Analytic and experimental investigation on deep hole formation process of covalent bond-ceramics in laser processing

Abstract

This paper described a mechanism of deep hole drilling of covalent bond-ceramics using a pulsed YAG laser beam. The deep hole drilling process was simulated by a newly developed analysis method, It was combined the ray tracing method for a laser power intensity distribution analysis and difference method for a thermal analysis, it was assumed that laser beam energy was delivered by reflection from the internal wall surface of a hole in the ray tracing model. Sublimation process of silicon nitride ceramics was considered during the thermal analysis. The deep dirlling hole was processed mainly by the energy reflected from the internal wall surface of the hole. In this process laser power intensity became higher in the center of the hole, since the laser beam was focused by the wall-reflecting effect.This paper described a mechanism of deep hole drilling of covalent bond-ceramics using a pulsed YAG laser beam. The deep hole drilling process was simulated by a newly developed analysis method, It was combined the ray tracing method for a laser power intensity distribution analysis and difference method for a thermal analysis, it was assumed that laser beam energy was delivered by reflection from the internal wall surface of a hole in the ray tracing model. Sublimation process of silicon nitride ceramics was considered during the thermal analysis. The deep dirlling hole was processed mainly by the energy reflected from the internal wall surface of the hole. In this process laser power intensity became higher in the center of the hole, since the laser beam was focused by the wall-reflecting effect.