In Gas shielded Metal Arc Welding process, the molten drop at the electrode wire tip is detached and transferred into the weld pool by various driving forces, which have been discussed mainly focusing on gravity force, electro-magnetic force, surface tension force and plasma drag force. In this paper modeling of the oscillation phenomena of molten drop at the wire tip are described. An analytical model evaluating natural frequency of liquid pendant drop was proposed on the basis of mass-spring model. The numerical model developed is an axial symmetrical 2D model which enables to calculate and visualize time-change of the drop shape and the flow in the drop using VOF-CSF method. It is shown that the natural frequency of the pendant drop decreases with increase of the drop size by both analytical and numerical models. And the natural frequency evaluated by analytical model is shown to be little higher than that by numerical model because of neglecting viscous resistance of liquid flow.
