JPS5987981A - Automatic controlling method of oscillation width - Google Patents

Abstract

PURPOSE:To control automatically the width of a groove without using any special detector for the groove width by calculating the width of the groove in accordance with the detected values of the welding current and feed speed of a wire in an arc welding robot and the projecting length of the wire. CONSTITUTION:Objects 13 to be welded are welded, via a weld metal 21, by the shielded arc 20 from the top end of a feed wire 7 projecting from the top end of a tip 4 at the top end of a welding torch 1. The feed speed (v) of the wire is detected with a detector 23 for the amt. of revolution and average and effective welding currents IA, IE are detected with a detector 27 for current value. The detected values are inputted to a calculator 26. The relation of the functional relation determined beforehand is programmed in the calculator and the projecting length LE of the wire is calculated. The width of the groove is detected from the change pattern of the length LE by the oscillation of the torch and the torch is moved in accordance with the detected width of the groove. The oscillation width and welding speed are thus automatically changed according to the change in the width of the groove at the weld line.

Description

DETAILED DESCRIPTION OF THE INVENTION Regarding the method of automatically controlling the oscillation rate width in arc @ welding, it is designed to automatically change the oscillation rate width and welding speed according to changes in the groove width.

If the groove width of the weld line changes, if the onsill width and contact speed can be changed automatically in response to the change in groove width, a defect-free bath welded joint can be created (4J is smaller, but the groove width An arc welding robot that fully automatically controls the welding width and welding speed without using a special detector has not yet appeared.A welding robot that can easily and easily control the welding width and welding speed automatically It is hoped that the emergence of

The present invention meets such demands by detecting the welding current and wire feeding speed, which are the conditions during welding in arc bath welding using wire, and determining the groove width 'tIli based on these values. This invention provides an automatic width control method for fully automatic width control. The principle of the invention is:

When welding 1.--, the wire protrusion length should be changed in a pattern according to the groove width, and this wire protrusion length should be found from the ffJH current ■ and the wire feeding speed V. Based on TS'< t + In other words, when we calculate LE k from ■ and M while turning the welding torch, LE changes according to the turning rate, so
The groove width can be detected from this change pattern, and the onjirate width and welding speed can be fully adjusted in accordance with this groove width.

Note that although the arithmetic processing in the present invention can also be performed by analog calculation, in this application, a case where processing is performed by a digital computer will be described.

Embodiments of the present invention will be described below in detail based on the drawings 1.
Figure 1 shows 1% of the arc welding robot that realizes this example.
FIG. 2 is a block diagram extracting and showing a welding condition detection system and an arithmetic processing system. As shown in the figure, a welding torch 1 is connected to a welding power source 2 through a terminal 3 at A, and a tip 4 is attached to the center of the tip of the welding torch 1, and a shielding gas is applied to the outer periphery of the welding torch 1. A shield gas nozzle 5 to eject is attached. Then, the wire 7 wound around the reel 6 is passed from the base end of the welding torch 1 through the center of the welding torch 1 in the axial direction via a feed V roller 9.9ai driven by the wire feed motor 8. It protrudes from the tip of the balance wheel 4. This wire 7-, wire feeding motor 8
The feed rate is adjusted and controlled by a drive control power source 10. The base end of the bath welding torch 1 is attached to an oscillator 12 equipped with a drive motor 11, and is adapted to oscillate the bath tangent to the object 13 to be welded. j14 is a control power source for driving the drive motor 10. The turning rate device 12 is connected to a vertical movement device 16 equipped with a drive motor 15, and the vertical movement device 16 is connected to a left and right movement device J8 equipped with a drive motor 17. The position of the tip can be changed. In addition.

The left and right moving device 1B is supported by an arm 19 connected to a truck (not shown) that can move in a direction perpendicular to the plane of the paper, and the truck moves the welding torch 1 and its attached devices along the bath tangent line. . Thus, the object 13 to be welded is welded via the bath metal 21 by the arc 20 generated from the tip of the wire 7 toward the object 13 while being shielded by the shielding gas 22.

In gas-shielded consumable electrode arc welding that uses the above two devices, it has been experimentally found that there is a certain functional relationship among welding current (■), wire feed speed V, wire protrusion length LE, etc. It is being

Therefore, the above-mentioned apparatus is equipped with a mechanism for detecting the wire feeding speed V and the bath contact current as variables necessary for control. As a mechanism for detecting the wire feeding speed V, a rotation fine detector 22 such as a rotary encoder is attached to the feed roller 9a, and the signal from this rotation amount detector 23 is converted into a DC voltage (-1 as appropriate). A digital computing machine (hereinafter referred to as a computing machine) 26 that performs arithmetic processing as a digital computing machine via a conversion amplifier 24 and an analog-to-digital converter (hereinafter referred to as an A/D converter) 25 of a size that is small enough.
is input. In addition, a current value detector 27 such as a shunt is provided between the bath-contacting power source 2 and the workpiece 13 to detect the welding current ■, and the output signal thereof is sent to an amplifier 28 as appropriate to correspond to the average welding current IA. The signal is converted and amplified into a signal of a suitable magnitude and input to the computer 26 via the A/D converter 29, and an amplifier 30 converts the signal to a signal of a suitable magnitude corresponding to the effective welding current Ig. ! The signal is converted and amplified into a signal and inputted to the arithmetic unit 26 through the A/D converter 31. In this device, since the welding torch 1 is oscillated, the position of the @ contact torch 1 is required as a control element. Therefore, the oscillation device 12 is provided with an oscillation position detector 32 that detects the entire instantaneous oscillation position. The output signal is sent to the computer 2 through the amplifier 33 and A/D converter 34.
6 is input. In addition, the calculator 26 is provided with a setting device 35 via an A/■] converter 36 for presetting the minimum value LC of the distance between the tip and the object to be held. A circuit for controlling the position of the welding torch 1 is built into the computer 26 based on the above-mentioned input element group. /A converter) 37 to control the speed and sound of the truck to which the arm 19 is fixed.
(not shown), and at the same time a circuit for outputting the on-line rate width is also incorporated, and the output of the on-line rate width control signal is inputted to the control power source 14 via the D/A converter 38. be done.

During welding, the rotation amount detector 23 determines the wire feeding speed V, and the current value detector 27 determines the average bath contact current IA.
and the effective bath contact current II are detected.

These analog quantities are converted into digital quantities by the A/D converter 25.29.31 and applied to the arithmetic unit 26.

by the way.

Assuming that IAII average welding current (At 1 E: effective bath contact current V: wire feeding speed C&Z/s), there is an approximate functional relationship between the above quantities.

LE” f+ (IA, IE*v)
・・・・・・llll The relationship of the above formula (1) can be found in the "Research on Current-Controlled Wholesale Arc Welding" published by the R+ & Law Committee of the Welding Society of Japan, July 1980, middle frame page 5, u2.
Just like from the 1st type, $ is sweet.

The computing device 26 is programmed with the relation of equation (1) above. Therefore, the calculator 26 performs the following calculations.
@Average m-contact current for one worker and effective welding current II
and wire feeding speed V' (r-A/l) converter 29,
31.25 to the computer 26, the wire 7
The protrusion length Lg can be obtained from equation (11).

Now, the groove width has changed as shown in the second part.
3'
Fig. 4 is a cross-sectional view taken along the line 1-n.J The case where the groove width of the bath contact point in Fig. 4 is larger than the groove width of the welded piece T91 in Fig. 3; The oscillating width WV?-'s when onging within the groove shown in the figure: The curved turn of T and E is slightly sharp as shown in Fig. 5, and the oscillating width when onging within the groove shown in Fig. 4 LE's change-1 Hiba turn for W becomes broad as shown in FIG.

However, 111. This shows the case where the center line of the groove and the center line of the onjilate match. For any change pattern,
When the minimum distance Lc between the tip 4 and the weld metal 21 is set, the on-dilate width iJ:W+ (=Iw> −W
+I), Wz("1w-+-WBl)3, then the following control is performed by the operator 26.

(B1) Set the minimum value Lc using the setting device 35.

(b) As a result, when the welding torch moves inside the groove shown in Fig. 3 while turning, the wire protrudes and the pattern drawn by turning the length LE into the turning rate fvWj w is as described above; +' According to the program of the computer 26, the D/A conversion is performed by the computer 26 so that the direction in which the welding toe f1 turns is reversed when 5L E '' L c is reached. 4] Control 1 all the way!' Issue commands to 14.

p'4 Figure 4 shows a case where the groove width is larger than that in Figure 3.P) When the welding torch 1 moves inside the groove at an on-line rate L as in the case of LE and As mentioned above, the pattern drawn by W is as shown in Figure 6.

When LE=LC, a command is issued to the control power source 14 from the wave force 7 device 26 through all the D/A converters 38 so that the direction of the onward rate of the welding torch 1 is reversed.

) In this way, the onjirate width is controlled by the minimum value Lc.

On the other hand, if the welding speed is the same but the groove width is different, the bead height will be different. That is, when comparing HI in Figure 3 and 02 in Figure 4, HI >'H2, and the bead tl? As the layers increase, the difference in bead height due to the faster groove width becomes more noticeable. Therefore, in order to prevent this, the bath contact speed should be controlled according to the groove width. In this example, since the oscillation rate corresponding to the groove width can be detected, the oscillation rate should be approximately inversely proportional to the groove width. It is sufficient to control the welding speed to An output 't which is almost inversely proportional to Δ2 is outputted to the driving chisel source of one truck (not shown) through the D/A converter 37 to control the electric speed. 5. In this way, the bevel By controlling the onsylate width and welding speed according to the width, a defect-free bath weld joint with a uniform bead height can be obtained.

According to the present invention, as specifically explained in conjunction with the embodiments above, there is no need to use a special detector. 6 The full groove width can be detected from only the welding conditions 4. Even if the groove width changes, the onoscillation width and length speed will automatically change (this will ensure that a defect-free bath welded joint is provided. 5 , therefore unmanned 1 with high vitreous
Able to obey.

[Brief explanation of the drawing]

Part 1 (9) is a block diagram showing, in particular, the bath contact condition detection system and deduction processing system of the arc bath contact robot that realizes the embodiment of the present invention. Fig. 3 is a sectional view taken along the line L-1 in Fig. 2;
Figure 4 is a sectional view taken along the line II-1 in Figure 2, and Figure 5 is a cross-sectional view taken along the line II-1 in Figure 2.
Tip and @ for oncillation width within the groove shown in the figure
A graph of the variation f of the distance between the contact metal and the contact metal, No. 6 and 1, is a graph similar to that in FIG. 5 within the groove of FIG. 4. In the drawing. ■ is a welding torch 5, 4 is a tip, 7 is a wire, and 13 is a welded object. 20 is an arc, 21 is a weld metal 23 is a rotation amount detector, and 26 (Go operation 1,000) is a 36°27 current value detector. 'rf Fl' Li2 &T Mitsubishi Heavy Industries, Ltd. (l!p) Patent Attorney Mitsubishi Shibu (and 1 other person) Figure 3 Figure 5 Figure 6 W3. W4

Claims (1)

[Claims] It is possible to move the welding torch to any point in three-dimensional space and take any necessary torch posture, and it is also possible to generate an arc while energizing the welding torch using a wire, which is a consumable electrode. When welding, welding current (IA: average current, E: effective current)
and the wire feeding speed (vl), respectively.
Based on a predetermined relational expression, the above bath contact current CIA,
Ii) and the wire feeding speed (by performing one operation on each part of vl, the wire protrusion length LE)'e is determined, and the groove width is detected from the change pattern of the wire protrusion length Lg due to the onculation of the bath welding torch. , an automatic onsill width, characterized in that the onsill width and welding speed are automatically changed according to changes in the groove width of the bath tangent by moving the bath welding torch based on the detected groove width; Control method.