Real-time observation of crack propagation and stress analysis during laser cutting of glass

Abstract

Laser cutting of glass using a continuous-wave laser is attracting considerable attention because of its high processing speed and minimized generation of microcracks. During laser cutting of glass, a crack develops because of thermal stress and divides the glass plate. In this study, we observed crack propagation during laser cutting of glass in real time and found the distance between the crack tip and the laser irradiation position was 150 μm. Furthermore, we investigated the influence of the distance between the crack tip and the laser irradiation position on stress distribution and the stress condition necessary for crack growth. The results show the maximum principal stress at the crack tip increased as the distance between the crack tip and the laser irradiation position increased. In addition, we found that the crack developed when the maximum tensile stress of the crack tip reached 99 MPa. These results can be expected to enable the control of crack propagation and the estimation of appropriate processing conditions during laser cutting of glass.