JPS60240379A - Automatic welding device - Google Patents

Abstract

PURPOSE:To obtain an automatic welding device that forms a good bead free from convex beeds in the groove by controlling weaving action and welding current synchronously. CONSTITUTION:A truck condition setting device 2, a weaving condition setting device 5 and a welding current condition setting device 8 are connected to a central processing unit (CPU)15 provided with a memory 16 and a timer 25. A truck 3 is provided in the CPU15 through the first D/A converter and a servo- amplifier 18, and the truck 3 is connected to the CPU15 through an encoder 19 and a counter circuit 20. A weaving action shaft 6 is connected to the CPU15 through the second D/A converter 21 and a servo-amplifier 22, and the action shaft 6 is connected to the CPU15 through a potentiometer 23 and an A/D converter 24. Further, a welding torch 10 is connected to the CPU15 through the third D/A converter 26 and a welding power surce 9, and weaving action and welding current are controlled synchronously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic welding device using low frequency pulse TIG welding means for weaving a groove in a welded object such as a tube or a flat plate.

[Technical background of the invention and its problems]

As shown in FIG. 1, a bogie control device 1 in this type of automatic welding apparatus that has already been proposed inputs data on bogie speed and travel distance set in advance to a bogie condition setting device 2, and controls the bogie ( The weaving control device 4 controls the conditions of the weaving operation 11 shown in FIG. Width B, weaving period T, weaving stop time T
The welding current control device 7 inputs each data of s and controls the weaving operation axis 6, and the welding current control device 7 sets the conditions of the welding current 12 shown in FIG.
In other words, peak current 1p, base 1i2i11b, peak time Tp゛, base time Tb = upslope time T
- Input each data of u1 downslope time Td, crater current Ic, and crater time TC, output the welding current command value to the welding power source 9, and set the above welding current 1 of the welding torch 10.
2 controls are performed. That is, the welding power source 9 operates according to the welding current value from the welding current control device 7.
A welding current is passed through the welding torch 10 to generate an arc. In this way, the automatic welding device described above has a weaving operation (see Fig. 2) 11 and a welding current (
(see FIG. 3) are separately controlled by the weaving control device 4 and the welding current control device 7, respectively.

However, as shown in FIG. 4, the above-mentioned automatic welding device cannot perform welding in a downward position, as is clear from the relationship between the groove 13a of the workpiece 13 and the welding electrode 14 of the welding torch 10. Even if the welding is performed in an upward position, the molten metal may be welded by its own weight, or the surface tension of the molten metal may not be able to overcome gravity, causing the groove 13a to
Form a convex build within. Further, the welding electrode 14 sufficiently melts the wall surface of the groove portion 13a, and the molten metal supplied as the welding material is applied to the groove wall surface, so-called 'wetting'.
Not only is it impossible to obtain a stable condition, but also a convex bead becomes noticeable when welding a narrow groove.

Therefore, in order to eliminate the generation of convex heat, a low frequency pulse T10 means is adopted to prevent the molten metal from overheating and expand and contract the molten pool, thereby preventing the culling of the molten metal. In addition, weaving is performed in a direction perpendicular to the weld line in order to sufficiently melt the wall surface of the groove, and furthermore, by taking a pause time at both ends of the weaving, the melting of the wall surface of the groove is promoted. is being attempted.

However, since welding using the above-mentioned low frequency pulse T10 means simply uses low frequency pulse TIG and weaving in combination, it is not clear at what position in the weaving the peak current of the pulse current is output; If the low frequency pulse TI is output at a location other than the wall surface of the
The effect of G and the effect of weaving cancel each other out, resulting in a defect, which is a major hindrance, especially when welding thick horizontal fixed pipes, and is applied to automatic welding of pipes in power plants where high quality is required. This is considered to be a major problem if this happens.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and is an automatic automatic welding method which aims to form a good bead without convex beads on a thick tube body by low frequency pulse TIG welding means. The present invention provides welding equipment.

[Summary of the invention]

The present invention provides a central processing unit equipped with a storage device and a timer with a trolley condition setting device, a weaving condition setting device, and a welding current condition setting device connected to each other, and a first
A trolley is provided via a D/A converter and a servo amplifier,
This trolley is connected to the central processing unit through an encoder and a counter circuit, and the 20th/A
A weaving operation axis is connected through a converter and a servo amplifier, and this weaving operation axis is connected to the central processing unit via a potentiometer and an A/D converter, and a third D/A converter is connected to the central processing unit. A welding torch is connected via a welding device and a welding power source, and the weaving operation and welding current are synchronously controlled.

[Embodiment of the Invention] Hereinafter, an illustrated embodiment in which the present invention is applied to low-frequency pulse TIG welding will be described.

Note that the present invention will be described with the same reference numerals assigned to the same mechanical members as those in the above-described specific example.

FIG. 5 is a block diagram of an automatic welding apparatus according to the present invention, and in this FIG.
A bogie condition setter 2, a weaving condition setter 5, and a welding current condition setter 8'' are connected to the input side of the , respectively, and the data preset in each setter 2.5.8 is the same as that described above. The central processing unit 15 is operated manually.

Further, this central processing unit 15 is provided with a memory device FLR16 and a timer 25, and this memory device 16 is adapted to store data input to the central processing unit @15.

On the other hand, on the output side of the central processing unit 15, a first D/A
A bogie (bogie driving device) 3 is connected to the converter 17 and a servo amplifier 18, and the bogie 3 is controlled by the central processing unit 15. That is,
The central processing unit 15 inputting the data from the bogie condition setting device 2 outputs the speed command value to the first D/Δ converter 17, where the speed command is D/A (digital/analog) converted. The value is input to the servo amplifier 18,
This causes the truck 3 to be operated. Further, an encoder 1 mechanically connected to the trolley 3
9 generates a pulse signal as the truck 3 moves, and this pulse signal is input to a counter circuit 20 connected to the encoder 19 to count the position of the truck 3. Further, a counter circuit 20 connected to the central processing unit 15 transmits a signal counting the position of the cart 3 to the central processing unit 15 to control the position of the cart 3. On the other hand, a second D/A converter 21 and a servo amplifier 2 are connected to the output side of the central processing unit 15.
A weaving operation axis 6 is connected via 2.
(The control of this weaving motion axis 6 is performed by the central processing unit 15. In other words, the central processing unit 15 inputs the data from the weaving condition setting device 5.
is the weaving speed νw = 2B/ (T-27s)
is calculated, and this speed command value is sent to the second D/A converter 21.
Output to. Here, the D/A converted speed command value is input to the servo amplifier 22, thereby operating the weaving motion axis 6.

Further, the output voltage of the potentiometer 23 mechanically connected to the weaving operation shaft 6 changes as the weaving operation shaft 6 moves, and the output voltage changes to an A/D converter connected to the potentiometer 23. 24, the position of the riding motion axis 6 is controlled by converting it into a digital quantity and inputting it to the central processing unit 15, and the weaving stop time is controlled by counting the time by 81 with the timer 25. It is supposed to be done.

On the other hand, on the output side of the central processing unit 15, a third D/
A welding torch 10 is connected via an A converter 26 and a welding power source 9, and the welding current of this welding torch 10 is controlled by the central processing unit 15.

That is, the central processing unit 15 inputting the data set in the welding current condition setting device 8 outputs the current command value to the third D/A converter 26, where the current command value is D/A converted. The value is output to the welding power source 9 to control the welding current of the welding torch 10.

Next, the operation of the present invention will be explained with reference to a time chart of synchronous control of the weaving operation 11 and welding current 12 shown in FIG. 6, and a 70-chill rate shown in FIG.

The weaving movement speed νw is determined based on the data of the weaving width B, weaving period T, and weaving stop time TS set in advance in the weaving condition setting device 5.
=28 (T-2TS), and the central processing unit 1
The information is stored in the storage device 16 of No. 5.

Next, based on the data of upslope time TIJ, base current 1b, and crater current Jc set in the welding current setting device 8, an upslope that linearly increases from crater current 1c to base current rb by upslope time lu is performed. Perform processing.

When the upslope process is completed, the weaving operation speed command value of +νW is output to the second D/A converter 21, the weaving operation 11 in the - (positive) direction is performed, and the base current command value is changed to the 30th /A converter 26. When the weaving operation axis 6 moves to the +B/2 position, the speed command value for stopping weaving is set to the 20th position.
/A converter 21 , thereby stopping the weaving operation 11 , and outputting the peak current command value to the third D/A converter 26 . The weaving stop time TS is counted by a timer 25, and when the weaving stop time TS elapses, a weaving operation speed command value of -νW is outputted to the second D/A converter 21, and -(negative)
A weaving operation 11 in the direction is performed, and a base current command value is output to the third D/A converter 26. When the weaving operation axis 6 moves to the -B/2 position, the speed command value for stopping weaving is output to the second D/A converter 21, thereby stopping the weaving operation +t and changing the peak current command value to the second D/A converter 21. Output to 3D/A converter 26. or,
The weaving stop time Ts is counted by a timer 25, and when the weaving stop time Ts has elapsed, it is checked whether welding has ended or not. If not, the above process is repeated from the + (positive) direction of weaving. On the other hand, when welding is finished, a downslope process is performed in which the welding current 12 is linearly decreased from the base current 1b to the crater current 1c in a downslope time Td.

When this downslope process is completed, the crater time T
Crater processing is performed by outputting crater current 1c for a period of time C.

In this way, welding current 12 is applied to weaving operation 11.
can be synchronized.

Incidentally, in the present invention, it goes without saying that the weaving operation 11 may be synchronized with the welding current 12, and
FIG. 8 shows a flowchart in which the weaving operation 11 is synchronized with the welding current 12.

That is, in another embodiment of the present invention shown in FIG.
Based on the data of b, riding speed ν=B/T
b is calculated and stored in the storage device 16.

Next, upslope processing of the welding current 12 is performed. When this upslope process is completed, a base force current command value and a weaving speed command value of +νW are output. Then, the base current time Tb is multiplied by the timer 25, and when the base current time Tb elapses, a peak current command value and a speed command value for stopping weaving are output. The peak current time is measured by the timer 25,
As soon as the peak current time Tp elapses, a base current command value and a weaving speed command value of -νW are output. The base current time 7b is counted by a timer 25, and when the base current time tb elapses, a peak current command value and a speed command value for stopping weaving are output,
The timer 25 counts the peak current time tp and waits until the peak current time To elapses.

In this way, the process of outputting the base current and peak current is repeated until welding is completed. However,
When welding is completed, the weaving operation 11 can be synchronized with the welding current 12 by -C1 by performing downslope processing and crater processing of the welding current.

〔Effect of the invention〕

As described above, according to the present invention, the central processing unit 15 includes the storage device 16 and the timer 25, the bogie condition setting device 2, the weaving condition setting device 5, and the welding current condition setting device 8.
A first D/A is connected to the central processing unit 15.
A truck 3 is provided via a converter 17 and a servo amplifier 18, and this truck 3 is connected to the central processing unit 15 through an encoder 19 and a counter circuit 20. A weaving motion shaft 6 is connected to the central processing unit 15 via a potentiometer 23 and an A10 converter 24, and a third D/A The welding torch 10 is connected via the converter 26 and the welding power source 9, and the weaving operation and welding current are synchronously controlled, eliminating the occurrence of a convex bead in the groove and improving the welding process. Not only can the metal be kept wet against the groove wall surface, but since there is penetration by the previous layer, there is no need for extra heat input, which saves energy and improves the groove route. This has excellent effects such as being able to maintain low heat input during welding near the part.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an automatic welding device that has already been proposed, FIG. 2 is a time chart showing weaving operation, and FIG. 3 is a time chart showing changes in welding current.
Fig. 4 is a diagram showing the relationship between the groove of a non-welded body and a welding electrode, Fig. 5 is a block diagram of an automatic welding device according to the present invention, and Fig. 6 is synchronization of weaving operation and welding current. A time chart showing the control, FIG.
-Chart, FIG. 8 is a flowchart showing another embodiment of the invention. 1... Bogie control device, 2... Bogie condition setting device, 3...
... Cart, 5... Weaving condition setting device, 6...
Weaving operation axis, 8... Welding condition setting device, 9...
- Welding power source, 10... Melting torch, 11... Weaving operation, 12... Welding current, 15... Central processing unit, 16... Storage device, 17... First D/A conversion 18... Servo amplifier, 19... Encoder, 20... Counter circuit, 21... 20th/A converter, 22... Servo amplifier, 23... Potentiometer, 24... A/D converter, 25... timer,
26...Third D/A converter. Applicant's agent Kiyoshi Inomata Figure 1, Figure 2, Figure 1, Figure 3, Rate 4, Figure 5, Figure 6, Figure 6, Figure 7, Figure 7.

Claims (1)

[Claims] The trolley condition setter, weaving condition setter, and welding current condition setter are connected to a central processing unit equipped with a storage device and a timer, and the first D/A is connected to the central processing unit.
A cart is provided via a converter and a length-bore amplifier, this cart is connected to the central processing unit through an encoder and a counter circuit, and a weaving operation axis is connected to this central processing unit via a second D/A converter and a nerve amplifier. This weaving operation axis is connected to a potentiometer and a
A welding torch is connected to the central processing unit via a /D converter, and a welding torch is connected to the central processing unit via a third D/A converter and a welding power source to synchronously control the weaving operation and the welding N flow. An automatic welding device characterized by: