Femtosecond Laser Induced Periodic Surface Structures on Copper: Modeling and Experimental Comparison

• Main Authors: Chang, Chin-Lun, 張晉綸
• Other Authors: Cheng, Chung-Wei
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/e983a7

碩士 === 國立交通大學 === 機械工程系所 === 106 === When irradiating a metal surface with femtosecond laser pulses, quasi-periodic nanostructures can be directly formed in one-step process. This technique is referred to as femtosecond laser-induced periodic surface structures (FLIPSS). FLIPSS can be applied to many different application fields, e.g. biomedical or change material surface physical properties. But the application of using FLIPSS on the electrode of Electric discharge machine (EDM) has not been studied widely. This study is target to use the electrode processed with FLIPSS do the EDM machining, by using the tip discharge effect transfer the periodic nano structure to the workpiece surface. In this study, FLIPSS on the surface by single femtosecond laser pulse of a copper material, which is common used for EDM electrode, was investigated here in both theoretically and experimentally. The practical use of EDM experiment is studied by our cooperator, will not mention in this study. The numerical analysis was performed using a two-dimensional two-temperature model (TTM) with a modified Drude optical model to get dynamic optical parameters, a sinusoidal distribution laser heat density, and phase change and explosion models for evaporation. By using the proposed model, we can obtain FLIPSS formation result on copper at two different laser wavelength, 515 nm and 800 nm respectively.