Laser percussion drilling of highly reflective metals with external interdigital electrodes

In this study, a novel interdigital electrode was employed during the laser percussion drilling of highly reflective materials. The main advantage of using interdigital electrodes is one-sided access for removing the charged particles in the plasma plume. Another benefit is the acceleration effect on the particles, which increases the drilling performance. Different configurations of interdigital electrodes were proposed and investigated in this work to provide a simple, low-cost method for expelling the laser-induced plasma plume generated during the laser percussion drilling process. Electrical fields with different electrode configurations applied to the charged particles carrying the ions were also simulated in this work. The results show that vaporized debris is expelled by applying an electrical field, and hence the penetration depth can be maximally increased by 84.9% through an optimal electrode configuration. Although the electrical field strength and drilling efficiency of interdigital electrodes show an underperformance compared with the plane electrodes, the lifetime of interdigital electrodes outperforms that of the plane electrodes owing to a less-scattered particle deposition.