Acoustic emission response of soda lime glass after a single Nd-YAG laser pulse

When machining brittle solids with a laser, crack formation can occur in the material around the irradiated area causing a strength reduction of the machined material. The purpose of this work was to study a well known brittle material (soda lime glass) by means of acoustic emission (AE) in order to investigate the correlation between visually observed crack formation and detected AE energy released by the crack formation in the material. During and after irradiation of soda lime glass with an Nd-YAG laser pulse, the number of hits and amount of AE energy were measured in the first 300 s using AE. It was found that it is possible to detect AE signals from cracks caused by irradiation with a single Nd-YAG laser pulse. The power of the detected signal is related to the amount of crack formation. Cracks can be minimized or avoided by choosing a suitable combination of pulse time and power density of the single laser pulse. The cracks which occur after a laser shot extend mainly in the radial direction from the irradiated area.