JPH07314139A - Method and controller for groove copying in electrode rotating type non-consumable electrode arc welding - Google Patents

Abstract

PURPOSE:To execute weld line automatic copying excellent in precision without use of a sensor by comparing the difference of respective integrated values of arc voltage wave form at the rotating position of electrode in the left/right prescribed range, based on the reference of the forward center of advancing direction of arc rotating circle parallel to the weld line of lapped part of thin sheet to the prescribed threshold. CONSTITUTION:Circle motion is given to the tip of non-consumable electrode 2 of a welding torch 12, low current and high current are made alternately and at a rotating unit of electrode 2 to flow through the welding torch, while rotating in high speed the arc generated at non-consumable electrode 2 in one direction and lap welding is executed along the weld line of the lapped part of thin sheet, the arc voltage is detected. Among these arc voltages, the arc voltages at a rotating position of electrode 2 in the two prescribed angle range of left/light >=5 deg. and <=180 deg., based on the reference of the forward center of advancing direction of arc rotating circle are compared. By moving/controlling the welding torch 12 in the direction perpendicular to the weld line so that a difference between integrated value and threshold value is made to zero, the welding torch is suitably controlled for the weld line of lapped part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to lap welding of thin plates, which is non-consumable such as TIG welding or plasma welding which does not use a filler material that forms beads by melting base materials on the upper and lower plates. In the electrode arc welding method, the welding line formed by the overlapping portion of the thin plates is automatically detected, and the torch is made to follow the welding line at an appropriate position to form a welding portion having a good bead surface shape and the bead surface shape. And the penetration of the base metal,
In particular, the present invention relates to a groove tracking method and a groove tracking control device in electrode rotary non-consumable electrode arc welding that ensures the stabilization of the penetration on the lower plate side.

[0002]

2. Description of the Related Art Conventionally, in a lap welding of thin plates, a torch follows a welding line by a manual operation of an operator, or a costly contact sensor is used for its detection, or a complicated image by an optical sensor is used. The processing method was adopted. In order to automate welding, the two methods described above are required, but in any case, in addition to the torch, a unique device called a sensor must be installed near the torch, so the detection position and control target Due to dimensional constraints, a certain distance was generated between the position and the position. Therefore, it is necessary to control the torch position by giving a time difference according to the interval, and it is possible to perform only the control with a limited accuracy for a complicated division. As a welding line profiling method which is excellent in accuracy without using a separate sensor, an arc sensor groove line profiling method using a welding arc itself as a sensor is disclosed in Japanese Patent Publication No. 61-17591.

This arc sensor groove line tracing method compares changes in arc characteristics due to torch oscillation within the groove with a half cycle of left and right oscillations with respect to the center of the oscillation width after time integration. However, the groove line tracing is achieved by controlling the movement of the torch swing center such that the two become equal, that is, the difference between the two becomes zero. But,
There is a drawback that it cannot be applied to joints where one groove is not present, such as the welding line of lap welds of thin plates.
In addition, Japanese Patent Publication No. 4875/1989 (Japanese Patent Laid-Open No. 57-91).
In the method disclosed in Japanese Patent No. 877)), a groove-following method in the case of rotating an electrode is also disclosed, but it can be applied only when the groove exists as described above.

[0004]

SUMMARY OF THE INVENTION In order to automate welding, a groove detecting sensor is provided for automatically controlling the torch position with respect to a two-dimensional deviation of the welding line which changes from moment to moment during welding. Also, a torch position movement adjusting mechanism using a detection sensor is required. Conventionally, following the torch to the welding line in the lap welding of thin plates is performed by the operation of the welding operator, or it is expensive to automate the welding, but a contact sensor is used for its detection, or it is complicated by an optical sensor. However, it is necessary to install a unique device such as another sensor in the vicinity of the torch in addition to the torch. There is a problem that there is a fixed interval due to constraints, and it is necessary to control the torch position by giving a time difference according to the interval, which is complicated, but only control with limited accuracy can be performed. Further, in lap welding of thin plates, it is required in non-consumable electrode arc welding methods such as TIG welding and plasma welding in which beads are formed by melting base materials on the upper and lower plates without using a filler metal. In order to obtain a good bead surface shape, the target position of the torch must always be kept at an appropriate position.

The present invention does not use a sensor as a separate body for a joint having only one groove, that is, a step like a welding line of a lap welding portion of a thin plate, and a welding line excellent in accuracy. Electrode rotating non-consumable electrode arc that can automatically keep the bead surface shape and the penetration of the base metal, especially the stabilization of the penetration on the lower plate side, and keep the bead surface shape of the lap weld appropriately. It is an object of the present invention to provide a groove copying method and a groove copying control device in welding.

[0006]

A groove tracing method in electrode rotating type non-consumable electrode arc welding according to the present invention provides a circular motion to a tip of a non-consumable electrode provided on a welding torch to apply the non-consumable electrode to the non-consumable electrode. While rotating the generated arc in one direction at high speed, lap welding is performed along the welding line of the lap portion of the thin plate.The arc voltage is detected during welding and the welding voltage of the lap portion of the thin plate The difference between the integral values of the arc voltage waveforms at the electrode rotation positions in the two predetermined angle ranges of 5 ° or more and 180 ° or less on the left and right of the front center of the traveling direction of the rotating circle of the parallel arc is set as a predetermined value. Compared with a threshold value, the welding torch is moved and controlled in a direction orthogonal to the welding line so that the difference becomes zero, and the welding torch is controlled to an appropriate position with respect to the welding line of the overlapping portion of the thin plate,
Furthermore, for each rotation of the welding torch, a predetermined welding angle range of 5 ° or more and 160 ° or less across the left and right sides of the backward center in the traveling direction of the arc rotation circle is set to a higher welding current than in other angle ranges. It was made to flow to.

Another groove-growing method in non-consumable electrode arc welding of the electrode rotating type according to the present invention provides a circular motion to the tip of the non-consumable electrode provided on the welding torch, and the welding torch has a unit of electrode rotation. Alternating high and low currents, the arc generated on the non-consumable electrode is rotated in one direction at high speed to perform lap welding along the welding line of the lap portion of the thin plate. The arc voltage is detected when either an electric current or a high current is applied, and the left and right of the arc voltage are measured with respect to the forward center of the traveling direction of the arc of rotation of the arc parallel to the welding line of the thin plate overlap. The difference between the integrated values of the arc voltage waveforms at the electrode rotation positions in the two predetermined angle ranges of 5 ° or more and 180 ° or less is compared with a predetermined threshold value, and the welding torch is set so that the difference becomes zero. The welding line The welding torch is controlled to a proper position with respect to the welding line of the overlapping portion of the thin plates by controlling movement in a direction orthogonal to the above.

Further, the groove-contour control device in the electrode rotating type non-consumable electrode arc welding according to the present invention includes a welding power source device for outputting a predetermined welding current and a welding current according to a command, and a welding power source. The arc voltage detector that detects the arc voltage between the welding torch electrode and the workpiece to be welded by the power supplied from the device, the rotation position detector that detects the rotation angle position of the electrode, and the detection signal of the arc voltage detector are Timing of outputting a signal for operating the integrator with respect to the detection signals of the two predetermined angle ranges preset based on the position detection signal of the rotational position detector among the detection signals of the input integrator and the arc voltage detector A circuit, a first comparator for obtaining a difference between integrated values of detection signals in two predetermined angle ranges respectively output from the integrator, and a welding torch in a direction orthogonal to a welding line A torch aiming position setter that outputs a reference value to be set at a predetermined position near the welding line, and a difference between the difference between the integrated values output from the first comparator and the reference value of the torch aiming position setter Drive for driving and controlling the welding torch in the direction orthogonal to the welding line so that the difference becomes zero based on the difference between the integrated value output from the comparator and the reference value output from the second comparator. Based on the position detection signal of the control unit and the rotational position detector, a predetermined output signal is output only for a predetermined angle range preset for each rotation of the electrode, or a predetermined output is provided for every other rotation of the electrode for each rotation of the electrode. Current switching timing circuit that outputs an output signal of, a current setting device that sets a high current value so that the welding power source device outputs a high output current, and when an output signal from the output current switching timing circuit is received. Current setting device A command value of the high current is constituted by a switching device to be output to the welding power supply.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the whole of a groove-tracing control device according to a first embodiment of the present invention, FIG. 2 is a sectional view showing an electrode rotary TIG torch of an electrode rotary TIG welding device, and FIG. FIG. 4 is a schematic diagram showing a scanning signal detection method of the preceding scanning method, and FIG. 4 is an explanatory diagram showing a difference in bead shape depending on the aiming position. In the figure, 1 is a base material in which an upper plate 1b is superposed on a lower plate 1a which is a material to be welded, 2 is a tungsten electrode which is a non-consumable electrode positioned on a groove line of the base material 1, and 3 is a rotary drive motor Three
Reference numeral a is a shaft of the rotary drive motor 3, 4 is a drive gear attached to the shaft 3a, and the rotary drive motor 3 gives a high speed rotation, 5 is a driven gear which is given a high speed rotation by the drive gear 4, and 6 is a tungsten electrode 2. A cylindrical electrode holding member held by a collet chuck 6a provided at the tip, and 6b is a gas cup provided below the electrode holding member 7 and surrounding the tungsten electrode 2.

Reference numeral 7 denotes an upper self-aligning bearing that rotatably supports the upper portion of the electrode holding member 6, and 8 holds the upper self-aligning bearing 7 eccentrically by a certain amount from the center of rotation of the ring, that is, the upper portion of the electrode holding member 6. Is an eccentric ring that holds a certain amount of eccentricity from the rotation center of the driven gear 5, and the upper self-aligning bearing 7 constitutes an eccentric ring member. 9
Is an eccentric ring holding case that houses the eccentric ring 8 integrally, and is integrally attached to the driven gear 5. 10
Is a lower self-aligning bearing that supports the lower portion of the electrode holding member 6. 11 is the rotational angle position of the rotary drive motor 3,
That is, it is a rotational position detector such as an encoder for detecting the rotational angular position of the tip of the tungsten electrode 2. A welding voltage is applied by a constant current welding power supply device, which will be described later, between the tungsten electrode 2 held by the electrode holding member 6 and located on the axis of the electrode holding member 6, and the base material 1 to generate an arc.
Reference numeral 12 is an electrode rotating TIG torch composed of a tungsten electrode 2 and a rotary position detector 11.

Reference numeral 12 denotes an electrode rotary TIG torch of the electrode rotary TIG welding apparatus, which is composed of the tungsten electrode 2 to the rotary position detector 11 shown in FIG. Reference numeral 13 is a welding power supply device that outputs a predetermined welding current and that outputs a welding current according to a command, and a constant current welding power supply device 14 is an arc voltage detector that detects an arc voltage between the tungsten electrode 2 and the base metal 1, Reference numeral 15 is a rotation speed setting device for rotating the tungsten electrode 2 at a desired rotation speed, and 16 is a rotation speed setting device 1.
5 is a rotation motor driver that drives the rotation drive motor 3 based on the rotation speed setting value set by 5.

Reference numeral 17 is an arc voltage reference setting device for setting a reference arc voltage between the tungsten electrode 2 and the base metal 1, and 18 is a difference between a detection value of the arc voltage detector 14 and a reference value of the arc voltage reference setting device 17. A differential amplifier for comparison calculation, 19 is a lifting motor controller that controls the rotation of the lifting motor 21 of the torch lifting mechanism 20 based on the output of the differential amplifier 18, and 22 is a lateral movement motor 24 of the torch lateral movement mechanism 23.
A horizontal movement mechanism controller for controlling the rotation of the torch elevating mechanism 20 and a welding carriage 25 that supports the torch vertical movement mechanism 23 and the torch horizontal movement mechanism 23 and travels on the base material 1.

Reference numeral 26 is a timing circuit for outputting a signal for operating the integrator with respect to the detection signals in the two predetermined angle ranges preset based on the position detection signal of the rotational position detector 11, and 27a and 27b are arc voltage detectors 14. Of the arc voltage detection signal and the timing circuit 26
The integrator to which the signal from is also input, 28 is an integrator 27a,
A first comparator for obtaining a difference between integrated values output from 27b,
29 is a torch aiming position setting device that outputs a reference value for setting the welding torch at a predetermined aiming position near the welding line in the direction orthogonal to the welding line, and 30 is the difference between the integrated value output from the first comparator 28 and the torch. A second comparator 31 for obtaining a difference from the reference value of the target position setting device 30, 31 is set so that the difference becomes zero based on the difference between the integrated value output from the second comparator 30 and the reference value. Is a welding line tracing control circuit that outputs a control signal to the lateral movement mechanism controller 22. 32 is the timing circuit 2
6 to a copying drive control circuit including a welding line copying control circuit 31.

Reference numeral 33 is a current switching timing circuit which outputs an output signal at a predetermined timing based on the position detection signal of the rotational position detector 11, and 34 is a high current so that the constant current welding power source device 13 outputs a high output current. A current setting device 35 for setting a value is a switching device for outputting a high current command value set by the current setting device 34 to the constant current welding power supply device 13 when receiving an output signal from the current switching timing circuit 33. .

Next, the operation of the above embodiment will be described. First,
The operation of the electrode rotating TIG torch 12 of the embodiment shown in FIG. 2 will be described. When the rotary drive motor 3 rotates, the rotation is transmitted to the eccentric ring 8 via the drive gear 4, the driven gear 5 and the eccentric ring holding case 9. The eccentric ring 8 rotatably holds the upper self-aligning bearing 7 that rotatably supports the upper portion of the electrode holding member 6 at an eccentric position that is apart from the ring rotation center by a certain distance.
As the eccentric ring 8 rotates, the upper part of the gyro rotates about its rotation axis. Further, the lower part of the electrode holding member 6 is also coaxially attached to the center of rotation of the eccentric ring 8 and is also held by the lower self-aligning bearing 10 fixed at the periphery thereof. Due to the action with the ring 8, the tip of the tungsten electrode 2 extending downward from the lower portion of the electrode holding member 6 makes a sleek-shaped circular motion with the lower self-aligning bearing 10 as the fulcrum of the rotation center.

When the tip of the tungsten electrode 2 makes a circular motion, the lower part of the electrode holding member 6 holding the base of the tungsten electrode 2 is rotatably supported by the lower self-aligning bearing 10 and the center of rotation is Since it does not rotate itself, power can be directly supplied to the tungsten electrode 2 located below the electrode holding member 6 by a power supply cable (not shown). It should be noted that the upper self-aligning bearing 7 and the lower self-aligning bearing 10 may be replaced by a spherical bearing, a unit ball bearing, or another free bearing having the same function.

Next, the operation of the electrode rotary TIG welding apparatus will be described. For example, when laminating stainless steel thin plates with a thickness of 2 mm, the electrode rotation diameter of the non-consumable tungsten electrode 2 is 2.5 mm, the electrode rotation frequency is 3 to 5 Hz by the rotary drive motor 3, and constant current welding is performed. The welding current is 100 A to 150 A by the device 13,
Circular motion is applied to the tip of the tungsten electrode 2, and the arc generated in the tungsten electrode 2 is rotated at high speed, and lap welding is performed along the welding line of the base material 1 at a welding speed of 25 to 30 cm / min. At this time, the torch tilt angle is held at an appropriate value within 0 ± 10 °.

When the torch was stationary, the arc was concentrated at one point on the weld and the area immediately below the arc was always melted, but the tip of the tungsten electrode 2 was mechanically formed into a circular shape while generating the arc. Since the welding is performed by moving, the welding arc is applied to the welded portion of the base material 1 with the tungsten electrode 2
As the tip of the arc rotates, the welded part moves in a circular shape, and the melted part just below the arc moves at a certain rotation diameter, and the heat input to the welded part of the arc is dispersed in a certain diameter. Next to
As a result, a wide-width, shallow-penetration welded portion can be formed efficiently at high speed.

In terms of the characteristics of the TIG arc, the effect of the rotation of the tungsten electrode 2 is determined by whether the arc can move in the molten portion with the rotation. In the case of the TIG arc, the electrode rotation frequency is about 20 Hz. It is the limit.
Further, the effect of dispersing the heat input is seen at a certain rotation diameter or more, and the maximum value of the rotation diameter is determined by the drastic reduction in the melting efficiency of the base material due to the heat input dispersion. When the welding current used in the lap welding of thin plates is a dozen A to two hundred and several tens A, a proper range of the rotating diameter is about 1 to 4 mm. Then, the appropriate range of this rotation diameter depends on the value of the welding current used.

Next, a groove line tracing method according to the second embodiment of the present invention will be described with reference to FIGS. 1, 3 and 5. First, the principle of the groove line tracing method will be described. Welding is performed along the welding line of the base material 1 including the lower plate 1a and the upper plate 1b on which the tungsten electrode 2 provided on the electrode rotating TIG torch 12 is lap-welded. Then, as shown in FIG. 3A, the tip of the tungsten electrode 2, that is, the arc is a rear center C.I. in the traveling direction of the rotating circle R of the arc. When the point A, which is the R position, is reached to the point B on the lower plate 1a side, the arc voltage detected by the arc voltage detector 14 at the rotational position on the lower plate 1a side gradually rises as shown in FIG. 3B. Then B
At this point, the increase in arc voltage is almost maximum. After that, from the point B, the forward center C.C. The arc voltage gradually decreases as it reaches the point C which is the F position, and when the arc further rotates and comes from the point C to the point D on the upper plate 1b side, the arc voltage is detected at the rotating position on the upper plate 1b side. The arc voltage detected by the container 14 gradually decreases, and the decrease of the arc voltage becomes almost maximum at the point D. After that, the arc voltage rises from point D to point A.

FIG. 3B shows changes in the arc voltage with reference to the reference voltage.
SR is the forward center C.I. in the traveling direction of the rotating circle R of the arc shown in FIG. It is a representation of integrated values of two predetermined angle ranges θ1 and θ2 of 0 ° to 90 ° (R region) and 270 ° to 360 ° (L region) on the left and right with F as a reference. Therefore,
By detecting the arc voltages on the lower plate 1a side and the upper plate 1b side of the rotating tungsten electrode 2, respectively, and comparing the two voltages, the center of the rotating circle R at the tip of the tungsten electrode 2 becomes the welding line of the base metal 1. You can see if it is located. Therefore,
By detecting the arc voltage between the lower plate 1a side and the upper plate 1b side, comparing the detected voltages to obtain the difference, and comparing the difference with a reference value set so that the welding line position can be detected. It can be seen whether or not the center of the rotating circle at the tip of the tungsten electrode 2 is located at the welding line of the base material 1.

Next, the groove line tracing method according to the present invention will be described. Lower plate 1a and upper plate 1b to which the tungsten electrode 2 provided on the electrode rotating TIG torch 12 is overlap-welded
When welding is performed along the welding line of the base material 1 consisting of and, the arc voltage detector 14 detects the arc voltage which is changing due to the rotation of the tip of the tungsten electrode 2 and inputs it to the integrators 27a and 27b. ing. On the other hand, the rotational position detector 11 detects the rotational position of the rotating tungsten electrode 2 and outputs a position detection signal to the timing circuit 26. Then, in the timing circuit 26, the rotational position detector 1
Based on the position detection signal of No. 1, a 45 ° angle range θ1 of 45 ° to 90 ° on the lower plate 1a side and a 45 ° angle range θ1 of 180 ° to 225 ° on the upper plate 1b side set in advance. In, the integrators 27a and 27b integrate the arc voltage.

The integrated value obtained by integrating the arc voltage by the integrators 27a and 27b is input to the first comparator 28. The reason why the integrators 27a and 27b perform the integration in this way is to prevent the arc voltage waveform from being affected by noise. In the first comparator 28, the integrated value SL by the integrator 27a
And 27b, the difference ΔS between the integrated values SR is obtained,
Output to the comparator 30. The second comparator 30 uses the difference between the integrated values obtained by the first comparator 28 and the torch aiming position setter 30.
The signal of the difference is output to the welding line tracing control circuit 31. The welding line copying control circuit 31 outputs a lateral movement command signal to the lateral movement mechanism controller 22 so that the difference obtained by the second comparator 30 becomes zero. The lateral movement mechanism controller 22 rotates the lateral movement motor 24 to drive the torch lateral movement mechanism 23 to drive the electrode rotation TIG.
The torch 12 is controlled to move in a direction orthogonal to the welding line so that the electrode rotating TIG torch 12 comes to the welding line of the overlapping portion of the thin plates, that is, the center of the rotating circle of the tip of the tungsten electrode 2 is located at the welding line. In addition, the electrode rotating TIG torch 12 is controlled to an appropriate position.

The torch aiming position setter 30 sets the reference value to 0 V at the aiming position A shown in FIG. 4 in which the tip of the tungsten electrode 2, that is, the center of the arc of rotation is located at the welding line. It is set, and the center of the arc of rotation of the arc is in the direction orthogonal to the welding line, and the target position B shown in FIG.
When it comes to the position of, the reference value is 0.7
V, when it comes to the position of the target position C shown in FIG. 4, the reference value may be set to 1.0 V, for example. Therefore,
It can be adjusted so that the arc is always properly located at the target position parallel to the welding line. In this way, the arc voltage during welding is detected, the arc voltage is signal-processed, the center of the arc of the arc is controlled to be located at the target position, and the electrode rotating TIG torch 12 is made to follow automatically. Therefore, the welding arc itself serves as a sensor, and the electrode rotating TIG torch 12 can be accurately followed along the welding line in the welding process.

In the above embodiment, the target position of the arc is delicate, and the bead shape may be deteriorated if it changes by 0.2 to 0.3 mm. Further, the target position also changes depending on the plate thickness, and the bead shape changes depending on the target position. It is desirable that the torch angle is approximately within ± 10 ° of vertical,
In the case of a thin plate having a thickness of about 0.5 to 2.5 mm, it is preferable that the aiming position for copying the welding line is about 0.5 to 0.8 mm on the upper plate side. Further, in the electrode rotating TIG torch 12, it is necessary to adjust the torch raising / lowering operation in order to prevent a short circuit of the tungsten electrode 2 to the base material 1. The adjustment of the ascending / descending operation of the electrode rotating TIG torch 12 during welding is performed by calculating the deviation between the arc voltage detection signal from the arc voltage detector 14 and the reference arc voltage of the arc voltage reference setter 17 by the differential amplifier 16, and the deviation. Is carried out by raising and lowering the electrode rotation TIG torch 12 by controlling the raising and lowering motor controller 19 to rotate the raising and lowering motor 21 so as to be always zero.

In the above embodiment, the target of the arc voltage integrated by the integrators 27a and 27b is 0 ° to 45 on the lower plate 1a side.
The angle range θ1 is 45 °, which is 45 °, and 3 on the upper plate 1b side.
Although the angle range θ2 is 45 ° which is 15 ° to 360 °, the angle range θ1 is 175 ° which is 5 ° to 180 ° on the lower plate 1a side, and the angle range θ1 is 180 ° to 355 ° on the upper plate 1b side.
It is needless to say that even with the angular range θ2 of 175 °, the center of the rotating circle R of the arc can be controlled so as to come to an appropriate position with respect to the welding line. In the above embodiment, the two integrators 27a and 27b are used, but one integrator respectively integrates the detection signals in the two predetermined angle ranges and outputs the two integrated values to the first comparator 28. Well,
In this case, one integrator is sufficient if the detection signal in one predetermined angle range is integrated, the value is transferred to the other, reset at high speed, and the detection signal in the other predetermined angle range is integrated.

In such electrode rotating TIG welding, the welding current is constant, and a wide-width and shallow-penetration welded portion can be obtained due to the effect of heat input dispersion by the rotation of the arc. However, depending on the object, deep penetration may be required on the lower plate 1a side together with the bead surface shape. In such a case, if the constant current welding condition of the electrode rotating TIG welding is set to a high current, the penetration increases, but the bead surface shape may deteriorate, and the stable welding conditions for various plate thicknesses are narrow. Is the current situation. Therefore, in order to solve this problem, the following is performed.

FIG. 5 is an explanatory view showing a groove copying method of a second embodiment according to the present invention, and FIG. 6 is an explanatory view showing a bead shape formed by the groove copying method of the same embodiment. In this embodiment, as shown in FIG. 5, the current switching timing circuit 33 generates an arc rotation circle R for each rotation of the tungsten electrode 2 of the electrode rotation TIG welding torch 12 based on the position detection signal of the rotation position detector 11. An output signal is output to the switch 35 with respect to a predetermined angle range θp of 90 ° extending to the left and right of the rear center CR in the traveling direction. On the other hand, the current setting device 34 outputs to the switch 35 a command of a high current value set so that the constant current welding power supply device 13 outputs a high output current.

Therefore, when the switch 35 receives the output signal from the current switching timing circuit 33, the current setter 3 receives the output signal.
The high-current command value set by 4 is applied to the constant-current welding power supply device 13
Therefore, the constant current welding power supply device 13 outputs 90 ° across the left and right sides of the backward center CR in the traveling direction of the arc circle R for each revolution of the tungsten electrode 2 of the electrode rotary TIG welding torch 12. With respect to the predetermined angle range θp, a welding current higher than that in the other angle ranges is passed. That is, the constant current welding power source device 13 is the electrode rotating TIG.
For example, 100 A is applied to the tungsten electrode 2 of the welding torch 12.
The low current and the high current of 150 A flow alternating pulsed welding currents. In this way, the pulsed welding current is applied to the tungsten electrode 2 of the electrode rotating TIG welding torch 12.
By flowing the water to the right side, an appropriate bead surface shape is formed as shown by the solid line in FIG. 6 and deep penetration can be formed on the lower plate 1a side. In the above embodiment, the angle range θp of the output signal output by the current switching timing circuit 33 based on the position detection signal of the rotational position detector 11 is set to 90 °, but the center of the arc in the traveling direction of the rotating circle R is the rear center. It goes without saying that an angular range θp of 5 ° or more and 60 ° or less extending over the left and right sides of CR may be used.

FIG. 7 is an explanatory view showing a groove copying method of a third embodiment according to the present invention. In this embodiment, as indicated by the slanting lines of the arc R of the arc shown in FIG. 7, the current switching timing circuit 33 causes the electrode rotary TIG welding torch based on the position detection signal of the rotary position detector 11 during the welding described above. 12
The tungsten electrode 2 outputs a predetermined output signal to the switch 35 every other unit for each rotation unit. On the other hand, the current setting device 34 outputs to the switch 35 a command of a high current value set so that the constant current welding power supply device 13 outputs a high output current. Therefore, when the switching device 35 receives the output signal from the current switching timing circuit 33, it outputs the high current command value set by the current setting device 34 to the constant current welding power supply device 13. Therefore, the constant current welding power supply device 13 Is the electrode rotation TI
A high welding current is passed every other one rotation unit of the tungsten electrode 2 of the G welding torch 12. That is, the constant current welding power supply device 13 supplies the tungsten electrode 2 of the electrode rotary TIG welding torch 12 with a low current of, for example, 50 to 60 A and a low current of 120 A.
A high current of up to 140 A causes a welding current to flow in a pulse shape alternately in one rotation unit. By thus applying a pulsed welding current to the tungsten electrode 2 of the electrode rotary TIG welding torch 12, a proper bead surface shape is formed and deep penetration can be formed on the lower plate 1a side.

In this embodiment, the scanning control of the tungsten electrode 2 of the electrode rotating TIG welding torch 12 is performed when a high current of 150 A is applied to the tungsten electrode 2.
The output signal from the current switching timing circuit 33 is output to the timing circuit 26, and the timing circuit 26 is configured to receive the output signal from the current switching timing circuit 33. In this way, the copying control of the tungsten electrode 2 is performed when the welding current is high because, generally, when the current is low, the arc fluctuates and it is difficult to perform accurate control. Current is 100
When the high current is 150 A at A, even if the copying control is performed when the current is low, the arc does not fluctuate and accurate control is performed.

Although the electrode rotary TIG welding method and the electrode rotary TIG torch 12 of the electrode rotary TIG welding apparatus have been described in the above embodiments, the present invention is plasma welding using a tungsten electrode or a copper electrode other than a tungsten electrode, a carbon electrode. Needless to say, the present invention can be applied to other welding methods and welding devices that use non-consumable electrodes called electrodes.

[0033]

As described above, according to the present invention, the tip of the non-consumable electrode provided on the welding torch is circularly moved, and the arc generated in the non-consumable electrode is rotated at a high speed in one direction to weld the overlapping portion of the thin plates. When lap welding is performed along the line, the arc voltage is detected, and from the arc voltage, two points on the left and right of the arc line in the welding line of the lap portion of the thin plate are used as a reference with respect to the center in the forward direction. The difference between the integrated values of the arc voltage waveforms at the electrode rotational position in one predetermined angle range is compared with a predetermined threshold value, and the welding torch is moved in a direction orthogonal to the welding line so that the difference becomes zero. The welding torch is controlled to a proper position with respect to the welding line of the overlapped portion of the thin plates, and for each revolution of the welding torch, a predetermined angle across the left and right of the rear center of the traveling direction of the arc rotation circle is used as a reference. With respect to the enclosure, since a higher welding current is made to flow than in the case of other angle ranges, it is possible to automatically follow the torch at the proper position with respect to the welding line of the lap weld joint of the thin plate, There is an effect that the bead surface shape and the penetration of the base material, particularly the stabilization of the penetration on the lower plate side can be secured and the bead surface shape of the lap weld can be appropriately maintained.

Further, a circular motion is applied to the tip of the non-consumable electrode provided on the welding torch, and a low current and a high current are alternately passed through the welding torch in units of rotation of the electrode, so that the arc generated on the non-consumable electrode is made to flow. The arc voltage is detected when a low current or a high current is applied to the welding torch during welding in which lap welding is performed along the welding line of the lap portion of the thin plate while rotating at high speed in the direction. Of the arc voltage, the respective integrated values of the arc voltage waveforms at the electrode rotation positions within the two predetermined angle ranges on the left and right of the forward center of the traveling direction of the rotating circle of the arc parallel to the welding line of the overlapping portion of the thin plates. Difference is compared with a predetermined threshold value, and the welding torch is controlled to move in a direction orthogonal to the welding line so that the difference becomes zero, and the welding torch is properly positioned with respect to the welding line of the overlapping portion of the thin plates. To control Even with this, the torch can be made to automatically follow the welding line of the lap weld joint part of the thin plate, and the bead surface shape and the penetration of the base metal, especially the penetration of the lower plate This has the effect of ensuring stabilization and maintaining the bead surface shape of the lap weld appropriately.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire groove-tracing control device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an electrode rotary TIG torch of the electrode rotary TIG welding device.

FIG. 3 is a schematic diagram showing a scanning signal detecting method of the groove line scanning method.

FIG. 4 is an explanatory diagram showing a difference in bead shape depending on an aiming position.

FIG. 5 is an explanatory diagram showing a groove line tracing method according to a second embodiment of the present invention.

FIG. 6 is an explanatory view showing a bead shape formed by the groove line copying method of the embodiment.

FIG. 7 is an explanatory diagram showing a groove line tracing method according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Tungsten electrode (non-consumable electrode) 11 Rotation position detector 12 Electrode rotation TIG torch 14 Arc voltage detector 22 Lateral movement mechanism controller (drive control part) 23 Torch lateral movement mechanism 24 Lateral movement motor 24 26 Timing Circuit 27a Integrator 27b Integrator 28 First comparator 29 Torch position aiming position setting device 30 Second comparator 31 Welding line copying control circuit 32 Copying driving control circuit (driving control section) 33 Current switching timing circuit 34 Current setting device 35 Current setting device

Claims (3)

[Claims] 1. A lap welding is performed along a welding line of a lap portion of a thin plate while applying a circular motion to a tip of the non-consumable electrode provided on a welding torch and rotating an arc generated at the non-consumable electrode at a high speed in one direction. During welding, the arc voltage is detected, and of the arc voltage, 5 ° or more and 180 ° or less on the left and right of the forward center of the traveling direction of the arc of rotation of the arc parallel to the welding line of the thin plate overlap The difference between the respective integral values of the arc voltage waveforms at the rotational positions of the electrodes in the two predetermined angle ranges is compared with a predetermined threshold value, and the welding torch is moved in the direction orthogonal to the welding line so that the difference becomes zero. Movement control is performed to control the welding torch at an appropriate position with respect to the welding line of the overlapped portion of the thin plates, and further, for each revolution of the welding torch, 5 ° straddling the rear center of the traveling direction of the arc rotation circle as a reference. Above 160 ° Given the angle range, groove copying method in the electrode rotating non-consumable electrode arc welding, characterized in that it has to flow to the high welding current than in the other angle range. 2. A circular motion is applied to the tip of the non-consumable electrode provided on the welding torch, and a low current and a high current are alternately applied to the welding torch in units of rotation of the electrode to generate an arc generated on the non-consumable electrode. The arc voltage is detected when a low current or a high current is applied to the welding torch during welding in which lap welding is performed along the welding line of the lap portion of the thin plate while rotating at high speed in the direction. Of the arc voltage, the arc at the electrode rotation position within the two predetermined angle ranges of 5 ° or more and 180 ° or less on the left and right of the forward center of the traveling direction of the rotating circle of the arc parallel to the welding line of the overlapping portion of the thin plates. Compare the difference of each integrated value of the voltage waveform with a predetermined threshold,
An electrode characterized in that the welding torch is controlled to move in a direction orthogonal to the welding line so that the difference becomes zero, and the welding torch is controlled to an appropriate position with respect to the welding line of the overlapping portion of the thin plates. A groove copying method in rotary non-consumable electrode arc welding. 3. A groove copying control device in electrode rotating non-consumable electrode arc welding, comprising a non-consumable electrode rotating arc welding device for carrying out the electrode rotating non-consumable electrode arc welding method, wherein a predetermined welding current is output. And a welding power source that outputs a welding current according to the command, an arc voltage detector that detects the arc voltage between the electrode and the workpiece of the welding torch that is welded by the power source supplied from the welding power source, and the rotation angle of the electrode. A rotary position detector that detects a position, an integrator to which a detection signal of the arc voltage detector is input, and a detection signal of the arc voltage detector that is preset based on the position detection signal of the rotary position detector A timing circuit that outputs a signal that operates an integrator for two detection signals in a predetermined angle range, and two detection signals in a predetermined angle range that are respectively output from the integrator From the first comparator, the first comparator that obtains the difference between the integrated values, the torch target position setting device that outputs the reference value that sets the welding torch at a predetermined position near the welding line in the direction orthogonal to the welding line, and the first comparator A second comparator for obtaining the difference between the output integrated value difference and the reference value of the torch aiming position setter;
A drive control unit that drives and controls the welding torch in a direction orthogonal to the welding line based on the difference between the integrated value output from the second comparator and the reference value so that the difference becomes zero; Based on the position detection signal of the position detector, output a predetermined output signal only for a predetermined angle range set in advance for each rotation of the electrode, or output a predetermined output signal every other rotation of the electrode for each rotation of the electrode. Current switching timing circuit for
The current setting device that sets a high current value so that the welding power supply device outputs a high output current, and the high current command value set by the current setting device when the output signal from the output current switching timing circuit is received. A groove copying control device in electrode rotating non-consumable electrode arc welding, comprising: a switching device for outputting to the welding power source device.