JPS58176072A - Arc welding machine - Google Patents

Abstract

PURPOSE:To obtain an arc welding machine which is capable of easily adjusting the repetition of a period of both polarity outputs, by connecting each DC power source for a reverse polarity output and a straight polarity output, to a series circuit of a welding arc and a reactor. CONSTITUTION:In an arc welding machine which outputs AC, a DC power source 1 for a reverse polarity output, and a DC power source 2 for a straight polarity output are connected to a series circuit consisting of a reactor 5, a welding electrode 6, a welding arc 7, a base metal 8 and a welding current detecting shunt 9, through transistors 3, 4. A controlling circuit 10 is provided, and when the reverse polarity output is supplied, the transistor 4 is off, the transistor 3 repeats on and off, and the arc 7 is controlled. Also, when the straight polarity output is supplied, the transistor 3 is off, and the transistor 4 repeates on and off. According to this mechanism, an optimum welding result is obtained against every plate thickness of an object to be welded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arc welding machine that outputs alternating current.

In a conventional AC arc welding machine, the frequency of its output must depend on the commercial frequency, and the time TRP for supplying reverse polarity output and the time TSP for supplying positive polarity output to the welding arc can be set arbitrarily. It's not a matter of adjusting its length. In addition, adjusting the output is troublesome because it must be done by changing the winding ratio of the transformer, etc. Also, since the output waveform is a sine wave, the voltage rises slowly and arc regeneration occurs. This becomes a hindrance to ignition.

The present invention solves these conventional drawbacks by making it possible to arbitrarily adjust the length of the time TRP for supplying reverse polarity output to the welding arc and the length of the time T'sp for supplying positive polarity output. Moreover, an arc welding machine whose output can be easily adjusted is obtained. Hereinafter, an arc welding machine according to the present invention will be explained using the drawings of FIGS. 1 to 4.

FIG. 1 shows an arc welding machine according to an embodiment of the present invention, in which 1 is a DC power source for reverse polarity output;
is a DC power supply for positive polarity output, and the DC power supply 1 for reverse polarity output and the DC power supply 2 for positive polarity output are connected to a reactor 5 and a welding electrode 6 via transistors 3 and 4. It is connected to a series circuit consisting of a welding arc T, a base metal 8, and a shunt 9 for detecting welding current. Further, the ON-OFF timing of the transistor 3.4 is controlled by the control circuit 1o so that the welding arc 7 becomes stable during steady welding f1. That is, during the time TRP for supplying the reverse polarity output, the transistor 4 is OFF and the transistor 3 is 0N-OFF, and during the time TsP for supplying the positive polarity output, the transistor 3 is OFF and the transistor 4 is 0N. -Turn OFF repeatedly.

FIG. 2 shows all the current waveforms when the output of the shunt 9 is fed to the interest circuit 1o on the constant current side aI'r:.

FIG. 3 shows an arc welding machine according to another embodiment of the present invention, and in FIG. 3, 1 to 10 are 1 to 1o in FIG.
This is the same part.

11.12 is a diode connected between the collector emitter of transistors 3 and 4, and this diode 11.12
This is for bypassing and discharging the energy stored in the accelerator 6, which is generated when the transistors 3 and 4 are turned off, and protecting the transistors 3 and 4 from the stored energy.

13 is a reactor 6, a welding electrode 6. A thyristor connected in parallel to a series circuit consisting of a welding arc 7, a base metal 8, and a shunt 9, is used to prevent the accumulation of acdle 5, which occurs when transistor 3 is turned off during the time TRP when transistor 3 supplies a reverse polarity output. The energy is from this thyristor 1
3, and the welding arc 7 is maintained by this. Note that this thyristor 13 is OFF during the time period TsP in which it supplies a positive output. Also, during the period TsP, the transistor 4 is not switched and is ON! The current and voltage are controlled by the resistor 14.

FIGS. 4a to 4d show a comparison of all welding results obtained when welding was performed using the arc welding machine of the present invention under various welding conditions. In FIGS. 4a to 4d, 16 is a base metal, and 18 is a weld bead. In addition, under the welding conditions of the welding results shown in Figure 1 4 a to d, the wire feed rate 2 frequency is s
The conditions were all the same for 1 minute and 66 clothes.

In addition, in Fig. 4a, the welding current is 117 μm, and the welding voltage is 34 μm.
・sV, the welding results when the ratio of the time TRP for supplying reverse polarity output to one cycle is 50%, and Figure 4 shows the welding current 124 μm, the welding voltage 134 V, and the time TRP
This is the welding result when the proportion of
Figure C shows welding current of 119 μm, welding voltage of 34 V, and time of T.
This is the welding result when the ratio of RP is 98%,
Fig. 4 d shows welding tRk” OAs welding Tli pressure k 2
s V, time This is the welding result when the ratio occupied by TFIP is 10%.

As shown in FIG. 4 a - d, when the arc welding machine of the present invention is used, by changing the ratio of the time TRP for supplying reverse polarity output and the time TsP for supplying positive polarity output, it can be used as a welding electrode. The depth of melt penetration of the wire and the amount of spatter generated per bead width can be changed.

As described above, when the arc welding machine of the present invention is used, the time TRP during which the reverse polarity output is supplied in the AC output, the time TBPs during which the positive polarity output is supplied, and the peak of the current during the period during which the reverse polarity output is supplied. The values can be easily changed, and the welding results such as the melting amount of the wire as a welding electrode, the penetration depth, and the bead width can be arbitrarily controlled. It is possible to perform welding in such a way as to obtain the optimum welding result for the thickness of the object.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an arc welding machine according to one embodiment of the present invention, Fig. 2 is an output characteristic diagram of the welding machine, and Fig. 3 is a circuit diagram showing an arc welding machine according to another embodiment of the present invention. , FIGS. 4a to 4d are cross-sectional views showing an example of welding results by the arc welding machine of the present invention.01.2...DC power source, 3,
4...Transistor, 5...Reactor, 6...l...Welding electrode, 7...Welding 7
Arc, 8... Base material, 10... Control circuit. Figure 11 Figure 2 Figure 3 1θ / Figure 4

Claims (1)

[Claims] A DC power source for reverse polarity output is connected to the series circuit with the welding arc handler through the first switching transistor, and a DC power source for positive polarity output is connected through the second switching transistor, and The variable time TRP and the time 'I'sp constitute one cycle, and during the period of the time TRP, the second switching transistor is turned OFF, the first switching transistor is turned ON-OFF, and the time T8f is set. ', the first switching transistor 'f: o
yy, the second switching transistor is turned ON-OFF, and the cycle is repeated.