Cutting thin glass by femtosecond laser ablation

The femtosecond laser ablation process for cutting thin aluminoborosilicate glass sheets of thickness 100 mu m was investigated with emphasis on effective cutting speed (V-eff) and mechanical strength of diced samples. The process parameters including the laser fluence (F), overlap ratio (r) of the laser beam and polarization direction were varied at a fixed pulse repetition rate f= 1 kHz to find the optimal process condition that maximizes V-eff and edge strength. A three-point bending test was performed to evaluate the front-side and back-side bending (edge) strength of the laser-cut samples. V-eff was proportional to F unless r exceeded a critical value, at which excessive energy began to be delivered at the same spot. The front-side edge strength was bigger than the back-side strength because of the back-side damages such as chipping. Good edge strength, as high as similar to 280 MPa (front-side) and similar to 230 MPa (back-side), was obtained at F = 19 J/m(2), r = 0.99, with laser polarization vertical to the cutting path. (C) 2017 Elsevier Ltd. All rights reserved.112sciescopu