Laser bending of brittle materials

Laser bending is a novel technique to modify the curvature of sheet metals or hard materials, which possesses practical values in forming brittle materials due to its advantages of non-mechanical contact, non-mould, short manufacturing cycle and small heat affected zone. In this paper, laser bending of brittle materials by CO2 CW laser and Nd:YAG pulsed laser is investigated, including mono-crystalline silicon, borosilicate glass and Al2O3 ceramic. For each material, the relations between processing parameters and bending angle were studied and the corresponding bending behaviors were analyzed to have a better understanding of the bending mechanisms behind. The results show that for the above three materials, an elevated substrate temperature needs to be applied to prevent brittle fracture, and the bending can be achieved with appropriate laser operation parameters. For silicon and ceramic materials, only bending toward the laser beam is obtained with narrow optimal processing parameter windows. While for glass, the sample not only can bend toward the laser beam but also bend away from the laser beam at a wide operation parameter window.