JPS61229476A - Weld line automatic profiling method - Google Patents

Abstract

PURPOSE:To perform the good automatic welding without any defect by finding the wire extension of consumable electrode from the end of a tip and by deciding the relative position to the welding joint of each electrode. CONSTITUTION:The so-called welding conditions parameter of the welding current and wire feeding speed is detected on each wire 1, 1a, i.e., each electrode. And the wire extension LE, LE' from the end of a tip is found by an operation based on the relational equation existing between the parameters. The difference in each electrode of the wire extension LE, LE' found by the operation and the difference in the set values of mean values are further found and arcs 7, 7a is controlled so as to track to the weld line automatically by adjusting the two-dimensional moving shafts 11, 12 being fixed to the torch with the signal corresponding to this difference as a profiling signal.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automatic weld line tracing method in arc welding using a consumable electrode.

<Prior art> Conventionally, in arc welding using a consumable electrode (hereinafter referred to as a wire), a method has not yet been found for determining the wire protrusion length during welding and tracing the weld line from the change.
When welding materials by wire arc welding, which consists of multiple torches, it is possible to have the welding torch automatically follow the welding line without providing a special tangible detection mechanism near the welding torch. If possible, it would be advantageous from a structural standpoint.

(Problem to be solved by the invention) The present invention has been made in view of the above-mentioned points, and is capable of detecting welding conditions during welding without providing any other tangible detection mechanism near the welding torch in arc welding using a wire. The object of the present invention is to provide an automatic welding line tracing method in which an arc point automatically follows the welding line using parameters.

(Means for Achieving the Object χ In order to achieve the above object, the welding line automatic tracing method according to the present invention is a welding line automatic tracing method of the consumable electrode type arc welding method consisting of a plurality of torches. A means for detecting welding condition parameters such as a welding current and a consumable electrode feeding speed for the electrode, and processing the relational expression between the above parameters with an electrical calculation circuit, to determine the protrusion length of the consumable electrode from the tip end; Furthermore, means for determining the difference between each electrode in the protrusion length of the consumable electrode obtained by the above calculation and the difference from the set value of the average value, and a signal corresponding to the above difference as a tracing signal, the arc automatically traces the welding line. and means for adjusting a moving mechanism provided on the torch so that the torch moves.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram of a welding circuit using an automatic welding line tracing method according to an embodiment of the present invention, and shows a case where the number of wires, that is, the number of electrodes is two.

As shown in the figure, wire 1. la is wire coil 2,
2a, and is fed by an electric motor 3.3a and rollers 4.4a. The electric motors 3 and 3a are connected as A and A' to a control device (not shown) that controls the rotational speed and start/stop of the electric motor 3.3a, respectively.

Each roller 4.4a is provided with an encoder 5.5a, and the wire feeding speed V is detected by the encoder 5.5a coupled to the rotating shaft of the rollers 4,4a.

The above wire 1. The welding arc 7.7a is connected to the wire l fed by the tip 6.6a.

This occurs between the tip of la and the materials to be welded 8, 8a. Each welding power source 9.9a supplies electrical energy to a welding arc 7.7a.

An insulator 10 is provided between the chips 6.8a to hold the chips 6 and 6a in an appropriate relative positional relationship, and this also serves as the two-dimensional movement axis 11 as shown by the dashed line. .12 mechanically coupled. The two-dimensional movement axes 11 and 12 are mounted on a truck (not shown) and move in a direction perpendicular to the plane of the paper.

In addition, a shunt H, 13a for detecting welding current is inserted in the middle of each power supply path from the welding power sources 9, 9a,
Each output is the average value of the welding current machine (average current 1a
) and an effective value circuit 15.1 for detecting the effective value (effective current 1b) of the welding current.
5a. Furthermore.

An F/V (frequency/voltage) circuit 1B that converts the pulse signals of the encoders 5 and 5a into analog signals.

Equipped with lea.

Each of the above analog circuits, that is, the welding electrician's average value circuit 14. The effective value circuit 15 and the F/V circuit 16 are connected to the A/D converter 17, and similarly, the average value circuit 14a, the effective value circuit 15a, and the F/V circuit 18a are connected to the A/D converter 1? a
It is connected to the. The A/D converters 17.about.17a convert the signals of the respective analog circuits 14 to 1B and 14a"18a into digital signals, and their respective outputs are outputted to the digital arithmetic unit 18.

A setting device 19 is connected to the digital calculator 18, and this is a setting device for setting the wire protrusion length setting value H and the scanning sensing gain. In addition.

H and K are tracing signals (ΔD) which will be described later.

This will be explained in detail using the definition formula of (ΔH).

The scanning signals (ΔD) and (ΔH) taken out as digital signals from the digital calculator 18 are sent to the D/A converter 20.
, thereby converting the signal from the digital arithmetic unit 18 into an analog signal.

Controllers 21 and 22 are connected to this D/A converter. As described above, these controllers 21 and 22 adjust the two-dimensional movement axes 11 and 12 that are connected to the insulator 10 as shown by the dashed line in FIG.

That is, the controller 21 is configured to amplify the scanning signal (ΔH) in the height direction of the torch to control the electric motor 23 that drives the moving shaft 11, and the controller 22 is configured to amplify the scanning signal (ΔH) in the height direction of the torch to control the electric motor 23 that drives the moving shaft 11. An electric 4I that drives the moving shaft 12 by amplifying the scanning signal (ΔD) in the direction perpendicular to both the moving direction and the torch height direction! It is designed to control 24.

In addition, in Fig. 1, LH and LE' are each chip 6°Eta.
The distance from the tip of the welding arc 7.7a to the welding arc 7.7a, the so-called wire protrusion length, is shown.

Next, referring also to FIGS. 2 to 5, each wire 1. l
a, that is, welding current for each electrode (average current 1a,
effective current 1e) and wire feeding speed V.

The so-called welding condition parameters are detected, the wire protrusion length from the tip tip is calculated based on the relational expression that exists between the above parameters, and the difference and average value of the wire protrusion length between each electrode calculated by the above calculation are calculated. By calculating the difference from the set value H of 1 and using the signal corresponding to the above difference as a copying signal and adjusting the two-dimensional moving axis 11.12 fixed to the torch, the arc is created and the welding line is automatically traced. The operation to be controlled so as to encourage the user will be explained.

First, encoder 5.5a and F/V circuit 10°18a
The feed rate (V) of the wire is determined by the shunt 13.1
3a and average value circuit 14.14a detect the average value (Ia) of the welding current, and the effective value circuit 15.15a detects the effective value (Ie) of the welding current.

These analog signals are sent to the A/D converter 17゜17a.
The signal is converted into a digital signal by , and then output to the digital arithmetic unit 18 .

Here, the following quantity Ia; average value (average current) of welding current I; e; effective value (effective current) V of welding current I; wire feeding speed LE, I, E'; has a linear relationship.

LE= f 1(Ia, Ie, v)
...(1) This equation (1) is based on "Research on current-controlled arc welding, July 1980, Welding Society of Japan, Welding Method Committee"
required from.

Therefore, the relationship of equation (1) above is programmed into the digital calculator 18, and the wire feed amount (v) and welding voltage I
(Ia, Is), the wire protrusion length LE
is required.

Note that wire 1. The above LH and LH' for each la
Since there is a correspondence relationship with LE, and the above description of LE applies directly to LE', the process of finding LE is exactly the same as the process of finding LE'.

Next, here, the distance between the tip 6 and the workpiece 8 @LE
The number of samples for distance LE' is n, and the number of samples for distance LE' is m
, define the following quantity.

Here, K and H are constants, K determines the scanning gain, and H determines the wire protrusion length.

The state of FIG. 1 shows the case of LE→LE'', that is, the above equation (2) becomes ΔD+O, and there is no need to perform the weld line tracing correction operation.

Next, if the welding torch shifts to the lower plate side as shown in Figure 2, this indicates the case of LE>LE'.
In other words, the equation (2) becomes ΔD>O, and in this case, the signal from the digital arithmetic unit 18 in FIG. Then, move the axis 12 in the upper left direction in the figure until ΔD=-0.
Adjust the position.

On the other hand, when the welding torch is shifted toward the upper plate as shown in FIG. 3, the situation is reversed. That is, in contrast to FIG. 2, FIG. 3 shows the case where LE<LE'.
m In other words, equation (2) becomes ΔD<O, and in this case, the signal is output to the controller 22 via the D/A converter 20, and drives the electric motor 24 until ΔD'-0. The position of the moving shaft 12 is adjusted in the direction.

Further, the control in the height direction of the torch is as follows; FIG. 1 shows that regarding the above equation (3), ΔH"=Ol, that is, the set value H of the wire protrusion length is appropriately set and balanced. Therefore, in this case, no height control is performed.

Next, FIG. 4 shows the wire protrusion length LH for the set value H.
This shows a case where the welding torch becomes too close to the welded material.

In this case, equation (3) becomes, and in this case, the signal (ΔH) from the digital arithmetic unit 18 in FIG.
1 and drives the electric @23 to adjust the position of the moving shaft 11 in the upper right direction in the figure until ΔH*0 is reached.

On the other hand, FIG. 5, contrary to FIG. 4, shows a case where the wire protrusion length becomes larger than the set value H, that is, a case where the welding torch is too far away from the workpiece to be welded. In this case, equation (3) becomes: The signal (ΔH) at this time is output to the controller 20 via the D/A converter 20, and drives the electric motor 23 to
The position of the moving shaft 11 is adjusted in the lower left direction until H~0 is reached.

In this way, by adjusting the two-dimensional moving axes 11 and 12 fixed to the torch using the signals corresponding to ΔD and ΔH in equations (2) and (3) as copying signals, arcing is automatically performed. The welding line can be traced, and even if the welding line and the cart are misaligned, the arc can automatically follow the welding line.

In addition, in the above embodiment, calculation processing such as wire protrusion length LH is performed by a digital calculation unit, but
This is of course possible with an analog computing unit, and although we have shown the case where the number of wires, that is, the number of electrodes, is two, this is not limited to two, and consumable electrodes consisting of multiple torches can also be used. Applicable to type arc welding method.

<Effects of the Invention> As described above, according to the welding line automatic tracing method of the present invention,
Instead of oscillating the welding electrode, multiple electrodes are used, and the welding current and wire feed speed are detected for each electrode, and by processing these with an electrical calculator, the wire protrusion length is calculated. The relative position of each electrode with respect to the welding joint can be determined from this information, and the arc can automatically follow the welding line, so even if the welding machine is roughly set up with respect to the welding line, it can be set automatically without defects. This has effects such as being able to perform welding.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a welding circuit according to an embodiment of the automatic welding line tracing method of the present invention, Fig. 2 and the following are for explaining its operation. Figure 3 shows the case where the welding torch has shifted to the upper plate side, Figure 4 shows the case where the welding torch is too close to the material to be welded, and Figure 5 shows the case where the welding torch is too far away from the material to be welded. It is an explanatory view showing each case. In the drawing, 1, la...consumable electrode (wire), 5.5a...e encoder, 6.8a...chip, 7.7a...welding arc. 8.8a... Material to be welded, 9.9a... Welding power source, lO... Insulator, 11... Movement axis. 12...Movement axis. 13, 13a... Flow divider. 14, 14a... Average value circuit, 15, 15a... Effective value circuit, 1B, 113a---F/V circuit, 18...
Digital calculator, 18... Setting device, 21... Controller, 22... Controller, LE, LE'... Wire protrusion length.

Claims (1)

[Claims] In the welding line automatic tracing method of consumable electrode arc welding method consisting of a plurality of torches, means for detecting welding condition parameters such as welding current and consumable electrode feeding speed for each electrode, and a relational expression existing between the above parameters. means to calculate the protrusion length of the consumable electrode from the tip of the tip by processing it with an electrical calculation circuit, and further calculate the difference between each electrode and the average value of the protrusion length of the consumable electrode obtained by the above calculation from the set value. and a means for adjusting a moving mechanism provided on the torch so that the arc automatically traces the welding line using a signal corresponding to the difference as a copying signal.