Pulse Puddle Arc Welding (PPAW) creates a pulsating weld puddle while the weld metal is being deposited.
The idea of pulsating a liquid as it is being poured and solidifying is not new.This has been done for many years in cement, castings, dental, prostheses, and many other industries.
In contrast to pulsating the "current", PPAW pulsates the base metal of the weldment as the molten weld metal is deposited. This allows for an optimized level of pulsating the liquid puddle, perfect for the weldment.
PPAW will relieve the thermal stresses as they are being introduced during weld solidification. This procedure produces several desirable benefits for the weld metal and the heat affected zone. Two major benefits are the minimizing, if not totally eliminating, weld cracking and weld distortion.
Other benefits include welding faster by increasing amperage which also allows deeper weld penetration. Metallurgically, PPAW produces a finer, more uniform weld grain structure, thus improving the weld's mechanical properties and ultimate fatigue life. Weld ductility, in particular, is increased as much as 400% over a non-PPAW weld!
In many PPAW applications the process also stress relieves the weldment, therefore no additional post weld stress relief is needed.
PPAW is a simple procedure and can be adapted to most all arc welding situations. The pulsator is attached to the weld table or directly to the work piece. The sensor, to determine the vibration amplitude, is also attached.
With the control wand, the welder then fine tunes the pulse rate which varies from job to job because of variations in weight and rigidity.