Regression modeling to predict the geometrical features of Ti6Al4V thin sheets butt joints welded by disk laser

The aim of this work is to investigate the effects of power, welding speed, defocusing on geometric features and on defects of 1 mm Ti6Al4V laser welded butt joints by a new generation disk laser with 2 kW of maximum power. Them active gain is a Yb:YAG disk instead of traditional Nd:YAG rods. Disk geometry allows to keep the nominal beam quality also at high power because there is no thermal lensing effect, typical of rod geometry. A three level Box-Behnken experimental design with three repetitions is carried out for a total of 45 tests. Linear and quadratic regression equations are developed to relate the input factors to the output variables in order to predict the geometric features of butt joints.