Process optimization in Nd:YAG laser microdrilling of alumina–aluminium interpenetrating phase composite

In laser beam micromachining process, the quality of the drilled hole is of great importance. The quality of the microdrilled hole mainly depends on appropriate selection of process parameters. Predefined diameter of hole with minimum taper is of today's demand. The composite used for microdrilling operation is alumina–aluminium (Al2O3–Al) interpenetrating phase composite (IPC), which is widely used in aircraft and space stations. Until date, no experimental study has been done to obtain microdrilled hole of desired diameter. In the present paper three hole qualities such as hole diameter at entry, at exit and hole taper have been optimized individually as well as simultaneously using a central composite design (CCD) based on response surface methodology (RSM) during pulsed Nd:YAG laser microdrilling operation on alumina–aluminium IPC sheet of 1.14mm thickness. The analysis of variance (ANOVA) test has also been done to identify the process parameters that contributed the most to get desired hole quality.