Current commercially available systems for pulsed gas metal arc welding (GMAW-P) monitor electrical characteristics of the arc and attempt to compensate for process deviations by pulsing current at a constant frequency. For highly critical GMAW-P applications in challenging materials like titanium, the present approach cannot simultaneously control arc stability, bead shape, and weld metallurgy. Furthermore, the systems available today cannot preclude the occurrence of instabilities over certain ranges of travel speed and arc voltage. We propose a multi-sensor, multi-objective sensing and adaptive control method that senses arc electrical characteristics, the dynamics of individual droplets in the GMAW process, and the dynamics of the weld pool. We utilize reconfigurable, intelligent phase locked loop technology in conjunction with very high speed data acquisition, non-imaging optical weld pool sensors, and fuzzy logic controllers to achieve a comprehensive control solution that addresses the shortcomings of currently available systems. Such a system will allow for the first time multi-objective control of arc stability, bead shape, and weld metallurgy.
Benefits: The successful implementation of our proposed technology will enable for the first time a comprehensive adaptive control for GMAW and GMAW-P that can simultaneously address arc stability, bead shape, and metallurgical effects. We expect and already have significant commercial interest in this technology solution expressed by defense manufacturers (GMAW-P of aluminum and other alloys), airframers (titanium material deposition and welding using various GMAW methods), aero-engine makers (GMAW-P of superalloys), heavy industry (GMAW-P weld repair of rails and equipment manufacture), and oil and gas (pipline welding, both land-based and off-shore).
Keywords: gas metal arc welding, GMAW, pulsed gas metal arc welding, GMAW-P, weld pool dynamics, high speed data acquisition, phase locked loops, fuzzy logic controllers
