Sensing and modelling of gas metal arc welding

Welding automation is normally concerned with directly controlling such factors as current, arc voltage, travel speed, and filler wire speed. Several other levels of control can be identified beyond present technology including control of weld heat input, cooling rate, and bead geometry (bead width, penetration, reinforcements, and defects). This work describes the development of a steady-state model of the gas metal arc (GMA) welding process which allows independent control of the heat and mass input to the base metal. An electro-optical technique for measurement of the welding pool and groove geometry is also described along with an ultrasonic method for sensing the weld bead. 5 refs., 5 figs., 1 tab.