Mask assisted laser percussion drilling

In this work, a mask assisted laser micromachining was presented. The mask was placed upside the workpiece, and a laser beam passed through the opening hole inside the mask. Part of the plasma debris would splash on the mask through the induced shock wave when laser was striking the work-piece. Other parts of the plasma debris passed through the mask directly. The plasma debris sputtered around the top of the mask surface and avoided the plasma debris to be deposited around the drilled hole inlet. Two different camera configurations (i.e., coaxial setup and radial setup) were designed to capture the image of the plasma. By analyzing the image, the area and height of the plasma were measured at three different laser radiation energy. The hole size of mask was determined by correlated the area and height of the plasma image. Experimental results show that the processing efficiency of the laser drilling was increased to 29% and the debris height was decreased to 51% when the mask was employed to assist laser micromachining.