Real-time control of laser-hybrid welding using weld quality attributes

Abstract

Applied Thermal Sciences, Inc is developing and validating an automated, large-scale laser GMAW-assisted welding process that can be utilized to fabricate high-precision lightweight structural shapes for shipbuilding and other industries. At the heart of this laser welding process is a real-time, adaptive Process Control System (PCS). This PCS is unique in that it utilizes weld quality attributes as process control variables. The system integrates these weld quality variables along with the more traditional process parameters such as laser power, wire feed, GMAW voltage and active seam tracking. This PCS has sufficient bandwidth and response time to achieve welding speeds up to 600 inches/minute. The high degree of integration of the various subsystems allows the PCS to coordinate and accurately regulate all of the necessary tasks in real-time during the laser welding process. In addition to process control, the weld quality attributes are also extracted and provide immediate documentation of weld quality. Thus, the system performs, at high speed, weld quality inspections that were previously manually performed offline. By eliminating manual inspection, product throughput is increased and product costs are reduced. This paper describes the laser welding PCS designed for a fully integrated prototype facility. While the prototype facility uses a 25 kW CO2 laser, the PCS is adaptable to any type, power and wavelength of laser, and will be integrated with a high power Ytterbium fiber laser in the near future.Applied Thermal Sciences, Inc is developing and validating an automated, large-scale laser GMAW-assisted welding process that can be utilized to fabricate high-precision lightweight structural shapes for shipbuilding and other industries. At the heart of this laser welding process is a real-time, adaptive Process Control System (PCS). This PCS is unique in that it utilizes weld quality attributes as process control variables. The system integrates these weld quality variables along with the more traditional process parameters such as laser power, wire feed, GMAW voltage and active seam tracking. This PCS has sufficient bandwidth and response time to achieve welding speeds up to 600 inches/minute. The high degree of integration of the various subsystems allows the PCS to coordinate and accurately regulate all of the necessary tasks in real-time during the laser welding process. In addition to process control, the weld quality attributes are also extracted and provide immediate documentation of weld quality...