Beam Shaping to Control Weld Pool Oscillations

Abstract This study investigates asymmetric beam shapes to introduce keyhole oscillation and reduce porosity. Three different beam shapes were tested: Gaussian (benchmark), pre-post heating shape, and asymmetric shape, with varying power levels and welding velocities. CT scans revealed a reduction in porosity with the asymmetric beam shape. Thermal imaging showed oscillations in the keyhole area, with frequencies around 8 Hz and 10 Hz depending on the laser power, welding speed and beam shape. The findings suggest that quasi-static beam shaping can decrease porosity though keyhole wobbling induced by beam shaping, and it is assumed that these results can be generalized to static beam shapes as well. However, further experiments are needed to validate these findings and confirm the tendency for keyhole oscillation.