JPS6082271A - Short-circuit transfer arc welding machine - Google Patents

Abstract

PURPOSE:To provide a titled welding machine which maintains the specified repetitive period of an arc and short circuit and performs uniform welding with less spatters by controlling the electric power within the lapse time in the stage of the short circuit and controlling the electric power within the lapse time on the basis of the final electric power for the short circuit in the stage of the arc. CONSTITUTION:Electric power WS is made 0 at tS=0 in the stage of starting a short circuit then the power WS is quickly increased t2 to transfer and diffuse smoothly the molten metal to the part to be welded without spatters in short-circuit transfer arc welding. The short circuit is maintained in succession with the slightly increased power WS and is ended in the prescribed time TS. Electric power WP2 in the stage of an arc is inputted on the base of the power WS in the stage of ending the short circuit then the input Wa is gradually decreased to effect satisfactory penetration of the molten metal within the prescribed time TA in accordance with the decrease in the arc distance owing to the growth of the molten granule at the wire head. Such control 28 is accomplished by a computer operation 46 and the uniform short circuit transfer arc welding with less spatters is accomplished.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a short-circuit transitional arc welding machine, particularly to a wire electrode (hereinafter also simply referred to as a wire) and a base material, which frequently cause short circuits and arc occurrences. This applies to items that require all welding.

[Prior art]

Conventionally, there has been a device of this type as shown in FIG.

The device shown in the figure includes a DC motor 10.3-phase transformer 68
, thyristor rectifying element group 70, DC reactor 12, wire N pole 14, morph 1 for feeding the wire to the welding torch
6, a welding torch 18, a wire reel 22, etc. 20 indicates the entire base material.

Next, its operation will be explained.

The welding machine described above performs welding while repeating short circuit and arc discharge. That is, welding is performed by melting the welded portion between the tip of the wire and the base metal during an arc, and transferring the melted tip of the wire to the base metal during a short circuit.

Here, the operating principle of welding by short circuit and arc discharge will be explained.

While applying a voltage between the welding torch 18 and the base material 20 from the DC power source 10 via the DC reactor 12, the base material 20
f! ! 14-karat gold wire is fed into l at a constant speed. Then, the wire and the base metal are short-circuited, the welding current rises with a time constant determined by the DC reactor 12 and the short circuit resistance, and arc discharge occurs. When arc discharge occurs, the welding current falls with a time constant determined by the DC reactor 12 and the arc resistance, causing a short circuit again.

As described above, depending on the balance between the current supply amount and the wire feed valve, short circuits and arc discharges are periodically repeated as shown in FIG. 2.

By the way, since the conventional short-circuit transitional arc welding machine is prussically oxidized as described above, the short-circuit period changes due to minute fluctuations in the welding I-chi position or the base metal position. As a result, the heating element during the arcing period changes, the size of the molten ball melting during the arcing period, and the amount of droplets transferred during the short circuit period change greatly, and the so-called creeping of one arc becomes a phenomenon. 1
An unstable welding phenomenon called "or 1-stapping phenomenon" occurs.As a result, there are problems such as large spatters and defects in the weld bead.

[Summary of the invention]

This invention was made in view of the conventional problems mentioned above, and its purpose is to provide a short-circuit transitional arc welding machine that does not cause large spatter or defects in the weld bead. It's about doing.

In order to achieve the above object, the present invention includes a means for detecting instantaneous power during welding, a means for setting a total welding target power,
``In a short-circuit transition arc welding machine equipped with a means for comparing the H-time power and the target power, and a means for controlling the welding current based on the comparison result of the comparison means, when welding is in a short-circuit period, , the above target power is set to the short circuit elapsed time (
) When the welding is between arc n71, set the above target power to depend on the arc elapsed time, and use this to set the target power at the time of arc occurrence to It is assumed that kItfGk is made to depend on the short-circuit period immediately before.

[Embodiments of the invention]

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 shows an embodiment of a short #5F, 1 row arc welding machine according to the present invention.

The welding machine shown in the figure has a DC power supply 10 and a welding current of 0N-
Power transistor 64 for OFF control, DC reactor 12, flywheel diode 66, current detector 2
4, a voltage detector 26, and a control circuit a28 for controlling the welding current 2 ON/OFF.

First, welding wire 14 is supplied to welding torch 18 from wire reel 22, and welding current Ai and welding voltage Vi are detected by current detector 24 and voltage detector 26.

The detected welding current At is input to the instantaneous power setting device 30.

Furthermore, the detected welding voltage Vi is determined by the instantaneous power setting device 30.
and target voltage setter 34 and flilJ computer 46, l10 (input/output) interface 38'
i, respectively.

The control computer 46 determines whether there is a short circuit or an arc. Further, this computer 46 inputs the X and Y signals to I10.
It is applied to the short circuit time setter 42 and the arc time setter 44 via the interface II 40 ffi. This provides an indication of short circuits and arcs.

A short circuit time +d6 and an arc time ta are set in the short circuit time setter 42 and the arc time setter 44.

This setting state is input to the computer 46 via the I10 Intern Eight II4 (1).

The computer 46 calculates the short circuit waveform factor and the peak arc power value Wp2 based on the short circuit time 1 s. Also, based on the arc time ta, the arc waveform factor af
calculate. The results of these calculations are each output to the I10 interface fs IT[4B. .

The wire feeding speed signal A2·Vw which is received by the amplifier 58 and amplified by A2 times is the target short-circuit power W.
They are multiplied by each other in the s setter 56. This power n result is
The target short circuit power W s (W s =A2·Vw−s) is input to the target power setting device 60 .

Also, the arc waveform factor a and the peak arc 111. Force value W
p2 is added, and p is mutually reduced by the vessel 50. This subtraction result (W p 2- a ) is the target arc power S (
In the 7° setting unit, the signal is multiplied by q by the wire feed speed signal AI·Vw, which is amplified by A1 times in the amplifier 54.

Then, this multiplication result is the target arc power Wa (W a
= A 1°Vw (Wp 2-a) ) as E
lt! 'A power setter 60 is input, and
Comparator 6 as target power Wo (Wo=Wa+Ws)
2 is input.

Note that the target power WO is finely adjusted by the difference voltage (Vo-Vi) between the average welding voltage Vi and the target voltage (2) 0.

The comparator 62 receives the instantaneous power Wi from the instantaneous power setting device 30.
and the target power Wo, and if Wi>WO, an OFF signal is sent to the power transistor 64. Conversely, if Wi (Wo), an ON signal is sent to the power transistor 64. This causes the welding current Ai to turn ON -01.
Perform "F control".

FIG. 5 shows an overview of the control program executed by the computer 46 according to flowchart 1.

In this control program, in step 101, the welding voltage ■i is taken in from the I10 interface I, and in step 102, a short circuit and an arc are determined by transmitting the welding voltage Vi and the threshold voltage Vc. . Depending on the result of this determination, the short circuit power waveform setting routine 200
Also, execute one of the arc power waveform setting routines 201.

The short circuit power waveform setting routine 200 and the arc power waveform setting routine 201 are performed in the droplet state modes 1 to 1 shown in FIG.
Follow mode 11. Figure 4 is high-speed photo analysis P! 1 is a conversion diagram created based on the results, and shows modes of droplet transfer and generation during a short circuit period and an arc period.

Next, we will explain the control of the short n current waveform setting routine 200 (III).

In the first step 111, the arc waveform factor af+' OJ
9Q, and in step 112 I10 Intern Eight m
output a=Qfc. Also, steps 113 and 114
In step 115, X'fc-1-OJ and Y'trlJ are defined as X'fc-1-OJ and Y'trlJ, and X and Y signals are output to the I/O-r interfaces T and I.

Next, in step 116, the elapsed time after the wire is short-circuited, that is, the short-circuit time ts, is
Import from 1. Then, in subsequent steps, the peak arc power value wp2 and the signature waveform factor S are calculated according to the short circuit time ts.

Here, the peak arc power value Wp2 determines the arc power value during arc regeneration, and the peak arc power value Wp2 is determined by analysis from the high-speed photograph shown in FIG.
It has been found that the control should be performed in a manner that depends on the short circuit time T8. In other words, if the short circuit time TS is long, the melted wire will migrate to the base metal side, so in the next arc period, the wire will melt by the amount that migrated to the base metal side during the short circuit.
For example, the molten beads generated during the arc period can be controlled to be constant.

Therefore, in step 117, Wp according to the short circuit time tS is
2 (Wp 2 = f 2 (ts)) and ℃,
Wp to I10 interface III in step 118
Outputs 2. By doing this, the waveform of Wp2 in the time chart of the generation process of the power waveform shown in FIG. 6 is outputted from the I10 interface 1 to the 1 section.

Regarding the short-circuit waveform factor S, the period from mode 6 to mode 7 in FIG.
) It turns out that it is better to inject power into the wire. By the way, if a large amount of power is injected during the tS (t1 period),
This causes an instantaneous short circuit that does not cause droplet transfer t-, and during the next arc Jjl1, the molten ball becomes larger, so that the short-circuit period is disturbed.

Also, from mode 7 to mode 8, tl(ts(t2
It has been found that during the period, it is desirable to inject all the power so suddenly that the arc does not regenerate, forming a fin at the tip of the shorted wire.

From mode 8 to mode 11, Tsumashi [2kuts〈13 J
In an ill bar, when arc regeneration is performed by increasing power injection with a gentle slope, the number of spatters generated during arc regeneration remains constant. It was also found that the amount of spatter was smaller overall than the previous one, and the size of the spatter was smaller.

Furthermore, when the short circuit time ts becomes 13 or more, in order to prevent the unmelted wire from plunging into the base metal, arc regeneration is forced by suddenly injecting electric power, and this causes the Rustasoping phenomenon. control to prevent it from happening.

Therefore, for the short waveform factor S, the computer 4
At step 6, the following control program is executed.

That is, in step 119, the short circuit time 1S and time t1 are compared. If the comparison result is tS(t1), the short circuit waveform factor s'1irOJ is defined in step 120, S is output to the I10 interface (2) in step 126, and the process returns to step 101.

If the above comparison result is not 15<11, then in step 121 the short circuit time ts and time t2 are compared. The comparison result is 1. If <12, then step 122
The short end waveform factor 5iTs=t'3 (ts t 1) is defined in step 126, and si is output to the I10 interface (2), and the process returns to step 101.

Furthermore, if 1s<12, the short circuit time ts' and time t3 are compared in step 123, and the result is ts<t
If a, then in step 124 the short circuit waveform factor S is set to 5=f4
(ta t2)+f3(t2), step 12
At step 6, S is outputted to the I10 interface (12) and the process returns to step 101.

Furthermore, if ts<ta, then in step 126 the short circuit waveform factor 5is=f5(ts-ta)+f4(ta
)+f3(t2), outputs I10 interface IIIKst in step 126, and returns to step 101.

As described above, the 'A1tR waveform factor S in the time chart of the target power waveform generation process in FIG.
0 interface III to the outside.

Next, control of an example of the arc power waveform setting routine 201 will be explained.

In step 103, a short waveform factor 5ilOJ is defined, and in step 107, X and Y signals are output to the 10 interface 11. In step 108, the elapsed time since the arc was regenerated, that is, the arc time taIf10 is taken in from Intern Eighth J[. In step 109, the arc time ta
A (a=f 1 (ta)) corresponding to is calculated, and at step 110 a small af output is output to the I10 interface IU, and the process returns to step 1 (11).

As described above, the arc waveform factor a in the time chart of the target power waveform generation process shown in FIG. 6 is outputted from the I10 interface III to the outside.

Here, FIG. 7 shows an embodiment of the control circuit portion of FIG. 3.

In the same figure, the welding current AI detected by the current detector 24 is amplified by the amplifiers Gl and 02, and then the welding current AI in the instantaneous power setting device 30 is input to The signal Mlr is input to the XY input terminals of, for example, Analog Devices' AD-532J.

Further, the welding voltage Vi detected by the voltage detector 26
is amplified by amplifier G3, and then output to the Y terminal of #In device M1 in instantaneous power setting device 30, average voltage setting device 32
and is input to the A/D converter 72. '#Jr calculator M1 multiplies welding current Ai and welding voltage Vi to calculate instantaneous power Wi. This instantaneous power Wi
is amplified by amplifier q4, and then the resistance ratio of comparator 62 is 1.
is input.

The average voltage setter 32 includes an amplifier G5 and a capacitor C1.
, an averaged voltage VcyIc is created by the resistor R5. This voltage Vc is input to resistor R6 within adder 36.

In addition, the target voltage VO is set using a variable resistor (volume) ■几1
and is input to the resistance ratio 7 in the nailer 36 via the voltage follower circuit G6.

In the acclimatizer 36, the average voltage -Vi and the target voltage V.

Add. This added signal (Vo −V i
) is input to the resistance ratio 2 in the comparator 62.

In the short circuit time setting device 42, first,
4 to the base of the transistor Illrl. Then, when X=1, the transistor Tri is O
The circuit enters the FF state, and while this state continues, the amplifier G8 and the capacitor C2 perform an integration operation, and a voltage corresponding to the short completion time ts is output. This voltage is A/l)
The signal is converted into a digital signal by the converter 80 and input to the I10 interface (2).

Further, when Y=1, the transistor Tr2 is in the OFF state, and the time in the OFF state is integrated by the amplifier G9 and the capacitor C3.

As a result, a voltage corresponding to the arc time ta is output. This voltage is converted into a digital signal by the A/D converter 82 and input to the I10 interface (2).

The arc waveform factor a and the peak arc power value Wp2 output from the I10 interface llI48 are sent to the adder 5.
The signal is converted into an analog signal by D/A converters 78 and 76 in the 0. The arc waveform factor a is inverted by the amplifier GIO and then input to the amplifier Gll. Amplifier Gll
Then, the arc waveform factor a and the peak arc power value Wp2 are added. This addition output (Wp2-a) signal is output to the YnA terminal of the multiplier M2 in the target arc power Wa setter 52.

On the other hand, the short circuit waveform factor S output from the I10 interface m4B is converted into an analog signal by the D/A converter 74 and output to the Y terminal of the multiplier M3 in the target short circuit power Ws setting unit 56.

In the target arc power Wa setter 52, a multiplier M2 multiplies the wire feeding speed signal A1·Vw multiplied by A1 and (Wp
2-a) The signal is multiplied so that the target arc power W
a is calculated. This target arc power Wa is determined by the amplifier G
After being amplified by 12, the signal is input to a comparator 62 with a resistance ratio of 3.

In addition, in the target short-circuit type j)Ws setting device 56, the wire feed rate 1tf is multiplied by A2 in the amplifier 58.
i speed signal A2·Vw and short circuit waveform factor S signal are multiplied by n,
be done. Accordingly, the target short-circuit power Ws is calculated.

The calculated target short circuit power Ws is amplified by the amplifier G13 and then input to the resistor IL4 in the comparator 62.

In the comparator 62, II'! inputted to the resistance ratio 1! S time power Wi, resistance IL 2' K input 3iLfc (V
o-V i ) 4 (No. q, target arc power W a input to resistor 11.3.

and the target short circuit power Ws input to the resistance ratio 4 is added. Then, the added potential and the earth (ground) T
rL is compared with the comparator G14, and the comparison result is P
is output to. The signal output to this P causes the third
The power transistor 64 shown in the figure is ON-OFF controlled.

In addition, the resistance value and Ra are changed when the comparator G14 changes from ON to OFF.
This is to provide hysteresis when inverting to FF and when inverting from OFF to ON.

〔Effect of the invention〕

As described above, according to the short-circuit transition arc welding machine according to the present invention, when welding is in the short-circuit period, the target power is set to depend on the short-circuit elapsed time, and when welding is in the arc period, the target power is set to depend on the short-circuit elapsed time. By setting the target power to depend on the arc elapsed time and making the target power at the time of arc occurrence depend on the short circuit period immediately before the arc occurs, the repetition period of arc and short circuit can be reduced. It can be kept constant, thereby reducing the number of grasshoppers and making them fine (
As a result, a uniform weld bead can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional short-circuit transitional arc welding machine, FIG. 2 is a diagram showing a welding current waveform by the conventional welding machine, and FIG. 3 is a diagram showing an embodiment of the short-circuit transitional arc welding machine according to the present invention. , Fig. 4 is a conversion diagram showing modes of transfer and generation states of droplets during the short-circuit period and the arc period, Fig. 5.
FIG. 6 is a flowchart showing the execution program in the computer section of the welding machine according to the present invention.
The figure is a time chart showing the generation process of the target power waveform according to the present invention, and FIG. 7 is a diagram showing an embodiment of the control circuit portion of FIG. 3. Identical parts in each figure are given the same reference numerals, and 10 is a DC power supply;
12 is a DC reactor, 14 is a wire to a wire, 18 is a welding torch, 20 is a base metal, and 24 is a TrLI5! Detector, 2
6 is a voltage detector, 28 is a control circuit, 30 is an instantaneous power setting device, and 32 is an average i? 34 is the target voltage setter, 36 is the adder, 38.40.48 is the I10 interface ■, I [, III, 42.44 is the short circuit and arc time setter, 46 is the computer, '50 is an adder,
52 is a target arc power setting device, 56 is a target short circuit power setting device, 54.58 is an amplifier, 60 is a target power WO setting device,
62 is a comparator, 64 is a power transistor for controlling the welding current Aif, and 66 is a flywheel diode. Agent Patent attorney Masuo Oiwa (2 others) Figure 1 2171 Procedural amendment (spontaneous) November 1980 A3 Day 2, title of the invention Short-circuit transitional arc welding 3, relationship with the case of the person making the amendment Patent applicant address: 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name:
(601) Mitsubishi Electric Co., Ltd. Representative Jinhachi Katayama 4, Agent 5, Subject of amendment Akiyama Column for detailed explanation of the invention. 6. Details of amendments and above

Claims (1)

[Scope of Claims] (1) Means for detecting instantaneous power during welding, means for setting target power for welding, means for comparing the instantaneous power with the target power, and comparison results of the comparison means. In the short-circuit transition arc welding machine, the target power is set to be dependent on the short-circuit elapsed time when the welding is in the short-circuit period, and the welding is in the arc period. , the target power is set to depend on the arc elapsed time, and the target power at the time of shear arc occurrence is thereby made to depend on the short circuit period immediately before the arc occurrence. Final transition arc welding machine. (2. In claim (1), if the short circuit elapsed time is within the first predetermined time, the target power is kept as close to 0 as possible, and the short circuit elapsed time is within the first predetermined time.
The target power is increased at a steep gradient from the predetermined time to the second predetermined time, and after the second predetermined time, the target power is increased at a constant or gentle gradient. A short path transition arc welding machine featuring: (3) In claims (1) or (2), (11) a function of determining short circuit and arc based on welding voltage; (2) above Ml', when the result of determination is short circuit; (3) Function to correct the welding power at the time of arc occurrence; (4) Function to calculate the target power according to the short circuit time; (5) The result of the above judgment is (6) function to calculate the target power according to the arc time; (6) function to calculate the target power according to the arc time; A short path transition arc welding machine characterized by comprising a control means for performing the following in a predetermined procedure.