An investigation on stability of laser hybrid arc welding

The stability of the weld surface quality resulting from laser–arc hybrid welding of 4 mm thick steel was studied. The trends of stability in terms of top weld width variation were estimated by using design of experiments, where different types of unstable welds were distinguished. High speed imaging of the process supported the interpretation of the trends. High arc voltage and short distance laser–arc has destabilized the process. For a stable process the applied spray mode has caused a short arc and symmetric central drop transfer while for high voltage the arc became long and wide and the drops traveled sideward. The potential and limits of the design of experiments method for such kinds of applications were discussed.

► Fiber laser–MAG hybrid welding stability is investigated by DOE and high speed imaging.
► Parameters varied for DOE analysis are voltage, distance laser–arc, and laser beam power.
► The interpretation of the DOE-results is supported by high speed imaging.
► Short distance laser–arc as well as high laser power can also cause instabilities.