Research Of GMAW-P Droplet Transfer Cooperated Control

GMAW-P (Pulsed MIG Welding) is a high effect and high quality welding method. The Melt Metal Droplet transferred is controlled by the pulsed current mostly ,with less spatter ,nice figure and high quality. It can achieve a steady spray transfer in the current range from shoot circuit transfer to spray transfer of common GMAW. It is in favor of thin board welding, thick board welding, and all position welding. GMAW-P adapts welding heat sensitive material also. GMAW-P will be used further and further.Advanced requirement is put forward to the welding equipment for meeting higher welding quality. One droplet per pulse transfer in GMAW-P droplet transfer ,forms is the most favorable transfer mode. It is important to further improve GMAW-P welding techniques performance and corresponding steady process results by droplet transfer cooperated control design in welding machine research.In the basis of analysis of droplet transfer physics phenomenon, this paper clarifies GMAW-P wire melting, the forces acting on the droplet, factors and rules of effecting on GMAW-P droplet transfer. Waveform of pulse current is brought forward, that enhances droplet's controllability. These process methods by droplet transfer cooperated control and arc length closed loop control project can improve droplet diameter and arc length and arc stability.This paper presents an integrated simulation model for full digital controlled PMIG welding system with Matlab/Simulink. The simulation results were utilized to study the issues of digital control PMIG welding in this paper.The Control loop is a full digital control system introduced by taking "DSP+MCU" as the core. Digital wire feeder, display board and main board make up of welding machine net. The system achieves current and voltage closed loop control by software. The current loop controls current wave fine, that gets the one pulse one droplet. The voltage loop controls arc length , get steady arc and improve the arc length consistency. Expert database realize the synergic adjustment and droplet transfer cooperate control.The results of the experiment show that the full digital GMAW-P inverter with well control ability of droplet transfer realizes one pulse one droplet and has the high arc length consistency. Multi-material will be weld by changing the pulse current wave form.