JPH0740045A - Filler wire supply tig welding equipment - Google Patents

Abstract

PURPOSE:To provide the filler wire supply TIG welding equipment capable of arranging a tungsten electrode and a filler wire close to each other and obtaining the satisfactory welding quality. CONSTITUTION:In the filler wire supply TIG welding equipment provided with a power source part 1 which supplies a TIG arc current to the tungsten electrode 6, a wire feed part 9 which supplies the filler wire 8 to a weld zone and control parts 10 and 11 which control these power source part and wire feed part, a contact detection circuit 20 which detects whether or not the filler wire tip is brought into contact with base metal 5 is provided. When the filler wire is brought into contact with the base metal right before an arc is started, the power source part is controlled so that the arc start is stopped by the control part. When the filler wire 8 is brought into contact with the base metal 5 right before the arc is started, the wire feed part 9 is driven reversely to separate the filler wire from the base metal and then, the power source part 1 and the wire feed part 9 can be controlled so that the arc is started.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a filler wire supply TIG.
The present invention relates to a welding device, and more particularly, to a configuration of a control unit that controls starting and stopping of a power supply unit and a filler wire feeding unit.

[0002]

2. Description of the Related Art FIG. 6 shows a configuration example of a conventionally known filler wire supply TIG welding apparatus. As is clear from this figure, the welding apparatus of the present example is provided with a power supply unit 1 for supplying a TIG arc current, an arc power cable 2 and a welding ground cable 3 connected to the output end of the power supply unit 1, and an arc power cable. TIG torch 4 connected to 2,
The base material 5 which is the object to be welded connected to the welding earth cable 3 and the tungsten electrode 6 held by the TIG torch 4.
A filler wire 8 supplied to the welded portion (the arc 7 generation portion), a filler wire feeder 9 for feeding the filler wire 8, and a wire feed controller 10 for controlling the feed amount of the filler wire 8 by the feeder 9. And a welding control unit 11 that controls the start / stop timing of the power supply unit 1 and the TIG arc current amount, and the start / stop timing of the wire feed control unit 10 and the feed amount of the filler wire 8.

In the welding apparatus of this example, at the time of starting an arc, a high voltage is applied between the base material 5 and the tungsten electrode 6 to cause a spark discharge between them and generate an arc 7 induced thereby. Let's do the welding. At this time, the power supply unit 1
The TIG arc current supplied from the welding ground cable 3, base material 5, arc 7, tungsten electrode 6, TIG
It flows through the path of the torch 4 and the arc power cable 2.

In the welding apparatus having such a structure, if the base material 5 is in contact with the filler wire 8 immediately before the start of the arc, the base material 5 and the filler wire 8 have the same potential, so that the base material 5 and the tungsten electrode. The spark discharge due to the high voltage applied between the tungsten electrode 6 and the base material 5
Or between the tungsten electrode 6 and the filler wire 8, whichever is closer.

In a conventional filler wire supply TIG welding apparatus, the distance from the tungsten electrode 6 to the filler wire 8 is set to be larger than the distance from the tungsten electrode 6 to the base material 5. Even if the filler wire 8 is in contact with 5, the spark discharge and the subsequent arc are generated between the tungsten electrode 6 and the base material 5, and do not occur between the tungsten electrode 6 and the filler wire 8.

[0006]

However, in this type of welding apparatus mounted on a robot or the like, the TIG torch 4 and the filler wire 8 are brought close to each other in order to downsize the TIG torch 4 and the wire feeding portion 9. Needed, Figure 7
There is also proposed an integrated TIG torch in which the filler wire 8 is placed in the TIG torch 4 and the tungsten electrode 6 and the filler wire 8 are brought close to each other as shown in FIG. In the welding device having such an integrated TIG torch, since the distance from the tungsten electrode 6 to the filler wire 8 is smaller than the distance from the tungsten electrode 6 to the base material 5, the filler wire 8 is in contact with the base material 5. When the arc start switch provided in the welding control unit 11 is switched to start the arc, a spark discharge and an arc are generated between the tungsten electrode 6 and the filler wire 8. as a result,
The filler wire 8 is abruptly heated, and the melted and blown filler wire 8 is finely divided and scattered around, so that the base material 5 and the tungsten electrode 6 tend to adhere to each other. If the scattered filler wire 8 adheres to the vicinity of the tip of the tungsten electrode 6, it adversely affects the behavior of the arc and causes deterioration of the quality of the welded portion. In addition, the integrated T
The same inconvenience occurs in a welding device having a small distance from the tungsten electrode 6 to the filler wire 8 other than the welding device having an IG torch.

The present invention has been made to solve the above technical problems, and an object thereof is to allow a tungsten electrode and a filler wire to be arranged close to each other.
Another object of the present invention is to provide a filler wire supply TIG welding device that can obtain good welding quality.

[0008]

In order to achieve the above-mentioned object, the present invention firstly provides a power supply section for supplying a TIG arc current, and a filler wire feeding section for feeding a filler wire,
In a filler wire supply TIG welding apparatus provided with a control unit for controlling these power supply unit and filler wire feeding unit,
A contact detection circuit for detecting whether or not the filler wire is in contact with the base material is provided, and when the filler wire is in contact with the base material immediately before the arc start, the control unit stops the arc start. It is configured to control the power supply unit.

Secondly, in the same filler wire supply TIG welding apparatus as described above, a contact detection circuit for detecting whether or not the filler wire is in contact with the base material is provided, and the filler wire is contacted with the base material immediately before the arc start. During this, the filler wire feeder is reversely driven to separate the filler wire from the base material, and then the power supply unit and the filler wire feeder are controlled so as to start an arc.

[0010]

[Operation] Whether or not the filler wire is in contact with the base material
It can be detected by measuring the potential difference between the filler wire and the base material.If the filler wire and the base material are at the same potential, it can be determined that they are in contact, and if they are not at the same potential, they are not in contact. It can be determined that it is in a state. Further, the start / stop of the power supply unit and the filler wire feeding unit, the feeding direction of the filler wire, and the like can be performed by switching the control program of the control unit according to a signal from the contact detection circuit.

When it is determined that the filler wire is in contact with the base metal immediately before the arc start, the control unit controls the power supply unit to stop the arc start, and spark discharge occurs between the tungsten electrode and the filler wire. Since it is possible to prevent the occurrence of inconvenience, it is possible to prevent the occurrence of inconvenience caused by the melting and scattering of the filler wire. In the same case, first, the filler wire feeding unit is reversely driven to separate the filler wire from the base metal, and then the power supply unit and the filler wire feeding unit are activated to start an arc, so that the distance from the tungsten electrode to the filler wire is increased. Since the distance from the tungsten electrode to the base material is smaller than that, a spark discharge and an arc can be correctly generated between the tungsten electrode and the base material.
Scattering is prevented and a good weld can be obtained. Further, in this case, the welding work can be continued regardless of whether or not the filler wire is in contact with the base material, so that the workability can be prevented from being deteriorated.

[0012]

EXAMPLE A filler wire supply TIG welding apparatus according to a first example will be described with reference to FIGS. FIG. 1 is a block diagram of a welding apparatus according to this example, FIG. 2 is a block diagram of a contact detection circuit, and FIGS. 3 and 4 are operation explanatory diagrams of the welding apparatus according to this example.

In FIG. 1, reference numeral 20 denotes a contact detection circuit, and the other parts corresponding to those of the device shown in FIGS. 6 and 7 have the same reference numerals. That is, in the filler wire supply TIG welding apparatus of this example, the contact detection circuit 20 is attached to the welding apparatus shown in FIGS. 6 and 7, and the arc start is controlled according to the presence or absence of the contact state between the base material and the filler wire. It is characterized by doing so.
Therefore, regarding the parts other than the contact detection circuit 20,
Description is omitted to avoid duplication.

The contact detection circuit 20 detects the potential between the base material 5 and the filler wire 8, that is, the wire terminal voltage Vw. When Vw has the same potential, that is, the base material 5 is in contact with the filler wire 8. In this case, the contact signal “L” is input to the welding control unit 11, and when Vw is not the same potential, that is, when the filler wire 8 is separated from the base material 5, the non-contact signal “H” is input to the welding control unit 11. input.

FIG. 2 shows an example of the contact detection circuit 20.
The contact detection circuit 20 of this example has a pulse-shaped TIG on the base material 5.
It is suitable for welding equipment that applies arc current,
It is composed of a sample hold circuit (S / H) 21, a zero-cross signal forming circuit 22, a reference voltage setting circuit 23, and a comparison circuit 24.

The sample hold circuit 21 inputs the wire terminal voltage Vw and the zero cross signal of the commercial power supply voltage from the zero cross signal forming circuit 22 and samples and holds the wire terminal voltage Vw during the non-conduction period of the TIG arc current. The output voltage value (V
w) has the same potential as the base material 5 when the filler wire 8 is in contact with the base material 5, and does not have the same potential as the base material 5 when the filler wire 8 is separated from the base material 5. In the reference voltage setting circuit 23, a reference voltage Vr that is equal to or higher than the output voltage value when the filler wire 8 is in contact with the base material 5 and is equal to or lower than the output voltage value when the filler wire 8 is separated from the base material 5 is set. ing. The comparison circuit 24 compares the reference voltage Vr with the output voltage value Vw from the sample hold circuit 21, and outputs a low-level contact signal “L” if Vr> Vw and Vr <Vw. If it is, a high-level non-contact signal “H” is output.

The hot wire TIG welding apparatus uses a contact detection circuit incorporated in the wire heating power supply control circuit shown in FIG. 1 of the drawing attached to the specification of Japanese Patent Application No. 61-30649. You can also

When the welding control section 11 receives the contact signal "L", the welding control section 11 switches the built-in arc start switch to stop the power supply section 1 and bring the entire apparatus into the welding stop state. By doing so, it is possible to prevent spark discharge from occurring between the tungsten electrode 6 and the filler wire 8, so that it is possible to prevent inconvenience due to melting and scattering of the filler wire 8. In addition, the welding control unit 11
Responds to the contact signal “L”, reversely drives the wire feeding unit 9 via the wire feeding control unit 10, separates the filler wire 8 from the base material 5, and then activates the power supply unit 1 to start an arc. It is also possible to do so. By doing so, the welding work can be continued regardless of whether the filler wire 8 is in contact with the base material 5, so that the workability can be prevented from deteriorating and a spark is generated between the tungsten electrode and the base material. Since the discharge and arc can be generated correctly, there is no melting or scattering of the filler wire,
A weld of good quality can be obtained.

Hereinafter, the operation of the filler wire supply TIG welding apparatus configured as described above will be described with reference to FIGS. 3 and 4.

FIG. 3 is an operation explanatory view when the filler wire 8 is separated from the base material 5 immediately before the arc start.
In this case, the wire terminal voltage Vw has a value of 0 V or more, as shown on the left side of FIG. When such a state is detected by the contact detection circuit 20, the welding control unit 11 activates the power supply unit 1 to cause the TIG between the base metal 5 and the tungsten electrode 6 as shown on the left side of FIG. An arc current is applied to start an arc. Next, the welding control unit 11 activates the wire feeding unit 9 via the wire feeding control unit 10 as shown on the left side of FIG. 3C, and starts supplying the filler wire 8 to the welding unit. This starts welding work. After the welding work is started, the filler wire 8 comes into contact with the base material 5, so that the wire terminal voltage Vw becomes 0 V as shown in the intermediate portion of FIG. When the welding is completed, first, the wire feeding unit 9 is stopped as shown on the right side of FIG. By this, the filler wire 8
3A is separated from the base material 5, and the wire terminal voltage Vw becomes a value of 0 V or more as shown on the right side of FIG. When this is detected by the contact detection circuit 20, the welding control unit 11 stops the power supply unit 1 and stops the application of the TIG arc current, as shown on the right side of FIG.

FIG. 4 is an operation explanatory view when the filler wire 8 is in contact with the base material 5 immediately before the arc start.
In this case, the wire terminal voltage Vw is 0 V, as shown on the left side of FIG. When such a state is detected by the contact detection circuit 20, the welding control unit 11
Can stop the power supply unit 1 and stop the welding work, or can reverse the wire feeding unit 9 to separate the filler wire 8 from the base material 5 and then continue the welding work. . When continuing the welding work,
As shown in the central part of (c), the wire feeding part 9 is driven in reverse to separate the filler wire 8 from the base material 5. Filler wire 8
The wire feeding unit 9 is stopped at a stage when the wire is separated from the base material 5 by a predetermined amount. As a result, the wire terminal voltage Vw becomes a value of 0 V or more, as shown in the central portion of FIG. The welding control unit 11 detects this by the signal from the contact detection circuit 20, and starts an arc as shown on the right side of FIG. 4B. Next, the welding control section 11 starts the supply of the filler wire 8 to the welding section as shown on the right side of FIG. 4 (c). This starts welding work. Since the filler wire 8 comes into contact with the base material 5 after the start of the welding operation, as shown in FIG.
As shown on the right side of (a), the wire terminal voltage Vw becomes 0V.

In the above embodiment, the welding apparatus provided with a so-called integrated TIG torch has been described as an example, but as shown in FIG. 5, the contact tip 22 for guiding the filler wire 8 has the TIG torch 4. The same can be applied to a welding device configured separately from the above.

The present invention can be applied not only to the hot wire TIG welding apparatus but also to the cold wire TIG welding apparatus.

[0024]

As described above, according to the present invention, when the contact detection circuit detects that the base material and the filler wire are in contact with each other immediately before the arc start, the power supply unit is stopped and the entire apparatus is welded. Since the suspended state is set, no spark discharge is generated between the tungsten electrode and the filler wire, and it is possible to prevent the occurrence of inconvenience caused by the melting and scattering of the filler wire. In a similar situation, if the wire feeding part is driven in reverse and the filler wire is separated from the base material and then the power supply part is activated to start an arc, whether the filler wire is in contact with the base material or not. Welding work can be continued regardless of whether the workability is reduced or not, and spark discharge and arc can be correctly generated between the tungsten electrode and the base material. It is possible to obtain a good quality weld without any occurrence.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a welding device according to an embodiment.

FIG. 2 is a block diagram of a contact detection circuit.

FIG. 3 is an operation explanatory view of the welding device according to the embodiment.

FIG. 4 is an operation explanatory view of the welding device according to the embodiment.

FIG. 5 is a configuration diagram of a welding device according to another embodiment.

FIG. 6 is a configuration diagram of a welding device according to a conventional example.

FIG. 7 is a cross-sectional view of essential parts showing another example of a welding device according to a conventional example.

[Explanation of symbols]

 1 Power Supply Section 4 TIG Torch 5 Base Material 6 Tungsten Electrode 7 Arc 8 Filler Wire 9 Wire Feeding Section 10 Wire Feeding Control Section 11 Welding Control Section 20 Contact Detection Circuit

Claims (2)

[Claims] 1. A power supply unit for supplying a TIG arc current,
In a filler wire supply TIG welding apparatus including a filler wire feeder for feeding a filler wire and a controller controlling the power source portion and the filler wire feeder, it is detected whether or not the filler wire is in contact with a base material. A filler wire supply TIG welding apparatus, characterized in that a contact detection circuit is provided, and when the filler wire is in contact with the base material immediately before the arc start, the power supply unit is controlled by the control unit so as to stop the arc start. . 2. A power supply unit for supplying a TIG arc current,
A filler wire supply TIG welding apparatus including a filler wire feeder for feeding a filler wire and a controller controlling the power source portion and the filler wire feeder detects whether the filler wire is in contact with a base material. A contact detection circuit is provided, and when the filler wire is in contact with the base material immediately before the arc start, the filler wire feeding section is reversely driven to separate the filler wire from the base material, and then the power supply section and the power source section are connected so as to start the arc. A filler wire supply T characterized by controlling a filler wire feeder
IG welding equipment.