Lissajous curve oscillations in laser welding

In this study, a new approach for laser beam oscillations in welding is proposed. Commonly frequency is used as the principal process parameter when driving beam oscillation but often leads to a suboptimal fluence distribution. If velocity is modulated this presents significant opportunity for enhancing thermal distribution within welds. Controlling galvanometer velocity instead of the frequency will create ‘trajectory’ dependent fluence distribution opportunities. Here we investigate the use of Lissajous curves for this purpose since these allow rapid parametric design adaptation. Fluence profiles are obtained, analysed and presented. Using this method key melt pool characteristics can be modulated including temperature difference within weld, max temperature achieved and the cooling rate. To illustrate this, we present a series of remelted surfaces which show the effect of modulated fluence on weld morphology.