A Study of Picosecond-Laser Drilling Technique in Ceramics

In this paper, the technique of drilling process with picosecond(ps) laser is studiedinAl2O3 ceramics. The defocus method is used to drill the ceramic slice, which is able to improve thedrilling ratio of depth to diameter.It is found out that the best location ofthis ps-laser is about0.15mm under the lower surface of workpiece,demonstrating the difference from nanosecond(ns)-laser machinein the respective ofdefocusing.The impact of the power and the processing speed isinvestigated on the quality of the drilling. For ps-laser machine,a smaller and high qualitythrough-holeis achievable by increasing the power of laser and reducing the speed of process, withthe ratio of depth to diameter from 3.12 to 4.27.The ratio can be further increased upto 6.25,throughoptimization of these three parameters: defocusing amount, laser power and laser processing speed.