Droplet detachment regimes in annular laser beam droplet generation from a metal wire

Pendant droplet detachment regimes in the novel annular laser beam droplet generation from a metal wire are analyzed. In drop-on-demand generation, droplet detachment can be achieved via Rayleigh-Plateau instability based molten wire column break-up. Detachment dynamics are influenced by the distance between the annular laser beam focus and the pendant droplet neck. In the continuous generation of a droplet sequence, droplet detachment is governed by the laser pulse frequency, resulting in a spontaneous, resonant, or Rayleigh-Plateau instability based detachment regime. In addition to drop-on-demand generation, continuous droplet generation with spontaneous and mass-spring resonant detachment are suitable for metal droplet based engineering applications where accurate droplet diameter and deposition position are required. (C) 2014 CIRP.