A waveform control circuit for AC argon arc welding machine

Abstract

The invention discloses a waveform control circuit for an alternate current argon arc welding machine. The waveform control circuit is used for adjusting the positive and negative amplitude of square waves of the alternate current argon arc welding machine and is characterized by comprising a triangular wave generation circuit, a chopper circuit, a time delay circuit, a differentiating circuit, a rising edge and falling edge detection circuit and a given current selection circuit; the triangular wave generation circuit is used for generating a triangular wave; the chopper circuit is connected to the output end of the triangular wave generation circuit and is used for outputting the square wave with the output duty ratio adjustable; the time delay circuit is connected to the output end of the chopper circuit and is used for generating two complementary square wave drive signals; the differentiating circuit is connected to the output end of the chopper circuit and generates signals P1 and P2; the rising edge and falling edge detection circuit judges the rising edges and the falling edges of the square wave drive signals according to the signals P1 and P2; the given current selection circuit outputs a positive wave output control signal and a negative wave output control signal according to the square wave drive signals and the rising edges and the falling edges of the square wave drive signals.

Description

technical field [0001] The invention relates to welding technical equipment, in particular to a waveform control circuit for an AC argon arc welding machine. Background technique [0002] The polarity of the AC current is periodically changed, which means that in each cycle, the half-wave is DC positive connection, and the half-wave is DC reverse connection. During the positive half-wave period, the tungsten electrode can emit enough electrons to melt the workpiece without overheating, which is beneficial to the stability of the sub-arc. The oxide film formed on the surface of the workpiece during the half-wave of the reverse connection can be easily cleaned off to obtain a bright, beautiful and well-formed weld. In this way, the AC argon arc welding machine takes into account the cleaning effect of the cathode and the effect of less burning loss of the tungsten electrode and good arc stability. For active metals such as aluminum, magnesium, aluminum bronze and their alloys...

AI Technical Summary

Problems solved by technology

[0003] However, the existing technology also has certain limitations. When it is desired to achieve a strong cleaning effect, that is, when the duty cycle is reduced, it means that the welding strength is reduced and the welding speed is slowed down.

Conversely, when fast welding speeds are desired, the cleaning effect may not be ideal

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