.
In addition, since the start of the arc can be confirmed by monitoring the value of the current flowing through the conductive block 2, the conductive block 2 can be moved with a minimum time lag from the start of the arc, and the cycle time of the apparatus can be shortened to increase the productivity. improves.
Furthermore, as shown in FIG. 5, by covering the portion other than the welded portion 13 with the clamp jig 6, it is possible to prevent the arc light from hitting the workpiece 1 and to prevent the workpiece 1 from being damaged by the radiant heat. At the same time, damage to equipment can be prevented.

Here, by forming the clamp jig 6 from a high-strength copper alloy having high thermal conductivity, the temperature rise of the clamp jig 6 can be suppressed, damage can be suppressed, and the life thereof can be improved.
In addition, by cooling the clamp jig 6 with water, the temperature rise of the clamp jig 6 can be suppressed, damage can be suppressed, and the life thereof can be improved.

Further, by forming the arc starting conductive block 2 from pure copper or copper alloy having high thermal conductivity, the temperature rise of the conductive block 2 can be suppressed, damage can be suppressed, and the life thereof can be improved.
Furthermore, by cooling the arc starting conductive block 2 with water, the temperature rise of the conductive block 2 can be suppressed, damage can be suppressed, and the life thereof can be improved.

Further, by setting the distance between the conductive block 2 for starting the arc and the electrode of the welding torch 4 to 1 mm or less, the arc is surely started, so that the apparatus can be prevented from being stopped due to the arc not starting.
Moreover, by making the setting current at the time of arc starting lower than the setting current at the time of welding, the temperature rise of the conductive block 2 can be suppressed, damage can be suppressed, and the lifetime is improved.
Furthermore, by changing the positional relationship between the conductive block 2 and the welding torch 4 at the time of starting the arc every arbitrary number of times of starting the arc, the surface of the conductive block 2 is always in a state where the arc can be easily started. Stop can be prevented.
Further, by detecting a decrease in the welding current and setting the arc voltage to zero by the control device 12, it is possible to prevent damage to components having a low withstand voltage due to no-load voltage.

In addition, by using a welding power source that starts an arc with a DC high voltage, the influence of electromagnetic induction can be reduced, the distance between the conductive block 2 and the workpiece 1 can be reduced, and the apparatus is compact. At the same time, cycle time can be shortened and productivity can be improved.
Moreover, by using a TIG welding power source or a plasma welding power source, spatter does not occur, and a short circuit failure of an object to be welded can be prevented.

According to the first embodiment, the arc is activated by the conductive block in a state of being electrically disconnected from the workpiece, and the high frequency voltage and DC high voltage at the time of arc activation are not directly applied to the welded portion. Does not damage electronic components with low withstand voltage mounted on objects.
Further, since the arc activation can be confirmed by monitoring the value of the current flowing through the conductive block, the conductive block can be moved with a minimum time lag from the arc activation, and the cycle time of the apparatus can be shortened, thereby improving the productivity.
Further, by covering the parts other than the welded portion with the clamp jig, it is possible to prevent the arc light from hitting the work piece, and to prevent the work piece from being damaged by the radiant heat, and at the same time, the equipment can be prevented from being damaged.

Embodiment 2. FIG.
FIG. 6 is a view showing a clamp jig of an arc welding apparatus according to Embodiment 2 of the present invention.
In FIG. 6, reference numerals 1, 6, and 13 are the same as those in FIG.
FIG. 7 is a view showing a comb-shaped clamping jig of an arc welding apparatus according to Embodiment 2 of the present invention.
In FIG. 7, 6 and 13 are the same as those in FIG.

In the second embodiment, as shown in FIG. 6, when there are a plurality of welded portions 13 described in the first embodiment, the welded portions 13 have the same shape and are provided with a clamping jig 6 that can be collectively clamped.
Thereby, since it can weld on the same conditions, without starting arc one by one, productivity improves.

In addition, as shown in FIG. 7, since the clamp jig 6 is formed in a comb-tooth shape, the arc is not interrupted when the torch moves through the welded portion 13, so that the withstand voltage with a load of high frequency voltage or DC high voltage No arc restarts that could damage low electronic components.
Further, by setting the distance between the clamp jig 6 and the electrode of the welding torch 4 to be 5 mm or less, the arc is not interrupted when the torch 4 moves through the welded portion 13 even if the clamp jig 6 is not comb-shaped. Therefore, arc restart that may damage an electronic component having a low withstand voltage with a high-frequency voltage or a high DC voltage load does not occur.

According to the second embodiment, when there are a plurality of parts to be welded having the same shape, it can be clamped collectively, and welding can be performed under the same conditions without starting the arc one by one, so that productivity is improved.
In addition, since the arc does not break when the torch moves through the welded part, it is possible to prevent arc restart that may damage electronic components with low withstand voltage due to high-frequency voltage or DC high-voltage load. it can.

Embodiment 3 FIG.
FIG. 8 is a diagram showing a gas nozzle of an arc welding apparatus according to Embodiment 3 of the present invention.
In FIG. 8, 1, 6, 13, and 14 are the same as those in FIG.

  The third embodiment relates to the supply of shield gas that covers the welded part 13. Normally, the shielding gas is supplied from the torch 4, but in the third embodiment, when the plurality of welded portions 13 described in the second embodiment are clamped collectively, as shown in FIG. The shield gas supplied from 15 covers a plurality of welded locations 13 at the same time, and the gas nozzle 15 is fixed, and only the electrode 14 moves to weld the welded locations 13 sequentially.

  According to the third embodiment, since the gas nozzle does not move following the electrode, a shield atmosphere at the welded portion is stably formed, and surface oxidation and blowholes in the welded portion are not generated.

Embodiment 4 FIG.
FIG. 9 is a diagram showing a conductive block for connecting a plurality of clamp jigs of an arc welding apparatus according to Embodiment 4 of the present invention.
9, reference numerals 1, 6, and 13 are the same as those in FIG. In FIG. 9, there are a plurality of clamp jigs 6, the clamp jigs 6 are connected by the conductive block 16, and the conductive block 16 is moved by the cylinder 17 or the like.

The fourth embodiment is a case where there are a plurality of clamping jigs 6 of the first embodiment. A conductive block 16 (second conductive block) connecting between the clamping jigs 6 is inserted and arranged by a cylinder 17 or the like. .
As a result, even when the parts to be welded 13 are separated from each other and the clamping directions are different, welding can be performed without starting an arc for each clamp portion, and thus productivity is improved.

Here, by forming the conductive block 16 from pure copper or copper alloy having a high thermal conductivity, the temperature rise of the conductive block 16 can be suppressed, damage can be suppressed, and the life thereof can be improved.
In addition, by cooling the conductive block 16 with water, the temperature rise of the conductive block 16 can be suppressed, damage can be suppressed, and the life thereof is improved.

  According to the fourth embodiment, since the welding can be performed without starting the arc for each clamp portion even when the parts to be welded are separated or when the clamp directions are different, productivity is improved.

Embodiment 5 FIG.
FIG. 10 is a diagram showing an airtight chamber of an arc welding apparatus according to Embodiment 5 of the present invention.
10, 1, 4, 6, 13, and 14 are the same as those in FIG. The hermetic chamber 18 is filled with an inert gas such as Ar gas.

In the fifth embodiment, as shown in FIG. 10, the electrode 14 and the welded portion 13 are placed in an airtight chamber 18 filled with an inert gas such as Ar gas and welded.
Thereby, the shield atmosphere of the to-be-welded location 13 is formed stably, and the surface oxidation and blowhole of a welding part do not generate | occur | produce.

  According to the fifth embodiment, the shield atmosphere of the welded portion is stably formed, and welding that does not generate surface oxidation or blowholes in the welded portion can be performed.

Embodiment 6 FIG.
FIG. 11 is a diagram showing a moving conductive sheet of an arc welding apparatus according to Embodiment 6 of the present invention.
11, 2, 4, 5, and 14 are the same as those in FIG. In FIG. 11, the conductive sheet 19 is arranged so as to move on the conductive block 2 so as to face the electrode 14. The conductive sheet 19 is moved by the sheet feeding mechanism 20, and an arc is formed at a position facing the electrode 14. Enable the starting location 21. The conductive sheet 19 is cleaned by a rotating brush 22 (cleaning means).

  In the sixth embodiment, as shown in FIG. 11, a conductive sheet 19 that is in close contact with the surface of the conductive block 2 is disposed, and the conductive sheet 19 is moved every arbitrary number of arc activations to have different surface positions ( The arc is started at the arc starting point 21).

  Here, since the surface of the conductive sheet 19 is mechanically cleaned by brushing or the like, the arc can be started again on the surface of the sheet once the arc is started, so that the life of the conductive sheet is improved.

  According to the sixth embodiment, as a result, the conductive sheet is always in a state in which an arc is likely to be activated, and since the arc is reliably activated, it is possible to prevent the apparatus from being stopped due to the arc not being activated.

Embodiment 7 FIG.
FIG. 12 is a diagram showing a space surrounding an electrode and a welded portion of an arc welding apparatus according to Embodiment 7 of the present invention.
In FIG. 12, 1, 2, 4-6, 13, and 14 are the same as those in FIG. The enclosure 23 forms a space.

In the seventh embodiment, as shown in FIG. 12, the electrode 14 is arranged from the upper surface and the welded portion 13 is arranged from the bottom surface where the hole is opened in the enclosure 23 in which the side surface and the bottom surface form an enclosed space. The entire range is defined as a space surrounded by one enclosure 23.
By welding in the enclosure 23, the radiant heat of the arc light can be shielded by shielding the enclosure 23, so that thermal damage other than the welded portion 13 of the workpiece 1 can be prevented, and equipment damage due to heat can also be prevented.

  Here, if an inert gas heavier than air, such as Ar, is supplied to the space surrounded by the enclosure 23 and welding is performed, the shield atmosphere of the welded portion 13 is stably formed, and surface oxidation and blow of the welded portion are performed. No holes are generated.

  According to the seventh embodiment, since the radiant heat of the arc light can be enclosed and shielded, it is possible to prevent thermal damage other than the welded portion of the work piece and also prevent damage to the equipment due to heat, and shield the welded portion. The atmosphere can be stably formed, and surface oxidation and blowholes at the welded portion can be prevented from occurring.

1 is an overall configuration diagram showing an arc welding apparatus according to Embodiment 1 of the present invention. It is a figure which shows the arc starting of the arc welding apparatus by Embodiment 1 of this invention. It is a figure which shows the electrical connection of the to-be-welded part and electroconductive block of the arc welding apparatus by Embodiment 1 of this invention. It is a figure which shows welding of the to-be-welded object of the arc welding apparatus by Embodiment 1 of this invention. It is a figure which shows the relationship between the clamp jig | tool of the arc welding apparatus by Embodiment 1 of this invention, and a to-be-welded part. It is a figure which shows the clamp jig | tool of the arc welding apparatus by Embodiment 2 of this invention. It is a figure which shows the comb-shaped clamp jig | tool of the arc welding apparatus by Embodiment 2 of this invention. It is a figure which shows the gas nozzle of the arc welding apparatus by Embodiment 3 of this invention. It is a figure which shows the electroconductive block which connects between several clamp jig | tools of the arc welding apparatus by Embodiment 4 of this invention. It is a figure which shows the airtight chamber of the arc welding apparatus by Embodiment 5 of this invention. It is a figure which shows the electroconductive sheet which the arc welding apparatus by Embodiment 6 of this invention moves. It is a figure which shows the space which surrounds the electrode of the arc welding apparatus by Embodiment 7 of this invention, and a to-be-welded part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Workpiece 2 Conductive block 3 Welding power source 4 Torch 5 Cylinder 6 Clamp jig 7 Cylinder 8 Robot 9 Gas supply source 10 Cable 11 Base 12 Controller 13 Welded place 14 Electrode 15 Gas nozzle 16 Conductive block 17 Cylinder 18 Airtight Chamber 19 Sheet 20 Sheet feeding mechanism 21 Arc starting point 22 Rotating brush 23 Enclosure

Claims (27)

  An electrode connected to one electrode of the welding power source, a first conductive block connected to the other electrode of the welding power source and arc-actuated with the electrode, and a conductive material, and an object to be welded Clamping means for holding the welded portion of the first conductive block, and starting the arc on the surface of the first conductive block in a state where the first conductive block and the clamping means are electrically disconnected, and the arc Arc welding characterized in that after starting, the first conductive block and the clamp means are electrically connected, the electrode is moved to oppose the welded part, and the welded part is welded. apparatus.   An electrode connected to one electrode of the welding power source, a first conductive block connected to the other electrode of the welding power source and arc-actuated with the electrode, and a conductive material, and an object to be welded Clamping means for holding the welded portion of the welding power source, and starting the arc on the surface of the first conductive block in a state where the other pole of the welding power source and the clamping means are electrically disconnected. An arc welding apparatus characterized in that the other electrode of the welding power source and the clamping means are electrically connected later, the electrode is moved to oppose the welded part, and the welded part is welded.   The arc welding apparatus according to claim 1 or 2, wherein the first conductive block and the electrode change a relative position at the time of arc starting every arbitrary number of times of arc starting.   The arc welding apparatus according to any one of claims 1 to 3, wherein the arc is started by setting a distance between the first conductive block and the electrode to 1 mm or less.   An electrode connected to one electrode of the welding power source, a first conductive block connected to the other electrode of the welding power source, and a close contact with the surface of the first conductive block. A conductive sheet that is coupled to the electrode and is moved over the first conductive block such that an arc is initiated between the electrode and the arc is activated at a different surface for any number of arc starts, And a clamp means that is formed of a conductive material and holds a welded portion of the work piece, and the first conductive block and the clamp means are electrically disconnected from each other on the surface of the conductive sheet. Arc start is performed, and after the arc start, the first conductive block and the clamping means are electrically connected, the electrode is moved to oppose the welded part, and welding of the welded part is performed. line Arc welding apparatus characterized by.   An electrode connected to one electrode of the welding power source, a first conductive block connected to the other electrode of the welding power source, and a close contact with the surface of the first conductive block. A conductive sheet that is coupled to the electrode and is moved over the first conductive block such that an arc is initiated between the electrode and the arc is activated at a different surface for any number of arc starts, And a clamp means that is formed of a conductive material and holds the welded portion of the work piece, and arcs on the surface of the conductive sheet in a state where the other electrode of the welding power source and the clamp means are electrically disconnected. And starting the arc, electrically connecting the other electrode of the welding power source and the clamping means after starting the arc, moving the electrode to oppose the welded part, and welding the welded part. Features Arc welding apparatus.   The arc welding apparatus according to claim 5 or 6, further comprising a cleaning means for mechanically cleaning the surface of the conductive sheet.   The arc welding apparatus according to any one of claims 1 to 7, wherein the clamp means collectively holds a plurality of welding locations.   9. The arc welding apparatus according to claim 8, wherein the clamping means has a comb-tooth shape so as to sandwich the plurality of welded portions.   The arc welding apparatus according to claim 8 or 9, wherein a distance between the clamp means and the electrode is 5 mm or less.   The arc welding according to any one of claims 1 to 10, wherein a plurality of the clamp means are provided, and a second conductive block is provided so as to connect the clamp means. apparatus.   The arc welding apparatus according to claim 11, wherein the second conductive block is formed of a copper alloy.   The arc welding apparatus according to claim 11 or 12, wherein the second conductive block is water-cooled.   The arc welding apparatus according to any one of claims 8 to 10, further comprising a gas nozzle that is arranged at a fixed position and supplies a shielding gas so as to cover the plurality of welded portions.   14. An airtight chamber filled with an inert gas, the electrode and the welded portion are accommodated in the inert gas in the airtight chamber, and welding is performed. An arc welding apparatus according to claim 1.   The arc welding apparatus according to any one of claims 1 to 15, wherein the clamping means is configured to block arc light from an object to be welded.   An enclosure having a bottom surface provided with a side surface and a hole is provided, the electrode is arranged from the upper part of the enclosure, the welded portion is arranged from the hole in the bottom surface, and welding is performed in the enclosure. The arc welding apparatus according to any one of claims 1 to 13.   The arc welding apparatus according to claim 17, wherein an inert gas having a specific gravity greater than that of air is supplied to the enclosure.   The arc welding apparatus according to any one of claims 1 to 18, wherein the clamping means is made of a copper alloy.   The arc welding apparatus according to any one of claims 1 to 19, wherein the clamp means is water-cooled.   The arc welding apparatus according to any one of claims 1 to 20, wherein the first conductive block is made of pure copper or a copper alloy.   The arc welding apparatus according to any one of claims 1 to 21, wherein the first conductive block is water-cooled.   A monitoring means for monitoring a current flowing through the first conductive block is provided, and the arc starting is confirmed when a current value monitored by the monitoring means exceeds a predetermined value. The arc welding apparatus according to claim 22.   The arc welding apparatus according to any one of claims 1 to 23, wherein a set current at the time of starting the arc is lower than a set current at the time of welding.   The arc welding apparatus according to any one of claims 1 to 24, further comprising a control device that detects a decrease in welding current and sets an arc voltage to zero.   The arc welding apparatus according to any one of claims 1 to 25, wherein the welding power source supplies a DC high voltage.   The arc welding apparatus according to any one of claims 1 to 25, wherein the welding power source is a TIG welding power source or a plasma welding power source.

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