Thermodynamics Process of Laser Drilling on Copper Surface
LI Shi-wen1, 2, ZHANG Qiu-hui3, NIU Rui-hua4
1. School of Mathematics and Computer Science，Panzhihua University，Panzhihua 617000，China 2. College of Electronics & Information Engineering, Sichuan University, Chengdu 610064, China 3. Department of Electrical Information Engineering, Henan Institute of Engineering, Zhengzhou 451191, China 4. Southwest Institute of Technical Physics, Chengdu 610041, China
Abstract：The laser drilling experiment was carried out on the copper surface by ns laser pulse, then the micro-morphology of the micro-hole was observed and the thermodynamic process was analyzed accordingly. The research results show that micro-hole is made of the pit in the center and surrounding uplift. The pit becomes deeper with the incident laser pulse energy. The thermodynamic analysis indicates that laser drilling on the metal requires two basic conditions: the first is the deposition of laser pulse energy, which makes the occurrence of melting, vaporization and ionization. Such phase transition can make the materials easy to remove and the laser plasma can accelerate the laser pulse energy deposition as the secondary heat source. The second condition is the production of the laser plasma shock wave, it can eject the materials of phase transition effectively and timely, thus the micro hole can be formed.
