Correlations between drops dynamics and the GMAW-P ARC stability

Abstract

In case of the pulsed gas metal arc welding process (GMAW-P), the metal transfer from the wire tip to weld pool is one of the most important phenomena. The paper presents a system designed by developing an appropriate weld quality model based on the optimum transfer and weld pool parameters and comparing it in realtime with the information provided by the monitoring system, becoming an effective quality assessment feedback loop. The drop transfer process in pulsed welding was investigated by a modern, discontinuous method, using high-speed video monitoring performed with High-Dynamic-Range-CMOS camera (HDRC), with an external trigger input and by current and voltage measurements. Real-time welding monitoring enables also the real time assessment of the welding quality, besides the usually envisaged process control. The metal transfer affects the arc stability, weld pool dynamics, joint penetration, weld bead geometry and spatter. The process of metal transfer is influenced by dynamic factors, thermal conditions and electromagnetic effects.