JPS6289575A - Arc welding method - Google Patents

Abstract

PURPOSE:To automate welding by storing the oscillation both ends position of the previous layer to the final finishing layer, then by performing the groove width profiling of the upper layer of the stored layers based on the storing thereof. CONSTITUTION:A microprocessor 30 is provided and the motor 31 and driver 32 which oscillate a welding torch in the Y axis direction are arranged as well. The motor 37, driver 32 pulse generator 39 which drive the welding torch in X axis direction are further arranged. The pulse generator 35 directly connected to the motor 31 stores the stop position and reverse position in the Y axis direction of the torch to a memory 34. The microprocessor 30 controls the torch by reading out this memory content and performs the groove width profiling of the top layer. Due to the oscillation width being able to be controlled automatically the automation in welding is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to automatic welding of the upper layer where the groove wall has disappeared in multi-layer arc welding.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, in multi-layer welding, Japanese Patent Application Laid-Open No. 58-35064 discloses a method of controlling welding in the upper layer where the groove is covered with a weld bead and the groove wall has disappeared.

In this method, during oscillation welding of the layer before the final finishing layer or the previous layer, the position in the welding progress direction and the oscillation center or both end positions at that position are memorized moment by moment, and the oscillating welding of the final finishing layer is performed. This is a method in which welding and line tracing during welding are performed based on reading of the above-mentioned memory contents. However, although this method can automatically trace the weld line, if the groove width of the workpiece varies, the oscillation width is constant, so the line X at the top of the groove as shown in Figure 3
There was a problem in that a defect occurred in that the end edge Y of the bead was formed at a place where the bead was separated from the surface. Conventionally, to prevent this defect, an operator would monitor and adjust the oscillation width.

Furthermore, no method has yet been found to eliminate the unevenness of the extra bead of the finishing layer, prevent insufficient extra bead, and improve the appearance of the bead.

OBJECTS OF THE INVENTION The present invention provides a method for stably performing oscillation welding of a final finishing layer without monitoring the oscillation width by an operator even when the groove width changes, and
The purpose is to control the excess height to a constant level.

Structure of the Invention The arc welding method of the present invention is an automatic welding method in which the welding line of the workpiece and the width of the groove are traced while the welding torch is oscillated within the groove. The present invention is characterized in that the positions of both ends of the oscillate are memorized during welding of the layer, and the groove width is traced during welding in the upper layer of the memorized layer without reading out the stored contents.

First, during oscillation welding of the layer before the final finishing layer or the layer before it, the oscillation stop position is determined in advance as P +r, P ls, ..., P nr as shown in Fig. 2.
.

Pns, its components are expressed on the X axis (axis in the direction of welding progress) L
r, X+s, =-, Xnr, Xns are divided into Y-axis (axis in the groove width direction) Y, r, Y, s, -, Ynr, Yns and stored in the storage device.

Here, the welding method according to the present invention will be explained with reference to the flowchart of FIG. Here, in S T A RT, it is assumed that the welding torch is stopped at an arbitrary oscillation stop position @P'+r on the r side (the side where the Y coordinate is smaller). First, in step S1, the X coordinate X° at this point in time is determined. In the next step S2, the smallest Xjs (Xjs in Fig. 2) that is larger than XZr is searched among the stored oscillation stop positions on the S side (the side where the Y coordinate is large), and in step S3, the position is determined using the formula 0. The inversion position Y'+ is obtained by adding a preset constant value α to the Y coordinate Yjs of
Let it be s.

v゛,s = Yjs+α ・・・・・・■When the welding torch reaches the position Y'Is, step S
After the oscillation stop time at the end on the r side of the groove has elapsed, the welding torch is moved in the direction in which the Y coordinate increases until the Y coordinate becomes Y'+s and then stopped at step S6.

Next, find the X coordinates X', s at this stop position P', s, and select the minimum Xkr (X, r ) is searched for in step S4, and then, in step S7, the Y coordinate Ykr of that position minus the above α is set as the inverted position Y'', r.

Y'=r=Ykr a --■ Step S9 after the oscillation stop time at the open end has elapsed
The welding torch is moved in the direction where the Y coordinate becomes smaller until the Y coordinate becomes Y'yr, and then stopped. Below S T A RT
By repeating the following operations, it was possible to follow the groove width using the final finishing layer.

Here, α was set to the same value on the r side and the S side, but in welding in a horizontal position, different values may be used to cope with hanging of the bead.

Next, the oscillation stop position P'nr in the welding method is
, by calculating the oscillation width from P'ns and controlling the welding speed inversely proportional to the change in value, or by controlling the wire feeding speed proportionally, the height of the excess buildup by the final finishing layer can be kept constant. We were able to achieve welding with a beautiful bead appearance.

There is no problem when performing normal welding using the above method, but M
Consumable electrode welding methods such as IG, MAG, Co, etc., TIG
When the groove width is wide, such as in the case of a large welding amount welding method, the oscillation pitch becomes rough, and the above method causes a defect in which the bead becomes uneven as shown in FIG. That is, the bead deviates as shown by W' with respect to an ideal bead W that is symmetrical from the center of the groove.

The method for solving this problem is as shown in FIG. 6, in step 5t-93 of the flowchart in which the position of the Y-axis component obtained by adding α to the stored stop position P2S is set as the opposite stop position.
Instead of the operation, it is expressed as P n5 (n is a natural number). In this method, the oscillation stop line indicated by Qi in FIG. 6 is obtained by linear interpolation of Pns, and the value obtained by adding α to the line is determined as the inversion position of the Y-axis component. The same method is used for determining the oscillation stop position in the opposite direction in step S8.

This allows it to be applied even when the oscillation pitch is wide.

FIG. 4(a) is an overall block diagram of a mechanism according to an embodiment of the present invention. In the figure, A indicates a material to be welded, which is welded along a groove K. 2 is a non-consumable electrode that generates an arc between it and the material to be welded A, 2 is a welding torch, and 3 is a welding torch that drives the welding torch 2 vertically (in the Z-axis direction in the figure) to perform constant arc length control. 4 is a Z-axis motor, 5 is an optical pulse generator directly connected to the sleeve of the motor 4, and the output of the pulse generator 5 is fed back to the motor driver 6. , controls the position of the welding torch 2 in the Z-axis direction. 7 is a mechanical transmission device that drives the welding torch 2 in the Y-axis direction in order to oscillate the welding torch 2, 8 is a motor for on-rate, and 9 is an optical encoder that generates a number of pulses according to the rotation m of the motor 8. occurs. 10 is a driver. 11 is a moving mechanism that moves the welding torch 2 in the direction X along the welding line, and this moving mechanism l! is equipped with a motor 13, and the motor 13
The rotation of the moving mechanism 11 is transmitted to a mechanical transmission means 12 including gears, etc., so that the moving mechanism 11 moves in the X direction in the figure along the rail lla.

14 is a pulse generator that outputs a signal according to the rotation of the motor 13, and 15 is a driver that drives the motor 13.

Using the devices 3 to 15 above, move the welding torch 2 to X.

Drive in three orthogonal directions of Y and Z. Further, 16 is a wire feeding tip, 17 is a filler wire, and this filler wire 17 is fed into the arc between the non-consumable electrode I and the groove by a mechanical feeding device 18 to form a bead. . 19 is a wire feed motor, and 20 is a tacho generator which feeds back its output to the wire motor feed driver 21 to control the wire feed speed.

In FIG. 4(b), 31 is the welding torch 2 in the Y-axis direction.
32 is the motor that drives the microprocessor 30 and performs oscillation.
Upon receiving a stop command, the motor 31 is driven to move the welding torch. In the welding method described above, the sequence is executed by the microprocessor 30, and the detected oscillation stop position is stored in the memory 34. 35 is an optical pulse generator directly connected to the motor 31;
6 is a counter that receives the output of the pulse generator 35 and outputs the position of the welding torch 2 in the Y-axis direction to the microprocessor 30.The output of this counter 36 stores the Y-coordinate of the oscillation stop position and also stores the reversal position. Detect. 37ζ-tX Tunichi Bu〒lff1koitsu V
Hatake? The driver receives start, stop, and speed commands from the microprocessor 30 and drives the motor 37.

39 is an optical pulse generator directly connected to the motor 37, and 40 is a counter that receives the output of the pulse generator 39 and outputs the position in the X-axis direction to the microprocessor 30.
Remember the coordinates. Reference numeral 41 denotes an α setting device consisting of a DIP switch, a volume control, and the like.

Effects of the Invention In the present invention, in the final finishing layer where the groove wall has disappeared, not only the weld line but also the oscillation width is automatically controlled, which eliminates the need for operators to monitor the oscillation width, which was required in the past. It has become possible to perform automatic welding that further reduces the burden on the operator and saves labor.

The present invention can be applied to welding methods for tracing the weld line and groove width of consumable electrode welding such as MIG, MAG, and Cot, or non-consumable electrode welding such as TIG.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing one embodiment of the arc welding method of the present invention, Fig. 2 is a graph showing the position of the welding torch in the method of Fig. 1, and Fig. 3 is a plane showing the defects that occur in the conventional welding method. 4(a) and 4(b) are block diagrams showing an example of welding equipment used in the method of the embodiment shown in FIG. 1, and FIG. 5 is a graph showing defects that occur when the groove gap is wide. FIG. 6 is a graph showing another embodiment of the present invention for eliminating the defect shown in FIG.

Claims (4)

[Claims] (1) In automatic welding, which traces the weld line and groove width of the material to be welded while oscillating the welding torch within the groove, both ends of the oscillate are An arc welding method characterized in that a position is memorized, and groove width tracing during welding in a layer above the memorized layer is performed by reading out the memorized content. (2) In welding the upper layer, a preset constant value is added or subtracted from the memorized positions of both ends of the oscillate, and the new positions of both ends of the oscillate are determined, and groove width tracing is performed. arc welding method. (3) In welding the upper layer, the oscillation stop line at both ends is calculated from the memorized oscillation stop position, and a preset constant value is added to or subtracted from the oscillation stop line to create a new oscillation stop line, and the groove width is followed. Request 1st
The arc welding method described in Section. (4) In welding the upper layer, the bead height is controlled by calculating the oscillation width from the positions of both ends of the oscillation and changing one or both of the wire feeding speed and the welding speed according to the change. Scope: The arc welding method described in any of the preceding items.