Product Code: PIC06_1005

Laser Cutting Ceramics using the Unstable Fracture Technique
Authors:
Chwan-Huei Tsai, Huafan University; Taipei Hsien Taiwan
Jian-Shiun Shiu, Huafan University; Taipei Hsien Taiwan
Presented at PICALO 2006

This study proposes a new laser cutting method that uses the unstable fracture technique. In this method, a diamond blade is used to scribe a groove along the desired cutting path in an alumina substrate. A defocused CO2 laser is applied to the substrate surface. As the laser moves a short distance, a short crack is generated through the edge of the substrate. When the laser direction is reversed to close the crack tip, a great thermal stress is induced at the crack tip and causes the substrate to break along the scribed line. The alumina substrate can be separated into two pieces in one second for the laser power of 30 W. The acoustic emission signals produced during the fracture process were obtained to analyze the crack growth phenomenon. The thermal stress distribution was analyzed using the finite element software ANSYS. SEM photographs of the breaking surface were obtained to analyze the cutting quality. The relationship between the laser power and cutting speed is discussed from the experimental results. These phenomena are explained using the stress analysis results. It was found that the laser cutting surface was free from micro-cracks and the surface quality is much better than that from mechanical breaking.