2023 Volume 67 Issue 9 Pages 503-508
A new cutting method was developed for ultra-thin glass, which was difficult to cut by conventional methods. First, a crackless trench line was formed on the glass surface by scribing. Second, an assist crack was formed in the vicinity of the trench line. Then, crack propagation along either side of the trench line was induced from the assist crack. We investigated the crack formation and stress distribution by experiments and finite element method (FEM) to determine the directionality of crack propagation. On the crack propagation side, cracks perpendicular to the glass surface were observed along the trench line. On the other hand, cracks a few tens of microns in size deflecting from the trench line were formed on the other side. Numerical analyses indicated that the symmetrical distribution of shearing stress around the trench line contributed to the directionality of crack propagation. The crack propagation direction and stress distribution could be inverted by scribing conditions.
