JPS6142485A - Automatic multi-layer welding of endless groove - Google Patents

Abstract

PURPOSE:To perform titled welding nicely regardless of the shape of groove by guiding and controlling a welding torch along endless groove form of a work in an approach copy sensor detecting section in the direction of advance and controlling the depth of arc point by arc sensor detecting current of the torch. CONSTITUTION:A torch 2 of an arm 1 that moves in the direction of depth Z and width X of an endless work groove B is led by a hemispherical face 5b of a approach copy sensor 3 detecting section 5 in the direction of advance Q and oscillated and welded in the detection of the apex (b) and bottom point (a) of one side of the groove B and high position point (c) of another end. Height of the torch 2 is controlled by detection current of an arc sensor 4 of the torch 2. The torch 2 makes automatic multi-layer welding of endless groove B nicely whether the shape is V-shape or shape by related control of an arm 1 operating mechanism and detecting mechanism of the copy sensor 3. Accordingly, automatic welding is made efficient eliminating former teaching of locus of weld line and exchange of detecting section 5.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention automatically performs continuous multi-layer welding on an endless circular or V-shaped groove using an automatic welding machine equipped with an arc sensor and a tracing sensor. This invention relates to an automatic multi-layer welding method for endless grooves.

(Prior art) A method for automatically performing circumferential welding of round workpieces, such as welding where cylinders butt each other or welding where a flange is joined to the end of a cylinder, involves moving the round workpiece using a positioner, In many cases, the welding torch was installed on a rotating jig such as a turning roll, and the welding torch was fixed to a torch stand or the like.

By the way, in order to deal with misalignment of the welding position due to poor machining accuracy of the workpiece, thermal distortion during welding, or poor setting to the rotating jig, the level of automation includes centering before welding starts. The operator corrects the torch position while monitoring the arc point each time.

■The arm that supports the welding torch can be moved three-dimensionally in the depth, width, and longitudinal directions of the groove, so that the welding latch itself can follow the actual welding line as the workpiece rotates. Make the welding torch follow.

Welding is performed using a welding robot j that has a 0 sensor function.

Various methods have been adopted.

(Problem to be solved by the invention) Among these methods, the method [B], in which the worker leaves the groove in place without cutting, is out of the question; (b) It is necessary to use different tip contacts depending on the shape of the groove, such as a sample shape or a V shape, which is imitated by a type of contact sensor.
For the same reason as in the previous item (a), it is absolutely impossible to automatically perform multi-layer welding of a 1V plate from the first layer in the groove to the extra welding, and it is impossible to automatically adjust the welding conditions and torch angle for each layer. It is extremely difficult to change the control. (0) In order to perform even more efficient welding,
Although a pendulum-type weaving device is sometimes used, there are problems such as the inability to detect changes in the groove width and change the weaving width, making it unsuitable for workpieces with poor machining accuracy. there were.

On the other hand, in method ◎, (a) current welding robots basically use a teaching/playback method, so the total length of the welding line must be taught in advance, making it difficult to produce high-mix, low-volume production. (b) "Contact type sensor""Arcsensor" can correct the trajectory of the weld line taught as described in item (a). However, the degree of deviation that can be corrected is limited, and when using an arc sensor, weaving is an essential operation, so if there is a workpiece that cannot be weaved for some reason, it cannot be applied. There were many problems.

Also, as is common to all of the above methods, when a pair of cylinders are butted together and then welded, flanges are welded to both ends of the cylinder using turning rolls, etc. , there are two types of flange shapes, right-handed and left-handed, and a v-shaped bevel in the center, and both require multilayer stacking, and although the machining accuracy of the workpiece is sufficient, There is also the problem that tanning roll work involves the movement of the workpiece and the welding line is constantly changing, and the reality is that automation cannot be achieved with each method. there were.

In order to deal with these problems, the present invention uses a special tracing sensor and also uses this tracing sensor and an arc sensor in combination to select the detection signals from both sensors depending on the shape of the groove. By overcoming the above-mentioned problems,
The purpose is to make automatic multi-layer welding possible regardless of the V-shape, thereby further promoting highly accurate and highly efficient unmanned welding.

(Means for Solving the Problems) Therefore, the present invention makes it possible to move two-dimensionally in the depth direction and the width direction of the groove (B) of the endless workpiece 11A9, which is illustrated in the drawings. The welding torch (2) is attached to the tip of the arm (1) of the welding machine, and the detecting part (5) having a hemispherical surface (5b) at the tip of the cylindrical surface (5a) detects 01
1. A tracing sensor (3) capable of detecting an upright wall extending in the depth direction of the groove (B) on the cylindrical surface (5a) and the bottom of the groove (2) on the hemispherical surface (5b). , said welding 1--chi (2
) and supported by the OII arm (1), and an arc sensor (4) for detecting welding current is provided in association with the welding torch (2), Move the welding torch (2) to the welding starting point of the groove (B), and mark the apex @, the bottom point [A] on one side of the groove (B) K, and the apex or final welding point on the other side. The arc point is positioned so that it matches the high position @, and the three points at that time are read into the storage unit of the control device as reference values, and the The depth direction position of the arc point is determined by the arc sensor (4).
) is carried out by moving the arm (1) so that the detected current matches a predetermined value, and in the case of a tapered groove), the detection current is moved from the bottom point [a] to the high position @. The width direction position on the upright wall side of the range is detected by the tracing sensor (3), and the width direction position on the inclined wall side of the range from the bottom point [A] to the apex @ is detected by the arc sensor (4). On the other hand, if the groove () is V-shaped, the widthwise position of the bottom point [A] is detected by the tracing sensor (3) only for first layer straight welding, and the [1] The force direction position is detected by the arc sensor (4) based on the change in current increase. This method is characterized by a multilayer welding method that automatically performs welding.

(Function) By having such a means, the present invention has the following features:
Regardless of the shape of the V-shaped groove, the three welding starting points ■, @
, O, there is no need to teach the trajectory of the welding line, and the rest is welding 1 according to the command signals from the arc sensor and copying sensor.
--It is possible to perform continuous multi-layer welding automatically by simply moving the tip, and it handles simple setting changes (switching commands between square and V shapes) and three-point teaching. The operator only needs to operate it first.

(Embodiments) Hereinafter, embodiments of the present invention will be described based on the accompanying drawings FIGS. 1 to 5.

FIG. 1 is a schematic diagram of a welding apparatus according to the present invention, in which (1) shows an endless bevel of a round workpiece (W) mounted on a turning roller (8) by an arm of a welding machine. (B)
, in the depth direction (in the illustrated example, the vertical direction, which is referred to as the two axes) and the width direction (also in the horizontal direction, which is referred to as the two axes).
2 axes (referred to as ``ro axis'') and 2 axes (ro axis,
However, since it is movable in three axes (manual operation) and has a degree of freedom of three-dimensional multidimensional movement, it is a basic structure equipped in a known welding device, so the details will be omitted.

A welding torch (2) is attached to the tip of this arm (1) so that its swing angle in the vertical plane can be controlled, but this swing angle control (this is called the S axis) has also been conventionally performed. It is a means of

In the illustrated example, the round workpiece W mounted on the turning roller (8) is rotated and the bevel (B) is rotated.
Since the groove (B) moves relative to the welding line direction between the welding torch (2) and the welding torch (2), the welding equipment has
, S should be controlled, but for example, when a cylinder is erected on a flat plate and the joint is welded, the welding of the groove (B) to the arm (1) is sufficient. It is naturally necessary to add a linearly movable movement mechanism.

An arc sensor (4) for detecting welding current is attached to the tip of the welding torch (2), and the arm (1)
A copying sensor (3) is supported at the tip of the welding torch (2), and the detecting portion (5) of the sensor (3) is disposed in front of and close to the arc point of the welding torch (2).

The structure of the copying sensor (3) is shown in Figure 2, and the movement of the detection part (5) is transmitted as the rotational movement of a contact of a potentiometer inside the sensor body, and the mechanical displacement is converted into a change in voltage. It is formed into a so-called analog type sensor that can be read.

The detection part (5) is fixed to the tip of a lever (7) fixed to a rotating shaft provided in relation to a potentiometer in the main body (6), and It has a round bar shape with a hemispherical surface (5b) integrally formed at the tip (lower end).

The copying sensor (3) having a detecting part (5) as shown in FIG. At the same time, the lever (7) is provided so as to be slidable up and down while being pushed vertically downward by a spring force.

The cylindrical surface (5a) detects the upright wall extending in the depth direction of the groove (in other words, the vertical wall in the diamond-shaped groove), while the hemispherical surface (5b) at the tip detects the vertical wall extending in the depth direction of the groove. The bottom of the groove (B) can be detected.

Note that the detection of the bottom of the groove (B) by the hemispherical surface (5b) is not done by directly touching the bottom, but by detecting the bottom from the bottom by touching two walls extending on both sides. This can be indirectly detected by assuming that the bottom is a point that has fallen a few millimeters.

Next, a method of welding according to the present invention on the water side will be explained with reference to FIG.

■In the case of a flange-shaped groove (B), welding is performed in multiple layers using the panu-weaving method, one layer at a time. The shape of the multi-layer stack is taught at three points: ■ and 0°θ.

In this case, the three points are the apex on one side of the groove (B), that is, the apex on the sloped wall side, the bottom point [A], and the high position point that corresponds to the final welding point on the upright wall. There are three locations.

Copying sensor (3) Clamp lever (9) for fully fixing
), and lift the sensor body (6) all the way upwards, so that the cylindrical surface (5a) of the detection part (5) comes into contact with the flange surface of the workpiece W due to the spring pressure, and is stabilized near the rotational neutral position. After that, tighten and fix the clamp lever (9) (see Fig. 4).

In this way, the flange surface is detected by the copying sensor (3), and changes in the vertical direction and during the beveling are detected by the arc sensor (4).
) is detected as a change in current increase, and welding is performed from the first layer of the groove to the final layer of reinforcement using preset current (voltage), speed, torch angle, and weaving conditions.

That is, the shape of each point () of the groove is detected by the arc sensor (4), and the weaving width is expanded for each layer.

Then, in the reinforcement section, the weaving width is narrowed while subtracting the preset reinforcement reduction width for each layer from the X value of the previous layer, and when the height of point O is reached, the weaving width becomes B.
Welding is completed when it becomes less than mm.

In the control device of the welding equipment, each layer, that is, the workpiece
Equipped with a memory that records the position (X, Z) of the tip of the welding torch (2) corresponding to the circumferential position of the workpiece W (taught at an angle of 0) for each lap, and Data is updated sequentially from layer to record one round.

From a welding perspective, for the final layer of extra welding, it is desirable to tilt the torch angle to ensure sufficient penetration, but in this case, the vertical tracing by the arc sensor (4) becomes unstable, so A constant value of 2 is added to the value of θ→2 recorded in the previous layer to perform vertical control and welding.

In addition, the point on the flange side when weaving and straightening
- The upright wall surface marked with 〇 is always detected by the tracing sensor (3). As a result, even if the flange surface moves due to walking of the workpiece, the welding torch always follows and stable welding is possible.

■For butt part V-shaped groove (B) The welding method and teaching method are the same as those for the chopper groove.

However, the three teaching points in this case are the apex [B] on one side of the groove (B), the bottom point [A] on the opposite side, and the apex O of the inclined wall on the opposite side.

Loosen the clamp lever (9) of the copying sensor (3) to lower the sensor body (6), and place the copying sensor so that the arc point and the tip of the detection part (5) approximately match with the welding line. (3), and use the spring force to position the detection part (
5) is lightly pressed against the groove (B) and then tighten the clamp lever (9) (see Fig. 5).

In the illustrated example of the workpiece W, weaving may be performed on the inner first layer of the groove so that the arc sensor (4) may not be able to detect the weld line.

This is because, in the case of a groove (B) without a backing plate, the current is lowered and straight welding is sometimes performed to prevent melt from dripping.

Therefore, in this case, the tracing sensor (3) is set inside the groove (E), and the weld line is traced by this displacement.

However, if the workpiece can be weaved, it goes without saying that weaving can be performed from the first layer.

For the second and subsequent layers, the arc sensor (4) performs z-axis positioning and detection of the groove (B).

The detection part of the copying sensor (3) set in the groove (B) in the first layer may be set at that position, but the detection part of the copying sensor (3) set in the groove (B) in the first layer may be set slightly before one round of the program ball (corresponding to the distance that the copying sensor (3) is leading). ), if the information from the copying sensor (3) is ignored, there will be no inconvenience if the detection part (5) gets on the bead in the second layer and comes off from the inside of the groove. does not occur.

Because the arc sensor (4) cannot detect the groove (B) in the extra layer, the memorized value of θ → Perform welding. Of course, if there is an extreme movement of the workpiece W during this time, this cannot be handled, but by making the excess weaving width wider, a very satisfactory welding result can be obtained.

Table 1 below summarizes the above welding methods.

(Effects of the Invention) The present invention has the configuration and operation described above, and has a tracing sensor (3) capable of detecting the vertical wall and bottom of the groove (B).
) and an arc sensor (4), the setting of the tracing sensor can be changed with a single lever operation even on workpieces with a mixture of rectangular and v-shaped shapes. Automatic multi-layer welding can be performed without the labor and time-consuming steps such as replacing parts.

In addition, by using the copying sensor (3) and the arc sensor (4) together, the weak points of each can be compensated for and the shape, V
Straight welding and weaving welding can be performed in a wide current range for both shapes.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an example of a welding device according to an embodiment of the present invention, Fig. 2 is a perspective view of the copying sensor in Fig. 1, Fig. 3 is a perspective view of the vicinity of the welding torch, and Fig. 4 (A). ,(
B) A plan view and a front view showing the positional relationship between the welding torch and the copying sensor in the case of a chopper-shaped groove, Figures 5 (a) and (b) are the welding torch and the copying sensor in the case of a V-shaped groove. FIG. 6 is a plan view, a front view, and a sectional view of FIGS. (1)...Arm, (2)...Welding l
・-chi, (3)...copying sensor, (4)...arc sensor, (5)...detection section, (5a)・
... Cylindrical surface, (5b) ... Hemispherical surface, (i')
...Bottom point, 0...Apex, ◎...High position point, )...Bevel, W...Work. Figure 1 Figure 2 Figure 3 Figure 4 ←) Figure 4 (B)) Figure 5 (A) Figure 5 (B)

Claims (1)

[Claims] 1. The depth direction of the groove (B) of the endless workpiece (W),
Welding machine arm that can move two-dimensionally in the width direction (1
) Attach the welding torch (2) to the tip of the cylindrical surface (5a).
The detection unit (5) having a hemispherical surface (5b) at the tip of the cylindrical surface (5a) detects an upright wall extending in the depth direction of the groove (B) using the hemispherical surface (5b). A tracing sensor (3) capable of detecting the bottom of the groove (B) is attached to the welding torch (2).
) and supported by the arm (1), and an arc sensor (4) for detecting welding current is provided in association with the welding torch (2), Move the torch (2) to the welding starting point of the groove (2), and mark the apex [B] on one side of the groove (B), the bottom point [A], and the apex or final welding point on the other side. The arc point is positioned so that it matches the high position point [c], and the three points at that time are read into the storage unit of the control device as reference values, and the inside of the groove (B) and the first layer of excess are read. The depth direction position of the arc point in the section is determined by the arc sensor (4).
) by moving the arm (1) so that the detected current of The position in the width direction on the upright wall side in the range of point [C] is determined by the scanning sensor (3).
At the same time, the width direction position on the inclined wall side in the range from the bottom point [a] to the apex [b] is detected by the arc sensor (4).
When the groove (B) is V-shaped, the position in the width direction of the bottom point [A] is detected by the above-mentioned scanning sensor (3) only for first layer straight welding. The positions in the width direction are all detected by the change in current increase using the arc sensor (4), and each welding of the first layer straight in the groove, the first layer weaving in the groove, the weaving in the groove, and the additional first layer weaving can be performed. An automatic multi-layer welding method for endless grooves, which is characterized in that it is performed automatically.