Influence of surrounding gas type and pressure condition on micro-drilling of silicon carbide by harmonics of Nd:YAG laser

Abstract

Micro-drilling characteristics of silicon carbide by fundamental wavelength and three kinds of harmonic of Nd:YAG laser were experimentally investigated in the viewpoints of surrounding gas type and the pressure condition. Moreover, its characteristics were discussed by the observation of plasma behaviour, flow filed and debris behaviour on the specimen surface with a high-speed camera. The cracks were observed around drilled hole under the argon surrounding gas condition due to the generation of high intensity plasma. On the other hand, the helium surrounding gas kept the plasma in the vicinity region on the top surface of specimen, and the surrounding area of drilled hole was remarkably roughened. The better surface integrity could be obtained under the appropriate combination of surrounding gas type and the reduced pressure conditions.Micro-drilling characteristics of silicon carbide by fundamental wavelength and three kinds of harmonic of Nd:YAG laser were experimentally investigated in the viewpoints of surrounding gas type and the pressure condition. Moreover, its characteristics were discussed by the observation of plasma behaviour, flow filed and debris behaviour on the specimen surface with a high-speed camera. The cracks were observed around drilled hole under the argon surrounding gas condition due to the generation of high intensity plasma. On the other hand, the helium surrounding gas kept the plasma in the vicinity region on the top surface of specimen, and the surrounding area of drilled hole was remarkably roughened. The better surface integrity could be obtained under the appropriate combination of surrounding gas type and the reduced pressure conditions.