Numerical study of the effect of the oscillation frequency in buttonhole welding

A three-dimensional transient simulation was conducted with comprehensive models of the laser welding process with a combination of wire feeding and one-dimensional sinusoidal beam oscillation. Both a realistic filler wire feeding and simultaneous melting by oscillating laser beam were considered. The buttonhole formation, which was shown in the simulations, was affected by the shape of the molten filler wire, e.g. the length and angle. The buttonholes formed at higher oscillation frequencies and became clearer with increasing oscillation frequency. The so-called chopping frequency of the wire, found in the frequency domain through Fourier analysis, became more dominant with increasing oscillation frequency. The wire chopping process seems to affect the number of multiple reflections, the power absorption, and the buttonhole behavior.