JPH08118017A - Automatic welding equipment - Google Patents

Abstract

PURPOSE: To excellently detect the defect of the weld bead in an automatic welding equipment having a defect detecting device to detect the defect of the weld bead. CONSTITUTION: An automatic welding equipment to perform the welding action to control the copying of the weld line of a welding torch 4 based on the information of a groove position detecting sensor 7 and a defect detecting action to detect and display the defect of the weld bead based on the information of a defect detecting sensor 8 is provided with an integrated control device 17 which divides the welding action and the defect detecting action in a time- sharing manner and realizes them. Because the defect is detected when a traveling truck is returned after the welding, the defect can be detected at the desired distance intervals. Because no welding light affects the detection of the defect, the defect can be reliably detected. The defect is detected slightly after the welding, and the defects such as the weld crack can be surely detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic welding apparatus having a defect detecting device for detecting a defect of a welding bead, and more particularly to an automatic welding device capable of excellently detecting a defect of a welding bead.

[0002]

2. Description of the Related Art In manufacturing pipes, pressure vessels, etc.,
It is necessary to perform welding of thick plates, and it is necessary to perform multi-pass multi-pass welding. Further, these pressure vessels, pipes, etc. are often used at high temperature and high pressure, and high welding quality level is required. These high-quality welds are produced by a well-trained welder who has long experience and has little welding defects such as cracks.
It is implemented by applying G welding. But,
TIG welding has a lower welding efficiency than other welding methods and is disadvantageous in terms of cost, and it is expected that it will be difficult to secure skilled welders in the future. Therefore, multi-layer multi-pass automatic TIG welding equipment Development is needed.

In conventional manual TIG welding, a welder moves a welding torch position to an optimum position by observing deformation of a groove due to welding heat. Then, after each welding of each pass, the weld bead shape and the surface condition are visually confirmed, and the presence or absence of welding defects such as open blowholes, weld cracks, undercuts, and overlaps is checked. The next pass is welded. At this time, if the above-mentioned welding defect is found, the defect may be removed by a grinder or the like, or the bead shape may be corrected by welding without adding a wire.

[0004] As an example of automating the investigation of these welding and welding defects, "Situation Judgment by Visual and Auditory Information of TIG Welding (Part 2)"
There is a third collection, p222-223, '93 -9).

In the above-mentioned conventional example, a welding condition imaging device comprising a CCD black and white camera and a laser slit light source is provided near the welding electrode, and the welding condition imaging device senses the groove width immediately after welding, the electrode, the bead shape and the like. To do. Then, the groove is traced based on the information, and the quality of the bead shape is determined, and the welding is performed "as is" or "welding is stopped".
It is an automatic welding device that does the above.

[0006]

However, the conventional technique has the following problems because it detects a welding defect while performing welding.

1) When the content of processing for defect detection is determined, the processing time for that is determined. Therefore, if a welding defect is detected while welding is performed, the defect detection interval in the welding advancing direction depends on the welding speed. Therefore, the desired defect detection interval in the welding progress direction cannot be obtained.

2) Welding light affects the defect detection device. For this reason, the reliability of the defect detection device is reduced.

3) Defects such as weld cracks occur during the process of solidification of the molten pool. Further, when the molten pool solidifies, angular deformation of the groove occurs. For this reason, defects such as welding cracks and angular deformation may not be detected by bead shape sensing immediately after welding.

The present invention has been made in view of the above points, and an object of the present invention is to provide an automatic welding apparatus capable of satisfactorily detecting a defect in a welding bead.

[0011]

In order to achieve the above object, the present invention proposes the following automatic welding apparatus.

That is, the automatic welding apparatus of the present invention includes a welding power source, a welding torch, a traveling carriage that drives the welding torch three-dimensionally, an up-down axis drive mechanism, and a left-right axis drive mechanism.
Welding having a groove position detection sensor for detecting a groove position and a defect detection sensor for detecting a defect of a welding bead, and performing welding line tracing control of a welding torch based on information of the groove position detection sensor In an automatic welding device that performs a defect detection operation that detects and displays a defect in the welding bead based on the operation and the information of the defect detection sensor, a control device that performs the welding operation and the defect detection operation in time division is provided. It is characterized by that.

Further, in the automatic welding apparatus, the control device is a control device for performing a defect detection operation by moving a traveling carriage in a direction opposite to a traveling direction during welding.

[0014]

Since the control apparatus of the present invention executes the welding operation and the defect detection operation by dividing them in time, it is possible to detect the defect at a desired distance interval. Further, since the welding light does not influence the defect detection, it is possible to detect the defect with high reliability. Further, since the defect detection is performed after the welding is completed, it is possible to surely detect the defect such as the welding crack.

Further, if the defect detection is performed when the traveling carriage is returned to its original position after the welding, the throughput of the welding and the defect detection can be improved.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 and 2 are views showing the construction of an embodiment of the automatic welding apparatus of the present invention, FIG. 1 is a bird's-eye view of the automatic welding apparatus of the present invention, and FIG. 2 shows the construction of the control panel 11. It is a block diagram shown.

In FIG. 1, 1 is a material to be welded, 2 is a rail installed on the material 1 to be welded, and 3 is a traveling carriage attached to a rail 2. 4 is a welding torch, 5 is a horizontal axis drive mechanism, and the welding torch 4 is moved in the left-right direction (longitudinal direction of the pipe).
Drive to. 6 is a vertical axis drive mechanism, and a welding torch 4
Drive vertically (in the radial direction of the pipe). The vertical axis drive mechanism 6 is installed on the traveling carriage 3. Reference numeral 7 denotes a groove position detecting sensor, which detects the groove position in a pair with the groove position calculating device 14, and is disclosed in, for example, Japanese Patent Laid-Open No. 4-8310.
The optical disconnection type sensor described in 5 and the like.

Reference numeral 8 denotes a defect detection sensor, which is paired with the defect detection arithmetic unit 15 to detect welding defects such as weld cracks and open blowholes from the bead shape after welding.
For example, it is a CCD camera or a light-section type sensor. The groove detection sensor 7 and the defect detection sensor 8 are installed in the vertical axis drive mechanism 6 as in the horizontal axis drive mechanism 5.
A welding wire 9 is supplied to the vicinity of the welding torch 4 by a wire driving device (not shown). A welding power source 10 and a control panel 11 control the traveling carriage 3, the vertical axis drive mechanism 6, the horizontal axis drive mechanism 5, and the welding power source 10 based on the information from the groove position detection sensor 7 and the defect detection sensor 8. ,
Automatically welds and automatically inspects for welding defects. Reference numeral 101 is a wiring connecting the control panel 11 and the traveling carriage 3 and the like, and 102 is a wiring connecting the welding power source 10 and the welding torch 4.

FIG. 2 shows the structure of the control panel 11.

In FIG. 2, reference numeral 12 is an operation panel for inputting welding conditions such as a groove shape and defect detection conditions. Reference numeral 13 denotes a path plan calculation device, which calculates target values such as a welding torch position and a welding current for each welding pass of multi-layer welding based on given welding conditions. 14 is a groove position calculation device,
Reference numeral 15 denotes a defect detection calculation device for calculating the groove position based on the information of the groove position sensor 7, and the defect detection sensor 8
Process information to investigate the presence of welding defects. Reference numeral 16 denotes a torch drive device that controls the traveling carriage 3, the left-right shaft drive mechanism 5, and the vertical shaft drive mechanism 6, and positions the welding torch 4 based on the speed or position command value from the overall control device 17. To do. Reference numeral 18 denotes a shield gas / cooling water control device for monitoring and controlling the shield gas flow rate and the cooling water amount, and outputs signals to a shield gas and cooling water valve (not shown).

Reference numeral 19 denotes a display device for displaying the arc voltage, arc current, welding position and the like during automatic welding and the presence or absence of welding defects.

Next, an embodiment of the operation of the present invention will be described with reference to FIG.

The processing procedure of FIG. 3 is the processing content of the integrated control device 17.

First, in step 20, welding conditions such as groove shape and welding current and defect detection conditions such as defect detection intervals are input from the operation panel 12. Next, in step 21, the groove shape and welding conditions are sent to the path plan calculation device 13, a command to start calculation of the path plan is issued, and the process waits until the calculation is completed. As an example of the path plan calculation, Japanese Patent Publication No. 4-29473
There is.

When the calculation of the path plan is completed, the procedure proceeds to step 22, and the path plan calculation result is fetched from the path plan calculation device 13 and stored. In the storage device,
For example, the target speed value of the traveling carriage 3 and the welding torch position and the target value of the welding current corresponding to the position of the traveling carriage 3 are stored for each welding pass.

Next, in step 23, the pendant switch (not shown) operates the horizontal axis drive mechanism 5 and the vertical axis drive mechanism 6 to position the welding torch 4 at the center of the groove and set its position to the initial position (zero). And the detected value in the left-right direction of the groove position at that time is set as the initial value. The target value of the welding torch position obtained by the path plan calculation is a value with the initial position set to zero.

When the initial setting of the groove position and the welding torch position is completed, the process proceeds to step 24, the welding pass number is set to 1, and the welding operation step 25 and the defect detection operation step 26 are executed. After the execution, in step 27, it is investigated whether or not the welding and the defect detection operation for all passes are completed. Since the first time is of course not completed, the welding pass number is counted up in step 28, and the process proceeds to step 25. And
When the steps 25 to 28 are repeated and the welding of all the paths obtained by the path plan calculation and the defect detection are completed, the welding of the workpiece 1 and the defect inspection are completed.

Next, the processing contents of the procedure 25 of the welding operation will be described in detail with reference to FIG.

First, in step 40, the traveling vehicle 3 is started to move forward at a set speed. Next, in step 41, the position of the traveling vehicle 3 is fetched, and the target value of the welding torch position and the target value of the welding current corresponding to the traveling position are fetched from the storage device. Next, in step 43, the deviation amount of the groove position, which is the difference between the initial value of the groove position and the current detected value, is fetched from the groove position calculation device 14. Then, in step 44, the target value of the welding torch position and the deviation amount of the groove position are added, and the calculation result is used as the command value of the welding torch position. And step 45
Then, the welding torch position command value is output to the torch drive device 16. As a result, the welding torch 4 is positioned at the optimum position for good welding.

Next, in step 46, the target value of the welding current is output to the welding power source 10. The welding power source 10 controls the welding current so as to match the target value.

Then, in step 47, it is investigated whether or not the position of the traveling carriage 3 has reached the welding end position, and if it has not reached the end position, the process returns to step 41. And step 4
When the traveling carriage 3 reaches the welding end position by repeating steps 1 to 47, the process proceeds to step 48, the traveling carriage 3 stops, and the welding operation ends.

Next, the processing contents of the procedure 26 of the defect detection operation will be described in detail with reference to FIG.

First, in step 50, the traveling carriage 3 is advanced a predetermined distance in the direction opposite to the traveling direction during welding. Next, in step 51, the defect detection calculation device 15 is instructed to start defect detection. Then, in step 52, it is investigated whether or not the defect detection is completed,
When the defect detection is completed, in step 53, the position, type, size, etc. of the defect are fetched from the defect detection calculation device 15,
Remember. The position of the defect is determined by the defect detection calculation device 15
It is set as a value obtained by adding the position of the defect to the position of the traveling vehicle 3 and stored as an absolute position.

Then, in step 54, it is investigated whether or not the traveling vehicle 3 has reached the defect detection end position. Since the first time is of course not completed, the process returns to step 50 and the traveling carriage 3 is restarted.
For a certain distance to detect defects. In this way, after repeating steps 50 to 54, if the position of the traveling vehicle 3 reaches the defect detection end position, the process moves to step 55, and if there is no defect, the display device 19 displays that there is no defect. If there is a defect, the position, type, size, etc. of the defect are displayed on the display device 19, and the operator performs processing for the defect, such as repair.

By thus configuring the defect detection operation, it is possible to detect defects at desired distance intervals. In welding the pipe, the wiring 101 of FIG.
Since there is 102, it is always necessary to return the traveling carriage 3 to the original position after performing the welding operation. Therefore, since the defect detection operation is performed when the traveling carriage 3 returns to the original position, the throughput of welding and defect detection can be improved.

Although FIG. 1 shows an example of piping as the material to be welded 1, even if the material to be welded 1 is a flat plate, the traveling carriage 3 may return to its original position after one pass. If so, it is clear that it does not depart from the gist of the present invention.

Further, in the welding operation of FIG. 4, a value obtained by adding the target value of the welding torch position and the deviation amount of the groove position is set as the command value of the welding torch position. That is, although the groove position is detected in the vicinity of the welding torch 4, the welding position is detected.
The deviation amount of the groove position is detected and stored in front of the tip 4,
When the welding torch reaches the detection position, the welding torch position is corrected by the stored detection value. It is obvious that the same effect can be obtained by using the so-called delayed scanning control.

Further, in the defect detection operation of FIG.
After advancing the traveling carriage 3 for a certain distance and stopping the traveling carriage 3,
Although it has been described that the defect detection is performed, the defect detection may be performed while the traveling carriage 3 is traveling at a constant speed by obtaining a speed at which the defect detection can be performed at a desired interval.

Also, in one embodiment of the operation of FIG.
For each welding pass, the defect detection operation is performed when the traveling carriage 3 returns to the original state after the welding is completed. However, the welding operation and the defect detection operation are temporally divided. It is not out of the gist of the present invention to configure "the defect detection operation with the traveling carriage 3 in the same traveling direction as welding".

According to the present invention, since the welding operation and the defect detecting operation are temporally divided, it is possible to detect the defect at a desired distance interval.

Further, since the welding light does not affect the defect detection, it is possible to detect the defect with high reliability.

Further, since the defects are detected after a while after welding, defects such as weld cracks can be surely detected.

If defect detection is performed when the traveling carriage is returned to its original position after welding, the throughput of welding and defect detection can be improved.

[0045]

According to the present invention, since the welding operation and the defect detection operation are divided in time, the welding light does not affect the defect detection, and the defect detection is performed after the welding for a while, so that the reliability is high. Defect detection can be performed.

[Brief description of drawings]

FIG. 1 is a bird's-eye view of an automatic welding apparatus of the present invention.

FIG. 2 is a block diagram showing a configuration of a control panel.

FIG. 3 is a flowchart showing an example of the operation of the present invention.

FIG. 4 is a flowchart showing the processing contents of procedure 25 of the welding operation.

FIG. 5 is a flowchart showing the processing contents of procedure 26 of the defect detection operation of the present invention.

[Explanation of symbols]

1 ... Material to be welded, 3 ... Traveling carriage, 4 ... Welding torch, 5 ... Horizontal axis drive mechanism, 6 ... Vertical axis drive mechanism, 7 ... Groove position detection sensor, 8 ... Defect detection sensor, 10 ... Welding power source , 11 ...
Control panel, 12 ... Operation panel, 14 ... Groove position calculation device, 15
... Defect detection arithmetic unit, 16 ... Torch drive unit, 17 ... Overall control unit, 19 ... Display unit, 25 ... Welding operation procedure,
26 ... Procedure of defect detection operation.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G01N 21/88 A (72) Inventor Mitsuaki Haneda 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Hitate Manufacturing Co., Ltd. Mechanical Research Laboratory (72) Inventor Shoji Imanaga 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture Hiritsu Manufacturing Co., Ltd. Mechanical Research Laboratory (72) Inventor Masahiro Kobayashi 3-1-1 Sachimachi, Hitachi City, Ibaraki Stock Company Hitachi, Ltd., Hitachi Plant (72) Inventor, Takeo Uehara, 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi Plant

Claims (2)

[Claims] 1. A welding power source, a welding torch, a traveling carriage that drives the welding torch three-dimensionally, an up-down axis drive mechanism, a left-right axis drive mechanism, and a groove for detecting a groove position. A position detection sensor and a defect detection sensor for detecting a defect of the welding bead, and a welding operation for performing welding line tracing control of the welding torch based on the information of the groove position detection sensor, and information of the defect detection sensor. An automatic welding apparatus for performing a defect detection operation for detecting and displaying a defect of a welding bead based on the above, and having a control device for executing the welding operation and the defect detection operation by dividing them in time . 2. The automatic welding device according to claim 1, wherein the control device is a control device that moves a traveling carriage in a direction opposite to a traveling direction during welding to execute a defect detection operation.