Pulsed LASER-(micro)TIG hybrid welding: Process characteristics

A variant from the laser-arc hybrid welding process family which combines a pulsed laser process (Nd:YAG) and a pulsed (micro)TIG welding process is described. For studying the present variant process’ characteristics experimental work was carried out using video data acquisition and thermal imaging. In this paper, the characteristics of the present hybrid welding process variant and the influence of TIG welding parameters onto the process stability and the welding process result are presented. The experimental work revealed that the transient hybrid coupling phenomena, which is specific to the present hybrid process variant, has an important influence onto the process stability and the processing result. At the same time a strong interaction between the controlled process parameters was observed and that rather small changes to the process parameters values have a strong effect onto the process stability. The recommended TIG frequency domain for using as well as the variant which provides the best option to attenuate the penetration variation, specific to pulsed laser welding, was determined. The TIG frequency values which seem to lead to a stable welding process are of the same order as the ones used for laser pulse repetition rates. The variant that leads to an attenuation of the penetration is pulsed TIG-laser (with TIG as the leading process).