Machining characteristics of glass substrates containing chemical components in femtosecond laser helical drilling

The machining characteristics of glass substrates containing chemical components were investigated for the purpose of femtosecond laser helical drilling. A femtosecond laser of wavelength 1552 nm and pulse duration 800 fs was adopted in the laser machining system. The substrates investigated were aluminosilicate, soda-lime, and borosilicate glass. The chemical components contained in each glass substrate were quantitatively analyzed by laser ablation-induced chemical plasma mass spectrometry. The characteristics of the drilling conditions for each glass substrate were affected by its chemical components. As the wt% of Al₂O₃ and MgO components in the glass substrates increased, the ablation threshold energy of each substrate decreased, resulting in greater vertical speed of the laser head.