JPH02251374A - Method and equipment for profile welding - Google Patents

Abstract

PURPOSE:To form a welding bead having an excellent shape by varying the melting quantity of a filler wire according to variation of the size of profile motion when an electrode separates and approaches in the profile welding process. CONSTITUTION:In the case of profile motion (c) where the electrode 4 separates from a weld zone 15, a parameter adjustment means 35 is controlled by a controller 33 so that when the variation increases, the melting quantity is decreased and when the variation decreases, the melting quantity is increased. In addition, in the case of profile motion (b) where the electrode 4 approaches a joint, it is controlled so that when the variation increases, the melting quantity is increased and when the variation decreases, the melting quantity is decreased. By this method, the welding bead having the ideal shape can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of Application The present invention is applicable to hot wire welding used in consumable electrode welding such as CO□ welding and MIG welding, or non-consumable electrode welding such as TIG welding. This invention relates to a welding method and device that uses copy welding.

B. Conventional technology The hot wire TIG welding method has been known for a long time (for example, Proceedings of the Welding Society of Japan, Vol. 4 (1986), No. 4 t).
p678-684: ■Welding Society Journal Volume 57 (1988
) No. 6, p457). The hot wire TIG welding method is a method in which an arc is formed between a non-consumable electrode and the part to be welded, and the additive wire 7 is fed into the arc by a motor and heated by electricity, which improves the efficiency of the TIG welding method. This is an attempt to improve quality.

Furthermore, a welding method is also known in which hot wire welding is used in combination with a welding method using a consumable electrode, such as MIG welding method. FIG. 3 schematically shows the structure, and shows a case in which a standing plate 2 is set perpendicularly to the lower plate 1 and both intersection lines are fillet welded.

In FIG. 3, a welding current is supplied from a welding power source 5 to a welding wire (consumable electrode) 4 that is fed through the welding torch 3, and an arc is created between the welding wire 4 and a non-welded part 15. is formed. Additionally, an additive wire 7 is inserted and fed into the arc of the welding wire 4 through the inside of the wire guide 6.
Power is supplied from the additive wire power supply 8 to contribute to bead formation. 9 is a welding arc, 10 is a molten pool, and 11 is a weld bead.

In this type of hot wire welding method, the amount of feed of the additional wire 7 and the amount of power supplied relative to the welding current supplied to the electrode 4 are fixed at preset values before welding, so the welding current fluctuates during welding. This causes the appearance of the weld bead to deteriorate and weld defects to occur.

On the other hand, a copy welding method has been known for some time (for example, Welding Technology August 1985 issue, pages 79-83).

FIGS. 4 and 5 are diagrams for explaining the principle of copy welding using the arc sensor method.

When moving the welding torch 3 along the target welding line 12 shown in FIG. 4, the welding torch 3 is swung in a direction 13 orthogonal to the target welding line 12, and the maximum swing position 42 of the welding torch 3 shown in FIG. 4 is reached. For example, the welding current is monitored. and,
Adjust the center of deflection of the welding torch 3 so that the welding current is equal in both positions (a) and (b), and reset the target welding line passing through the center. Therefore, even if the actual welding line (part to be welded) 15, which is the intersection line between the lower plate 1 and the upright plate 2, is inclined with respect to the target welding line 12 of the welding torch 3, the welding torch 3 is moved along the actual welding line 15. can be driven by following.

C6 Problems to be Solved by the Invention The relationship between the target welding line 12 and the actual welding line is classified as shown in FIGS. 6(a) to 6(c). (a) shows the case where the direction of the target welding line 12 and the direction of the actual welding line 15 match, and (b) shows the actual welding line 1 with respect to the target welding line 12.
5 is approaching, and (Q) is a case where the actual welding line 15 is moving away from the target welding line 12. In the case of (a), an ideal beat shape is obtained as shown in FIG. 7(a).

In the case of (b), when the target weld line 12 goes too far to the vertical plate 2 side during copy welding, it becomes a convex bead shape as shown in Fig. 7(b), and the needle end on the lower plate 1 side tends to overlap. shows. In the case of (Q), if the target welding line 12 is too far away from the standing plate 2, it will become a flat bead shape as shown in FIG. 7 (Q), and the throat thickness will tend to be insufficient. In the conventional copy welding method, bead shapes such as those shown in Figures 7(b) and (Q) are unavoidable, and when the hot wire welding method described above is used in combination, the bead shape defects become noticeable, and it is difficult to improve them. desired.

A technical object of the present invention is to make the bead shape by profile welding combined with hot wire welding into an ideal bead shape.

01 Means for Solving the Problems The present invention will be explained using FIG. 1 which is an embodiment of the invention.
While forming an arc 9 between and the welded part 15,
The present invention is applied to a welding method and apparatus in which the additive wire 7 is fed into the arc and welded while being melted.

The above technical problem is solved as follows.

During the tracing movement in which the electrode 4 is separated from the welded part 15, when the amount of change in the magnitude of the successive tracing movements increases, the amount of melting of the additive wire 7 is reduced, and when it decreases, the amount of melting is increased. Further, during the tracing movement in which the electrode 4 approaches the part to be welded 15, when the amount of change in the magnitude of the successive tracing movements increases, the melting amount is increased, and when it decreases, the melting amount is decreased.

Further, the device of the present invention has a drive means for holding together the electrode 4 that generates an arc 9 with the part 15 to be welded and the additive wire 7 fed out to the part 15 to be welded, and driving the electrode 4 in a predetermined welding direction. 21, a parameter adjusting means 35 for adjusting a parameter related to the amount of melting of the additive wire 7, for example, the supplied power, a displacement detecting means 101 for detecting the displacement of the electrode 4 from the part to be welded 15, and the magnitude of the displacement. and a correction means 22 for controlling the driving means 21 according to the direction to cause the electrode 4 and the additive wire 7 to move in a tracing motion in a first direction in which the electrode 4 and the additive wire 7 move away from the part to be welded 15 and in a second direction in which they approach the part to be welded. calculation means 32 for calculating the amount of change in the magnitude of the movement;
and a control means 33 for controlling the parameter adjustment means 35. This control means 33 controls the parameter adjusting means 35 so that when the amount of change in the magnitude of the movement increases in the case of tracing movement in the first direction, the amount of melting is reduced, and when it decreases, the amount of melting is increased. do.

Further, in the case of tracing movement in the second direction, the parameter adjusting means 35 is controlled so that when the amount of change in the magnitude of the movement increases, the amount of melting is increased, and when it decreases, the amount of melting is decreased.

81 action When the electrode 4 moves in the first direction away from the part to be welded 15, when the amount of change in the magnitude of the sequential tracing movement increases, for example, the supplied power is reduced to reduce the amount of melting of the additive wire 7. is reduced, and when the amount of change decreases, the amount of melting is increased. Therefore, an ideal bead shape can be obtained without forming a convex bead as in the conventional case.

In addition, when the electrode 4 makes a tracing motion in the second direction approaching the part to be welded 15, when the amount of change in the magnitude of the successive tracing motion increases, the amount of melting of the additive wire 7 can be increased, for example, by increasing the supplied power. is increased, and when the amount of change decreases, the amount of melting is reduced. Therefore, the bead shape does not have an insufficient throat thickness as in the conventional case, but becomes an ideal bead shape.

It should be noted that in the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used in order to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Embodiment Figure 1 shows the overall configuration when the copy welding device according to the present invention is applied to a consumable electrode welding method, and the same parts as in Figure 3 are given the same reference numerals to indicate differences. I will mainly explain the points.

Welding torch 3 and wire guide 6 are integrally held by robot arm 21. The robot arm 21 is driven and controlled by a robot controller 22, and moves along a target welding line 12 (see FIG. 2(a)) set in a predetermined X-axis direction, and also moves along a Y-axis direction perpendicular to the X-axis. It vibrates with a predetermined amplitude. The maximum deflection position 42 (see FIG. 4) of the robot arm 21 is detected by the position detector 23. This is, for example, the robot controller 22
This is done by monitoring the output of a command to the robot arm 21 to reverse its driving direction. A method of directly detecting the actual position of the robot arm 21 may also be used. Welding wire 4, which is a consumable electrode, is fed at a predetermined speed by a feed motor (not shown), and additive wire 7 is fed by feed motor 2, which is a consumable electrode.
4, the paper is sandwiched between a rotating roller 25 and a fixed roller 26, and fed at a predetermined speed. The feeding speed of this addition wire 7 is controlled by a motor controller 27.

The welding current flowing through the welding wire 4 is detected by a current detector 28, filtered by a filter circuit 29, and sent to a pair of sample and hold circuits 30a.

input into the mouth. When the position detector 23 detects that the robot arm 21 has moved to the maximum deflection position 12, the two sample and hold circuits 30 sample and hold the welding current input at that time. The pair of welding currents held by the deviation device 31
The deviation is taken by the robot controller 22.
is input to the differentiation circuit 32. robot controller 2
2 drives and controls the robot arm 21 so that the deviation becomes O.

Differentiator circuit 32 differentiates the deviation signal with respect to time and inputs the result to function generators 32 and 33. The function generator a32 outputs a correction amount .DELTA. of the current applied to the addition wire 7, which is determined according to the differential signal, and the correction amount .DELTA. is input to the power regulator 35. The function generator 34 inputs to the motor controller 27 a correction amount ΔN of the rotation speed of the feed motor 24, which is determined according to the differential signal.

Here, the robot arm 21 controls the driving means by power adjustment @
35 is a parameter adjustment means, sample and hold circuit 3
1-1 and the deviation device 31 constitute the deviation detection means 101, the robot controller 22 constitutes the correction means, the differentiation circuit 32 constitutes the calculation means, and the function generators 33 and 34 constitute the control means.

The detailed operation of the hot wire welding type copy welding apparatus in which each part operates in this way will be explained.

Now, it is assumed that the initial target welding line 12 and the actual welding line 11A15 have a relationship as shown in FIG. 2(a). Figure 2 (a
), the vertical plate 2 installed perpendicularly to the lower plate 1 is distorted as shown in the figure, and the section R
1, the welding torch 3 moving along the target welding line 12 approaches, moves in parallel in section R2, and moves away 1 in section R3.
In section R4, the case where parallel movement occurs again is exaggerated.

Fig. 2(b) shows the deviation signal δ, and Fig. 2(c) shows the time change of the power correction amount ΔW. , the time interval is set such that the maximum runout position is reached at that point. In other words, the welding current is sampled in the sample-and-hold circuit 30A at even-numbered time points such as time points tzs, t4, and so on, and at time points t□, 72. At odd-numbered points in time, the welding current is sampled at the sample and hold circuit 30. Then, at each odd-numbered time point t, t1. ...
The deviation between the two sampled values is taken, and the amplitude center of the welding torch 3 is adjusted so that this deviation becomes O.

The target welding lines 12t, 12t, 12ti, . . . are sequentially reset.

Now, at time t, the welding current at the maximum runout position A is held in the sample hold circuit 30B, and at time t0, the welding current at the maximum runout position is held in the sample hold circuit 30, and the deviation at position 41 is It will be done. Section R
In 1, the welding torch 3 performs a tracing motion (trailing motion in the first direction) that approaches the actual welding line, so the welding current at the maximum deflection position becomes large, and the deviation signal from the deviation device 31 becomes negative. This result shows a value of -61.

The robot controller 22 drives and controls the robot arm 21 so as to shift the amplitude center of the welding torch 3 to the A side by an amount corresponding to 1δ,1. and.

The robot controller 22 resets the target welding line 12t1 passing through the changed amplitude center and parallel to the initial target welding line 12.

On the other hand, the differentiating circuit 32 has an input deviation of 0 at time t0.
Input deviation at 1 time point t = -δ, negative differential value -
Output D-engine. Due to this -D□, the function generator 33 is
A negative correction amount -ΔW of the power supply corresponding to the 1D power 1 is sent to the power regulator 35, and the power regulator 35 reduces the output power of the power supply power source 8 for the addition wire 7. therefore,
The amount of melted additive wire 7 is reduced. Further, the function generator 34 generates a negative feed motor rotation speed correction amount according to the D-
ΔN1 is input to the motor controller 27, which also slows down the feeding speed of the addition wire 7.

As mentioned above, at time t1, the center of deflection of the welding torch 3 is shifted to the A side, and the welding torch 3 is moved along the target welding line 12tY.
As time progresses, at the next sampling time t2, the welding current at the maximum runout position A is again held by the sample and hold circuit 30A, and at time t3, the welding current at the maximum runout position is held at the sample and hold circuit 30A. Since the target welding line 12ti after the change approaches the actual welding line 15 in the same way as at time 〇~time t□, both sampling values have a large maximum deflection position opening, and the deviation device 31 outputs 1δ. do. Therefore, the amplitude center of the welding torch 3 is further shifted to the A side by the robot controller 22. Also, at this time, 1δ31>1δ11, and the differentiating circuit 32 operates at time t.
-D as the time differential value between 1 and time t1.

Since it outputs (LD31>LD1+), the function generator 3
3 inputs -ΔW, (1ΔW, +>+ΔW 1) to the power regulator 35. This further reduces the power for the additive wire 7.

Next time tst time tff1 time 1. Then, since the deviation devices 31 each output a deviation signal equal to 1 δ3, the amplitude center of the welding torch 3 shifts to the A side accordingly.
The trajectory of the welding torch 3 is step-like, such as from 12t1 to 12t. Since the output of the deviation device 31 is equal at each time point t6, time point t7, and time point t, the output of the differentiating circuit 32 is 0, and the power regulator 35 adjusts the power [8] with the adjusted power changed at time point t. Since controlling, time t, ~t.

The power supplied to the additive wire 7 does not vary between the two.

Similarly, the feeding speed does not change either.

As explained above, in the section R1, the welding torch 3 performs the tracing motion, and the supply power and feeding speed of the additive wire 7 are adjusted according to the amount of variation in the magnitude of the tracing motion, which causes the welding torch 3 to move away from the welded part 15. Since it is controlled so that it decreases from the initial setting value, it does not have a convex peak shape like the conventional one.
This creates an ideal bead shape.

On the other hand, since the time point t and thereafter becomes the parallel section R2, the time point t
This is because the welding currents at the 49 maximum runout positions sampled at 1° and at time t are equal to each other, and the output of the deviation device 31 at time t becomes 0.

The amplitude center of the welding torch 3 is not changed. Further, the output of the deviation device 31 at time t is -53, the output of the deviation device 31 at time t is O, and the differentiator 32 outputs a positive differential signal. Therefore, the function generator 33 is +Δ
W engineering (1ΔWii1=ΔW, 1) is input to the power regulator 35. Therefore, the power regulator 35 increases the output of the power source 8 so that the power at the start of welding is supplied to the additive wire 7. Similarly, the function generator 34 outputs +ΔN11 (1ΔN, 1
=1ΔN31) is input to the motor controller 27, so the addition wire 7 is fed at the initial setting value.

In a section R3 where the welding torch 3 separates from the actual welding line 15, a copying motion (copying motion in the second direction) is performed, which is completely opposite to the section R1.

When the welding currents at the 49 maximum amplitude positions are sampled at time t20 #t21, the time t. The deviation signal at is +62i, and the differential signal is +D2□.

The robot controller 22 shifts the amplitude center of the welding torch 3 toward the mouth side, and the power supplied to the additive wire 7 increases, increasing the wire feeding speed. As a result, the seventh
The bead shape as shown in FIG. 7(c) is not obtained, but the ideal bead shape as shown in FIG. 7(a) is obtained.

Furthermore, at the time t zs t t as after the welding current sampled at the time tzst tz□ moves the amplitude center further toward the mouth side at the time t2□, the position A is reached.

The sampling welding currents at the ports are equal, the deviation signal at time 2S is O1 differential signal is +Do, and the power correction value is -ΔW29
becomes. As a result, at time tzs the amplitude center of the welding torch 3 remains unchanged and the power and feed rate of the dosing wire 7 are reduced to the initial set values.

With the above operation, when the welding torch 3 moves in the first direction away from the actual welding line 15, the additional wire 7
The power to the welding torch 3 and its delivery rate are reduced.
In the case of a profiling movement in the second direction, where the welding line 15 approaches the actual weld line 15, the power to the dosing wire and its feed rate are increased, so that an ideal bead shape is always obtained during hot wire profiling welding.

In addition, although the consumable electrode welding method was explained above,
The invention is equally applicable to non-consumable electrode welding methods. Further, although arc sensor type copy welding has been described, the present invention can also be applied to copy welding using various other methods. Furthermore, although both the parameters of the power supplied to the addition wire and the feeding speed were controlled in synchronization with the tracing control, only one of them may be controlled.

G0 Effects of the Invention According to the present invention, when the electrode is traced along the actual welding line, the amount of melted wire added is controlled according to the trace control, so that an ideal bead shape can always be obtained.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an example of a copy welding apparatus according to the present invention. FIG. 2(a) is a diagram illustrating the tracing motion of the welding torch in this embodiment, FIG. 2(b) is a time chart of the deviation signal, and FIG. 2(c) is a time chart of the power correction amount. Figures 3 to 7 explain conventional examples. Figure 3 is a diagram explaining conventional hot wire welding, Figures 4 to 6 are diagrams explaining copy welding, and Figure 7 is a diagram explaining bead welding. It is a figure showing a shape. 1: Lower plate 2: Standing plate 3: Welding torch 4: Welding wire 5: Earth dragon g
6: Wire guide 7 Additive wire 8:
Sub-power supply 12 Target welding line 15: Actual welding line 21, robot arm 22 Robot controller 23 Position detector 24: Feed motor 28 Current detector 30, 30: Sample hold circuit 31: Deviation device
32: Differentiation circuit 33. 34: Function generator 35: Power regulator 101: Parameter adjustment means

Claims (1)

[Claims] 1) An arc is formed between the electrode and the part to be welded while making a tracing motion along the part to be welded, and an additive wire is fed into the arc to melt and perform welding. In the welding method performed, during a tracing movement in which the electrode separates from the welded part,
When the amount of change in the magnitude of the sequential tracing movement increases, the amount of melting of the added wire is reduced, and when it decreases, the amount of melting is increased; and during the tracing movement in which the electrode approaches the welded part, A method of copy welding, characterized in that when the amount of change in the magnitude of the copy motion increases, the melt amount is increased, and when it decreases, the melt amount is reduced. 2) a driving means that holds together an electrode that generates an arc between the welding part and the additive wire fed out to the welding part and drives it in a predetermined welding direction; a parameter adjusting means for adjusting a parameter to be welded; a displacement detecting means for detecting a displacement of the electrode from the welded portion; and a displacement detecting means for detecting a displacement of the electrode from the welded part; and controlling the driving means according to the magnitude and direction of the displacement to correction means for causing a tracing movement in a first direction away from the welded part and a second direction in which it approaches the welded part; a calculation means for calculating the amount of change in the magnitude of the sequential tracing movement; When performing a tracing motion, the parameter adjusting means is controlled so as to reduce the melting amount when the amount of change in the magnitude of the motion increases, and increase the melting amount when it decreases, and When moving, the control means controls the parameter adjusting means so as to increase the melting amount when the amount of change in the magnitude of the movement increases, and to decrease the melting amount when the amount of change decreases. Profile welding equipment.