JPH06277843A - Method and device for multilayer welding - Google Patents

Abstract

PURPOSE:To accurately perform an automatic welding without forming welding defects. CONSTITUTION:A pair of non-welding sensors 27a, 27b, which are arranged side by side in the direction, orthogonal to a welding joint, are moved along the welding joint 30 by the hand 25 of a robot 21, and the sectional forms of the welding joint 30 are measured. Among the sectional forms of the welding joint 30, on the line which is made with the deepest position connected along the welding joint, a welding torch 26 is moved by means of the hand 25. By this welding torch 26, the layer of beads 20 is formed in the welding joint 30, and thereby multilayer welding is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a welded joint portion (groove portion).
TECHNICAL FIELD The present invention relates to a multi-layer welding method and multi-layer welding apparatus for multi-layer welding.

[0002]

2. Description of the Related Art A conventional multi-layer welding apparatus is shown in FIG. Figure 8
As shown in FIG. 1, the conventional welding apparatus includes a robot 21, a robot controller 42, and a welding power source 43. Further, the robot 21 has a welding torch 26 and a hand section 25 for holding a contact type sensor 27 which is separated by several centimeters. This sensor 27 is capable of detecting biaxial displacement positions of up and down and left and right.
The groove portion 30 to contact the hand portion 25 of the robot 21.
By moving, the sensor 27 follows the groove portion 30 to detect the displacement amount (movement amount) of the sensor 27. Further, this displacement amount is determined by the robot controller 42 as position data of the welding torch 26, and the welding torch 26 is positioned and welded to the groove portion 30.

At the time of welding the first layer, the sensor 27 detects the position of the deepest groove of the groove 30 in front of the welding torch 26 and uses this as position data of the welding torch 26. However, from the second layer, since the groove is filled with the weld bead 20, the position cannot be detected by the sensor 27. That is, for the second and subsequent layers, the number of layers for multi-layer welding and the welding order of the layers are programmed into the robot controller 32 according to the drawing of the groove portion based on the position data when the first layer is welded. Thus, the position data of the welding torch 26 is determined, and the multi-layer welding is performed.

[0004]

In the welding method as described above, since the position data of the first layer is used as the position data of the subsequent multi-layer welding, the shape of the groove portion is affected by the heat of welding during welding. May be deformed and welding may not be performed accurately. Further, since the light-opening process is generally performed by a grinder, if there is an error of several millimeters, it may not be possible to perform welding accurately according to the drawing dimensions. If the above-described problems are ignored and the number of layers and the order are programmed into the robot controller 2 in advance and automatic welding is performed, the number of layers is too large, beads are overflowed from the light opening portion 30, or the order of layers is not appropriate. Sometimes. For this reason,
There is a problem that good automatic welding cannot be performed. In this case, in order to fill these drawbacks, it is necessary to take measures to stop welding and change the program so that human monitoring is required and the above-mentioned problems do not occur during welding.

The present invention has been made in view of the above points, and an object of the present invention is to provide a multilayer welding method and a multilayer welding apparatus capable of performing multi-layer welding with high accuracy.

[0006]

According to the present invention, a pair of non-contact sensors arranged side by side in a direction orthogonal to a welded joint portion is moved along the welded joint portion and each cross section of the welded joint portion is moved. Forming a bead layer on the weld joint by moving the welding torch to the line that connects the deepest position along the weld joint among the measured shape and the cross-sectional shape of the weld joint. And a step of measuring the cross-sectional shape and a bead layer forming step are sequentially repeated to form a multi-layered bead on the welded joint portion, and a method for orthogonally welding the welded joint portion. Arranged side by side in a direction, a pair of non-contact sensors for measuring the cross-sectional shape of the welding joint portion, and a sensor drive mechanism for moving the pair of non-contact sensors along the welding joint portion,
A welding torch that forms a bead layer on the weld joint, a torch drive mechanism that moves the weld torch along the weld joint, and each cross-sectional shape of the weld joint based on the data from the pair of non-contact sensors. And a control device for controlling the torch drive mechanism so that the welding torch passes on a line connecting the deepest position of the cross-sectional shape along the welded joint portion, and the welded joint portion is provided. A multi-layer welding device for forming multi-layer beads.

[0007]

According to the present invention, by moving a pair of non-contact sensors arranged side by side in a direction orthogonal to the welded joint portion along the welded joint portion, among the cross-sectional shapes of the welded joint portion, For example, one slope portion can be detected by one non-contact sensor, and the other slope portion can be detected by the other non-contact sensor. Therefore, the entire cross-sectional shape of the welded joint can be accurately measured. Also, among the measured cross-sectional shapes of the welded joint, by moving the welding torch in a line shape connecting the deepest positions to form the bead layer, the most recessed part of the cross-sectional shape is selected. It is possible to carry out multi-layer welding, and the surface of the weld bead of each layer can be made smooth as a whole. Further, no deep dent is generated in the weld bead, and welding defects can be eliminated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 are views showing an embodiment of a multilayer welding method and a multilayer welding apparatus according to the present invention. Figure 1
Further, in FIG. 2, reference numeral 21 is a robot, and the robot 21 has a hand portion 25, and the hand portion 25 holds a welding torch 26 for forming the welding bead 20. The hand portion 25 and the welding torch 26 are connected to the robot controller 22 and the welding power source by a cable 34, respectively. Furthermore, the robot controller 22
Is connected to the personal computer 24 by a cable 34. In the hand unit 25 provided at the tip of the robot 1,
Adjacent to the welding torch 26, a welded joint portion (groove portion) 30
A pair of optical sensors 27a and 27b are held. The pair of optical sensors 27a and 27b are respectively provided on one side and the other side of the vertical surface T along the groove portion 30, respectively, and are perpendicular to the light beam from the pair of optical sensors 27a and 27b to the groove portion 30. The angles with the plane T are each 15 ° (FIG. 5).

As shown in FIG. 5, the pair of optical sensors 27a and 27b held by the hand portion 25 are provided on the hand portion 25 above the base material 28 which is the object to be welded of the groove portion 30. Fine adjustment is performed by the vertical movement motor 31 and the horizontal movement motor 32. Also, a pair of optical sensors 27a and 27b
Is designed to measure the cross-sectional shape of the groove portion 30 during welding. That is, the pair of optical sensors 27a, 27
The measurement data from b is sent from the robot controller 22 to the personal computer 24 and data processing is performed to obtain the cross-sectional shape. Then, in the personal computer 24, information on the deepest position of the cross-sectional shape and the welding cross-sectional area of the portion to be welded is obtained. Next, the deepest position and the welding cross-sectional area are sent from the personal computer 24 to the robot controller 22, and the robot controller 22 positions the welding torch 26 held by the hand portion 25.

The hand unit 25 includes a pair of optical sensors 27.
It functions as a drive mechanism for both the a and 27b and the welding torch 26. In addition, the robot controller 22 and the personal computer 2
The robot controller 22 moves the hand part 25 along the groove part 30. Robot controller 2
The vertical movement motor 31 and the horizontal movement motor 32 are driven by 2, and the pair of optical sensors 27a and 27b are finely adjusted.

As described above, the cross-sectional shape of the groove portion 30 is a laser beam from the pair of optical sensors 27a and 27b, which are arranged to be symmetrical with respect to the vertical plane T by 15 °, to the base material 28 of the groove portion 30. It is obtained by projecting light and measuring the distance based on the reflected light using a triangulation method. If the surface of the base material 28 is a glossy surface and the projection angle between the laser light and the base material is small, the amount of reflected light returning to the pair of optical sensors 27a and 27b is small, and erroneous measurement or measurement is impossible. There is.

In the case of the present invention, as shown in FIGS. 5 and 6, a pair of sensors 27a and 27b project and receive laser light from angles symmetrical to each other to receive a laser beam, so that the groove portion in which the light amount is particularly insufficient. 30 slopes or weld beads 2
The unevenness of 0 can be accurately measured. That is, for example, one optical sensor 27a measures the distance to one slope of the groove portion 30 where the projection angle of the laser light is large (the amount of reflected light is large), and the other optical sensor 27b projects the laser light. Measure the distance to the other slope where the light angle is large. Then, the images 35a and 35b obtained by the pair of optical sensors 27a and 27b are transferred to the robot controller 2
Each image is input to the personal computer 24 via 2, and the images obtained by the personal computer 24 in two directions are combined. In this way, the cross-sectional shape of the groove portion 30 can be accurately measured.

Next, the pair of optical sensors 27a and 27b will be described in detail.

As shown in FIG. 5, this pair of optical sensors 2
7a and 27b are driven by a vertically moving motor 31 and a horizontally moving motor 32, and a pair of optical sensors 27a and 27b.
The robot controller 22 controls the vertical movement motor 31 and the horizontal movement motor 32 so that the zero reference of b is always the measurement target surface.

Therefore, the measured value of the distance between the pair of optical sensors 27a, 27b and the base material 28 is the amount of movement of the pair of optical sensors 27a, 27b by the vertical movement motor 31. In this way, the pair of optical sensors 27a and 27b and the base material 2
By obtaining the distance between the groove and the groove 8, the shape of the groove portion 30 larger than the measurement range can be accurately measured by using the optical sensors 27a and 27b having the measurement range of several tens mm.

The pair of photosensors 27a and 27b use laser light and the reflected light from the base material 28 to utilize the groove portion 30.
Since the cross-section shape is measured, it is considered that the arc light from the welding torch 26 affects the amount of reflected light of the laser during welding and causes a measurement malfunction.

Therefore, in this embodiment, the groove 30 is formed during welding.
After forming each layer of the welding bead 20 without performing the measurement of
In the step of returning by, the groove portion is measured by the pair of optical sensors 27a and 27b. Next, the sectional shape of the groove portion 30 is obtained by the personal computer 24, and the robot controller 22 stores the sectional shape data. After that, welding is performed using this data at the time of welding.

Next, the operation of this embodiment having such a structure will be described with reference to FIGS. 3, 4 and 7.
FIG. 7 is a flowchart showing the operation of this embodiment.

First, FIGS. 3 and 4 show the order of multi-layer welding in the groove portion 30. As shown in FIGS. 3 and 4, the cross-sectional shape of the groove portion 30 is displayed on the screen of the personal computer 24. The welding torch 26 is moved by the hand 25 to the groove 3
Moving along 0, the first layer 1 of the bead 20 is formed. Next, the groove portion 30 is measured by the pair of optical sensors 27a and 27b, and the personal computer 24 obtains the cross-sectional shape of the groove portion 30. Next, the groove portion 3 is opened by the personal computer 24.
When the depth of the cross-sectional shape of 0 is measured and two deep places are measured at the same time, it is decided to weld the bead 20 having the numeral 2, for example, based on a rule giving priority to the side specified in advance. In this way, the welding torch 26 is moved by the hand portion 25 along the groove portion 30, and the bead 20 is moved.
A second layer 2 of is formed. Next, a pair of optical sensors 27
The groove portion 30 is measured by a and 27b, and the personal computer 24
Thus, a deep position of the cross-sectional shape of the groove portion 30 can be obtained. The welding torch 26 then applies the third layer 3 of the beads 20.
Is formed. Thus, it is always formed by the welding torch 26. The layer of the bead 20 is formed on the line connecting the points at the deepest distance 1 in the cross-sectional shape of each groove 30 along the groove 30.

The fifth to eighth beads 20 are arranged in this order.
After forming the layers 5, 6, 7, and 8, the seventh layer 7 and the eighth layer 8 of the bead 20 are compared with the measurement data of the groove portion 30 to obtain the deepest position. When two deepest positions are detected at the same time (see black circles at the intersections of the fifth layer 5 and the seventh layer 7 and black circles at the intersections of the seventh layer 7 and the eighth layer 8 in FIG. 3), it is close to the base material 28. The ninth layer of the bead 20 is formed based on the side-first rule.

From the cross-sectional shape of the groove portion 30 after each layer of the bead 20 is formed, the deepest distance 1 and the welding cross-sectional area S to be welded are calculated by the personal computer 24 and displayed.

As shown in FIG. 4, the calculation for obtaining the welding cross-sectional area is performed as follows. That is, the groove portion 30
Equal spacing (1 mm pitch in this device) on each cross section
, The depths l ₁ , l ₂ , ... Are connected by a straight line, and the sum of the areas of the enclosed blocks is defined as the welding cross-sectional area S of the groove portion 30 to be welded.

In each cross-sectional shape of the groove, it is judged that the welding is completed when the deepest distance 1 and the welding cross-sectional area S become 0 or a negative value in the entire region, and the above-mentioned multi-layer welding work is completed. To do.

In the case of fillet welding, which is a type of welded joint that is not grooved, the final cross-sectional shape of the multi-layer weld is stored in the robot controller 22 via the personal computer 24 before welding. . Then, the measured value of the cross-sectional shape of the welded joint portion measured each time each layer was welded was compared with the final value stored in advance, and the welding cross-sectional area S or the deepest distance l became 0 or negative. Complete the welding operation at this point.

As described above, according to this embodiment, the pair of optical sensors 27a and 27b are provided symmetrically with respect to the vertical plane T along the groove portion 30, and the pair of optical sensors 27a and 27b are provided.
By combining the distance signals in a state where the amount of reflected laser light from b is high, stable shape measurement can be performed with respect to external light (arc light or sunlight). In addition, since the most recessed portion of the cross-sectional shape of the groove portion 30 is selected for multi-layer welding, the surface of the weld bead in each layer is generally smooth. For this reason, extremely deep dents do not occur in the weld bead, and welding defects (welding defects) that frequently occur during welding in deep dents can be eliminated.

Further, since the cross-sectional shape of the groove portion 30 is constantly measured, even if the cross-sectional area of the groove portion 30 shrinks and becomes small in the middle due to thermal deformation, welding is performed when the welding cross-sectional area is 0 or negative. Since it is completed, the welding bead does not rise as much as the smaller size as in conventional welding,
Stable welding can be performed according to the shape. Further, the pair of optical sensors 27a and 27b are the optical sensors 27a and 2b.
Since the follow-up movement is controlled so that the zero reference of 7b becomes the measurement surface, the optical sensor 27 having a small measurement range (several centimeters) is used.
It is possible to use a and 27b. For example, a high-precision sensor having a measurement precision of 0.1 mm or more generally has a measurement range of several centimeters, but according to the present embodiment, such a high-precision sensor can be used, and a pair of optical sensors 2 can be used.
The measurement by 7a and 27b can be performed when there is no arc light, the influence of the light of the arc light, high frequency noise, etc. can be neglected, and the measurement can be performed with high accuracy without any countermeasures.

Another embodiment will be described below. In the above embodiment, the pair of optical sensors are provided symmetrically at an angle, but the present invention is not limited to this, and it is conceivable to measure the cross-sectional shape of the welded joint from a symmetrical angle using one optical sensor and a mirror. .

Further, in the above embodiment, the cross-sectional shape of the welded joint was detected by the laser beam, but instead of the optical sensor using the laser beam, a pair of TV cameras (CCD cameras) arranged at an inclination is used. It is also possible to detect the deepest position from the image data of the cross-sectional shape of the welded joint thus obtained and use it as the positioning data of the welding torch for welding the next layer.

[0030]

As described above, according to the present invention,
By measuring the cross-sectional shape of the welded joint with a pair of non-welding sensors arranged side by side in a direction orthogonal to the welded joint, the inclined surface and the uneven surface of the welded joint can be accurately measured. The cross-sectional shape can be obtained.
In addition, since the bead layer is formed along the line connecting the deepest positions of the cross-sectional shape of the welded joint portion, it is possible to perform accurate automatic welding without welding defects.

[Brief description of drawings]

FIG. 1 is an overall system diagram showing a multilayer welding method and a multilayer welding apparatus according to the present invention.

FIG. 2 is an enlarged perspective view of a hand unit of the robot.

FIG. 3 is a view showing a sectional shape of a welded joint portion.

FIG. 4 is an explanatory diagram for obtaining a welding cross-sectional area from a cross-sectional shape of a welded joint portion.

FIG. 5 is a diagram showing a state in which a cross-sectional shape of a welded joint portion is measured by an optical sensor.

FIG. 6 is a diagram showing a state in which a cross-sectional shape of a welded joint portion is obtained based on a signal from an optical sensor.

FIG. 7 is a flowchart showing the operation of the present invention.

FIG. 8 is an overall system diagram showing a conventional multi-layer welding method and multi-layer welding device.

FIG. 9 is an enlarged perspective view of a hand unit of the robot.

[Explanation of symbols]

 20 bead 21 robot 22 robot controller 24 personal computer 25 hand part 26 welding torch 27a, 27b optical sensor 28 base metal 30 weld joint part (groove part)

Claims (3)

[Claims] 1. A step of moving a pair of non-contact sensors arranged side by side in a direction orthogonal to a welded joint portion along the welded joint portion to measure a cross-sectional shape of the welded joint portion, and Of each cross-sectional shape of the welded joint part formed, the step of forming a bead layer in the welded joint part by moving the welding torch on the line connecting the deepest position along the welded joint part, A multi-layer welding method characterized in that a multi-layer bead is formed in a welded joint portion by sequentially repeating a cross-sectional shape measuring step and a bead layer forming step. 2. After the step of measuring the cross-sectional shape, the weld cross-sectional area to be welded is obtained from each cross-sectional shape, and when the weld cross-sectional areas along the weld joint are all zero or a negative value,
The multi-layer welding method according to claim 1, further comprising a step of stopping the welding operation. 3. A pair of non-contact sensors, which are arranged side by side in a direction orthogonal to the welded joint, for measuring the cross-sectional shape of the welded joint, and the pair of non-contact sensors are arranged along the welded joint. Based on the data from the pair of non-contact sensors, a sensor drive mechanism that moves the welding torch that forms a bead layer on the weld joint, a torch drive mechanism that moves the welding torch along the weld joint, And a controller for controlling the torch drive mechanism so that the welding torch passes on a line connecting the deepest position of the cross-sectional shape along the weld joint, while obtaining each cross-sectional shape of the weld joint. And a multi-layer welding device for forming a multi-layer bead on a weld joint.