JP3183038B2 - Groove profiling method and groove profiling control device in electrode rotating non-consumable electrode arc welding - Google Patents

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, and relates to non-consumable TIG welding, plasma welding, and the like that do not use a filler material that forms beads by melting a base material on an upper plate and a lower plate. In the electrode arc welding method, the bead surface shape is good and a wide and shallow penetration weld is formed, while automatically detecting the welding line formed by the overlap of thin plates and the torch at the appropriate position with respect to the welding line. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a groove profiling method and a groove profiling control device in electrode rotating non-consumable electrode arc welding in which erroneous operation of groove profiling due to tacking or disturbance noise is prevented.

[0002]

2. Description of the Related Art Conventionally, a torch follows a welding line in lap welding of thin plates by manual operation of an operator, or, although expensive, a contact type sensor is used for the detection, or a complicated image is formed by an optical type sensor. Processing method was adopted. In order to automate welding, the latter two methods are required, but in any case, in addition to the torch, it is necessary to provide a unique device called a sensor near the torch. Due to dimensional restrictions, a certain gap was generated between the position and the position. Therefore, it is necessary to control the torch position by giving a time difference corresponding to the interval, and only complicated control can be performed with a limited accuracy. Japanese Patent Publication No. 61-17591 discloses an arc sensor groove tracing method using a welding arc itself as a sensor without using a separate sensor and having excellent accuracy in welding line profiling. This arc sensor groove profiling method changes the arc characteristics due to torch swing in the groove,
After time integration with the half cycle of the left and right swings based on the center of the swing width, and then comparing them, so that both become equal,
That is, by controlling the movement of the torch swing center so that the difference between the two becomes zero, the groove line following is achieved. However, there is a drawback that the method cannot be applied to a joint in which one groove does not exist, such as a weld line of a lap welded part of a thin plate. Also, in the method disclosed in Japanese Patent Publication No. 1-4875 (JP-A-57-91877), a groove copying method using electrode rotation is disclosed. Could only be applied when there was.

[0003]

In order to automate the welding, a groove detecting sensor is used to automatically control the torch position in response to a two-dimensional displacement of a welding line that changes every moment during welding. In addition, a torch position movement adjusting mechanism using a detection sensor is required. Conventionally, the torch follows the welding line in the lap welding of thin plates, either by the operation of the welding operator, or it is expensive for automation of welding, but using a contact sensor for detection, or complicated by an optical sensor It is necessary to adopt a special image processing method, but in any case, in addition to the torch, it is necessary to provide a unique device called another sensor near the torch, and the dimensional difference between the detection position and the control target position is required. There is a certain interval due to restrictions, and it is necessary to control the torch position by giving a time difference according to the interval, and there is a problem that only a control with a limited accuracy can be performed for a complicated case. In addition, in the lap welding of thin plates, good or required in non-consumable electrode arc welding methods such as TIG welding and plasma welding in which a bead is formed by melting a base material on an upper plate and a lower plate side without using a filler metal. In order to obtain the desired bead surface shape, the target position of the torch must always be maintained at an appropriate position.

[0004] The present invention provides a welding line excellent in accuracy without using a separate sensor for one of the grooves, ie, a joint having no step, such as a welding line for a lap welding portion of a thin plate. Even if automatic copying is performed, and even if there is a portion on the weld line that is a source of noise for a copying signal such as tacking or an oxide that disturbs the arc, malfunction of groove copying due to tacking or disturbance noise is prevented. An object of the present invention is to provide a groove profiling method and a groove profiling control device in electrode rotating non-consumable electrode arc welding that can stabilize tracing and appropriately maintain the bead surface shape of a lap weld portion of a thin plate. It is.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a groove tracking method in electrode rotating non-consumable electrode arc welding, in which a circular motion is applied to a tip of a non-consumable electrode provided on a welding torch, and the non-consumable electrode is provided with a circular motion. The arc voltage is detected during welding, which performs lap welding along the welding line of the overlapping portion of the thin plate while rotating the generated arc at a high speed in one direction, and among the arc voltage, the welding voltage of the overlapping portion of the thin plate is detected. The welding torch determines the difference between the integral values of the arc voltage waveforms at the rotation positions of the electrodes in two predetermined angle ranges from 5 ° to 180 ° on the left and right sides of the forward center of the traveling direction of the parallel arc rotating circle. A difference is calculated by comparing with a reference value when set to an appropriate position of the welding line, and the movement of the welding torch is controlled in a direction orthogonal to the welding line so that the difference becomes zero. In the section with the difference The average value of the, to compare the average value and a reference value to stop the copying control of the welding torch, when the difference between the average value and the reference value is a predetermined value or more, stop the movement control of the welding torch, When the difference between the average value and the reference value is equal to or less than a predetermined value, the movement control of the welding torch is continued,
The welding torch is controlled at an appropriate position with respect to the welding line at the overlapping portion of the thin plates.

A groove tracking control apparatus for non-consumable electrode arc welding of a rotary electrode according to the present invention detects an arc voltage between an electrode of a welding torch and a workpiece to be welded by a non-consumable electrode arc welding method of a rotary electrode type. An arc voltage detector, a rotation position detector for detecting a rotation angle position of the electrode,
An integrator to which a detection signal of an arc voltage detector is input; and an integrator for detecting detection signals in two predetermined angle ranges set in advance based on a position detection signal of a rotation position detector among detection signals of the arc voltage detector. A timing circuit for outputting a signal for operating the first and second comparators, a first comparator for obtaining a difference between integrated values of two detection signals output from the integrator in a predetermined angle range, and a welding torch set at an appropriate position on a welding line. A torch target position setting device that outputs a reference value when the torch is set, and a second comparison that calculates a difference between a difference between an integrated value output from the first comparator and a reference value output from the torch target position setting device. A welding line tracing control circuit for calculating and outputting a signal that makes the difference zero based on a signal of the difference between the integral value and the reference value output from the second comparator; Based on the signal from the scanning control circuit A lateral movement mechanism controller that drives and controls the welding torch in a direction orthogonal to the welding line, a difference signal average value circuit that calculates and outputs an average value in a certain section of the difference signal from the second comparator, A scanning control stop setting device that outputs a reference value for stopping the welding torch scanning control, and a third comparator that calculates a difference between the average value output from the difference signal average value circuit and the reference value of the scanning control stop setting device. And when the difference between the average value and the reference value output from the third comparator is equal to or greater than a predetermined value, the output of the signal from the welding line following control circuit to the lateral movement mechanism controller is stopped, and the average value A scanning control on / off switch for continuing to output a signal from the welding line scanning control circuit to the lateral movement mechanism controller when the difference between the reference value and the reference value is equal to or less than a predetermined value.

[0007]

FIG. 1 is a block diagram showing an entire groove tracking control apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view showing an electrode rotating TIG torch of an electrode rotating TIG welding apparatus, and FIG. FIG. 4 is a schematic diagram showing a copying signal detection method of the leading copying method, and FIG. 4 is an explanatory diagram showing a difference in bead shape depending on a target position. In the figure, reference numeral 1 denotes a base material in which an upper plate 1b is superimposed on a lower plate 1a which is a material to be welded, 2 denotes a tungsten electrode which is a non-consumable electrode positioned on a groove of the base material 1, and 3 denotes a rotary drive motor. , 3
a is a shaft of the rotary drive motor 3, 4 is a drive gear attached to the shaft 3a and is provided with high-speed rotation by the rotary drive motor 3, 5 is a driven gear provided with high-speed rotation by the drive gear 4, and 6 is a tungsten electrode. The cylindrical electrode holding member 6b held by the collet chuck 6a provided at the tip is a gas cup provided below the electrode holding member 7 and surrounding the tungsten electrode 2.

An upper self-aligning bearing 7 rotatably supports the upper part of the electrode holding member 6, and an upper self-aligning bearing 8 is held eccentrically by a fixed amount from the center of rotation of the ring. Is an eccentric ring that holds a predetermined amount of eccentricity from the rotation center of the driven gear 5, and forms an eccentric ring member with the upper self-aligning bearing 7. 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 part of the electrode holding member 6. 11 is a rotation angle position of the rotation drive motor 3;
That is, it is a rotational position detector such as an encoder that detects the rotational angle position of the tip of the tungsten electrode 2. In addition, a welding voltage is applied between the tungsten electrode 2 and the base material 1 which are held by the electrode holding member 6 and located on the axis thereof by a constant current welding power supply device described later, and an arc is generated.
Reference numeral 12 denotes an electrode rotation TIG torch including the tungsten electrode 2 and the rotation position detector 11.

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

Reference numeral 17 denotes an arc voltage reference setting device for setting a reference arc voltage between the tungsten electrode 2 and the base material 1, and 18 denotes 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 19 for performing a comparison operation, 19 is an elevating motor controller for controlling the rotation of an elevating motor 21 of a torch elevating mechanism 20 based on the output of the differential amplifier 18, 22 is a lateral motor 24 of a torch lateral moving mechanism 23
Is a lateral movement mechanism controller that controls the rotation of the torch, and 25 is a welding carriage that supports the torch elevating mechanism 20 and the torch lateral movement mechanism 23 and travels on the base material 1.

Reference numeral 26 denotes a timing circuit for outputting a signal for operating an integrator with respect to two detection signals within a predetermined angle range set in advance based on the position detection signal of the rotational position detector 11, and 27a and 27b denote arc voltage detectors 14. The arc voltage detection signal is input and the timing circuit 26
The integrator 28 also receives a signal from the integrator 27.
A first comparator for calculating a difference between the integrated values output from the output terminals 27b;
29 is a torch aiming position setter that outputs a reference value when the electrode rotating TIG torch 12 is set at an appropriate position near the welding line in a direction orthogonal to the welding line, and 30 is an integral output from the first comparator 28. A second comparator 31 for calculating a difference between the value difference and the reference value output from the torch aiming position setting device 29, based on the difference between the integrated value output from the second comparator 30 and the reference value. This is a welding line scanning control circuit that outputs a control signal to the lateral movement mechanism controller 22 so that the difference becomes zero.

Reference numeral 32 denotes a difference signal averaging circuit for calculating and outputting an average value for each section of the difference signal from the second comparator 30, that is, at predetermined time intervals, and 33 denotes an electrode rotation TIG torch 1
A tracing control stop setting unit 34 for outputting a reference value for stopping the tracing control 2 is for calculating and outputting a difference between the average value output from the difference signal average value circuit 32 and the reference value of the tracing control stop setting unit 33. When the difference between the average value and the reference value output from the third comparator 34 is equal to or greater than a predetermined value, the third comparator 35 receives a signal from the welding line tracing control circuit 31 and sends the lateral movement mechanism controller 22.
To stop the output of the signal to the lateral movement mechanism controller 22 from the welding line scanning control circuit 31 when the difference between the average value and the reference value is equal to or less than a predetermined value. An off switch.

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 rotation 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. Since the eccentric ring 8 rotatably holds the upper self-aligning bearing 7 that rotatably supports the upper part of the electrode holding member 6 at an eccentric position at a fixed distance from the ring rotation center, the eccentric ring 8 is rotatable.
Is rotated around the rotation axis thereof as the eccentric ring 8 rotates. Further, the lower part of the electrode holding member 6 is coaxially attached to the center of rotation of the eccentric ring 8 and is also held by the lower self-aligning bearing 10 fixed around its periphery. By the action of the ring 8, the tip of the tungsten electrode 2 extending downward from the lower portion of the electrode holding member 6 performs a slidable circular motion with the lower self-aligning bearing 10 as a fulcrum of the center of rotation.

When the tip of the tungsten electrode 2 is making a circular motion, the lower portion of the electrode holding member 6 holding the base of the tungsten electrode 2 is rotatably supported by a lower self-aligning bearing 10 and has a rotation center. And does not rotate itself, so that 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 universal bearing having the same function as a spherical plain bearing, a unit ball bearing, or the like.

Next, the operation of the electrode rotating TIG welding apparatus will be described. For example, when lap welding of a stainless steel thin plate having a thickness of 2 mm, the electrode rotation diameter of the tungsten electrode 2 which is a non-consumable electrode is set to 2.5 mm, the electrode rotation frequency is set to 3 to 5 Hz by the rotation drive motor 3, and constant current welding is performed. With a welding current of 140 A by the device 13, a circular motion is applied to the tip of the tungsten electrode 2 to rotate the arc generated at the tungsten electrode 2 at a high speed, and at a welding speed of 25 to 30 cm / min along the welding line of the base material 1. Perform lap welding.
At this time, the torch inclination angle is maintained 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 molten. However, while the arc was being generated, the tip of the tungsten electrode 2 was mechanically formed into a substantially circular shape. Since the welding is performed by moving, the welding arc is applied to the welded portion of the base material 1 by the tungsten electrode 2.
With the rotation of the tip of the arc, the welded part moves in a circular shape, and the molten part immediately below the arc moves with a certain rotation diameter, and the heat input to the welded part of the arc is dispersed in a certain diameter Becomes
As a result, a wide and shallow penetration weld can be efficiently formed at high speed.

In the TIG arc, the effect of the rotation of the tungsten electrode 2 is determined by whether or not the arc can move through the molten portion with the rotation. In the case of the TIG arc, the electrode rotation frequency is about 20 Hz. It is a 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 a significant decrease in the melting efficiency of the base material due to the heat input dispersion. In the case of a TIG arc in which the welding current used in lap welding of thin plates is more than tens of A to more than two hundred and tens of A, the appropriate range is about 1 to 4 mm as the rotation diameter. The appropriate range of the rotation diameter depends on the value of the welding current to be used.

Next, a method for following a groove line during welding will be described with reference to FIGS. 1, 3 and 4. FIG. First, the principle of the groove line copying method will be described. Electrode rotation TIG
The welding is performed along the welding line of the base material 1 including the lower plate 1a and the upper plate 1b to which the tungsten electrode 2 provided on the torch 12 is overlap-welded. Then, as shown in FIG. 3A, the tip of the tungsten electrode 2, that is, the arc is located at the rear center C.P. From point A, which is the R position, to 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 gradually increases as shown in FIG. 3B. However, at the point B, the increase of the arc voltage becomes almost maximum. Then, from the point B, the front center C. in the traveling direction of the arc rotation circle R. The arc voltage gradually decreases as it comes to the point C, which is the F position, and when the arc rotates to the point D on the upper plate 1b side from the point C, the arc voltage is detected at the rotational position on the upper plate 1b side. The arc voltage detected by the detector 14 gradually decreases, and at the point D, the decrease in the arc voltage becomes almost maximum. Thereafter, the arc voltage increases from point D to point A.

FIG. 3B shows the change of the arc voltage with reference to the reference voltage.
SR is the forward center C.D. in the traveling direction of the rotating circle of the arc in FIG. 0 ° to 90 ° left and right with respect to F (R area)
And 270 ° to 360 ° (L region) in two predetermined angle ranges θ1 and θ2. Therefore, when the arc voltages on the lower plate 1a side and the upper plate 1b side of the rotating tungsten electrode 2 are respectively detected and the integrated values of the two voltages are compared, the center of the rotating circle R at the tip of the tungsten electrode 2 becomes the base metal. It can be seen whether the welding line 1 is located at an appropriate position. Therefore, when the arc voltage between the lower plate 1a and the upper plate 1b is detected, the integrated value of the detected voltages is compared to determine the difference, and the difference is determined when the welding torch is set to the proper position of the welding line. By comparing with the reference value, it can be determined whether or not the center of the rotating circle R at the tip of the tungsten electrode 2 is located at an appropriate position of the welding line of the base material 1.

Next, the groove line copying method will be described.
When welding is performed along the welding line of the base material 1 composed of the lower plate 1a and the upper plate 1b on which the tungsten electrode 2 provided on the electrode rotating TIG torch 12 is overlap-welded, the arc voltage detector 14 detects the tungsten. The arc voltage that is changed by the rotation of the tip of the electrode 2 is detected, and the integrators 27a and 27
b. On the other hand, the rotation position detector 11 detects the rotation position of the rotating tungsten electrode 2 and outputs a position detection signal to the timing circuit 26. And
In the timing circuit 26, based on the position detection signal of the rotation position detector 11, the front center C.I. For example, 0 on the upper plate 1b side set in advance with reference to F
The angle range θ1 of 90 ° which is 90 ° to 90 ° and the angle range θ2 of 90 ° which is, for example, 270 ° to 360 ° on the lower plate 1a side
, The integrators 27a and 27b integrate the arc voltage.

The integrated values obtained by integrating the arc voltages by the integrators 27a and 27b are input to a first comparator 28. The reason why the integration is performed by the integrators 27a and 27b 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
ΔS of the integrated value SR by
Output to the comparator 30. The second comparator 30 compares the difference between the integral values obtained by the first comparator 28 and the reference value output from the torch aiming position setting device 29, and outputs a signal of the difference to the welding line scanning control circuit 31. The welding line scanning control circuit 31 outputs a lateral movement command signal to the lateral movement mechanism controller 22 such 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 control the movement of the electrode rotation TIG torch 12 in a direction orthogonal to the welding line, thereby controlling the welding line at the overlapping portion of the thin plate. The electrode rotation TIG torch 12 is controlled so that the electrode rotation TIG torch 12 comes to an appropriate position, that is, the center of the rotating circle at the tip of the tungsten electrode 2 is located at an appropriate position on the welding line.

When the welding line of the base material 1 composed of the lower plate 1a and the upper plate 1b to be overlap-welded as shown in FIG. In the method of controlling to the position, since the position accuracy and followability of the electrode rotating TIG torch 12 are good,
In some places, the bead is always moved to the upper plate 1b side, so that the bead is temporarily attached to the upper plate 1b as shown by the broken line in FIG.
It appears to meander to the b side. Further, when the electrode rotating TIG torch 12 comes to the place where the tack T is present, the difference signal S output from the second comparator 30 to the welding line scanning control circuit 31 changes greatly as shown in FIG. Such a change in the difference signal is also caused by disturbance noise.

Therefore, when performing groove profiling in a case where the welding line of the base material 1 is tacked, the groove tracing method is performed as follows. First, as described above, the difference between the integral value obtained by the first comparator 28 output from the second comparator 30 and the torch target position setting device 29 Is output to the welding line profiling control circuit 31 and the welding line profiling control circuit 3
At 1, a lateral movement command signal is output to the lateral movement mechanism controller 22 so that the difference obtained by the second comparator 30 becomes zero, and the lateral movement mechanism controller 22 rotates the lateral movement motor 24 to rotate the torch. The electrode rotating TIG torch 12 is controlled by driving the moving mechanism 23 to move the electrode rotating TIG torch 12 in a direction orthogonal to the welding line so that the electrode rotating TIG torch 12 comes to an appropriate position of the welding line at the overlapping portion of the thin plates. Control.

Next, a difference signal is applied to the welding line of the base material 1 where the tacking is present during the groove line tracing control which is performed for the welding line of the base material 1 where the tacking is not present. The average value circuit 32 calculates an average value for each section of the difference signal S output from the second comparator 30 and outputs the average value to the third comparator 34. In the third comparator 34, the difference signal average value circuit 32
Is calculated and the difference between the reference value of the scanning control stop setting unit 33 is obtained and output to the scanning control ON / OFF switching unit 35. When the difference between the reference value for stopping the scanning control of the welding torch output from the third comparator 34 and the average value of the difference signal averaging circuit 32 is equal to or greater than a predetermined value, the control on / off switch 35 sets the welding line. The output of the signal from the scanning control circuit 31 to the lateral movement mechanism controller 22 is stopped to stop the movement control of the welding torch. If the difference between the average value and the reference value is equal to or less than a predetermined value, the welding line scanning control circuit 31
And the movement control of the welding torch is continued. By doing so, the welding torch is controlled to an appropriate position with respect to the welding line at the overlap portion of the thin plate, and the meandering of the bead is considerably reduced.

The torch aiming position setting device 29 is arranged so that the tip of the tungsten electrode 2, that is, the center of the rotating circle R of the arc is located at the aiming position A shown in FIG. In such a case, the reference value may be set to, for example, 0 V. When the center of the rotating circle R of the arc is located at the target position B shown in FIG. For example, when the target position is set to 0.7 V and 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 always exists at the target position properly. As described above, the arc voltage during welding is detected, the arc voltage is signal-processed, and control is performed so that the center of the arc rotation circle R is located at the target position so that the electrode rotation TIG torch 12 is automatically followed. 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 if it changes by 0.2 to 0.3 mm, the bead shape may be deteriorated. In addition, the target position changes depending on the plate thickness, and FIG.
The bead shape changes as shown in (b) and (c). The torch angle is preferably within approximately ± 10 ° of vertical, and 0.5 to
In the case of a thin plate having a thickness of about 2.5 mm, it is preferable that the target position of the welding line profile is about 0.5 to 0.8 mm closer to the upper plate than the end of the upper plate. Further, the electrode rotating TIG torch 12 needs to adjust the torch elevating operation in order to prevent a short circuit of the tungsten electrode 2 to the base material 1. Electrode rotation TIG
The adjustment of the elevating operation during welding of the torch 12 is performed by calculating the deviation between the arc voltage detection signal from the arc voltage detector 14 and the reference arc voltage from the arc voltage reference setter 17 by the differential amplifier 16, and this deviation is always zero. The lifting motor controller 19 controls the rotation of the lifting motor 21 so that the electrode rotating TIG torch 12 is raised and lowered.

In the above embodiment, the target of the arc voltage integrated by the integrators 27a and 27b is 0 ° to 90 ° on the upper plate 1b side.
The angle range is 90 °, that is, 90 °.
The angle range θ2 is 90 ° which is 70 ° to 360 °, but the angle range θ1 is 175 ° which is 5 ° to 180 ° on the upper plate 1b side, and 180 ° to 355 ° on the lower plate 1a side.
Needless to say, even if the angle range θ2 of 175 ° is set, the center of the rotating circle R of the arc can be controlled to be at an appropriate position with respect to the welding line. In the above embodiment, two integrators 27a and 27b are used. However, one integrator integrates two detection signals within a predetermined angle range, and outputs two integrated values to the first comparator 28. Well,
In this case, a single integrator is sufficient if the detection signal in one predetermined angle range is integrated, its value is transferred to another, reset at high speed, and the detection signal in the other predetermined angle range is integrated. In the above embodiment, the electrode rotation T
IG welding method and electrode rotation T
Although the IG torch 12 has been described, it goes without saying that the present invention can also be applied to other welding methods and welding devices using non-consumable electrodes such as plasma welding using a tungsten electrode or a copper electrode other than a tungsten electrode and a carbon electrode. Nor.

[0028]

As described above, the present invention applies a circular motion to the tip of the non-consumable electrode provided on the welding torch, and rotates the arc generated on the non-consumable electrode in one direction at a high speed to weld the overlapping portions of thin plates. When the lap welding is performed along the line, the arc voltage is detected, and the arc voltage is detected based on the center of the welding line at the overlapped portion of the thin plate in the forward direction of the rotating circle of the arc as a reference. The difference between the respective integral values of the arc voltage waveforms at the rotation positions of the electrode in two predetermined angle ranges of not less than 180 ° and not more than 180 ° is compared with a reference value when the welding torch is set at an appropriate position of the welding line, and the difference is obtained. Calculate and control the movement of the welding torch in a direction perpendicular to the welding line so that the difference becomes zero, find an average value in the section with the difference during the control, and follow the average value and the welding torch. Stop control When the difference between the average value and the reference value is equal to or more than a predetermined value, the movement control of the welding torch is stopped. When the difference between the average value and the reference value is equal to or less than a predetermined value, the welding torch is stopped. The welding torch is controlled to the appropriate position with respect to the welding line at the overlapped portion of the thin plate, so that the automatic welding of the welding line at the welded joint portion of the thin plate can be performed. Even if a shallow penetration weld can be formed efficiently at high speed, and even if there is a portion on the weld line that is a source of noise of a copying signal such as an oxide that disturbs the arc or a temporary attachment, The welding torch is controlled to the proper position with respect to the welding line at the overlapped part of the thin plate, to prevent the bead from meandering due to noise or disturbance noise, etc. Has the effect of being able to maintain

[Brief description of the drawings]

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

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

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

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

FIG. 5 is an explanatory diagram showing a change in a copying signal when a temporary welding is performed on a welding line of a base material;

FIG. 6 is an explanatory diagram showing a bead shape when welding is performed on a welding line of a base material on which temporary attachment is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Tungsten electrode (non-consumable electrode) 11 Rotational position detector 12 Electrode rotation TIG torch 14 Arc voltage detector 22 Lateral movement mechanism controller 23 Torch lateral movement mechanism 24 Lateral movement motor 24 26 Timing circuit 27a Integrator 27b Integrator 28 First comparator 29 Torch target position setting device 30 Second comparator 31 Welding line scanning control circuit 32 Difference signal average value circuit 33 Scanning control stop setting device 34 Third comparator 35 Scanning control on / off switching device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-26946 (JP, A) JP-A-63-224871 (JP, A) JP-A-52-94844 (JP, A) JP-A-60-1985 127082 (JP, A) JP-A-59-215279 (JP, A) JP-A-61-273263 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/127 B23K 9 / 022

Claims (2)

(57) [Claims] 1. A circular motion is applied to a tip of a non-consumable electrode provided on a welding torch, and an arc generated on the non-consumable electrode is rotated at a high speed in one direction, and lap welding is performed along a welding line at a lap portion of a thin plate. During welding, the arc voltage is detected, and the arc voltage is 5 ° or more and 180 ° or less on the left and right with respect to 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 plate. 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 determined when the welding torch is set at an appropriate position on the welding line.
Calculate the difference by comparing with a reference value, and control the movement of the welding torch in a direction orthogonal to the welding line so that the difference becomes zero,
During the control, an average value in the section having the difference is obtained, and the average value is compared with a reference value for stopping the copying control of the welding torch, and when a difference between the average value and the reference value is equal to or more than a predetermined value. Stops the movement control of the welding torch, and when the difference between the average value and the reference value is equal to or less than a predetermined value, continues the movement control of the welding torch, and positions the welding torch at an appropriate position with respect to the welding line of the overlapping portion of the thin plate. A method for following a groove in non-consumable electrode arc welding using a rotating electrode, characterized in that: 2. An arc voltage detector for detecting an arc voltage between an electrode of a welding torch and a work to be welded by an electrode rotating non-consumable electrode arc welding method, a rotation position detector for detecting a rotation angle position of the electrode, An integrator to which a detection signal of an arc voltage detector is input; and an integrator for detecting detection signals in two predetermined angle ranges set in advance based on a position detection signal of a rotation position detector among detection signals of the arc voltage detector. soluble and timing circuit for outputting a signal for operating a first comparator for obtaining a difference of the integral values of the detection signals of the two predetermined angular range that is output from the integrator, the welding torch
A torch target position setting device that outputs a reference value when the tangent line is set to an appropriate position, and a difference between an integrated value output from the first comparator and a reference value output from the torch target position setting device. And a welding line trace that calculates and outputs a signal that makes the difference zero based on a signal of the difference between the integral value and the reference value output from the second comparator. A control circuit, a lateral movement mechanism controller that drives and controls the welding torch in a direction orthogonal to the welding line based on a signal from the welding line scanning control circuit, and a section having a difference signal from the second comparator. A difference signal average value circuit that calculates and outputs an average value, a scanning control stop setting device that outputs a reference value for stopping the welding torch scanning control, and an average value and a scanning control stop setting output from the difference signal average value circuit A third comparator for determining a difference from a reference value of the detector, and a third ratio When the difference between the average value and the reference value output from the welding machine is equal to or greater than a predetermined value, the output of the signal from the welding line scanning control circuit to the lateral movement mechanism controller is stopped, and the difference between the average value and the reference value is determined. An electrode rotating type non-consumable electrode arc, comprising: a scanning control on / off switching device for continuing to output a signal from the welding line scanning control circuit to the lateral movement mechanism controller when is smaller than a predetermined value. Groove tracking controller for welding.