Four different waveforms available with AC polarity welding are advanced square wave, soft square wave, sine wave, and triangular wave. Each wave changes the arc and puddle characteristics as well as the penetration profile.
Advanced square wave. The advanced square wave waveform offers fast transitions between EN and EP for a responsive, dynamic, and focused arc with better directional control. It forms a fast-freezing puddle with deep penetration and fast travel speeds.
Soft square wave. Soft square wave provides a smooth, soft, “buttery” arc with a fluid puddle and good wetting action. The puddle is more fluid than with advanced square wave and more controllable than with sine wave.
Sine wave. The sine wave offers a soft arc with the feel of a conventional power source. It provides good wetting action and actually sounds quieter than other waves. Its fast transition through the zero amperage point also eliminates the need for continuous high frequency.
Triangular wave. The triangular wave offers peak amperage while reducing overall heat input into the weld. This leads to quick puddle formation, low weld distortion, and fast travel speeds. It is especially good for welding thin aluminium.
Reference: Riding the right wave in aluminum welding-www.thefabricators.com
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