JPH0822460B2 - Consumable electrode type pulse welding power supply - Google Patents

Description

TECHNICAL FIELD The present invention relates to a consumable electrode for performing welding by splitting a welding current into a pulse portion and a base portion and outputting the welding current interchangeably to separate the molten portion at the tip of the welding wire in a spray form. The present invention relates to a power source for pulse welding.

2. Description of the Related Art The pulse current rising slope and the pulse current falling slope of the conventional consumable electrode type pulse welding power source are determined by the reactor in the welding power source connected in series with the welding arc. Therefore, in order to change these gradients, the number of turns of the reactor has been changed so as to slow down the pulse current gradient and improve arc characteristics by using an extension cable. In addition, the conventional pulse welding power source, which controls the welding output control element in detail and changes the rising and falling gradients of the pulse current to prevent the arc blow phenomenon and improve the arc characteristics, cannot control these gradients. It was set manually according to the situation, regardless of the setting value of the output adjuster that sets the welding output.

Problems to be Solved by the Invention The purpose of pulse welding is originally to force spraying by applying a sharp pulse current rise or peak value in the low-speed wire feed amount region (low current region) where spray transfer does not occur. This is for the purpose of reducing the amount of spatter, controlling the bead shape, and improving the welding efficiency. However, it is conventionally known that when the spray critical current value determined by the wire material and the wire diameter is exceeded, the spray transfer is performed without applying the welding output in a pulsed manner. In the region above the spray critical current value, rather than making the welding output into a steep pulse shape, the welding result and workability are better. For example, in the case of welding beads, when the welding current is applied flatly rather than in a pulsed manner, vibration due to the arc force of the molten pool is less, and as a result, good welding beads are obtained. Also,
Even in the case of an arc sound, the more abrupt a pulse current is applied, the louder the sound becomes metallic, which is not preferable in the work environment. Therefore, in the conventional pulse welding power supply, the number of turns of the reactor in the welding power supply connected in series with the welding arc is reduced in order to promote the spray transfer in the low current region, and conversely in the high current region, the number of turns of the reactor is reduced. No increase or pulse application MAG (MIG)
I had to switch to welding and deal with it.

Means for Solving the Problems In order to solve the above problems, the present invention uses a welding current as an input, and a current that alternately sets two values of a current setting value of a pulse current part and a current setting value of a base current part. A set value signal, a pulse rising slope setting signal that sets the rising speed of the pulse current when moving from the base to the pulse, and a pulse that sets the falling speed of the pulse current when moving from the pulse to the base. An arithmetic circuit unit that outputs a falling slope setting signal, the current setting value signal, the pulse rising slope setting signal, and the pulse falling slope setting signal as inputs, and the current setting value signal from the base unit to the pulse unit. The current command value signal that is the current setting value from the base section to the pulse section is output with a time gradient determined by the pulse rising gradient setting signal when A pulse gradient control circuit that outputs a current command value signal that is a current setting value from the pulse portion to the base portion with a temporal gradient determined by the pulse falling gradient setting signal when the signal transitions from the pulse portion to the base portion. Section, the current command value signal and the current detection value signal from the welding current value detection circuit section are input, and the current command value and the current detection value are compared so that the welding current value matches the current command value. A comparison control circuit section for controlling and outputting a control signal to a welding output control element, and when the welding current is small, a temporal gradient determined by the pulse rising gradient setting signal and the pulse falling gradient setting signal Is set to a steep large value, and when the welding current is large, the temporal gradient determined by the pulse rising gradient setting signal and the pulse With the above configuration, the temporal gradient determined by the downward gradient setting signal is set to a slow small value.When the welding current is small, the pulse rising gradient and the pulse falling gradient are set to a steep large value, and the pulse force Smooth welding with strong spray transfer can be achieved. Conversely, when the welding current is large, the pulse rising slope,
The pulse falling gradient is set to a slow and small value, and as a result, vibration of the molten pool is suppressed, a good weld bead is realized, and metallic arc noise can be reduced.

Embodiment FIG. 1 shows an embodiment according to the present invention. In the figure, 1
Is an input terminal of a welding power source, 2 is a welding main transformer section, 3 is a rectifying / smoothing circuit section, 4 is a welding output control element, 5 is a diode for current regeneration, 6 is a reactor, 7 is a shunt, and 8 is Output terminal of welding power source, 9 is a contact tip for energization, 10
Is a welding wire, 11 is an object to be welded, 12 is a welding current value detection circuit unit, 13 is a comparison control circuit unit, 14 is a pulse gradient control circuit unit, 15 is an arithmetic circuit unit, and 16 is a welding output adjuster.

The arithmetic circuit unit 15 can read the set value of the wire feeding speed (welding current) by the output adjustment signal from the welding output adjuster 16 set by the operator. With this, the pulse frequency, pulse current, base current, etc. are determined and output, but at the same time, a pulse with a large value that is steep as the welding current smaller than the spray critical current is set according to the wire feed amount. Outputs a rising slope setting signal and a pulse falling slope setting signal. When the wire feed amount is set to a large value and a welding current larger than the spray critical current is set, a pulse rising slope setting signal and a pulse falling slope that are slow and small are output. 2A shows an example of input / output signals of the arithmetic circuit unit 15 in the former case, and FIG. 2B shows an example of input / output signals in the latter case. The arithmetic circuit unit 15 which performs such an operation can be easily realized by a microcomputer or the like. FIG. 3 shows the arithmetic circuit section 15
15a is an embodiment in the case of using a microcomputer, 15a is an analog / digital conversion circuit section which also serves as an input port for converting an analog output adjustment signal into a digital signal and taking it into the microcomputer, and 15b is an output adjustment of the digital signal Output the pulse rising slope setting signal according to the output adjustment value Pulse rising slope output port 15c
The pulse falling slope setting signal is output to the pulse falling slope output port 15d, the pulse current setting signal is output to the pulse current setting output port 15e that also serves as a digital / analog converter, and the base current setting signal is output. An interval timer circuit that also functions as an output port and a timer circuit that outputs a signal to the base current setting output port 15f that also functions as a port and a digital / analog converter It is a CPU unit that outputs to the unit 15g. A program for realizing this can be easily realized by using the output adjustment value signal as an address and preliminarily storing the data of the pulse rising slope setting value and the pulse falling slope setting value as a table in the address. 15g is an interval timer circuit composed of a programmable timer IC. This is also a data table method similar to the above, which makes it easy to program a proper pulse cycle time and the time distribution of the pulse part and the base part in it. Can be set. 15h is the interval timer circuit 1
It is a switch element that selects either the pulse current setting signal or the base current setting signal by the output of 5 g and outputs it as a current setting value signal. The waveform shown in FIG. 2 can be realized by the above embodiment.

The current setting value signal, the pulse rising slope setting signal, and the pulse falling slope setting signal output from the arithmetic circuit unit 15 are input to the pulse slope control circuit unit 14, and the rising slope and falling slope shown in FIG. It is output as a current command value signal. The input / output waveforms shown in FIG. 4 are realized in the embodiment shown in FIG. In FIG. 5, 14a and 14b are cross-point switch ICs in which the switch at any of the intersections A to A is turned on by the D input which is a digital signal. An arbitrary series resistance value can be selected by combining this with the resistance values of the resistors 14c and 14d. A CR charging / discharging circuit is formed by this, the diodes 14e, 14f, and the capacitor 14g, and the gradient of the pulse rising portion is 14a, 14c, 14e, 14g, and the gradient of the pulse falling portion is 14b, 14d, 14f, 14g. It is possible to realize the input / output signal waveform as shown in FIG.

The signal of which the welding current value is detected by the shunt 7 is amplified by the welding current value detection circuit unit 12 to a level that can be easily handled by the control circuit, and the current detection value signal is the output from the pulse gradient control circuit unit 14. It is input to the comparison control circuit unit 13 together with the command value, and when the current command value is comparatively controlled and is larger than the current detection value signal, it is sent to the welding output control element 4 as an L level signal and when it is small, an H level signal. Output a control signal. Therefore, the transistor of the welding output control element 4 is turned off when the base terminal input is L and turned on when the base terminal input is H, and feedback control is performed so that the welding output has a waveform equivalent to the current command value signal. The input / output waveforms of the comparison control circuit section 13 in FIG. 5 are as shown in FIG. Note that a and b in FIG. 5 are a and b in FIG.
Corresponding to. As an example for realizing this operation, a commercially available arithmetic comparator can be easily used, and therefore an example of a concrete circuit will be omitted.

The above operation is realized by the above embodiment. Although the chopper method using a transistor is shown as an example of the configuration in FIG. 1, this may be an inverter method, which does not change the gist of the present invention.

EFFECTS OF THE INVENTION As described above, according to the present invention, a pulse waveform having a steep rising edge and a falling edge can be formed in a low current region where the wire feed amount is low. As a result, the spray transfer is stabilized and the wire feed amount is reduced. In the high current region where the temperature is large, a pulse waveform with a gradual rise and fall gradient can be obtained, and as a result, the bead appearance is improved and the welding noise is reduced, which greatly contributes to the industry.

[Brief description of drawings]

FIG. 1 is a block diagram of a power supply for consumable electrode type pulse welding showing an embodiment of the present invention, FIG. 2 is a waveform diagram of input / output signals in an arithmetic circuit section of the power source, and FIG. 3 is a block of the arithmetic circuit section. Configuration diagram, FIG. 4 is an input / output signal waveform diagram in the pulse gradient control circuit section of the power supply, FIG. 5 is a circuit diagram of the pulse gradient control circuit section, and FIG. 6 is an input / output in the comparison control circuit section of the power supply. It is a signal waveform diagram. 4 ... Welding output control element, 12 ... Welding current value detection circuit,
13 …… Comparison control circuit section, 14 …… Pulse gradient control circuit section,
15: Arithmetic circuit section, 16: Welding output adjuster.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-57-112976 (JP, A) JP-A-57-118866 (JP, A) JP-A-62-167084 (JP, A)

Claims (1)

[Claims] 1. A current set value signal for inputting a welding current and alternately setting a binary current set value of a pulse current section and a current set value of a base current section, and a transition from a base section to a pulse section. An arithmetic circuit unit that outputs a pulse rising slope setting signal that sets the rising speed of the pulse current and a pulse falling slope setting signal that sets the falling speed of the pulse current when transitioning from the pulse unit to the base unit, A time determined by the pulse rising slope setting signal when the current setting value signal, the pulse rising slope setting signal, and the pulse falling slope setting signal are input, and the current setting value signal shifts from the base part to the pulse part A current command value signal that becomes a current setting value from the base part to the pulse part is output with a physical gradient, and the power setting value signal is output from the pulse part to the base part. A pulse gradient control circuit section that outputs a current command value signal that is a current setting value from the pulse section to the base section with a time gradient determined by the falling gradient setting signal, the current command value signal and welding current value Inputs the current detection value signal from the detection circuit, compares the current command value with the current detection value, controls the welding current value to match the current command value, and outputs a control signal to the welding output control element. And a comparison control circuit section for performing the welding current becomes small, the temporal gradient determined by the pulse rising gradient setting signal and the temporal gradient determined by the pulse falling gradient setting signal are steep and large values. When the welding current is large, a temporal gradient determined by the pulse rising gradient setting signal and a temporal gradient determined by the pulse falling gradient setting signal are set. Consumable electrode type pulse welding power source which is a chronic small becomes value.