JPH0630810B2 - Control device of automatic arc welding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an automatic arc welding machine, and sometimes weaving a welding torch along a welding line to automatically perform arc welding, and The present invention relates to a controller for an automatic arc welder that detects an arc current due to weaving with a sensor and compensates for movement of a welding torch.

[Conventional technology]

The automatic arc welding machine weaves the welding torch along the welding line of the base metal to be welded, and at the same time, detects the arc current due to the weaving with the arc sensor to compensate the movement of the welding torch and Is automatically arc-welded. That is, in order to accurately move the welding torch along the welding line of the base material, the arc current detected by the arc sensor is processed to compensate the movement of the welding torch.

FIG. 7 is a view showing a manner of welding a downward facing joint by a control device of a conventional automatic arc welding machine.

As shown in FIG. 7, for example, a welding member 11 having a vertical surface and a welding member 12 having a surface forming an acute angle with respect to the vertical direction constitute a re-shape, and the welding of the downward re-shaped joint is performed. When the welding torch 5 is moved by weaving along the line 13 to perform arc welding, the welding torch 5 is moved symmetrically about the bisector of the angle formed by the welding members 11 and 12, and the welding line 13 is moved. A bead 14 formed by melting a welding wire or the like is accumulated on the upper part of the.

By the way, the surface of the bead 14 accumulated above the welding line 13 becomes horizontal due to the action of gravity, and the bead 14 is welded to the welding member 1
There is no symmetry about the bisector of the angle formed by 1 and 12. That is, the distance between the tip of the welding wire 51 of the welding torch 5 performing the weaving movement and the surface of the bead 14 is separated on the side of _one end A ₁ and approaches on the side of the other end C _1. . Here, the arc discharge in the arc welding is generated between the tip of the welding wire 51 of the welding torch 5 and the metal closest to the tip of the welding wire. The arc current flowing from the tip of the welding wire 51 to the metal closest to the tip of the welding wire when performing welding by arc discharge is defined by the distance between the tip of the welding wire 51 and the metal closest to the tip of the welding wire. It is something.

Specifically, in the case of welding the downward-recessed joint of FIG. 7, when the tip of the welding wire 51 moves to the _one end A ₁ , an arc discharge occurs between the tip of the welding wire 51 and the welding member 11, Further, the tip of the welding wire 51 has the other end C.
When moving to ₁ , the tip of the welding wire 51 and the bead 1
An arc discharge will occur between 4 and 4.

[Problems to be solved by the invention]

As described above, the conventional control device for the automatic arc welding machine, for example, in the case of welding a downward-facing R-shaped joint, when the tip of the welding wire 51 moves to the _one end A ₁ , the tip of the welding wire 51 and the welding member. arc discharge is generated between the 11, also when the welding wire 51 distal end is moved to the other end C ₁ an arc discharge is generated between the welding wire 51 tip and the bead 14, along the weld line 13 Even if the weaving movement is accurate, the symmetrical arc current cannot be obtained.

Therefore, as shown in FIG. 8, the area of the arc current when the tip of the welding wire 51 moves from _one end A ₁ to the central position B ₁ (the arc current is integrated from time t ₁ to time t ₃ ). Value) S _1a and the area of the arc current when the tip of the welding wire 51 moves from the central position B ₁ to the other end C ₁ (value obtained by integrating the arc current from time t ₃ to time t ₂ ) S _2a If the movement of the welding torch 5 is compensated on the basis of the time when the values become equal, the welding torch 5 cannot be accurately corrected along the actual welding line 13. When compensating for the movement of the welding torch 5 as a reference when the two area S _1a and S _2a described above is equal, i.e., the area S _2a value area S _1a bead 14 acts is larger If the movement of the welding torch 5 is compensated so as to be equal to the welding torch 5, the welding torch 5 approaches the welding member 11 too much at _one end A ₁ , so that the arc discharge generated between the welding torch 5 and the tip of the welding wire 51 causes the welding member 11 Was also melted to cause undercut 11a.

Also, in addition to arc welding of the downward facing joint, for example,
Two areas of arc current (S _1a , S _2a ) in arc welding of a lap joint where thin metal plates are overlapped and welded on top
If the movement of the welding torch 5 is compensated so that
It was not possible to perform accurate welding on the welding line, and the bead was unevenly welded on the side where the thin metal plates were stacked.

The object of the present invention is calculated by setting the area treatment parameter according to the welding conditions and integrating the arc current by the time of every 1/4 cycle in view of the problems of the control device of the conventional automatic arc welding machine described above. The first correction area is calculated by multiplying the first area of the two areas by the parameter, and the size of the first correction area and the second area of the two areas is compared and discriminated. By compensating the movement of the welding torch, it is possible to perform accurate arc welding on the base material of various shapes along the welding line of the base material.

[Means for solving problems]

FIG. 1 is a block diagram showing the principle of a control device for an automatic arc welding machine according to the present invention.

According to the present invention, automatic arc welding that weaves the welding torch along the welding line to automatically perform arc welding, and detects the arc current due to the weaving with an arc sensor to compensate for movement of the welding torch. Which is a control device for a machine, and which has an area processing parameter setting means 1 for setting an area processing parameter according to welding conditions, the arc current is detected every half cycle of weaving, and the arc current is integrated over time to 1/4. An area calculation means 2 for calculating two areas for each cycle, a correction area calculation means 3 for calculating a first correction area by multiplying a first area of the two areas by the parameter, and the first area. Comparison discriminating means 4 for comparing and discriminating the size of the corrected area and the second area of the two areas, and a reference value when the first corrected area and the second area are different. And a movement compensating means 5 for compensating for the movement of the welding torch.

[Operation] According to the control device of the automatic arc welding machine of the present invention having the above-described configuration, the welding torch is weaved along the welding line to automatically perform the arc welding, and the arc current generated by the weaving is the arc current. Detected by the sensor, the movement of the welding torch is compensated. Then, the area processing parameter setting means 1 sets the area processing parameter according to the welding condition, and the area calculating means 2 integrates the arc current at each 1/4 cycle to calculate two areas. Further, the correction area calculating means 3 calculates the first correction area by multiplying the first area of the two areas by the above parameter, and the comparing and judging means 4 calculates the first correction area and the two areas. The second area is compared with the second area. Further, when the first corrected area and the second area are different, the movement compensating means 5 corrects the reference value to compensate the movement of the welding torch. As a result, accurate arc welding can be performed on various shapes of base material along the welding line of the base material.

〔Example〕

An embodiment of a control device for an automatic arc welding machine according to the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram schematically showing the control device of the automatic arc welding machine according to the present invention.

The welding torch 5 arc-welds the base material while feeding the welding wire 51, and generates an arc between the tip of the welding wire 51 and the base material by a voltage applied by a welding power source (not shown). It is designed to let you. The arc current passed between the tip of the welding wire 51 and the base material is measured by the arc sensor 8, and the arc current data is supplied to the microprocessor 7. Further, the welding torch 5 is moved and controlled by a welding torch moving device 6 which operates according to a command from the microprocessor 7, so that the welding torch moving device 6 carries out a movement along the welding line of the base metal and a weaving operation. Has been done. Here, the storage device 9 stores the correction function and the like, and stores the storage data of the correction function and the like in accordance with a command from the microprocessor 7.
It can be sent to.

FIG. 3 is a view showing a state in which a downward-facing downward joint is welded by the control device of the automatic arc welding machine according to the present invention. FIGS. 4 (a) and 4 (b) show the arc current and the arc current detected in FIG. It is a figure which shows the arc current amended according to welding conditions.

As shown in FIG. 3, for example, a welding member 11 having a vertical surface and a welding member 12 having an acute-angled surface with respect to the vertical direction form a checkered shape, and a welding line 13 of this downwardly facing joint is formed. When the welding torch 5 is moved by weaving along the line to perform arc welding, the welding torch 5 is welded to the welding member at one end A by welding the downward joint by the controller of the automatic arc welding machine of the present invention. 11 will not be too close to cause undercutting of the welded member 11.

As shown in FIG. 4 (a), the area of the arc current when the tip of the welding wire 51 moves from one end A to the central position B (value obtained by integrating the arc current from time T ₁ to time T ₃ ). ) S ₁ and the area of the arc current when the tip of the welding wire 51 moves from the central position B to the other end C (a value obtained by integrating the arc current from time T ₃ to time T ₂ ).
When S ₂ is equal, these two areas S ₁ and S
Matters ₂ are identical immediately welding torch 5 is weld line 13
It is not determined that the weaving movement is accurate along. That is, in the case of welding a downward joint having a downward shape as shown in FIG. 3, the tip of the welding wire 51 is the other end C.
The magnitude of the arc current at the position of
Due to the influence of, the arc sensor detects a larger value than when the tip of the welding wire 51 is at the position of the one end A. If the control device for the automatic arc welding machine according to the present embodiment is used, for example, as shown in FIG. 4 (a), two areas S of the arc current waveform detected in the welding of the downward facing joint can be detected. _{When 1} and S ₂ match,
The area S ₂ having a large value due to the bead 14 is corrected and the corrected area S _2b and the area S ₁ are compared, and the corrected area S _2b and the area S ₁ are compared and discriminated. According to the result, the weaving movement of the welding torch 5 is compensated.

Further, as shown in FIG. 5, the control device of the automatic arc welding machine according to the present invention can not only accurately perform arc welding with respect to the above-mentioned downward joint, but also, for example, with respect to corner joints. By setting the area processing parameter according to the condition, for example, the leg lengths 14a and 1 of the bead 14 are set.
4b can be different.

Hereinafter, an example of the control operation according to the present invention will be described with reference to the flowchart of FIG.

First, in step 60, the area processing parameter P is set according to the welding conditions. The welding conditions in this step 60 are, for example, conditions such as correction of the area of the arc current waveform by the above-mentioned special joint shape and designation of the leg length of the bead in fillet welding.

In step 60, the area processing parameter P according to the welding conditions
Is set, the process proceeds to step 61, where the welding torch 5 is moved by a half period of weaving according to the reference value,
Further, in step 62, the arc sensor 8 detects the arc current. Here, to move the weaving half cycle according to the reference value means to move the welding torch 5 along the taught welding line, and the reference value is stored in advance in the storage device 9 or the like. .
After the arc current is detected by the arc sensor 8 in step 62, the arc current is integrated over time in step 63 to calculate _two areas S ₁ and S ₂ for each ¼ cycle. Then, in step 64, the area processing parameter P set in accordance with the welding conditions in step 60 is multiplied by one of the _two areas S ₁ and S ₂ . Here, the value of the parameter P and the area of one side by which the parameter P is multiplied are defined by the welding conditions. For example, in the case of the downward-angled joint of FIG. 3 and FIG. It is the other area S ₂ obtained by integrating the arc current from T ₃ to time T ₂ , and the value of the parameter P satisfies the condition of P <1. Then, in step 64, the corrected area S _2b (= S ₂ · P) is calculated.

Furthermore, the routine proceeds to step 65, where it is judged if S ₁ · P = S ₂ (or S ₂ · P = S ₁ ). In the case of FIGS. 3 and 4 described above, the correction area S _2b and the time T
_One area S where the arc current is integrated from ₁ to time T _3
It is compared and discriminated whether ₁ and ₁ match. That is,
It is determined whether S ₂ · P = S ₁ holds. Then, in step 65, S ₁ · P = S ₂ (or S ₂ ·
P = S ₁ ) is established (in the case of FIG. 3 and FIG. 4, it is determined that the corrected area S _2b and one area S ₁ are the same), that is, the welding torch 5 has a predetermined value. If it is determined that the position is weaving correctly, the process proceeds to step 67 and it is determined whether the condition is the end condition. The termination condition is a condition such as the length of the welding line stored in advance. If it is determined in step 67 that the termination condition is satisfied, the welding torch movement correction process is terminated.
Further, when it is determined in step 67 that the ending condition is not satisfied, the process returns to step 61, and the welding torch 5 is moved by the weaving half cycle according to the reference value.

In step 65, S ₁ · P = S ₂ (or S ₂ ·
P = S ₁ ) is not established (in the case of FIGS. 3 and 4, it is determined that the corrected area S _2b and one area S ₁ do not match), that is, the welding torch 5 is When it is determined that the weaving movement is not performed correctly at the predetermined position, the routine proceeds to step 66, where the reference value is corrected. When the reference value is corrected in step 66, step 6
Then, the process proceeds to step 8 and it is judged whether or not the condition is the end condition. This end condition is similar to the end condition in step 67, and is, for example, a condition such as the length of the welding line stored in advance. When it is determined in step 68 that the ending condition is satisfied,
The movement correction process of the welding torch ends. When it is determined in step 68 that the ending condition is not satisfied, the process proceeds to step 69, in which the welding torch 5 is moved by the weaving half cycle according to the correction value, and the process proceeds to step 62. Here, the correction value is a value obtained by correcting the reference value by the correction function in step 66.

As described in detail, the welding torch movement correction process is repeated every half cycle of weaving until it is determined in step 67 and step 68 that the termination condition is satisfied.

In the above, the control device of the automatic arc welding machine of the present invention can not only accurately perform arc welding with respect to the downward curved joint, but also set the area treatment parameter for the corner joint depending on the welding conditions. Bead 1
As described above, the leg lengths 14a and 14b of No. 4 can be made different. Further, the correction of the reference value in step 66 can be performed by using various conventionally known various correction functions and various correction methods.

〔The invention's effect〕

As described above in detail, the control device for the automatic arc welding machine according to the present invention sets two area processing parameters in accordance with the welding conditions and integrates the arc current with the time for each ¼ cycle to calculate two values. The first correction area is calculated by multiplying the first area of the area by the parameter, and the size of the first correction area and the second area of the two areas is compared and discriminated to determine the welding torch. By compensating for the movement of the base metal, it is possible to perform accurate arc welding on the base metal of various shapes along the welding line of the base metal.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of a control device for an automatic arc welding machine according to the present invention, FIG. 2 is a block diagram schematically showing a control device for an automatic arc welding machine according to the present invention, and FIG. FIG. 4 is a diagram showing a state in which a downward joint is welded by the control device of the automatic arc welding machine of FIGS. 4 (a) and 4 (b) shows the arc current detected in FIG. 3 and the arc current corrected by the welding conditions. FIG. 5, FIG. 5 is a view showing a bead shape when welding conditions are set by a control device of an automatic arc welding machine according to the present invention, FIG. 6 is a flowchart showing an example of a control operation according to the present invention, and FIG. FIG. 8 is a diagram showing a state in which a downward coupling is welded by a control device of a conventional automatic arc welding machine, and FIG. 8 is a diagram showing arc currents detected in FIG. 7. (Explanation of symbols) 1 ... area processing parameter setting means, 2 ... area calculating means, 3 ... comparison / determining means, 4 ... movement compensating means, 5 ... welding torch, 6 ... welding torch moving device, 7 ... Microprocessor, 8 ... Arc sensor, 9 ... Storage device.

Front page continued (72) Inventor Yuichi Kanda 3-5-5 Asahigaoka, Hino-shi, Tokyo FANUC CORPORATION Product Development Laboratory (72) Inventor Shigehiro Morikawa 3-5-1 Asahigaoka, Hino-shi, Tokyo FANUC CORPORATION Product Development Laboratory

Claims (1)

[Claims] 1. An automatic arc welding machine for weaving a welding torch along a welding line to automatically perform arc welding, and detecting an arc current by the weaving with an arc sensor to compensate for movement of the welding torch. An area processing parameter setting means (1) for setting an area processing parameter according to welding conditions; and detecting the arc current every half cycle of weaving,
Area calculation means (2) for integrating the arc current over time to calculate two areas for each 1/4 cycle; and a first correction of the first area of the two areas by multiplying the parameter. Corrected area calculating means (3) for calculating the area
And a comparison determination unit (4) for comparing and determining the magnitude of the first corrected area and the second area of the two areas, and the first corrected area and the second area are different. When
A controller for an automatic arc welder, comprising: a movement compensating means (5) for correcting a reference value to compensate for the movement of the welding torch.