JP2000084669A - Method and device for controlling arc length of multi- electrode tig welding torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of the short circuit of electrodes and the phenomenon of an excessive arc length by monitoring the variation in voltage of two electrodes simultaneously. SOLUTION: A variation from the set electric power of the two electrodes in a TIG welding torch 10 is determined by a first and a second variation measuring apparatus 20a, 20b. Both variations are added by an adder 21 and, if the sum is in excess of a tolerance, a correction is calculated by multiplying a correction constant by a correcting device 22. With the correction value sent to an operation command device 18, a torch moving unit 17 is driven, making the TIG welding torch 10 close to or separate from the base material, thereby holding the arc length properly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling an arc length of a multi-electrode TIG welding torch capable of welding a large current.

[0002]

2. Description of the Related Art In recent years, in a TIG welding torch used for performing groove welding by abutting members such as a plate material, an electrode has a multi-electrode structure so that a large current can flow and high-speed welding can be performed. What has been developed.

[0003] Among the TIG welding torches having the above-mentioned multi-electrode structure, the one developed for a narrow groove is shown in FIG.
As shown in (b), flat grooves 2a and 2b are provided along both sides of the elongated flat insulating plate 1 in the longitudinal direction, and the flat grooves 2a and 2b are respectively connected to different power supplies. The first electrode 3a and the second electrode 3b made of tungsten, which are formed in a strip shape, are fitted in a side-by-side state.
The insulating plate 1 is sandwiched between the electrodes 3a and 3b, and the welding wire 4 is inserted into the boundary between the rear end surface of the insulating plate 1 and the wire guide 1a made of an insulator abutting the rear end surface. An electrode structure 5 having a flat cross-sectional shape is formed, and the electrode structure 5 is supported by a torch main body 7 via a power supply collet 6 and the electrode structure 5
A gas cup 9 for ejecting the shielding gas 8
The TIG welding torch 10 is configured to protrude from the tip of the TIG by a required length.

In a TIG welding torch having a single electrode structure, an AVC (arc voltage stage) is usually used.
(control) is performed. This is to automatically keep the torch close to and away from the base material according to the set voltage so that the length of the arc emitted between the electrode and the base material is kept constant. Thereby, stable welding can be performed, and a smooth bead can be formed, and welding accuracy can be improved. Therefore, such an arc length control method is referred to as the multi-electrode TI.
Application to the G welding torch 10 is conceivable.

[0005]

However, when the arc length control method of the TIG welding torch having a single electrode structure is applied to the TIG welding torch 10 having a multi-electrode structure, control is performed based on the voltage of one of the electrodes 3a or 3b. Therefore, it is assumed that the arc length becomes excessive or the electrodes are short-circuited.

More specifically, a thick plate 1 as shown in FIG.
When the lateral groove 12 formed between the TIG welding torches 10 is welded laterally, the entire TIG welding torch 10 is arranged laterally so that both electrodes 3a and 3b are arranged vertically, and the electrode structure is placed in the lateral groove 12. 5 is inserted and a voltage is applied to both electrodes 3a and 3b to move the electrode along the lateral groove 12. In the welding of the lateral groove 12, gravity is applied to the molten metal 13. Therefore, in the case of one-layer one-pass, an overlap portion 14 is generated on the lower wall 12a side of the groove 12 due to the dripping of the molten metal 13.

At this time, for example, when the arc length control is performed based on the first electrode 3a located on the upper side, the second electrode 3b located on the lower side comes into contact with the overlap portion 14 so that the second electrode 3b is formed. If the arc length control is performed based on the second electrode 3b located on the lower side, the arc length of the first electrode 3a located on the upper side becomes excessively large, and the groove 12 may be formed. There is a possibility that the undercut portion 15 may be generated on the upper wall 12b side of the first embodiment.

Therefore, according to the present invention, the arc length can be appropriately controlled by simultaneously monitoring the voltage fluctuations of the two electrodes and adjusting the voltage so that short-circuit development of the electrodes and excessive development of the arc length do not occur. It is an object of the present invention to provide a method and an apparatus for controlling the arc length of such a multi-electrode TIG welding torch.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for welding a base material using a multi-electrode TIG welding torch having two electrodes, a first electrode and a second electrode, arranged in parallel. In the method for controlling the arc length of a multi-electrode TIG welding torch for maintaining the length of the arc emitted between the base material and the base material based on the set voltage to the two electrodes, Variation values are obtained and added, respectively, and then a correction value is calculated by multiplying the added value by a correction constant.Based on the correction value, the welding torch is moved closer to or away from the base material to determine the arc length. A method for controlling the arc length of a multi-electrode TIG welding torch to be controlled, and a voltage for setting the voltage of the two electrodes of a multi-electrode TIG welding torch having two electrodes, a first electrode and a second electrode, arranged in parallel Controller and the voltage set by the voltage controller A multi-electrode TIG welding torch arc length control device, comprising: a driving command to the torch moving unit to maintain the length of the arc emitted from the base material. A first voltage measuring device for measuring the voltage of the second electrode, a second voltage measuring device for measuring the voltage of the second electrode, a first fluctuation value measuring device for determining a difference between a measured value of the first voltage measuring device and a set voltage, A second fluctuation value measuring device for obtaining a difference between a measured value of the second voltage measuring device and a set voltage, and an adder for adding a fluctuation value of the first fluctuation value measuring device and a fluctuation value of the second fluctuation value measuring device. An arc length control device for a multi-electrode TIG welding torch, comprising a corrector for sending the operation commander to a correction value obtained by multiplying the addition value obtained by the adder by a correction constant.

At the time of welding, a variation value from the set voltage of the first electrode and the second electrode is obtained and added, and a correction value is calculated by multiplying the added value by, for example, 1/2 as a correction constant. By moving the welding torch closer to or away from the base material based on the value, both electrodes are controlled to have an appropriate arc length with respect to the base material. Therefore, even in the case of horizontal welding, it is possible to prevent the occurrence of an overlap portion or an undercut portion.

In addition, the operation mode of the first electrode and the second electrode alone is added to the voltage controller, and the first fluctuation value measuring device and the second
In the case where the apparatus is provided with a function of sending the fluctuation value measured by the fluctuation value measuring device as a correction value to the operation command device, the mode selection selects the voltage fluctuation value of either the first electrode or the second electrode as a reference. The arc length will be controlled. Therefore, it is advantageous when applied to downward welding.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of an apparatus for controlling the arc length of a multi-electrode TIG welding torch according to the present invention.
(A) A multi-electrode T having the same configuration as shown in (b)
A voltage controller 16 for setting the voltage applied to the two electrodes 3a and 3b of the IG welding torch 10, and a drive command is given to a torch moving unit 17 based on the voltage set by the voltage controller 16 so that the welding torch 10 is In an arc length control device for a multi-electrode TIG welding torch provided with an operation command device 18 which is adapted to keep the arc length constant by moving toward and away from the base metal, a voltage for measuring the voltage of the first electrode 3a is measured. A first voltage measuring device 19a, a second voltage measuring device 19b for measuring the voltage of the second electrode 3b, and a first fluctuation value measuring device for obtaining a fluctuation value as a difference between a value measured by the first voltage measuring device 19a and a set value. 20a, a second fluctuation value measuring device 20b for obtaining a fluctuation value as a difference between the value measured by the second voltage measuring device 19b and the set voltage, a fluctuation value obtained by the first fluctuation value measuring device 20a and the second fluctuation value Dochi measuring instrument adder 21 for adding the variation value obtained in 20b, the adder 21 obtained in added value to the obtained by multiplying the correction constant correction value the operation command unit 1
8 is provided with a compensator 22.

By controlling the arc length of the TIG welding torch 10 by the arc length control device having the above configuration,
For example, when welding the lateral groove 12 formed between the thick plates 11 as shown in FIG. 6, the fluctuation values from the set voltages of the two electrodes 3a and 3b are obtained and added, and the added value is added to this value. A correction value is calculated by multiplying the correction constant, and based on the correction value, the TIG welding torch 10 is moved toward and away from the lateral groove of the thick plate 11 as a base material.

More specifically, referring to the flow charts of FIGS. 1 and 2, first, the voltage controller 16 controls the first electrode 3a and the second electrode 3a.
When welding is started by setting the set voltages S1 and S2 of b,
Arc length control is started. In this case, for example, the first
The set voltage S1 of the electrode 3a and the set voltage S2 of the second electrode 3b
Is sent to the operation command unit 18 and used as a reference for the arc length control.

When welding is started, the voltage of the first electrode 3a during the welding operation is measured by the first voltage measuring device 19a,
The voltage of the second electrode 3b is measured by the second voltage measuring device 19b. Next, the first fluctuation value measuring device 20a compares the measurement value S1 'measured by the first voltage measuring device 19a with the set voltage S1, thereby obtaining a fluctuation value ΔS1 as the difference between the measured value S1' and the second fluctuation value ΔS1. Similarly, in the fluctuation value measuring device 20b, the measured value S2 'of the second voltage measuring device 19b and the set voltage S2
Are compared with each other to obtain a variation value ΔS2 as the difference.
Is required.

Next, the obtained fluctuation values ΔS1 and ΔS2
Is added to the adder 21, and if the added value ΔS is within the allowable range, welding is continued with the same arc length. On the other hand, as shown in FIG. 6, when the overlap portion 14 and the undercut portion 15 occur in the lateral groove 12, the variation values ΔS1 and ΔS2 become large.
The added value ΔS added at 1 exceeds the allowable range. Therefore, in such a case, the addition value ΔS is sent to the corrector 22, where the correction value ΔS ′ is calculated by multiplying by, for example, 、 as a correction constant, and the correction value ΔS ′ is calculated. The set voltage S is corrected by being sent to the operation command device 18. Therefore, as a result of correcting the drive command sent from the operation command unit 18 to the torch moving unit 17, the TIG welding torch 10 is moved closer to or away from the lateral groove 12, and the arc length is set to an appropriate length. Will be controlled. This allows
The first electrode 3a and the second electrode 3b do not short-circuit with the base material side, and the arc length can be prevented from becoming excessive.

Next, FIG. 3 shows another embodiment of the present invention. In a configuration similar to that shown in FIG. 1, only the first electrode 3a and the second electrode 3b are provided to the voltage controller 16. And the first variation value measuring device 20
a, the fluctuation value ΔS1, measured by the second fluctuation value measuring device 20b,
When ΔS2 exceeds the allowable range, these fluctuation values Δ
It has a function of directly sending S1 and ΔS2 to the operation command device 18 as correction values.

When the arc length control device is constructed as shown in FIG. 3, the voltage controller 16 as shown in the flow chart of FIG.
The first electrode 3a is used as an electrode for controlling the arc length.
Combination of the second electrode 3b or only the first electrode 3a,
Alternatively, only the second electrode 3b can be selected, and the first
When the mode of only the electrode 3a or only the second electrode 3b is selected, in the flow of FIG. 4, after the fluctuation value is measured, control is performed along a path shown by a broken line. Therefore, as in the above-described embodiment, the arc length control is performed based on both the voltage fluctuation values of the electrodes 3a and 3b during the horizontal welding, and based on the voltage fluctuation value of only the electrode 3a or 3b during the downward welding.
Multi-electrode control or single-electrode control can be selected and used according to the shape of the groove or the torch posture.

In this embodiment, the case where 1/2 is used as the correction constant of the corrector 22 has been described. However, an arbitrary numerical value can be selected according to the shape of the base material and the molten pool. It goes without saying that various changes can be made without departing from the spirit of the present invention.

[0021]

As described above, the multi-electrode TIG of the present invention
According to the method and apparatus for controlling the arc length of a welding torch,
At the time of welding a base material by a multi-electrode TIG welding torch having two electrodes, an electrode and a second electrode, arranged in parallel, the base material and the base material are set on the basis of the set voltage to the two electrodes set by the voltage controller. Electrode TIG which keeps the length of the arc emitted to
In the method and apparatus for controlling the arc length of a welding torch, a fluctuation value from the set voltage of the two electrodes is obtained by a fluctuation value measuring device, added by an adder, and a correction constant is added to the added value by a corrector. The arc length is controlled by moving the TIG welding torch to and away from the base metal by controlling the arc length by sending the correction value to the calculation commander. It is possible to prevent the arc from being excessively developed, and to add a function of adding an operation mode of the first electrode or the second electrode alone and using a voltage fluctuation value of the first electrode or the second electrode as a correction value. Thereby, the arc length control can be performed in various modes, and excellent effects such as the control according to the shape of the base material can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an arc length control device for a multi-electrode TIG welding torch according to the present invention.

FIG. 2 is a flowchart based on the block diagram of FIG. 1;

FIG. 3 is a block diagram showing another embodiment of the present invention.

FIG. 4 is a flowchart based on the block diagram of FIG. 3;

FIG. 5 shows an example of a TIG welding torch.
Is a schematic side view, and (b) is an enlarged view in the direction of arrows A-A in (a).

6 is a schematic view showing an example of a use state of the TIG welding torch shown in FIG.

[Explanation of symbols]

 3a 1st electrode 3b 2nd electrode 10 TIG welding torch 16 voltage controller 17 torch moving unit 18 operation commander 19a 1st voltage measuring device 19b 2nd voltage measuring device 20a 1st fluctuation value measuring device 20b 2nd fluctuation value measuring device 21 adder 22 compensator

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Kazuyuki Kobayashi 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Technical Research Institute, Ishikawajima-Harima Heavy Industries, Ltd. (72) Hideto Nakatani Hideto Nakatani, Isogo-ku, Yokohama-shi, Kanagawa 1 Nakahara-cho Ishi Kawashima-Harima Heavy Industries, Ltd. Technical Research Institute (72) Inventor Kimi Fujishima 1 Shinkahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Ishikawashima-Harima Heavy Industries Co., Ltd. F-term (reference) QA01 QA04

Claims (3)

[Claims] At the time of welding a base material by a multi-electrode TIG welding torch having two electrodes, a first electrode and a second electrode, arranged in parallel, the base material is connected to the base material based on a set voltage to the two electrodes. In a method for controlling the arc length of a multi-electrode TIG welding torch that maintains the length of the arc emitted between the two electrodes, the fluctuation values from the set voltages of the two electrodes are obtained and added, and then the added value is calculated. A multi-electrode TI which calculates a correction value by multiplying the correction constant, and controls the arc length by moving the welding torch closer to or away from the base material based on the correction value.
An arc length control method for a G welding torch. 2. A voltage controller for setting voltages of the two electrodes of a multi-electrode TIG welding torch having two electrodes, a first electrode and a second electrode, arranged in parallel, and a voltage set by the voltage controller. A multi-electrode TIG welding torch arc length control device, comprising: a driving command to a torch moving unit based on the above, and an operation command device configured to maintain a length of an arc emitted from the base material. First to measure electrode voltage
A voltage measuring device, a second voltage measuring device for measuring the voltage of the second electrode, a first fluctuation value measuring device for calculating a difference between a measured value of the first voltage measuring device and a set voltage, and a second voltage measuring device A second variation value measuring device for determining a difference between a measured value and a set voltage,
An adder for adding a variation value obtained by the variation value measuring device and a variation value obtained by the second variation value measuring device; and a correction value obtained by multiplying the addition value obtained by the adder by a correction constant to the arithmetic command device. An arc length control device for a multi-electrode TIG welding torch, characterized by having a configuration including a compensator for feeding. 3. An operation mode of the first electrode and the second electrode alone is added to the voltage controller, and a fluctuation value measured by the first fluctuation value measuring device and the second fluctuation value measuring device is calculated as a correction value. 3. The multi-electrode TIG according to claim 2, wherein the multi-electrode TIG has a function of sending to a command device.
Arc length control device for welding torch.