Product Code: ICAL06_M1002

Effect of Laser Wavelength on Machining Characteristics of Aluminum Nitride in Micro-boring
Authors:
Norio KATAOKA, KATAOKA Corporation; Kyoto Japan
Yasuhiro OKAMOTO, Okayama Univeristy; Okayama Japan
Yoshiyuki UNO, Okayama Univeristy; Okayama Japan
Itaru TANINO, Okayama Univeristy; Okayama Japan
Presented at ICALEO 2006

Effect of laser wavelength on machining characteristics of aluminum nitride micro-drilling using harmonics of Nd:YAG laser was experimentally investigated. Drilled depth increased with decreasing the laser wavelength under the same machining condition, since photon energy and absorptivity become higher with decreasing the laser wavelength. Besides, the pulse energy affecting to material processing also became larger with decreasing the laser wavelength, since the transmittance ratio of laser beam in plasma increased with decreasing the laser wavelength. On the other hand, the drilled depth was greatly different by the kind of assist gas in the case of fundamental wavelength and SHG, while it was not influenced sensitively by the kind of assist gas in the case of THG and FHG because of its high photon energy. Moreover, the drilled depth became larger under the vacuum condition compared to the atmosphere condition. Shapes and elements of debris were different by the laser wavelength. The debris consisting of crystal due to heat cracking were observed in the case of fundamental wavelength, and the surface of debris by SHG was strongly oxidized. It was suggested removal by the photochemical reaction occurred in the case of THG, FHG and 5thHG, since aluminum, oxygen and nitrogen were detected from debris.