A Swing Arc System for Narrow Gap GMA Welding

A novel swing arc system was developed to realize high quality narrow gap GMA welding at low cost. This system uses a motor of hollow axis to turn directly the micro-bent conductive rod and then to weave circularly the arc around itself axis of torch, and can automatically search for the midpoint of symmetrical swing trail and detect precisely swing frequency in real time. Three mathematical models are also presented to calculate precisely key swing variables from torch structure and process parameters. Experimental results show that weld surface curvature and the penetration into groove sidewalls increase and weld sectional thickness decreases with increasing swing frequency and at-sidewall staying time of arc, while bottom shape of bead varies from single to twin peaks. This swing arc process thus improved obviously narrow gap weld formation.