Dynamic force balance model for metal transfer analysis in arc welding

Abstract

A dynamic force balance model is proposed by introducing the inertial force to predict metal transfer in arc welding. The dynamics of the pendant drop is modelled as a linear time-varying second-order system and the spring constant and electromagnetic force are calculated for the ellipsoidal drop. Two methods are employed to estimate the spring constant: numerical calculation for the ellipsoidal drop and a closed-form equation for the spherical drop at equilibrium. The inertial force is produced by drop oscillation and it is applied to the drop-detaching criterion. Since the inertial force reaches half the electromagnetic force at the transition current, it influences drop detachment with current increase. The proposed dynamic force balance model predicts the resonance frequency and detaching drop size with reasonable accuracy.