JP2570015B2 - Method and apparatus for determining welding stability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for judging whether or not stable welding is performed when welding is performed on a welded joint by a high-speed rotating arc welding method. Things.

[0002]

2. Description of the Related Art When welding is performed on a weld joint by a high-speed rotating arc welding method, a groove tracking control method using an arc sensor is usually employed for automatically following a welding line. Here, the high-speed rotating arc welding method is a method in which the tip of an electrode wire is eccentric, and welding is performed while rotating the arc at a high speed by mechanically rotating an electrode nozzle of a welding torch. Such a groove following control method is known in Japanese Patent Application Laid-Open No. 62-248571 and the like.
, The arc voltage waveform and the arc rotation position (Cf, R, Cr, L) are detected, and the same phase angle φ (5 ° ≦ φ ≦ 9
0 °), the arc voltage waveform is integrated (SL, SR
), The torch position deviation in the groove width direction (X-axis) is corrected so that the difference (SL-SR) becomes zero. In the torch height direction (Y axis), control is performed so that the integral value of the welding current waveform is constant for each rotation of the arc.

[0003]

In the case of performing welding by a high-speed rotating arc welding method, a groove tracking control method using an arc sensor is employed to perform stable welding. Sometimes became unstable. For example, fluctuations in the wire feed speed due to the wire feed path being clogged by dust or wire debris, and the use of the welding tip for a long time causes the welding tip to be consumed and the wire passage hole to become large. Variations in the current-carrying point of the welding tip, insufficient gas flow rate, poor shielding gas due to gas leakage, and poor welding conditions such as too low arc voltage, etc., are caused by so-called disturbances. At present, there is no method to monitor the stability of welding, and as a measure to stabilize welding, it is necessary to periodically clean the wire feed path, replace wire conduit cables,
These countermeasures have been taken after the welding tip was replaced or a welding defect occurred.

The groove tracking control method using an arc sensor is a method using the welding arc itself as a sensor. Therefore, if the welding arc is unstable, its performance is naturally deteriorated. Therefore, whether or not the arc sensor is working normally, that is, the applicability of the arc sensor largely depends on the stability of the welding arc. In addition, since there is no method for quantifying the applicability of the arc sensor, even if the arc sensor can be applied in the sample welding test in the laboratory, the welding conditions are not appropriate at the actual application site or the arc is affected by various disturbances. There were cases where the sensor could not be applied. The present invention has been made in order to solve such problems, when welding by performing groove tracking control by an arc sensor on a welded joint by a high-speed rotating arc welding method, to quantify the stability of welding,
It is an object of the present invention to provide a method and apparatus for determining welding stability, which can monitor the result and determine whether stable welding is performed.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for determining welding stability, comprising the steps of: providing a circular motion to an electrode nozzle of a welding torch; rotating an arc generated at a wire tip at a high speed; The voltage waveform or arc current waveform and the arc rotation position are detected, and the detected waveforms are integrated in the same phase angle range on the left and right around the center point in the forward direction of welding so that the integrated difference becomes zero. In a high-speed rotating arc welding method in which a welding torch is welded while performing groove tracing control by an arc sensor that corrects a torch position deviation in a groove width direction, a welding current waveform is integrated for each rotation of the arc. Calculating a variation amount of the obtained integral value over a predetermined number of times, comparing the obtained variation amount with at least one predetermined threshold value, and determining the variation amount by a threshold. Welding when exceeded is that as determined to be unstable.

[0006] A determination apparatus for performing the method for determining welding stability includes a welding current detector that detects a welding current of a welding torch to be welded by a high-speed rotating arc welding method, and a welding current that outputs a preset welding current reference value. A current reference value setting device, a differential amplifier that outputs a difference between a welding current detected by the welding current detector and a welding current reference value of the welding current reference value setting device, and a rotation position detection that detects a rotation position of the electrode nozzle. Means for outputting an output signal of the differential amplifier by a predetermined number of revolutions per rotation of the electrode nozzle based on a position detection signal of the rotation position detector, and an output signal for each rotation outputted by the gate means , A sample-and-hold circuit for holding the detection signal integrated by the integrator for one rotation, and a predetermined rotation number output from the sample-and-hold circuit. A standard deviation calculation circuit for calculating a standard deviation from the minute value; and a welding stability determination circuit for comparing the standard deviation calculated by the standard deviation calculation circuit with at least one predetermined threshold value and outputting a welding instability signal. It is provided with. Another method for determining welding stability according to the present invention is to provide a circular motion to an electrode nozzle of a welding torch to rotate an arc generated at the tip of a wire at a high speed, and to obtain an arc voltage waveform or an arc current waveform of the rotating arc. And the arc rotation position are detected, and the detected waveforms are integrated in the same phase angle range on the left and right with the center point in front of the welding progress direction as the center,
In a high-speed rotary arc welding method in which a welding torch is welded while performing groove tracing control by an arc sensor that corrects a torch position shift in a groove width direction so that the integrated difference becomes zero, the arc rotation position is changed. The arc voltage waveforms are respectively integrated within a predetermined range of 5 ° or more and 180 ° or less with respect to the forward point in the welding progress direction in the above, and a variation amount of the difference between the obtained left and right integrated values is calculated for a predetermined number of times. Then, the obtained variation is compared with at least one predetermined threshold value, and when the variation amount exceeds the threshold value, it is determined that the welding is unstable.

An apparatus for determining the welding stability includes an arc voltage detector for detecting an arc voltage between an electrode nozzle and a workpiece of a welding torch to be welded by a high-speed rotating arc welding method, and a rotation position of the electrode nozzle. And a gate means for outputting a detection signal of the arc voltage detector in two predetermined angle ranges set based on the position signal of the rotation position detector by a predetermined number of rotations per one rotation of the electrode nozzle. And two integrators respectively integrating the detection signals output by the gate means in two predetermined angle ranges per rotation, and two sample-and-holds holding the detection signals integrated by each integrator for one rotation Circuit, a differential amplifier that outputs the difference between the integrated values at a predetermined number of revolutions output from the two sample and hold circuits, and a differential amplifier. A standard deviation calculating circuit for calculating a standard deviation from a difference between the output integrated values, and welding for outputting a welding unstable signal by comparing the standard deviation calculated by the standard deviation calculating circuit with at least one predetermined threshold value And a stability determination circuit.

Further, another method of determining welding stability according to the present invention is to provide a method of making a circular motion to an electrode nozzle of a welding torch to rotate an arc generated at the tip of a wire at a high speed, and to set an arc voltage of the rotating arc. Detects the waveform or arc current waveform and the arc rotation position, integrates the detected waveforms in the same phase angle range on the left and right around the center point in front of the welding progress direction, and welds such that the integrated difference becomes zero. In a high-speed rotary arc welding method in which a torch is welded while performing groove tracking control using an arc sensor configured to correct a torch position deviation in a groove width direction, an arc voltage detected within a predetermined angle range in one rotation of an electrode nozzle. Is compared with a predetermined short-circuit detection level value to detect whether or not the arc voltage has become equal to or less than the short-circuit detection level value. Calculating the ratio of the number of detections in which the arc voltage has become equal to or less than the short-circuit detection level value to the total number of revolutions of the electrode nozzle within the temperature range to determine the short-circuit occurrence rate, and determining the short-circuit occurrence rate and at least one predetermined threshold value And when the short-circuit occurrence rate exceeds a threshold value, it is determined that the welding is unstable.

[0010] A determination device for performing the method for determining welding stability includes an arc voltage detector for detecting an arc voltage between an electrode nozzle of a welding torch to be welded by a high-speed rotating arc welding method and a workpiece, and a preset short-circuit detection level. A short-circuit detection level setting device that outputs a value, a rotation position detector that detects the rotation position of the electrode nozzle, and an arc voltage detection within a predetermined angle range in one rotation of the electrode nozzle based on a position detection signal of the rotation position detector. A short-circuit detection circuit that detects whether the arc voltage detected by the heater is equal to or less than the short-circuit detection level value of the short-circuit detection level setting device, and an arc voltage detected by the short-circuit determination circuit for the entire number of revolutions of the electrode nozzle is a short circuit detection level. A short circuit occurrence calculation circuit for calculating the ratio of the number of times of detection below the value to the total number of revolutions of the electrode nozzle to obtain a short circuit occurrence rate; The rate calculation circuit is configured by a welding stability determination circuit for comparing the short circuit rate was calculated with the predetermined at least one threshold and outputs a welding unstable signal.

[0010]

FIG. 1 is a block diagram showing an apparatus for determining welding stability according to one embodiment of the present invention. In the drawing, reference numeral 10 denotes a welding current detector for detecting a welding current flowing between a welding torch and a welding joint, 11 a welding current reference value setting device for setting a welding current reference value Io, and 12 a welding current detector 10. A differential amplifier for outputting a difference between the detected welding current Ia and the welding current reference value Io set by the welding current reference value setting device 11,
13 is a gate switch provided on the output side of the differential amplifier 12, 14 is a rotation position detector such as an encoder for detecting the rotation position of the electrode nozzle of the welding torch, and 15 is a position detection signal of the rotation position detector 14. A switch driving circuit that opens and closes the gate switch 13 based on the gate switch. 16 is a differential amplifier 12
An integrator provided on the output side of the device via a gate switch 13, a sample-and-hold circuit 17 for holding the detection signal integrated by the integrator 16 for one rotation, 1
Reference numeral 8 denotes a standard deviation calculating circuit for calculating a standard deviation based on the welding current from the integrated value at a predetermined number of revolutions output from the sample hold circuit 17, and 19 denotes a standard deviation calculated by the standard deviation calculating circuit 18 and two predetermined thresholds. The welding stability determination circuit 20 outputs two types of unstable signals indicating the welding unstable state by comparing the values with the values. Reference numeral 20 denotes a welding unstable state based on one of the welding unstable signals output from the welding stability determining circuit 19. Is an indicator that outputs a welding stop command based on the other welding instability signal output by the welding stability determination circuit 19 and displays the welding stop command.

Next, the operation of the apparatus for judging the stability of welding for implementing the method of the present invention will be described. When the electrode nozzle of the welding torch is performing welding while performing groove tracking control with an arc sensor on a weld joint by a high-speed rotating arc welding method, the welding current detector 10 changes the welding caused by the rotation of the electrode nozzle. The current is detected and the differential amplifier 12
Outputs the difference between the welding current reference value Io set by the welding current reference value setting device 11 and the welding current Ia.
The reason for obtaining such a difference is to increase the resolution of subsequent signal processing. The rotation position detector 14 detects the rotation position of the rotating electrode nozzle and outputs a position detection signal. In the switch drive circuit 15, among the difference signals output from the differential amplifier 12, the difference in the 360 ° angle range that is one rotation of the electrode nozzle set in advance based on the position detection signal of the rotation position detector 14. Drive control to open the gate switch 13 so as to output the signal to the integrator 16. 360 ° in the integrator 16
The sample and hold circuit 17 inputs the integrated value ΔI of the difference signal integrated by the integrator 16 to the standard deviation calculation circuit 18. The reason why the integration is performed by the integrator 16 is to prevent the welding current waveform from being affected by noise. The standard deviation calculation circuit 18 calculates a standard deviation from the integrated value for, for example, 500 rotations output from the sample hold circuit 17 by the following equation. In addition, it may be the number of rotations over the entire welding line.

[0012] The integrated value of the sample-and-hold circuit 17 the difference signal integrated by the integrator 16 for every one rotation output from the △ and I, the i-th signal of the (i-th rotation) and x _i, j-th Standard deviation S of the signal x _i from the kth to the kth
(The number of data n = k−j + 1) is expressed by the following equation.

(Equation 1) Thus, for each rotation (x _i ^2), obtained easy if we integrated respectively x _i. Thereafter, the welding stability judging circuit 19 compares the standard deviation S calculated by the standard deviation calculating circuit 18 with predetermined first and second thresholds s ₁ and s _2, and the standard deviation S becomes the first standard deviation. welding outputs a first weld unstable signal indicating that unstable when the above threshold s _1. Alarm 20 to which the first welding unstable signal is input
Then, an alarm indicating that the welding is unstable is output.
When the standard deviation S is equal to or greater than the _second threshold value s2, the second welding instability signal indicating that welding is more unstable is output. The display 21 to which the unstable signal is input outputs a welding stop command together with a display indicating that welding is stopped. As described above, for example, the standard deviation of the integral value of the waveform of the difference between the welding current detected at every rotation of the electrode nozzle and the welding current reference value for each rotation of the electrode nozzle for 50 to 5000 rotations, ie, each rotation. By comparing the standard deviation with the threshold value, it can be determined whether or not the welding is unstable. If the welding is stable, the above integral value for each rotation of the electrode nozzle is the same value. When the variation is small and the welding is unstable, the above-mentioned integrated value for each rotation of the electrode nozzle becomes a different value and the variation becomes large. Therefore, the standard deviation S of the above-mentioned integral value with respect to the predetermined number of rotations of the electrode nozzle is determined, and for example, the value of the standard deviation at the boundary between stability and instability of welding is set as a threshold, and the threshold and the standard deviation are set. If the standard deviation S is larger than the threshold value in comparison with S, it can be determined that the welding is unstable from the viewpoint of the torch height control based on the welding current.

As described above, when the welding is performed on the weld joint by performing the groove scanning control using the arc sensor by the high-speed rotating arc welding method, it is determined whether the welding becomes unstable or not based on the torch height based on the welding current. Since the determination can be made by quantifying and monitoring the welding stability from the viewpoint of control, it is possible to prevent welding defects from occurring frequently. It should be noted that the two thresholds are provided in order to quantitatively and stepwise grasp the unstable state of welding and to take appropriate measures according to the step.

FIG. 2 is a block diagram showing an apparatus for determining welding stability according to another embodiment of the present invention. In the drawing, reference numeral 30 denotes an arc voltage detector for detecting an arc voltage between a welding torch and a weld joint, 31 denotes an arc voltage reference value setter for setting an arc voltage reference value Eo, and 32 denotes an arc detected by the arc voltage detector 31. A differential amplifier that outputs a difference between the voltage Ea and the arc voltage reference value Eo set by the arc voltage reference value setting unit 31, 33a and 33b are gate switches provided on the output side of the differential amplifier 12, and 34 is a welding torch. Reference numeral 35 denotes a rotation position detector such as an encoder that detects the rotation position of the electrode nozzle. Reference numeral 35 denotes a switch drive circuit that opens and closes the gate switches 33a and 33b based on the position detection signal of the rotation position detector 33. 33b
And gate means. 36a and 36b are gate switches 33a and 33b on the output side of the differential amplifier 32.
The sample and hold circuits 37a and 37b hold the detection signals integrated by the integrators 36a and 36b for one rotation, respectively.
Reference numeral 8 denotes a differential amplifier for calculating a difference between the integrated values output from the two sample-hold circuits 37a and 37b, 39
Is a standard deviation calculating circuit for calculating a standard deviation from a difference between integral values at a predetermined number of revolutions output from the differential amplifier 38;
0 is a welding stability determination circuit that compares the standard deviation calculated by the standard deviation calculation circuit 39 with two predetermined thresholds and outputs two types of welding instability signals indicating a welding instability state.
Reference numeral 1 denotes an alarm unit for outputting an alarm indicating an unstable welding state based on one of the welding instability signals output from the welding stability determination circuit 41, and reference numeral 42 denotes a signal for the other welding instability signal output from the welding stability determination circuit 40. It is a display that outputs a welding stop command and displays welding stop based on the command.

Next, the operation of the welding stability determining apparatus for carrying out another method of the present invention will be described. When the electrode nozzle of the welding torch is performing welding while performing groove tracking control with an arc sensor on a weld joint by a high-speed rotating arc welding method, the arc voltage detector 30 outputs an arc that is changed by the rotation of the electrode nozzle. Detect the voltage,
The differential amplifier 32 outputs the difference between the arc voltage reference value Eo set by the arc voltage reference value setting device 31 and the arc voltage Ea. The reason for obtaining such a difference is to increase the resolution of subsequent signal processing. The rotation position detector 34 detects the rotation position of the rotating electrode nozzle and outputs a position detection signal. Then, in the switch drive circuit 35, of the difference signals output from the differential amplifier 32, based on the forward point Cf in the welding progress direction at the arc rotation position set in advance based on the position detection signal of the rotation position detector 34, An angle range of 90 ° which is, for example, 0 ° to 90 ° on the right R side (G is the origin and an angle in the R direction, the same applies hereinafter) and a range of 270 ° to 0 ° which is the left L side, for example The driving control for opening the gate switches 33a and 33b is performed so that a signal having a difference of 90 ° in the angle range is output to the integrators 36a and 36b, respectively. The integrator 36a integrates the difference signal in the 90-degree angle range on the R side, and the integrator 36b integrates the signal on the L side 90 °.
The difference signal in the angle range of ° is integrated, the sample-and-hold circuit 37a inputs the integrated value of the difference signal integrated by the integrator 36a to the differential amplifier 38, and the sample-and-hold circuit 37b is integrated by the integrator 36b. The integrated value of the difference signal is input to the differential amplifier 38. The integration by the integrators 36ba and 36b is performed in order to prevent the arc voltage waveform from being affected by noise. In the differential amplifier 38, the integrated value S1 by the integrator 36a is obtained.
The difference ΔS between the calculated value and the integral value S2 is obtained and output to the standard deviation calculating circuit 39. The standard deviation calculating circuit 39 calculates the standard deviation of the difference ΔS of the integral value obtained by the differential amplifier 38 for, for example, 500 rotations.

Thereafter, the welding stability determination circuit 40 compares the standard deviation S calculated by the standard deviation calculation circuit 39 with predetermined first and second threshold values s ₁ and s _2, and the standard deviation S There welded when the first threshold value s ₁ or higher to output a first weld unstable signal indicating that unstable. The alarm 20 to which the first welding instability signal is input outputs an alarm indicating that welding is unstable. When the standard deviation S is equal to or greater than the _second threshold value s2, the second welding instability signal indicating that welding is more unstable is output. The display 42 to which the second unstable signal is input
Then, a welding stop command is output together with the stop of welding. In this embodiment, whether or not welding is unstable is determined from the viewpoint of groove tracing control by an arc sensor based on an arc voltage.

FIG. 3 is a block diagram showing a welding stability determining apparatus according to another embodiment of the present invention. In the figure, reference numeral 50 denotes an arc voltage detector for detecting an arc voltage between a welding torch and a welding joint, and reference numeral 51 denotes a short-circuit detection level value which is a threshold value for determining whether or not a short circuit has occurred when the arc voltage has decreased due to a short circuit. Short-circuit detection level detector, 5
2 is a rotational position detector such as an encoder for detecting the rotational position of the electrode nozzle of the welding torch, 53 is a rotational position detector 52
Short-circuit determination circuit for detecting whether or not the arc voltage detected by the arc voltage detector 50 falls below the short-circuit detection level of the short-circuit detection level setting unit 51 within the angular range of one rotation of the electrode nozzle based on the position detection signal of And 54 are short circuits for calculating the ratio of the total number of rotations of the electrode nozzle to the ratio of the number of times that the arc voltage detected by the short circuit determination circuit 53 with respect to the total number of rotations of the electrode nozzle has fallen below the short circuit detection level value to obtain the short circuit occurrence rate. An occurrence rate calculation circuit 55 is a welding stability determination circuit that compares the short-circuit occurrence rate calculated by the short-circuit occurrence rate calculation circuit 54 with two predetermined thresholds and outputs a welding instability signal. An alarm device that outputs an alarm indicating an unstable welding state based on one of the welding instability signals output from the determination circuit 55, and 57 is the other output from the welding stability determination circuit 55 A display for displaying the welding stop and outputs a welding stop signal on the basis of the welding unstable signal.

Next, the operation of the welding stability judging device for implementing another method of the present invention will be described. When the electrode nozzle of the welding torch is performing welding while performing groove tracking control with an arc sensor on a weld joint by a high-speed rotating arc welding method, the arc voltage detector 30 outputs an arc that is changed by the rotation of the electrode nozzle. The voltage is detected and output to the short circuit determination circuit 53. The rotation position detector 52 also outputs a position detection signal to the short circuit determination circuit 53. In the short-circuit determination circuit 53, the arc voltage detected by the arc voltage detector 50 within the angular range of one rotation of the electrode nozzle based on the position detection signal of the rotation position detector 52 is used to set the short-circuit detection level set by the short-circuit detection level setting unit 51. It is determined whether or not the arc voltage has become equal to or less than the short-circuit detection level value. Short circuit occurrence rate calculation circuit 54
Then, the ratio of the number of short-circuit occurrence signals output by the short-circuit determination circuit 53 to the total number of rotations of the electrode nozzle calculated based on the position detection signal of the rotation position detector 52 is calculated with respect to the total number of rotations of the electrode nozzle. The short circuit occurrence rate Rs is determined. The short-circuit occurrence rate Rs is represented by the following equation. Short-circuit occurrence rate Rs (%) = [the number of times the arc voltage becomes equal to or less than the short-circuit detection level value at all the electrode nozzle rotation speeds / the rotation speed of the electrode nozzles] × 100 In the sex determination circuit 55, the short circuit occurrence rate calculation circuit 54
Is compared with _two predetermined threshold values s ₁ and s _{2. When} the short-circuit occurrence ratio RS is equal to or greater than a _first threshold value s ₁ , for example, 50%, welding is unstable. Is output indicating that the welding is unstable. The alarm 56 to which the unstable signal is input outputs an alarm indicating that welding is unstable. In addition, the short circuit occurrence rate RS is the second
When the threshold value is s ₂ , for example, 70% or more, a second unstable signal indicating that welding is more unstable is output. The display 57 to which the second unstable signal is input outputs a welding stop command together with a display indicating that welding is stopped.

In this embodiment, it is determined whether or not the welding is unstable from the viewpoint of whether or not the arc voltage has decreased due to the short circuit. This method is an effective method for judging welding stability especially when short-circuiting easily occurs during welding with a small current in a small current region in which a droplet transfers to a short circuit in which a droplet transfers to a short circuit. 1 and 2, the instability of welding can be determined regardless of the magnitude of the welding current. Also, FIGS. 1, 2 and 3
In any of the examples shown in the above, it is possible to quantitatively independently determine the welding stability, but by combining these, if the welding stability can be determined for any one,
It goes without saying that the judgment may not be made for the others. Further, in all of the above-described embodiments, the standard deviation is used as the amount of variation, but it is needless to say that a value indicating the amount of variation other than the standard deviation may be used. Further, the standard deviation is obtained from the detection value of the predetermined number of times, but may be obtained from the detection value in a certain time.

[0020]

As described above, the present invention applies a circular motion to the electrode nozzle of the welding torch to rotate the arc generated at the tip of the wire at a high speed, and the arc voltage waveform or the arc current waveform of the rotating arc and the arc rotation position. And the detected waveforms are integrated in the same phase angle range on the left and right centering on the center point in front of the welding progress direction, and the welding torch is positioned in the groove width direction so that the integrated difference becomes zero. When welding is performed while performing groove tracking control by an arc sensor on a workpiece by a high-speed rotating arc welding method for correcting misalignment, the welding current waveform is changed to one of arc rotation.
Integrate for each rotation, calculate the amount of variation of the obtained integrated value over a predetermined number of times, compare the obtained amount of variation with at least one predetermined threshold value, and determine that the amount of variation exceeds the threshold value. Is determined to be unstable when welding is performed, or the left and right arc voltage waveforms obtained by integrating the arc voltage waveforms within a predetermined range of 5 ° or more and 180 ° or less around the forward point of the welding progress direction at the arc rotation position. The variation of the difference between the integral values is calculated over a predetermined number of times, and the obtained variation is compared with at least one predetermined threshold value. When the variation exceeds the threshold value, welding becomes unstable. Or the arc voltage detected within a predetermined angle range in one rotation of the electrode nozzle is compared with a predetermined short-circuit detection level value, and the arc voltage is equal to or less than the short-circuit detection level value. Is detected, and the ratio between the number of detections in which the arc voltage is equal to or less than the short-circuit detection level value and the total number of rotations of the electrode nozzle within the predetermined angle range with respect to the total number of rotations of the electrode nozzle is calculated. Find the incidence,
The short-circuit occurrence rate is compared with at least one predetermined threshold value, and when the short-circuit occurrence rate exceeds the threshold value, it is determined that the welding is unstable. Stability can be quantified and monitored, and there is an effect that frequent occurrence of welding defects can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an apparatus for determining welding stability according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a welding stability determination device according to another embodiment of the present invention.

FIG. 3 is a block diagram showing a welding stability determination device according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a groove tracing control method using a conventional arc sensor.

[Explanation of symbols]

 Reference Signs List 10 welding current detector 11 welding current reference value setting device 12 differential amplifier 13 gate switch (gate means) 14 rotation position detector 15 switch drive circuit (gate means) 16 integrator 17 sample hold circuit 18 standard deviation calculation circuit 19 Welding stability judgment circuit

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-71178 (JP, A) JP-A-3-18479 (JP, A) JP-A-62-248571 (JP, A) JP-A-61-248 71179 (JP, A) JP-A-1-118176 (JP, A)

Claims (6)

(57) [Claims] 1. A circular motion is applied to an electrode nozzle of a welding torch.
To rotate the arc generated at the tip of the wire at high speed.
Arc voltage waveform or arc current waveform
The rotation position is detected, and the center point is in front of the welding progress direction.
The detected waveforms are integrated over the same phase angle range
Groove welding torch so that their integrated difference is zero
In a high-speed rotary arc welding method in which welding is performed while performing groove tracing control using an arc sensor configured to correct the displacement of the torch in the width direction , a welding current waveform is integrated for each rotation of the arc, and the obtained integration is obtained. The variation of the value is calculated for a predetermined number of times, and the obtained variation is compared with at least one predetermined threshold. When the variation exceeds the threshold, it is determined that welding is unstable. A method for determining welding stability. 2. A circular motion is applied to an electrode nozzle of a welding torch.
To rotate the arc generated at the tip of the wire at high speed.
Arc voltage waveform or arc current waveform
The rotation position is detected, and the center point is in front of the welding progress direction.
The detected waveforms are integrated over the same phase angle range
Groove welding torch so that their integrated difference is zero
Apparatus used for high-speed rotary arc welding that performs welding while performing groove tracing control using an arc sensor that corrects misalignment of the torch in the width direction. A welding current detector for detecting current, a welding current reference value setting device for outputting a preset welding current reference value, a welding current detected by the welding current detector, and a welding current reference value for the welding current reference value setting device. Differential amplifier that outputs the difference between the two, a rotational position detector that detects the rotational position of the electrode nozzle, and an output signal of the differential amplifier that is rotated by a predetermined rotation every one rotation of the electrode nozzle based on the position detection signal of the rotational position detector. Gate means for outputting a number of signals, an integrator for integrating the output signal for each rotation outputted by the gate means, and a detection signal integrated by the integrator for one rotation. A sample and hold circuit, a standard deviation calculation circuit for calculating a standard deviation of an integrated value at a predetermined number of revolutions output from the sample and hold circuit, a standard deviation calculated by the standard deviation calculation circuit, and at least one predetermined threshold value. And a welding stability determination circuit that outputs a welding instability signal by comparing the two. 3. A circular motion is applied to an electrode nozzle of a welding torch.
To rotate the arc generated at the tip of the wire at high speed.
Arc voltage waveform or arc current waveform
The rotation position is detected, and the center point is in front of the welding progress direction.
The detected waveforms are integrated over the same phase angle range
Groove welding torch so that their integrated difference is zero
In a high-speed rotary arc welding method in which welding is performed while performing groove tracing control by an arc sensor configured to correct a displacement of a torch position in a width direction , a left or right of 5 ° or more and 180 ° centered on a forward point in a welding traveling direction at an arc rotation position Each of the arc voltage waveforms is integrated within the following predetermined ranges, and the obtained variation amount of the difference between the left and right integrated values is calculated over a predetermined number of times, and the obtained variation amount and at least one threshold value are calculated. And determining that welding is unstable when the variation exceeds a threshold value. 4. A circular motion is applied to an electrode nozzle of a welding torch.
To rotate the arc generated at the tip of the wire at high speed.
Arc voltage waveform or arc current waveform
The rotation position is detected, and the center point is in front of the welding progress direction.
The detected waveforms are integrated over the same phase angle range
Groove welding torch so that their integrated difference is zero
Apparatus used for high-speed rotary arc welding that performs welding while performing groove contouring control by an arc sensor that corrects misalignment of the torch in the width direction. The welding torch electrode to be welded by high-speed rotary arc welding. A voltage detector that detects an arc voltage between the nozzle and the workpiece, a rotation position detector that detects the rotation position of the electrode nozzle, and an arc voltage detection in two predetermined angle ranges set based on a position signal of the rotation position detector. Means for outputting a detection signal of the detector by a predetermined number of revolutions for each rotation of the electrode nozzle, and two gates for each rotation output by the gate means.
Two integrators for respectively integrating detection signals in two predetermined angle ranges, two sample and hold circuits for holding the detection signals integrated by each integrator for one rotation,
A differential amplifier that outputs a difference between integrated values at a predetermined number of revolutions output from the two sample and hold circuits, a standard deviation calculation circuit that calculates a standard deviation from a difference between the integrated values output from the differential amplifier, and a standard deviation A welding stability determining circuit for comparing the standard deviation calculated by the calculating circuit with at least one predetermined threshold value and outputting a welding instability signal. 5. A circular motion is applied to an electrode nozzle of a welding torch.
To rotate the arc generated at the tip of the wire at high speed.
Arc voltage waveform or arc current waveform
The rotation position is detected, and the center point is in front of the welding progress direction.
The detected waveforms are integrated over the same phase angle range
Groove welding torch so that their integrated difference is zero
In a high-speed rotating arc welding method in which welding is performed while performing groove tracing control using an arc sensor that corrects the displacement of the torch in the width direction, an arc voltage detected within a predetermined angle range in one rotation of the electrode nozzle is short-circuited for a predetermined time. Compared with the detection level value, it was detected whether or not the arc voltage was equal to or less than the short-circuit detection level value, and the arc voltage was equal to or less than the short-circuit detection level value within the predetermined angle range with respect to the entire number of revolutions of the electrode nozzle. The ratio of the number of detections to the total number of revolutions of the electrode nozzle is calculated to determine the short-circuit occurrence rate, and the short-circuit occurrence rate is compared with at least one predetermined threshold value. A method for determining welding stability, wherein it is determined that the welding is unstable when the welding is performed. 6. A circular motion is applied to an electrode nozzle of a welding torch.
To rotate the arc generated at the tip of the wire at high speed.
Arc voltage waveform or arc current waveform
The rotation position is detected, and the center point is in front of the welding progress direction.
The detected waveforms are integrated over the same phase angle range
Groove welding torch so that their integrated difference is zero
Apparatus used for high-speed rotary arc welding that performs welding while performing groove contouring control by an arc sensor that corrects misalignment of the torch in the width direction. The welding torch electrode to be welded by high-speed rotary arc welding. An arc voltage detector for detecting an arc voltage between the nozzle and the workpiece, a short-circuit detection level setter for outputting a preset short-circuit detection level value, a rotation position detector for detecting the rotation position of the electrode nozzle, and a rotation position detection Short-circuit determination for detecting whether or not the arc voltage detected by the arc voltage detector falls below the short-circuit detection level value of the short-circuit detection level setting device within a predetermined angle range in one rotation of the electrode nozzle based on the position detection signal of the heater. Circuit and the number of times that the arc voltage detected by the short circuit determination circuit with respect to the total number of rotations of the electrode A short circuit occurrence calculating circuit for calculating the ratio of the short circuit occurrence by calculating the ratio to the total number of revolutions of the nozzle; and comparing the short circuit occurrence calculated by the short circuit occurrence calculation circuit with at least one predetermined threshold value to perform welding. A welding stability determination device, comprising: a welding stability determination circuit that outputs an unstable signal.