Piezoelectric Actuation And Arc Force Based Control Of Metal Transfer In CO₂ Welding

In order to achieve the GMAW heat transfer and mass transfer decoupling as the goal,to the droplet transfer the most difficult CO2 welding process as the object,put forward a piezoelectric driven additional external force droplet transition control new method: The use of piezoelectric actuator ultra-high response speed real-time dynamic adjustment of its wire on the pressing force,adjust the wire speed to precision control of welding arc length;Timely reduce the welding current to minimize the arc repulsive force,so that the drop from the fall to the vertical drop;Piezoelectric displacement can fully release the lock-up transient down along the wire so that the droplet detachment inertial force,so as to obtain a stable CO2 welding spatter axially consisting of transition at a sufficiently large current in particular the low current range,greatly expand its scope of application.Through the simulation software Surface Evolver,the numerical simulation of the free transition of CO2 welding is realized,and the influence of the pulse current and its additional external force on the droplet was simulated and analyzed respectively.The results show that the synergistic effect can cause the droplet to reach the necking state,promote the free transition of droplets.The simulation results show that the droplet is repressed by the arc force squeezing at the rising edge of the pulse,the pulsed falling edge decreases the arc force,and the droplet drops to the vertical state.And when the base current is small,the peak current is larger,the peak time is shorter.The droplets can be controlled to be axially compressed during peak periods without radial deflection,in the current switch to the base value instantaneous droplet began to produce a stronger axial oscillation,the droplet oscillation momentum can promote the droplet transfer.It is verified that the influence of the start-up of the piezoelectric drive control wire on the droplet transfer is verified,found clamping longer,the shorter the time the droplet release the smooth transition,the smaller the drop.The higher the frequency,the smaller the droplet size.In the MIG welding,to achieve a stable pulse of a welding process.Set the pulse current waveform and piezoelectric drive coordinated control of the waveform,The realization of the CO2 in the pulse current generated by the oscillations and piezoelectric driving force applied under the joint action,can promote the droplets in the form of small droplets free transition to the pool.In this paper,a new simple,low-cost GMAW arc length fine adjustment and droplet transfer control method is provided for CO2 welding.It is also suitable for MIG / MAG welding.In addition,underwater high pressure dry GMAW arc also exclusion of droplets,droplet transfer behavior similar to CO2 welding.Therefore,the research of this subject has practical guidance value for high pressure dry GMAW metal transfer control.